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1

Study of using oxygen-enriched combustion air for locomotive diesel engines  

SciTech Connect

A thermodynamic simulation is used to study the effects of oxygen-enriched intake air on the performance and nitrogen oxide (NO) emissions of a locomotive diesel engine. The parasitic power of the air separation membrane required to supply the oxygen-enriched air is also estimated. For a given constraint on peak cylinder pressure, the gross and net power output of an engine operating under different levels of oxygen enrichment are compared with those obtained when a high-boost turbocharged engine is used. A 4% increase in peak cylinder pressure can result in an increase in net engine power of approximately 13% when intake air with an oxygen content of 28% by volume is used and fuel injection timing is retarded by 4 degrees. When the engine is turbocharged to a higher inlet boost, the same increase in peak cylinder pressure can improve power by only 4%. If part of the significantly higher exhaust enthalpies available as a result of oxygen enrichment are recovered, the power requirements of the air separator membrane can be met, resulting in substantial net power improvements. Oxygen enrichment with its attendant higher combustion temperatures, reduces emissions of particulates and visible smoke but increases NO emissions (by up to three times at 26% oxygen content). Therefore, exhaust gas after-treatment and heat recovery would be required if the full potential of oxygen enrichment for improving the performance of locomotive diesel engines is to be realized.

Poola, R.B.; Sekar, R. [Argonne National Lab., IL (United States); Assanis, D.N. [Univ. of Michigan, Ann Arbor, MI (United States); Cataldi, G.R. [Association of American Railroads, Washington, DC (United States)

1996-12-31

2

The Economics of Oxygen Enriched Air Production Via Membranes  

E-print Network

Oxygen enriched air combustion is a recognized approach to energy conservation. Conventional methods of producing oxygen enriched air: Pressure Swing Adsorption and Cryogenics, are energy-intensive and expensive. In this paper the economics of using...

Gollan, A.; Kleper, M. H.

1984-01-01

3

Study of using oxygen-enriched combustion air for locomotive diesel engines  

SciTech Connect

A thermodynamic simulation is used to study effects of O2-enriched intake air on performance and NO emissions of a locomotive diesel engine. Parasitic power of the air separation membrane required to supply the O2-enriched air is also estimated. For a given constraint on peak cylinder pressure, gross and net power output of an engine operating under different levels of O2 enrichment are compared with those obtained when a high-boost turbocharged engine is used. A 4% increase in peak cylinder pressure can result in 13% increase in net engine power when intake air with 28 vol% O2 is used and fuel injection timing retarded by 4 degrees. When the engine is turbocharged to a higher inlet boost, the same increase in peak cylinder pressure can result in only 4% improvement in power. If part of the higher exhaust enthalpies from the O2 enrichment is recovered, the power requirements of the air separator membrane can be met. O2 enrichment with its higher combustion temperatures reduces emissions of particulates and visible smoke but increases NO emissions (by up to 3 times at 26% O2 content). Therefore, exhaust gas after-treatment and heat recovery would be required if the full potential of O2 enrichment for improving the performance of locomotive diesel engines is to be realized.

Poola, R.B.; Sekar, R. [Argonne National Lab., IL (United States); Assanis, D.N. [Michigan Univ., Ann Arbor, MI (United States); Cataldi, G.R. [Association of American Railroads, Washington, DC (United States)

1996-10-01

4

Reduction of NO{sub x} and particulate emissions by using oxygen-enriched combustion air in a locomotive diesel engine.  

SciTech Connect

This paper discusses operational and emissions results obtained with a locomotive (two-cylinder, EMD 567B) research diesel engine when oxygen-enriched combustion air is used. An operating regime was identified in which particulates and NO{sub x} could be reduced simultaneously when the concentration of intake air oxygen, fueling rate, and injection timing were optimized. Using oxygen from an external source, particulates were reduced by approximately 60% and NO{sub x} emissions were reduced by 15--20% with the optimal operating strategy. Higher gross power, lower peak cylinder pressures, and lower brake-specific fuel consumption were also observed. Gross power was increased by about 15--20% at base peak combustion pressure, and gross brake-specific fuel consumption was decreased by 2--10% with load. The effect of achieving oxygen enrichment by means of an air separation membrane is beyond the scope of the current study.

Poola, R. B.; Sekar, R. R.; Energy Systems; Electro-Motive Div., General Motors Corp.

2003-04-01

5

REDUCTION OF NOx EMISSION FROM COAL COMBUSTION THROUGH OXYGEN ENRICHMENT  

SciTech Connect

BOC Process Gas Solutions and Western Research Institute (WRI) conducted a pilot-scale test program to evaluate the impact of oxygen enrichment on the emissions characteristics of pulverized coal. The combustion test facility (CTF) at WRI was used to assess the viability of the technique and determine the quantities of oxygen required for NOx reduction from coal fired boiler. In addition to the experimental work, a series of Computational Fluid Dynamics (CFD) simulations were made of the CTF under comparable conditions. A series of oxygen enrichment test was performed using the CTF. In these tests, oxygen was injected into one of the following streams: (1) the primary air (PA), (2) the secondary air (SA), and (3) the combined primary and secondary air. Emission data were collected from all tests, and compared with the corresponding data from the baseline cases. A key test parameter was the burner stoichiometry ratio. A series of CFD simulation models were devised to mimic the initial experiments in which secondary air was enriched with oxygen. The results from these models were compared against the experimental data. Experimental evidence indicated that oxygen enrichment does appear to be able to reduce NOx levels from coal combustion, especially when operated at low over fire air (OFA) levels. The reductions observed however are significantly smaller than that reported by others (7-8% vs. 25-50%), questioning the economic viability of the technique. This technique may find favor with fuels that are difficult to burn or stabilize at high OFA and produce excessive LOI. While CFD simulation appears to predict NO amounts in the correct order of magnitude and the correct trend with staging, it is sensitive to thermal conditions and an accurate thermal prediction is essential. Furthermore, without development, Fluent's fuel-NO model cannot account for a solution sensitive fuel-N distribution between volatiles and char and thus cannot predict the trends seen in the experiment.

Western Research Institute

2006-07-01

6

Final report on the project entitled: Highly Preheated Combustion Air System with/without Oxygen Enrichment for Metal Processing Furnaces  

SciTech Connect

This work develops and demonstrates a laboratory-scale high temperature natural gas furnace that can operate with/without oxygen enrichment to significantly improve energy efficiency and reduce emissions. The laboratory-scale is 5ft in diameter & 8ft tall. This furnace was constructed and tested. This report demonstrates the efficiency and pollutant prevention capabilities of this test furnace. The project also developed optical detection technology to control the furnace output.

Arvind Atreya

2007-02-16

7

Combustion of coal chars in oxygen-enriched atmospheres  

SciTech Connect

This work pertains to the high-temperature combustion of pulverized coal chars under oxygen-enriched atmospheres. Single char particles were burned in a drop-tube furnace, electrically-heated to 1300-1500 K, in 21%, 50% and 100% O{sub 2}, in a balance of N{sub 2}. Their luminous combustion histories were observed with two-color ratio pyrometry. A solution of the Planckian ratio-pyrometry equation for temperature was implemented, extending on Wien's approximation. The temperature and time histories for 45-53 {mu}m bituminous chars experienced wide particle-to-particle disparity, and varied depending on oxygen mole fraction and furnace temperature. Average char surface temperatures increased from 1600-1800 K in air, to 2100-2300 K in 50% O-2, to 2300-2400 K in 100% O{sub 2}, at gas temperatures of 1300-1500 K, respectively. Combustion durations decreased from 25-45 ms in air, to 8-17 ms in 50% O{sub 2}, to 6-13 in 100% O{sub 2}. Thus, average particle temperatures increased by up to 45%, whereas burnout times decreased by up to 87% as combustion was progressively enriched in O{sub 2} until 100% was attained. The apparent and intrinsic reactivity of the chars burning at 1500 K gas temperature were found to increase by factors of to 8 and 35, respectively, as the oxygen mole fraction increased by a factor of five, from 21% to 100%.

Bejarano, P.A.; Levendis, Y.A. [Northeastern University, Boston, MA (United States)

2007-07-01

8

An oxygen enrichment attachment for use with humidified air  

PubMed Central

Jebson, P., Dewar, J., and White, J. (1974).Thorax, 29, 371-376. An oxygen enrichment attachment for use with humidified air. An oxygen enrichment attachment is described which fulfils the basic requirements for intubated patients. Using values for tidal volume and inspiratory time found in the type of patients for whom the attachment is intended, a range of mean inspired oxygen concentration has been given for 2, 4, 6, 8, and 10 1/min oxygen flow. Images PMID:4850557

Jebson, P.; Dewar, J.; White, J.

1974-01-01

9

Experimental Research of the Oxygen-Enriched Combustion of Sewage Sludge and Coal in CFB  

NASA Astrophysics Data System (ADS)

Sewage sludge is the by-products of sewage treatment, and it is a fuel of high moisture, high ash and low caloric. Oxygen-enriched combustion technology is one of the new and clean coal combustion technologies that can control pollutant emission, which makes CO2 separation, SO2 treatment become easier, and NOx emission reduced. In this paper, we carried out the experimental research on the advantages of oxygen-enriched combustion and the characteristics of sewage sludge in a CFB incinerator that the diameter of the furnace is 100 mm, It is an important foundation for the industrialized application of the oxygen-enriched combustion of sewage sludge and coal in CFB. Experimental analyzed on the combustion characteristics of three conditions in the oxygen concentration of 21%˜35%, which were the weight ratio of coal and sludge were 1?1, 1?2 and also the coal was given. Furthermore, the change of gas composition along with the change of oxygen content and the temperature of dense phase region was analyzed. The results showed that the combustion characteristics differ from the different mixing rate between coal and sludge in different oxygen atmosphere, when the fluidized air velocity was 1.56 m/s˜1.88 m/s, the combustion stability; When the amount of the fuel was constant, as the increase of the oxygen contents in the experimental atmosphere, the total air volume decreased, the furnace temperature increased gradually, the concentration of SO2 and NOx showed increasing trend, which is beneficial to the removal of SO2; The concentration of NOx was increased gradually as temperature of the fluidized bed increased.

Xin, S. W.; Lu, X. F.; Liu, H. Z.

10

Utilizing intake-air oxygen-enrichment technology to reduce cold- phase emissions  

SciTech Connect

Oxygen-enriched combustion is a proven, serious considered technique to reduce exhaust hydrocarbons (HC) and carbon monoxide (CO) emissions from automotive gasoline engines. This paper presents the cold-phase emissions reduction results of using oxygen-enriched intake air containing about 23% and 25% oxygen (by volume) in a vehicle powered by a spark-ignition (SI) engine. Both engineout and converter-out emissions data were collected by following the standard federal test procedure (FTP). Converter-out emissions data were also obtained employing the US Environmental Protection Agency`s (EPA`s) ``Off-Cycle`` test. Test results indicate that the engine-out CO emissions during the cold phase (bag 1) were reduced by about 46 and 50%, and HC by about 33 and 43%, using nominal 23 and 25% oxygen-enriched air compared to ambient air (21% oxygen by volume), respectively. However, the corresponding oxides of nitrogen (NO{sub x}) emissions were increased by about 56 and 79%, respectively. Time-resolved emissions data indicate that both HC and CO emissions were reduced considerably during the initial 127 s of the cold-phase FTP, without any increase in NO, emissions in the first 25 s. Hydrocarbon speciation results indicate that all major toxic pollutants, including ozone-forming specific reactivity factors, such as maximum incremental reactivity (NUR) and maximum ozone incremental reactivity (MOIR), were reduced considerably with oxygen-enrichment. Based on these results, it seems that using oxygen-enriched intake air during the cold-phase FTP could potentially reduce HC and CO emissions sufficiently to meet future emissions standards. Off-cycle, converter-out, weighted-average emissions results show that both HC and CO emissions were reduced by about 60 to 75% with 23 or 25% oxygen-enrichment, but the accompanying NO{sub x}, emissions were much higher than those with the ambient air.

Poola, R.B.; Ng, H.K.; Sekar, R.R. [Argonne National Lab., IL (United States); Baudino, J.H. [Autoresearch Labs., Inc., Chicago, IL (United States); Colucci, C.P. [National Renewable Energy Lab., Golden, CO (United States)

1995-12-31

11

Method and apparatus for reducing cold-phase emissions by utilizing oxygen-enriched intake air  

DOEpatents

An oxygen-enriched air intake control system for an internal combustion engine includes air directing apparatus to control the air flow into the intake of the engine. During normal operation of the engine, ambient air flowing from an air filter of the engine flows through the air directing apparatus into the intake of the engine. In order to decrease the amount of carbon monoxide (CO) and hydrocarbon (HC) emissions that tend to be produced by the engine during a short period of time after the engine is started, the air directing apparatus diverts for a short period of time following the start up of the engine at least a portion of the ambient air from the air filter through a secondary path. The secondary path includes a selectively permeable membrane through which the diverted portion of the ambient air flows. The selectively permeable membrane separates nitrogen and oxygen from the diverted air so that oxygen enriched air containing from about 23% to 25% oxygen by volume is supplied to the intake of the engine.

Poola, Ramesh B. (Woodridge, IL); Sekar, Ramanujam R. (Naperville, IL); Stork, Kevin C. (Chicago, IL)

1997-01-01

12

The balance model of oxygen enrichment of atmospheric air  

NASA Astrophysics Data System (ADS)

The study of turnover of carbon and oxygen is an important line of scientific investigation. This line takes on special significance in conditions of soil degradation, which leads to the excess content of carbon dioxide and, as result, decrease of oxygen in the atmosphere. The aim of this article is a statement the balance model of oxygen enrichment of atmospheric air (ratio O/C) depending on consumption and assimilation by plants of dissolved organic matter (DOM) and the value of the oxidation-reduction potential (Eh). Basis of model was the following: green vascular plants are facultative heterotrophic organisms with symbiotic digestion and nutrition. According to the trophology viewpoint, the plant consumption of organic compounds broadens greatly a notion about the plant nutrition and ways of its regulation. In particular, beside the main known cycle of carbon: plant - litter - humus - carbon dioxide - plant, there is the second carbon cycle (turnover of organic compounds): plant - litter - humus - DOM - plant. The biogeochemical meaning of consumption of organic compounds by plants is that plants build the structural and functional blocks of biological macromolecules in their bodies. It provides receiving of a certain "energy payoff" by plants, which leads to increase of plant biomass by both an inclusion of allochthonous organic molecules in plant tissues, and positive effect of organic compounds on plant metabolic processes. One more of powerful ecological consequence of a heterotrophic nutrition of green plants is oxygen enrichment of atmospheric air. As the organic molecules in the second biological cycle of carbon are built in plants without considerable chemical change, the atmospheric air is enriched on that amount of oxygen, which would be required on oxidation of the organic molecules absorbed by plants, in result. It was accepted that: plant-soil system was climax, the plant community was grassy, initial contents of carbon in phytomass was accepted as 1, annually from 60 to 100 % of the plant litter could arrive to the soil; coefficients of humification of both plant litter and DOM were 0.1 (10 %); DOM is formed as a result of hydrolytic destruction of plant litter, newly formed humic substances (HS) and humus; coefficient of possible absorption of DOM by plants - 0.1 (10 %); it was considered that all organic compounds affiliated into DOM had positive physiological effect on green plants; it was accepted that 1 % DOM absorbed by plants increases phytomass on 10 % (for example, at the expense of photosynthesis acceleration); Eh value was changed from 300 to 800 mV; depending on Eh (i) the coefficient of plant litter oxidation was in the range from 0.75 (75 %) to 0.8 (90 %), coefficient of oxidation of DOM and newly formed HS - from 0.85 (85 %) to 0.9 (90 %), and coefficient of humus oxidation from 0 (0 %) to 0.05 (5 %), and (ii) coefficient of hydrolytic destruction of plant litter and newly formed HS was in the range from 0.12 (12 %) to 0.07 (7 %), and coefficient of humus hydrolytic destruction from 0,05 (5 %) to 0 (0 %), accordingly; all dependences were quasilinear. The following conclusions have been made based on the modeling: (i) both phytomass and oxygen content in atmospheric air were increased with increase of DOM part absorbed by green vascular plants; (ii) the abundance of humus was increased with increase of DOM consumption by green plant (on 5 % at all Eh values) too; (iii) the increase of Eh with 300 to 800 mV led to reduction of oxygen in atmospheric air and to quadruple decrease of the abundance of humus.

Popov, Alexander

2013-04-01

13

Application of oxygen-enriched combustion for locomotive diesel engines. Phase 1  

SciTech Connect

A thermodynamic simulation is used to study the effects of oxygen-enriched intake air on the performance and nitrogen oxide (NO) emissions of a locomotive diesel engine. The parasitic power of the air separation membrane required to supply the oxygen-enriched air is also estimated. For a given constraint on peak cylinder pressure, the gross and net power outputs of an engine operating under different levels of oxygen enrichment are compared with those obtained when a high-boost turbocharged engine is used. A 4% increase in peak cylinder pressure can result in an increase in net engine power of approximately 13% when intake air with an oxygen content of 28% by volume is used and fuel injection timing is retarded by 4 degrees. When the engine is turbocharged to a higher inlet boost, the same increase in peak cylinder pressure improves power by only 4%. If part of the significantly higher exhaust enthalpies available as a result of oxygen enrichment are recovered, the power requirements of the air separator membrane can be met, resulting in substantial net power improvements. Oxygen enrichment reduces particulate and visible smoke emissions but increases NO emissions. However, a combination of retarded fuel injection timing and post-treatment of exhaust gases may be adequate to meet the locomotive diesel engine NO{sub x} standards. Exhaust gas after-treatment and heat recovery would be required to realize the full potential of oxygen enrichment. Economic analysis shows that oxygen-enrichment technology is economically feasible and provides high returns on investment. The study also indicates the strong influence of membrane parasitic requirements and exhaust energy recovery on economic benefits. To obtain an economic advantage while using a membrane with higher parasitic power requirements, it is necessary to recover a part of the exhaust energy.

Poola, R.B.; Sekar, R.R.; Assanis, D.N.

1996-09-01

14

The combustion kinetics of coal chars in oxygen-enriched environments.  

SciTech Connect

Oxygen-enhanced and oxygen-fired pulverized coal combustion is actively being investigated to achieve emission reductions and reductions in flue gas cleanup costs, as well as for coal-bed methane and enhanced oil recovery applications. To fully understand the results of pilot scale tests and to accurately predict scale-up performance through CFD modeling, accurate rate expressions are needed to describe coal char combustion under these unconventional combustion conditions. In the work reported here, the combustion rates of two pulverized coal chars have been measured in both conventional and oxygen-enriched atmospheres. A combustion-driven entrained flow reactor equipped with an optical particle-sizing pyrometry diagnostic and a rapid-quench sampling probe has been used for this investigation. Highvale subbituminous coal and a high-volatile eastern United States bituminous coal have been investigated, over oxygen concentrations ranging from 6 to 36 mol% and gas temperatures of 1320-1800 K. The results from these experiments demonstrate that pulverized coal char particles burn under increasing kinetic control in elevated oxygen environments, despite their higher burning rates in these environments. Empirical fits to the data have been successfully performed over the entire range of oxygen concentrations using a single-film oxidation model. Both a simple nth-order Arrhenius expression and an nth-order Langmuir-Hinshelwood kinetic equation provide good fits to the data. Local fits of the nth-order Arrhenius expression to the oxygen-enriched and oxygen-depleted data produce lower residuals in comparison to fits of the entire dataset. These fits demonstrate that the apparent reaction order varies from 0.1 under near-diffusion-limit oxygen-depleted conditions to 0.5 under oxygen-enriched conditions. Burnout predictions show good agreement with measurements. Predicted char particle temperatures tend to be low for combustion in oxygen-depleted environments.

Shaddix, Christopher R.; Murphy, Jeffrey J.

2004-09-01

15

Experimental and analytical study to model temperature profiles and stoichiometry in oxygen-enriched in-situ combustion  

E-print Network

EXPERIMENTAL AND ANALYTICAL STUDY TO MODEL TEMPERATURE PROFILES AND STOICHIOMETRY IN OXYGEN-ENRICHED IN-SITU COMBUSTION A Dissertation by JOSE RAMON RODRIGUEZ Submitted to the Office of Graduate Studies of Texas A... AND STOICHIOMETRY IN OXYGEN-ENRICHED IN-SITU COMBUSTION A Dissertation by JOSE RAMON RODRIGUEZ Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of DOCTOR...

Rodriguez, Jose Ramon

2004-09-30

16

Experimental evaluation of oxygen-enriched air and emulsified fuels in a six-cylinder diesel engine  

NASA Astrophysics Data System (ADS)

The objectives of this investigation are to (1) determine the technical feasibility of using oxygen-enriched air to increase the efficiency of and reduce emissions from diesel engines, (2) examine the effects of water-emulsified fuel on the formation of nitrogen oxides in oxygen-enriched combustion, and (3) investigate the use of lower-grade fuels in high-speed diesel engines by emulsifying the fuel with water. These tests, completed on a Caterpillar model 3406B, six-cylinder engine are a scale-up from previous, single-cylinder-engine tests. The engine was tested with (1) intake-air oxygen levels up to 30%, (2) water content up to 20% of the fuel, (3) three fuel-injection timings, and (4) three fuel-flow rates (power levels). The Taguchi technique for experimental design was used to minimize the number of experimental points in the test matrix. Four separate test matrices were run to cover two different fuel-flow-rate strategies and two different fuels (No. 2 diesel and No. 6 diesel). A liquid-oxygen tank located outside the test cell supplied the oxygen for the tests. The only modification of the engine was installation of a pressure transducer in one cylinder. All tests were run at 1800 rpm, which corresponds to the synchronous speed of a 60-Hz generator. Test results show that oxygen enrichment results in power increases of 50% or more while significantly decreasing the levels of smoke and particulates emitted. The increase in power was accompanied by a small increase in thermal efficiency. Maximum engine power was limited by the test-cell dynamometer capacity and the capacity of the fuel-injection pump. Oxygen enrichment increases nitrogen-oxide emissions significantly. No adverse effects of oxygen enrichment on the turbocharger were observed. The engine operated successfully with No. 6 fuel, but it operated at a lower thermal efficiency and emitted more smoke and particulates than with No. 2 fuel.

Sekar, R. R.; Marr, W. W.; Cole, R. L.; Marciniak, T. J.; Longman, D. E.

1993-01-01

17

Efficiency evaluation of oxygen enrichment in energy conversion processes  

Microsoft Academic Search

The extent to which energy conversion efficiencies can be increased by using oxygen or oxygen-enriched air for combustion was studied. Combustion of most fuels with oxygen instead of air was found to have five advantages: increases combustion temperature and efficiency, improves heat transfer at high temperatures, reduces nitrous oxide emissions, permits a high ration of exhaust gas recirculation and allows

Bomelburg

1983-01-01

18

Measurement of KLa by a gassing-in method with oxygen-enriched air.  

PubMed

The dynamic gassing-out method using nitrogen for gas-liquid K(L)a measurements has been modified so that gassing-out is performed with air and gassing-in with oxygen-enriched air. This new method was proven theoretically valid for use in inert model systems and in actual fermentation systems. The K(L)a values were measured in a 1-m-high bubble column and compared with those obtained from the traditional gassing-in method for three different mixing models in batchwise contacting: mixed gas and liquid (MMB); plug-flow gas and mixed liquid (PMB); and plug-flow gas and plug-flow liquid (PPB). The K(L)a values obtained from the new method were consistent with those of the method of Bartholomew et al. Discrimination between the models appeared to be not important for the 1-m-high column, but the theoretical analysis revealed that it would become necessary for columns about 10 m and higher. PMID:18588212

Chang, H N; Halard, B; Moo-Young, M

1989-11-01

19

Development of Nanofiller-Modulated Polymeric Oxygen Enrichment Membranes for Reduction of Nitrogen Oxides in Coal Combustion  

SciTech Connect

North Carolina A&T State University in Greensboro, North Carolina, has undertaken this project to develop the knowledge and the material to improve the oxygen-enrichment polymer membrane, in order to provide high-grade oxygen-enriched streams for coal combustion and gasification applications. Both experimental and theoretical approaches were used in this project. The membranes evaluated thus far include single-walled carbon nano-tube, nano-fumed silica polydimethylsiloxane (PDMS), and zeolite-modulated polyimide membranes. To document the nanofiller-modulated polymer, molecular dynamics simulations have been conducted to calculate the theoretical oxygen molecular diffusion coefficient and nitrogen molecular coefficient inside single-walled carbon nano-tube PDMS membranes, in order to predict the effect of the nano-tubes on the gas-separation permeability. The team has performed permeation and diffusion experiments using polymers with nano-silica particles, nano-tubes, and zeolites as fillers; studied the influence of nano-fillers on the self diffusion, free volume, glass transition, oxygen diffusion and solubility, and perm-selectivity of oxygen in polymer membranes; developed molecular models of single-walled carbon nano-tube and nano-fumed silica PDMS membranes, and zeolites-modulated polyimide membranes. This project partially supported three graduate students (two finished degrees and one transferred to other institution). This project has resulted in two journal publications and additional publications will be prepared in the near future.

Jianzhong Lou; Shamsuddin Ilias

2010-12-31

20

Extinguishment of methane diffusion flames by carbon dioxide in coflow air and oxygen-enriched microgravity environments  

Microsoft Academic Search

Microgravity experiments and computations have been conducted to elucidate stabilization and extinguishment mechanisms of methane diffusion flames, in the cup-burner configuration, with CO2 added gradually to a coflowing air or oxygen-enriched stream. The minimum extinguishing concentration of CO2 under low oxidizer velocities (<20 cm\\/s) was measured in microgravity achieved by parabolic flights of the NASA Reduced Gravity Aircraft. Transient computations

Fumiaki Takahashi; Gregory T. Linteris; Viswanath R. Katta

2008-01-01

21

Oxygen-enriched diesel engine performance; A comparison of analytical and experimental results  

Microsoft Academic Search

Use of oxygen-enriched combustion air in diesel can lead to significant improvements in power density, as well as reduction in particulate emissions, but at the expense of higher NOâ emissions. Oxygen enrichment would also lead to lower ignition delays and the opportunity to burn lower grade fuels. Analytical and experimental studies are being conducted in parallel to establish the optimal

R. R. Sekar; W. W. Marr; T. J. Marciniak; R. L. Cole; D. N. Assanis; J. E. Schaus

1991-01-01

22

OXYGEN-ENRICHED COAL COMBUSTION WITH CARBON DIOXIDE RECYCLE AND RECOVERY: SIMULATION AND EXPERIMENTAL STUDY  

SciTech Connect

This report examines coal combustion using oxygen feed with carbon dioxide recycle to control the adiabatic flame temperature. Computer simulations using an existing state-of-the-art 3-dimensional computer code for turbulent reacting flows with reacting particles were employed to study the effects of increased carbon dioxide mole fraction on the char burnout, radiant heat transfer, metal partitioning, and NOx formation.

John M. Veranth; Gautham Krishnamoorthy

2001-04-01

23

Carbon dioxide remediation via oxygen-enriched combustion using dense ceramic membranes  

DOEpatents

A method of combusting pulverized coal by mixing the pulverized coal and an oxidant gas to provide a pulverized coal-oxidant gas mixture and contacting the pulverized coal-oxidant gas mixture with a flame sufficiently hot to combust the mixture. An oxygen-containing gas is passed in contact with a dense ceramic membrane of metal oxide material having electron conductivity and oxygen ion conductivity that is gas-impervious until the oxygen concentration on one side of the membrane is not less than about 30% by volume. An oxidant gas with an oxygen concentration of not less than about 30% by volume and a CO.sub.2 concentration of not less than about 30% by volume and pulverized coal is contacted with a flame sufficiently hot to combust the mixture to produce heat and a flue gas. One dense ceramic membrane disclosed is selected from the group consisting of materials having formulae SrCo.sub.0.8 Fe.sub.0.2 O.sub.x, SrCo.sub.0.5 FeO.sub.x and La.sub.0.2 Sr.sub.0.8 Co.sub.0.4 Fe.sub.0.6 O.sub.x.

Balachandran, Uthamalingam (Hinsdale, IL); Bose, Arun C. (Pittsburgh, PA); McIlvried, Howard G. (Pittsburgh, PA)

2001-01-01

24

OXYGEN-ENRICHED COAL COMBUSTION WITH CARBON DIOXIDE RECYCLE AND RECOVERY: SIMULATION AND EXPERIMENTAL STUDY  

SciTech Connect

Two computational problems were worked on for this study. The first chapter examines the option of coal combustion using oxygen feed with carbon dioxide recycle to control the adiabatic flame temperature. Computer simulations using an existing state-of-the-art 3-dimensional computer code for turbulent reacting flows with reacting particles were employed to study the effects of increased carbon dioxide mole fraction on the char burnout, radiant heat transfer, metal partitioning, and NOx formation. The second chapter compares assumptions for the CO/CO{sub 2} ratio at the surface of mineral inclusions made in previous studies to predictions obtained from a pseudo-steady state kinetic model (SKIPPY) for a single porous particle. The detailed kinetic simulations from SKIPPY for varying particle sizes and bulk gas compositions were used to develop algebraic expressions for the CO/CO{sub 2} ratio that can be incorporated into metal vaporization sub-models run as a post processor to detailed furnace simulations. Vaporization rate controls the formation of metal-enriched sub-micron particles in pulverized coal fired power plants.

John M. Veranth; Gautham Krishnamoorthy

2002-02-28

25

High cell density cultivation of Pseudomonas putida KT2440 using glucose without the need for oxygen enriched air supply.  

PubMed

High Cell Density (HCD) cultivation of bacteria is essential for the majority of industrial processes to achieve high volumetric productivity (g?L(-1) h(-1) ) of a bioproduct of interest. This study developed a fed batch bioprocess using glucose as sole carbon and energy source for the HCD of the well described biocatalyst Pseudomonas putida KT2440 without the supply of oxygen enriched air. Growth kinetics data from batch fermentations were used for building a bioprocess model and designing feeding strategies. An exponential followed by linearly increasing feeding strategy of glucose was found to be effective in maintaining biomass productivity while also delaying the onset of dissolved oxygen (supplied via compressed air) limitation. A final cell dry weight (CDW) of 102?g?L(-1) was achieved in 33?h with a biomass productivity of 3.1?g?L(-1) h(-1) which are the highest ever reported values for P. putida strains using glucose without the supply of pure oxygen or oxygen enriched air. The usefulness of the biomass as a biocatalyst was demonstrated through the production of the biodegradable polymer polyhydroxyalkanoate (PHA). When nonanoic acid (NA) was supplied to the glucose grown cells of P. putida KT2440, it accumulated 32% of CDW as PHA in 11?h (2.85?g?L(-1) h(-1) ) resulting in a total of 0.56?kg of PHA in 18?L with a yield of 0.56?g PHA g NA(-1) . Biotechnol. Bioeng. 2014;9999: 1-9. © 2014 Wiley Periodicals, Inc. PMID:25311981

Davis, Reeta; Duane, Gearoid; Kenny, Shane T; Cerrone, Federico; Guzik, Maciej W; Babu, Ramesh P; Casey, Eoin; O'Connor, Kevin E

2014-10-13

26

Variable oxygen/nitrogen enriched intake air system for internal combustion engine applications  

DOEpatents

An air supply control system for selectively supplying ambient air, oxygen enriched air and nitrogen enriched air to an intake of an internal combustion engine includes an air mixing chamber that is in fluid communication with the air intake. At least a portion of the ambient air flowing to the mixing chamber is selectively diverted through a secondary path that includes a selectively permeable air separating membrane device due a differential pressure established across the air separating membrane. The permeable membrane device separates a portion of the nitrogen in the ambient air so that oxygen enriched air (permeate) and nitrogen enriched air (retentate) are produced. The oxygen enriched air and the nitrogen enriched air can be selectively supplied to the mixing chamber or expelled to atmosphere. Alternatively, a portion of the nitrogen enriched air can be supplied through another control valve to a monatomic-nitrogen plasma generator device so that atomic nitrogen produced from the nitrogen enriched air can be then injected into the exhaust of the engine. The oxygen enriched air or the nitrogen enriched air becomes mixed with the ambient air in the mixing chamber and then the mixed air is supplied to the intake of the engine. As a result, the air being supplied to the intake of the engine can be regulated with respect to the concentration of oxygen and/or nitrogen.

Poola, Ramesh B. (Woodridge, IL); Sekar, Ramanujam R. (Naperville, IL); Cole, Roger L. (Elmhurst, IL)

1997-01-01

27

Numerical investigation of influence of homogeneous\\/heterogeneous ignition\\/combustion mechanisms on ignition point position during pulverized coal combustion in oxygen enriched and recycled flue gases atmosphere  

Microsoft Academic Search

It is expected that pulverized coal combustion will continue to play a major role in electricity generation for the foreseeable future. Oxy-fuel coal combustion is actively being investigated, as alternative to conventional pulverized-coal combustion, due to its potential to easier carbon dioxide sequestration. This paper presents experimental and numerical analysis of ignition phenomena in oxy-fuel conditions. A modification of standard

Rastko Jovanovic; Aleksandra Milewska; Bartosz Swiatkowski; Adrian Goanta; Hartmut Spliethoff

2011-01-01

28

Waste to energy operability enhancement under waste uncertainty via oxygen enrichment.  

PubMed

Waste to energy (WTE) performance is evaluated by maximization of electrical energy production and throughput, while maintaining low operational costs and complying with emission limits. Uncertainty in the quantities, composition and heating values of received wastes, pose severe operability problems and impair performance and emissions. The present work demonstrates and quantifies the possibility of improving WTE efficiency under feedstock uncertainty via oxygen enrichment of the combustion air. Acting essentially as a nitrogen depletion mechanism, oxygen enrichment has reverse effects compared to excess air (EA); synergistic use provides extended capabilities for performance improvement, without impairing final emissions, while satisfying capacity constraints. Increased oxygen enrichment is required at higher EA to maintain temperature. Lower charging rates of rich wastes (plastics, paper, etc.) or diminishing heating values, require higher oxygen enrichment or lower EA. The opposite holds for lower charging rates of poor wastes (biodegradables, biosludge, inerts, etc.) or rising heating values. The results establish the possibility of nominal designs to respond to feedstock variations and may be useful for low range excess air operation (low cost) or adiabatic operation (high EA, combustor temperature controlled by large fluegas volumes). The vector formulation facilitates digital coding for applications featuring multiple waste mixture variability. A 700000 tpa WTE facility in Athens, now under public-private-partnership contract tender is investigated. PMID:25036380

Tsiliyannis, Christos Aristeides

2014-08-19

29

Effects of EGR, water/N2/CO2 injection and oxygen enrichment on the availability destroyed due to combustion for a range of conditions and fuels  

E-print Network

combustion of iso octane.................................................................................................... 24 3 Percentage availability destroyed for different ?Cooled? EGR fractions as a function of reactant temperature for constant... volume combustion of iso octane, reactant pressure of 500 kPa......................................................... 24 4 Product temperature for different ?Cooled? EGR fractions as a function of reactant temperature for constant pressure combustion...

Sivadas, Hari Shanker

2009-06-02

30

Taguchi methods applied to oxygen-enriched diesel engine experiments  

SciTech Connect

This paper describes a test series conducted on a six-cylinder diesel engine to study the impacts of controlled factors (i.e., oxygen content of the combustion air, water content of the fuel, fuel rate, and fuel-injection timing) on engine emissions using Taguchi methods. Three levels of each factor were used in the tests. Only the main effects of the factors were examined; no attempt was made to analyze the interactions among the factors. It was found that, as in the case of the single-cylinder engine tests, oxygen in the combustion air was very effective in reducing particulate and smoke emissions. Increases in NO[sub x] due to the oxygen enrichment observed in the single-cylinder tests also occurred in the present six-cylinder tests. Water in the emulsified fuel was found to be much less effective in decreasing NO[sub x] emissions for the six-cylinder engine than it was for the single-cylinder engine.

Marr, W.W.; Sekar, R.R.; Cole, R.L.; Marciniak, T.J. (Argonne National Lab., IL (United States)); Longman, D.E. (Autoresearch Labs., Inc., Chicago, IL (United States))

1992-01-01

31

Taguchi methods applied to oxygen-enriched diesel engine experiments  

SciTech Connect

This paper describes a test series conducted on a six-cylinder diesel engine to study the impacts of controlled factors (i.e., oxygen content of the combustion air, water content of the fuel, fuel rate, and fuel-injection timing) on engine emissions using Taguchi methods. Three levels of each factor were used in the tests. Only the main effects of the factors were examined; no attempt was made to analyze the interactions among the factors. It was found that, as in the case of the single-cylinder engine tests, oxygen in the combustion air was very effective in reducing particulate and smoke emissions. Increases in NO{sub x} due to the oxygen enrichment observed in the single-cylinder tests also occurred in the present six-cylinder tests. Water in the emulsified fuel was found to be much less effective in decreasing NO{sub x} emissions for the six-cylinder engine than it was for the single-cylinder engine.

Marr, W.W.; Sekar, R.R.; Cole, R.L.; Marciniak, T.J. [Argonne National Lab., IL (United States); Longman, D.E. [Autoresearch Labs., Inc., Chicago, IL (United States)

1992-12-01

32

An oxygen enrichment device for lowlanders ascending to high altitude  

PubMed Central

Background When ascending to the high altitude, people living in low altitude areas will suffer from acute mountain sickness. The aim of this study is to test the hypothesis that whether an oxygen concentration membrane can be made and used to construct a new portable oxygen enrichment device for individuals in acute exposure to the high altitude. Methods The membrane was fabricated using vinylsiloxane rubber, polyphenylene oxide hydrogen silicone polymers, chloroplatinic acid and isopropyl alcohol. The membrane was assembled in a frame and the performance was tested in terms of concentration of oxygen, flow rate of oxygen enriched air, pressure ratio across the membrane and ambient temperature. Furthermore, the oxygen concentration device was constructed using the membrane, a DC fan, vacuum pump and gas buffer. A nonrandomized preliminary field test was conducted, in which eight healthy male subjects were flown to Tibet (Lhasa, 3,700 m). First, subjects wore the oxygen enrichment device and performed an incremental exercise on cycle ergometer. The test included heart rate (HR), saturation of peripheral oxygen (SpO2) and physical work capacity (PWC). Then, after a rest period of 4 hours, the experimental protocol was repeated without oxygen enrichment device. Results The testing showed that the membrane could increase the oxygen concentration by up to 30%. Simulation test indicated that although the performance of the oxygen enrichment device decreased with altitudes, the oxygen concentration could still maintain 28% with flow rate of enriched air 110 cm3/s at 5000 m. The field test showed that higher SpO2, lower HR, and better PWC (measured by the PWC-170) were observed from all the subjects using oxygen enrichment device compared with non-using (P?oxygen enrichment device would be effective in improving exercise performance when ascending to the high altitude. PMID:24103365

2013-01-01

33

Evaluation of oxygen-enrichment system for alternative fuel vehicles  

SciTech Connect

This report presents results on the reduction in exhaust emissions achieved by using oxygen-enriched intake air on a flexible fuel vehicle (FFV) that used Indolene and M85 as test fuels. The standard federal test procedure (FTP) and the US Environmental Protection Agency`s (EPA`s) off-cycle (REP05) test were followed. The report also provides a review of literature on the oxygen membrane device and design considerations. It presents information on the sources and contributions of cold-phase emissions to the overall exhaust emissions from light-duty vehicles (LDVs) and on the various emission standards and present-day control technologies under consideration. The effects of oxygen-enriched intake air on FTP and off-cycle emissions are discussed on the basis of test results. Conclusions are drawn from the results and discussion, and different approaches for the practical application of this technology in LDVs are recommended.

Poola, R.B.; Sekar, R.R.; Ng, H.K.

1995-12-01

34

AIR EMISSIONS FROM SCRAP TIRE COMBUSTION  

EPA Science Inventory

The report discusses air emissions from two types of scrap tire combustion: uncontrolled and controlled. Uncontrolled sources are open tire fires, which produce many unhealthful products of incomplete combustion and release them directly into the atmosphere. Controlled combustion...

35

Fire extinguishment in oxygen enriched atmospheres  

NASA Technical Reports Server (NTRS)

Current state-of-the-art of fire suppression and extinguishment techniques in oxygen enriched atmosphere is reviewed. Four classes of extinguishment action are considered: cooling, separation of reactants, dilution or removal of fuel, and use of chemically reactive agents. Current practice seems to show preference for very fast acting water spray applications to all interior surfaces of earth-based chambers. In space, reliance has been placed on fire prevention methods through the removal of ignition sources and use of nonflammable materials. Recommendations are made for further work related to fire suppression and extinguishment in oxygen enriched atmospheres, and an extensive bibliography is appended.

Robertson, A. F.; Rappaport, M. W.

1973-01-01

36

Hexane Air Combustion  

E-print Network

Hot surface ignition and subsequent flame propagation of premixed n-hexane air mixtures are shown in this fluid dynamics video. High speed schlieren photography revealed 3 distinct behaviors of ignition and propagation as a function of mixture composition and initial pressure.

Boettcher, Philipp A; Shepherd, Joseph E

2010-01-01

37

Combustion Air Control  

E-print Network

-air ratio adjusted to meet the selected efficiency measure. The boiler should be lined out and operating long enough at each load level to allow temperatures to stab i 1i ze . ? A series of readings at each load level is taken and the results averaged....3 81.0 100.0 Fir Flow - FR 1013 41.2 41.2 57.7 74.4 100.0 Ratio - Apparent/Actual 1. 15 1. 03 1. 08 1. 09 1.0 O 2 Controller Out* (Sets Multiplier) 74.7 55.0 64.0 62.7 55.0 Air Flow Controller Output* 29.3 30.0 45.3 62.7 92.0 Fuel Flow - 0 i...

Hughart, C. L.

1979-01-01

38

Combustion engine with additional air inlet valve  

Microsoft Academic Search

A combustion engine equipped with an additional air-inlet means and a control arrangement for closing and opening the inlet is described that results in more efficient combustion and favorable limitation of carbon monoxide and nitrogen oxide formation. The scope of the invention covers cylindrical, lifting, or rotary piston arrangements. The additional air inlet and its associated cam controlling device allow

Gospodar

1974-01-01

39

Internal combustion engine with compound air compression  

Microsoft Academic Search

This patent describes an internal combustion engine in combination with a compound air compression system. It comprises: a reciprocator with at least one cylinder, at least one piston reciprocal in the cylinder and a combustion chamber formed in substantial part by portions of the piston and cylinder, the reciprocator having a drive shaft; a rotary compressor having a drive shaft

M. A. Paul; A. Paul

1991-01-01

40

Air cleaning means for internal combustion engine  

Microsoft Academic Search

Air cleaning means suitable for use with an internal combustion engine are disclosed that includes a fuel vapor adsorbing filter element and a sucked air cleaning filter element arranged independently of and separately from each other. The fuel vapor adsorbing filter element includes a filter material layer containing fibers of active carbon for adsorbing fuel vapors thereon, and a metallic

Y. Nakamura; Y. Yamakawa

1981-01-01

41

Combustion Air Preheat Should Be More Than Simply Recycling Energy  

E-print Network

Combustion air preheat can and should result in fuel savings far in excess of the energy added to the combustion air. In a typical installation of air preheat on a fired tubular reactor, the addition of 2.5 million BTU/hr to the combustion air...

Grantom, R. L.

1980-01-01

42

Combustion engine. [for air pollution control  

NASA Technical Reports Server (NTRS)

An arrangement for an internal combustion engine is provided in which one or more of the cylinders of the engine are used for generating hydrogen rich gases from hydrocarbon fuels, which gases are then mixed with air and injected into the remaining cylinders to be used as fuel. When heavy load conditions are encountered, hydrocarbon fuel may be mixed with the hydrogen rich gases and air and the mixture is then injected into the remaining cylinders as fuel.

Houseman, J. (inventor)

1977-01-01

43

The optimization air separation plants for combined cycle MHD-power plant applications  

NASA Technical Reports Server (NTRS)

Some of the design approaches being employed during a current supported study directed at developing an improved air separation process for the production of oxygen enriched air for magnetohydrodynamics (MHD) combustion are outlined. The ultimate objective is to arrive at conceptual designs of air separation plants, optimized for minimum specific power consumption and capital investment costs, for integration with MHD combined cycle power plants.

Juhasz, A. J.; Springmann, H.; Greenberg, R.

1980-01-01

44

Pulverised Coal Combustion Under Transient Cloud Conditions in a Drop Tube Furnace  

Microsoft Academic Search

A low volatile coal was burned with oxygen-enriched air in a drop tube furnace at 1223 and 1523 K, either as single particles or as small batches added as a pulse. The particle temperatures and burnout times at the two furnace temperatures were recorded for each test. The ignition \\/ combustion processes were recorded by pyrometer and video camera. The

B. R. STANMORE; Y.-C. CHOI; R. GADIOU; O. CHARON; P. GILOT

2000-01-01

45

High-Efficiency Low-Dross Combustion System for Aluminum Remelting Reverberatory Furnaces, Project Final Report, July 2005  

Microsoft Academic Search

GTI, and its commercial partners, have developed a high-efficiency low-dross combustion system that offers environmental and energy efficiency benefits at lower capital costs for the secondary aluminum industry users of reverberatory furnaces. The high-efficiency low-dross combustion system, also called Self-Optimizing Combustion System (SOCS), includes the flex-flame burner firing an air or oxygen-enriched natural gas flame, a non-contact optical flame sensor,

V. Soupos; S. Zelepouga; D. Rue

2005-01-01

46

External combustion engine with air-supported free piston  

Microsoft Academic Search

An external combustion engine is described comprising: a combustion member including a sleeve having an end closure and an ignition means at each end thereof, inlet and outlet valving means for introducing compressed air and exhausting combusted gases through valving openings, and a free piston mounted in the sleeve for sliding reciprocating axial motion between the end closures and defining

1987-01-01

47

Emission Controls Using Different Temperatures of Combustion Air  

PubMed Central

The effort of many manufacturers of heat sources is to achieve the maximum efficiency of energy transformation chemically bound in the fuel to heat. Therefore, it is necessary to streamline the combustion process and minimize the formation of emission during combustion. The paper presents an analysis of the combustion air temperature to the heat performance and emission parameters of burning biomass. In the second part of the paper the impact of different dendromass on formation of emissions in small heat source is evaluated. The measured results show that the regulation of the temperature of the combustion air has an effect on concentration of emissions from the combustion of biomass. PMID:24971376

Holub?ík, Michal; Papu?ík, Štefan

2014-01-01

48

Basic Considerations in the Combustion of Hydrocarbon Fuels with Air  

NASA Technical Reports Server (NTRS)

Basic combustion research is collected, collated, and interpreted as it applies to flight propulsion. The following fundamental processes are treated in separate chapters: atomization and evaporation of liquid fuels, flow and mixing processes in combustion chambers, ignition and flammability of hydrocarbon fuels, laminar flame propagation, turbulent flames, flame stabilization, diffusion flames, oscillations in combustors, and smoke and coke formation in the combustion of hydrocarbon-air mixtures. Theoretical background, basic experimental data, and practical significance to flight propulsion are presented.

Barnett, Henry C; Hibbard, Robert R

1957-01-01

49

Air\\/fuel ratio sensor for an internal combustion engine  

Microsoft Academic Search

A sensor is described for detecting the air\\/fuel ratio of the exhaust gas from an internal combustion engine comprising: a housing, said housing defining a closed air chamber, said air chamber being fluidly sealed from the exhaust gas, an oxygen diffusion cell constructed of an electrolytic material, said diffusion cell having one side exposed to the exhaust gas and a

Hunt

1993-01-01

50

CFD Simulation of High Temperature Air Combustion of Coal Gas at Different Air Straddle Angle  

Microsoft Academic Search

Numerical simulation was carried out on the High Temperature Air Combustion of coal gas in an industrial furnace with a multi-jet burner. A Beta-function PDF (Probability Density Function) combustion model was selected to simulate the gas combustion combined with the standard k-? turbulent model. The radiation was simulated by a Discrete Ordinates method. Thermal NOx model was used to calculate

Yaxin Su; Bingtao Zhao

2010-01-01

51

Combustion Safety for Appliances Using Indoor Air (Fact Sheet)  

SciTech Connect

This measure guideline covers how to assess and carry out the combustion safety procedures for appliances and heating equipment that uses indoor air for combustion in low-rise residential buildings. Only appliances installed in the living space, or in an area freely communicating with the living space, vented alone or in tandem with another appliance are considered here. A separate measure guideline addresses combustion appliances located either within the living space in enclosed closets or side rooms or outside the living space in an adjacent area like an attic or garage that use outdoor air for combustion. This document is for inspectors, auditors, and technicians working in homes where energy upgrades are being conducted whether or not air infiltration control is included in the package of measures being applied. In the indoor combustion air case, guidelines summarized here are based on language provided in several of the codes to establish minimum requirements for the space using simplified prescriptive measures. In addition, building performance testing procedures are provided by testing agencies. The codes in combination with the test procedures offer comprehensive combustion safety coverage to address safety concerns, allowing inexperienced residential energy retrofit inspectors to effectively address combustion safety issues and allow energy retrofits to proceed.

Not Available

2014-05-01

52

Dependence the amount of combustion air and its redistribution to primary and secondary combustion air and his depending on the boiler  

NASA Astrophysics Data System (ADS)

The production of solid pollutants is affected by several influences. The amount of combustion air and its redistribution to primary and secondary combustion air. The experimental device, what which has been examined the amount of the combustion air on the production of the solid pollutants, methods of measurement, measurements results and analysis of the results obtained will be described in the papers.

Papu?ík, Štefan; Lenhard, Richard; Kaduchová, Katarína; Janda?ka, Jozef; Koloni?ný, Jan; Horák, Ji?í

2014-08-01

53

BIBLIOGRAPHY ON INTERNAL COMBUSTION ENGINES 1. F. Obert, Internal Combustion Engines and Air Pollution, Intext Educational Publishers, 1973  

E-print Network

BIBLIOGRAPHY ON INTERNAL COMBUSTION ENGINES 1. F. Obert, Internal Combustion Engines and Air, The Internal Combustion Engine, International Textbook Company, 1961. (A basic text now out of print and somewhat dated.) 3. C.F. Taylor, The Internal Combustion Engine in Theory and Practice. Volumes I and II, M

Goldwasser, Shafi

54

Catalytic Igniter to Support Combustion of Ethanol-Water\\/Air Mixtures in Internal Combustion Engines  

Microsoft Academic Search

Lean ethanol-water\\/air mixtures have potential for reducing NOx and CO emissions in internal combustion engines. Igniting such mixtures is not possible with conventional ignition sources. An improved catalytic ignition source is being developed to aid in the combustion of aqueous ethanol. The operating principle is homogeneous charge compression ignition in a catalytic pre-chamber, followed by torch ignition of the main

Dan Cordon; Eric Clarke; Steven Beyerlein; Judi Steciak

55

Closed loop air cooling system for combustion turbines  

DOEpatents

Convective cooling of turbine hot parts using a closed loop system is disclosed. Preferably, the present invention is applied to cooling the hot parts of combustion turbine power plants, and the cooling provided permits an increase in the inlet temperature and the concomitant benefits of increased efficiency and output. In preferred embodiments, methods and apparatus are disclosed wherein air is removed from the combustion turbine compressor and delivered to passages internal to one or more of a combustor and turbine hot parts. The air cools the combustor and turbine hot parts via convection and heat is transferred through the surfaces of the combustor and turbine hot parts. 1 fig.

Huber, D.J.; Briesch, M.S.

1998-07-21

56

Closed loop air cooling system for combustion turbines  

DOEpatents

Convective cooling of turbine hot parts using a closed loop system is disclosed. Preferably, the present invention is applied to cooling the hot parts of combustion turbine power plants, and the cooling provided permits an increase in the inlet temperature and the concomitant benefits of increased efficiency and output. In preferred embodiments, methods and apparatus are disclosed wherein air is removed from the combustion turbine compressor and delivered to passages internal to one or more of a combustor and turbine hot parts. The air cools the combustor and turbine hot parts via convection and heat is transferred through the surfaces of the combustor and turbine hot parts.

Huber, David John (North Canton, OH); Briesch, Michael Scot (Orlando, FL)

1998-01-01

57

CFD Modeling of Oxygen-Enriched, Turbulent, Non-Premixed Flames: Interactions Among Turbulence, Soot Formation\\/Oxidation, and Thermal Radiation  

Microsoft Academic Search

The use of oxygen-enriched air as an oxidizer offers advantages including fuel savings and reduced NOx emissions in some applications. Turbulence, soot formation\\/oxidation, and thermal radiation interact strongly to establish the overall flame structure and pollutant emissions in such flames. A comprehensive CFD-based model including detailed hydrocarbon-air and NOx chemistry, detailed soot modeling, and thermal radiation (P1 approximation for the

Liangyu Wang; Daniel C. Haworth; Stephen R. Turns

2003-01-01

58

Air or air and fuel mixture flow control in valve controlled internal combustion engines  

Microsoft Academic Search

In order to provide a controlled turbulence or angular momentum of air, air and fuel mixtures or similar fluids to be injected into the cylinder chamber of valve controlled internal combustion engines, control vanes are provided in close proximity to the valve retaining ring. The vanes deflect the flow of the air\\/fuel mixture without restricting the flow thus increasing the

1979-01-01

59

Combustion performance evaluation of air staging of palm oil blends.  

PubMed

The problems of global warming and the unstable price of petroleum oils have led to a race to develop environmentally friendly biofuels, such as palm oil or ethanol derived from corn and sugar cane. Biofuels are a potential replacement for fossil fuel, since they are renewable and environmentally friendly. This paper evaluates the combustion performance and emission characteristics of Refined, Bleached, and Deodorized Palm Oil (RBDPO)/diesel blends B5, B10, B15, B20, and B25 by volume, using an industrial oil burner with and without secondary air. Wall temperature profiles along the combustion chamber axis were measured using a series of thermocouples fitted axially on the combustion chamber wall, and emissions released were measured using a gas analyzer. The results show that RBDPO blend B25 produced the maximum emission reduction of 56.9% of CO, 74.7% of NOx, 68.5% of SO(2), and 77.5% of UHC compared to petroleum diesel, while air staging (secondary air) in most cases reduces the emissions further. However, increasing concentrations of RBDPO in the blends also reduced the energy released from the combustion. The maximum wall temperature reduction was 62.7% for B25 at the exit of the combustion chamber. PMID:22296110

Mohd Jaafar, Mohammad Nazri; Eldrainy, Yehia A; Mat Ali, Muhammad Faiser; Wan Omar, W Z; Mohd Hizam, Mohd Faizi Arif

2012-02-21

60

Indoor air quality environmental information handbook: Combustion sources  

SciTech Connect

This environmental information handbook was prepared to assist both the non-technical reader (i.e., homeowner) and technical persons (such as researchers, policy analysts, and builders/designers) in understanding the current state of knowledge regarding combustion sources of indoor air pollution. Quantitative and descriptive data addressing the emissions, indoor concentrations, factors influencing indoor concentrations, and health effects of combustion-generated pollutants are provided. In addition, a review of the models, controls, and standards applicable to indoor air pollution from combustion sources is presented. The emphasis is on the residential environment. The data presented here have been compiled from government and privately-funded research results, conference proceedings, technical journals, and recent publications. It is intended to provide the technical reader with a comprehensive overview and reference source on the major indoor air quality aspects relating to indoor combustion activities, including tobacco smoking. In addition, techniques for determining potential concentrations of pollutants in residential settings are presented. This is an update of a 1985 study documenting the state of knowledge of combustion-generated pollutants in the indoor environment. 191 refs., 51 figs., 71 tabs.

Not Available

1990-06-01

61

75 FR 80761 - National Emission Standards for Hazardous Air Pollutants for Reciprocating Internal Combustion...  

Federal Register 2010, 2011, 2012, 2013, 2014

...for Hazardous Air Pollutants for Reciprocating Internal Combustion Engines AGENCY: Environmental Protection Agency (EPA...for hazardous air pollutants for reciprocating internal combustion engines and requesting public comment on one issue...

2010-12-23

62

Effect of Combustion Air Preheat on a Forged Furnace Productivity  

E-print Network

A basic thermal analysis of a gas fired forge furnace can determine the fuel savings from exhaust energy recovery/combustion air preheat on a furnace operating at a single condition, for example, high fire. What this analysis is not able...

Ward, M. E.; Bohn, J.; Davis, S. R.; Knowles, D.

1984-01-01

63

REFINERY PROCESS HEATER NOX CONTROL BY STAGED COMBUSTION AIR LANCES  

EPA Science Inventory

The paper gives results of tests of a natural-draft petroleum-refinery crude-oil process heater, modified to reduce oxides of nitrogen (NOx) emissions by installing staged-combustion air lances. Baseline nitric oxide (NO) emissions firing refinery gas before modification were mea...

64

Oxygen Enrichment in the Process and Chemical Industries  

E-print Network

an air oxidation step (Table 1). Some Organic Intermediates Produced by Air Oxidation: ? Adipic Acid ? Acetaldehyde ? Acetic Acid ? Acrylonitrile ? Acrylic Acid ? Acetone ? Ethylene Oxide ? Formaldehyde ? Maleic Anhydride ? Phenol... ? Phthallic Anhydride ? Propylene Oxide TABLE 1 \\-Jith the national economy showing signs of s rong improvement, it is fel t that there may be si ua tions in which the use of oxygen or oxygen-e riched air as a means of debottlenecking an air-bas d plant...

Milne, R. T.

1984-01-01

65

Secondary air systems for improved residential wood stove combustion  

SciTech Connect

Three wood burning stoves were modified by the addition of preheated secondary air systems to keep burn volatile gases given off during the initial stage of combustion. This report describes the modifications and the performance of the stoves after modification. Stoves tested during the year's study included a Jotul 118, a Garrison IV and a Hearthstone I. After modification, total particulate emissions decreased in the three stoves by 56%, 69% and 4%, respectively. Flue gas CO/sub 2/ (a by-product of combustion and an indicator of the completeness of combustion) increased by 15%, 15% and 17%, respectively. Temperatures in the secondary combustion zones increased by 17%, 50% and 6%. On the basis of these measurements, other internal temperatures and visual observations, we believe the modifications significantly increased the combustion efficiencies of the Jotul and the Garrison. No improvement was discerned in the Hearthstone's performance (possibly due to unrealistic burn rate compared to firebox size). The design concepts developed, refined and tested under this year's study should be readily applicable to the majority of residential wood stoves on the market.

Poirot, R.L.; Sanborn, C.R.

1982-12-21

66

Internal combustion engine air intake system with variable effective length  

SciTech Connect

An air intake system for feeding intake air to combustion chambers of a multicylinder internal combustion engine having two groups of longitudinally spaced engine cylinders is described comprising: a. a longitudinally extending surge tank positioned adjacent the engine cylinders; b. flow control valve means for opening and closing the aperture, the flow control valve means including a butterfly valve pivotally mounted in the aperture of the wall extension of the extension portion; and c. actuator means responsive to engine operating conditions for controlling opening and closing of the butterfly valve to vary the extent of flow communication between the volumetric chambers through the aperture, thereby varying the effective length of the intake system with engine operating conditions.

Wada, H.; Horio, K.; Abe, K.

1988-04-19

67

Combustion of olive cake and coal in a bubbling fluidized bed with secondary air injection  

Microsoft Academic Search

Combustion performances and emission characteristics of olive cake and coal are investigated in a bubbling fluidized bed. Flue gas concentrations of O2, CO, SO2, NOx, and total hydrocarbons (CmHn) were measured during combustion experiments. Operational parameters (excess air ratio (?), secondary air injection) were changed and variation of pollutant concentrations and combustion efficiency with these operational parameters were studied. The

Murat Varol; Aysel T. Atimtay

2007-01-01

68

Combustion of stratified hydrogen-air mixtures in the 10.7 m 3 combustion test facility cylinder  

Microsoft Academic Search

This paper presents preliminary results from hydrogen concentration gradient combustion experiments in a 10.7 m3 cylinder. These gradients, also referred to as stratified mixtures, were formed from dry mixtures of hydrogen and air at atmospheric temperature. Combustion pressures, burn fractions and flame speeds in concentration gradients were compared with combustion of well-mixed gases containing equivalent amounts of hydrogen. The studied

D. R. Whitehouse; D. R. Greig; G. W. Koroll

1996-01-01

69

Experimental and Numerical Studies on Methane\\/Air Combustion in a Micro Swiss-Roll Combustor  

Microsoft Academic Search

To understand effects of an air groove on working characteristics of micro Swiss-roll combustors, combustion of premixed CH4\\/air is conducted in 2 micro Swiss-roll combustors, one with an air groove and the other without. Experimental results show that stable combustion of premixed CH4\\/air in 2 combustors can be achieved and the flame is kept in combustor's center. An air groove

Junwei Li; Beijing Zhong; Ningfei Wang; Zhijun Wei

2010-01-01

70

Atmospheric pressure fluctuations and oxygen enrichment in waste tanks  

SciTech Connect

During In-Tank Precipitation (ITP) processing radiolytic decomposition of tetraphenylborate and water can produce benzene and hydrogen, which, given sufficiently high oxygen concentrations, can deflagrate. To prevent accumulations of benzene and hydrogen and avoid deflagration, continuous nitrogen purging is maintained. If the nitrogen purging is interrupted by, for example, a power failure, outside air will begin to seep into the tank through vent holes and cracks. Eventually a flammable mixture of benzene, hydrogen, and oxygen will occur (deflagration). However, this process is slow under steady-state conditions (constant pressure) and mechanisms to increase the exchange rate with the outside atmosphere must be considered. The most important mechanism of this kind is from atmospheric pressure fluctuations in which an increase in atmospheric pressure forces air into the tank which then mixes with the hydrogen-benzene mixture. The subsequent decrease in atmospheric pressure causes venting from the tank of the mixture -- the net effect being an increase in the tank`s oxygen concentration. Thus, enrichment occurs when the atmospheric pressure increases but not when the pressure decreases. Moreover, this natural atmospheric {open_quotes}pumping{close_quotes} is only important if the pressure fluctuations take place on a time scale longer than the characteristic mixing time scale (CMT) of the tank. If pressure fluctuations have a significantly higher frequency than the CMT, outside air will be forced into the tank and then out again before any significant mixing can occur. The CMT is not known for certain, but is estimated to be between 8 and 24 hours. The purpose of this report is to analyze yearly pressure fluctuations for a five year period to determine their statistical properties over 8 and 24-hour periods. The analysis also includes a special breakdown into summer and winter seasons and an analysis of 15-minute data from the SRTC Climatology Site.

Kurzeja, R.J.; Weber, A.H.

1993-07-01

71

Soot filter in the exhaust gas flow of air-compressing internal combustion engines  

Microsoft Academic Search

A soot filter adapted to be arranged in an exhaust gas stream of air-compressing internal combustion engines is disclosed. The soot filter includes a cylindrical filter housing arranged in proximity of the exhaust gas stream of the internal combustion engine with inlet pipe connecting studs from outlet side of the internal combustion engine being connected to the cylindrical filter housing.

J. Abthoff; R. Gabler; H. Schuster

1980-01-01

72

Future Directions of Supersonic Combustion Research: Air Force/NASA Workshop on Supersonic Combustion  

NASA Technical Reports Server (NTRS)

The Air Force Office of Scientific Research, the Air Force Wright Laboratory Aero Propulsion and Power Directorate, and the NASA Langley Research Center held a joint supersonic combustion workshop on 14-16 May 1996. The intent of this meeting was to: (1) examine the current state-of-the-art in hydrocarbon and/or hydrogen fueled scramjet research; (2) define the future direction and needs of basic research in support of scramjet technology; and (3) when appropriate, help transition basic research findings to solve the needs of developmental engineering programs in the area of supersonic combustion and fuels. A series of topical sessions were planned. Opening presentations were designed to focus and encourage group discussion and scientific exchange. The last half-day of the workshop was set aside for group discussion of the issues that were raised during the meeting for defining future research opportunities and directions. The following text attempts to summarize the discussions that took place at the workshop.

Tishkoff, Julian M.; Drummond, J. Philip; Edwards, Tim; Nejad, Abdollah S.

1997-01-01

73

Effect of air-staging on anthracite combustion and NOx formation  

SciTech Connect

Experiments were carried out in a multipath air inlet one-dimensional furnace to assess NOx emission characteristics of the staged combustion of anthracite coal. These experiments allowed us to study the impact of pulverized coal fineness and burnout air position on emission under both deep and shallow air-staged combustion conditions. We also studied the impact of char-nitrogen release on both the burning-out process of the pulverized coal and the corresponding carbon content in fly ash. We found that air-staged combustion affects a pronounced reduction in NOx emissions from the combustion of anthracite coal. The more the air is staged, the more NOx emission is reduced. In shallow air-staged combustion (f{sub M} = 0.85), the fineness of the pulverized coal strongly influences emissions, and finer coals result in lower emissions. Meanwhile, the burnout air position has only a weak effect. In the deep air-staged combustion (f{sub M} = 0.6), the effect of coal fineness is smaller, and the burnout air position has a stronger effect. When the primary combustion air is stable, NOx emissions increase with increasing burnout air. This proves that, in the burnout zone, coal char is responsible for the discharge of fuel-nitrogen that is oxidized to NOx. The measurement of secondary air staging in a burnout zone can help inhibit the oxidization of NO caused by nitrogen release. Air-staged combustion has little effect on the burnout of anthracite coal, which proves to be suitable for air-staged combustion. 31 refs., 11 figs., 1 tab.

Weidong Fan; Zhengchun Lin; Youyi Li; Jinguo Kuang; Mingchuan Zhang [Shanghai Jiao Tong University, Shanghai (China). School of Mechanical & Power Engineering

2009-01-15

74

Development of high temperature air combustion technology in pulverized fossil fuel fired boilers  

Microsoft Academic Search

High temperature air combustion (HTAC) is a promising technology for energy saving, flame stability enhancement and NOx emission reduction. In a conventional HTAC system, the combustion air is highly preheated by using the recuperative or regenerative heat exchangers. However, such a preheating process is difficult to implement for pulverized fossil fuel fired boilers. In this paper, an alternative approach is

Hai Zhang; Guangxi Yue; Junfu Lu; Zhen Jia; Jiangxiong Mao; Toshiro Fujimori; Toshiyuki Suko; Takashi Kiga

2007-01-01

75

Investigation of Ignition and Combustion Processes of Diesel Engines Operating with Turbulence and Air-storage Chambers  

NASA Technical Reports Server (NTRS)

The flame photographs obtained with combustion-chamber models of engines operating respectively, with turbulence chamber and air-storage chambers or cells, provide an insight into the air and fuel movements that take place before and during combustion in the combustion chamber. The relation between air velocity, start of injection, and time of combustion was determined for the combustion process employing a turbulence chamber.

Petersen, Hans

1938-01-01

76

The Influence of Directed Air Flow on Combustion in Spark-Ignition Engine  

NASA Technical Reports Server (NTRS)

The air movement within the cylinder of the NACA combustion apparatus was regulated by using shrouded inlet valves and by fairing the inlet passage. Rates of combustion were determined at different inlet-air velocities with the engine speed maintained constant and at different engine speeds with the inlet-air velocity maintained approximately constant. The rate of combustion increased when the engine speed was doubled without changing the inlet-air velocity; the observed increase was about the same as the increase in the rate of combustion obtained by doubling the inlet-air velocity without changing the engine speed. Certain types of directed air movement gave great improvement in the reproducibility of the explosions from cycle to cycle, provided that other variables were controlled. Directing the inlet air past the injection valve during injection increased the rate of burning.

Rothrock, A M; Spencer, R C

1939-01-01

77

Combustion Air Preheat and Radiant Heat Transfer in Fired Heaters - A Graphical Method for Design and Operating Analysis  

E-print Network

The installation of combustion air preheat is a widely used technique for improving the fuel efficiency of existing fired heaters and fired tubular reactors. By increasing adiabatic flame temperature, combustion air preheat increases radiant section...

Grantom, R. L.

1981-01-01

78

Preliminary analysis of an improved external combustion hot air power system  

SciTech Connect

A novel open cycle, external combustion power system is described. It is characterized by an isothermal, expansion as in classical Ericsson and Stirling cycles, by thermally enhanced combustion and by recuperation. One mechanical embodiment of the proposed hot air system is a hot air turbine power system with external combustion. Analysis predicts the variation of specific work and efficiency as a function of the compression ratio and temperature of the isothermal expansion. The basic heat transfer problem, which is characteristic of all external combustion systems, is identified and analyzed. Specific opportunities for heat transfer enhancement are described and feasibility is demonstrated.

Fineblum, S.S. [Available Energy Co., Rochester, NY (United States)

1995-12-31

79

APTI (Air Pollution Training Institute) Course 427: combustion evaluation, student manual  

SciTech Connect

This Student Manual is used in conjunction with Course No. 427, 'Combustion Evaluation' as applied to air pollution control situations. This manual was prepared by the EPA Air Pollution Training Institute (APTI) to supplement the course lecture materials and to present detailed reference information on the following topics: combustion fundamentals, fuel properties, combustion system design, pollutant emission evaluations, combustion control, gas, oil, and coal burning, solid waste and wood burning, incineration of wastes, sewage sludge incineration, waste gas flares, hazardous waste combustion, NOx control, and improved combustion systems. Note: There is also an Instructor's Guide to be used in conducting the training course - (EPA-450/2-80-065) and a Student Workbook to be used for homework and in-class problem solving - (EPA-450/2-80-64).

Beard, J.T.; Iachetta, F.A.; Lilleleht, L.U.

1980-02-01

80

APTI (Air Pollution Training Institute) course 427: combustion evaluation, instructor's guide  

SciTech Connect

This Instructor's Guide is used in conjunction with Course No. 427, 'Combustion Evaluation' as applied to air pollution control situations. The teaching guide was prepared by the EPA Air Pollution Training Institute (APTI) to assist instructors in presenting course No. 427. The guide contains sections on the following topics: combustion fundamentals, fuel properties, combustion system design, pollutant emission calculations, combustion control, gas, oil, and burning, solid waste and wood burning, incineration of wastes, sewage sludge incineration, flame and catalytic incineration, waste gas flares, hazardous waste combustion, NOx control, improved combustion systems. Note: There is also a Student Workbook to be used for homework and in-class problem solving (EPA-450/2-80-064) and a Student Manual for reference and additional subject material (EPA-450/2-80-063).

Beard, J.T.; Iachetta, F.A.; Lilleleht, L.U.

1980-02-01

81

Thermodynamic, transport, and flow properties of gaseous products resulting from combustion of methane-air-oxygen  

NASA Technical Reports Server (NTRS)

Results of calculations to determine thermodynamic, transport, and flow properties of combustion product gases are presented. The product gases are those resulting from combustion of methane-air-oxygen and methane-oxygen mixtures. The oxygen content of products resulting from the combustion of methane-air-oxygen mixtures was similiar to that of air; however, the oxygen contained in products of methane-oxygen combustion ranged from 20 percent by volume to zero for stoichiometric combustion. Calculations were made for products of reactant mixtures with fuel percentages, by mass, of 7.5 to 20. Results are presented for specific mixtures for a range of pressures varying from 0.0001 to 1,000 atm and for temperatures ranging from 200 to 3,800 K.

Klich, G. F.

1976-01-01

82

Test methods for determining the suitability of metal alloys for use in oxygen-enriched environments  

NASA Technical Reports Server (NTRS)

Materials are more flammable in oxygen rich environments than in air. When the structural elements of a system containing oxygen ignite and burn, the results are often catastrophic, causing loss of equipment and perhaps even human lives. Therefore, selection of the proper metallic and non-metallic materials for use in oxygen systems is extremely important. While test methods for the selection of non-metallic materials have been available for years, test methods for the selection of alloys have not been available until recently. Presented here are several test methods that were developed recently at NASA's White Sands Test Facility (WSTF) to study the ignition and combustion of alloys, including the supersonic and subsonic speed particle impact tests, the frictional heating and coefficient of friction tests, and the promoted combustion test. These test methods are available for commercial use.

Stoltzfus, Joel M.; Gunaji, Mohan V.

1991-01-01

83

Estimation of Fuel Savings by Recuperation of Furnace Exhausts to Preheat Combustion Air  

E-print Network

The recovery of waste energy in furnace exhaust gases is gaining in importance as fuel costs continue to escalate. Installation of a recuperator in the furnace exhaust stream to preheat the combustion air can result in considerable savings in fuel...

Rebello, W. J.; Kohnken, K. H.; Phipps, H. R., Jr.

1980-01-01

84

Experimental investigation of wood combustion in a fixed bed with hot air  

SciTech Connect

Highlights: • Upward combustion is a new combustion concept with ignition by hot primary air. • Upward combustion has three stages: short drying, rapid devolatilization and char combustion. • Variation of fuel moisture and inert content have little influence on the combustion. • Experimental comparison between conventional and upward combustion is presented. - Abstract: Waste combustion on a grate with energy recovery is an important pillar of municipal solid waste (MSW) management in the Netherlands. In MSW incinerators fresh waste stacked on a grate enters the combustion chamber, heats up by radiation from the flame above the layer and ignition occurs. Typically, the reaction zone starts at the top of the waste layer and propagates downwards, producing heat for drying and devolatilization of the fresh waste below it until the ignition front reaches the grate. The control of this process is mainly based on empiricism. MSW is a highly inhomogeneous fuel with continuous fluctuating moisture content, heating value and chemical composition. The resulting process fluctuations may cause process control difficulties, fouling and corrosion issues, extra maintenance, and unplanned stops. In the new concept the fuel layer is ignited by means of preheated air (T > 220 °C) from below without any external ignition source. As a result a combustion front will be formed close to the grate and will propagate upwards. That is why this approach is denoted by upward combustion. Experimental research has been carried out in a batch reactor with height of 4.55 m, an inner diameter of 200 mm and a fuel layer height up to 1 m. Due to a high quality two-layer insulation adiabatic conditions can be assumed. The primary air can be preheated up to 350 °C, and the secondary air is distributed via nozzles above the waste layer. During the experiments, temperatures along the height of the reactor, gas composition and total weight decrease are continuously monitored. The influence of the primary air speed, fuel moisture and inert content on the combustion characteristics (ignition rate, combustion rate, ignition front speed and temperature of the reaction zone) is evaluated. The upward combustion concept decouples the drying, devolatilization and burnout phase. In this way the moisture and inert content of the waste have almost no influence on the combustion process. In this paper an experimental comparison between conventional and reversed combustion is presented.

Markovic, Miladin, E-mail: m.markovic@utwente.nl; Bramer, Eddy A.; Brem, Gerrit

2014-01-15

85

Burning of CP Titanium (Grade 2) in Oxygen-Enriched Atmospheres  

NASA Technical Reports Server (NTRS)

The flammability in oxygen-enriched atmospheres of commercially pure (CP) titanium rods as a function of diameter and test gas pressure was determined. Test samples of varying diameters were ignited at the bottom and burned upward in 70% O2/balance N2 and in 99.5+% O2 at various pressures. The burning rate of each ignited sample was determined by observing the apparent regression rate of the melting interface (RRMI) of the burning samples. The burning rate or RRMI increased with decreasing test sample diameter and with increasing test gas pressure and oxygen concentration

Stoltzfus, Joel M.; Jeffers, Nathan; Gallus, Timothy D.

2012-01-01

86

The effect of protein oxidation on hydration and water-binding in pork packaged in an oxygen-enriched atmosphere.  

PubMed

This study investigated the in situ oxidative process of myofibrillar proteins in boneless pork loin chops (Longissimus lumborum) packaged in an oxygen-enriched atmosphere (HiOx: 80% O2/20% CO2), an air-permeable polyvinylchloride (PVC) overwrap, or a partial vacuum (VP) throughout display at 2°C for up to 14, 7, and 21days, respectively. Samples stored in HiOx were susceptible to lipid (TBARS) and protein (carbonyls, sulfhydryls, and aggregation) oxidation, while samples in PVC and VP showed lesser oxidative changes. Water-holding capacity of raw muscle decreased (P<0.05) when stored in HiOx but not in PVC and VP. Upon salt and phosphate brine marination, HiOx and PVC muscle samples had improved hydration capacity during display compared with non-stored control, but display generally decreased hydration of VP samples. The result was in agreement with myofibril structural changes. Despite the enhanced hydration, HiOx muscle was least capable of withholding moisture upon cooking. PMID:24583326

Delles, Rebecca M; Xiong, Youling L

2014-06-01

87

Measure Guideline: Combustion Safety for Natural Draft Appliances Using Indoor Air  

SciTech Connect

This measure guideline covers how to assess and carry out the combustion safety procedures for appliances and heating equipment that uses indoor air for combustion in low-rise residential buildings. Only appliances installed in the living space, or in an area freely communicating with the living space, vented alone or in tandem with another appliance are considered here. A separate measure guideline addresses combustion appliances located either within the living space in enclosed closets or side rooms or outside the living space in an adjacent area like an attic or garage that use outdoor air for combustion. This document is for inspectors, auditors, and technicians working in homes where energy upgrades are being conducted whether or not air infiltration control is included in the package of measures being applied. In the indoor combustion air case, guidelines summarized here are based on language provided in several of the codes to establish minimum requirements for the space using simplified prescriptive measures. In addition, building performance testing procedures are provided by testing agencies. The codes in combination with the test procedures offer comprehensive combustion safety coverage to address safety concerns, allowing inexperienced residential energy retrofit inspectors to effectively address combustion safety issues and allow energy retrofits to proceed.

Brand, L.

2014-04-01

88

Hysteresis of methane inverse diffusion flames with co-flowing air and combustion products  

Microsoft Academic Search

Non-premixed flames of methane in co-flowing air and co-flowing combustion products from a lean, premixed, burner-stabilized, methane-air flame are studied with an additional central air flow, creating a double-flame structure. As the central air velocity is increased, a partially-premixed flame forms on the centreline. The height of this flame is found to be linear with the central fuel velocity, and

Michael B. Johnson; Andrzej Sobiesiak

2011-01-01

89

Suppression of premixed combustion dynamics utilizing microjet air injection  

E-print Network

The problem of thermoacoustic instability in continuous combustion systems is a major challenge in the field of propulsion and power generation. With the current environmental and political pressure that is being placed ...

Hudgins, Duane Edward

2008-01-01

90

REFINERY PROCESS HEATER NOX REDUCTIONS USING STAGED COMBUSTION AIR LANCES  

EPA Science Inventory

The report gives results of full scale tests to evaluate combustion modifications for emission control and efficiency enhancement on petroleum process heaters. Test objectives were to determine NOx emission reductions, thermal efficiency changes, long-term performance, and cost o...

91

Waste combustion as a source of ambient air polybrominated diphenylesters (PBDEs)  

EPA Science Inventory

The first comprehensive set of U.S. data on PBDE concentrations from waste combustion, with more than 40 BDE congeners reported, was compared to ambient air levels of bromodiphenylethers in the U.S. Concentrations of PBDEs were determined in the raw, pre-air pollution control sys...

92

Development of high temperature air combustion technology in pulverized fossil fuel fired boilers  

SciTech Connect

High temperature air combustion (HTAC) is a promising technology for energy saving, flame stability enhancement and NOx emission reduction. In a conventional HTAC system, the combustion air is highly preheated by using the recuperative or regenerative heat exchangers. However, such a preheating process is difficult to implement for pulverized fossil fuel fired boilers. In this paper, an alternative approach is proposed. In the proposed HTAC system, a special burner, named PRP burner is introduced to fulfill the preheating process. The PRP burner has a preheating chamber with one end connected with the primary air and the other end opened to the furnace. Inside the chamber, gas recirculation is effectively established such that hot flue gases in the furnace can be introduced. Combustible mixture instead of combustion air is highly preheated by the PRP burner. A series of experiments have been conducted in an industrial scale test facility, burning low volatile petroleum coke and an anthracite coal. Stable combustion was established for burning pure petroleum coke and anthracite coal, respectively. Inside the preheating chamber, the combustible mixture was rapidly heated up to a high temperature level close to that of the hot secondary air used in the conventional HTAC system. The rapid heating of the combustible mixture in the chamber facilitates pyrolysis, volatile matter release processes for the fuel particles, suppressing ignition delay and enhancing combustion stability. Moreover, compared with the results measured in the same facility but with a conventional low NOx burner, NOx concentration at the furnace exit was at the same level when petroleum coke was burnt and 50% less when anthracite was burnt. Practicability of the HTAC technology using the proposed approach was confirmed for efficiently and cleanly burning fossil fuels. 16 refs., 10 figs., 1 tab.

Hai Zhang; Guangxi Yue; Junfu Lu; Zhen Jia; Jiangxiong Mao; Toshiro Fujimori; Toshiyuki Suko; Takashi Kiga [Tsinghua University, Beijing (China). Department of Thermal Engineering

2007-07-01

93

Combustion Velocity of Benzine-Benzol-Air Mixtures in High-Speed Internal-Combustion Engines  

NASA Technical Reports Server (NTRS)

The present paper describes a device whereby rapid flame movement within an internal-combustion engine cylinder may be recorded and determined. By the aid of a simple cylindrical contact and an oscillograph the rate of combustion within the cylinder of an airplane engine during its normal operation may be measured for gas intake velocities of from 30 to 35 m/s and for velocities within the cylinder of from 20 to 25 m/s. With it the influence of mixture ratios, of turbulence, of compression ratio and kind of fuel on combustion velocity may be determined. Besides the determination of the influence of the above factors on combustion velocity, the degree of turbulence may also be determined. As a unit of reference in estimating the degree of turbulence, the intake velocity of the charge is chosen.

Schnauffer, Kurt

1932-01-01

94

Swozzle based burner tube premixer including inlet air conditioner for low emissions combustion  

DOEpatents

A burner for use in a combustion system of a heavy-duty industrial gas turbine includes a fuel/air premixer having an air inlet, a fuel inlet, and an annular mixing passage. The fuel/air premixer mixes fuel and air into a uniform mixture for injection into a combustor reaction zone. The burner also includes an inlet flow conditioner disposed at the air inlet of the fuel/air premixer for controlling a radial and circumferential distribution of incoming air. The pattern of perforations in the inlet flow conditioner is designed such that a uniform air flow distribution is produced at the swirler inlet annulus in both the radial and circumference directions. The premixer includes a swozzle assembly having a series of preferably air foil shaped turning vanes that impart swirl to the airflow entering via the inlet flow conditioner. Each air foil contains internal fuel flow passages that introduce natural gas fuel into the air stream via fuel metering holes that pass through the walls of the air foil shaped turning vanes. By injecting fuel in this manner, an aerodynamically clean flow field is maintained throughout the premixer. By injecting fuel via two separate passages, the fuel/air mixture strength distribution can be controlled in the radial direction to obtain optimum radial concentration profiles for control of emissions, lean blow outs, and combustion driven dynamic pressure activity as machine and combustor load are varied.

Tuthill, Richard Sterling (Bolton, CT); Bechtel, II, William Theodore (Scotia, NY); Benoit, Jeffrey Arthur (Scotia, NY); Black, Stephen Hugh (Duanesburg, NY); Bland, Robert James (Clifton Park, NY); DeLeonardo, Guy Wayne (Scotia, NY); Meyer, Stefan Martin (Troy, NY); Taura, Joseph Charles (Clifton Park, NY); Battaglioli, John Luigi (Glenville, NY)

2002-01-01

95

Numerical Investigation of Hydrogen and Kerosene Combustion in Supersonic Air Streams  

NASA Technical Reports Server (NTRS)

The effect of mixing schemes on the combustion of both gaseous hydrogen and liquid kerosene is investigated. Injecting pilot gaseous hydrogen parallel to the supersonic incoming air tends to maintain the stabilization of the main liquid kerosene, which is normally injected. Also the maximum kerosene equivalence ratio that can maintain stable flame can be increased by increasing the pilot energy level. The wedge flame holding contributes to an increased kerosene combustion efficiency by the generation of shock-jet interaction.

Taha, A. A.; Tiwari, S. N.; Mohieldin, T. O.

1999-01-01

96

Large Eddy simulation of turbulent hydrogen-fuelled supersonic combustion in an air cross-flow  

NASA Astrophysics Data System (ADS)

The main aim of this article is to provide a theoretical understanding of the physics of supersonic mixing and combustion. Research in advanced air-breathing propulsion systems able to push vehicles well beyond is of interest around the world. In a scramjet, the air stream flow captured by the inlet is decelerated but still maintains supersonic conditions. As the residence time is very short , the study of an efficient mixing and combustion is a key issue in the ongoing research on compressible flows. Due to experimental difficulties in measuring complex high-speed unsteady flowfields, the most convenient way to understand unsteady features of supersonic mixing and combustion is to use computational fluid dynamics. This work investigates supersonic combustion physics in the Hyshot II combustion chamber within the Large Eddy simulation framework. The resolution of this turbulent compressible reacting flow requires: (1) highly accurate non-dissipative numerical schemes to properly simulate strong gradients near shock waves and turbulent structures away from these discontinuities; (2) proper modelling of the small subgrid scales for supersonic combustion, including effects from compressibility on mixing and combustion; (3) highly detailed kinetic mechanisms (the Warnatz scheme including 9 species and 38 reactions is adopted) accounting for the formation and recombination of radicals to properly predict flame anchoring. Numerical results reveal the complex topology of the flow under investigation. The importance of baroclinic and dilatational effects on mixing and flame anchoring is evidenced. Moreover, their effects on turbulence-scale generation and the scaling law are analysed.

Ingenito, A.; Cecere, D.; Giacomazzi, E.

2013-09-01

97

Air by-pass system in an internal combustion engine with a supercharger  

SciTech Connect

An air by-pass system is disclosed in an internal combustion engine with a turbocharger which comprises a compressor driven by an exhaust gas turbine for supercharging suction air fed to the engine through a throttle valve, wherein an air by-pass passage is provided for connecting an area upstream from the compressor and an area downstream from the throttle valve, and an air valve is provided in the by-pass passage for controlling the amount of the by-pass air.

Sone, Sh.; Ikuta, Y.; Kihira, K.; Komiya, K.; Mizuno, N.

1984-05-22

98

COMBUSTION OF AEROSOLIZED SPHERICAL ALUMINUM POWDERS AND FLAKES IN AIR  

Microsoft Academic Search

Combustion rates and completeness of aerosolized spherical aluminum powders and flakes are compared using constant volume explosion experiments. The comparison of particles and flake sizes was made based on their specific surface areas determined using the Brunauer–Emmett–Teller (BET) method and respective “BET diameters.” It is observed that the rates of pressure rise and respective rates of flame propagation were higher

B. Z. EAPEN; V. K. HOFFMANN; M. SCHOENITZ; E. L. DREIZIN

2004-01-01

99

A comparative assessment of alternative combustion turbine inlet air cooling system  

SciTech Connect

Interest in combustion turbine inlet air cooling (CTAC) has increased during the last few years as electric utilities face increasing demand for peak power. Inlet air cooling increases the generating capacity and decreases the heat rate of a combustion turbine during hot weather when the demand for electricity is generally the greatest. Several CTAC systems have been installed, but the general applicability of the concept and the preference for specific concepts is still being debated. Concurrently, Rocky Research of Boulder City, Nevada has been funded by the U.S. Department of Energy to conduct research on complex compound (ammoniated salt) chiller systems for low-temperature refrigeration applications.

Brown, D.R.; Katipamula, S.; Konynenbelt, J.H.

1996-02-01

100

Control installation for the proportioning of a secondary air quantity for achieving optimum combustion or after-burning in internal combustion engines  

Microsoft Academic Search

A control installation is described for the proportioning of a secondary air quantity employed for achieving optimum combustion or after-burning in internal combustion engines. The installation provides for stabilization of the measuring receptivity of sensors employed for the measurement of the oxygen content or carbon monoxide content of the exhaust gases, and to reduce the load on a subsequently switched-in

Haertel

1976-01-01

101

Retene-a molecular marker of wood combustion in ambient air  

NASA Astrophysics Data System (ADS)

The use of wood as a fuel has increased since the oil embargo in 1973. Several studies have shown that wood combustion may make a significant contribution to air pollution. Using 14C as a tracer for contemporary carbonaceous materials, 30-70% of the atmospheric carbon has been shown to originate from wood combustion in areas affected by this source1-3. Other studies have shown that emissions from wood combustion contain large amounts of particles4-6 and organic compounds, one class being poly cyclic aromatic hydrocarbons (PAH)7-11. However, these compounds are also formed by combustion of other carbonaceous materials. In our studies on PAH in wood combustion emissions and in ambient air in wood-heated residential areas, we have identified several PAH compounds which may be related to combustion of coniferous wood. These are alkylated phenanthrene compounds with the main compound 1-methyl-7-isopropylphenanthrene (trivial name retene) formed by thermal degradation of resin compounds in the wood.

Ramdahl, Thomas

1983-12-01

102

Reduction in nitrogen oxide concentration in homogenous combustion of methane and its mixtures with nitrogenous substances in air  

Microsoft Academic Search

Experiments were carried out with a jet apparatus with laminar flame at atmosperic pressure in order to study the two-step combustion of pure methane-air mixtures and similar mixtures with nitrogenous substances - methylamine and pyridine - added. The first series of experiments used methane-air mixtures. During combustion, nitrogen oxide was formed from atmospheric nitrogen. In the second series of experiments

S. M. Kogarkov; V. Y. Basevich; A. N. Tyurin

1985-01-01

103

Combustion Gas Properties I-ASTM Jet a Fuel and Dry Air  

NASA Technical Reports Server (NTRS)

A series of computations was made to produce the equilibrium temperature and gas composition for ASTM jet A fuel and dry air. The computed tables and figures provide combustion gas property data for pressures from 0.5 to 50 atmospheres and equivalence ratios from 0 to 2.0.

Jones, R. E.; Trout, A. M.; Wear, J. D.; Mcbride, B. J.

1984-01-01

104

PIC (PRODUCTS OF INCOMPLETE COMBUSTION) FORMATION UNDER PYROLYTIC AND STARVED AIR CONDITIONS  

EPA Science Inventory

A comprehensive program of laboratory studies based on the non-flame mode of thermal decomposition produced much data on PIC (Products of Incomplete Combustion) formation, primarily under pyrolytic and starved air conditions. Most significantly, laboratory results from non-flame ...

105

BATTERY POWERED PM-10 INDOOR AIR SAMPLERS APPLIED TO UNVENTED THIRD WORLD RESIDENTIAL COMBUSTION SOURCES  

EPA Science Inventory

The paper discusses a battery-powered PM-10 indoor air sampler applied to unvented Third World residential combustion sources. (NOTE: Specialized PM-10 sampling systems have been developed and used in support of a joint U.S. EPA/People's Republic of China Institute of Environment...

106

Air pollution from aircraft. [jet exhaust - aircraft fuels/combustion efficiency  

NASA Technical Reports Server (NTRS)

A model which predicts nitric oxide and carbon monoxide emissions from a swirl can modular combustor is discussed. A detailed analysis of the turbulent fuel-air mixing process in the swirl can module wake region is reviewed. Hot wire anemometry was employed, and gas sampling analysis of fuel combustion emissions were performed.

Heywood, J. B.; Chigier, N. A.

1975-01-01

107

Combustion Turbine Inlet Air Cooling (CTIAC): Benefits, Technology Options, and Applications for District Energy  

Microsoft Academic Search

Combustion turbines (CTs) are increasingly used for electric power generation in combined heat & power (CHP) applications, including those in the district energy arena. CTs exhibit an inherent loss in power output as ambient air temperature rises, at precisely those times when power is most in demand and most highly valued.This article presents the concepts, and the benefits, of cooling

John S. Andrepont

2001-01-01

108

HAZARDOUS AIR POLLUTANTS FROM THE COMBUSTION OF AN EMULSIFIED HEAVY FUEL OIL IN A FIRETUBE BOILER  

EPA Science Inventory

The report gives results of measuring emissions of hazardous air pollutants (HAPs) from the combustion flue gases of a No. 6 fuel oil, both with and without an emulsifying agent, in a 2.5 million Btu/hr (732 kW) firetube boiler with the purpose of determining the impacts of the e...

109

EPA'S STUDY OF THE GENERATION AND CONTROL OF AIR POLLUTANTS FROM THE COMBUSTION OF ORIMULSION  

EPA Science Inventory

The paper discusses an EPA study of the grneration and control of air pollutants from the combustion of Orimulsion, a high-sulfur liquid petroleum fuel composed of approximately 70% Venezuelan bitumen, 30% water, and trace amounts of surfactant. (NOTE: It is being used as the pri...

110

Effects of catalytic walls on hydrogen\\/air combustion inside a micro-tube  

Microsoft Academic Search

Numerical simulations with detailed heterogeneous and homogeneous chemistries of hydrogen\\/air mixture reactions inside a catalytic micro-tube were performed. The characteristics of heterogeneous and homogeneous interaction are delineated in terms of flow velocity, tube diameter and wall thermal conductivity. With the catalytic wall, the homogeneous combustion is obviously weakened. The heterogeneous reactions will consume part of the fuel near the entrance

Guan-Bang Chen; Chih-Peng Chen; Chih-Yung Wu; Yei-Chin Chao

2007-01-01

111

Experimental investigation of wood combustion in a fixed bed with hot air.  

PubMed

Waste combustion on a grate with energy recovery is an important pillar of municipal solid waste (MSW) management in the Netherlands. In MSW incinerators fresh waste stacked on a grate enters the combustion chamber, heats up by radiation from the flame above the layer and ignition occurs. Typically, the reaction zone starts at the top of the waste layer and propagates downwards, producing heat for drying and devolatilization of the fresh waste below it until the ignition front reaches the grate. The control of this process is mainly based on empiricism. MSW is a highly inhomogeneous fuel with continuous fluctuating moisture content, heating value and chemical composition. The resulting process fluctuations may cause process control difficulties, fouling and corrosion issues, extra maintenance, and unplanned stops. In the new concept the fuel layer is ignited by means of preheated air (T>220 °C) from below without any external ignition source. As a result a combustion front will be formed close to the grate and will propagate upwards. That is why this approach is denoted by upward combustion. Experimental research has been carried out in a batch reactor with height of 4.55 m, an inner diameter of 200 mm and a fuel layer height up to 1m. Due to a high quality two-layer insulation adiabatic conditions can be assumed. The primary air can be preheated up to 350 °C, and the secondary air is distributed via nozzles above the waste layer. During the experiments, temperatures along the height of the reactor, gas composition and total weight decrease are continuously monitored. The influence of the primary air speed, fuel moisture and inert content on the combustion characteristics (ignition rate, combustion rate, ignition front speed and temperature of the reaction zone) is evaluated. The upward combustion concept decouples the drying, devolatilization and burnout phase. In this way the moisture and inert content of the waste have almost no influence on the combustion process. In this paper an experimental comparison between conventional and reversed combustion is presented. PMID:24125795

Markovic, Miladin; Bramer, Eddy A; Brem, Gerrit

2014-01-01

112

Numerical Study of Contaminant Effects on Combustion of Hydrogen, Ethane, and Methane in Air  

NASA Technical Reports Server (NTRS)

A numerical study was performed to assess the effects of vitiated air on the chemical kinetics of hydrogen, ethane, and methane combustion with air. A series of calculations in static reacting systems was performed, where the initial temperature was specified and reactions occurred at constant pressure. Three different types of test flow contaminants were considered: NP, H2O, and a combustion of H2O and CO2. These contaminants are present in the test flows of facilities used for hypersonic propulsion testing. The results were computed using a detailed reaction mechanism and are presented in terms of ignition and reaction times. Calculations were made for a wide range of contaminant concentrations, temperatures and pressures. The results indicate a pronounced kinetic effect over a range of temperatures, especially with NO contamination and, to a lesser degree, with H2O contamination. In all cases studied, CO2 remained kinetically inert, but had a thermodynamic effect on results by acting as a third body. The largest effect is observed with combustion using hydrogen fuel, less effect is seen with combustion of ethane, and little effect of contaminants is shown with methane combustion.

Lai, H. T.; Thomas, S. R.

1995-01-01

113

Analysis of Fuel Vaporization, Fuel-Air Mixing, and Combustion in Integrated Mixer-Flame Holders  

NASA Technical Reports Server (NTRS)

Requirements to limit pollutant emissions from the gas turbine engines for the future High-Speed Civil Transport (HSCT) have led to consideration of various low-emission combustor concepts. One such concept is the Integrated Mixer-Flame Holder (IMFH). This report describes a series of IMFH analyses performed with KIVA-II, a multi-dimensional CFD code for problems involving sprays, turbulence, and combustion. To meet the needs of this study, KIVA-II's boundary condition and chemistry treatments are modified. The study itself examines the relationships between fuel vaporization, fuel-air mixing, and combustion. Parameters being considered include: mixer tube diameter, mixer tube length, mixer tube geometry (converging-diverging versus straight walls), air inlet velocity, air inlet swirl angle, secondary air injection (dilution holes), fuel injection velocity, fuel injection angle, number of fuel injection ports, fuel spray cone angle, and fuel droplet size. Cases are run with and without combustion to examine the variations in fuel-air mixing and potential for flashback due to the above parameters. The degree of fuel-air mixing is judged by comparing average, minimum, and maximum fuel/air ratios at the exit of the mixer tube, while flame stability is monitored by following the location of the flame front as the solution progresses from ignition to steady state. Results indicate that fuel-air mixing can be enhanced by a variety of means, the best being a combination of air inlet swirl and a converging-diverging mixer tube geometry. With the IMFH configuration utilized in the present study, flashback becomes more common as the mixer tube diameter is increased and is instigated by disturbances associated with the dilution hole flow.

Deur, J. M.; Cline, M. C.

2004-01-01

114

GASEOUS EMISSIONS FROM EXCESS AIR COMBUSTION OF EXPLOSIVES AND PROPELLANTS  

EPA Science Inventory

The purpose of this short-term project was to determine the levels of nitric oxide (NO), nitrogen dioxide (NO2), and carbon monoxide (CO) in the off-gases from the open burning of explosives in excess air. The ultimate goal is to reduce the level of NO(x), CO, and particulates em...

115

Air toxic emissions from the combustion of coal: Identifying and quantifying hazardous air pollutants from US coals  

SciTech Connect

This report addresses the key air toxic emissions likely to emanate from continued and expanded use of domestic coal. It identifies and quantifies those trace elements specified in the US 1990 Clean Air Act Amendments, by tabulating selected characterization data on various source coals by region, state, and rank. On the basis of measurements by various researchers, this report also identifies those organic compounds likely to be derived from the coal combustion process (although their formation is highly dependent on specific boiler configurations and operating conditions).

Szpunar, C.B.

1992-09-01

116

Investigation on combustion characteristics and NO formation of methane with swirling and non-swirling high temperature air  

NASA Astrophysics Data System (ADS)

Combustion characteristics of methane jet flames in an industrial burner working in high temperature combustion regime were investigated experimentally and numerically to clarify the effects of swirling high temperature air on combustion. Speziale-Sarkar-Gatski (SSG) Reynolds stress model, Eddy-Dissipation Model (EDM), Discrete Ordinates Method (DTM) combined with Weighted-Sum-of-Grey Gases Model (WSGG) were employed for the numerical simulation. Both Thermal-NO and Prompt-NO mechanism were considered to evaluate the NO formation. Temperature distribution, NO emissions by experiment and computation in swirling and non-swirling patterns show combustion characteristics of methane jet flames are totally different. Non-swirling high temperature air made high NO formation while significant NO prohibition were achieved by swirling high temperature air. Furthermore, velocity fields, dimensionless major species mole fraction distributions and Thermal-NO molar reaction rate profiles by computation interpret an inner exhaust gas recirculation formed in the combustion zone in swirling case.

Li, Xing; Jia, Li

2014-10-01

117

Visualization research on high efficiency and low NOx combustion technology with multiple air-staged and large angle counter flow of fuel-rich jet  

Microsoft Academic Search

In this paper, a new technique for tangentially fired pulverized coal boiler, high efficiency and low NOx combustion technology with multiple air-staged and large angle counter flow of fuel-rich jet (ACCT for short), is proposed. Based on traditional air staged and rich-lean combustion technique, a NOx reduction area is introduced through air injection between primary combustion zone and secondary combustion

Y. Y. Li; Z. C. Lin; W. D. Fan; M. C. Zhang

2010-01-01

118

Numerical study of contaminant effects on combustion of hydrogen, ethane, and methane in air  

NASA Technical Reports Server (NTRS)

A numerical study was performed to assess the effects of vitiated air on the chemical kinetics of hydrogen, ethane, and methane combustion with air. A series of calculations in static reacting systems was performed, where the initial temperature was specified and reactions occurred at constant pressure. Three different types of test flow contaminants were considered: NO, H2O, and a combination of H2O and CO2. These contaminants are present in the test flows of facilities used for hypersonic propulsion testing. The results were computed using a detailed reaction mechanism and are presented in terms of ignition and reaction times. Calculations were made for a wide range of contaminant concentrations, temperatures and pressures. The results indicate a pronounced kinetic effect over a range of temperatures, especially with NO contamination and, to a lesser degree, with H2O contamination. In all cases studied, CO2 remained kinetically inert, but had a thermodynamically effect on results by acting as a third body. The largest effect is observed with combustion using hydrogen fuel, less effect is seen with combustion of ethane, and little effect of contaminants is shown with methane combustion.

Lai, H. T.; Thomas, S. R.

1995-01-01

119

Electromagnetically-controlled valve, suitable for controlling an additional air flow in a feed equipment for an internal combustion engine  

Microsoft Academic Search

An electromagnetically controlled valve is described for controlling additional air flow delivered by feed equipment associated with an internal combustion engine. The feed equipment includes at least an engine intake passage and a throttle valve disposed in the passage. The electromagnetically controlled valve consists of: an air inlet for air coming from a first part of the intake passage, the

Busacchi

1986-01-01

120

Mechanical-activation-assisted combustion synthesis of {alpha}-SiAlON in air  

SciTech Connect

With the assistance of mechanical activation, yttrium-stabilized {alpha}-SiAlON was prepared by combustion synthesis in air, instead of high-pressure N{sub 2} atmosphere for the first time. The reaction activity of metallic particles was remarkably enhanced by mechanical activation, which conduced the reduction of grain size, increased the total surface area and formation of fresh surface. The formation of {alpha}-SiAlON by combustion synthesis in air was explained by a kinetically induced reaction mechanism, in which both initial formation of {alpha}-SiAlON and following avoidance of oxidation were fulfilled by the retardation of O{sub 2} infiltration owing to the short reaction period and fast cooling rate.

Liu Guanghua [Department of Materials Science and Engineering, State Key Laboratory of New Ceramics and Fine Processing, Tsinghua University, 100084 Beijing (China); Chen Kexin [Department of Materials Science and Engineering, State Key Laboratory of New Ceramics and Fine Processing, Tsinghua University, 100084 Beijing (China)]. E-mail: kxchen@mail.tsinghua.edu.cn; Zhou Heping [Department of Materials Science and Engineering, State Key Laboratory of New Ceramics and Fine Processing, Tsinghua University, 100084 Beijing (China); Li Jiangtao [Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, 100101 Beijing (China); Pereira, C. [Department of Ceramics and Glass Engineering, University of Aveiro, CICECO, 3810-193 Aveiro (Portugal); Ferreira, J.M.F. [Department of Ceramics and Glass Engineering, University of Aveiro, CICECO, 3810-193 Aveiro (Portugal)

2007-06-05

121

Numerical study of shock-induced combustion in methane-air mixtures  

NASA Technical Reports Server (NTRS)

The shock-induced combustion of methane-air mixtures in hypersonic flows is investigated using a new reaction mechanism consisting of 19 reacting species and 52 elementary reactions. This reduced model is derived from a full kinetic mechanism via the Detailed Reduction technique. Zero-dimensional computations of several shock-tube experiments are presented first. The reaction mechanism is then combined with a fully implicit Navier-Stokes computational fluid dynamics (CFD) code to conduct numerical simulations of two-dimensional and axisymmetric shock-induced combustion experiments of stoichiometric methane-air mixtures at a Mach number of M = 6.61. Applications to the ram accelerator concept are also presented.

Yungster, Shaye; Rabinowitz, Martin J.

1993-01-01

122

Combustion air intake system for wood-burning stove  

SciTech Connect

Hinged doors are provided on the front of a stove for sealably closing across a large opening through which logs can be loaded into a firebox within the stove. A cylindrical draft chamber is formed on an exterior surface of one or each of the doors. A draft cap is rotatable on a threaded stud which is coaxially secured in the cylindrical draft chamber. The draft cap includes an annular flange forming a sliding close-tolerance fit with an interior cylindrical wall of the draft chamber so that the cap can be rotated to vary the size of the draft chamber to selectively restrict the flow of air from a source through the draft chamber to the firebox whenever the doors are closed.

Eisiminger, L.D.

1982-02-23

123

Chemical modelling and measurements of the catalytic combustion of CH 4\\/air mixtures on platinum and palladium catalysts  

Microsoft Academic Search

This work reports experimental measurements and a modelling study carried out on palladium and platinum based catalytic monoliths used as methane combustors for heating purposes. It concentrates on the effects of operating conditions on combustion, heat transfer efficiency and pollutant formation. The development of a detailed homogeneous\\/heterogeneous chemical kinetics model for methane–air combustion over palladium using literature data was undertaken

F. Moallemi; G. Batley; V. Dupont; T. J. Foster; M. Pourkashanian; A. Williams

1999-01-01

124

Completeness of Combustion for Laminar Wall Fires Using Several Alcohols Burning in Air  

Microsoft Academic Search

Steady, fully-burning wall fires were studied for several alcohols burning in air. Methanol, 1-propanol. and 1-butanol were burned using a vertically-oriented porous ceramic wick. Completeness of combustion was evaluated and accounting for its effect in numerical modeling, on characteristics of laminar wall fires was examined. Measurements of the concentration profiles in the free-convection boundary layers formed revealed that for each

STEVEN F. MALARY; JEAN K. AWAD; RAJENDER THAPAR

1989-01-01

125

Modeling, Dynamic Simulation, and Controller Design for an Air-breathing Combustion System  

Microsoft Academic Search

A novel, high-fidelity, low-order model is developed for an air-breathing combustion system designed for supersonic flight with a subsonic combustor. Individual components - intake, combustor, exhaust nozzle - are modeled with detailed models obtained from CFD, quasi-1D, or isentropic analysis, as the case may be. The components are then interlinked by a low-order global model that captures the physics of

P. Bharani; Chandra Kumar; Nitin K. Gupta; N. Ananthkrishnan; V. S. Renganathan

2009-01-01

126

Analytical evaluation of effect of equivalence ratio inlet-air temperature and combustion pressure on performance of several possible ram-jet fuels  

NASA Technical Reports Server (NTRS)

The results of an analytical investigation of the theoretical air specific impulse performance and adiabatic combustion temperatures of several possible ram-jet fuels over a range of equivalence ratios, inlet-air temperatures, and combustion pressures, is presented herein. The fuels include octane-1, 50-percent-magnesium slurry, boron, pentaborane, diborane, hydrogen, carbon, and aluminum. Thermal effects from high combustion temperatures were found to effect considerably the combustion performance of all the fuels. An increase in combustion pressure was beneficial to air specific impulse at high combustion temperatures. The use of these theoretical data in engine operation and in the evaluation of experimental data is described.

Tower, Leonard K; Gammon, Benson E

1953-01-01

127

Catalytic Combustion of Propane/Air Mixtures on Platinum  

NASA Technical Reports Server (NTRS)

A honeycomb catalyst of platinum (4.2 kg/cu m loading) over cordierite, with gamma-alumina washcoat, a cross section of 2.4 x 2.4 sq cm, a length of 7.6 cm, and a characteristic channel diameter of 1.4 mm is used as a steady flow reactor. Measurements are made with C3H8/air mixtures at 650 to 800 K inlet temperatures, 110 KPa pressure, 10 to 40 m/s inlet velocity, 0.19 to 0.32 equivalence ratios, and approximately 1.5 mole percent water content. The measured quantities are the substrate tempeature at ten axial locations, the exhaust gas temperature, the exhaust concentrations of CO, CO2, O2, and total hydrocarbons, and the pressure drop across the monolith. The measured quantities are compared with those computed with a two-dimensional steady-state model for axial and radial convection and diffusion of mass, momentum, energy and homogeneous (three overall reactions) and heterogeneous (infinitely fast) reactions. It is found that, under the tested conditions, most of the fuel is converted to CO2 and H2O at the surface. Gas-phase reactions tend rapidly to become more important as the temperature and equivalence ratio are increased and the flow velocity is decreased. Surface fuel conversion is much more rapid than fuel diffusion, resulting in diffusion-controlled oxidation.

Bruno, C.; Walsh, P. M.; Santavicca, D. A.; Sinha, N.; Bracco, F. V.; Yaw, Y.

1983-01-01

128

Device for admitting exhaust gases and fuel-air mixtures into the cylinders of an internal combustion engine  

Microsoft Academic Search

A device is proposed for the supply of operating air-fuel mixtures including exhaust gases to internal combustion engines. Between the opening periods of the inlet valves of an internal combustion engine, precisely dispensed quantities of recirculated exhaust gas are pre-stored in the intake channel directly upstream of the inlet valve whereby a stratification of exhaust gas and fuel-air mixture in

K. Eckert; H. Britsch; E. Linder; K. Muller; W. Polach

1984-01-01

129

Method of regulating the amount of underfire air for combustion of wood fuels in spreader-stroke boilers  

DOEpatents

A method of metering underfire air for increasing efficiency and reducing particulate emissions from wood-fire, spreader-stoker boilers is disclosed. A portion of the combustion air, approximately one pound of air per pound of wood, is fed through the grate into the fuel bed, while the remainder of the combustion air is distributed above the fuel in the furnace, and the fuel bed is maintained at a depth sufficient to consume all oxygen admitted under fire and to insure a continuous layer of fresh fuel thereover to entrap charred particles inside the fuel bed.

Tuttle, Kenneth L. (Federal Way, WA)

1980-01-01

130

77 FR 37361 - National Emission Standards for Hazardous Air Pollutants for Reciprocating Internal Combustion...  

Federal Register 2010, 2011, 2012, 2013, 2014

...Pollutants for Reciprocating Internal Combustion Engines; New Source Performance Standards for Stationary Internal Combustion Engines AGENCY: Environmental...Pollutants for Reciprocating Internal Combustion Engines; New Source...

2012-06-21

131

76 FR 12863 - National Emission Standards for Hazardous Air Pollutants for Reciprocating Internal Combustion...  

Federal Register 2010, 2011, 2012, 2013, 2014

...Pollutants for Reciprocating Internal Combustion Engines AGENCY: Environmental...ignition reciprocating internal combustion engines. The final rule was published...Stationary Reciprocating Internal Combustion Engines Docket, Docket ID...

2011-03-09

132

76 FR 12923 - National Emission Standards for Hazardous Air Pollutants for Reciprocating Internal Combustion...  

Federal Register 2010, 2011, 2012, 2013, 2014

...Pollutants for Reciprocating Internal Combustion Engines AGENCY: Environmental...ignition reciprocating internal combustion engines. The final rule was...Electric power reciprocating internal combustion generation, engine. transmission, or...

2011-03-09

133

75 FR 37732 - National Emission Standards for Hazardous Air Pollutants for Reciprocating Internal Combustion...  

Federal Register 2010, 2011, 2012, 2013, 2014

...Pollutants for Reciprocating Internal Combustion Engines AGENCY: Environmental...ignition reciprocating internal combustion engines. The amendments inadvertently...ignition reciprocating internal combustion engines. 40 CFR 63.6590...

2010-06-30

134

The impacts of combustion emissions on air quality and climate - From coal to biofuels and beyond  

NASA Astrophysics Data System (ADS)

Combustion processes have inherent characteristics that lead to the release in the environment of both gaseous and particulate pollutants that have primary and secondary impacts on air quality, human health, and climate. The emissions from the combustion of fossil fuels and biofuels and their atmospheric impacts are reviewed here with attention given to the emissions of the currently regulated pollutant gasses, primary aerosols, and secondary aerosol precursors as well as the emissions of non-regulated pollutants. Fuels ranging from coal, petroleum, liquefied petroleum gas (LPG), natural gas, as well as the biofuels; ethanol, methanol, methyl tertiary-butyl ether (MTBE), ethyl tertiary-butyl ether (ETBE), and biodiesel, are discussed in terms of the known air quality and climate impacts of the currently regulated pollutants. The potential importance of the non-regulated emissions of both gasses and aerosols in air quality issues and climate is also discussed with principal focus on aldehydes and other oxygenated organics, polycyclic aromatic hydrocarbons (PAHs), and nitrated organics. The connection between air quality and climate change is also addressed with attention given to ozone and aerosols as potentially important greenhouse species.

Gaffney, Jeffrey S.; Marley, Nancy A.

135

Fate of hazardous air pollutants in oxygen-fired coal combustion with different flue gas recycling.  

PubMed

Experiments were performed to characterize transformation and speciation of hazardous air pollutants (HAPs), including SO(2)/SO(3), NO(x), HCl, particulate matter, mercury, and other trace elements in oxygen-firing bituminous coal with recirculation flue gas (RFG) from 1) an electrostatic precipitator outlet or 2) a wet scrubber outlet. The experimental results showed that oxycombustion with RFG generated a flue gas with less volume and containing HAPs at higher levels, while the actual emissions of HAPs per unit of energy produced were much less than that of air-blown combustion. NO(x) reduction was achieved in oxycombustion because of the elimination of nitrogen and the destruction of NO in the RFG. The elevated SO(2)/SO(3) in flue gas improved sulfur self-retention. SO(3) vapor could reach its dew point in the flue gas with high moisture, which limits the amount of SO(3) vapor in flue gas and possibly induces material corrosion. Most nonvolatile trace elements were less enriched in fly ash in oxycombustion than air-firing because of lower oxycombustion temperatures occurring in the present study. Meanwhile, Hg and Se were found to be enriched on submicrometer fly ash at higher levels in oxy-firing than in air-blown combustion. PMID:22439940

Zhuang, Ye; Pavlish, John H

2012-04-17

136

Laser Diagnostics of Combustion Enhancement on a CH4/Air Bunsen Flame by Dielectric Barrier Discharge  

NASA Astrophysics Data System (ADS)

We investigate plasma-assisted combustion for premixed CH4/air Bunsen flames. Dielectric barrier discharge (DBD) is employed to produce non-equilibrium plasma for combustion enhancement. The transient planar laser induced fluorescence (PLIF) technique of CH and OH radicals is used to image reaction zones for enhancement measurement, and the emission spectra of the Bunsen flame are monitored to explore the kinetics mechanism. From the drift of radicals in PLIF images, the quantitative enhancement of plasma on the flame velocities of premixed methane/air flames is experimentally measured, and the data show that the flame velocities are increased by at least 15% in the presented equivalence ratio range. Furthermore, the well analyzed emission spectra of the Bunsen flame (300-800 nm) with/without DBD reveal that the emissions as well as the concentrations of the crucial radicals (like C2, CH, OH etc.) in combustion all are intensified greatly by the discharge. In addition, the appearance of excited spectral bands of N2 and N+2 during discharge indicates that the premixed gas is also heated and ionized partially by the DBD.

Zhang, Shao-Hua; Yu, Xi-Long; Chen, Li-Hong; Zhang, Xin-Yu

2013-08-01

137

Combustion  

NASA Technical Reports Server (NTRS)

An overview of the emissions related research being conducted as part of the Fundamental Aeronautics Subsonics Fixed Wing Project is presented. The overview includes project metrics, milestones, and descriptions of major research areas. The overview also includes information on some of the emissions research being conducted under NASA Research Announcements. Objective: Development of comprehensive detailed and reduced kinetic mechanisms of jet fuels for chemically-reacting flow modeling. Scientific Challenges: 1) Developing experimental facilities capable of handling higher hydrocarbons and providing benchmark combustion data. 2) Determining and understanding ignition and combustion characteristics, such as laminar flame speeds, extinction stretch rates, and autoignition delays, of jet fuels and hydrocarbons relevant to jet surrogates. 3) Developing comprehensive kinetic models for jet fuels.

Bulzan, Dan

2007-01-01

138

Combustion  

NSDL National Science Digital Library

In this chemistry activity, learners discover that the weight of the product of combustion is greater than that of the starting material. Learners will compare the weight of steel wool before and after it is heated. Learners are asked to consider why the steel wool weighs more (oxidation) as well as write the balanced chemical equation for the burning of steel. This activity uses an open flame; adult supervision is recommended. The resource includes notes for educators and extension ideas.

2014-01-28

139

Starved air combustion-solidification/stabilization of primary chemical sludge from a tannery.  

PubMed

The high concentration of trivalent chromium along with organic/inorganic compounds in tannery sludge causes severe ground water contamination in the case of land disposal and chronic air pollution during incineration. In the present investigation, the sludge was subjected to flow-through column test to evaluate the concentration of leachable organics (tannin, COD and TOC) and heavy metal ions (Cr(3+), Fe(2+)) present in it. The dried sludge was incinerated at 800 degrees C in an incinerator under starved oxygen supply (starved-air combustion) to prevent the conversion of Cr(3+) to Cr(6+). The efficiency of starved air combustion was studied under different loading rates of sludge. The calcined sludge was solidified/stabilized using fly ash and Portland cement/gypsum. The solidified bricks were tested for unconfined compressive strength and heavy metal leaching. Unconfined compressive strength of the blocks was in the range of 83-156 kg/cm(2). The stabilization of chromium (III) in the cement gel matrix was confirmed with scanning electron microscopy (SEM) and X-ray energy dispersive spectroscopy (EDX). Leachability studies on solidified bricks were carried out to determine the metal fixation and dissolved organic (as COD) concentration in the leachate. PMID:16563614

Swarnalatha, S; Ramani, K; Karthi, A Geetha; Sekaran, G

2006-09-01

140

Study of effects of injector geometry on fuel-air mixing and combustion  

NASA Technical Reports Server (NTRS)

An implicit finite-difference method has been developed for computing the flow in the near field of a fuel injector as part of a broader study of the effects of fuel injector geometry on fuel-air mixing and combustion. Detailed numerical results have been obtained for cases of laminar and turbulent flow without base injection, corresponding to the supersonic base flow problem. These numerical results indicated that the method is stable and convergent, and that significant savings in computer time can be achieved, compared with explicit methods.

Bangert, L. H.; Roach, R. L.

1977-01-01

141

Innovative Approaches to Fuel-Air Mixing and Combustion in Airbreathing Hypersonic Engines  

NASA Astrophysics Data System (ADS)

This paper describes some innovative methods for achieving enhanced fuel-air mixing and combustion in Scramjet-like spaceplane engines. A multimodal approach to the problem is discussed; this involves using several concurrent methods of forced mixing. The paper concentrates on Electromagnetic Activation (EMA) and Electrostatic Attraction as suitable techniques for this purpose - although several other potential methods are also discussed. Previously published empirical data is used to draw conclusions about the likely effectiveness of the system and possible engine topologies are outlined.

MacLeod, C.

142

Development of a hybrid-fuzzy air temperature controller for a supersonic combustion test facility  

NASA Astrophysics Data System (ADS)

Hydrogen gas is burned in air to raise and maintain the stagnation temperature of a supersonic combustion test facility to a desired setpoint. In order to reach the desired operating conditions for stagnation temperature, there are three phases to the hydrogen control; H2 ignition at facility start-up, H2 ramp-up while the facility is ramped-up, and H2 iteration to achieve the desired temperature setpoint. Each phase incorporates a different type of control. Fuzzy logic is used to design a computer based supervisory controller that recognizes the different phases of operation and chooses the appropriate control method.

Owens, M.; Segal, C.

143

Transient air-fuel ratio H? preview control of a drive-by-wire internal combustion engine  

Microsoft Academic Search

An approach for H? Preview control of the transient air-fuel ratio control of a drive-by-wire internal combustion engine system is proposed. The fuel delivery system has significant transport and measurement delays. A preview fuel control algorithm, which uses the current measurement or estimate of air charge as well as the corresponding predicted future air charge, provides compensation for these delays.

Larry Mianzot; Huei Pengt; I. Haskara

2001-01-01

144

Fuel-air mixing and combustion in a two-dimensional Wankel engine  

NASA Technical Reports Server (NTRS)

A two-equation turbulence model, an algebraic grid generalization method, and an approximate factorization time-linearized numerical technique are used to study the effects of mixture stratification at the intake port and gaseous fuel injection on the flow field and fuel-air mixing in a two-dimensional rotary engine model. The fuel distribution in the combustion chamber is found to be a function of the air-fuel mixture fluctuations at the intake port. It is shown that the fuel is advected by the flow field induced by the rotor and is concentrated near the leading apex during the intake stroke, while during compression, the fuel concentration is highest near the trailing apex and is lowest near the rotor. It is also found that the fuel concentration near the trailing apex and rotor is small except at high injection velocities.

Shih, T. I.-P.; Schock, H. J.; Ramos, J. I.

1987-01-01

145

Thermodynamic and transport combustion properties of hydrocarbons with air. Part 1: Properties in SI units  

NASA Technical Reports Server (NTRS)

Thermodynamic and transport combustion properties were calculated for a wide range of conditions for the reaction of hydrocarbons with air. Three hydrogen-carbon atom ratios (H/C = 1.7, 2.0, 2.1) were selected to represent the range of aircraft fuels. For each of these H/C ratios, combustion properties were calculated for the following conditions: Equivalence ratio: 0, 0.25, 0.5, 0.75, 1.0, 1.25 Water - dry air mass ratio: 0, 0.03 Pressure, kPa: 1.01325, 10.1325, 101.325, 1013.25, 5066.25 (or in atm: 0.01, 0.1, 1, 10, 50) Temperature, K: every 10 degrees from 200 to 900 K; every 50 degrees from 900 to 3000 K Temperature, R: every 20 degrees from 360 to 1600 R; very 100 degrees from 1600 to 5400 R. The properties presented are composition, density, molecular weight, enthalphy, entropy, specific heat at constant pressure, volume derivatives, isentropic exponent, velocity of sound, viscosity, thermal conductivity, and Prandtl number. Property tables are based on composites that were calculated by assuming both: (1) chemical equilibrium (for both homogeneous and heterogeneous phases) and (2) constant compositions for all temperatures. Properties in SI units are presented in this report for the Kelvin temperature schedules.

Gordon, S.

1982-01-01

146

Uncertainty for data with non-detects: Air toxic emissions from combustion  

SciTech Connect

Air toxic emission factor datasets often contain one or more points below a single or multiple detection limits and such datasets are referred to as 'censored.' Conventional methods used to deal with censored datasets include removing non-detects, replacing the censored points with zero, half of the detection limit, or the detection limit. However, the estimated means of the censored dataset by conventional methods are usually biased. Maximum likelihood estimation (MLE) and bootstrap simulation have been demonstrated as a statistically robust method to quantify variability and uncertainty of censored datasets and can provide asymptotically unbiased mean estimates. The MLE/bootstrap method is applied to 16 cases of censored air toxic emission factors, including benzene, formaldehyde, benzo(a)pyrene, mercury, arsenic, cadmium, total chromium, chromium VI and lead from coal, fuel oil, and/or wood waste external combustion sources. The proportion of censored values in the emission factor data ranges from 4 to 80%. Key factors that influence the estimated uncertainty in the mean of censored data are sample size and inter-unit variability. The largest range of uncertainty in the mean was obtained for the external coal combustion benzene emission factor, with 95 confidence interval of the mean equal to minus 93 to plus 411%.

Zhao, Y.C.; Frey, H.C. [CALTECH, Pasadena, CA (United States). Division of Chemical & Chemical Engineering

2006-12-15

147

Influence of Two-Stage Air Injection Conditions on NOx and Unburned Carbon of Sub-Bituminous Coal Combustion  

NASA Astrophysics Data System (ADS)

Because of large recoverable reserves, sub-bituminous coal is an important energy resources. The disadvantage of sub-bituminous coal is that it contains more than 20% moisture. This makes ignition less efficient. And combustion flame became diffused. Both emissions of NOx and unburned carbon in fly ash become high. We have already shown that these emissions can be reduced by adjusting the air injection conditions from the burner to better suit sub-bituminous coal combustion. However, the reduction is insufficient compared with bituminous coal combustion. In this investigation, influence of two-stage air injection conditions on NOx and unburned carbon concentration in fly ash was studied and the optimum air injection conditions necessary in order to reduce those emissions were clarified.

Ikeda, Michitaka; Makino, Hisao; Morinaga, Hideki; Higashiyama, Koichi

148

Calculating the parameters of self-oscillations in the vertical combustion chamber of the blast-furnace air heater during unstable combustion  

NASA Astrophysics Data System (ADS)

A procedure for simplified calculation of the parameters of self-oscillations excited during unstable (vibrating) combustion in the vertical combustion chambers of blast-furnace air heaters is developed. The proposed procedure is based on an independent nonlinear dynamic system similar to the equations from the theory of a blade supercharger stalling and surging mode. The head characteristic considered in the blade supercharger stalling and surging theory determines the part of the supercharger drive rotation energy that is converted into the head developed by the supercharger. In the considered system, the supercharger head characteristic is replaced by the combustion chamber head characteristic. Being a function of flow rate, this characteristic describes the part of heat supplied to flow that is converted to the flow head. Unlike the supercharger head characteristic, which is determined by experiment, the combustion chamber head characteristic is determined by calculation, due to which it becomes much easier to calculate the parameters of self-oscillations according to the proposed procedure. In particular, an analysis of the periodic solutions of the obtained dynamic system made it possible to determine the pattern in which the amplitude of considered self-oscillations depends on the surge impedance of the vertical combustion chamber.

Basok, B. I.; Gotsulenko, V. V.

2015-01-01

149

Effect of air-staging on mercury speciation in pulverized fuel co-combustion: part 2  

SciTech Connect

The concerns regarding global warming and need for new energy resources brought the concept of biomass and waste as secondary fuels to the power industry. Mercury emissions in cases of cofiring of chicken manure, olive residue, and B-wood with a high volatile bituminous coal blend are studied in the first part of this paper. The use of secondary fuels significantly affects NOx emissions due to different types of nitrogen present in the fuel matrix. Air-staging is a proven in-furnace NOx reduction technology. The present work mainly involves bench scale studies to investigate the effect of air-staging on partitioning of mercury in pulverized fuel co-combustion. The combustion experiments are carried out in an entrained flow reactor at 1300{sup o}C with a 20%th share of secondary fuels. Elemental and total gaseous mercury from the reactor is measured on-line, and ash is analyzed for particulate mercury along with elemental and surface properties. Reducing the air stoichiometry in the primary zone of the combustor increases unburnt carbon which in turn reduces mercury emissions in the gas phase. Ash analysis shows the effect of surface area, particle size, and unburnt carbon on mercury capture. Calcium variation in the ash was observed due to formation of different slag in reducing and oxidizing conditions and might have affected the mercury capture in combination with the above parameters. A low iron concentration of ash does not seem to affect the capture of mercury. The results will help in predicting different forms of mercury emitted from the furnace at desired operating conditions which will eventually form the basis for the design of the control strategies for mercury emissions. 22 refs., 3 figs., 1 tab.

Shishir P. Sable; Wiebren de Jong; Ruud Meij; Hartmut Spliethoff [Delft University Technology, Delft (Netherlands). Section Energy Technology, Department of Process and Energy

2007-08-15

150

Polychlorinated naphthalenes in Great lakes air: assessing spatial trends and combustion inputs using PUF disk passive air samplers.  

PubMed

Passive air samplers made from polyurethane foam (PUF) disks housed in stainless steel chambers were deployed over four seasons during 2002-2003, at 15 sites in the Laurentian Great lakes, to assess spatial and temporal trends of polychlorinated naphthalenes (PCNs). Sampling rates, determined using depuration compounds pre-spiked into the PUF disk prior to exposure, were, on average, 2.9 +/- 1.1 m3 d(-1), consistent with previous studies employing these samplers. PCN air concentrations exhibited strong urban-rural differences-typically a few pg m(-3) at rural sites and an order of magnitude higher at urban sites (Toronto, 12-31 pg m(-3) and Chicago,13-52 pg m(-3)). The high concentrations at urban sites were attributed to continued emissions of historically used technical PCN. Contributions from combustion-derived PCNs seemed to be more important at rural locations where congeners 24 and 50, associated with wood and coal burning, were elevated. Congener 66/67, associated with incineration and other industrial thermal processes, was elevated at two sites and explained by nearby and/or upwind sources. Probability density maps were constructed for each site and for every integration period were shown to be a useful complement to seasonally integrated passive sampling data to resolve source-receptor relationship for PCNs and other pollutants. PMID:16999107

Harner, Tom; Shoeib, Mahiba; Gouin, Todd; Blanchard, Pierrette

2006-09-01

151

Polychlorinated naphthalenes in Great Lakes air: assessing spatial trends and combustion inputs using PUF disk passive air samplers  

SciTech Connect

Passive air samplers made from polyurethane foam (PUF) disks housed in stainless steel chambers were deployed over four seasons during 2002-2003, at 15 sites in the Laurentian Great lakes, to assess spatial and temporal trends of polychlorinated naphthalenes (PCNs). Sampling rates, determined using depuration compounds pre-spiked into the PUF disk prior to exposure, were, on average, 2.9 {+-} 1.1 m{sup 3} d{sup -1}, consistent with previous studies employing these samplers. PCN air concentrations exhibited strong urban-rural differences - typically a few pg m{sup 3} at rural sites and an order of magnitude higher at urban sites (Toronto, 12-31 pg m{sup -3} and Chicago, 13-52 pg m{sup -3}). The high concentrations at urban sites were attributed to continued emissions of historically used technical PCN. Contributions from combustion-derived PCNs seemed to be more important at rural locations where congeners 24 and 50, associated with wood and coal burning, were elevated. Congener 66/67, associated with incineration and other industrial thermal processes, was elevated at two sites and explained by nearby and/or upwind sources. Probability density maps were constructed for each site and for every integration period were shown to be a useful complement to seasonally integrated passive sampling data to resolve source-receptor relationship for PCNs and other pollutants. 25 refs., 7 figs., 1 tabs.

Tom Harner; Mahiba Shoeib; Todd Gouin; Pierrette Blanchard [Environment Canada, Toronto, ON (Canada). Science & Technology Branch

2006-09-01

152

Simulating the Impact of Oxygen Enrichment in a Cement Rotary Kiln Using Advanced Computational Methods  

Microsoft Academic Search

This work presents the simulation of a rotary kiln used to produce cement clinker. The effort uses an original approach to kiln operation modeling. Thus, the moving cement clinker is accurately simulated, including exothermal reactions into the clicker and advanced heat transfer correlations. The simulation includes the normal operation of a cement kiln, using coal in an air-fired configuration. The

OVIDIU MARIN; OLIVIER CHARON; JACQUES DUGUE; SARAH DUKHAN; WEI ZHOU

2001-01-01

153

Opposed jet burner studies of hydrogen combustion with pure and N2, NO-contaminated air  

NASA Technical Reports Server (NTRS)

A counterflow diffusion flame formed by an argon-bathed tubular-opposed jet burner (OJB) was used to determine the 'blowoff' and 'restore' combustion characteristics for jets of various H2/N2 mixtures and for jets of air contaminated by NO (which normally occurs in high-enthalpy airflows supplied to hypersonic test facilities for scramjet combustors). Substantial divergence of 'blowoff' and 'restore' limits occurred as H2 mass flux, M(H)2, increased, the H2 jet became richer, and the M(air)/M(H2 + N2) ratio increased from 1 to 3 (molar H2/O2 from 1 to 16). Both OJB limits were sensitive to reactant composition. One to six percent NO in air led to significant N2-corrected decreases in the M(H2) values for 'blowoff' (2-8 percent) and 'restore' (6-12 percent) for mole fractions of H2 ranging from 0.5 to 0.95. However, when H2/O2 was held constant, all N2-corrected changes in M(H2) were negligible.

Guerra, Rosemary; Pellett, Gerald L.; Northam, G. Burton; Wilson, Lloyd G.

1987-01-01

154

An analytical study of the hydrogen-air reaction mechanism with application to scramjet combustion  

NASA Technical Reports Server (NTRS)

A chemical kinetic mechanism for the combustion of hydrogen has been assembled and optimized by comparing the observed behavior as determined in shock tube and flame studies with that predicted by the mechanism. The reactions contained in the mechanism reflect the current state of knowledge of the chemistry of the hydrogen/air system, and the assigned rate coefficients are consistent with accepted values. It was determined that the mechanism is capable of satisfactorily reproducing the experimental results for a range of conditions relevant to scramjet combustion. Calculations made with the reaction mechanism for representative scramjet combustor conditions at Mach 8, 16, and 25 showed that chemical kinetic effects can be important and that combustor models which use nonequilibrium chemistry should be used in preference to models that assume equilibrium chemistry. For the conditions examined the results also showed the importance of including the HO2 chemistry in the mechanism. For Mach numbers less than 16, the studies suggest that an ignition source will most likely be required to overcome slow ignition chemistry. At Mach 25, the initial temperature and pressure was high enough that ignition was rapid and the presence of an ignition source did not significantly affect reaction rates.

Jachimowski, Casimir J.

1988-01-01

155

Effects of EGR rate and excess air ratio on the combustion characteristics of compressed natural gas engine  

Microsoft Academic Search

The influence of EGR (exhaust gas recirculation) rate and excess air ratio (?) on the combustion and emissions of a twofold dilution compressed natural gas (CNG) engine CA6SE3-21E4N were investigated experimentally to solve the limited decreasing-ability on NOx emissions with air dilution. The results show that as EGR rate and ? increase, the peak of cylinder pressure and heat release

Xiao-cao Yu; Zhong-chang Liu; Zhong-shu Wang; Hui-li Dou

2011-01-01

156

Experimental investigations on the combustion behavior of methane air mixtures in a micro-scale radial combustor configuration  

Microsoft Academic Search

Experimental investigations on combustion stability limits for methane-air mixtures in a radial micro-scale combustor configuration are herein reported. To study the flame stability characteristics in this radial combustor configuration, two circular quartz plates were arranged parallel to each other and a fuel-air mixture was supplied at the center of the plates. The plates were externally heated to create a positive

Sudarshan Kumar; Kaoru Maruta; S. Minaev

2007-01-01

157

Review of Air Vitiation Effects on Scramjet Ignition and Flameholding Combustion Processes  

NASA Technical Reports Server (NTRS)

This paper offers a detailed review and analysis of more than 100 papers on the physics and chemistry of scramjet ignition and flameholding combustion processes, and the known effects of air vitiation on these processes. The paper attempts to explain vitiation effects in terms of known chemical kinetics and flame propagation phenomena. Scaling methodology is also examined, and a highly simplified Damkoehler scaling technique based on OH radical production/destruction is developed to extrapolate ground test results, affected by vitiation, to flight testing conditions. The long term goal of this effort is to help provide effective means for extrapolating ground test data to flight, and thus to reduce the time and expense of both ground and flight testing.

Pellett, G. L.; Bruno, Claudio; Chinitz, W.

2002-01-01

158

Nanosecond repetitively pulsed discharge control of premixed lean methane-air combustion  

NASA Astrophysics Data System (ADS)

Two-dimensional kinetic simulations are carried out to investigate the effects of the discharge repetition rate and pulse width of nanosecond repetitively pulsed discharges on stabilizing premixed lean methane-air combustion. The repetition rate and pulse widths are varied from 10 kHz to 50 kHz and from 9 ns to 2 ns respectively, while the total power is held constant. The lower repetition rates, because of their higher pulse energies, produce a larger fraction of radicals such as O, H, and OH. Surprisingly, however, the effect on flame stabilization is found to be essentially the same for all of the tested repetition rates. The shorter pulse width is found to favor the production of species in higher electronic states, but the varying effects on stabilization is also found to be small. Our results indicate that the total deposited power is the critical element that determines the extent of stabilization over this range of discharge properties studied.

Bak, Moon Soo; Cappelli, Mark A.

2012-10-01

159

Commercialization of Turbulent Combustion Code CREBCOM for Chemical Industry Safety  

SciTech Connect

This program developed the Kurchatov Institute’s CREBCOM (CRiteria and Experimentally Based COMbustion) code to the point where it could be commercialized and marketed for the special applications described above, as well as for general purpose combustion calculations. The CREBCOM code uses a different approach to model the explosion phenomenon. The code models, with full 3D gas dynamics, the development of an explosion in three characteristics regimes: a) slow flames, b) fast flames, and c) detonation. The transition from one regime to another is governed by a set of empirical criteria and correlations. As part of the commercialization, the code was validated with the use of experimental data. The experimental data covered a range of thermodynamic initial conditions and apparatus scale. Proprietary experimental data were provided to the Kurchatov Institute by the DuPont for this purpose. The flame acceleration and detonation data was obtained from experiments in methane and oxygen enriched air mixtures carried out in two vessels with diameters of 20 and 27 cm. The experimental data covers a wide spectrum of initial temperature (20-525C) and pressure (1-3 atm). As part of this program, the Kurchatov Institute performed experiments in a 52 cm vessel in mixtures of methane-air at room temperature and pressure to be used in the validation of the code. The objective of these tests was to obtain frame acceleration data at a scale close to that found in actual industrial processes. BNL was responsible for managing the DOE/IPP portion of the program, and for satisfying DOE reporting requirements. BNL also participated in an independent assessment of the CREBOM code. DuPont provided proprietary experimental data to the Kurchatov Institute on flame acceleration and detonation in high temperature methane and oxygen enriched air mixtures in addition to the matching fund. In addition, DuPont also supplied to KI instrumentation for pressure and temperature measurement. Kurchatov (KI) performed experiments at close to full-scale in mixtures of room temperature methane and air to develop the CREBCOM code which was used for explosion simulation in confined geometrics, such as chemical reactors and converters. The code was validated by comparison of the code simulations with experimental data obtained under prototypic reactor mixture conditions.

Rohatgi, Upendra

2007-06-30

160

Hybrid membrane--PSA system for separating oxygen from air  

DOEpatents

A portable, non-cryogenic, oxygen generation system capable of delivering oxygen gas at purities greater than 98% and flow rates of 15 L/min or more is described. The system consists of two major components. The first component is a high efficiency membrane capable of separating argon and a portion of the nitrogen content from air, yielding an oxygen-enriched permeate flow. This is then fed to the second component, a pressure swing adsorption (PSA) unit utilizing a commercially available, but specifically formulated zeolite compound to remove the remainder of the nitrogen from the flow. The system is a unique gas separation system that can operate at ambient temperatures, for producing high purity oxygen for various applications (medical, refining, chemical production, enhanced combustion, fuel cells, etc . . . ) and represents a significant advance compared to current technologies.

Staiger, Chad L. (Albuquerque, NM); Vaughn, Mark R. (Albuquerque, NM); Miller, A. Keith (Albuquerque, NM); Cornelius, Christopher J. (Blackburg, VA)

2011-01-25

161

Quantifying the impact of residential heating on the urban air quality in a typical European coal combustion region.  

PubMed

The present investigation, carried out as a case study in a typical major city situated in a European coal combustion region (Krakow, Poland), aims at quantifying the impact on the urban air quality of residential heating by coal combustion in comparison with other potential pollution sources such as power plants, industry, and traffic. Emissions were measured for 20 major sources, including small stoves and boilers, and the particulate matter (PM) was analyzed for 52 individual compounds together with outdoor and indoor PM10 collected during typical winter pollution episodes. The data were analyzed using chemical mass balance modeling (CMB) and constrained positive matrix factorization (CMF) yielding source apportionments for PM10, B(a)P, and other regulated air pollutants namely Cd, Ni, As, and Pb. The results are potentially very useful for planning abatement strategies in all areas of the world, where coal combustion in small appliances is significant. During the studied pollution episodes in Krakow, European air quality limits were exceeded with up to a factor 8 for PM10 and up to a factor 200 for B(a)P. The levels of these air pollutants were accompanied by high concentrations of azaarenes, known markers for inefficient coal combustion. The major culprit for the extreme pollution levels was demonstrated to be residential heating by coal combustion in small stoves and boilers (>50% for PM10 and >90% B(a)P), whereas road transport (<10% for PM10 and <3% for B(a)P), and industry (4-15% for PM10 and <6% for B(a)P) played a lesser role. The indoor PM10 and B(a)P concentrations were at high levels similar to those of outdoor concentrations and were found to have the same sources as outdoors. The inorganic secondary aerosol component of PM10 amounted to around 30%, which for a large part may be attributed to the industrial emission of the precursors SO2 and NOx. PMID:19921921

Junninen, Heikki; Mønster, Jacob; Rey, Maria; Cancelinha, Jose; Douglas, Kevin; Duane, Matthew; Forcina, Victtorio; Müller, Anne; Lagler, Fritz; Marelli, Luisa; Borowiak, Annette; Niedzialek, Joanna; Paradiz, Bostian; Mira-Salama, Daniel; Jimenez, Jose; Hansen, Ute; Astorga, Covadonga; Stanczyk, Krzysztof; Viana, Mar; Querol, Xavier; Duvall, Rachelle M; Norris, Gary A; Tsakovski, Stefan; Wåhlin, Peter; Horák, Jiri; Larsen, Bo R

2009-10-15

162

Simultaneous removal of SO{sub 2} and NO from flue gas using 'oxygen-enriched' highly reactive absorbent  

SciTech Connect

Fly ash, industry-grade lime, and an additive, MnO{sub 2} (M), were used to prepare an 'oxygen-enriched' highly reactive absorbent. Experiments of simultaneous desulfurization and denitrification were carried in a flue gas circulating fluidized bed (CFB). The effects of influencing factors were also investigated on the removal efficiencies of desulfurization and denitrification. Removal efficiencies of 95.5% for SO{sub 2} and 64.8% for NO were obtained respectively under the optimal experimental conditions. The component of the spent absorbent was analyzed with chemical analysis methods. The results indicated that more nitrogen species appeared in the spent absorbent except sulfur species. A scanning electron microscope (SEM) and an accessory X-ray energy spectrometer (EDS) were used to observe microproperties of the samples, including fly ash, oxidizing highly reactive absorbent, and spent absorbent. The simultaneous removal mechanism of SO{sub 2} and NO based on this absorbent was proposed according to the experimental results.

Zhao, Y.; Sun, X.J.; Fang, H.; Liu, F. [North China Electric Power University, Baoding (China). School for Environmental Science and Engineering

2007-04-15

163

Influence of specimen size, tray inclination and air flow rate on the emission of gases from biomass combustion  

NASA Astrophysics Data System (ADS)

Experiments of biomass combustion were performed to determine whether specimen size, tray inclination, or combustion air flow rate was the factor that most affects the emission of carbon dioxide, carbon monoxide, and methane. The chosen biomass was Eucalyptus citriodora, a very abundant species in Brazil, utilized in many industrial applications, including combustion for energy generation. Analyses by gas chromatograph and specific online instruments were used to determine the concentrations of the main emitted gases, and the following figures were found for the emission factors: 1400 ± 101 g kg-1 of CO2, 50 ± 13 g kg-1 of CO, and 3.2 ± 0.5 g kg-1 of CH4, which agree with values published in the literature for biomass from the Amazon rainforest. Statistical analysis of the experiments determined that specimen size most significantly affected the emission of gases, especially CO2 and CO.

Amorim, E. B.; Carvalho, J. A.; Soares Neto, T. G.; Anselmo, E.; Saito, V. O.; Dias, F. F.; Santos, J. C.

2013-08-01

164

A New Type of Steady and Stable, Laminar, Premixed Flame in Ultra-Lean, Hydrogen-Air Combustion  

SciTech Connect

Ultra-lean, hydrogen-air mixtures are found to support another kind of laminar flame that is steady and stable beside flat flames and flame balls. Direct numerical simulations are performed of flames that develop into steadily and stably propagating cells. These cells were the original meaning of the word"flamelet'' when they were observed in lean flammability studies conducted early in the development of combustion science. Several aspects of these two-dimensional flame cells are identified and are contrasted with the properties of one-dimensional flame balls and flat flames. Although lean hydrogen-air flames are subject to thermo-diffusive effects, in this case the result is to stabilize the flame rather than to render it unstable. The flame cells may be useful as basic components of engineering models for premixed combustion when the other types of idealized flames are inapplicable.

Grcar, Joseph F; Grcar, Joseph F

2008-06-30

165

Two dimensional, transient catalytic combustion of CO-air on platinum  

NASA Technical Reports Server (NTRS)

The light off transient of catalytic combustion of lean CO-air mixtures in a platinum coated channel of a honeycomb monolith is studied with a model that resolves transient radial and axial gradients in both the gas and the solid. For the conditions studied it is concluded that: the initial heat release occurs near the entrance at the gas-solid interface and is controlled by heterogeneous reactions; large spatial and temporal temperature gradients occur in the solid near the entrance controlled mostly by the availability of fuel; the temperature of the solid near the entrance achieves almost its steady state value before significant heating of the back; heterogeneous reactions and the gas heated up front and flowing downstream heat the back of the solid; the overall transient time is controlled by the thermal inertia of the solid and by forced convection; radiation significantly influences both transient and steady state particularly near the entrance; the oxidation of CO occurs mostly on the catalyst and becomes diffusion controlled soon into the transient.

Sinha, N.; Bruno, C.; Bracco, F. V.

1985-01-01

166

NO{sub x} emissions of a jet diffusion flame which is surrounded by a shroud of combustion air  

SciTech Connect

The present work reports an experimental study on the behavior of a jet flame surrounded by a shroud of combustion air. Measurements focussed on the flame length and the emissions of NO{sub x}, total unburned hydrocarbons, CO{sub 2}, and O{sub 2}. Four different fuel flow rates (40.0, 78.33, 138.33, and 166.6 cm/s), air flow rates up to 2500 cm{sup 3}/s and four different air injector diameters (0.079 cm, 0. 158 cm, 0.237 cm, and 0.316 cm) were used. The shroud of combustion air causes the flame length to decrease by a factor proportional to 1/[p{sub a}/p{sub f} + C{sub 2}({mu}{sub a}Re,a/{mu}{sub f}Re,f){sup 2}]{sup {1/2}}. A substantial shortening of the flame length occurred by increasing the air injection velocity keeping fuel rate fixed or conversely by lowering the fuel flow rate keeping air flow rate constant. NO{sub x} emissions ranging from 5 ppm to 64 ppm were observed and the emission of NO{sub x} decreased strongly with the increased air velocity. The decrease of NO{sub x} emissions was found to follow a similar scaling law as does the flame length. However, the emission of the total hydrocarbons increased with the increased air velocity or the decreased fuel flow rate. A crossover condition where both NO{sub x} and unburned- hydrocarbon emissions are low, was identified. At an air-to-fuel velocity ratio of about 1, the emissions of NO{sub x} and the total hydrocarbons were found to be under 20 ppm.

Tran, P.X.; White, F.P.; Mathur, M.P.; Ekmann, J.M.

1996-08-01

167

Mercury and Air Toxic Element Impacts of Coal Combustion By-Product Disposal and Utilizaton  

SciTech Connect

The University of North Dakota Energy & Environmental Research Center (EERC) conducted a multiyear study to evaluate the impact of mercury and other air toxic elements (ATEs) on the management of coal combustion by-products (CCBs). The ATEs evaluated in this project were arsenic, cadmium, chromium, lead, nickel, and selenium. The study included laboratory tasks to develop measurement techniques for mercury and ATE releases, sample characterization, and release experiments. A field task was also performed to measure mercury releases at a field site. Samples of fly ash and flue gas desulfurization (FGD) materials were collected preferentially from full-scale coal-fired power plants operating both without and with mercury control technologies in place. In some cases, samples from pilot- and bench-scale emission control tests were included in the laboratory studies. Several sets of 'paired' baseline and test fly ash and FGD materials collected during full-scale mercury emission control tests were also included in laboratory evaluations. Samples from mercury emission control tests all contained activated carbon (AC) and some also incorporated a sorbent-enhancing agent (EA). Laboratory release experiments focused on measuring releases of mercury under conditions designed to simulate CCB exposure to water, ambient-temperature air, elevated temperatures, and microbes in both wet and dry conditions. Results of laboratory evaluations indicated that: (1) Mercury and sometimes selenium are collected with AC used for mercury emission control and, therefore, present at higher concentrations than samples collected without mercury emission controls present. (2) Mercury is stable on CCBs collected from systems both without and with mercury emission controls present under most conditions tested, with the exception of vapor-phase releases of mercury exposed to elevated temperatures. (3) The presence of carbon either from added AC or from unburned coal can result in mercury being sorbed onto the CCB when exposed to ambient-temperature air. The environmental performance of the mercury captured on AC used as a sorbent for mercury emission control technologies indicated that current CCB management options will continue to be sufficiently protective of the environment, with the potential exception of exposure to elevated temperatures. The environmental performance of the other ATEs investigated indicated that current management options will be appropriate to the CCBs produced using AC in mercury emission controls.

David Hassett; Loreal Heebink; Debra Pflughoeft-Hassett; Tera Buckley; Erick Zacher; Mei Xin; Mae Sexauer Gustin; Rob Jung

2007-03-31

168

Waste combustion as a source of ambient air polybrominated diphenylethers (PBDEs)  

NASA Astrophysics Data System (ADS)

The first comprehensive set of U.S. data on polybrominated diphenylether (PBDE) concentrations from municipal waste combustion (MWC), with more than 40 PBDE congeners reported, was compared to ambient air levels of PBDEs in the U.S. The PBDE profiles in the raw MWC flue gas reflected the historical production and usage pattern of PBDE-based flame retardants in North America, which favored Penta- and Deca- BDE formulations. The pattern of selected, routinely measured in the environment, PBDEs (TeBDE-47, PeBDE-99, PeBDE-100, HxBDE-153 and DcBDE-209) was similar in the MWC emissions and profiles most commonly reported for the U.S. atmosphere. The mean ? PBDE concentrations in the clean flue gases collected from the stack were 0.13 and 1.7 ng dscm -1 during the steady state and transients of MWC, respectively (which was 98.6% reduction compare to the levels in the raw flue gases). The major PBDE congeners in the MWC flue gases were those typically found in PBDE technical mixes (TeBDE-47, PeBDE-99, PeBDE-100, HxBDE-153, HpBDE-183, OcBDE-197, NoBDE-206, NoBDE-207, NoBDE-208, DcBDE-209). The profile of the PBDEs in the raw flue gas was dominated by heavier congeners, especially DcBDE-209, while the profile of the stack flue gases profile was dominated by the lighter congeners (TeBDE-47, PeBDE-99, PeBDE-100 accounted for around 80% of total stack emissions). Some of the MWC flue gas samples exhibited enrichment of lower brominated congeners that are minor or not present in the technical mixtures, suggesting that debromination occurs during combustion. Congeners substituted in non- and mono- ortho positions (TeBDE-77, PeBDE-126, HxBDE-156 and -169) were detected mostly during the transients of MWC.

Wyrzykowska-Ceradini, Barbara; Gullett, Brian K.; Tabor, Dennis; Touati, Abderrahmane

2011-08-01

169

Enhanced Adhesion of Campylobacter jejuni to Abiotic Surfaces Is Mediated by Membrane Proteins in Oxygen-Enriched Conditions  

PubMed Central

Campylobacter jejuni is responsible for the major foodborne bacterial enteritis in humans. In contradiction with its fastidious growth requirements, this microaerobic pathogen can survive in aerobic food environments, suggesting that it must employ a variety of protection mechanisms to resist oxidative stress. For the first time, C. jejuni 81–176 inner and outer membrane subproteomes were analyzed separately using two-dimensional protein electrophoresis (2-DE) of oxygen-acclimated cells and microaerobically grown cells. LC-MS/MS analyses successfully identified 42 and 25 spots which exhibited a significantly altered abundance in the IMP-enriched fraction and in the OMP-enriched fraction, respectively, in response to oxidative conditions. These spots corresponded to 38 membrane proteins that could be grouped into different functional classes: (i) transporters, (ii) chaperones, (iii) fatty acid metabolism, (iv) adhesion/virulence and (v) other metabolisms. Some of these proteins were up-regulated at the transcriptional level in oxygen-acclimated cells as confirmed by qRT-PCR. Downstream analyses revealed that adhesion of C. jejuni to inert surfaces and swarming motility were enhanced in oxygen-acclimated cells or paraquat-stressed cells, which could be explained by the higher abundance of membrane proteins involved in adhesion and biofilm formation. The virulence factor CadF, over-expressed in the outer membrane of oxygen-acclimated cells, contributes to the complex process of C. jejuni adhesion to inert surfaces as revealed by a reduction in the capability of C. jejuni 81–176 ?CadF cells compared to the isogenic strain. Taken together, these data demonstrate that oxygen-enriched conditions promote the over-expression of membrane proteins involved in both the biofilm initiation and virulence of C. jejuni. PMID:23029510

Sulaeman, Sheiam; Hernould, Mathieu; Schaumann, Annick; Coquet, Laurent; Bolla, Jean-Michel; Dé, Emmanuelle; Tresse, Odile

2012-01-01

170

CHARACTERIZATION OF AIR EMISSIONS FROM THE SIMULATED OPEN COMBUSTION OF FIBERGLASS MATERIALS  

EPA Science Inventory

The report identifies and quantifies a broad range of pollutants that are discharged during small-scale, simulated, open combustion of fiberglass, and reports these emissions relative to the mass of fiberglass material combusted. wo types of fiberglass materials (representing the...

171

CHARACTERIZATION OF AIR EMISSIONS FROM THE SIMULATED OPEN COMBUSTION OF FIBERGLASS MATERIALS  

EPA Science Inventory

The report identifies and quantifies a broad range of pollutants that are discharged during small-scale, simulated, open combustion of fiberglass, and reports these emissions relative to the mass of fiberglass material combusted. Two types of fiberglass materials (representing t...

172

External combustion rotary engine  

Microsoft Academic Search

A rotary piston external combustion engine is described comprising: means for compressing air and expanding combusted gas; a shaft connected to the compressing and expanding means for delivering power by means of an external drive shaft; an air inlet port opening for admitting ambient air in the air compressing means; an outlet valve for venting the compressed air out when

1988-01-01

173

Model test on underground coal gasification (UCG) with low-pressure fire seepage push-through. Part I: Test conditions and air fire seepage  

SciTech Connect

The technology of a pushing-through gallery with oxygen-enriched fire-seepage combustion was studied during shaft-free UCG in this article, and the main experiment parameters were probed. The test results were analyzed in depth. The patterns of variation and development were pointed out for the fire source moving speed, temperature field, leakage rate, the expanding diameter for the gasification gallery, and blasting pressure. Test results showed that, with the increase in the wind-blasting volume, the moving velocity for the fire source speeded up, and the average temperature for the gallery continuously rose. Under the condition of oxygen-enriched air blasting, when O{sub 2} contents stood at 90%, the moving speed for the fire source was 4-5 times that of air blasting. In the push-through process, the average leakage rate for the blasting was 82.23%, with the average discharge volume of 3.43 m{sup 3}/h and average gallery diameter of 7.87 cm. With the proceeding of firepower seepage, the extent of dropping for the leakage rate increased rapidly, and the drop rate for the blasting pressure gradually heightened.

Yang, L.H. [China University of Mining & Technology, Xuzhou (China)

2008-07-01

174

78 FR 14457 - National Emission Standards for Hazardous Air Pollutants for Reciprocating Internal Combustion...  

Federal Register 2010, 2011, 2012, 2013, 2014

...New Source Performance Standards for Stationary Internal Combustion Engines Correction...Requirements for Existing Compression Ignition Stationary RICE Located at a Major Source of HAP Emissions and Existing Spark Ignition Stationary RICE...

2013-03-06

175

Development of the utilization of combustible gas produced in existing sanitary landfills: Investigation of effects of air inclusion  

NASA Astrophysics Data System (ADS)

The effects of nitrogen and oxygen on landfill gas operations are discussed. A combustible gas mixture composed of methane and carbon dioxide is generated in municipal solid waste landfills. A consequence of the collection of this fuel gas is the inclusion of some air in the collected product. The effects include increased collected and purification costs, reduction in the quality of the fuel gas produced, corrosion, explosion hazards, and interference with odorant systems. The scope of such effects was determined by using landfill data of a gas recovery site as a basis. Useful supplemental fuel gas may be recovered despite the inclusion of air. Recommendations are made for establishing limits for nitrogen and oxygen content and minimizing the costs associated with their presence.

1983-01-01

176

Spray combustion and emissions in a direct-injection two stroke engine with wall-stabilization of an air-assisted spray  

Microsoft Academic Search

Previous experiments using an air-assisted spray in a impinge two-stroke direct-injected engine demonstrated a significant improvement in combustion stability at part-load conditions when a wide injection spray was used. It was hypothesized caused that the decrease in variability was due to the spray following the combustion chamber wall, making it less affected by variations in the in-cylinder gas flows. For

M. V. Casarella; M. L. Syvertsen; J. K. Martin; J. A. Hoffman; J. B. Ghandhi

1997-01-01

177

Influence of Gravity and Ambient Pressure on Combustion and Flammability of n-Heptane and 1Propanol Droplets in Air-Diluent Environments  

Microsoft Academic Search

Reduced gravity and normal gravity combustion experiments were performed with individual fiber-supported n-heptane and 1-propanol droplets with initial diameters in the 1-mm size range. Experiments were performed with air-inert mixtures at 0.1 MPa or 0.3 MPa and about 298 K, where helium, carbon dioxide, or xenon were separately used as inerts. The amount of inert gas required to suppress combustion was generally higher

B. D. Shaw; J. B. Wei

2011-01-01

178

Tracer-based laser-induced fluorescence measurement technique for quantitative fuel/air-ratio measurements in a hydrogen internal combustion engine.  

PubMed

A measurement technique for the quantitative investigation of mixture formation processes in hydrogen internal combustion engines (ICEs) has been developed using tracer-based laser-induced fluorescence (TLIF). This technique can be employed to fired and motored engine operation. The quantitative TLIF fuel/air-ratio results have been verified by means of linear Raman scattering measurements. Exemplary results of the simultaneous investigation of mixture formation and combustion obtained at an optical accessible hydrogen ICE are shown. PMID:19079454

Blotevogel, Thomas; Hartmann, Matthias; Rottengruber, Hermann; Leipertz, Alfred

2008-12-10

179

Numerical simulation of air and oxy-fuel combustion of single coal particles using the reactive implicit continuous-fluid Eulerian (RICE) method  

NASA Astrophysics Data System (ADS)

The paper presents the mathematical model of air and oxy-fuel combustion of single coal particles. The combustion process has been treated as a spherically-symmetric one. The 1-dimensional time-dependent conservation equations governing the process have been numerically solved using the RICE method. The presence of a coal particle, which was treated as a discrete Lagrange particle, has modified the boundary conditions at the gas-solid interface. Numerical results show good agreement with the experimental results.

Lewtak, Robert

2013-10-01

180

Combustion Control  

E-print Network

casing of the fuel control regulator with the combustion air piping. The upstream pressure on the burner air orifice is applied to the main diaphragm of the pressure balanced regulator. Assuming sufficient gas pressure at the regulator inlet..., the outlet gas pressure will equal the air impulse pressLre. As the primary control drive moves to open or close the air valve, the outlet pressure will "track" changes in air pressure. The burner is an orifice for the air (assuming that it is in good...

Riccardi, R. C.

1984-01-01

181

Spatially and Temporally Resolved Measurements of Velocity in a H2-air Combustion-Heated Supersonic Jet  

NASA Technical Reports Server (NTRS)

This paper presents simultaneous measurements at multiple points of two orthogonal components of flow velocity using a single-shot interferometric Rayleigh scattering (IRS) technique. The measurements are performed on a large-scale Mach 1.6 (Mach 5.5 enthalpy) H2-air combustion jet during the 2007 test campaign in the Direct Connect Supersonic Combustion Test facility at NASA Langley Research Center. The measurements are performed simultaneously with CARS (Coherent Anti-stokes Raman Spectroscopy) using a combined CARS-IRS instrument with a common path 9-nanosecond pulsed, injection-seeded, 532-nm Nd:YAG laser probe pulse. The paper summarizes the measurements of velocities along the core of the vitiated air flow as well as two radial profiles. The average velocity measurement near the centerline at the closest point from the nozzle exit compares favorably with the CFD calculations using the VULCAN code. Further downstream, the measured axial velocity shows overall higher values than predicted with a trend of convergence at further distances. Larger discrepancies are shown in the radial profiles.

Bivolaru, Daniel; Cutler, Andrew D.; Danehy, Paul M.; Gaffney, Richard L.; Baurle, Robert a.

2009-01-01

182

Numerical study of combustion initiation in a supersonic flow of H2-air mixture by resonance laser radiation  

NASA Astrophysics Data System (ADS)

A comparative analysis of the efficiency of approaches based on the exposure of reacting gas to resonance laser radiation to enhance combustion in a supersonic flow of H2-air mixture is conducted. The kinetic processes responsible for the intensification of chain reactions in premixed and non-premixed H2-air flows upon photodissociation of O2 molecules by 193.3 nm laser radiation, excitation of these molecules to the singlet sigma state by laser photons with 762.346 nm wavelength and heating the mixture by laser radiation are analysed in a detailed manner. It is shown that both photochemical methods, photodissociation and excitation of O2 molecules, are much more effective in shortening the ignition delay length than merely heating the mixture. For the premixed flow, the photodissociation of O2 molecules ensures a slightly higher reduction in the ignition delay than the laser-induced excitation of molecular oxygen to the singlet sigma state. However, in the non-premixed flow the situation is inverted. The analysis shows that both photochemical methods make it possible to raise the efficiency of conversion of reactant chemical energy to thermal energy released during combustion compared with the method of heating the mixtures.

Bezgin, L. V.; Kopchenov, V. I.; Kuleshov, P. S.; Titova, N. S.; Starik, A. M.

2012-02-01

183

Exposure risk to carcinogenic PAHs in indoor-air during biomass combustion whilst cooking in rural India  

NASA Astrophysics Data System (ADS)

In India, a vast majority of rural household burns unprocessed biomass, as an energy source, to cook food. The biomass is burnt indoors in conventionally homemade clay-stoves, called 'Chulha', which results in the generation of a variety of airborne products along with polycyclic aromatic hydrocarbons (PAHs) in an uncontrolled manner. We report here the concentrations and profile of carcinogenic PAHs, co-sampled with respirable suspended particulate matter, in rural indoors during burning of biomass vis-à-vis liquified petroleum gas as the energy source. There is a limited data on the subject in the literature. The seasonal variation has also been studied. Sampling was done in breathing zone and in surrounding areas concurrent with cooking on chulha. PAHs were extracted in methylene chloride and analyzed over HPLC after column clean up on silica gel. Our study revealed that the concentrations of carcinogenic PAHs were fairly high in breathing zone and in surrounding areas while cooking over chulha in rural India. PAHs concentrations increased substantially during biomass combustion. Concentrations were high during CDC combustion and low during LPG combustion or the non-cooking period. This trend was conserved in both the seasons. Concentrations of total PAHs were greater in winter as compared to summer and greatest in the breathing zone. Di-benz( a,h)anthracene, benzo( k)-fluoranthene and chrysene contributed maximum. Benzo( a)pyrene contributed moderately. Maximum concentrations of indoor air benzo( a)pyrene (>1.5 ?g/m 3) were found in breathing zone in winter. The daily exposure to high concentrations of carcinogenic PAHs in indoor air environment while cooking food could be impacting for chronic pulmonary illnesses in rural Indian women.

Bhargava, Anuj; Khanna, R. N.; Bhargava, S. K.; Kumar, Sushil

184

ENVIRONMENTAL CONTROL OF TOXIC METAL AIR EMISSIONS FROM THE COMBUSTION OF COAL AND WASTES  

EPA Science Inventory

The paper is concerned with the partitioning of toxic metals (e.g., arsenic, selenium, mercury, chromium, lead, and cadmium) during combustion, and with the mitigation of their effect on the environment using high-temperature sorbents. The paper is divided into three parts: (1) t...

185

Combustion Measurements in Air Breathing Propulsion Engines. Survey and Research Needs  

Microsoft Academic Search

—The current measurement needs of the jet engine combustion engineers and scientists are considered. An assessment is made of the potential of probe and optical technologies to meet them.In the first part, the available instrumentation are evaluated and compared for the following criteria: non-interfering access to the flow, specificity, accuracy, sensitivity, space and time resolution, and cost effectiveness. The flow

R. GOULARD; A. M. MELLOR; R. W. BILGER

1976-01-01

186

Air toxics evaluation of ABB Combustion Engineering Low-Emission Boiler Systems  

SciTech Connect

The specific goals of the program are to identify air toxic compounds that might be emmitted from the new boiler with its various Air Pollution Control device for APCD alternatives in levels of regulatory concern. For the compounds thought to be of concern, potential air toxic control methodologies will be suggested and a Test Protocol will be written to be used in the Proof of Concept and full scale tests. The following task was defined: Define Replations and Standards; Identify Air Toxic Pollutants of Interest to Interest to Utility Boilers; Assesment of Air Toxic By-Products; State of the Art Assessment of Toxic By-Product Control Technologies; and Test Protocol Definition.

Wesnor, J.D. [ABB/Combustion Engineering, Inc., Windsor, CT (United States)

1993-10-26

187

CONTROL OF AIR EMISSIONS FROM HAZARDOUS WASTE COMBUSTION SOURCES: FIELD EVALUATIONS OF PILOT-SCALE AIR POLLUTION CONTROL DEVICES  

EPA Science Inventory

Pilot scale air pollution control devices supplied by Hydro-Sonic Systems, ETS, Inc., and Vulcan Engineering Company were installed at the ENSCO, Inc. Incinerator in El Dorado, Arkansas, in the spring of 1984. Each of these units treated an uncontrolled slipstream of the incinera...

188

Effect of Indoor air pollution from biomass and solid fuel combustion on symptoms of preeclampsia/eclampsia in Indian women.  

PubMed

Available evidence concerning the association between indoor air pollution (IAP) from biomass and solid fuel combustion and preeclampsia/eclampsia is not available in developing countries. We investigated the association between exposure to IAP from biomass and solid fuel combustion and symptoms of preeclampsia/eclampsia in Indian women by analyzing cross-sectional data from India's third National Family Health Survey (NFHS-3, 2005-2006). Self-reported symptoms of preeclampsia/eclampsia during pregnancy such as convulsions (not from fever), swelling of legs, body or face, excessive fatigue or vision difficulty during daylight, were obtained from 39 657 women aged 15-49 years who had a live birth in the previous 5 years. Effects of exposure to cooking smoke, ascertained by type of fuel used for cooking on preeclampsia/eclampsia risk, were estimated using logistic regression after adjusting for various confounders. Results indicate that women living in households using biomass and solid fuels have two times higher likelihood of reporting preeclampsia/eclampsia symptoms than do those living in households using cleaner fuels (OR = 2.21; 95%: 1.26-3.87; P = 0.006), even after controlling for the effects of a number of potentially confounding factors. This study is the first to empirically estimate the associations of IAP from biomass and solid fuel combustion and reported symptoms suggestive of preeclampsia/eclampsia in a large nationally representative sample of Indian women and we observed increased risk. These findings have important program and policy implications for countries such as India, where large proportions of the population rely on polluting biomass fuels for cooking and space heating. More epidemiological research with detailed exposure assessments and clinical measures of preeclampsia/eclampsia is needed in a developing country setting to validate these findings. PMID:25039812

Agrawal, S; Yamamoto, S

2014-07-15

189

System for feedback control of air-fuel mixing ratio in intake system of internal combustion engine  

SciTech Connect

A feedback control system using an oxygen-sensitive air/fuel ratio sensor which is disposed in induction passage for an ic engine downstream of a fuel supply device with the provision of an ignition means to burn a fractional portion of an air-fuel mixture in the induction passage such that the oxygen-sensitive sensor is exposed to a resultant combustion gas. The sensor is of the concentration cell type having a layer of solid electrolyte such as zirconia provided with two electrode layers, and constant dc current is supplied to this sensor to cause migration of oxygen ions through the solid electrolyte layer, whereby this sensor exhibits a slope output characteristic and can detect air/fuel ratios either above or below a stoichiometric ratio or exhibits an on-off characteristic and can detect the stoichiometric ratio depending on the intensity and flow direction of the current. Owing to reduced overall length of the closed-loop, this control system can accomplish correction of a deviated mixing ratio in a shortened period of time.

Masaki, K.; Sone, K.; Takase, S.

1982-11-23

190

Modeling of turbulent supersonic H2-air combustion with a multivariate beta PDF  

NASA Technical Reports Server (NTRS)

Recent calculations of turbulent supersonic reacting shear flows using an assumed multivariate beta PDF (probability density function) resulted in reduced production rates and a delay in the onset of combustion. This result is not consistent with available measurements. The present research explores two possible reasons for this behavior: use of PDF's that do not yield Favre averaged quantities, and the gradient diffusion assumption. A new multivariate beta PDF involving species densities is introduced which makes it possible to compute Favre averaged mass fractions. However, using this PDF did not improve comparisons with experiment. A countergradient diffusion model is then introduced. Preliminary calculations suggest this to be the cause of the discrepancy.

Baurle, R. A.; Hassan, H. A.

1993-01-01

191

Combustion Tests of Rocket Motor Washout Material: Focus on Air toxics Formation Potential and Asbestos Remediation  

SciTech Connect

The objective of this investigation is to determine the suitability of cofiring as a recycle / reuse option to landfill disposal for solid rocket motor washout residue. Solid rocket motor washout residue (roughly 55% aluminum powder, 40% polybutadiene rubber binder, 5% residual ammonium perchlorate, and 0.2-1% asbestos) has been fired in Sandia's MultiFuel Combustor (MFC). The MFC is a down-fired combustor with electrically heated walls, capable of simulating a wide range of fuel residence times and stoichiometries. This study reports on the fate of AP-based chlorine and asbestos from the residue following combustion.

G. C. Sclippa; L. L. Baxter; S. G. Buckley

1999-02-01

192

VITRIFICATION OF MUNICIPAL SOLID WASTE COMBUSTION AIR POLLUTION CONTROL RESIDUES USING CORNING, INC. PROCESS  

EPA Science Inventory

A demonstration was conducted to vitrify municipal solid waste (MSW) combustor air pollution control residue (APC) under the USEPA Municipal Waste Innovative Technology Evaluation Program. uplicate demonstration was conducted using a process developed by Corning Inc. in a cold cr...

193

Effects of combustion derived air pollution on vascular and fibrinolytic function in man   

E-print Network

Observational studies have consistently demonstrated associations between exposure to air pollution and increased cardiovascular morbidity and mortality. These associations are strongest for fine particulate matter (PM), of which particulates from...

Mills, Nicholas Linton

2009-01-01

194

Mapping the time-averaged distribution of combustion-derived air pollutants in the San Francisco Bay Area  

NASA Astrophysics Data System (ADS)

Urban air pollution is an ongoing and complicated problem for both residents and policy makers. This study aims to provide a better understanding of the geographic source and fate of organic pollutants in a dynamic urban environment. Natural and artificial hydrophobic substrates were employed for the passive monitoring and mapping of ground-level organic pollutants in the San Francisco Bay area. We focused specifically on volatile and semi-volatile polycyclic aromatic hydrocarbons (PAHs). These compounds are proxies for a broad range of combustion related air pollutants derived from local, regional, and global combustion sources. PAHs include several well-studied carcinogens and can be measured easily and accurately across a broad range of concentrations. Estimates of time-integrated vapor phase and particle deposition were made from measuring accumulated PAHs in the leaves of several widely distributed tree species (including the Quercus agrifolia and Sequoia sempervirens) and an artificial wax film. Samples were designed to represent pollutant exposure over a period of one to several months. The selective sampling and analysis of hydrophobic substrates providess insight into the average geographic distribution of ground-level air pollutants in a simple and inexpensive way. However, accumulated organics do not directly correlated with human exposure and the source signature of PAHs may be obscured by transport, deposition, and flux processes. We attempted to address some of these complications by studying 1) PAH accumulation rates within substrates in a controlled microcosm, 2) differences in PAH abundance in different substrate types at the same locality, and 3) samples near long-term high volume air sampling stations. We also set out to create a map of PAH concentrations based on our measurements. This map can be directly compared with interpolated data from high-volume sampling stations and used to address questions concerning atmospheric heterogeneity of these pollutants (i.e. due to both source localization and dominant wind patterns). Our initial results indicate that exposure to PAHs in the bay area is geographically heterogeneous and individual exposure may vary by more than two orders of magnitude. The signatures of PAH contamination also varies considerably, indicating different sources and differing transportation mechanisms may be important at different sites and times.

Yu, C.; Zinniker, D. A.; Moldowan, J.

2010-12-01

195

Parametric study of shock-induced combustion in a hydrogen air system  

NASA Technical Reports Server (NTRS)

A numerical parametric study is conducted to simulate shock-induced combustion under various free-stream conditions and varying blunt body diameter. A steady combustion front is established if the free-stream Mach number is above the Chapman-Jouguet speed of the mixture, whereas an unsteady reaction front is established if the free-stream Mach number is below or at the Chapman-Jouguet speed of the mixture. The above two cases have been simulated for Mach 5.11 and Mach 6.46 with a projectile diameter of 15 mm. Mach 5.11, which is an underdriven case, shows an unsteady reaction front, whereas Mach 6.46, which is an overdriven case, shows a steady reaction front. Next for Mach 5. 11 reducing the diameter to 2.5 mm causes the instabilities to disappear, whereas, for Mach 6.46 increasing the diameter of the projectile to 225 mm causes the instabilities to reappear, indicating that Chapman-Jouguet speed is not the only deciding factor for these instabilities to trigger. The other key parameters are the projectile diameter, induction time, activation energy and the heat release. The appearance and disappearance of the instabilities have been explained by the one-dimensional wave interaction model.

Ahuja, J. K.; Tiwari, Surendra N.

1994-01-01

196

Combustion rate limits of hydrogen plus hydrocarbon fuel: air diffusion flames from an opposed jet burner technique  

SciTech Connect

Combustion of H/sub 2//hydrocarbon (HC) fuel mixtures may be considered in certain volume-limited supersonic airbreathing propulsion applications. Effects of HC addition to H/sub 2/ were evaluated, using a recent argon-bathed, coaxial, tubular opposed jet burner (OJB) technique to measure the extinction limits of counterflow diffusion flames. The OJB flames were formed by a laminar jet of (N/sub 2/ and/or HC)-diluted H/sub 2/ mixture opposed by a similar jet of air at ambient conditions. The OJB data, derived from respective binary mixtures of H/sub 2/ and methane, ethylene, or propane HCs, were used to characterize BLOWOFF and RESTORE. BLOWOFF is a sudden breaking of the dish-shaped OJB flame to a stable torus or ring shape, and RESTORE marks sudden restoration of the central flame by radial inward flame propagation. BLOWOFF is a measure of kinetically-limited flame reactivity/speed under highly stretched, but relatively ideal impingement flow conditions. RESTORE measures inward radial flame propagation rate, which is sensitive to ignition processes in the cool central core. It is concluded that relatively small molar amounts of added HC greatly reduce the reactivity characteristics of counterflow hydrogen-air diffusion flames, for ambient initial conditions.

Pellett, G.L.; Guerra, R.; Wilson, L.G.; Reeves, R.N.; Northam, G.B.

1987-01-01

197

Combustion rate limits of hydrogen plus hydrocarbon fuel: Air diffusion flames from an opposed jet burner technique  

NASA Technical Reports Server (NTRS)

Combustion of H2/hydrocarbon (HC) fuel mixtures may be considered in certain volume-limited supersonic airbreathing propulsion applications. Effects of HC addition to H2 were evaluated, using a recent argon-bathed, coaxial, tubular opposed jet burner (OJB) technique to measure the extinction limits of counterflow diffusion flames. The OJB flames were formed by a laminar jet of (N2 and/or HC)-diluted H2 mixture opposed by a similar jet of air at ambient conditions. The OJB data, derived from respective binary mixtures of H2 and methane, ethylene, or propane HCs, were used to characterize BLOWOFF and RESTORE. BLOWOFF is a sudden breaking of the dish-shaped OJB flame to a stable torus or ring shape, and RESTORE marks sudden restoration of the central flame by radial inward flame propagation. BLOWOFF is a measure of kinetically-limited flame reactivity/speed under highly stretched, but relatively ideal impingement flow conditions. RESTORE measures inward radial flame propagation rate, which is sensitive to ignition processes in the cool central core. It is concluded that relatively small molar amounts of added HC greatly reduce the reactivity characteristics of counterflow hydrogen-air diffusion flames, for ambient initial conditions.

Pellett, Gerald L.; Guerra, Rosemary; Wilson, Lloyd G.; Reeves, Ronald N.; Northam, G. Burton

1987-01-01

198

BOOK REVIEW: Turbulent Combustion  

Microsoft Academic Search

The book Turbulent Combustion by Norbert Peters is a concise monograph on single-phase gaseous low Mach number turbulent combustion. It is compiled from the author's review papers on this topic plus some additional material. Norbert Peters characterizes turbulent combustion both by the way fuel and air are mixed and by the ratio of turbulent and chemical time scales. This approach

Norbert Peters

2001-01-01

199

Adiabatic internal combustion engine  

Microsoft Academic Search

An adiabatic internal combustion engine is described comprising a cylinder having a piston movably disposed therein, means for admitting air and fuel to the cylinder to be combusted therein and means for discharging the combustion gases therefrom, the cylinder including a piston guide and seal structure having stationary seal rings associated therewith and, the cylinder having an inner wall structure

C. E. Kraus; C. B. Lohr

1989-01-01

200

Research Opportunities for Cancer Associated with Indoor Air Pollution from Solid-Fuel Combustion  

EPA Science Inventory

Background: Indoor air pollution (IAP) derived largely from the use of solid fuels for cooking and heating affects about 3 billion people worldwide, resulting in substantial adverse health outcomes, including cancer. Women and children from developing countries are the most expos...

201

INDOOR AIR SAMPLING AND MUTAGENICITY STUDIES RELATED TO EMISSIONS FROM UNVENTED COAL COMBUSTION  

EPA Science Inventory

The purpose of the study is to develop sampling strategies and bioassay methods for indoor air in homes. The work reported here was conducted to prepare for a joint U.S.-China field study in Xuan Wei County, Yunnan Province, southern China, where the residents traditionally burn ...

202

Combustion & Health  

E-print Network

FFCOMBUSTION & HEALTH Winifred J. Hamilton, PhD, SM Clear Air Through Energy Efficiency (CATEE) Galveston, TX October 9?11, 2012 FFCOMBUSTION & HEALTH FFCOMBUSTION: THE THREAT ? Biggest threat to world ecosystems (and to human health...) ? Combustion of fossil fuels for ? Electricity ? Industrial processes ? Vehicle propulsion ? Cooking and heat ? Other ? Munitions ? Fireworks ? Light ? Cigarettes, hookahs? FFCOMBUSTION & HEALTH FFCOMBUSTION: THE THREAT ? SCALE (think health...

Hamilton, W.

2012-01-01

203

Combustion and NOx emission characteristics with respect to staged-air damper opening in a 600 MWe down-fired pulverized-coal furnace under deep-air-staging conditions.  

PubMed

Deep-air-staging combustion conditions, widely used in tangential-fired and wall-arranged furnaces to significantly reduce NOx emissions, are premature up to now in down-fired furnaces that are designed especially for industry firing low-volatile coals such as anthracite and lean coal. To uncover combustion and NOx emission characteristics under deep-air-staging conditions within a newly operated 600 MWe down-fired furnace and simultaneously understand the staged-air effect on the furnace performance, full-load industrial-size measurements taken of gas temperatures and species concentrations in the furnace, CO and NOx emissions in flue gas, and carbon in fly ash were performed at various staged-air damper openings of 10%, 20%, 30%, and 50%. Increasing the staged-air damper opening, gas temperatures along the flame travel (before the flame penetrating the staged-air zone) increased initially but then decreased, while those in the staged-air zone and the upper part of the hopper continuously decreased and increased, respectively. On opening the staged-air damper to further deepen the air-staging conditions, O2 content initially decreased but then increased in both two near-wall regions affected by secondary air and staged air, respectively, whereas CO content in both two regions initially increased but then decreased. In contrast to the conventional understanding about the effects of deep-air-staging conditions, here increasing the staged-air damper opening to deepen the air-staging conditions essentially decreased the exhaust gas temperature and carbon in fly ash and simultaneously increased both NOx emissions and boiler efficiency. In light of apparently low NOx emissions and high carbon in fly ash (i.e., 696-878 mg/m(3) at 6% O2 and 9.81-13.05%, respectively) developing in the down-fired furnace under the present deep-air-staging conditions, further adjustments such as enlarging the staged-air declination angle to prolong pulverized-coal residence times in the furnace should be considered to improve the deep-air-staging combustion configuration. PMID:24274316

Kuang, Min; Li, Zhengqi; Wang, Zhihua; Jing, Xinjing; Liu, Chunlong; Zhu, Qunyi; Ling, Zhongqian

2014-01-01

204

Combustion Characteristics of Pulverized Coal and Air\\/Gas Premixed Flame in a Double Swirl Combustor  

Microsoft Academic Search

An experimental work was performed to investigate the co-firing of pulverized coal and premixed gas\\/air streams in a double swirl combustor. The results showed that the NOx emissions are affected by the relative rates of thermal NOx formation and destruction via the pyrolysis of the fuel-N species in high temperature fuel-rich zones. Various burner designs were tested in order to

M. M. Kamal

2008-01-01

205

Intra-urban spatial variability in wintertime street-level concentrations of multiple combustion-related air pollutants: the New York City Community Air Survey (NYCCAS).  

PubMed

Although intra-urban air pollution differs by season, few monitoring networks provide adequate geographic density and year-round coverage to fully characterize seasonal patterns. Here, we report winter intra-urban monitoring and land-use regression (LUR) results from the New York City Community Air Survey (NYCCAS). Two-week integrated samples of fine particles (PM(2.5)), black carbon (BC), nitrogen oxides (NO(x)) and sulfur dioxide (SO(2)) were collected at 155 city-wide street-level locations during winter 2008-2009. Sites were selected using stratified random sampling, randomized across sampling sessions to minimize spatio-temporal confounding. LUR was used to identify GIS-based source indicators associated with higher concentrations. Prediction surfaces were produced using kriging with external drift. Each pollutant varied twofold or more across sites, with higher concentrations near midtown Manhattan. All pollutants were positively correlated, particularly PM(2.5) and BC (Spearman's r=0.84). Density of oil-burning boilers, total and truck traffic density, and temporality explained 84% of PM(2.5) variation. Densities of total traffic, truck traffic, oil-burning boilers and industrial space, with temporality, explained 65% of BC variation. Temporality, built space, bus route location, and traffic density described 67% of nitrogen dioxide variation. Residual oil-burning units, nighttime population and temporality explained 77% of SO(2) variation. Spatial variation in combustion-related pollutants in New York City was strongly associated with oil-burning and traffic density. Chronic exposure disparities and unique local sources can be identified through year-round saturation monitoring. PMID:23361442

Clougherty, Jane E; Kheirbek, Iyad; Eisl, Holger M; Ross, Zev; Pezeshki, Grant; Gorczynski, John E; Johnson, Sarah; Markowitz, Steven; Kass, Daniel; Matte, Thomas

2013-01-01

206

Air-substrate mercury exchange associated with landfill disposal of coal combustion products  

SciTech Connect

Previous laboratory studies have shown that lignite-derived fly ash emitted mercury (Hg) to the atmosphere, whereas bituminous- and subbituminous-derived fly ash samples adsorbed Hg from the air. In addition, wet flue gas desulfurization (FGD) materials were found to have higher Hg emission rates than fly ash. This study investigated in situ Hg emissions at a blended bituminous-subbituminous ash land-fill in the Great Lakes area and a lignite-derived ash and FGD solids landfill in the Midwestern United States using a dynamic field chamber. Fly ash and saturated FGD materials emitted Hg to atmosphere at low rates (- 0.1 to 1.2 ng/m{sup 2}hr), whereas FGD material mixed with fly ash and pyrite exhibited higher emission rates ({approximately} 10 ng/m{sup 2}hr) but were still comparable with natural background soils (- 0.3 to 13 ng/m{sup 2}hr). Air temperature, solar radiation, and relative humidity were important factors correlated with measured Hg fluxes. Field study results were not consistent with corresponding laboratory observations in that fluxes measured in the latter were higher and more variable. This is hypothesized to be partially an artifact of the flux measurement methods. 19 refs., 4 figs., 6 tabs.

Mei Xin; Mae S. Gustin; Kenneth Ladwig; Debra F. Pflughoeft-Hassett [University of Nevada, Reno, NV (United States). Department of Natural Resources and Environmental Science

2006-08-15

207

Advection fog formation and aerosols produced by combustion-originated air pollution  

NASA Technical Reports Server (NTRS)

The way in which pollutants produced by the photochemical reaction of NO(X) and SO(X) affect the quality of the human environment through such phenomena as the formation of advection fog is considered. These pollutants provide the major source of condensation nuclei for the formation of fog in highways, airports and seaports. Results based on the monodisperse, multicomponent aerosol model show that: (1) condensation nuclei can grow and form a dense fog without the air having attained supersaturation; (2) the mass concentration range for NO(X) is one-third that of SO(X); and (3) the greater the mass concentration, the particle concentration, and the radius of condensation nuclei, the denser the fog that is formed.

Hung, R. J.; Liaw, G. S.; Vaughan, O. H., Jr.

1980-01-01

208

Investigation Of Synergistic NOx Reduction From Cofiring And Air Staged Combustion Of Coal And Low Ash Dairy Biomass In A 30 Kilowatt Low NOx Furnace  

E-print Network

INVESTIGATION OF SYNERGISTIC NOX REDUCTION FROM COFIRING AND AIR STAGED COMBUSTION OF COAL AND LOW ASH DAIRY BIOMASS IN A 30 KILOWATT LOW NOX FURNACE A Dissertation by BENJAMIN DANIEL LAWRENCE Submitted to the Office of Graduate Studies....21 NOx Results from Cofiring PRB and LADB in a Conventional Furnace ............................................................................................... 41 2.22 NOx Results from Cofiring Coal and Litter Biomass in a Conventional...

Lawrence, Benjamin Daniel

2013-08-01

209

Method and apparatus for obtaining a control variable for the closed-loop control of the fuel-air ratio in the operating mixture of internal combustion engines  

Microsoft Academic Search

A method and apparatus is proposed for obtaining a control variable for the closed-loop control of the fuel-air ratio of the operating mixture of internal combustion engines, in which a threshold-current sensor of known structure is used. By means of varying the measurement voltage present at the threshold-current sensor by voltage amounts which correspond to a change in oxygen concentration

H. Dietz; E. Linder; H. Maurer; K. Muller; H. Reber; F. Rieger

1982-01-01

210

The effect of low-NO{sub x} combustion on residual carbon in fly ash and its adsorption capacity for air entrainment admixtures in concrete  

SciTech Connect

Fly ash from pulverized coal combustion contains residual carbon that can adsorb the air-entraining admixtures (AEAs) added to control the air entrainment in concrete. This is a problem that has increased by the implementation of low-NO{sub x} combustion technologies. In this work, pulverized fuel has been combusted in an entrained flow reactor to test the impact of changes in operating conditions and fuel type on the AEA adsorption of ash and NO{sub x} formation. Increased oxidizing conditions, obtained by improved fuel-air mixing or higher excess air, decreased the AEA requirements of the produced ash by up to a factor of 25. This was due to a lower carbon content in the ash and a lower specific AEA adsorptivity of the carbon. The latter was suggested to be caused by changes in the adsorption properties of the unburned char and a decreased formation of soot, which was found to have a large AEA adsorption capacity based on measurements on a carbon black. The NO{sub x} formation increased by up to three times with more oxidizing conditions and thus, there was a trade-off between the AEA requirements of the ash and NO{sub x} formation. The type of fuel had high impact on the AEA adsorption behavior of the ash. Ashes produced from a Columbian and a Polish coal showed similar AEA requirements, but the specific AEA adsorptivity of the carbon in the Columbian coal ash was up to six times higher. The AEA requirements of a South African coal ash was unaffected by the applied operating conditions and showed up to 12 times higher AEA adsorption compared to the two other coal ashes. This may be caused by larger particles formed by agglomeration of the primary coal particles in the feeding phase or during the combustion process, which gave rise to increased formation of soot. (author)

Pedersen, K.H.; Jensen, A.D.; Dam-Johansen, K. [Department of Chemical and Biochemical Engineering, Technical University of Denmark, Building 229, DK-2800 Kgs. Lyngby (Denmark)

2010-02-15

211

Plasma igniter for internal-combustion engines  

NASA Technical Reports Server (NTRS)

Hot ionized gas (plasma) ignites air/fuel mixture in internal combustion engines more effectively than spark. Electromagnetic forces propel plasma into combustion zone. Combustion rate is not limited by flame-front speed.

Breshears, R. R.; Fitzgerald, D. J.

1978-01-01

212

Method for combustion of gaseous fuels and flue gases  

Microsoft Academic Search

The invention discloses a method for combustion of gaseous fuels and flue gases in which the heat content of the combustion products is partially recycled to the combustion process by heat exchange with combustion air and\\/or gas, and air and gas are fed to a reaction chamber, where a surface combustion takes place separating air and gas regions, and the

1979-01-01

213

Thermochemical nonequilibrium and radiative interactions in supersonic hydrogen-air combustion  

NASA Technical Reports Server (NTRS)

The two-dimensional, elliptic Navier-Stokes equations are used to investigate supersonic flows with nonequilibrium chemistry and thermodynamics, coupled with radiation, for hydrogen-air systems. The chemistry source term in the species equation is treated implicitly to alleviate the stiffness associated with fast reactions. The explicit, unsplit MacCormack finite-difference scheme is used to advance the governing equations in time, until convergence is achieved. The specific problem considered is the premixed, expanding flow in a supersonic nozzle. The reacting flow consists of seven species, one of which is the inert N2 molecule. The thermal state of the gas is modeled with one translational-rotational temperature and five vibrational temperatures. The harmonic oscillator model is used in the formulation for vibrational relaxation. The tangent slab approximation is used in the radiative flux formulation. A pseudo-gray model is used to represent the absorption-emission characteristics of the participating species. Results obtained for specific conditions indicate the presence of nonequilibrium in the expansion region. This reduces the radiative interactions and can have a significant influence on the flowfield.

Chandrasekhar, R.; Tiwari, S. N.

1992-01-01

214

Air pollution from household solid fuel combustion in India: an overview of exposure and health related information to inform health research priorities  

PubMed Central

Environmental and occupational risk factors contribute to nearly 40% of the national burden of disease in India, with air pollution in the indoor and outdoor environment ranking amongst leading risk factors. It is now recognized that the health burden from air pollution exposures that primarily occur in the rural indoors, from pollutants released during the incomplete combustion of solid fuels in households, may rival or even exceed the burden attributable to urban outdoor exposures. Few environmental epidemiological efforts have been devoted to this setting, however. We provide an overview of important available information on exposures and health effects related to household solid fuel use in India, with a view to inform health research priorities for household air pollution and facilitate being able to address air pollution within an integrated rural–urban framework in the future. PMID:21987631

Balakrishnan, Kalpana; Ramaswamy, Padmavathi; Sambandam, Sankar; Thangavel, Gurusamy; Ghosh, Santu; Johnson, Priscilla; Mukhopadhyay, Krishnendu; Venugopal, Vidhya; Thanasekaraan, Vijayalakshmi

2011-01-01

215

Improved wound management by regulated negative pressure-assisted wound therapy and regulated, oxygen- enriched negative pressure-assisted wound therapy through basic science research and clinical assessment.  

PubMed

Regulated negative pressure-assisted wound therapy (RNPT) should be regarded as a state-of-the-art technology in wound treatment and the most important physical, nonpharmaceutical, platform technology developed and applied for wound healing in the last two decades. RNPT systems maintain the treated wound's environment as a semi-closed, semi-isolated system applying external physical stimulations to the wound, leading to biological and biochemical effects, with the potential to substantially influence wound-host interactions, and when properly applied may enhance wound healing. RNPT is a simple, safe, and affordable tool that can be utilized in a wide range of acute and chronic conditions, with reduced need for complicated surgical procedures, and antibiotic treatment. This technology has been shown to be effective and safe, saving limbs and lives on a global scale. Regulated, oxygen-enriched negative pressure-assisted wound therapy (RO-NPT) is an innovative technology, whereby supplemental oxygen is concurrently administered with RNPT for their synergistic effect on treatment and prophylaxis of anaerobic wound infection and promotion of wound healing. Understanding the basic science, modes of operation and the associated risks of these technologies through their fundamental clinical mechanisms is the main objective of this review. PMID:23162229

Topaz, Moris

2012-05-01

216

Research Opportunities for Cancer Associated with Indoor Air Pollution from Solid-Fuel Combustion  

PubMed Central

Background: Indoor air pollution (IAP) derived largely from the use of solid fuels for cooking and heating affects about 3 billion people worldwide, resulting in substantial adverse health outcomes, including cancer. Women and children from developing countries are the most exposed populations. A workshop was held in Arlington, Virginia, 9–11 May 2011, to better understand women’s and children’s potential health effects from IAP in developing countries. Workshop participants included international scientists, manufacturers, policy and regulatory officials, community leaders, and advocates who held extensive discussions to help identify future research needs. Objectives: Our objective was to identify research opportunities regarding IAP and cancer, including research questions that could be incorporated into studies of interventions to reduce IAP exposure. In this commentary, we describe the state of the science in understanding IAP and its associations with cancer and suggest research opportunities for improving our understanding of the issues. Discussion: Opportunities for research on IAP and cancer include studies of the effect of IAP on cancers other than lung cancer; studies of genetic factors that modify susceptibility; studies to determine whether the effects of IAP are mediated via germline, somatic, and/or epigenetic changes; and studies of the effects of IAP exposure via dermal and/or oral routes. Conclusions: IAP from indoor coal use increases the risk of lung cancer. Installing chimneys can reduce risk, and some genotypes, including GSTM1-null, can increase risk. Additional research is needed regarding the effects of IAP on other cancers and the effects of different types of solid fuels, oral and dermal routes of IAP exposure, genetic and epigenetic mechanisms, and genetic susceptibility. PMID:22846419

Ghazarian, Armen A.; DeMarini, David M.; Sapkota, Amir; Jack, Darby; Lan, Qing; Winn, Deborah M.; Birnbaum, Linda S.

2012-01-01

217

A new test method for the assessment of the arc tracking properties of wire insulation in air, oxygen enriched atmospheres and vacuum  

Microsoft Academic Search

Development of a new test method suitable for the assessment of the resistance of aerospace cables to arc tracking for different specific environmental and network conditions of spacecraft is given in view-graph format. The equipment can be easily adapted for tests at different realistic electrical network conditions incorporating circuit protection and the test system works equally well whatever the test

Dieter Koenig

1994-01-01

218

Air  

MedlinePLUS

... do to protect yourself from dirty air . Indoor air pollution and outdoor air pollution Air can be polluted indoors and it can ... this chart to see what things cause indoor air pollution and what things cause outdoor air pollution! Indoor ...

219

Influence of fuel moisture, charge size, feeding rate and air ventilation conditions on the emissions of PM, OC, EC, parent PAHs, and their derivatives from residential wood combustion.  

PubMed

Controlled combustion experiments were conducted to investigate the influence of fuel charge size, moisture, air ventilation and feeding rate on the emission factors (EFs) of carbonaceous particulate matter, parent polycyclic aromatic hydrocarbons (pPAHs) and their derivatives from residential wood combustion in a typical brick cooking stove. Measured EFs were found to be independent of fuel charge size, but increased with increasing fuel moisture. Pollution emissions from the normal burning under an adequate air supply condition were the lowest for most pollutants, while more pollutants were emitted when an oxygen deficient atmosphere was formed in the stove chamber during fast burning. The impacts of these factors on the size distribution of emitted particles was also studied. Modified combustion efficiency and the four investigated factors explained 68%, 72%, and 64% of total variations in EFs of PM, organic carbon, and oxygenated PAHs, respectively, but only 36%, 38% and 42% of the total variations in EFs of elemental carbon, pPAHs and nitro-PAHs, respectively. PMID:24520723

Shen, Guofeng; Xue, Miao; Wei, Siye; Chen, Yuanchen; Zhao, Qiuyue; Li, Bing; Wu, Haisuo; Tao, Shu

2013-09-01

220

The Influence of Fuel Moisture, Charge Size, Burning Rate and Air Ventilation Conditions on Emissions of PM, OC, EC, Parent PAHs, and Their Derivatives from Residential Wood Combustion  

PubMed Central

Controlled combustion experiments were conducted to investigate the influence of fuel charge size, moisture, air ventilation and burning rate on the emission factors (EFs) of carbonaceous particulate matter, parent polycyclic aromatic hydrocarbons (pPAHs) and their derivatives from residential wood combustion in a typical brick cooking stove. Measured EFs were found to be independent of fuel charge size, but increased with increasing fuel moisture. Pollution emissions from a normal burning under an adequate air supply condition were the lowest for most pollutants, while more pollutants were emitted when the oxygen deficient atmosphere was formed in stove chamber during fast burning. The impact of these 4 factors on particulate matter size distribution was also studied. Modified combustion efficiency and the four investigated factors explained 68, 72, and 64% of total variations in EFs of PM, organic carbon, and oxygenated PAHs, respectively, but only 36, 38 and 42% of the total variations in EFs of elemental carbon, pPAHs and nitro-PAHs, respectively. PMID:24520723

Shen, Guofeng; Xue, Miao; Wei, Siye; Chen, Yuanchen; Wang, Bin; Wang, Rong; Lv, Yan; Shen, Huizhong; Li, Wei; Zhang, Yanyan; Huang, Ye; Chen, Han; Wei, Wen; Zhao, Qiuyue; Li, Bin; Wu, Haisuo; TAO, Shu

2014-01-01

221

NO.sub.x reduction method  

DOEpatents

A method of reducing oxides of nitrogen (NO.sub.X) in the exhaust of an internal combustion engine includes producing oxygen enriched air and nitrogen enriched air by an oxygen enrichment device. The oxygen enriched air may be provided to the intake of the internal combustion engine for mixing with fuel. In order to reduce the amount of NO.sub.X in the exhaust of the internal combustion engine, the molecular nitrogen in the nitrogen enriched air produced by the oxygen enrichment device is subjected to a corona or arc discharge so as to create a plasma and as a result, atomic nitrogen. The resulting atomic nitrogen then is injected into the exhaust of the internal combustion engine causing the oxides of nitrogen in the exhaust to be reduced into nitrogen and oxygen. In one embodiment of the present invention, the oxygen enrichment device that produces both the oxygen and nitrogen enriched air can include a selectively permeable membrane.

Sekar, Ramanujam R. (Naperville, IL); Hoppie, Lyle O. (West Bloomfield, MI)

1996-01-01

222

EMISSIONS ASSESSMENT OF CONVENTIONAL STATIONARY COMBUSTION SYSTEMS: VOLUME V: INDUSTRIAL COMBUSTION SOURCES  

EPA Science Inventory

The report characterizes air emissions from industrial external combustion sources and is the last of a series of five reports characterizing emissions from conventional combustion sources. The emissions characterization of industrial combustion sources was based on a critical ex...

223

N-Decane-Air Droplet Combustion Experiments in the NASA-Lewis 5 Second Zero-Gravity Facility  

NASA Technical Reports Server (NTRS)

The burning of single fuel (n-decane) droplets in a microgravity environment (below 0.00001 of the earth's gravity, achieved in the NASA-Lewis 5-Second Zero-Gravity Facility) was studied, as part of the development of the Droplet Combustion Experiment for eventual operation aboard either the Shuttle middeck or Spacelab. Special attention is given to the combustion equipment used and its operations and performance. Temporal analysis of the local burning rates in these tests showed increasing rates of change in the local burning as droplet combustion progressed. Result point to the need of studying large droplets, with long droplet combustion lifetimes as well as low gas/droplet motion to understand reasons for this unsteadiness.

Haggard, John B.; Brace, Michael H.; Dryer, Frederick L.; Choi, Mun Y.; Williams, Forman A.

1990-01-01

224

Regulating low-NOx and high-burnout deep-air-staging combustion under real-furnace conditions in a 600 MWe down-fired supercritical boiler by strengthening the staged-air effect.  

PubMed

A 600 MW(e) down-fired pulverized-coal supercritical boiler, which was equipped with a deep-air-staging combustion system for reducing the particularly high NOx emissions, suffered from the well-accepted contradiction between low NOx emissions and high carbon in fly ash, in addition to excessively high gas temperatures in the hopper that jeopardized the boiler's safe operations. Previous results uncovered that under low-NOx conditions, strengthening the staged-air effect by decreasing the staged-air angle and simultaneously increasing the staged-air damper opening alleviated the aforementioned problems to some extent. To establish low-NOx and high-burnout circumstances and control the aforementioned hopper temperatures, a further staged-air retrofit with horizontally redirecting staged air through an enlarged staged-air slot area was performed to greatly strengthen the staged-air effect. Full-load industrial-size measurements were performed to confirm the availability of this retrofit. The present data were compared with those published results before the retrofit. High NOx emissions, low carbon in fly ah, and high hopper temperatures (i.e., levels of 1036 mg/m(3) at 6% O2, 3.72%, and about 1300 °C, respectively) appeared under the original conditions with the staged-air angle of 45° and without overfire air (OFA) application. Applying OFA and reducing the angle to 20° achieved an apparent NOx reduction and a moderate hopper temperature decrease while a sharp increase in carbon in fly ash (i.e., levels of 878 mg/m(3) at 6% O2, about 1200 °C, and 9.81%, respectively). Fortunately, the present staged-air retrofit was confirmed to be applicable in regulating low-NOx, high-burnout, and low hopper temperature circumstances (i.e., levels of 867 mg/m(3) at 6% O2, 5.40%, and about 1100 °C, respectively). PMID:25256210

Kuang, Min; Wang, Zhihua; Zhu, Yanqun; Ling, Zhongqian; Li, Zhengqi

2014-10-21

225

Membrane-based air composition control for light-duty diesel vehicles : a benefit and cost assessment.  

SciTech Connect

This report presents the methodologies and results of a study conducted by Argonne National Laboratory (Argonne) to assess the benefits and costs of several membrane-based technologies. The technologies evaluated will be used in automotive emissions-control and performance-enhancement systems incorporated into light-duty diesel vehicle engines. Such engines are among the technologies that are being considered to power vehicles developed under the government-industry Partnership for a New Generation of Vehicles (PNGV). Emissions of nitrogen oxides (NO{sub x}) from diesel engines have long been considered a barrier to use of diesels in urban areas. Recently, particulate matter (PM) emissions have also become an area of increased concern because of new regulations regarding emissions of particulate matter measuring 2.5 micrometers or less (PM2.5). Particulates are of special concern for diesel engines in the PNGV program; the program has a research goal of 0.01 gram per mile (g/mi) of particulate matter emissions under the Federal Test Procedure (FTP) cycle. This extremely low level (one-fourth the level of the Tier II standard) could threaten the viability of using diesel engines as stand-alone powerplants or in hybrid-electric vehicles. The techniques analyzed in this study can reduce NO{sub x} and particulate emissions and even increase the power density of the diesel engines used in light-duty diesel vehicles. For nearly a decade, Argonne has been evaluating membrane-based methods to control the composition of air used in combustion. Membranes are the only practical method of modifying air composition for on-board use. The applicability of the technique depends strongly on both the technical and economic feasibility of implementing it on a vehicle. Over the past 10 years, significant technical advances have been made in the development of air-separation membranes. Researchers have developed and commercialized novel membrane materials that can efficiently separate air at the concentrations required for vehicle applications and have developed compact membrane modules that can be incorporated into vehicle design. Previous analysis by Argonne and others has demonstrated the effectiveness of oxygen enrichment at reducing PM, smoke, hydrocarbon (HC), and carbon monoxide (CO) emissions while increasing engine power output. Under appropriate oxygen-enriched operating conditions, diesel engines have achieved a net increase of 10-20% in power density and a decrease of 30-60% in PM emissions. Nitrogen-enriched air can be used as an alternative to exhaust gas recirculation to control NO{sub x} emissions and can also be used to generate a monatomic nitrogen plasma for exhaust post-treatment to reduce emissions of NO{sub x}. Argonne has recently identified an operating regime that can simultaneously reduce NO{sub x} and PM while increasing power output when oxygen-enriched combustion air is used. This promising technique, which will be verified by additional experimental work at Argonne (using a range of engine sizes), will require the use of membranes similar to those analyzed in this study.

Poola, R.; Stork, K.

1998-11-09

226

Waste plastics as supplemental fuel in the blast furnace process: improving combustion efficiencies.  

PubMed

The possibility of using waste plastics as a source of secondary fuel in a blast furnace has been of recent interest. The success of this process, however, will be critically dependent upon the optimization of operating systems. For instance, the supply of waste plastics must be reliable as well as economically attractive compared with conventional secondary fuels such as heavy oil, natural gas and pulverized coal. In this work, we put special importance on the improvement of the combustibility of waste plastics as a way to enhance energy efficiency in a blast furnace. As experimental variables to approach this target, the effects of plastic particle size, blast temperature, and the level of oxygen enrichment were investigated using a custom-made blast model designed to simulate a real furnace. Lastly, the combustion efficiency of the mixture of waste plastics and pulverized coal was tested. The observations made from these experiments led us to the conclusion that with the increase of both blast temperature and the level of oxygen enrichment, and with a decrease in particle size, the combustibility of waste polyethylene could be improved at a given distance from the tuyere. Also it was found that the efficiency of coal combustion decreased with the addition of plastics; however, the combustion efficiency of mixture could be comparable at a longer distance from the tuyere. PMID:12220825

Kim, Dongsu; Shin, Sunghye; Sohn, Seungman; Choi, Jinshik; Ban, Bongchan

2002-10-14

227

Opportunities in pulse combustion  

SciTech Connect

In most pulse combustors, the combustion occurs near the closed end of a tube where inlet valves operate in phase with the pressure amplitude variations. Thus, within the combustion zone, both the temperature and the pressure oscillate around a mean value. However, the development of practical applications of pulse combustion has been hampered because effective design requires the right combination of the combustor's dimensions, valve characteristics, fuel/oxidizer combination, and flow pattern. Pulse combustion has several additional advantages for energy conversion efficiency, including high combustion and thermal efficiency, high combustion intensity, and high convective heat transfer rates. Also, pulse combustion can be self-aspirating, generating a pressure boost without using a blower. This allows the use of a compact heat exchanger that may include a condensing section and may obviate the need for a chimney. In the last decade, these features have revived interest in pulse combustion research and development, which has resulted in the development of a pulse combustion air heater by Lennox, and a pulse combustion hydronic unit by Hydrotherm, Inc. To appraise this potential for energy savings, a systematic study was conducted of the many past and present attempts to use pulse combustion for practical purposes. The authors recommended areas where pulse combustion technology could possibly be applied in the future and identified areas in which additional R and D would be necessary. Many of the results of the study project derived from a special workshop on pulse combustion. This document highlights the main points of the study report, with particular emphasis on pulse combustion application in chemical engineering.

Brenchley, D.L.; Bomelburg, H.J.

1985-10-01

228

Internal combustion engine control system  

Microsoft Academic Search

This patent describes an internal combustion engine control system comprising: A detector which measures the quantity of intake air and quantity of fuel supply as a control value reflecting the operational state of an internal combustion engine; An air-fuel ratio control which determines, based on the measured controlled variable, a base control value used for controlling the other controlled variable;

M. Kiyono; T. Abe; M. Takao

1989-01-01

229

System of wood combustion employing forced draft  

SciTech Connect

A system of wood combustion employing forced draft is disclosed and comprises a forced draft air and flue arrangement which is utilized with a typical wood heater or wood stove. The forced air and flue arrangement includes a blower, a plenum on which the blower is attached, a panel to which the plenum is attached having air inlets formed therethrough, the air inlets being internal to the plenum, and a flue arrangement attached to the other side of the panel. The flue arrangement includes ducts leading from the air inlets, the ducts having air nozzle slits formed on the other end thereof which are communicable with the internal portions of the wood heater or wood stove. Forced air from the blower enters the combustion chamber through the air nozzle slits. Immediately adjacent to the air nozzle slits and formed as a portion of the flue arrangement is an internal flue outlet for providing an exhaust exit for combustion gases, the flue outlet being communicable with an exhaust pipe. This forced draft air and flue arrangement provides for more complete combustion by combining secondary combustion of the excess air and unburned combustibles released during a previous primary combustion with the current primary combustion of the wood fuel thereby minimizing the amount of excess air and unburned combustibles and thereby improving the combustion efficiency of the wood stove. This is accomplished by forcing the combustion exhaust gases which are attempting to exit through the flue outlet to recirculate back into the combustion chamber. Directly adjacent locations of the air nozzle slits with the flue outlet causes this forced recirculation of the excess air and unburned combustibles generated during the primary combustion of the wood fuel.

Stark, I.

1981-12-08

230

Safety Design and Mock-Up Tests on the Combustion of Hydrogen-Air Mixture in the Vertical CNS Channel of the CARR-CNS  

SciTech Connect

A two-phase thermo-siphon loop is applied to the Cold Neutron Source (CNS) of China Advanced Research Reactor (CARR). The moderator is liquid hydrogen. The two-phase thermo-siphon consists of the crescent-shape moderator cell, the moderator transfer tube, and the condenser. The hydrogen is supplied from the buffer tank to the condenser. The most characteristic point is that the cold helium gas is introduced into the helium sub-cooling system covering the moderator cell and then flows up through the tube covering the moderator transfer tube into the condenser. The helium sub-cooling system also reduces the void fraction of the liquid hydrogen and takes a role of the helium barrier for preventing air from intruding into the hydrogen system. We call the two-phase thermo-siphon the hydrogen cold system. The main part of this system is installed in the CNS channel made of 6061 aluminum alloy (6061A) of 6 mm in thickness, 270 mm in outer diameter and about 6 m in height. For confirming the safety of the CNS, the combustion tests were carried out using the hydrogen-air mixture under the conditions in which air is introduced into the tube at 1 atmosphere, and then hydrogen gas is supplied from the gas cylinder up to the test pressures. And maximum test pressure is 0.140 MPa Gauge (G). This condition includes the design accident of the CNS. The peak pressure due to combustion is 1.09 MPa, and the design strength of the CNS channel is 3 MPa. The safety of the CNS was thus verified even if the design basis accident occurs. The pressure distribution, the stress, and the displacement of the tube were also measured. (authors)

Qingfeng Yu; Quanke Feng [Xi'an Jiaotong University, No.28, Xianning West Road, Xi'an, Shaanxi, 710049 (China)

2006-07-01

231

Combustion rate limits of hydrogen plus hydrocarbon fuel: air diffusion flames from an opposed jet burner technique  

Microsoft Academic Search

Combustion of Hâ\\/hydrocarbon (HC) fuel mixtures may be considered in certain volume-limited supersonic airbreathing propulsion applications. Effects of HC addition to Hâ were evaluated, using a recent argon-bathed, coaxial, tubular opposed jet burner (OJB) technique to measure the extinction limits of counterflow diffusion flames. The OJB flames were formed by a laminar jet of (Nâ and\\/or HC)-diluted Hâ mixture opposed

G. L. Pellett; R. Guerra; L. G. Wilson; R. N. Reeves; G. B. Northam

1987-01-01

232

Effect of heat recirculation on the self-sustained catalytic combustion of propane/air mixtures in a quartz reactor  

SciTech Connect

The self-sustained catalytic combustion of propane is experimentally studied in a two-pass, quartz heat-recirculation reactor (HRR) and compared to that in a no (heat) recirculation reactor (NRR). Structured monolithic reactors with Pt/{gamma}-Al{sub 2}O{sub 3}, LaMnO{sub 3}/{gamma}-Al{sub 2}O{sub 3}, and Pt doped perovskite catalysts have been compared in the HRR and NRR configurations. Heat recirculation enhances combustion stability, by widening the operating window of self-sustained operation, and changes the mode of stability loss from blowout to extinction. It is found that thermal shields (upstream and downstream of the monolith) play no role in the stability of a HRR but increase the stability of a NRR. The stability of a HRR follows this trend: Pt/{gamma}-Al{sub 2}O{sub 3} > doped perovskite > LaMnO{sub 3}/{gamma}-Al{sub 2}O{sub 3}. Finally, a higher cell density monolith enlarges the operating window of self-sustained combustion, and allows further increase of the power density of the process. (author)

Scarpa, A. [Dipartimento di Ingegneria Chimica, Universita degli Studi di Napoli ''Federico II'', P.le V. Tecchio 80, 80125 Naples (Italy); Department of Chemical Engineering, Center for Catalytic Science and Technology (CCST), and Center for Composite Materials (CCM), University of Delaware, 150 Academy Street, Newark, DE 19716 (United States); Pirone, R. [Istituto di Ricerche sulla Combustione-CNR, P.le V. Tecchio 80, 80125 Naples (Italy); Russo, G. [Dipartimento di Ingegneria Chimica, Universita degli Studi di Napoli ''Federico II'', P.le V. Tecchio 80, 80125 Naples (Italy); Vlachos, D.G. [Department of Chemical Engineering, Center for Catalytic Science and Technology (CCST), and Center for Composite Materials (CCM), University of Delaware, 150 Academy Street, Newark, DE 19716 (United States)

2009-05-15

233

EFFECTS OF CHANGING COALS ON THE EMISSIONS OF METAL HAZARDOUS AIR POLLUTANTS FROM THE COMBUSTION OF PULVERIZED COAL  

EPA Science Inventory

The report discusses tests conducted at EPA's Air Pollution Prevention and Control Division to evaluate the effects of changing coals on emissions of metal hazardous air pollutants from coal-fired boilers. Six coals were burned in a 29 kW (100,000 Btu/hr) down-fired combustor und...

234

Species and velocity visualization of unseeded heated air and combusting hydrogen jets using laser and flashlamp sources  

NASA Technical Reports Server (NTRS)

Three techniques for the visualization of species and/or velocity in unseeded H2/air flames and heated air jets are described and preliminary image data are presented. The techniques described are: (1) simultaneous ArF laser imaging of H2, O2, and Rayleigh cross-section weighted density in an H2, O2, and Rayleigh cross-section weighted density in an H2/air flame; (2) ultraviolet flashlamp imaging of O2, OH, and Rayleigh cross-section weighted density in an H2/air flame; and (3) Raman Excitation plus Laser Induced Electronic Fluorescence velocimetry in heater air flows, up to static temperatures of 700 K. Application of these techniques, individually or in combination, should provide useful insight into mixing and reacting flows containing H2, O2, N2 and reaction intermediates such as OH.

Diskin, Glenn S.; Lempert, Walter R.; Miles, Richard B.

1990-01-01

235

N-Decane Droplet Combustion in the NASA-Lewis 5 Second Zero-Gravity Facility - Results in Test Gas Environments Other than Air  

NASA Technical Reports Server (NTRS)

The burning rate of single droplets of n-decane in a microgravity environment of the NASA-Lewis 5 Second Zero-Gravity Facility was investigated as a function of time, together with the flame diameter/droplet diameter ratio, for a wide range of test environments other than normal air conditions, using an engineering model of the flight experiment. Oxygen mole fractions were varied from 18 to 50 percent, the total test chamber pressure was varied from 0.5 to 2 atmospheres, and the initial droplet diameter was varied from 0.98 to 2.41 mm. Measurements showed that the average burning rates for n-decane droplets exhibited the same qualitative trends as are found in two current models. Temporal analysis of the local burning rates showed variable rates of change in local burning as the droplet combustion progressed. The causes and implications of these findings are discussed.

Haggard, John B.; Borowski, Brian A.; Dryer, Frederick L.; Choi, Mun Y.; Williams, Forman A.

1991-01-01

236

Formation mechanisms of combustion chamber deposits  

E-print Network

Combustion chamber deposits are found in virtually all internal combustion engines after a few hundred hours of operation. Deposits form on cylinder, piston, and head surfaces that are in contact with fuel-air mixture ...

O'Brien, Christopher J. (Christopher John)

2001-01-01

237

Mock-up tests on the combustion of hydrogen air mixture in the vertical tube simulating the CNS channel of the CARR  

NASA Astrophysics Data System (ADS)

A two-phase thermo-siphon loop for removing nuclear heating and maintaining the stable liquid level in the moderator cell was adopted for the cold neutron source (CNS) of the China advanced research reactor (CARR). The moderator is liquid hydrogen. The two-phase thermo-siphon loop consists of the crescent-shape moderator cell, the moderator transfer tube, and the condenser. The hydrogen is supplied from the buffer tank to the condenser. The main feature of the loop is that the moderator cell is covered by the helium sub-cooling system. The cold helium gas from the helium refrigerator is firstly introduced into the helium sub-cooling system and then flows up through the tube covering the moderator transfer tube into the condenser. The main part of this system is installed in the CNS vertical channel made of aluminum alloy 6061 T6 (Al-6061-T6) of 6 mm in thickness, 270 mm in outer diameter and about 6 m in height. For confirming the safety of the CNS channel, the combustion tests using a tube compatible with the CNS channel were carried out using the hydrogen-air mixture under which air is introduced into the tube at 1 atmosphere, and then hydrogen gas is supplied from the gas cylinder up to the test pressures. And maximum test pressure is 0.14 MPa G. This condition is involved with the maximum design basis accident of the CARR-CNS. The peak pressure due to combustion was 1.09 MPa, and the design pressure of the CNS channel is 3 MPa. The safety of the CNS was thus verified even if the maximum design basis accident occurs. The pressure and stress distributions along the axial direction and the displacement of the tube were also measured.

Yu, Qingfeng; Feng, Quanke; Kawai, Takeshi; Xu, Jian

2007-01-01

238

INHALABLE PARTICLES AND PULMONARY HOST DEFENSE: 'IN VIVO' AND 'IN VITRO' EFFECTS OF AMBIENT AIR AND COMBUSTION PARTICLES  

EPA Science Inventory

The ability of particulate air pollutants (and possible constituents) to alter pulmonary host defenses was examined using an in vitro alveolar macrophage cytotoxicity assay and an in vivo bacterial infectivity screening test which employed intratracheal injection of the particles...

239

Combustion products generating and metering device  

NASA Technical Reports Server (NTRS)

An apparatus for generating combustion products at a predetermined fixed rate, mixing the combustion products with air to achieve a given concentration, and distributing the resultant mixture to an area or device to be tested is described. The apparatus is comprised of blowers, a holder for the combustion product generating materials (which burn at a predictable and controlled rate), a mixing plenum chamber, and a means for distributing the air combustion product mixture.

Wiberg, R. E.; Klisch, J. A. (inventors)

1971-01-01

240

Internal combustion engine with rotary combustion chamber  

Microsoft Academic Search

This patent describes an internal combustion engine comprising: a block having at least one cylindrical wall surrounding a piston chamber, piston means located in the piston chamber means operable to reciprocate the piston means in the chamber, head means mounted on the block covering the chamber. The head means has an air and fuel intake passage, and exhaust gas passage,

C. N. Hansen; P. C. Cross

1986-01-01

241

Internal combustion engine with rotary combustion chamber  

Microsoft Academic Search

This patent describes an internal combustion engine comprising: a block having at least one cylindrical wall surrounding a piston chamber, piston means located in the piston chamber, means operable to reciprocate the piston means in the chamber, head means mounted on the block covering the chamber. The head means having an air and fuel intake passage, an exhaust gas passage,

C. N. Hansen; P. C. Cross

1988-01-01

242

Contribution of wood combustion to indoor air pollution as measured by mutagenicity in Salmonella and polycyclic aromatic hydrocarbon concentration.  

PubMed

Samples of airborne particles have been collected in the same room when the room was heated by electricity and when heating was done by woodburning. These samples were compared with respect to mutagenic activity and concentration of polycyclic aromatic hydrocarbons (PAH). The effects of the various heating conditions were examined in the presence and absence of tobacco smoking. Whereas wood heating in an "airtight" stove was found to cause only minor changes in the concentration of PAH and no measurable increase of mutagenic activity of the indoor air, both these parameters increased considerably when wood was burned in an open fireplace, yielding PAH concentrations comparable to those of ambient urban air. Relatively high concentrations of moderately polar polycyclic aromatic hydrocarbon derivatives were also found in the indoor air when wood was burned in an open fireplace. Woodburning in the closed stove did, however, result in increased concentrations of mutagenic compounds and PAH on particles sampled in the vicinity of the house. The effects of wood burning in an open fireplace on the mutagenic activity of indoor air could still be considered moderate when compared to those resulting from tobacco smoking in the room. The extracts of particles collected when moderate smoking occurred were several times more mutagenic than samples from urban air collected close to streets with heavy traffic when measured in the Salmonella assay with strain TA98 with metabolic activation. PMID:6368216

Alfheim, I; Ramdahl, T

1984-01-01

243

Leaching behavior and possible resource recovery from air pollution control residues of fluidized bed combustion of municipal solid waste  

SciTech Connect

Ash residues are generated at several points during combustion of municipal solid waste (MSW), i.e., in cyclones, electrostatic precipitators and fabric filters. Such residues are of a complex physical and chemical nature and are often enriched in soluble salts and heavy metals such as Pb, Cd and Zn. Fluidized bed combustion (FBC) of MSW is a relatively new technique and very little information is available about the leaching behavior of its residues. In this study, the total elemental composition, mineralogy and leaching behavior of cyclone and bag-house filter ashes from a bubbling fluidized bed (BFB) boiler fired with municipal solid waste have been investigated. In addition, the possibilities of recovery heavy metals from these ashes were studied. The long-term leaching behavior of the ash constituents was evaluated using a two-step batch leaching test known as the CEN-test, whereas short and medium term leaching behavior was evaluated using a Column test. The extraction of elements from cyclone and filter ashes with various acidic solutions was also investigated. The leaching behavior of acid washed ashes was evaluated using the CEN test. The cyclone ash was mainly composed of aluminosilicate minerals, whereas the filter ash consisted of chlorides and hydroxides of alkali and alkaline earth metals. The concentration of heavy metals such as Zn, Cu, Cd and Pb was higher in the filter ash than in the cyclone ash. The leached amounts of sulfates and Pb from the cyclone ash decreased with leaching test contact time, indicating the formation of secondary mineral phases. Large amounts of chlorides, sulfates, Ca, Cu and Pb were leached from the filter ash. Acid extraction removed large amounts ({gt}50%) of Zn, Pb and Cu from the filter ash and approximately 56% of the total amount of Zn present in the cyclone ash. An efficient removal of heavy metal species from these types of ashes can probably be achieved by application of a recycling or multi-step process.

Abbas, Z.; Andersson, B.A.; Steenari, B.M.

1999-07-01

244

Modelling inhalation exposure to combustion-related air pollutants in residential buildings: Application to health impact assessment  

Microsoft Academic Search

Buildings in developed countries are becoming increasingly airtight as a response to stricter energy efficiency requirements. At the same time, changes are occurring to the ways in which household energy is supplied, distributed and used. These changes are having important impacts on exposure to indoor air pollutants in residential buildings and present new challenges for professionals interested in assessing the

James Milner; Sotiris Vardoulakis; Zaid Chalabi; Paul Wilkinson

2011-01-01

245

Summary of Simplified Two Time Step Method for Calculating Combustion Rates and Nitrogen Oxide Emissions for Hydrogen/Air and Hydrogen/Oxygen  

NASA Technical Reports Server (NTRS)

A simplified single rate expression for hydrogen combustion and nitrogen oxide production was developed. Detailed kinetics are predicted for the chemical kinetic times using the complete chemical mechanism over the entire operating space. These times are then correlated to the reactor conditions using an exponential fit. Simple first order reaction expressions are then used to find the conversion in the reactor. The method uses a two time step kinetic scheme. The first time averaged step is used at the initial times with smaller water concentrations. This gives the average chemical kinetic time as a function of initial overall fuel air ratio, temperature, and pressure. The second instantaneous step is used at higher water concentrations (greater than l x 10(exp -20)) moles per cc) in the mixture which gives the chemical kinetic time as a function of the instantaneous fuel and water mole concentrations, pressure and temperature (T(sub 4)). The simple correlations are then compared to the turbulent mixing times to determine the limiting properties of the reaction. The NASA Glenn GLSENS kinetics code calculates the reaction rates and rate constants for each species in a kinetic scheme for finite kinetic rates. These reaction rates are used to calculate the necessary chemical kinetic times. This time is regressed over the complete initial conditions using the Excel regression routine. Chemical kinetic time equations for H2 and NOx are obtained for H2/Air fuel and for H2/O2. A similar correlation is also developed using data from NASA's Chemical Equilibrium Applications (CEA) code to determine the equilibrium temperature (T(sub 4)) as a function of overall fuel/air ratio, pressure and initial temperature (T(sub 3)). High values of the regression coefficient R squared are obtained.

Marek, C. John; Molnar, Melissa

2005-01-01

246

Simplified Two-Time Step Method for Calculating Combustion Rates and Nitrogen Oxide Emissions for Hydrogen/Air and Hydorgen/Oxygen  

NASA Technical Reports Server (NTRS)

A simplified single rate expression for hydrogen combustion and nitrogen oxide production was developed. Detailed kinetics are predicted for the chemical kinetic times using the complete chemical mechanism over the entire operating space. These times are then correlated to the reactor conditions using an exponential fit. Simple first order reaction expressions are then used to find the conversion in the reactor. The method uses a two-time step kinetic scheme. The first time averaged step is used at the initial times with smaller water concentrations. This gives the average chemical kinetic time as a function of initial overall fuel air ratio, temperature, and pressure. The second instantaneous step is used at higher water concentrations (> 1 x 10(exp -20) moles/cc) in the mixture which gives the chemical kinetic time as a function of the instantaneous fuel and water mole concentrations, pressure and temperature (T4). The simple correlations are then compared to the turbulent mixing times to determine the limiting properties of the reaction. The NASA Glenn GLSENS kinetics code calculates the reaction rates and rate constants for each species in a kinetic scheme for finite kinetic rates. These reaction rates are used to calculate the necessary chemical kinetic times. This time is regressed over the complete initial conditions using the Excel regression routine. Chemical kinetic time equations for H2 and NOx are obtained for H2/air fuel and for the H2/O2. A similar correlation is also developed using data from NASA s Chemical Equilibrium Applications (CEA) code to determine the equilibrium temperature (T4) as a function of overall fuel/air ratio, pressure and initial temperature (T3). High values of the regression coefficient R2 are obtained.

Molnar, Melissa; Marek, C. John

2005-01-01

247

Flame propagation, autoignition and combustion in alcohol-petroleum-air mixtures and other alternative fuels. Final report, August 1, 1977December 31, 1978  

Microsoft Academic Search

The main goal of this program is to determine the combustion characteristics of the future alternative fuels in gasoline, diesel engines so that future combustion engines may be designed for best energy conversion and minimum emissions. The approach consists of studying the process of combustion in actual engines to obtain data needed to either design new engines or modify and

Henein

1979-01-01

248

Effects of Water Vapor and CO2 Addition on Combustion Characteristics for Lean Hydrocarbon-Air Mixtures under Normal and Microgravity Conditions  

Microsoft Academic Search

Experiments on combustion of extremely lean mixtures in the vicinity of flammability limits have acquired importance from the viewpoint of development of new kinds of combustion systems having low fuel consumption and low emissions. Furthermore, the determination of combustion characteristics for vapor addition under normal gravity and microgravity is very important for control of safety engineering in the space. In

Y. SHIBATA; T. KAWAKAMI; A. TEODORCZYK

249

EMISSIONS ASSESSMENT OF CONVENTIONAL STATIONARY COMBUSTION SYSTEMS: VOLUME IV. COMMERCIAL/INSTITUTIONAL COMBUSTION SOURCES  

EPA Science Inventory

The report characterizes air emissions from commercial/institutional external combustion sources and reciprocating engines and is the fourth of a series of five project reports characterizing emissions from conventional combustion sources. This characterization was based on a cri...

250

REFERENCE GUIDELINE FOR INDUSTRIAL BOILER MANUFACTURERS TO CONTROL POLLUTION WITH COMBUSTION MODIFICATION  

EPA Science Inventory

The report describes combustion modification methods that are available to boiler manufacturers for controlling air pollutant emissions from industrial size fossil-fuel-fired steam boilers. The methods discussed include reduction of excess air, staged combustion, air register adj...

251

Ignition apparatus for internal combustion engine  

Microsoft Academic Search

An ignition apparatus for an internal combustion engine comprises an intake path supplying a mixture of air and fuel into the combustion chamber of the engine, a particle supplying unit having an ejection port opening into the combustion chamber for supplying minute particles of a material which is not the fuel and has a high light absorption factor, and a

S. Mukainakano; T. Goto; T. Hattori; T. Mizuno; M. Nishida

1984-01-01

252

Secondary combustion device for woodburning stove  

SciTech Connect

This patent describes in a wood burning stove including an exhaust flue opening, a combustion chamber for primary combustion having an access door, a support for wood to be burned and a primary air inlet means for supplying air to support primary combustion of the wood to produce flue gases containing combustible particulate material, plenum means for directing the flue gases in a direction from the combustion chamber to the flue opening in a preselected path, and secondary combustion means for burning the particulate material in the flue gases before flue gases through the exhaust flue opening. The improvement comprising: the combustion chamber having a flue gas exit opening extending laterally across the top of the combustion chamber and communicating the combustion chamber with the plenum means, an elongated manifold extending laterally across and above the combustion chamber substantially coextensively with the flue gas exit opening, a number of air opening spaced longitudinally along the manifold and facing opposite the direction of the flue gases closely adjacent the flue gas exit opening, and an air inlet means for supplying ambient, secondary combustion air to the manifold for counterflow thereof from the openings into the path of the flue gases in a plurality of distinct jets.

Craver, R.D.

1989-08-08

253

Spherical combustion clouds in explosions  

NASA Astrophysics Data System (ADS)

This study explores the properties of spherical combustion clouds in explosions. Two cases are investigated: (1) detonation of a TNT charge and combustion of its detonation products with air, and (2) shock dispersion of aluminum powder and its combustion with air. The evolution of the blast wave and ensuing combustion cloud dynamics are studied via numerical simulations with our adaptive mesh refinement combustion code. The code solves the multi-phase conservation laws for a dilute heterogeneous continuum as formulated by Nigmatulin. Single-phase combustion (e.g., TNT with air) is modeled in the fast-chemistry limit. Two-phase combustion (e.g., Al powder with air) uses an induction time model based on Arrhenius fits to Boiko's shock tube data, along with an ignition temperature criterion based on fits to Gurevich's data, and an ignition probability model that accounts for multi-particle effects on cloud ignition. Equations of state are based on polynomial fits to thermodynamic calculations with the Cheetah code, assuming frozen reactants and equilibrium products. Adaptive mesh refinement is used to resolve thin reaction zones and capture the energy-bearing scales of turbulence on the computational mesh (ILES approach). Taking advantage of the symmetry of the problem, azimuthal averaging was used to extract the mean and rms fluctuations from the numerical solution, including: thermodynamic profiles, kinematic profiles, and reaction-zone profiles across the combustion cloud. Fuel consumption was limited to ˜ 60-70 %, due to the limited amount of air a spherical combustion cloud can entrain before the turbulent velocity field decays away. Turbulent kinetic energy spectra of the solution were found to have both rotational and dilatational components, due to compressibility effects. The dilatational component was typically about 1 % of the rotational component; both seemed to preserve their spectra as they decayed. Kinetic energy of the blast wave decayed due to the pressure field. Turbulent kinetic energy of the combustion cloud decayed due to enstrophy overline{? 2} and dilatation overline{? 2}.

Kuhl, A. L.; Bell, J. B.; Beckner, V. E.; Balakrishnan, K.; Aspden, A. J.

2013-05-01

254

Demonstration of Air-Power-Assist Engine Technology for Clean Combustion and Direct Energy Recovery in Heavy Duty Application  

SciTech Connect

The first phase of the project consists of four months of applied research, starting from September 1, 2005 and was completed by December 31, 2005. During this time, the project team heavily relied on highly detailed numerical modeling techniques to evaluate the feasibility of the APA technology. Specifically, (i) A GT-Power{sup TM}engine simulation model was constructed to predict engine efficiency at various operating conditions. Efficiency was defined based on the second-law thermodynamic availability. (ii) The engine efficiency map generated by the engine simulation was then fed into a simplified vehicle model, which was constructed in the Matlab/Simulink environment, to predict fuel consumption of a refuse truck on a simple collection cycle. (iii) Design and analysis work supporting the concept of retrofitting an existing Sturman Industries Hydraulic Valve Actuation (HVA) system with the modifications that are required to run the HVA system with Air Power Assist functionality. A Matlab/Simulink model was used to calculate the dynamic response of the HVA system. Computer aided design (CAD) was done in Solidworks for mechanical design and hydraulic layout. At the end of Phase I, 11% fuel economy improvement was predicted. During Phase II, the engine simulation group completed the engine mapping work. The air handling group made substantial progress in identifying suppliers and conducting 3D modelling design. Sturman Industries completed design modification of the HVA system, which was reviewed and accepted by Volvo Powertrain. In Phase II, the possibility of 15% fuel economy improvement was shown with new EGR cooler design by reducing EGR cooler outlet temperature with APA engine technology from Air Handling Group. In addition, Vehicle Simulation with APA technology estimated 4 -21% fuel economy improvement over a wide range of driving cycles. During Phase III, the engine experimental setup was initiated at VPTNA, Hagerstown, MD. Air Handling system and HVA system were delivered to VPTNA and then assembly of APA engine was completed by June 2007. Functional testing of APA engine was performed and AC and AM modes testing were completed by October 2007. After completing testing, data analysis and post processing were performed. Especially, the models were instrumental in identifying some of the key issues with the experimental HVA system. Based upon the available engine test results during AC and AM modes, the projected fuel economy improvement over the NY composite cycle is 14.7%. This is close to but slightly lower than the originally estimated 18% from ADVISOR simulation. The APA project group demonstrated the concept of APA technology by using simulation and experimental testing. However, there are still exists of technical challenges to meet the original expectation of APA technology. The enabling technology of this concept, i.e. a fully flexible valve actuation system that can handle high back pressure from the exhaust manifold is identified as one of the major technical challenges for realizing the APA concept.

Hyungsuk Kang; Chun Tai

2010-05-01

255

Compressed air energy storage system  

DOEpatents

An internal combustion reciprocating engine is operable as a compressor during slack demand periods utilizing excess power from a power grid to charge air into an air storage reservoir and as an expander during peak demand periods to feed power into the power grid utilizing air obtained from the air storage reservoir together with combustible fuel. Preferably the internal combustion reciprocating engine is operated at high pressure and a low pressure turbine and compressor are also employed for air compression and power generation.

Ahrens, Frederick W. (Naperville, IL); Kartsounes, George T. (Naperville, IL)

1981-01-01

256

The contributions of emissions and spatial microenvironments to exposure to indoor air pollution from biomass combustion in Kenya.  

PubMed Central

Acute and chronic respiratory diseases, which are causally linked to exposure to indoor air pollution in developing countries, are the leading cause of global morbidity and mortality. Efforts to develop effective intervention strategies and detailed quantification of the exposure-response relationship for indoor particulate matter require accurate estimates of exposure. We used continuous monitoring of indoor air pollution and individual time-activity budget data to construct detailed profiles of exposure for 345 individuals in 55 households in rural Kenya. Data for analysis were from two hundred ten 14-hour days of continuous real-time monitoring of concentrations of particulate matter [less than/equal to] 10 microm in aerodynamic diameter and the location and activities of household members. These data were supplemented by data on the spatial dispersion of pollution and from interviews. Young and adult women had not only the highest absolute exposure to particulate matter (2, 795 and 4,898 microg/m(3) average daily exposure concentrations, respectively) but also the largest exposure relative to that of males in the same age group (2.5 and 4.8 times, respectively). Exposure during brief high-intensity emission episodes accounts for 31-61% of the total exposure of household members who take part in cooking and 0-11% for those who do not. Simple models that neglect the spatial distribution of pollution within the home, intense emission episodes, and activity patterns underestimate exposure by 3-71% for different demographic subgroups, resulting in inaccurate and biased estimations. Health and intervention impact studies should therefore consider in detail the critical role of exposure patterns, including the short periods of intense emission, to avoid spurious assessments of risks and benefits. PMID:11017887

Ezzati, M; Saleh, H; Kammen, D M

2000-01-01

257

Internal combustion engine  

Microsoft Academic Search

An internal combustion engine operating on a two-stroke cycle and including a piston 1 reciprocable in a cylinder 2 to drive a crank shaft and also to inhale and compress a volume of air is characterized by a second piston 15 working in a separate cylinder 13 co-axial with and opposed to the first cylinder 2, the piston 15 being

1982-01-01

258

Rotary internal combustion engine  

Microsoft Academic Search

This patent describes a rotary internal combustion engine operating on fuel and air, comprising: a housing having a pair of communicating parallel axis rotor chambers; a pair of parallel axis rotors, one in each rotor chamber of the housing, the rotors each having on its outer periphery circumferentially spaced axial teeth with intervening circumferentially spaced axial passages. The rotors are

Kollen

1987-01-01

259

Combustion noise  

NASA Technical Reports Server (NTRS)

A review of the subject of combustion generated noise is presented. Combustion noise is an important noise source in industrial furnaces and process heaters, turbopropulsion and gas turbine systems, flaring operations, Diesel engines, and rocket engines. The state-of-the-art in combustion noise importance, understanding, prediction and scaling is presented for these systems. The fundamentals and available theories of combustion noise are given. Controversies in the field are discussed and recommendations for future research are made.

Strahle, W. C.

1977-01-01

260

Internal combustion engine using premixed combustion of stratified charges  

DOEpatents

During a combustion cycle, a first stoichiometrically lean fuel charge is injected well prior to top dead center, preferably during the intake stroke. This first fuel charge is substantially mixed with the combustion chamber air during subsequent motion of the piston towards top dead center. A subsequent fuel charge is then injected prior to top dead center to create a stratified, locally richer mixture (but still leaner than stoichiometric) within the combustion chamber. The locally rich region within the combustion chamber has sufficient fuel density to autoignite, and its self-ignition serves to activate ignition for the lean mixture existing within the remainder of the combustion chamber. Because the mixture within the combustion chamber is overall premixed and relatively lean, NO.sub.x and soot production are significantly diminished.

Marriott, Craig D. (Rochester Hills, MI); Reitz, Rolf D. (Madison, WI

2003-12-30

261

The mechanism of two-dimensional pocket formation in lean premixed methane-air flames with implications to turbulent combustion  

SciTech Connect

The mechanism of unburnt pocket formation in an unsteady two-dimensional premixed lean methane-air flame is investigated using direct numerical simulations. Theoretical results for nonlinear diffusion equations combined with analytical examples are used to interpret some of the results. Flame structure and propagation show three distinct stages of pocket formation: (1) flame channel closing involving head-on quenching of flames, (2) cusp recovery, and (3) pocket burnout. The flame channel closing and subsequent pocket burnout are mutual annihilation events that feature curvature, diffusion normal to the flame front, unsteady strain rate effects, and singularities in flame propagation and stretch rate. The results show that during channel closing and pocket burnout thermo-diffusive and chemical interactions result in the acceleration of the flames prior to annihilation; the time scales associated with the final stage of mutual annihilation and the initial stage of cusp recovery are significantly smaller than diffusive and convective time scales. Peak radical concentrations resulting from flame channel closing and pocket burnout exceed peak laminar values by as much as 25%. After the merging of the fuel consumption layers, radical production and flame structure shifts more towards an H{sub 2}/CO/O{sub 2} system at the expense of hydrocarbon reactions. Species thermodiffusive interaction times are shorter than the unstrained one-dimensional counterpart due to unsteady strain and convection. Curvature effects on the flame propagation are prominent during pocket burnout and cusp recovery. The recovery stage shows strong dependence on diffusion of radicals left from the channel closing stage. This diffusion is amplified by the strong curvature of the flame cusp.

Chen, J.H.; Echekki, T. [Sandia National Labs., Livermore, CA (United States). Combustion Research Facility] [Sandia National Labs., Livermore, CA (United States). Combustion Research Facility; Kollmann, W. [Univ. of California, Davis, CA (United States). Mechanical and Aerospace Engineering Dept.] [Univ. of California, Davis, CA (United States). Mechanical and Aerospace Engineering Dept.

1999-01-01

262

Internal combustion engine with rotary exhaust control  

Microsoft Academic Search

This patent describes an internal combustion engine with a sequential operating cycle. It comprises a cylinder; a piston reciprocal in the cylinder; at least one intake port for admitting air into the cylinder in combination with at least one exhaust\\/intake port for exhausting combustion gases from the cylinder and admitting additional air into the cylinder; and, a rotary commutator valve

M. A. Paul; A. Paul

1992-01-01

263

Combustion 2000  

SciTech Connect

This report is a presentation of work carried out on Phase II of the HIPPS program under DOE contract DE-AC22-95PC95144 from June 1995 to March 2001. The objective of this report is to emphasize the results and achievements of the program and not to archive every detail of the past six years of effort. These details are already available in the twenty-two quarterly reports previously submitted to DOE and in the final report from Phase I. The report is divided into three major foci, indicative of the three operational groupings of the program as it evolved, was restructured, or overtaken by events. In each of these areas, the results exceeded DOE goals and expectations. HIPPS Systems and Cycles (including thermodynamic cycles, power cycle alternatives, baseline plant costs and new opportunities) HITAF Components and Designs (including design of heat exchangers, materials, ash management and combustor design) Testing Program for Radiative and Convective Air Heaters (including the design and construction of the test furnace and the results of the tests) There are several topics that were part of the original program but whose importance was diminished when the contract was significantly modified. The elimination of the subsystem testing and the Phase III demonstration lessened the relevance of subtasks related to these efforts. For example, the cross flow mixing study, the CFD modeling of the convective air heater and the power island analysis are important to a commercial plant design but not to the R&D product contained in this report. These topics are of course, discussed in the quarterly reports under this contract. The DOE goal for the High Performance Power Plant System ( HIPPS ) is high thermodynamic efficiency and significantly reduced emissions. Specifically, the goal is a 300 MWe plant with > 47% (HHV) overall efficiency and {le} 0.1 NSPS emissions. This plant must fire at least 65% coal with the balance being made up by a premium fuel such as natural gas. To achieve these objectives requires a change from complete reliance of coal-fired systems on steam turbines (Rankine cycles) and moving forward to a combined cycle utilizing gas turbines (Brayton cycles) which offer the possibility of significantly greater efficiency. This is because gas turbine cycles operate at temperatures well beyond current steam cycles, allowing the working fluid (air) temperature to more closely approach that of the major energy source, the combustion of coal. In fact, a good figure of merit for a HIPPS design is just how much of the enthalpy from coal combustion is used by the gas turbine. The efficiency of a power cycle varies directly with the temperature of the working fluid and for contemporary gas turbines the optimal turbine inlet temperature is in the range of 2300-2500 F (1260-1371 C). These temperatures are beyond the working range of currently available alloys and are also in the range of the ash fusion temperature of most coals. These two sets of physical properties combine to produce the major engineering challenges for a HIPPS design. The UTRC team developed a design hierarchy to impose more rigor in our approach. Once the size of the plant had been determined by the choice of gas turbine and the matching steam turbine, the design process of the High Temperature Advanced Furnace (HITAF) moved ineluctably to a down-fired, slagging configuration. This design was based on two air heaters: one a high temperature slagging Radiative Air Heater (RAH) and a lower temperature, dry ash Convective Air Heater (CAH). The specific details of the air heaters are arrived at by an iterative sequence in the following order:-Starting from the overall Cycle requirements which set the limits for the combustion and heat transfer analysis-The available enthalpy determined the range of materials, ceramics or alloys, which could tolerate the temperatures-Structural Analysis of the designs proved to be the major limitation-Finally the commercialization issues of fabrication and reliability, availability and maintenance. The program that has s

A. Levasseur; S. Goodstine; J. Ruby; M. Nawaz; C. Senior; F. Robson; S. Lehman; W. Blecher; W. Fugard; A. Rao; A. Sarofim; P. Smith; D. Pershing; E. Eddings; M. Cremer; J. Hurley; G. Weber; M. Jones; M. Collings; D. Hajicek; A. Henderson; P. Klevan; D. Seery; B. Knight; R. Lessard; J. Sangiovanni; A. Dennis; C. Bird; W. Sutton; N. Bornstein; F. Cogswell; C. Randino; S. Gale; Mike Heap

2001-06-30

264

Controlling Indoor Air Pollution.  

ERIC Educational Resources Information Center

Discusses the health risks posed by indoor air pollutants, such as airborne combustion products, toxic chemicals, and radioactivity. Questions as to how indoor air might be regulated. Calls for new approaches to environmental protection. (TW)

Nero, Anthony V, Jr.

1988-01-01

265

Utilization of coal mine ventilation exhaust as combustion air in gas-fired turbines for electric and/or mechanical power generation. Semi-annual topical report, June 1995--August 1995  

SciTech Connect

Methane emitted during underground coal mining operations is a hazard that is dealt with by diluting the methane with fresh air and exhausting the contaminated air to the atmosphere. Unfortunately this waste stream may contain more than 60% of the methane resource from the coal, and in the atmosphere the methane acts as a greenhouse gas with an effect about 24.5 times greater than CO{sub 2}. Though the waste stream is too dilute for normal recovery processes, it can be used as combustion air for a turbine-generator, thereby reducing the turbine fuel requirements while reducing emissions. Preliminary analysis indicates that such a system, built using standard equipment, is economically and environmentally attractive, and has potential for worldwide application.

NONE

1995-12-01

266

Catalytic combustion with steam injection  

NASA Technical Reports Server (NTRS)

The effects of steam injection on (1) catalytic combustion performance, and (2) the tendency of residual fuel to burn in the premixing duct upstream of the catalytic reactor were determined. A petroleum residual, no. 2 diesel, and a blend of middle and heavy distillate coal derived fuels were tested. Fuel and steam were injected together into the preheated airflow entering a 12 cm diameter catalytic combustion test section. The inlet air velocity and pressure were constant at 10 m/s and 600 kPa, respectively. Steam flow rates were varied from 24 percent to 52 percent of the air flow rate. The resulting steam air mixture temperatures varied from 630 to 740 K. Combustion temperatures were in the range of 1200 to 1400 K. The steam had little effect on combustion efficiency or emissions. It was concluded that the steam acts as a diluent which has no adverse effect on catalytic combustion performance for no. 2 diesel and coal derived liquid fuels. Tests with the residual fuel showed that upstream burning could be eliminated with steam injection rates greater than 30 percent of the air flow rate, but inlet mixture temperatures were too low to permit stable catalytic combustion of this fuel.

Anderson, D. N.; Tacina, R. R.

1982-01-01

267

Fluidized-bed combustion  

SciTech Connect

This report describes the activities of the Morgantown Energy Technology Center's research and development program in fluidized-bed combustion from October 1, 1987, to September 30, 1989. The Department of Energy program involves atmospheric and pressurized systems. Demonstrations of industrial-scale atmospheric systems are being completed, and smaller boilers are being explored. These systems include vortex, multi-solid, spouted, dual-sided, air-cooled, pulsed, and waste-fired fluidized-beds. Combustion of low-rank coal, components, and erosion are being studied. In pressurized combustion, first-generation, combined-cycle power plants are being tested, and second-generation, advanced-cycle systems are being designed and cost evaluated. Research in coal devolatilization, metal wastage, tube corrosion, and fluidization also supports this area. 52 refs., 24 figs., 3 tabs.

Botros, P E

1990-04-01

268

Secondary combustion device for woodburning stove  

SciTech Connect

This patent describes a wood burning stove including an exhaust flue opening, a combustion chamber for primary combustion having an access door, a support for wood to be burnt and a primary air inlet means for supplying air to support primary combustion of the wood to produce flue gases containing combustible particulate material. A conduit means for directing the flue gases is included from the combustion chamber to the flue opening in a preselected path. Also included is a secondary combustion means for burning particulate material in flue gases before flue gases pass through the exhaust flue opening. The improvement comprises: secondary combustion means including an elongated manifold extending laterally across and above the combustion chamber at a preselected position on the preselected path; a number of air openings spaced longitudinally along the manifold and facing the path of the flue gases and an air inlet means for supplying ambient; secondary combustion air to the manifold for flow from openings into the path of the flue gases in distinct jets; and a laterally elongated passageway above the manifold with upper and lower portions and defined at its upper portion by a sheet metal wall, and a layer of extremely low heat conducting insulation in the passageway. On the sheet metal wall the layer of insulation prevents appreciable conduction of heat from the passageway into the sheet metal wall and flue gases flow through the passageway and from passageway in a generally wide thin flow pattern.

Craver, R.D.

1987-06-16

269

Microgravity Smoldering Combustion Takes Flight  

NASA Technical Reports Server (NTRS)

The Microgravity Smoldering Combustion (MSC) experiment lifted off aboard the Space Shuttle Endeavour in September 1995 on the STS-69 mission. This experiment is part of series of studies focused on the smolder characteristics of porous, combustible materials in a microgravity environment. Smoldering is a nonflaming form of combustion that takes place in the interior of combustible materials. Common examples of smoldering are nonflaming embers, charcoal briquettes, and cigarettes. The objective of the study is to provide a better understanding of the controlling mechanisms of smoldering, both in microgravity and Earth gravity. As with other forms of combustion, gravity affects the availability of air and the transport of heat, and therefore, the rate of combustion. Results of the microgravity experiments will be compared with identical experiments carried out in Earth's gravity. They also will be used to verify present theories of smoldering combustion and will provide new insights into the process of smoldering combustion, enhancing our fundamental understanding of this frequently encountered combustion process and guiding improvement in fire safety practices.

1996-01-01

270

Improved Combustion Efficiencies - Control Systems for Process Heaters and Boilers  

E-print Network

are discussed and the need for modern control is stressed. Modern control systems offered by leading manufacturers are discussed in detail. Modern combustion control systems are designed to provide safe and proper combustion, desired air/fuel ratio, reduced...

Varma, A. C.; Prengle, H. W.

1979-01-01

271

COMBUSTION SOURCES OF UNREGULATED GAS PHASE NITROGENEOUS SPECIES  

E-print Network

use the of lean bacterial Estimates of production of N othat N0 2 production peaked at the lean air/fuel ratio oflean combustion systems. laboratory combustion systems have also revealed the production

Matthews, Ronald D.

2013-01-01

272

Some Factors Affecting Combustion in an Internal-Combustion Engine  

NASA Technical Reports Server (NTRS)

An investigation of the combustion of gasoline, safety, and diesel fuels was made in the NACA combustion apparatus under conditions of temperature that permitted ignition by spark with direct fuel injection, in spite of the compression ratio of 12.7 employed. The influence of such variables as injection advance angle, jacket temperature, engine speed, and spark position was studied. The most pronounced effect was that an increase in the injection advance angle (beyond a certain minimum value) caused a decrease in the extent and rate of combustion. In almost all cases combustion improved with increased temperature. The results show that at low air temperatures the rates of combustion vary with the volatility of the fuel, but that at high temperatures this relationship does not exist and the rates depend to a greater extent on the chemical nature of the fuel.

Rothrock, A M; Cohn, Mildred

1936-01-01

273

The effects of spark ignition parameters on the lean burn limit of natural gas combustion in an internal combustion engine  

E-print Network

A full factorial experiment was conducted to determine the effects of internal combustion engine ignition parameters on the air-fuel ratio (A/F) lean limit of combustion with compressed natural gas (CNG). Spark electrical characteristics (voltage...

Chlubiski, Vincent Daniel

1997-01-01

274

Flameless Combustion for Gas Turbines  

NASA Astrophysics Data System (ADS)

An experimental study of a novel flameless combustor for gas turbine engines is presented. Flameless combustion is characterized by distributed flame and even temperature distribution for high preheat air temperature and large amount of recirculating low oxygen exhaust gases. Extremely low emissions of NOx, CO, and UHC are reported. Measurements of the flame chemiluminescence, CO and NOx emissions, acoustic pressure, temperature and velocity fields as a function of the preheat temperature, inlet air mass flow rate, exhaust nozzle contraction ratio, and combustor chamber diameter are described. The data indicate that larger pressure drop promotes flameless combustion and low NOx emissions at the same flame temperature. High preheated temperature and flow rates also help in forming stable combustion and therefore are favorable for flameless combustion.

Gutmark, Ephraim; Li, Guoqiang; Overman, Nick; Cornwell, Michael; Stankovic, Dragan; Fuchs, Laszlo; Milosavljevic, Vladimir

2006-11-01

275

High velocity combustion furnace and burner  

SciTech Connect

A new high-velocity combustion system for heat-treating or forging furnaces improves upon prior designs in that it needs only a small combustion chamber and that several nozzles can be housed in a common air manifold. The combustion air is sufficiently pressurized to create a high flue-gas velocity that causes a backpressure within the combustion chamber, thus reducing the volume of space required in the chamber, bringing the refractory closer to the work piece, shortening the heat-treating time, and increasing the thermal load on the work pieces.

McElroy, J.G.

1982-01-05

276

High efficiency RCCI combustion  

NASA Astrophysics Data System (ADS)

An experimental investigation of the pragmatic limits of Reactivity Controlled Compression Ignition (RCCI) engine efficiency was performed. The study utilized engine experiments combined with zero-dimensional modeling. Initially, simulations were used to suggest conditions of high engine efficiency with RCCI. Preliminary simulations suggested that high efficiency could be obtained by using a very dilute charge with a high compression ratio. Moreover, the preliminary simulations further suggested that with simultaneous 50% reductions in heat transfer and incomplete combustion, 60% gross thermal efficiency may be achievable with RCCI. Following the initial simulations, experiments to investigate the combustion process, fuel effects, and methods to reduce heat transfer and incomplete combustion reduction were conducted. The results demonstrated that the engine cycle and combustion process are linked, and if high efficiency is to be had, then the combustion event must be tailored to the initial cycle conditions. It was found that reductions to engine heat transfer are a key enabler to increasing engine efficiency. In addition, it was found that the piston oil jet gallery cooling in RCCI may be unnecessary, as it had a negative impact on efficiency. Without piston oil gallery cooling, it was found that RCCI was nearly adiabatic, achieving 95% of the theoretical maximum cycle efficiency (air standard Otto cycle efficiency).

Splitter, Derek A.

277

Comment/Rebuttal Comments on "Electrorheology Leads to Efficient Combustion" by  

E-print Network

of combustion in general and internal combustion (IC) engine combustion technology in particular. Given, how does improved atomization increase combustion efficiency in gasoline engines? In a diesel engine into the air. In both modern gasoline and diesel engines, built within the last 10-20 years, combustion

Gülder, �mer L.

278

Combustion-gas recirculation system  

DOEpatents

A combustion-gas recirculation system has a mixing chamber with a mixing-chamber inlet and a mixing-chamber outlet. The combustion-gas recirculation system may further include a duct connected to the mixing-chamber inlet. Additionally, the combustion-gas recirculation system may include an open inlet channel with a solid outer wall. The open inlet channel may extend into the mixing chamber such that an end of the open inlet channel is disposed between the mixing-chamber inlet and the mixing-chamber outlet. Furthermore, air within the open inlet channel may be at a pressure near or below atmospheric pressure.

Baldwin, Darryl Dean (Lacon, IL)

2007-10-09

279

Difference Between IR Radiation Spectra of Ethanol in Free Diffusion Combustion Regime and Regime Influenced by an Air Flow in Modeling of a Fire Tornado  

NASA Astrophysics Data System (ADS)

Results of experimental investigations of liquid fuel combustion in the regime of a twisted jet (model of a fire tornado) are presented. Flame radiation spectra were registered. In the chosen spectral range of registration (2.2-4.8 ?m), six spectral intervals were clearly traced in which the main portion of radiated energy was concentrated. Using the ratio of the sums of spectral intensities in the vicinities of the 6th and 3rd maxima, we successfully distinguished the regimes of modeled fire tornado and free diffusion fuel combustion.

Sherstobitov, M. V.; Tsvyk, R. Sh.

2013-06-01

280

The investigation of exhaust powered, automotive air cycle air conditioning  

E-print Network

-Vane Air-Cycle Air-Conditioning and Refrigeration System, " SAE Paper No. 720079, 1972. 7. Edwards, T. C. , "The Rovac Automotive Air Conditioning System, " SAE Paper No. 75043, 1975 ' 8. Boyce, M. P. , "The Utilization of Internal Combustion Engine... Exhaust, for Air Conditioning, " SAE Paper No. 719162, 1971. 9. Christensen, A. J. , "Utilization of Internal Combustion Engine Exhaust for Air Conditioning, Supercharging, and Pollution Control, " Masters Thesis, Texas A8R University, December 1970...

Holley, James Andrew

1978-01-01

281

Survey of Hydrogen Combustion Properties  

NASA Technical Reports Server (NTRS)

This literature digest of hydrogen-air combustion fundamentals presents data on flame temperature, burning velocity, quenching distance, flammability limits, ignition energy, flame stability, detonation, spontaneous ignition, and explosion limits. The data are assessed, recommended values are given, and relations among various combustion properties are discussed. New material presented includes: theoretical treatment of variation in spontaneous ignition lag with temperature, pressure, and composition, based on reaction kinetics of hydrogen-air composition range for 0.01 to 100 atmospheres and initial temperatures of 0 degrees to 1400 degrees k.

Drell, Isadore L; Belles, Frank E

1958-01-01

282

Jet plume injection and combustion system for internal combustion engines  

SciTech Connect

This invention is comprised of an improved combustion system for an internal combustion engine is disclosed wherein a rich air/fuel mixture is furnished at high pressure to one or more jet plume generator cavities adjacent to a cylinder and then injected through one or more orifices from the cavities into the head space of the cylinder to form one or more turbulent jet plumes in the head space of the cylinder prior to ignition of the rich air/fuel mixture in the cavity of the jet plume generator. The portion of the rich air/fuel mixture remaining in the cavity of the generator is then ignited to provide a secondary jet, comprising incomplete combustion products which are injected into the cylinder to initiate combustion in the already formed turbulent jet plume. Formation of the turbulent jet plume in the head space of the cylinder prior to ignition has been found to yield a higher maximum combustion pressure in the cylinder, as well as shortening the time period to attain such a maximum pressure.

Oppenheim, A.K.; Maxson, J.A.; Hensinger, D.M.

1992-12-31

283

Jet plume injection and combustion system for internal combustion engines  

DOEpatents

An improved combustion system for an internal combustion engine is disclosed wherein a rich air/fuel mixture is furnished at high pressure to one or more jet plume generator cavities adjacent to a cylinder and then injected through one or more orifices from the cavities into the head space of the cylinder to form one or more turbulent jet plumes in the head space of the cylinder prior to ignition of the rich air/fuel mixture in the cavity of the jet plume generator. The portion of the rich air/fuel mixture remaining in the cavity of the generator is then ignited to provide a secondary jet, comprising incomplete combustion products which are injected into the cylinder to initiate combustion in the already formed turbulent jet plume. Formation of the turbulent jet plume in the head space of the cylinder prior to ignition has been found to yield a higher maximum combustion pressure in the cylinder, as well as shortening the time period to attain such a maximum pressure. 24 figures.

Oppenheim, A.K.; Maxson, J.A.; Hensinger, D.M.

1993-12-21

284

Jet plume injection and combustion system for internal combustion engines  

DOEpatents

An improved combustion system for an internal combustion engine is disclosed wherein a rich air/fuel mixture is furnished at high pressure to one or more jet plume generator cavities adjacent to a cylinder and then injected through one or more orifices from the cavities into the head space of the cylinder to form one or more turbulent jet plumes in the head space of the cylinder prior to ignition of the rich air/fuel mixture in the cavity of the jet plume generator. The portion of the rich air/fuel mixture remaining in the cavity of the generator is then ignited to provide a secondary jet, comprising incomplete combustion products which are injected into the cylinder to initiate combustion in the already formed turbulent jet plume. Formation of the turbulent jet plume in the head space of the cylinder prior to ignition has been found to yield a higher maximum combustion pressure in the cylinder, as well as shortening the time period to attain such a maximum pressure.

Oppenheim, Antoni K. (Kensington, CA); Maxson, James A. (Berkeley, CA); Hensinger, David M. (Albany, CA)

1993-01-01

285

Method and system for controlled combustion engines  

DOEpatents

A system for controlling combustion in internal combustion engines of both the Diesel or Otto type, which relies on establishing fluid dynamic conditions and structures wherein fuel and air are entrained, mixed and caused to be ignited in the interior of a multiplicity of eddies, and where these structures are caused to sequentially fill the headspace of the cylinders.

Oppenheim, A. K. (Berkeley, CA)

1990-01-01

286

Head for high performance internal combustion engine  

Microsoft Academic Search

This patent describes a cast head for high performance internal combustion engine of the type using an atomized mixture of air and liquid fuel, the head including a flat mounting surface and having, for each of several in-line circular piston areas, (a) a wedge type combustion chamber extending from a head mounting surface and defined by a flat quenching surface

R. W. Jr. Smith; M. E. Smith

1987-01-01

287

Combustion liner for a gas turbine engine  

Microsoft Academic Search

This patent describes, for a gas turbine power plant, a combustor having panels generally circular in shape and extending axially arranged end to end to define an annular combustion chamber. Each of the panels have an inner surface subjected to combustion gases and an outer surface subjected to power plant cooler air. It also has means on the downstream end

1986-01-01

288

Turbulent Combustion in SDF Explosions  

SciTech Connect

A heterogeneous continuum model is proposed to describe the dispersion and combustion of an aluminum particle cloud in an explosion. It combines the gas-dynamic conservation laws for the gas phase with a continuum model for the dispersed phase, as formulated by Nigmatulin. Inter-phase mass, momentum and energy exchange are prescribed by phenomenological models. It incorporates a combustion model based on the mass conservation laws for fuel, air and products; source/sink terms are treated in the fast-chemistry limit appropriate for such gasdynamic fields, along with a model for mass transfer from the particle phase to the gas. The model takes into account both the afterburning of the detonation products of the C-4 booster with air, and the combustion of the Al particles with air. The model equations were integrated by high-order Godunov schemes for both the gas and particle phases. Numerical simulations of the explosion fields from 1.5-g Shock-Dispersed-Fuel (SDF) charge in a 6.6 liter calorimeter were used to validate the combustion model. Then the model was applied to 10-kg Al-SDF explosions in a an unconfined height-of-burst explosion. Computed pressure histories are compared with measured waveforms. Differences are caused by physical-chemical kinetic effects of particle combustion which induce ignition delays in the initial reactive blast wave and quenching of reactions at late times. Current simulations give initial insights into such modeling issues.

Kuhl, A L; Bell, J B; Beckner, V E

2009-11-12

289

Combustion modeling in waste tanks  

SciTech Connect

This paper has two objectives. The first one is to repeat previous simulations of release and combustion of flammable gases in tank SY-101 at the Hanford reservation with the recently developed code GASFLOW-II. The GASFLOW-II results are compared with the results obtained with the HMS/TRAC code and show good agreement, especially for non-combustion cases. For combustion GASFLOW-II predicts a steeper pressure rise than HMS/TRAC. The second objective is to describe a so-called induction parameter model which was developed and implemented into GASFLOW-II and reassess previous calculations of Bureau of Mines experiments for hydrogen-air combustion. The pressure time history improves compared with the one-step model, and the time rate of pressure change is much closer to the experimental data.

Mueller, C.; Unal, C. [Los Alamos National Lab., NM (United States); Travis, J.R. [Los Alamos National Lab., NM (United States)]|[Forschungszentrum Karlsruhe (Germany). Inst. fuer Reaktorsicherheit

1997-08-01

290

Combustion Studies of Sawdust in a Bubbling Fluidized Bed  

Microsoft Academic Search

Biomass fuels are difficult to handle due to high moisture and fines content. In the present work, the effect of secondary air injection on combustion efficiency of sawdust in the fluidized bed combustor has been discussed. An enlarged disengagement section is provided to improve combustion of fines. The maximum possible combustion efficiency with saw dust is 99.2 % and is

K. V. N. Srinivasa Rao

2007-01-01

291

2002 Spring Technical Meeting Central States Section / The Combustion Institute  

E-print Network

Motors Research & Development Center Local Fuel-Air Ratio Measurements in Internal Combustion Engines Research Laboratory A Multi-dimensional Combustion Model for Gasoline Direct-Injection Engine Design 10 Emissions from Small Utility Engines 12:00 PM Lunch & Business Meeting SESSION A.2: Multiphase Combustion

Tennessee, University of

292

Method of controlling a free piston external combustion engine  

Microsoft Academic Search

A method is described for controlling the operation of an external combustion engine wherein the engine comprises: a compressor for compressing ambient air for supply to a combustion member including a free piston travelling between two end closures of a sleeve in which the piston slides reciprocatingly thus defining two combustion chambers between each end closure and the corresponding end

1987-01-01

293

Bubble Combustion  

NASA Technical Reports Server (NTRS)

A method of energy production that is capable of low pollutant emissions is fundamental to one of the four pillars of NASA s Aeronautics Blueprint: Revolutionary Vehicles. Bubble combustion, a new engine technology currently being developed at Glenn Research Center promises to provide low emissions combustion in support of NASA s vision under the Emissions Element because it generates power, while minimizing the production of carbon dioxide (CO2) and nitrous oxides (NOx), both known to be Greenhouse gases. and allows the use of alternative fuels such as corn oil, low-grade fuels, and even used motor oil. Bubble combustion is analogous to the inverse of spray combustion: the difference between bubble and spray combustion is that spray combustion is spraying a liquid in to a gas to form droplets, whereas bubble combustion involves injecting a gas into a liquid to form gaseous bubbles. In bubble combustion, the process for the ignition of the bubbles takes place on a time scale of less than a nanosecond and begins with acoustic waves perturbing each bubble. This perturbation causes the local pressure to drop below the vapor pressure of the liquid thus producing cavitation in which the bubble diameter grows, and upon reversal of the oscillating pressure field, the bubble then collapses rapidly with the aid of the high surface tension forces acting on the wall of the bubble. The rapid and violent collapse causes the temperatures inside the bubbles to soar as a result of adiabatic heating. As the temperatures rise, the gaseous contents of the bubble ignite with the bubble itself serving as its own combustion chamber. After ignition, this is the time in the bubble s life cycle where power is generated, and CO2, and NOx among other species, are produced. However, the pollutants CO2 and NOx are absorbed into the surrounding liquid. The importance of bubble combustion is that it generates power using a simple and compact device. We conducted a parametric study using CAVCHEM, a computational model developed at Glenn, that simulates the cavitational collapse of a single bubble in a liquid (water) and the subsequent combustion of the gaseous contents inside the bubble. The model solves the time-dependent, compressible Navier-Stokes equations in one-dimension with finite-rate chemical kinetics using the CHEMKIN package. Specifically, parameters such as frequency, pressure, bubble radius, and the equivalence ratio were varied while examining their effect on the maximum temperature, radius, and chemical species. These studies indicate that the radius of the bubble is perhaps the most critical parameter governing bubble combustion dynamics and its efficiency. Based on the results of the parametric studies, we plan on conducting experiments to study the effect of ultrasonic perturbations on the bubble generation process with respect to the bubble radius and size distribution.

Corrigan, Jackie

2004-01-01

294

Theoretical nitric oxide production incidental to autoignition and combustion of several fuels homogeneously dispersed in air under some typical hypersonic flight conditions  

NASA Technical Reports Server (NTRS)

A reaction package of 100 chemical reactions and attendant reaction rate constants defined for the autoignition and combustion of four carbonaceous fuels, CH4, CH3OH, C2H6, and C2H5OH. Definition of the package was made primarily by means of comparison between trial calculations and experimental data for the autoignition of CH4. Autoignition and combustion of each of these four fuels was calculated under three sets of conditions realistic for hypersonic flight applications, for comparison to hydrogen fuel, particularly with respect to formation of nitric oxide. Results show that, for all of the fuels including hydrogen, if NO production is a significant problem, compromise must be made between approaching equilibrium heat release and approaching equilibrium NO concentration.

Bahn, G. S.

1974-01-01

295

Furnace combustion zone temperature control method  

SciTech Connect

This patent describes a method for controlling temperature in a combustion zone in a furnace, independent of flue gas oxygen content. It comprises: supplying combustion air to the furnace for combustion of a fuel therein; providing a plurality of low volume gas flow entry ports to the combustion zone in the furnace with carrier gas continuously flowing through the ports into the combustion zone; selecting a set point value for the combustion zone temperature which, upon the temperature exceeding the set point value, commences generation of a fine water mist external the combustion zone by mist generating means within the carrier gas, the mist flowing into the combustion zone with the carrier gas and reducing temperature within the combustion zone by vaporization therein; and adding a proportionately greater amount of water mist to the carrier gas as the temperature of the combustion zone deviates above the set point value, the amount of water mist added limited by the capacity of the mist generating means, and ceasing the water mist generation upon the combustion zone temperature falling to or below the set point value.

McIntyre, G.C.; Lacombe, R.J.; Forbess, R.G.

1991-05-28

296

Catalyzing the Combustion of Coal  

NASA Technical Reports Server (NTRS)

Reaction rate of coal in air can be increased by contacting or coating coal with compound such as calcium acetate. The enhanced reaction rate generates more heat, reducing furnace size. Increase in combustion rate is about 26 percent, and internal pollutants in powerplant are reduced.

Humphrey, M. F.; Dokko, W.

1982-01-01

297

Internal combustion engine intake passage  

Microsoft Academic Search

This patent describes an air intake device for an internal combustion engine comprising: a cylinder head having an intake port; an intake manifold having an intake passage; and a spacer formed with an intake bore and interposed between the cylinder head and the intake manifold in such a manner that the intake port and the intake passage are communicated with

Y. Yamamoto; H. Yuzawa; T. N. Nishihara

1988-01-01

298

INDUCED SECONDARY COMBUSTION IN WOODSTOVES  

EPA Science Inventory

The paper provides information useful for woodstove designers concerned with reducing emissions. A dual-chamber woodstove was modified to induce secondary combustion by utilizing an ignition source and forced flow of secondary air. The ignition source was an electric glow plug in...

299

Gas turbine alternative fuels combustion characteristics  

NASA Astrophysics Data System (ADS)

An experimental investigation was conducted to obtain combustion performance and exhaust pollutant concentrations for specific synthetic hydrocarbon fuels. Baseline comparison fuels used were gasoline and diesel fuel number two. Testing was done over a range of fuel to air mass ratios, total mass flow rates, and input combustion air temperatures in a flame-tube-type gas turbine combustor. Test results were obtained in terms of released heat and combustion gas emission values. The results were comparable to those obtained with the base fuels with variations being obtained with changing operating conditions. The release of carbon particles during the tests was minimal.

Rollbuhler, R. James

1989-02-01

300

Simultaneous measurements of OH(A) and OH(X) radicals in microwave plasma jet-assisted combustion of methane/air mixtures around the lean-burn limit using optical emission spectroscopy and cavity ringdown spectroscopy  

NASA Astrophysics Data System (ADS)

We report a new plasma-assisted combustion system, in which a continuous atmospheric argon microwave plasma jet is employed to enhance combustion of methane/air mixtures in different fuel equivalence ratios (?) ranging from 0.35 to 1.5. The combustor has three distinct reaction zones along the jet axis (the combustion flame direction): the pure plasma zone, the hybrid plasma-flame zone and the combustion flame zone. Each of the three zones is clearly defined by its emission spectral fingerprints. The plasma zone was featured by strong emissions from OH and NH electronic bands and atomic lines of Ar, H? and H?. In the hybrid zone where the plasma jet met fuel mixtures, emission spectra were dominated by OH, NH and CN transitions and by weak or no atomic transitions. In the combustion flame zone, only weak OH emissions were observed. Simulations of optical emission spectroscopy (OES) yielded gas kinetic temperatures to be 1175 ± 50 K, 1450 ± 50 K and 1865 ± 50 K in each of the three zones, respectively. The plasma-enhancement effect was investigated by comparing the lean-burn limits of the combustion with and without plasma. At the same fuel mixture flow rate of 1.0 standard litre per minute and plasma power of 100 W, the lean-burn limit in terms of the fuel equivalence ratio ? was extended from 0.72 without assistance of the plasma to 0.35 with assistance of the plasma. In addition to OES that was employed to characterize the excited state species including OH(A) in the three different zones, pulsed cavity ringdown spectroscopy was utilized to measure absolute number densities of the ground state OH(X) using the OH A-X (0-0) R2 (1) line in different locations in the flame zone at ? = 0.51, 0.87, 1.10 and 1.45. For rich and lean combustions, significantly different OH(X) number densities and density profiles in the flame zone were observed. At ? = 0.51, the OH(X, V? = 0, J? = 0.5) number density increased from 2.29 × 1015 molecule cm-3 at the combustor nozzle to the maximum, 3.13 × 1015 molecule cm-3 at 2 mm downstream, and to the lowest detectable level of 0.12 × 1015 molecule cm-3 in the far downstream where optical emissions were too weak to be detected. Results from the simultaneous measurements of the electronically excited state OH(A) and the ground state OH(X) allow us to discuss the roles of OH(A) and OH(X) in the plasma-assisted ignition and the flame stabilization, respectively.

Wang, Chuji; Wu, Wei

2013-11-01

301

Turbulent combustion  

SciTech Connect

Turbulent combustion is the dominant process in heat and power generating systems. Its most significant aspect is to enhance the burning rate and volumetric power density. Turbulent mixing, however, also influences the chemical rates and has a direct effect on the formation of pollutants, flame ignition and extinction. Therefore, research and development of modern combustion systems for power generation, waste incineration and material synthesis must rely on a fundamental understanding of the physical effect of turbulence on combustion to develop theoretical models that can be used as design tools. The overall objective of this program is to investigate, primarily experimentally, the interaction and coupling between turbulence and combustion. These processes are complex and are characterized by scalar and velocity fluctuations with time and length scales spanning several orders of magnitude. They are also influenced by the so-called {open_quotes}field{close_quotes} effects associated with the characteristics of the flow and burner geometries. The authors` approach is to gain a fundamental understanding by investigating idealized laboratory flames. Laboratory flames are amenable to detailed interrogation by laser diagnostics and their flow geometries are chosen to simplify numerical modeling and simulations and to facilitate comparison between experiments and theory.

Talbot, L.; Cheng, R.K. [Lawrence Berkeley Laboratory, CA (United States)

1993-12-01

302

Engine air intake valve  

Microsoft Academic Search

This paper discusses, in combination with an internal combustion engine, a system for regulating engine speed by regulating the air flow across a throttle valve in an air intake passage. It comprises an engine air intake valve and means of sensing an operating variable representative of engine speed and sending an electrical signal representative of the engine speed to the

1990-01-01

303

Rotary internal combustion engine  

SciTech Connect

This patent describes a rotary internal combustion engine operating on fuel and air, comprising: a housing having a pair of communicating parallel axis rotor chambers; a pair of parallel axis rotors, one in each rotor chamber of the housing, the rotors each having on its outer periphery circumferentially spaced axial teeth with intervening circumferentially spaced axial passages. The rotors are positioned with the teeth and passages of one rotor engaging, respectively, the passages and teeth of the other rotor, and each of the rotors further having an internal chamber surrounding axial generally cylindrical oblique helicoid walls forming a mixer means; mean for introducing a mixture of the fuel and air into the mixer chambers of the rotors whereby rotating of the rotors correspondingly rotates and mixer means to homogenize the mixture to produce a fuel/air mist; means for transferring the mist from the mixer chambers to a predetermined injection point in the rotor chambers of the housing such that the mist is disposed in selected passages of the rotors as the selected passages rotate past the predetermined injection point; means for igniting the mist at a predetermined ignition point in the rotor chambers of the housing. The predetermined ignition point is proximate a combustion chamber formed by interengagement of the teeth of the rotors immediately adjacent the selected passages. Exhaust resulting from ignition of the mist urges expansion of the combustion chamber and causes rotation of the rotors; and means for extracting the exhaust as the selected passages rotate past a predetermined exhaust point in the rotor chambers of the housing. The predetermined exhaust point is located in the rotor chambers such that the selected passages of the rotors rotate past the predetermined exhaust point before rotating past the predetermined injection point.

Kollen, R.H.

1987-01-06

304

Reciprocating internal-combustion engine of low-temperature catalytic-combustion type  

Microsoft Academic Search

This patent describes a reciprocating combustion engine powered by an air-fuel mixture and which includes a reciprocal piston and a cylinder defining a combustion chamber. The piston has a head which includes a top surface, the combustion chamber has inner walls with a piston-sliding region and areas separate from the piston-sliding region, along which areas a relatively thin low-temperature quench

Hagino

1986-01-01

305

Got Dirty Air?  

NSDL National Science Digital Library

Students are introduced to the concepts of air pollution and technologies that have been developed by engineers to reduce air pollution. Students develop an understanding of visible air pollutants with an incomplete combustion demonstration, a "smog in a jar" demonstration, construction of simple particulate matter collectors and by exploring engineering roles related to air pollution. Next, students develop awareness and understanding of the daily air quality and trends in air quality using the Air Quality Index (AQI) listed in the newspaper. Finally, students build and observe a variety of simple models in order to develop an understanding of how engineers use these technologies to clean up and prevent air pollution.

Integrated Teaching And Learning Program

306

EMISSION REDUCTION ON TWO INDUSTRIAL BOILERS WITH MAJOR COMBUSTION MODIFICATIONS  

EPA Science Inventory

The report gives results of a study of the effects on pollutant emissions of extensive combustion modifications on two industrial boilers. Staged combustion, variable excess air, and variable air preheat were evaluated while firing natural gas or No. 6 fuel oil in a watertube boi...

307

MONITORING STRATEGIES FOR FLUIDIZED BED COMBUSTION COAL PLANTS  

EPA Science Inventory

Air and water monitoring strategies for commercial-size Fluidized Bed Combustion (FBC) coal plants are presented. This is one of five reports developing air and water monitoring strategies for advanced coal combustion (FBC), coal conversion (coal gasification and liquefaction), a...

308

APPLICATION OF COMBUSTION MODIFICATIONS TO INDUSTRIAL COMBUSTION EQUIPMENT (DATA SUPPLEMENT B)  

EPA Science Inventory

The supplement provides raw data from a study of the effects of combustion modifications on air pollutant emissions from a variety of industrial combustion equipment. Tested were 22 units, including refinery process heaters; clay and cement kilns; steel and aluminum furnaces; boi...

309

APPLICATION OF COMBUSTION MODIFICATIONS TO INDUSTRIAL COMBUSTION EQUIPMENT (DATA SUPPLEMENT A)  

EPA Science Inventory

The supplement provides raw data from a study of the effects of combustion modifications on air pollutant emissions from a variety of industrial combustion equipment. Tested were 22 units, including refinery process heaters; clay and cement kilns; steel and aluminum furnaces; boi...

310

Comparison of Different Global Reaction Mechanisms for MILD Combustion of Natural Gas  

Microsoft Academic Search

Emissions of nitrogen oxides from fossil fuel combustion are a major environmental problem because they have been shown to contribute to the formation of acid rain and photochemical smog. MILD (Moderate and Intensive Low oxygen Dilution) combustion is a promising technology to decrease pollutant emissions and to improve combustion efficiency. A combination of air preheating and fuel dilution with combustion

Ju Pyo Kim; Uwe Schnell; Günter Scheffknecht

2008-01-01

311

Stationary Engineers Apprenticeship. Related Training Modules. 16.1-16.5 Combustion.  

ERIC Educational Resources Information Center

This learning module, one in a series of 20 related training modules for apprentice stationary engineers, deals with combustion. Addressed in the individual instructional packages included in the module are the following topics: the combustion process, types of fuel, air and flue gases, heat transfer during combustion, and wood combustion. Each…

Lane Community Coll., Eugene, OR.

312

Droplet Combustion Experiment (DCE)  

NASA Technical Reports Server (NTRS)

The first space-based experiments were performed on the combustion of free, individual liquid fuel droplets in oxidizing atmospheres. The fuel was heptane, with initial droplet diameters ranging about from 1 mm to 4 mm. The atmospheres were mixtures of helium and oxygen, at pressures of 1.00, 0.50 and 0.25 bar, with oxygen mole fractions between 20% and 40%, as well as normal Spacelab cabin air. The temperatures of the atmospheres and of the initial liquid fuel were nominally 300 K. A total of 44 droplets were burned successfully on the two flights, 8 on the shortened STS-83 mission and 36 on STS-94. The results spanned the full range of heptane droplet combustion behavior, from radiative flame extinction at larger droplet diameters in the more dilute atmospheres to diffusive extinction in the less dilute atmospheres, with the droplet disappearing prior to flame extinction at the highest oxygen concentrations. Quasisteady histories of droplet diameters were observed along with unsteady histories of flame diameters. New and detailed information was obtained on burning rates, flame characteristics and soot behavior. The results have motivated new computational and theoretical investigations of droplet combustion, improving knowledge of the chemical kinetics, fluid mechanics and heat and mass transfer processes involved in burning liquid fuels.

Haggard, John B., Jr.; Nayagan, Vedha; Dryer, Frederick L.; Williams, Forman A.

1998-01-01

313

E-Alerts: Combustion, engines, and propellants (reciprocation and rotating combustion engines). E-mail newsletter  

SciTech Connect

Design, performance, and testing of reciprocating and rotating engines of various configurations for all types of propulsion. Includes internal and external combustion engines; engine exhaust systems; engine air systems components; engine structures; stirling and diesel engines.

NONE

1999-04-01

314

Air pollution from aircraft  

NASA Technical Reports Server (NTRS)

A series of fundamental problems related to jet engine air pollution and combustion were examined. These include soot formation and oxidation, nitric oxide and carbon monoxide emissions mechanisms, pollutant dispension, flow and combustion characteristics of the NASA swirl can combustor, fuel atomization and fuel-air mixing processes, fuel spray drop velocity and size measurement, ignition and blowout. A summary of this work, and a bibliography of 41 theses and publications which describe this work, with abstracts, is included.

Heywood, J. B.; Fay, J. A.; Chigier, N. A.

1979-01-01

315

Combustion in porous media  

SciTech Connect

A 2.8-liter tube-shaped combustion vessel was constructed to study flame propagation and quenching in porous media. For this experiment, hydrogen-air flames propagating horizontally into abed of 6 mm diameter glass beads were studied. Measurements of pressure and temperature along the length of the tube were used to observe flame propagation of quenching. The critical hydrogen concentration for Hz-air mixtures was found to be 11.5%, corresponding to a critical Peclet number of Pe* = 37. This value is substantially less than the value of Pe* = 65 quoted in the literature, for example Babkin et al. (1991). It is hypothesized that buoyancy and a dependence of Pe on the Lewis number account for the discrepancy between these two results.

Dillon, J. [California Inst. of Technology, CA (US)

1999-09-01

316

Mathematics of combustion  

Microsoft Academic Search

The applications of numerical techniques to the study of combustion processes is considered. The basic equations governing combustion processes are introduced, and some novel approaches to combustion reaction modelling are described. Among the specific applications discussed are: the Burger and Korteweg-de Vries equations of detonation processes; turbulent combustion modelling; and analysis of finite amplitude waves in combustible gases.

J. D. Buckmaster; H. Rabitz; F. A. Williams; W. Fickett; J. F. Clarke

1985-01-01

317

Combustion pressure sensor  

Microsoft Academic Search

A combustion pressure sensor is described for mounting on an internal combustion engine so as to have access to the interior of a combustion cylinder. The sensor consists of: a first diaphragm means adjacent a combustion region for deflecting as a function of the magnitude of adjacent pressure in the combustion region, and for acting as a gas tight seal

Bettman

1986-01-01

318

Emissions, combustion dynamics, and control of a multiple swirl combustor  

NASA Astrophysics Data System (ADS)

To achieve single digit NOx emission from gas turbine combustors and prevent the combustion dynamics encountered in Lean Premixed Combustion, it is essential to understand the correlations among emission characteristics, combustion dynamics, and dynamics and characteristics of swirling flow field. The focus of this dissertation is to investigate the emission characteristics and combustion dynamics of multiple swirl dump combustors either in premixing or non-premixed combustion (e.g. Lean Direct Injection), and correlate these combustion characteristics (emissions, combustion instability and lean flammability) to the fluids dynamics (flow structures and its evolution). This study covers measurement of velocity flow field, temperature field, and combustion under effects of various parameters, including inlet flow Reynolds number, inlet air temperature, swirl configurations, downstream exhaust nozzle contraction ratios, length of mixing tube. These parameters are tested in both liquid and gaseous fuel combustions. Knowledge obtained through this comprehensive study is applied to passive and active controls for improving gas turbine combustion performance in the aid of novel sensor and actuator technologies. Emissions and combustion characteristics are shown closely related to the shape and size of central recirculation zone (CRZ), the mean and turbulence velocity and strain rate, and dynamics of large vortical structures. The passive controls, mostly geometry factors, affect the combustion characteristics and emissions through their influences on flow fields, and consequently temperature and radical fields. Air assist, which is used to adjust the momentum of fuel spray, is effective in reducing NOx and depress combustion oscillation without hurting LBO. Fuel distribution/split is also one important factor for achieving low NOx emission and control of combustion dynamics. The dynamics of combustion, including flame oscillations close to LBO and acoustic combustion instability, can be characterized by OH*/CH* radical oscillations and phase-locked chemiluminescence imaging. The periodic fluctuation of jet velocity and formation of large vortical structures within CRZ are responsible for combustion instability in multiple swirl combustors.

Li, Guoqiang

319

Dynamic stability, blowoff, and flame characteristics of oxy-fuel combustion  

E-print Network

Oxy-fuel combustion is a promising technology to implement carbon capture and sequestration for energy conversion to electricity in power plants that burn fossil fuels. In oxy-fuel combustion, air separation is used to ...

Shroll, Andrew Philip

2011-01-01

320

Effect of diluted and preheated oxidizer on the emission of methane flameless combustion  

NASA Astrophysics Data System (ADS)

In combustion process, reduction of emissions often accompanies with output efficiency reduction. It means, by using current combustion technique it is difficult to obtainlow pollution and high level of efficiency in the same time. In new combustion system, low NOxengines and burners are studied particularly. Recently flameless or Moderate and Intensive Low oxygen Dilution (MILD) combustion has received special attention in terms of low harmful emissions and low energy consumption. Behavior of combustion with highly preheated air was analyzed to study the change of combustion regime and the reason for the compatibility of high performance and low NOx production. Sustainability of combustion under low oxygen concentration was examined when; the combustion air temperature was above the self-ignition temperature of the fuel. This paper purposes to analyze the NOx emission quantity in conventional combustion and flameless combustion by Chemical Equilibrium with Applications (CEA) software.

Hosseini, Seyed Ehsan; Salehirad, Saber; Wahid, M. A.; Sies, Mohsin Mohd; Saat, Aminuddin

2012-06-01

321

JANNAF 37th Combustion Subcommittee Meeting. Volume 1  

NASA Technical Reports Server (NTRS)

This volume, the first of two volumes is a compilation of 59 unclassified/unlimited-distribution technical papers presented at the Joint Army-Navy-NASA-Air Force (JANNAF) 37th Combustion Subcommittee (CS) meeting held jointly with the 25th Airbreathing Propulsion Subcommittee (APS), 19th Propulsion Systems Hazards Subcommittee (PSHS), and 1st Modeling and Simulation Subcommittee (MSS) meetings. The meeting was held 13-17 November 2000 at the Naval Postgraduate School and Hyatt Regency Hotel, Monterey, California. Topics covered at the CS meeting include: a keynote address on the Future Combat Systems, and review of a new JANNAF Modeling and Simulation Subcommittee, and technical papers on gun propellant burning rate, gun tube erosion, advanced gun propulsion concepts, ETC guns, novel gun propellants; liquid, hybrid and novel propellant combustion; solid propellant combustion kinetics, GAP, ADN and RDX combustion, sandwich combustion, metal combustion, combustion instability, and motor combustion instability.

Fry, Ronald S. (Editor); Gannaway, Mary T. (Editor)

2000-01-01

322

Research on oxidation by air and tempering of Raney nickel electrocatalysts for the H2 anodes of alkali combustion materials cells. Thesis - Braunschweig Technische Univ., 1982  

NASA Technical Reports Server (NTRS)

The controlled oxidation in air of Raney nickel electrocatalysts was studied, with special attention paid to the quantitative analysis of nickel hydroxide. The content of the latter was determined through X-ray studies, thermogravimetric measurements, and spectral photometric examinations. The dependence of the content on the drying of activated catalyst is determined. The influence of nickel hydroxide on the electrochemical parameters of the catalyst, such as diffusion polarization, is studied, including a measurement of the exchange current density using the potential drop method. Conservation by oxidation in air with ancillary stabilization of the oxide in an H2 flow at 300 C is explored, including reduction by H2, the influence of tempering time, and structural studies on conserved and stabilized catalyst, long term research on the catalyst, including the influence of aging on the reduced catalyst, and the results of impedance measurements are presented.

Selbach, H. J.

1984-01-01

323

Chemical composition of air masses transported from Asia to the U.S. West Coast during ITCT 2K2: Fossil fuel combustion versus biomass-burning signatures  

Microsoft Academic Search

As part of the Intercontinental Transport and Chemical Transformation experiment in 2002 (ITCT 2K2), a National Oceanic and Atmospheric Administration (NOAA) WP-3D research aircraft was used to study the long-range transport of Asian air masses toward the west coast of North America. During research flights on 5 and 17 May, strong enhancements of carbon monoxide (CO) and other species were

J. A. de Gouw; O. R. Cooper; C. Warneke; P. K. Hudson; F. C. Fehsenfeld; J. S. Holloway; G. Hübler; D. K. Nicks Jr.; J. B. Nowak; D. D. Parrish; T. B. Ryerson; E. L. Atlas; S. G. Donnelly; S. M. Schauffler; V. Stroud; K. Johnson; G. R. Carmichael; D. G. Streets

2004-01-01

324

Air pollution and children: neural and tight junction antibodies and combustion metals, the role of barrier breakdown and brain immunity in neurodegeneration.  

PubMed

Millions of children are exposed to concentrations of air pollutants, including fine particulate matter (PM2.5), above safety standards. In the Mexico City Metropolitan Area (MCMA) megacity, children show an early brain imbalance in oxidative stress, inflammation, innate and adaptive immune response-associated genes, and blood-brain barrier breakdown. We investigated serum and cerebrospinal fluid (CSF) antibodies to neural and tight junction proteins and environmental pollutants in 139 children ages 11.91 ± 4.2 y with high versus low air pollution exposures. We also measured metals in serum and CSF. MCMA children showed significantly higher serum actin IgG, occludin/zonulin 1 IgA, IgG, myelin oligodendrocyte glycoprotein IgG and IgM (p < 0.01), myelin basic protein IgA and IgG, S-100 IgG and IgM, and cerebellar IgG (p < 0.001). Serum IgG antibodies to formaldehyde, benzene, and bisphenol A, and concentrations of Ni and Cd were significantly higher in exposed children (p < 0.001). CSF MBP antibodies and nickel concentrations were higher in MCMA children (p = 0.03). Air pollution exposure damages epithelial and endothelial barriers and is a robust trigger of tight junction and neural antibodies. Cryptic 'self' tight junction antigens can trigger an autoimmune response potentially contributing to the neuroinflammatory and Alzheimer and Parkinson's pathology hallmarks present in megacity children. The major factor determining the impact of neural antibodies is the integrity of the blood-brain barrier. Defining the air pollution linkage of the brain/immune system interactions and damage to physical and immunological barriers with short and long term neural detrimental effects to children's brains ought to be of pressing importance for public health. PMID:25147109

Calderón-Garcidueñas, Lilian; Vojdani, Aristo; Blaurock-Busch, Eleonore; Busch, Yvette; Friedle, Albrecht; Franco-Lira, Maricela; Sarathi-Mukherjee, Partha; Martínez-Aguirre, Xavier; Park, Su-Bin; Torres-Jardón, Ricardo; D'Angiulli, Amedeo

2015-01-01

325

Pulsed jet combustion generator for premixed charge engines  

DOEpatents

A method and device for generating pulsed jets which will form plumes comprising eddie structures, which will entrain a fuel/air mixture from the head space of an internal combustion engine, and mixing this fuel/air mixture with a pre-ignited fuel/air mixture of the plumes thereby causing combustion of the reactants to occur within the interior of the eddie structures.

Oppenheim, A. K. (Berkeley, CA); Stewart, H. E. (Alameda, CA); Hom, K. (Hercules, CA)

1990-01-01

326

Test Would Quantify Combustion Oxygen From Different Sources  

NASA Technical Reports Server (NTRS)

Proposed isotope-enrichment scheme enables determination of contributions of dual sources of oxygen for combustion. Liquid oxygen or other artificial stream enriched with O(18) to about 1 percent by weight. Combustion products analyzed by mass spectrometer to measure relative abundances of H2O(18) and H2O(16). From relative abundances of water products measured, one computes relative contribution of oxygen extracted from stream compared to other source of oxygen in combustion process. Used to determine contributions of natural oxygen in air and liquid oxygen supplied in separate stream mixed with air or sent directly into combustion chamber.

Tapphorn, Ralph M.

1993-01-01

327

JANNAF 36th Combustion Subcommittee Meeting. Volume 2  

NASA Technical Reports Server (NTRS)

Volume 11, the second of three volumes is a compilation of 33 unclassified/unlimited-distribution technical papers presented at the Joint Army-Navy-NASA-Air Force (JANNAF) 36th Combustion Subcommittee held jointly with the 24 Airbreathing Propulsion Subcommittee and 18th Propulsion Systems Hazards Subcommittee. The meeting was held on 18-21 October 1999 at NASA Kennedy Space Center and The DoubleTree Oceanfront Hotel, Cocoa Beach, Florida. Topics covered include gun solid propellant ignition and combustion, Electrothermal Chemical (ETC) propulsion phenomena, liquid propellant gun combustion and barrel erosion, gas phase propellant combustion, kinetic and decomposition phenomena and liquid and hybrid propellant combustion behavior.

Fry, Ronald S. (Editor); Gannaway, Mary T. (Editor)

1999-01-01

328

Internal combustion engine and method for control  

DOEpatents

In one exemplary embodiment of the invention an internal combustion engine includes a piston disposed in a cylinder, a valve configured to control flow of air into the cylinder and an actuator coupled to the valve to control a position of the valve. The internal combustion engine also includes a controller coupled to the actuator, wherein the controller is configured to close the valve when an uncontrolled condition for the internal engine is determined.

Brennan, Daniel G

2013-05-21

329

Analysis of the potential effects of air pollutants emitted during coal combustion on yellow poplar and loblolly pine and influences on mycorrhizal associations of loblolly pine  

SciTech Connect

Yellow poplar (Liriodendron tulipifera L.) and loblolly pine (Pinus taeda L.), families 2-8 and 540, seedlings were fumigated with 0.07 ppm ozone, 0.06 ppm sulfur dioxide, 0.07 ppm ozone + 0.06 ppm sulfur dioxide, 0.06 ppm sulfur dioxide + 0.10 ppm nitrogen dioxide and 0.07 ppm ozone + 0.06 ppm sulfur dioxide + 0.10 ppm nitrogen dioxide for 35 consecutive days, 6 hr/day. Control seedlings received charcoal-filtered air. Ozone or sulfur dioxide did not significantly affect height growth or dry weight of yellow poplar seedlings. All other treatments significantly reduced height growth and dry weight after 2 weeks of fumigation. Root dry weight was found to be a more sensitive indicator of air pollution stress than either shoot dry weight, height growth or visible symptoms. Loblolly pine seedlings, nonmycorrhizal and mycorrhizal with Pisolithus tinctorius, were fumigated with 0.07 ppm ozone and 0.06 ppm sulfur dioxide singly and in combination, 6 hr/day, for 35 consecutive days. Height growth of mycorrhizal and nonmycorrhizol seedlings was not affected by fumigation. Root dry weight of nonmycorrhizal seedlings was significantly reduced by all pollutant treatments in two replicate experiments. A similar reduction in root dry weight of mycorrhizal seedlings did not occur. Shoot dry weight of nonmycorrhizal seedlings was reduced in four of six pollutant treatments, and in one of six treatments of mycorrhizal seedlings. Mycorrhizal formation was extensive regardless of treatment. Apparent photosynthesis, measured every 4 days, was variable and significant differences among treatments did not occur. Total reducing sugar concentrations of roots were an inconclusive indicator of air pollutant stress.

Mahoney, M.J.

1982-01-01

330

Combustion Dynamics of Swirling Turbulent Flames  

Microsoft Academic Search

A generalized Large-Eddy Simulation (LES) methodology has been developed to simulate premixed and non-premixed gas-phase and\\u000a two-phase combustion in complex flows such as those typically encountered in gas-turbine combustors. This formulation allows\\u000a the study and analysis of the fundamental physics involved in such flows, i.e., vortex\\/flame interaction, combustion dynamics\\u000a and stability, fuel-air mixing, droplet vaporization, and other aspects of combustion.

Suresh Menon; Vaidyanathan Sankaran; Christopher Stone

2001-01-01

331

Effect of atmospheric stability on the impact of domestic wood combustion to air quality of a small urban township in winter  

NASA Astrophysics Data System (ADS)

In the winter of 2011, a field campaign was undertaken in the small township of Nelson, New Zealand to measure the vertical and horizontal distribution of concentrations of airborne particulate matter. The aim of this campaign was to improve our understanding of the causal factors which result in periods of very high concentrations of particulate pollution in small townships during winter where emissions are dominated by the combustion of wood for domestic heating. The results showed that mean hourly surface concentrations of particulates throughout the airshed were characterized by a distinctive diurnal cycle, with two peaks in concentration (one in the late evening and then, unusually, a second mid-morning). Although the timing and magnitude of hourly peak concentrations was variable throughout the valley, there was no evidence to suggest that regional or topographic flows played a significant role in the build-up of pollutants at any given location. Analysis of vertical profiles of black carbon showed that high concentrations of particulates were confined to the lowest 50 m of the boundary layer. Concentrations decreased with increasing height within this polluted surface layer. The atmosphere was very stable during the evening period. After midnight, a period of increased mixing was consistently identified throughout the lowest 100 m of the boundary layer and associated with the sudden cleansing of the surface and lower layers of the boundary layer. Throughout the observational period there was no evidence for the storage of pollutants aloft. Thus the vertical mixing of pollutants to the surface could not account for increased pollutant concentrations during the morning period. However, at this time the boundary layer remained stable and concentrations of black carbon were mixed through a very shallow layer. This suggests that despite lower domestic heating emissions in the morning, the reduced mixing volume is a likely cause of the observed marked peak in morning surface concentrations.

Grange, S. K.; Salmond, J. A.; Trompetter, W. J.; Davy, P. K.; Ancelet, T.

2013-05-01

332

Combustion chemistry  

SciTech Connect

This research is concerned with the development and use of sensitivity analysis tools to probe the response of dependent variables to model input variables. Sensitivity analysis is important at all levels of combustion modeling. This group`s research continues to be focused on elucidating the interrelationship between features in the underlying potential energy surface (obtained from ab initio quantum chemistry calculations) and their responses in the quantum dynamics, e.g., reactive transition probabilities, cross sections, and thermal rate coefficients. The goals of this research are: (i) to provide feedback information to quantum chemists in their potential surface refinement efforts, and (ii) to gain a better understanding of how various regions in the potential influence the dynamics. These investigations are carried out with the methodology of quantum functional sensitivity analysis (QFSA).

Brown, N.J. [Lawrence Berkeley Laboratory, CA (United States)

1993-12-01

333

Combustion Byproducts Recycling Consortium  

SciTech Connect

Each year, over 100 million tons of solid byproducts are produced by coal-burning electric utilities in the United States. Annual production of flue gas desulfurization (FGD) byproducts continues to increase as the result of more stringent sulfur emission restrictions. In addition, stricter limits on NOx emissions mandated by the 1990 Clean Air Act have resulted in utility burner/boiler modifications that frequently yield higher carbon concentrations in fly ash, which restricts the use of the ash as a cement replacement. Controlling ammonia in ash is also of concern. If newer, 'clean coal' combustion and gasification technologies are adopted, their byproducts may also present a management challenge. The objective of the Combustion Byproducts Recycling Consortium (CBRC) is to develop and demonstrate technologies to address issues related to the recycling of byproducts associated with coal combustion processes. A goal of CBRC is that these technologies, by the year 2010, will lead to an overall ash utilization rate from the current 34% to 50% by such measures as increasing the current rate of FGD byproduct use and increasing in the number of uses considered 'allowable' under state regulations. Another issue of interest to the CBRC would be to examine the environmental impact of both byproduct utilization and disposal. No byproduct utilization technology is likely to be adopted by industry unless it is more cost-effective than landfilling. Therefore, it is extremely important that the utility industry provide guidance to the R&D program. Government agencies and private-sector organizations that may be able to utilize these materials in the conduct of their missions should also provide input. The CBRC will serve as an effective vehicle for acquiring and maintaining guidance from these diverse organizations so that the proper balance in the R&D program is achieved.

Paul Ziemkiewicz; Tamara Vandivort; Debra Pflughoeft-Hassett; Y. Paul Chugh; James Hower

2008-08-31

334

Combustion Byproducts Recycling Consortium  

SciTech Connect

Each year, over 100 million tons of solid byproducts are produced by coal-burning electric utilities in the United States. Annual production of flue gas desulfurization (FGD) byproducts continues to increase as the result of more stringent sulfur emission restrictions. In addition, stricter limits on NOx emissions mandated by the 1990 Clean Air Act have resulted in utility burner/boiler modifications that frequently yield higher carbon concentrations in fly ash, which restricts the use of the ash as a cement replacement. Controlling ammonia in ash is also of concern. If newer, “clean coal” combustion and gasification technologies are adopted, their byproducts may also present a management challenge. The objective of the Combustion Byproducts Recycling Consortium (CBRC) is to develop and demonstrate technologies to address issues related to the recycling of byproducts associated with coal combustion processes. A goal of CBRC is that these technologies, by the year 2010, will lead to an overall ash utilization rate from the current 34% to 50% by such measures as increasing the current rate of FGD byproduct use and increasing in the number of uses considered “allowable” under state regulations. Another issue of interest to the CBRC would be to examine the environmental impact of both byproduct utilization and disposal. No byproduct utilization technology is likely to be adopted by industry unless it is more cost-effective than landfilling. Therefore, it is extremely important that the utility industry provide guidance to the R&D program. Government agencies and privatesector organizations that may be able to utilize these materials in the conduct of their missions should also provide input. The CBRC will serve as an effective vehicle for acquiring and maintaining guidance from these diverse organizations so that the proper balance in the R&D program is achieved.

Ziemkiewicz, Paul; Vandivort, Tamara; Pflughoeft-Hassett, Debra; Chugh, Y Paul; Hower, James

2008-08-31

335

Fluids and Combustion Facility: Combustion Integrated Rack Modal Model Correlation  

NASA Technical Reports Server (NTRS)

The Fluids and Combustion Facility (FCF) is a modular, multi-user, two-rack facility dedicated to combustion and fluids science in the US Laboratory Destiny on the International Space Station. FCF is a permanent facility that is capable of accommodating up to ten combustion and fluid science investigations per year. FCF research in combustion and fluid science supports NASA's Exploration of Space Initiative for on-orbit fire suppression, fire safety, and space system fluids management. The Combustion Integrated Rack (CIR) is one of two racks in the FCF. The CIR major structural elements include the International Standard Payload Rack (ISPR), Experiment Assembly (optics bench and combustion chamber), Air Thermal Control Unit (ATCU), Rack Door, and Lower Structure Assembly (Input/Output Processor and Electrical Power Control Unit). The load path through the rack structure is outlined. The CIR modal survey was conducted to validate the load path predicted by the CIR finite element model (FEM). The modal survey is done by experimentally measuring the CIR frequencies and mode shapes. The CIR model was test correlated by updating the model to represent the test mode shapes. The correlated CIR model delivery is required by NASA JSC at Launch-10.5 months. The test correlated CIR flight FEM is analytically integrated into the Shuttle for a coupled loads analysis of the launch configuration. The analysis frequency range of interest is 0-50 Hz. A coupled loads analysis is the analytical integration of the Shuttle with its cargo element, the Mini Payload Logistics Module (MPLM), in the Shuttle cargo bay. For each Shuttle launch configuration, a verification coupled loads analysis is performed to determine the loads in the cargo bay as part of the structural certification process.

McNelis, Mark E.; Suarez, Vicente J.; Sullivan, Timothy L.; Otten, Kim D.; Akers, James C.

2005-01-01

336

Combustion Fundamentals Research  

NASA Technical Reports Server (NTRS)

Increased emphasis is placed on fundamental and generic research at Lewis Research Center with less systems development efforts. This is especially true in combustion research, where the study of combustion fundamentals has grown significantly in order to better address the perceived long term technical needs of the aerospace industry. The main thrusts for this combustion fundamentals program area are as follows: analytical models of combustion processes, model verification experiments, fundamental combustion experiments, and advanced numeric techniques.

1983-01-01

337

Constant-Pressure Combustion Charts Including Effects of Diluent Addition  

NASA Technical Reports Server (NTRS)

Charts are presented for the calculation of (a) the final temperatures and the temperature changes involved in constant-pressure combustion processes of air and in products of combustion of air and hydrocarbon fuels, and (b) the quantity of hydrocarbon fuels required in order to attain a specified combustion temperature when water, alcohol, water-alcohol mixtures, liquid ammonia, liquid carbon dioxide, liquid nitrogen, liquid oxygen, or their mixtures are added to air as diluents or refrigerants. The ideal combustion process and combustion with incomplete heat release from the primary fuel and from combustible diluents are considered. The effect of preheating the mixture of air and diluents and the effect of an initial water-vapor content in the combustion air on the required fuel quantity are also included. The charts are applicable only to processes in which the final mixture is leaner than stoichiometric and at temperatures where dissociation is unimportant. A chart is also included to permit the calculation of the stoichiometric ratio of hydrocarbon fuel to air with diluent addition. The use of the charts is illustrated by numerical examples.

Turner, L Richard; Bogart, Donald

1949-01-01

338

Plasma igniter for internal combustion engine  

NASA Technical Reports Server (NTRS)

An igniter for the air/fuel mixture used in the cylinders of an internal combustion engine is described. A conventional spark is used to initiate the discharge of a large amount of energy stored in a capacitor. A high current discharge of the energy in the capacitor switched on by a spark discharge produces a plasma and a magnetic field. The resultant combined electromagnetic current and magnetic field force accelerates the plasma deep into the combustion chamber thereby providing an improved ignition of the air/fuel mixture in the chamber.

Fitzgerald, D. J.; Breshears, R. R. (inventors)

1978-01-01

339

A laboratory scale supersonic combustive flow system  

SciTech Connect

A laboratory scale supersonic flow system [Combustive Flow System (CFS)] which utilizes the gaseous products of methane-air and/or liquid fuel-air combustion has been assembled to provide a propulsion type exhaust flow field for various applications. Such applications include providing a testbed for the study of planar two-dimensional nozzle flow fields with chemistry, three-dimensional flow field mixing near the exit of rectangular nozzles, benchmarking the predictive capability of various computational fluid dynamic codes, and the development and testing of advanced diagnostic techniques. This paper will provide a detailed description of the flow system and data related to its operation.

Sams, E.C.; Zerkle, D.K.; Fry, H.A.; Wantuck, P.J.

1995-02-01

340

Combustion instability modeling and analysis  

SciTech Connect

It is well known that the two key elements for achieving low emissions and high performance in a gas turbine combustor are to simultaneously establish (1) a lean combustion zone for maintaining low NO{sub x} emissions and (2) rapid mixing for good ignition and flame stability. However, these requirements, when coupled with the short combustor lengths used to limit the residence time for NO formation typical of advanced gas turbine combustors, can lead to problems regarding unburned hydrocarbons (UHC) and carbon monoxide (CO) emissions, as well as the occurrence of combustion instabilities. The concurrent development of suitable analytical and numerical models that are validated with experimental studies is important for achieving this objective. A major benefit of the present research will be to provide for the first time an experimentally verified model of emissions and performance of gas turbine combustors. The present study represents a coordinated effort between industry, government and academia to investigate gas turbine combustion dynamics. Specific study areas include development of advanced diagnostics, definition of controlling phenomena, advancement of analytical and numerical modeling capabilities, and assessment of the current status of our ability to apply these tools to practical gas turbine combustors. The present work involves four tasks which address, respectively, (1) the development of a fiber-optic probe for fuel-air ratio measurements, (2) the study of combustion instability using laser-based diagnostics in a high pressure, high temperature flow reactor, (3) the development of analytical and numerical modeling capabilities for describing combustion instability which will be validated against experimental data, and (4) the preparation of a literature survey and establishment of a data base on practical experience with combustion instability.

Santoro, R.J.; Yang, V.; Santavicca, D.A. [Pennsylvania State Univ., University Park, PA (United States); Sheppard, E.J. [Tuskeggee Univ., Tuskegee, AL (United States). Dept. of Aerospace Engineering

1995-12-31

341

Observing and modeling nonlinear dynamics in an internal combustion engine  

Microsoft Academic Search

We propose a low-dimensional, physically motivated, nonlinear map as a model for cyclic combustion variation in spark-ignited internal combustion engines. A key feature is the interaction between stochastic, small-scale fluctuations in engine parameters and nonlinear deterministic coupling between successive engine cycles. Residual cylinder gas from each cycle alters the in-cylinder fuel-air ratio and thus the combustion efficiency in succeeding cycles.

C. S. Daw; M. B. Kennel; C. E. Finney; F. T. Connolly

1998-01-01

342

Exhaust gas purifying system for internal combustion engines  

Microsoft Academic Search

An exhaust gas purifying system of the type utilizing a threeway catalyst containing an oxygen storage material includes an electronic control unit for controlling the amount of secondary air supplied to the exhaust system of an internal combustion engine. The electronic control unit receives a signal from an exhaust air-fuel ratio sensor indicative of an air-fuel ratio of the exhaust

T. Hattori; K. Kondo; J. Naito; T. Nakase

1980-01-01

343

Stoichiometric Experiments with Alkane Combustion: A Classroom Demonstration  

ERIC Educational Resources Information Center

A simple, effective demonstration of the concept of limiting and excess reagent is presented. Mixtures of either air/methane (from a gas line) or air/butane (from a disposable cigarette lighter) contained in a plastic 2 L soda bottles are ignited. The mixtures combust readily when air/fuel ratios are stoichiometric, but not at a 2-fold excess of…

Zhilin, Denis M.

2012-01-01

344

Anti-pollution system for internal combustion and diesel engines  

Microsoft Academic Search

An anti-pollution system for an internal combustion engine wherein a container within which is a body of water has an air injection system including first tubing extending into the container, second tubing connected to extract combustion gases from the engine exhaust system to introduce them into the container, third tubing extending from within the container to the engine intake system

Martinez-delgado

1982-01-01

345

DEMONSTRATION BULLETIN: THE PYRETRON OXYGEN BURNER, AMERICAN COMBUSTION TECHNOLOGIES, INC.  

EPA Science Inventory

The Pyretron is a burner which is designed to allow for the injection of oxygen into the combustion air stream for the purpose of increasing the efficiency of a hazardous waste incinerator. The SITE demonstration of the Pyretron took place at the U.S. EPA's Combustion Re...

346

Application of data mining in boiler combustion optimization  

Microsoft Academic Search

In order to improve boiler efficiency and reduce NOx emissions of a coal-fired boiler, a new solution strategy of combustion optimization is proposed is this paper. The key point of combustion optimization is the optimal setpoints of fuel and air parameters. As the development of electric industry, large amounts of history data are accumulated and data mining technique is applied

Ting-ting Yang; Ji-zhen Liu; De-liang Zeng; Xie Xie

2010-01-01

347

Relationship between pulmonary function and indoor air pollution from coal combustion among adult residents in an inner-city area of southwest China  

PubMed Central

Few studies evaluate the amount of particulate matter less than 2.5 mm in diameter (PM2.5) in relation to a change in lung function among adults in a population. The aim of this study was to assess the association of coal as a domestic energy source to pulmonary function in an adult population in inner-city areas of Zunyi city in China where coal use is common. In a cross-sectional study of 104 households, pulmonary function measurements were assessed and compared in 110 coal users and 121 non-coal users (?18 years old) who were all nonsmokers. Several sociodemographic factors were assessed by questionnaire, and ventilatory function measurements including forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1), the FEV1/FVC ratio, and peak expiratory flow rate (PEFR) were compared between the 2 groups. The amount of PM2.5 was also measured in all residences. There was a significant increase in the relative concentration of PM2.5 in the indoor kitchens and living rooms of the coal-exposed group compared to the non-coal-exposed group. In multivariate analysis, current exposure to coal smoke was associated with a 31.7% decrease in FVC, a 42.0% decrease in FEV1, a 7.46% decrease in the FEV1/FVC ratio, and a 23.1% decrease in PEFR in adult residents. The slope of lung function decrease for Chinese adults is approximately a 2-L decrease in FVC, a 3-L decrease in FEV1, and an 8 L/s decrease in PEFR per count per minute of PM2.5 exposure. These results demonstrate the harmful effects of indoor air pollution from coal smoke on the lung function of adult residents and emphasize the need for public health efforts to decrease exposure to coal smoke. PMID:25296361

Jie, Y.; Houjin, H.; Xun, M.; Kebin, L.; Xuesong, Y.; Jie, X.

2014-01-01

348

TOXIC SUBSTANCES FROM COAL COMBUSTION  

SciTech Connect

The Clean Air Act Amendments of 1990 identify a number of hazardous air pollutants (HAPs) as candidates for regulation. Should regulations be imposed on HAP emissions from coal-fired power plants, a sound understanding of the fundamental principles controlling the formation and partitioning of toxic species during coal combustion will be needed. With support from the Federal Energy Technology Center (FETC), the Electric Power Research Institute, and VTT (Finland), Physical Sciences Inc. (PSI) has teamed with researchers from USGS, MIT, the University of Arizona (UA), the University of Kentucky (UK), the University of Connecticut (UC), the University of Utah (UU) and the University of North Dakota Energy and Environ-mental Research Center (EERC) to develop a broadly applicable emissions model useful to regulators and utility planners. The new Toxics Partitioning Engineering Model (ToPEM) will be applicable to all combustion conditions including new fuels and coal blends, low-NOx combustion systems, and new power generation plants. Development of ToPEM will be based on PSI's existing Engineering Model for Ash Formation (EMAF). This report covers the reporting period from 1 January 1999 to 31 March 1999. During this period, a full Program Review Meeting was held at the University of Arizona. At this meeting, the progress of each group was reviewed, plans for the following 9 month period were discussed, and action items (principally associated with the transfer of samples and reports among the various investigators) were identified.

Kolker, A.; Sarofim, A.F.; Palmer, C.A.; Huggins, F.E.; Huffman, G.P.; Lighty, J.; Veranth, J.; Helble, J.J.; Wendt, J.O.L.; Ames, M.R.; Finkelman, R.; Mamani-Paco, M.; Sterling, R.; Mroczkowsky, S.J.; Panagiotou, T.; Seames, W.

1999-05-10

349

Coal-water slurry fuel internal combustion engine and method for operating same  

DOEpatents

An internal combustion engine fueled with a coal-water slurry is described. About 90 percent of the coal-water slurry charge utilized in the power cycle of the engine is directly injected into the main combustion chamber where it is ignited by a hot stream of combustion gases discharged from a pilot combustion chamber of a size less than about 10 percent of the total clearance volume of main combustion chamber with the piston at top dead center. The stream of hot combustion gases is provided by injecting less than about 10 percent of the total coal-water slurry charge into the pilot combustion chamber and using a portion of the air from the main combustion chamber that has been heated by the walls defining the pilot combustion chamber as the ignition source for the coal-water slurry injected into the pilot combustion chamber.

McMillian, Michael H. (Fairmont, WV)

1992-01-01

350

Comparison of carbon capture IGCC with pre-combustion decarbonisation and with chemical-looping combustion  

Microsoft Academic Search

Carbon capture from conventional power cycles is accompanied by a significant loss of efficiency. One process concept with a potential for better performance is chemical-looping combustion (CLC). CLC uses a metal oxide to oxidize the fuel, and the reduced metal is then re-oxidized in a second reactor with air. The combustion products CO2 and water remain unmixed with nitrogen, thereby

B. Erlach; M. Schmidt; G. Tsatsaronis

2011-01-01

351

Combustion Technology Development for an Advanced Glass Melting System  

E-print Network

Concept feasibility of an innovative technology for glass production has recently been demonstrated. It is based on suspension heating of the glass-forming batch minerals while entrained in a combustion flow of preheated air and natural gas...

Stickler, D. B.; Westra, L.; Woodroffe, J.; Jeong, K. M.; Donaldson, L. W.

352

SURVEY AND ANALYSIS OF CURRENT EUROPEAN TECHNOLOGIES FOR WOOD COMBUSTION  

EPA Science Inventory

The report summarizes current technologies and air pollution policies pertaining to wood combustion. Twenty different concepts for wood burning equipment are described. Also included are section diagrams, size ranges, and comments regarding efficiency and convenience. Many of the...

353

HCCI Combustion Phasing with Closed-Loop Combustion Control Using Variable Compression Ratio in a Multi Cylinder Engine  

Microsoft Academic Search

This study applies Closed-Loop Combustion Control (CLCC) using Variable Compression Ratio (VCR) and cylinder balancing using variable lambda to solve the problem. Step changes of set points for combustion phasing, Compression Ratio (CR), and load together with ramps of engine speed and inlet air temperature are investigated. Performances of the controllers are investigated by running the engine at either a

Göran Haraldsson; Bengt Johansson; Jari Hyvönen; Saab Automobile Powertrain

354

Chemical Looping Combustion Kinetics  

SciTech Connect

One of the most promising methods of capturing CO{sub 2} emitted by coal-fired power plants for subsequent sequestration is chemical looping combustion (CLC). A powdered metal oxide such as NiO transfers oxygen directly to a fuel in a fuel reactor at high temperatures with no air present. Heat, water, and CO{sub 2} are released, and after H{sub 2}O condensation the CO{sub 2} (undiluted by N{sub 2}) is ready for sequestration, whereas the nickel metal is ready for reoxidation in the air reactor. In principle, these processes can be repeated endlessly with the original nickel metal/nickel oxide participating in a loop that admits fuel and rejects ash, heat, and water. Our project accumulated kinetic rate data at high temperatures and elevated pressures for the metal oxide reduction step and for the metal reoxidation step. These data will be used in computational modeling of CLC on the laboratory scale and presumably later on the plant scale. The oxygen carrier on which the research at Utah is focused is CuO/Cu{sub 2}O rather than nickel oxide because the copper system lends itself to use with solid fuels in an alternative to CLC called 'chemical looping with oxygen uncoupling' (CLOU).

Edward Eyring; Gabor Konya

2009-03-31

355

Performance calculations for 1000 MWe MHD/steam power plants  

NASA Technical Reports Server (NTRS)

The effects of MHD generator operating conditions and constraints on the performance of MHD/steam power plants are investigated. Power plants using high temperature combustion air preheat (2500 F) and plants using intermediate temperature preheat (1100 F) with oxygen enrichment are considered. Variations of these two types of power plants are compared on the basis of fixed total electrical output (1000 MWe). Results are presented to show the effects of generator plant length and level of oxygen enrichment on the plant thermodynamic efficiency and on the required generator mass flow rate. Factors affecting the optimum levels of oxygen enrichment are analyzed. It is shown that oxygen enrichment can reduce magnet stored energy requirement.

Pian, C. C. P.

1981-01-01

356

Methods and systems for combustion dynamics reduction  

DOEpatents

Methods and systems for combustion dynamics reduction are provided. A combustion chamber may include a first premixer and a second premixer. Each premixer may include at least one fuel injector, at least one air inlet duct, and at least one vane pack for at least partially mixing the air from the air inlet duct or ducts and fuel from the fuel injector or injectors. Each vane pack may include a plurality of fuel orifices through which at least a portion of the fuel and at least a portion of the air may pass. The vane pack or packs of the first premixer may be positioned at a first axial position and the vane pack or packs of the second premixer may be positioned at a second axial position axially staggered with respect to the first axial position.

Kraemer, Gilbert Otto (Greer, SC); Varatharajan, Balachandar (Cincinnati, OH); Srinivasan, Shiva (Greer, SC); Lynch, John Joseph (Wilmington, NC); Yilmaz, Ertan (Albany, NY); Kim, Kwanwoo (Greer, SC); Lacy, Benjamin (Greer, SC); Crothers, Sarah (Greenville, SC); Singh, Kapil Kumar (Rexford, NY)

2009-08-25

357

High efficiency detonation internal combustion engine (DICE)  

NASA Astrophysics Data System (ADS)

Controlled detonation combustion could be used in future internal combustion engines to achieve high cycle efficiency and minimize NO(x) formation, if conventional design limitations are removed. An engine is proposed that uses a separate detonation combustion chamber which discharges tangentially into an expansion chamber formed by the piston and cylinder at top dead center. The expansion chamber is designed to efficiently store a portion of the detonation wave's kinetic energy in the form of a vortex, which is subsequently converted into static pressure. The rapid burning, followed by 'leaning' through mixing with air in the vortex chamber, may reduce the formation of NO(x) and unburned hydrocarbons as compared to conventional combustion. The thermodynamic aspects of detonation combustion compared to either constant volume or constant pressure combustion yield a significant increase in combustion compression ratio for fuels such as natural gas. The shock wave propagation through the vortex chamber is described with a shock-capturing finite element Euler flow code supporting the premise of vortex storage and rapid-mixing characteristics.

Loth, Eric; Loth, John; Loth, Frank

1992-07-01

358

Single free-piston external combustion engine with hydraulic piston detection  

Microsoft Academic Search

An external combustion engine is described comprising: a combustion member including a sleeve having an end closure and an ignition means at each end thereof, inlet and outlet valving means for introducing compressed air and exhausting combusted gases through each end closure, and a free piston mounted in the sleeve for sliding reciprocating axial motion between the end closures and

1987-01-01

359

3D calculations of reacting flows within aircraft engine combustion chambers  

Microsoft Academic Search

Some three-dimensional calculations have been worked out in the case of an aircraft engine combustion chamber containing one swirling fuel-air injector and four primary holes. The influence of the grid size and of some parameters of the combustion and turbulence models has been investigated. The combustion efficiency is relatively unsensitive to the grid size unlike the maximum wall temperature and

F. Pit; H. Tichtinsky; F. Dupoirieux

1989-01-01

360

Combustion 2000  

SciTech Connect

This report presents work carried out under contract DE-AC22-95PC95144 ''Combustion 2000 - Phase II.'' The goals of the program are to develop a coal-fired high performance power generation system (HIPPS) that is capable of: {lg_bullet} thermal efficiency (HHV) {ge} 47% {lg_bullet} NOx, SOx, and particulates {le} 10% NSPS (New Source Performance Standard) {lg_bullet} coal providing {ge} 65% of heat input {lg_bullet} all solid wastes benign {lg_bullet} cost of electricity {le} 90% of present plants Phase I, which began in 1992, focused on the analysis of various configurations of indirectly fired cycles and on technical assessments of alternative plant subsystems and components, including performance requirements, developmental status, design options, complexity and reliability, and capital and operating costs. Phase I also included preliminary R&D and the preparation of designs for HIPPS commercial plants approximately 300 MWe in size. Phase II, had as its initial objective the development of a complete design base for the construction and operation of a HIPPS prototype plant to be constructed in Phase III. As part of a descoping initiative, the Phase III program has been eliminated and work related to the commercial plant design has been ended. The rescoped program retained a program of engineering research and development focusing on high temperature heat exchangers, e.g. HITAF development (Task 2); a rescoped Task 6 that is pertinent to Vision 21 objectives and focuses on advanced cycle analysis and optimization, integration of gas turbines into complex cycles, and repowering designs; and preparation of the Phase II Technical Report (Task 8). This rescoped program deleted all subsystem testing (Tasks 3, 4, and 5) and the development of a site-specific engineering design and test plan for the HIPPS prototype plant (Task 7). Work reported herein is from: {lg_bullet} Task 2.2.4 Pilot Scale Testing {lg_bullet} Task 2.2.5.2 Laboratory and Bench Scale Activities

None

1999-12-31

361

Fluidized bed coal combustion reactor  

NASA Technical Reports Server (NTRS)

A fluidized bed coal reactor includes a combination nozzle-injector ash-removal unit formed by a grid of closely spaced open channels, each containing a worm screw conveyor, which function as continuous ash removal troughs. A pressurized air-coal mixture is introduced below the unit and is injected through the elongated nozzles formed by the spaces between the channels. The ash build-up in the troughs protects the worm screw conveyors as does the cooling action of the injected mixture. The ash layer and the pressure from the injectors support a fluidized flame combustion zone above the grid which heats water in boiler tubes disposed within and/or above the combustion zone and/or within the walls of the reactor.

Moynihan, P. I.; Young, D. L. (inventors)

1981-01-01

362

Fundamentals of Gas Turbine combustion  

NASA Technical Reports Server (NTRS)

Combustion problems and research recommendations are discussed in the areas of atomization and vaporization, combustion chemistry, combustion dynamics, and combustion modelling. The recommendations considered of highest priority in these areas are presented.

Gerstein, M.

1979-01-01

363

Modeling coal combustion behavior in an ironmaking blast furnace raceway: model development and applications  

SciTech Connect

A numerical model has been developed and validated for the investigation of coal combustion phenomena under blast furnace operating conditions. The model is fully three-dimensional, with a broad capacity to analyze significant operational and equipment design changes. The model was used in a number of studies, including: Effect of cooling gas type in coaxial lance arrangements. It was found that oxygen cooling improves coal burnout by 7% compared with natural gas cooling under conditions that have the same amount of oxygen enrichment in the hot blast. Effect of coal particle size distribution. It was found that during two similar periods of operation at Port Kembla's BF6, a difference in PCI capability could be attributed to the difference in coal size distribution. Effect of longer tuyeres. Longer tuyeres were installed at Port Kembla's BF5, leading to its reline scheduled for March 2009. The model predicted an increase in blast velocity at the tuyere nose due to the combustion of volatiles within the tuyere, with implications for tuyere pressure drop and PCI capability. Effect of lance tip geometry. A number of alternate designs were studied, with the best-performing designs promoting the dispersion of the coal particles. It was also found that the base case design promoted size segregation of the coal particles, forcing smaller coal particles to one side of the plume, leaving larger coal particles on the other side. 11 refs., 15 figs., 4 tabs.

Maldonado, D.; Austin, P.R.; Zulli, P.; Guo B. [BlueScope Steel Research Laboratories, Port Kembla, NSW (Australia)

2009-03-15

364

AIR POLLUTION TECHNOLOGY BRANCH (AIR POLLUTION PREVENTION AND CONTROL DIVISION, NRMRL)  

EPA Science Inventory

Fundamental and applied combustion research has been conducted by the Air Pollution Prevention and Control Division's Air Pollution Technology Branch (APTB)and its predecessors since EPA's inception. APTB has been instrumental in the development and successful application of flue...

365

Coal combustion waste management study  

SciTech Connect

Coal-fired generation accounted for almost 55 percent of the production of electricity in the United States in 1990. Coal combustion generates high volumes of ash and flue gas desulfurization (FGD) wastes, estimated at almost 90 million tons. The amount of ash and flue gas desulfurization wastes generated by coal-fired power plants is expected to increase as a result of future demand growth, and as more plants comply with Title IV of the 1990 Clean Air Act Amendments. Nationwide, on average, over 30 percent of coal combustion wastes is currently recycled for use in various applications; the remaining percentage is ultimately disposed in waste management units. There are a significant number of on-site and off-site waste management units that are utilized by the electric utility industry to store or dispose of coal combustion waste. Table ES-1 summarizes the number of disposal units and estimates of waste contained at these unites by disposal unit operating status (i.e, operating or retired). Further, ICF Resources estimates that up to 120 new or replacement units may need to be constructed to service existing and new coal capacity by the year 2000. The two primary types of waste management units used by the industry are landfills and surface impoundments. Utility wastes have been exempted by Congress from RCRA Subtitle C hazardous waste regulation since 1980. As a result of this exemption, coal combustion wastes are currently being regulated under Subtitle D of RCRA. As provided under Subtitle D, wastes not classified as hazardous under Subtitle C are subject to State regulation. At the same time Congress developed this exemption, also known as the ``Bevill Exclusion,`` it directed EPA to prepare a report on coal combustion wastes and make recommendations on how they should be managed.

Not Available

1993-02-01

366

Combustion Modeling in Internal Combustion Engines  

Microsoft Academic Search

The fundamental assumptions of the Blizard and Keck combustion model for internal combustion engines are examined and a generalization of that model is derived. The most significant feature of the model is that it permits the occurrence of unburned hydrocarbons in the thermodynamic-kinetic modeling of exhaust gases. The general formulas are evaluated in two specific cases that are likely to

FRANK J. ZELEZNIK

1976-01-01

367

AN OVERVIEW OF EPA'S COMBUSTION RESEARCH PROGRAM  

EPA Science Inventory

The Air Pollution Technology Branch (APTB) of the U.S. Environmental Protection Agency's National Risk Management Research Laboratory, located in Research Triangle Park, North Carolina, performs a variety of combustion related research. Currently APTB's focus is on mercury from c...

368

Hydrogen-oxygen powered internal combustion engine  

NASA Technical Reports Server (NTRS)

Hydrogen at 300 psi and oxygen at 800 psi are injected sequentially into the combustion chamber to form hydrogen-rich mixture. This mode of injection eliminates difficulties of preignition, detonation, etc., encountered with carburated, spark-ignited, hydrogen-air mixtures. Ignition at startup is by means of a palladium catalyst.

Cameron, H.; Morgan, N.

1970-01-01

369

CONTROLLING EMISSIONS FROM FUEL AND WASTE COMBUSTION  

EPA Science Inventory

Control of emissions from combustion of fuels and wastes has been a traditional focus of air pollution regulations. Significant technology developments of the '50s and '60s have been refined into reliable chemical and physical process unit operations. In the U.S., acid rain legis...

370

Combustion characteristics of gas turbine alternative fuels  

NASA Technical Reports Server (NTRS)

An experimental investigation was conducted to obtain combustion performance values for specific heavyend, synthetic hydrocarbon fuels. A flame tube combustor modified to duplicate an advanced gas turbine engine combustor was used for the tests. Each fuel was tested at steady-state operating conditions over a range of mass flow rates, fuel-to-air mass ratio, and inlet air temperatures. The combustion pressure, as well as the hardware, were kept nearly constant over the program test phase. Test results were obtained in regards to geometric temperature pattern factors as a function of combustor wall temperatures, the combustion gas temperature, and the combustion emissions, both as affected by the mass flow rate and fuel-to-air ratio. The synthetic fuels were reacted in the combustor such that for most tests their performance was as good, if not better, than the baseline gasoline or diesel fuel tests. The only detrimental effects were that at high inlet air temperature conditions, fuel decomposition occurred in the fuel atomizing nozzle passages resulting in blockage. And the nitrogen oxide emissions were above EPA limits at low flow rate and high operating temperature conditions.

Rollbuhler, R. James

1987-01-01

371

APTI Course 427, Combustion Evaluation. Instructor's Guide.  

ERIC Educational Resources Information Center

This instructor's manual provides lesson plans for the teaching of a course in combustion evaluation in control of air pollution. It includes: (1) an introduction, (2) goals, (3) instructional objectives, (4) course background, (5) course agenda, (6) prerequisite skills, (7) intended student population, (8) course presentation, (9) texts and…

Beard, J. Taylor; And Others

372

The Combustion of Methane at High Temperatures  

Microsoft Academic Search

The combustion at about 1000 degrees C of methane\\/air mixtures containing up to 5% of methane has been studied using a flow system. Under such conditions the reaction takes place in a few milliseconds. It is little influenced by surface, is retarded by methane and accelerated by oxygen. Below 500 to 600 degrees C there appears to be a change

J. H. Burgoyne; H. Hirsch

1954-01-01

373

Internal combustion engine  

Microsoft Academic Search

An internal combustion engine is described which utilizes a combustion cylinder formed in part of material which can withstand high temperatures in conjunction with a displacement or power piston having a ringless section capable of withstanding high temperatures and being backed up by a relatively low temperature lubricated ringed piston section. Means to inject fuel and water into the combustion

Thomas

1976-01-01

374

Combustion synthesis and nanomaterials  

Microsoft Academic Search

The recent developments and trends in combustion science towards the synthesis of nanomaterials are discussed. Different modifications made to conventional combustion approaches for preparation of nanomaterials are critically analyzed. Special attention is paid to various applications of combustion synthesized nanosized products.

Singanahally T. Aruna; Alexander S. Mukasyan

2008-01-01

375

Oxy-Combustion Boiler Material Development  

SciTech Connect

Under U.S. Department of Energy Cooperative Agreement No. DE-NT0005262 Foster Wheeler North America Corp conducted a laboratory test program to determine the effect of oxy-combustion on boiler tube corrosion. In this program, CFD modeling was used to predict the gas compositions that will exist throughout and along the walls of air-fired and oxy-fired boilers operating with low to high sulfur coals. Test coupons of boiler tube materials were coated with deposits representative of those coals and exposed to the CFD predicted flue gases for up to 1000 hours. The tests were conducted in electric tube furnaces using oxy-combustion and air-fired flue gases synthesized from pressurized cylinders. Following exposure, the test coupons were evaluated to determine the total metal wastage experienced under air and oxy-combustions conditions and materials recommendations were made. Similar to air-fired operation, oxy-combustion corrosion rates were found to vary with the boiler material, test temperature, deposit composition, and gas composition. Despite this, comparison of air-fired and oxy-fired corrosion rates showed that oxy-firing rates were, for the most part, similar to, if not lower than those of air-firing; this finding applied to the seven furnace waterwall materials (wrought and weld overlay) and the ten superheater/reheater materials (wrought and weld overlay) that were tested. The results of the laboratory oxy-combustion tests, which are based on a maximum bulk flue gas SO2 level of 3200 ppmv (wet) / 4050 ppmv (dry), suggest that, from a corrosion standpoint, the materials used in conventional subcritical and supercritical, air-fired boilers should also be suitable for oxy-combustion retrofits. Although the laboratory test results are encouraging, they are only the first step of a material evaluation process and it is recommended that follow-on corrosion tests be conducted in coal-fired boilers operating under oxy-combustion to provide longer term (one to two year) data. The test program details and data are presented herein.

Gagliano, Michael; Seltzer, Andrew; Agarwal, Hans; Robertson, Archie; Wang, Lun

2012-01-31

376

Oxy-Combustion Boiler Material Development  

SciTech Connect

Under U.S. Department of Energy Cooperative Agreement No. DE-NT0005262 Foster Wheeler North America Corp conducted a laboratory test program to determine the effect of oxy-combustion on boiler tube corrosion. In this program, CFD modeling was used to predict the gas compositions that will exist throughout and along the walls of air-fired and oxy-fired boilers operating with low to high sulfur coals. Test coupons of boiler tube materials were coated with deposits representative of those coals and exposed to the CFD predicted flue gases for up to 1000 hours. The tests were conducted in electric tube furnaces using oxy-combustion and air-fired flue gases synthesized from pressurized cylinders. Following exposure, the test coupons were evaluated to determine the total metal wastage experienced under air and oxy-combustions conditions and materials recommendations were made. Similar to air-fired operation, oxy-combustion corrosion rates were found to vary with the boiler material, test temperature, deposit composition, and gas composition. Despite this, comparison of air-fired and oxy-fired corrosion rates showed that oxy-firing rates were, for the most part, similar to, if not lower than those of air-firing; this finding applied to the seven furnace waterwall materials (wrought and weld overlay) and the ten superheater/reheater materials (wrought and weld overlay) that were tested. The results of the laboratory oxy-combustion tests, which are based on a maximum bulk flue gas SO{sub 2} level of 3200 ppmv (wet) / 4050 ppmv (dry), suggest that, from a corrosion standpoint, the materials used in conventional subcritical and supercritical, air-fired boilers should also be suitable for oxy-combustion retrofits. Although the laboratory test results are encouraging, they are only the first step of a material evaluation process and it is recommended that follow-on corrosion tests be conducted in coal-fired boilers operating under oxy-combustion to provide longer term (one to two year) data. The test program details and data are presented herein.

Michael Gagliano; Andrew Seltzer; Hans Agarwal; Archie Robertson; Lun Wang

2012-01-31

377

Low emission U-fired boiler combustion system  

DOEpatents

At least one main combustion chamber contains at least one pulverized coal burner. Each pulverized coal burner is operatively arranged for minimizing NO.sub.X production and for maintaining a predetermined operating temperature to liquefy ash within the combustion chamber. The combustion chamber includes a slag drain for removing slag from the combustion chamber. A slag screen is positioned in a generally U-shaped furnace flow pattern. The slag screen is positioned between the combustion chamber and a radiant furnace. The radiant furnace includes a reburning zone for in-furnace No.sub.X reduction. The reburning zone extends between a reburning fuel injection source and at least one overfire air injection port for injecting air.

Ake, Terence (North Brookfield, MA); Beittel, Roderick (Worcester, MA); Lisauskas, Robert A. (Shrewsbury, MA); Reicker, Eric (Barre, MA)

2000-01-01

378

Engine combustion control at low loads via fuel reactivity stratification  

DOEpatents

A compression ignition (diesel) engine uses two or more fuel charges during a combustion cycle, with the fuel charges having two or more reactivities (e.g., different cetane numbers), in order to control the timing and duration of combustion. By appropriately choosing the reactivities of the charges, their relative amounts, and their timing, combustion can be tailored to achieve optimal power output (and thus fuel efficiency), at controlled temperatures (and thus controlled NOx), and with controlled equivalence ratios (and thus controlled soot). At low load and no load (idling) conditions, the aforementioned results are attained by restricting airflow to the combustion chamber during the intake stroke (as by throttling the incoming air at or prior to the combustion chamber's intake port) so that the cylinder air pressure is below ambient pressure at the start of the compression stroke.

Reitz, Rolf Deneys; Hanson, Reed M; Splitter, Derek A; Kokjohn, Sage L

2014-10-07

379

Integration of air separation membrane and coalescing filter for use on an inlet air system of an engine  

DOEpatents

An intake air separation system suitable for combustion air of an internal combustion engine. An air separation device of the system includes a plurality of fibers, each fiber having a tube with a permeation barrier layer on the outer surface thereof and a coalescing layer on the inner surface thereof, to restrict fluid droplets from contacting the permeation barrier layer.

Moncelle, Michael E. (Bloomington, IL)

2003-01-01

380

Method of regulating combustion in the combustion chambers of an internal combustion engine  

Microsoft Academic Search

A method is proposed for regulating the combustion of operating mixtures in the combustion chambers of internal combustion engines. The course of the light intensity of the light resulting from combustion in the combustion chamber is detected and evaluated over the course of combustion; reference control variables derived therefrom are formed for use by subsequently disposed closed-loop control devices of

R. Burkel; K. Eckert; H. Franke; E. Linder; H. Maurer; W. Moser; K. Muller; C. Peter; F. Rieger

1983-01-01

381

Air tight fuel burning stove  

SciTech Connect

A fuel burning stove is claimed for holding and burning fuel to heat the surrounding atmosphere in a room where the stove is employed. The stove includes a fire box which supports the fuel and where the combustion is sustained. An air inlet is provided to the fire box allowing the inflow of air for combustion with the fuel. The air is preheated upon entry into the fire box for mixture with volatiles formed by the burning fuel directed toward the entering air by a baffle means to effect a secondary combustion. In addition, a movable damper cooperates with the baffle to direct volatiles toward the incoming heated air when the damper is in the closed position and to provide a more direct path to the chimney when in the open position.

Nietupski, V.J.

1980-03-11

382

Wood stove with safety forced air system  

SciTech Connect

A high efficiency, air-tight wood stove has a firebox with front, side, rear, top and bottom walls, primary air introducing means for admitting combustion air into the firebox, air flow means adjacent the bottom of the firebox for directing a flow of air upwardly across at least one firebox wall, at least one supplemental air inlet for diverting a portion of the air from the air flow means into the firebox, fan means for forcing air through the air flow means and through the supplemental air inlet, the size of the primary air introducing means being chosen to automatically restrict the combustion in the firebox if the fan means stops to maintain the temperature of the stove and surroundings at safe levels.

Erickson, A.J.; Thulman, R.D.

1982-08-03

383

JANNAF 35th Combustion Subcommittee Meeting. Volume 1  

NASA Technical Reports Server (NTRS)

Volume 1, the first of two volumes is a compilation of 63 unclassified/unlimited distribution technical papers presented at the 35th meeting of the Joint Army-Navy-NASA-Air Force (JANNAF) Combustion Subcommittee (CS) held jointly with the 17th Propulsion Systems Hazards Subcommittee (PSHS) and Airbreathing Propulsion Subcommittee (APS). The meeting was held on 7-11 December 1998 at Raytheon Systems Company and the Marriott Hotel, Tucson, AZ. Topics covered include solid gun propellant processing, ignition and combustion, charge concepts, barrel erosion and flash, gun interior ballistics, kinetics and molecular modeling, ETC gun modeling, simulation and diagnostics, and liquid gun propellant combustion; solid rocket motor propellant combustion, combustion instability fundamentals, motor instability, and measurement techniques; and liquid and hybrid rocket combustion.

Fry, Ronald S. (Editor); Gannaway, Mary T. (Editor); Rognan, Melanie (Editor)

1998-01-01

384

JANNAF 36th Combustion Subcommittee Meeting. Volume 1  

NASA Technical Reports Server (NTRS)

Volume 1, the first of three volumes is a compilation of 47 unclassified/unlimited-distribution technical papers presented at the Joint Army-Navy-NASA-Air Force (JANNAF) 36th Combustion Subcommittee held jointly with the 24th Airbreathing Propulsion Subcommittee and 18th Propulsion Systems Hazards Subcommittee. The meeting was held on 18-21 October 1999 at NASA Kennedy Space Center and The DoubleTree Oceanfront Hotel, Cocoa Beach, Florida. Solid phase propellant combustion topics covered in this volume include cookoff phenomena in the pre- and post-ignition phases, solid rocket motor and gun propellant combustion, aluminized composite propellant combustion, combustion modeling and combustion instability and instability measurement techniques.

Fry, Ronald S. (Editor); Gannaway, Mary T. (Editor)

1999-01-01

385

Staged combustion of rice straw in a fluidized bed  

SciTech Connect

Staged combustion of rice straw has been investigated using an atmospheric bubbling fluidized bed combustor. The combustor has a 300 mm ID and a 3300 mm height. Secondary air was introduced in the freeboard at 1500 mm above the primary air distributor. Rice straw was fed as cylindrical pellets of a 12 mm diameter and 10-15 mm lengths. The obtained results indicate that staged combustion appears an effective technique to reduce NO{sub x} emissions, in particular, at higher operating temperatures. Typically, at 850 C bed temperature, NO{sub x} concentration is reduced by about 50% when 30% of fed air is introduced as secondary air. Staged operation has a slight, non-monotonic effect on SO{sub 2} emission. Combustion efficiency improves with increasing secondary air ratio reaching a maximum value that is mainly attributed to a reduction in fixed carbon loss. With further increase in secondary air ratio, combustion efficiency, however, decreases again since entrained fixed carbon and exhausted carbon monoxide tend to increase. The range of secondary air ratio, over which combustion efficiency improves, expands at higher operating temperatures. (author)

Okasha, F. [Department of Mechanical Engineering, Mansoura University (Egypt)

2007-10-15

386

History of staged combustion cycle development  

NASA Astrophysics Data System (ADS)

The search for ever greater delivered specific impulse led to an interest in very high chamber pressure operation, and with it, exploration of the staged combustion cycle as a means to extract the most energy possible from the chemical reactants. A major effort was supported by the Air Force with possible application to engines in the 1-2 million pound thrust class which used storable liquid propellants. These programs advanced the art by demonstrating the use of supercritical N2O4 as a coolant and introducing the photo etched platelet technique for manufacturing both injector and thrust chamber hardware. NASA initiated advanced engine design studies which identified the promise of high-pressure staged combustion and then accomplished subscale staged combustion testing at 2500 psia to demonstrate the feasibility of the combustion system. The Air Force also initiated efforts on high discharge pressure hydrogen pumps and on a high chamber pressure H2/O2 staged combustion engine concept which established the turbomachinery and cycle groundwork for the SSME.

Bumb, Anu; Hawk, Clark W.

1993-06-01

387

Dust Combustion Safety Issues for Fusion Applications  

SciTech Connect

This report summarizes the results of a safety research task to identify the safety issues and phenomenology of metallic dust fires and explosions that are postulated for fusion experiments. There are a variety of metal dusts that are created by plasma erosion and disruptions within the plasma chamber, as well as normal industrial dusts generated in the more conventional equipment in the balance of plant. For fusion, in-vessel dusts are generally mixtures of several elements; that is, the constituent elements in alloys and the variety of elements used for in-vessel materials. For example, in-vessel dust could be composed of beryllium from a first wall coating, tungsten from a divertor plate, copper from a plasma heating antenna or diagnostic, and perhaps some iron and chromium from the steel vessel wall or titanium and vanadium from the vessel wall. Each of these elements has its own unique combustion characteristics, and mixtures of elements must be evaluated for the mixture’s combustion properties. Issues of particle size, dust temperature, and presence of other combustible materials (i.e., deuterium and tritium) also affect combustion in air. Combustion in other gases has also been investigated to determine if there are safety concerns with “inert” atmospheres, such as nitrogen. Several coolants have also been reviewed to determine if coolant breach into the plasma chamber would enhance the combustion threat; for example, in-vessel steam from a water coolant breach will react with metal dust. The results of this review are presented here.

L. C. Cadwallader

2003-05-01

388

Characteristics of dual-combustion ramjet  

NASA Astrophysics Data System (ADS)

The authors discuss a possibility to use a diverging dual-combustion chamber as applied to high-supersonic boost ramjets operating at flight Mach numbers up to Mf = 8-10. Due to diverging, this chamber allows beginning the ramjet operation from flight Mach numbers Mf ini = 2-3. The diverging combustion chamber is characterized by a ratio of its exit cross-sectional area relative to the cross-sectional area of air-intake throat. This expansion area ratio is determined at Mf = Mf ini, but it should be the same at all flight Mach numbers Mf ? Mf ini, and depends on two factors: the location of a normal shock in the air-intake throat and the condition of reaching the critical velocity at the chamber exit. The dual-combustion chamber provides heat supply in its alone channel first to the subsonic flow and then, along with acceleration of the flying vehicle, to the supersonic flow, which is bound with a decrease in relative heating of working gas. Calculations of characteristics of an exemplified dual-combustion ramjet considered with a twodimensional air-intake were performed in the range of Mf = 3-7.

Gounko, Yu. P.; Shumskiy, V. V.

2014-08-01

389

Combustion modeling in internal combustion engines  

NASA Technical Reports Server (NTRS)

The fundamental assumptions of the Blizard and Keck combustion model for internal combustion engines are examined and a generalization of that model is derived. The most significant feature of the model is that it permits the occurrence of unburned hydrocarbons in the thermodynamic-kinetic modeling of exhaust gases. The general formulas are evaluated in two specific cases that are likely to be significant in the applications of the model.

Zeleznik, F. J.

1976-01-01

390

Real-time combustion controller  

DOEpatents

A method and system of regulating the air to fuel ratio supplied to a burner to maximize the combustion efficiency. Optical means are provided in close proximity to the burner for directing a beam of radiation from hot gases produced by the burner to a plurality of detectors. Detectors are provided for sensing the concentration of, inter alia, CO, CO.sub.2, and H.sub.2 O. The differences between the ratios of CO to CO.sub.2 and H.sub.2 O to CO are compared with a known control curve based on those ratios for air to fuel ratios ranging from 0.85 to 1.30. The fuel flow is adjusted until the difference between the ratios of CO to CO.sub.2 and H.sub.2 O to CO fall on a desired set point on the control curve.

Lindner, Jeffrey S. (Starkville, MS); Shepard, W. Steve (Starkville, MS); Etheridge, John A. (Starkville, MS); Jang, Ping-Rey (Starkville, MS); Gresham, Lawrence L. (Starkville, MS)

1997-01-01

391

Real-time combustion controller  

DOEpatents

A method and system are disclosed for regulating the air to fuel ratio supplied to a burner to maximize the combustion efficiency. Optical means are provided in close proximity to the burner for directing a beam of radiation from hot gases produced by the burner to a plurality of detectors. Detectors are provided for sensing the concentration of, inter alia, CO, CO{sub 2}, and H{sub 2}O. The differences between the ratios of CO to CO{sub 2} and H{sub 2}O to CO are compared with a known control curve based on those ratios for air to fuel ratios ranging from 0.85 to 1.30. The fuel flow is adjusted until the difference between the ratios of CO to CO{sub 2} and H{sub 2}O to CO fall on a desired set point on the control curve. 20 figs.

Lindner, J.S.; Shepard, W.S.; Etheridge, J.A.; Jang, P.R.; Gresham, L.L.

1997-02-04

392

Understanding Air: Air Pollution and Modeling Pollutants with LEGO® Bricks  

NSDL National Science Digital Library

In this lesson, students learn about the chemical reactions that release various pollutants into the atmosphere and what happens when pollutants in the air are exposed to sunlight. They model incomplete combustion using LEGO bricks, and explore the connection between air quality and environmental health.

WGBH Educational Foundation

2012-06-15

393

Air Pollution: History Air Pollution: Any atmospheric constituent present as a result of  

E-print Network

Air Pollution: History Air Pollution: Any atmospheric constituent present as a result, or materials. Before 1200 AD · Air pollution results from wood burning, tanning, decaying trash, smelting = industrial revolution ­ x100 increase in G.B. coal combustion between 1800-1900 estimated air pollution in G

Weber, Rodney

394

Identification and idle speed control of internal combustion engines  

Microsoft Academic Search

This paper presents an integrated approach for the identification and control of internal combustion engines in idle-speed conditions. The inputs of the nonlinear identification model are the position of the idle speed air actuation system and the spark advance, while its outputs are the pressure inside the air intake manifold and the crank shaft speed. The estimated model is then

G. De Nicolao; C. Rossi; R. Scattolini; M. Suffritti

1999-01-01

395

Exhaust gas recirculation control system for internal combustion engine  

Microsoft Academic Search

An exhaust gas recirculation control system for controlling the amount of exhaust gas subjected to recirculation to the air inlet depending on the amount of inlet air of an internal combustion engine is described. This system comprises a control valve disposed in an exhaust gas recirculation passage, for controlling the amount of exhaust gas recirculation, an orifice disposed in the

T. Ito; T. Nishimiya; S. Numakura; M. Okumura

1980-01-01

396

38th JANNAF Combustion Subcommittee Meeting. Volume 1  

NASA Technical Reports Server (NTRS)

This volume, the first of two volumes, is a collection of 55 unclassified/unlimited-distribution papers which were presented at the Joint Army-Navy-NASA-Air Force (JANNAF) 38th Combustion Subcommittee (CS), 26 th Airbreathing Propulsion Subcommittee (APS), 20th Propulsion Systems Hazards Subcommittee (PSHS), and 21 Modeling and Simulation Subcommittee. The meeting was held 8-12 April 2002 at the Bayside Inn at The Sandestin Golf & Beach Resort and Eglin Air Force Base, Destin, Florida. Topics cover five major technology areas including: 1) Combustion - Propellant Combustion, Ingredient Kinetics, Metal Combustion, Decomposition Processes and Material Characterization, Rocket Motor Combustion, and Liquid & Hybrid Combustion; 2) Liquid Rocket Engines - Low Cost Hydrocarbon Liquid Rocket Engines, Liquid Propulsion Turbines, Liquid Propulsion Pumps, and Staged Combustion Injector Technology; 3) Modeling & Simulation - Development of Multi- Disciplinary RBCC Modeling, Gun Modeling, and Computational Modeling for Liquid Propellant Combustion; 4) Guns Gun Propelling Charge Design, and ETC Gun Propulsion; and 5) Airbreathing - Scramjet an Ramjet- S&T Program Overviews.

Fry, Ronald S. (Editor); Eggleston, Debra S. (Editor); Gannaway, Mary T. (Editor)

2002-01-01

397

Air Pollution Control, Part I.  

ERIC Educational Resources Information Center

Authoritative reviews in seven areas of current importance in air pollution control are supplied in this volume, the first of a two-part set. Titles contained in this book are: "Dispersion of Pollutants Emitted into the Atmosphere,""The Formation and Control of Oxides of Nitrogen in Air Pollution,""The Control of Sulfur Emissions from Combustion

Strauss, Werner, Ed.

398

Coal combustion products  

USGS Publications Warehouse

Coal-burning powerplants, which supply more than half of U.S. electricity, also generate coal combustion products, which can be both a resource and a disposal problem. The U.S. Geological Survey collaborates with the American Coal Ash Association in preparing its annual report on coal combustion products. This Fact Sheet answers questions about present and potential uses of coal combustion products.

Kalyoncu, R.S.; Olson, D.W.

2001-01-01

399

Emission Characteristics of NOx and Unburned Carbon in Fly Ash of Sub-bituminous Coal Combustion  

NASA Astrophysics Data System (ADS)

Sub-bituminous coal is considered to be one substitute fuel for bituminous coal. Since sub-bituminous coal contains more than 20% moisture, there are some problems with its utilization, such as a decrease in combustibility, high NOx emission and so on. This report describes the emission characteristics of NOx and unburned carbon in fly ash of sub-bituminous coal combustion through the use of a pulverized coal combustion test furnace. On the sub-bituminous coal combustion, ignition at the burner exit worsened and the combustion flame became diffused. Then, both NOx emission and the unburned carbon concentration in fly ash became high. In order to keep stable combustion and to form an effective NOx reduction flame, the swirl vane angle of secondary air was reduced and the Air/Coal ratio was lowered. As a result, the combustion flame became moderate, and both NOx emission and unburned carbon concentration in fly ash could be reduced.

Ikeda, Michitaka; Kozai, Yukitoshi; Makino, Hisao

400

Circulating-air heating stove with exit air heat extractor  

SciTech Connect

A circulating air wood burning heating stove/fireplace combination has a combustion chamber for burning fuel. The combustion chamber is in the form of a shell defined by inner walls of the stove and a rearwardly disposed air outlet manifold. Spaced outer auxiliary back and top walls and the corresponding shell walls form therebetween air passages through which ambient air is recirculated into the room over the manifold. The manifold is provided with a plurality of spaced heat conductive metal strips disposed about its periphery. An air inlet is provided at the bottom of the back air passage and an electric fan or blower is attached to the inlet to force air into the back air passage. This air then passes upwardly in the space between the back walls , over and under the air outlet manifold and past the heat conductive metal strips, through the air passage formed between the top walls which extend across the top of the fire chamber and then exits through an upper grill work provided in the front face of the stove into the space to be heated. Additional heat conductive metal strips may be provided in the top air passage connected directly to the top wall of the fire chamber to extract heat thereof and improve the heat exchange prior to discharge of the heated air into the space to be heated. A baffle is provided in the fire chamber to create turbulence and to provide a torturous path for the combustion products within the fire chamber so as to prevent the combustion gases or products from escaping directly through the inlet openings of the manifold to the flue.

Homolik, M.W.

1982-11-30

401

Tripropellant combustion process  

NASA Technical Reports Server (NTRS)

The addition of small amounts of hydrogen to the combustion of LOX/hydrocarbon propellants in large rocket booster engines has the potential to enhance the system stability. Programs being conducted to evaluate the effects of hydrogen on the combustion of LOX/hydrocarbon propellants at supercritical pressures are described. Combustion instability has been a problem during the development of large hydrocarbon fueled rocket engines. At the higher combustion chamber pressures expected for the next generation of booster engines, the effect of unstable combustion could be even more destructive. The tripropellant engine cycle takes advantage of the superior cooling characteristics of hydrogen to cool the combustion chamber and a small amount of the hydrogen coolant can be used in the combustion process to enhance the system stability. Three aspects of work that will be accomplished to evaluate tripropellant combustion are described. The first is laboratory demonstration of the benefits through the evaluation of drop size, ignition delay and burning rate. The second is analytical modeling of the combustion process using the empirical relationship determined in the laboratory. The third is a subscale demonstration in which the system stability will be evaluated. The approach for each aspect is described and the analytical models that will be used are presented.

Kmiec, T. D.; Carroll, R. G.

1988-01-01

402

Combustion under microgravity conditions  

SciTech Connect

Reduced gravity combustion experiments are frequently required to provide the information necessary for comprehensive understanding of combustion phenomena at normal gravitational conditions. Previous papers have dealt in detail with a broad range of combustion science experiments which require reduced gravity experimentation. This paper enlarges on these previous studies. Reduced gravity experiments are shown to be needed for comprehensive understanding of kinetic and thermokinetic oscillatory flame processes, the radiative ignition of solids, high pressure flame propagation and extinction phenomena, as well as a number of other combustion science areas of vital interest.

Berlad, A.L.

1982-01-01

403

Symposium (International) on Combustion, 22nd, University of Washington, Seattle, Aug. 14-19, 1988, Proceedings  

SciTech Connect

Papers on combustion are presented, including papers on coal combustion, combustion-generated particulates, engine combustion, turbulent combustion, reaction kinetics, combustion-generated NO(x) and SO(x), fires, fire characterization, laminar flames, ignition and extinction, detonations and explosions, dust combustion, propellants, combustion diagnostics, and multiphase combustion. Specific topics include soot formation in diffusion flames of fuel/oxygen mixtures, sooting limits of aerodynamically-strained diffusion flames, premixed combustion in a vortex, the structure of a laminar nonpremixed flame in an unsteady vortical flow, and a model gas turbine combustor with wall jets and optical access for turbulent mixing, fuel effects, and spray studies. Additional topics include the role of the recirculation vortex in improving fuel-air mixing within swirling flames, fractal geometry applications in turbulent combustion data analysis, a simulation with a cellular automaton for turbulent combustion modeling, turbulent combustion in nonpremixed flames, the structure of premixed turbulent flames, lifted turbulent jet flames, chemical kinetic modeling and sensitivity analyses for boron-assisted hydrocarbon combustion, the driving force of PAH production, and the near-limit flame spread over a thin solid fuel in microgravity.

Not Available

1989-01-01

404

Effects of inlet distortion on gas turbine combustion chamber exit temperature profiles  

NASA Astrophysics Data System (ADS)

Damage to a nozzle guide vane or blade, caused by non-uniform temperature distributions at the combustion chamber exit, is deleterious to turbine performance and can lead to expensive and time consuming overhaul and repair. A test rig was designed and constructed for the Allison 250-C20B combustion chamber to investigate the effects of inlet air distortion on the combustion chamber's exit temperature fields. The rig made use of the engine's diffuser tubes, combustion case, combustion liner, and first stage nozzle guide vane shield. Rig operating conditions simulated engine cruise conditions, matching the quasi-non-dimensional Mach number, equivalence ratio and Sauter mean diameter. The combustion chamber was tested with an even distribution of inlet air and a 4% difference in airflow at either side. An even distribution of inlet air to the combustion chamber did not create a uniform temperature profile and varying the inlet distribution of air exacerbated the profile's non-uniformity. The design of the combustion liner promoted the formation of an oval-shaped toroidal vortex inside the chamber, creating localized hot and cool sections separated by 90° that appeared in the exhaust. Uneven inlet air distributions skewed the oval vortex, increasing the temperature of the hot section nearest the side with the most mass flow rate and decreasing the temperature of the hot section on the opposite side. Keywords: Allison 250, Combustion, Dual-Entry, Exit Temperature Profile, Gas Turbine, Pattern Factor, Reverse Flow.

Maqsood, Omar Shahzada

405

TOXIC SUBSTANCES FROM COAL COMBUSTION  

SciTech Connect

The Clean Air Act Amendments of 1990 identify a number of hazardous air pollutants (HAPs) as candidates for regulation. Should regulations be imposed on HAP emissions from coal-fired power plants, a sound understanding of the fundamental principles controlling the formation and partitioning of toxic species during coal combustion will be needed. With support from the Federal Energy Technology Center (FETC), the Electric Power Research Institute, the Lignite Research Council, and VTT (Finland), Physical Sciences Inc. (PSI) has teamed with researchers from USGS, MIT, the University of Arizona (UA), the University of Kentucky (UK), the University of Connecticut (UC), the University of Utah (UU) and the University of North Dakota Energy and Environmental Research Center (EERC) to develop a broadly applicable emissions model useful to regulators and utility planners. The new Toxics Partitioning Engineering Model (ToPEM) will be applicable to all combustion conditions including new fuels and coal blends, low-NO combustion systems, and new power generation x plants. Development of ToPEM will be based on PSI's existing Engineering Model for Ash Formation (EMAF). This report covers the reporting period from 1 July 1998 through 30 September 1998. During this period distribution of all three Phase II coals was completed. Standard analyses for the whole coal samples were also completed. Mössbauer analysis of all project coals and fractions received to date has been completed in order to obtain details of the iron mineralogy. The analyses of arsenic XAFS data for two of the project coals and for some high arsenic coals have been completed. Duplicate splits of the Ohio 5,6,7 and North Dakota lignite samples were taken through all four steps of the selective leaching procedure. Leaching analysis of the Wyodak coal has recently commenced. Preparation of polished coal/epoxy pellets for probe/SEM studies is underway. Some exploratory mercury LIII XAFS work was carried out during August at the Advanced Photon Source (APS), the new synchrotron facility at Argonne National Laboratory, Chicago, IL. Further analysis of small-scale combustion experiments conducted at PSI in Phase I was completed this quarter. The results of these experiments for the first time suggest almost complete vaporization of certain trace elements (Se, Zn) from coal combustion in the flame zone, in accordance with theoretical equilibrium predictions. Other elements (As, Sb, Cr) appeared considerably less volatile and may react with constituents in the bulk ash at combustion temperatures. The combustion section of the University of Arizona's Downflow Combustor was completely rebuilt. The University of Utah worked on setting up EPA Method 26A to give the capability to measure chlorine in flue gas. The chlorine kinetic calculations performed as part of the Phase I program were found to have an error in the initial conditions. Therefore, the calculations were re-done this quarter with the correct starting conditions. Development of a quasi-empirical emissions model based on reported emissions of particulate matter from field measurements was continued this quarter. As a first step in developing the ToPEM, we developed a sub-model that calculates the evaporation of major elements (Na, K, Fe, Si, Al, Ca and Mg) from both inherent and extraneous minerals of coal. During this quarter, this sub-model was included into EMAF, which formed the ToPEM. Experimental data from the Phase I program were used to test and modify the sub-model and the ToPEM.

A KOLKER; AF SAROFIM; CL SENIOR; FE HUGGINS; GP HUFFMAN; I OLMEZ; J LIGHTY; JOL WENDT; JOSEPH J HELBLE; MR AMES; N YAP; R FINKELMAN; T PANAGIOTOU; W SEAMES

1998-12-08

406

Characteristics of the thermal regime of circular tube combustion chambers with combined wall cooling  

NASA Astrophysics Data System (ADS)

The thermal characteristics of circular tube gas turbine engine combustion chambers cooled by external blowing and the creation of an internal air-enclosed sheet are investigated. Combustion chamber wall temperatures were measured as a function of air flow parameters and fuel type (kerosene or natural gas) for two flame tube configurations. It is found that kerosene combustion leads to a higher wall temperature than natural gas, while increased air temperature increases wall temperature and air pressure is observed to have no effect in the range studied. It is also observed that the gas delivery scheme has little influence on wall temperature, while the influence of the air excess coefficient and the entrance velocity are shown to depend on flame tube air intake geometry. Results indicate that local combustion chamber wall temperatures may be lowered by creating additional flame tube openings or by drilling existing ones.

Didenko, V. I.; Khristich, V. A.; Liubchik, G. N.; Shevchenko, A. M.

1980-03-01

407

Low Temperature Combustion Demonstrator for High Efficiency Clean Combustion  

SciTech Connect

The project which extended from November 2005 to May of 2010 demonstrated the application of Low Temperature Combustion (LTC) with engine out NOx levels of 0.2 g/bhp-hr throughout the program target load of 12.6bar BMEP. The project showed that the range of loads could be extended to 16.5bar BMEP, therefore matching the reference lug line of the base 2007 MY Navistar 6.4L V8 engine. Results showed that the application of LTC provided a dramatic improvement over engine out emissions when compared to the base engine. Furthermore LTC improved thermal efficiency by over 5% from the base production engine when using the steady state 13 mode composite test as a benchmark. The key enablers included improvements in the air, fuel injection, and cooling systems made in Phases I and II. The outcome was the product of a careful integration of each component under an intelligent control system. The engine hardware provided the conditions to support LTC and the controller provided the necessary robustness for a stable combustion. Phase III provided a detailed account on the injection strategy used to meet the high load requirements. During this phase, the control strategy was implemented in a production automotive grade ECU to perform cycle-by-cycle combustion feedback on each of the engine cylinders. The control interacted on a cycle base with the injection system and with the Turbo-EGR systems according to their respective time constants. The result was a unique system that could, first, help optimize the combustion system and maintain high efficiency, and secondly, extend the steady state results to the transient mode of operation. The engine was upgraded in Phase IV with a Variable Valve Actuation system and a hybrid EGR loop. The impact of the more versatile EGR loop did not provide significant advantages, however the application of VVA proved to be an enabler to further extend the operation of LTC and gain considerable benefits in fuel economy and soot reduction. Finally, the transient demonstration was performed in Phase IV. The project demonstrated the achievement of meeting US10 emissions without NOx aftertreatment. The successful execution of the project has served to highlight the effectiveness of closely matched combustion predictive tools to engine testing. It has further served to highlight the importance of key technologies and future areas of research and development. In this regard, recommendations are made towards further improvements in the areas of engine hardware, fuel injection systems, controls and fuels.

Ojeda, William de

2010-07-31

408

High Efficiency, Clean Combustion  

SciTech Connect

Energy use in trucks has been increasing at a faster rate than that of automobiles within the U.S. transportation sector. According to the Energy Information Administration (EIA) Annual Energy Outlook (AEO), a 23% increase in fuel consumption for the U.S. heavy duty truck segment is expected between 2009 to 2020. The heavy duty vehicle oil consumption is projected to grow between 2009 and 2050 while light duty vehicle (LDV) fuel consumption will eventually experience a decrease. By 2050, the oil consumption rate by LDVs is anticipated to decrease below 2009 levels due to CAFE standards and biofuel use. In contrast, the heavy duty oil consumption rate is anticipated to double. The increasing trend in oil consumption for heavy trucks is linked to the vitality, security, and growth of the U.S. economy. An essential part of a stable and vibrant U.S. economy is a productive U.S. trucking industry. Studies have shown that the U.S. gross domestic product (GDP) is strongly correlated to freight transport. Over 90% of all U.S. freight tonnage is transported by diesel power and over 75% is transported by trucks. Given the vital role that the trucking industry plays in the economy, improving the efficiency of the transportation of goods was a central focus of the Cummins High Efficient Clean Combustion (HECC) program. In a commercial vehicle, the diesel engine remains the largest source of fuel efficiency loss, but remains the greatest opportunity for fuel efficiency improvements. In addition to reducing oil consumption and the dependency on foreign oil, this project will mitigate the impact on the environment by meeting US EPA 2010 emissions regulations. Innovation is a key element in sustaining a U.S. trucking industry that is competitive in global markets. Unlike passenger vehicles, the trucking industry cannot simply downsize the vehicle and still transport the freight with improved efficiency. The truck manufacturing and supporting industries are faced with numerous challenges to reduce oil consumption and greenhouse gases, meet stringent emissions regulations, provide customer value, and improve safety. The HECC program successfully reduced engine fuel consumption and greenhouse gases while providing greater customer valve. The US EPA 2010 emissions standard poses a significant challenge for developing clean diesel powertrains that meet the DoE Vehicle Technologies Multi-Year Program Plan (MYPP) for fuel efficiency improvement while remaining affordable. Along with exhaust emissions, an emphasis on heavy duty vehicle fuel efficiency is being driven by increased energy costs as well as the potential regulation of greenhouse gases. An important element of the success of meeting emissions while significantly improving efficiency is leveraging Cummins component technologies such as fuel injection equipment, aftertreatment, turbomahcinery, electronic controls, and combustion systems. Innovation in component technology coupled with system integration is enabling Cummins to move forward with the development of high efficiency clean diesel products with a long term goal of reaching a 55% peak brake thermal efficiency for the engine plus aftertreatment system. The first step in developing high efficiency clean products has been supported by the DoE co-sponsored HECC program. The objectives of the HECC program are: (1) To design and develop advanced diesel engine architectures capable of achieving US EPA 2010 emission regulations while improving the brake thermal efficiency by 10% compared to the baseline (a state of the art 2007 production diesel engine). (2) To design and develop components and subsystems (fuel systems, air handling, controls, etc) to enable construction and development of multi-cylinder engines. (3) To perform an assessment of the commercial viability of the newly developed engine technology. (4) To specify fuel properties conducive to improvements in emissions, reliability, and fuel efficiency for engines using high-efficiency clean combustion (HECC) technologies. To demonstrate the technology is compatible with B2

Donald Stanton

2010-03-31

409

Properties of air and combustion products of fuels with air  

NASA Technical Reports Server (NTRS)

Thermodynamic and transport properties include ratio of specific heats, molecular weight, viscosity, heat capacity, thermal conductivity, and Prandtl number. Properties are calculated from 300 to 2500 degrees K and for pressures of three and ten atmospheres.

Lewandowski, K.; Poferl, D. J.; Svevla, R.

1969-01-01

410

A review on the technical adaptations for internal combustion engines to operate with gas\\/hydrogen mixtures  

Microsoft Academic Search

The use of the hydrogen as fuel in the internal combustion engine represents an alternative use to replace the hydrocarbons fuels, which produce during the combustion reaction a pollutes gases. The hydrogen is the most abundant material in the universe and during its combustion with air only produces nitrous oxides (NOx) gas, which can collect and avoid their emission to

M. A. Escalante Soberanis; A. M. Fernandez

2010-01-01

411

Multi-Zone DI Diesel Spray Combustion Model for Cycle Simulation Studies of Engine Performance and Emissions  

Microsoft Academic Search

A quasi -dimensional, multi-zone, direct injection (DI) diesel combustion model has been developed and implemented in a full cycle simulation of a turbocharged engine. The combustion model accounts for transient fuel spray evolution, fuel-air mixing, ignition, combustion and NO and soot pollutant formation. In the model, the fuel spray is divided into a number of zones, which are treated as

Dohoy Jung; Dennis N. Assanis

2001-01-01

412

THE GENOTOXICITY OF AMBIENT OUTDOOR AIR, A REVIEW: SALMONELLA MUTAGENICITY  

EPA Science Inventory

The genotoxicity of ambient outdoor air, a review: Salmonella mutagenicity Abstract Mutagens in urban air pollution come from anthropogenic sources (especially combustion sources) and are products of airborne chemical reactions. Bacterial mutation tests have been used ...

413

Fifteenth combustion research conference  

SciTech Connect

The BES research efforts cover chemical reaction theory, experimental dynamics and spectroscopy, thermodynamics of combustion intermediates, chemical kinetics, reaction mechanisms, combustion diagnostics, and fluid dynamics and chemically reacting flows. 98 papers and abstracts are included. Separate abstracts were prepared for the papers.

NONE

1993-06-01

414

Internal combustion engine  

Microsoft Academic Search

This patent describes an internal combustion engine of the two-cycle type. It comprises a cylinder, a piston slidable within the cylinder, a cylinder head to seal the cylinder at the top, thereby defining a combustion chamber, a crankshaft means to provide reciprocating motion to the piston, a lubricating means to lubricate the crankshaft, a sealing means around the bottom of

Van Blaricom

1992-01-01

415

Coal Combustion Science  

SciTech Connect

The objective of this activity is to support the Office of Fossil Energy in executing research on coal combustion science. This activity consists of basic research on coal combustion that supports both the Pittsburgh Energy Technology Center Direct Utilization Advanced Research and Technology Development Program, and the International Energy Agency Coal Combustion Science Project. Specific tasks for this activity include: (1) coal devolatilization - the objective of this risk is to characterize the physical and chemical processes that constitute the early devolatilization phase of coal combustion as a function of coal type, heating rate, particle size and temperature, and gas phase temperature and oxidizer concentration; (2) coal char combustion -the objective of this task is to characterize the physical and chemical processes involved during coal char combustion as a function of coal type, particle size and temperature, and gas phase temperature and oxygen concentration; (3) fate of mineral matter during coal combustion - the objective of this task is to establish a quantitative understanding of the mechanisms and rates of transformation, fragmentation, and deposition of mineral matter in coal combustion environments as a function of coal type, particle size and temperature, the initial forms and distribution of mineral species in the unreacted coal, and the local gas temperature and composition.

Hardesty, D.R. (ed.); Fletcher, T.H.; Hurt, R.H.; Baxter, L.L. (Sandia National Labs., Livermore, CA (United States))

1991-08-01

416

Emissions modeling of fluidised bed co-combustion of poultry litter and peat.  

PubMed

Gaseous emissions from the fluidised bed co-combustion of 50% w/w chicken litter and peat were monitored and recorded. Emission data were used to create a dispersion model for a proposed site on a poultry farm in Ireland. Variables within the combustion unit influenced both combustion and emission levels of pollutants such as SO(2) and NO(x), CO. Concentrations of atmospheric pollutants decreased with use of the correct ratio between fluidising and secondary air. Dispersion modelling of combustion at a proposed poultry unit predicted that ground level concentrations for the set of emissions data would be below the limits and guidelines set by air quality standards. PMID:12507869

Henihan, A M; Leahy, M J; Leahy, J J; Cummins, E; Kelleher, B P

2003-05-01

417

Gu, X., Haq, M. Z., Lawes, M. and Woolley, R. (2000), "Laminar Burning Velocity and Markstein Lengths of Methane-Air Mixtures", Combustion and Flame, 121:41-58  

E-print Network

by retaining a fraction of the combustion products from a previous experiment. Figure 1 Bomb schematic automatic detection and cell counting ·Use kinetic simulation to review the form of the correlation ·Multi ·Schlieren will also be used to detect cellularity ·Link to sudden Su increase due to larger surface area

418

Secondary combustion system for wood burning stove  

SciTech Connect

This patent describes an improved secondary combustion system for combusting the exhaust gases exiting from a fire box in a wood burning stove comprising: an insulated conduit defining an exhaust passageway leading from an intake opening to an exit opening; screen means interposed across the exhaust passageway in the vicinity of the intake opening to impart a rapid acceleration to a gas stream entering the exhaust passageway; rotation means to impart a rotation to the gas stream in a first portion of the exhaust passageway; counter-rotation means to impart a counter-rotation to the gas stream in a second portion of the exhaust passageway; deceleration means to decelerate the gas stream in the second portion of the exhaust passageway; and secondary air means to inject a source of secondary air into the exhaust passageway.

von Conta, P.E.W.

1986-12-16

419

Turbulence modeling in supersonic combusting flows  

NASA Technical Reports Server (NTRS)

To support the National Aerospace Plane project, the RPLUS3D CFD code has been developed at NASA Lewis. The code has the ability to solve three-dimensional flowfields with finite rate combustion of hydrogen and air. The combustion processes of the hydrogen-air system are simulated by an 18-reaction path, 8-species chemical kinetic mechanism. The code uses a Lower-Upper (LU) decomposition numerical algorithm as its basis, making it a very efficient and robust code. Except for the Jacobian matrix for the implicit chemistry source terms, there is no inversion of a matrix even though it uses a fully implicit numerical algorithm. A k-epsilon (two equation) turbulence model is incorporated into the RPLUS3D code.

Chitsomboon, Tawit

1991-01-01

420

Explosively Driven Combustion of Shock-Dispersed Fuels  

Microsoft Academic Search

The paper presents small-scale experiments with 1-g charges that explore the topic of post-detonation energy release due to the combustion of explosively dispersed fuels in the ambient air. To this end we have designed a new prototype small-scale charge, called Shock-Dispersed Fuel (SDF) charge. It consists of a lightweight, small paper cylinder filled with about one gram of a combustible

P. Neuwald

2006-01-01

421

Compression ratio effect on methane HCCI combustion  

Microsoft Academic Search

The authors have used the HCT (hydrodynamics, chemistry, and transport) chemical kinetics code to simulate HCCI (homogeneous charge compression ignition) combustion of methane-air mixtures. HCT is applied to explore the ignition timing, burn duration, NO{sub X}production, gross indicated efficiency and gross IMEP of a supercharged engine (3 atm. intake pressure) with 14:1, 16:1 and 18:1 compression ratios at 1200 rpm.

S. M. Aceves; J. R. Smith; C. K. Westbrook; W. J. Pitz

1999-01-01

422

Compression ratio effect on methane HCCI combustion  

Microsoft Academic Search

We have used the HCT (Hydrodynamics, Chemistry and Transport) chemical kinetics code to simulate HCCI (homogeneous charge compression ignition) combustion of methane-air mixtures. HCT is applied to explore the ignition timing, bum duration, NOx<\\/sub> production, gross indicated efficiency and gross IMEP of a supercharged engine (3 atm. Intake pressure) with 14:1, 16:l and 18:1 compression ratios at 1200 rpm. HCT

S. M. Aceves; W. Pitz; J. R. Smith; C. Westbrook

1998-01-01

423

Combustion control system for internal combustion engines  

Microsoft Academic Search

This patent describes a modified spark plug for internal combustion engines comprising: a base made of an electrically conductive material and adapted to be installed in the engine; an insulator disposed within the base and having a precombustion chamber formed therein; a central electrode passing through the insulator, extending into the precombustion chamber and defining a passageway in communication with

1988-01-01

424

Power generating and air conditioning system utilizing waste heat  

Microsoft Academic Search

A power generating and air conditioning system is presented which comprises an internal combustion engine, a vapor engine, and a refrigerant cooled air conditioning system wherein the vapor engine is driven by the expansion gas of refrigerant, the waste heat of the internal combustion engine is exchanged through a heat exchanger with the refrigerant, such as freon, and the pressure

1978-01-01

425

Structure of divided combustion chamber for internal combustion engine  

Microsoft Academic Search

This patent describes a structure defining a divided combustion chamber of an internal combustion engine, comprising an upper ceramic member, and a lower ceramic member having a transfer passage which communicates with a main combustion chamber of the engine. The upper and lower ceramic members meet with each other at an interface to form divided combustion chamber such that it

Y. Ogawa; T. Ogasawara; S. Hanzawa

1987-01-01

426

Assessment of RANS-Based Turbulent Combustion Models for Prediction of Emissions from Lean Premixed Combustion of Methane  

Microsoft Academic Search

Reynolds-Averaged Navier-Stokes (RANS) simulations of Lean Premixed Combustion (LPC) of methane–air in a bluff-body stabilized combustor were performed with several widely used turbulent combustion methodologies in order to assess their prediction capabilities. The methods employed are the Eddy Dissipation Concept (EDC), the Composition Probability Density Function (CPDF) and the Joint Velocity–Frequency-Composition PDF (VFCPDF) models. Where needed, two different models were

J. R. Nanduri; D. R. Parsons; S. L. Yilmaz; I. B. Celik; P. A. Strakey

2010-01-01

427

Reproductive adaptation in Drosophila exposed to oxygen-enriched atmospheres  

NASA Technical Reports Server (NTRS)

Ten successive generations of a Drosophila melanogaster population were exposed to an atmospheric mix of 50% oxygen/50% nitrogen at standard pressure. This atmospheric mix has been shown to be toxic to this species and causes significantly shortened life span. By the fifth generation, survivorship and life span for the first 25-30 days were identical to control populations and total life span was shorter by only a few days. Egg-laying rates were stable in the experimental populations but below those of the controls. Hatching success was identical between experimental and control populations. Even though the egg-laying rates were lower in 50% oxygen, it was concluded that the population had adapted and could maintain a stable population in these conditions. The near-normal life spans, normal hatching rates, and overall population stability, exhibited following five generations of adaptation, were considered sufficient to allow continued reproduction in spite of a reduced egg-laying rate.

Kloek, G.; Winkle, L.

1979-01-01

428

Effects of Air Pollution Control on Climate  

E-print Network

Urban air pollution and climate are closely connected due to shared generating processes (e.g., combustion) for emissions of the driving gases and aerosols. They are also connected because the atmospheric lifecycles of ...

Prinn, Ronald G.

429

Solid fuel combustion system for gas turbine engine  

DOEpatents

A solid fuel, pressurized fluidized bed combustion system for a gas turbine engine includes a carbonizer outside of the engine for gasifying coal to a low Btu fuel gas in a first fraction of compressor discharge, a pressurized fluidized bed outside of the engine for combusting the char residue from the carbonizer in a second fraction of compressor discharge to produce low temperature vitiated air, and a fuel-rich, fuel-lean staged topping combustor inside the engine in a compressed air plenum thereof. Diversion of less than 100% of compressor discharge outside the engine minimizes the expense of fabricating and maintaining conduits for transferring high pressure and high temperature gas and incorporation of the topping combustor in the compressed air plenum of the engine minimizes the expense of modifying otherwise conventional gas turbine engines for solid fuel, pressurized fluidized bed combustion.

Wilkes, Colin (Lebanon, IN); Mongia, Hukam C. (Carmel, IN)

1993-01-01

430

Investigation of shock-induced combustion past blunt projectiles  

NASA Technical Reports Server (NTRS)

A numerical study is conducted to simulate shock-induced combustion in premixed hydrogen-air mixtures at various free-stream conditions and parameters. Two-dimensional axisymmetric, reacting viscous flow over blunt projectiles is computed to study shock-induced combustion at Mach 5.11 and Mach 6.46 in hydrogen-air mixture. A seven-species, seven reactions finite rate hydrogen-air chemical reaction mechanism is used combined with a finite-difference, shock-fitting method to solve the complete set of Navier-Stokes and species conservation equations. The study has allowed an improved understanding of the physics of shock-induced combustion over blunt projectiles and the numerical results can now be explained more readily with one-dimensional wave-interaction model.

Ahuja, J. K.; Tiwari, S. N.

1996-01-01

431

Sandia Combustion Research: Technical review  

SciTech Connect

This report contains reports from research programs conducted at the Sandia Combustion Research Facility. Research is presented under the following topics: laser based diagnostics; combustion chemistry; reacting flow; combustion in engines and commercial burners; coal combustion; and industrial processing. Individual projects were processed separately for entry onto the DOE databases.

NONE

1995-07-01

432

Winged reentrant electromagnetic combustion chamber  

Microsoft Academic Search

An internal combustion engine combustion chamber suitable for electromagnetic stimulation of combustion which has been improved by the addition of combustion chamber periphery extensions (wings) filled with dielectric material. The wing dimensions and filler dielectric material are chosen to allow for specification of the chamber EM resonant frequency, preferably at a frequency in the UHF range (where low cost DC

M. A. V

1985-01-01

433

Particulate emissions from residential wood combustion: Final report: Norteast regional Biomass Program  

SciTech Connect

The objective of this study was to provide a resource document for the Northeastern states when pursuing the analysis of localized problems resulting from residential wood combustion. Specific tasks performed include assigning emission rates for total suspended particulates (TSP) and benzo(a)pyrene (BaP) from wood burning stoves, estimating the impact on ambient air quality from residential wood combustion and elucidating the policy options available to Northeastern states in their effort to limit any detrimental effects resulting from residential wood combustion. Ancillary tasks included providing a comprehensive review on the relevant health effects, indoor air pollution and toxic air pollutant studies. 77 refs., 11 figs., 25 tabs.

Not Available

1987-01-01

434

Pulsed atmospheric fluidized bed combustion  

SciTech Connect

The design of the Pulsed Atmospheric Fluidized Bed Combustor (PAFBC) as described in the Quarterly Report for the period April--June, 1992 was reviewed and minor modifications were included. The most important change made was in the coal/limestone preparation and feed system. Instead of procuring pre-sized coal for testing of the PAFBC, it was decided that the installation of a milling system would permit greater flexibility in the testing with respect to size distributions and combustion characteristics in the pulse combustor and the fluid bed. Particle size separation for pulse combustor and fluid bed will be performed by an air classifier. The modified process flow diagram for the coal/limestone handling system is presented in Figure 1. The modified process flow diagrams of the fluidized bed/steam cycle and ash handling systems are presented in Figures 2 and 3, respectively.

Not Available

1992-10-01

435

Studies in premixed combustion  

SciTech Connect

This report discusses the following topics on premixed combustion: theory of turbulent flame propagation; pattern formation in premixed flames and related problems; and pattern formation in extended systems. (LSP)

Sivashinsky, G.I.

1992-01-01

436

Ignition and combustion: Low compression ratio, high output diesel  

NASA Technical Reports Server (NTRS)

The feasibility of converting a spark ignition aircraft engine GTSI0-520 to compression ignition without increasing the peak combustion pressure of 1100 lbs/sq.in. was determined. The final contemplated utilized intake air heating at idle and light load and a compression ratio of about 10:1 with a small amount of fumigation (the addition of about 15% fuel into the combustion air before the cylinder). The engine used was a modification of a Continental-Teledyne gasoline engine cylinder from the GTSI0-520 supercharged aircraft engine.

1981-01-01

437

Combustion in fluidized beds  

Microsoft Academic Search

Circulating fluidized-bed (CFB) combustion systems have become popular since the late 1970s, and, given the current level of activity in the area,it is clear that this technology has a stable future in the boiler market. For standard coal combustion applications, competition is fierce with mature pulverized-fuel-based (PF) technology set to maintain a strong profile. CFB systems, however, can be more

F. J. Dry; R. D. La Nauze

1990-01-01

438

High-cycle fatigue design evolution and experience of free-standing combustion turbine blades  

Microsoft Academic Search

This paper presents the evolution of the combustion turbine blade high cycle fatigue design criteria for free-standing blades. It also presents the analysis and corrective actions taken to resolve several unique combustion turbine blade fatigue problems, all encountered over a 35-year period. Included are high-cycle fatigue problems due to cooling air leakage, seal pin friction, and combustion temperature maldistribution, as

A. J. Scalzo

1992-01-01

439

Simulation of the Combustion of Thin Iron Rods in Oxygen in the Adiabatic Approximation  

NASA Astrophysics Data System (ADS)

A mathematical model of the combustion of a thin iron rod in the atmosphere of oxygen with no forced air flow around it has been constructed. This model includes an adjustment parameter that relates the rate of combustion of the rod with its diameter and the content of oxygen. The problem on the combustion of a thin iron rod in oxygen was solved analytically in the adiabatic approximation. The results of calculations were compared with the corresponding experimental data.

Shabunya, S. I.; Martynenko, V. V.; Ignatenko, V. I.; Rostaing, J.-Ch.

2014-11-01

440

3D calculations of reacting flows within aircraft engine combustion chambers  

NASA Astrophysics Data System (ADS)

Some three-dimensional calculations have been worked out in the case of an aircraft engine combustion chamber containing one swirling fuel-air injector and four primary holes. The influence of the grid size and of some parameters of the combustion and turbulence models has been investigated. The combustion efficiency is relatively unsensitive to the grid size unlike the maximum wall temperature and depends slightly on the treatment of the k-epsilon equations near the wall.

Pit, F.; Tichtinsky, H.; Dupoirieux, F.

441

Co-combustion of pellets from Soma lignite and waste dusts of furniture works  

SciTech Connect

In this work, volatiles and char combustion behaviors of the fuel pellets prepared from a low quality lignite and the dusts of furniture works and their various blends were investigated in an experimental fixed bed combustion system through which air flowed by natural convection. Combustion data obtained for varied bed temperatures, mass of pellets, and blend compositions has showed that ignition times of the pellets decreased and volatiles combustion rates tended to increase with the burning temperature. It was concluded that some synergy had existed between lignite and lower ratios of furniture work dusts, which was indicated by a prompt effect on the volatiles combustion rates. Char combustion rates of blend pellets have depended predominantly on the amount of lignite in the blend. The amounts of combustion residues of the pellets were considerably higher than those calculated from individual ash contents of the raw materials and related to lignite ratio in the blends.

Deveci, N.D.; Yilgin, M.; Pehlivan, D. [Firat University, Elazig (Turkey). Faculty of Engineering

2008-07-01

442

On-Line Measurement of Heat of Combustion of Gaseous Hydrocarbon Fuel Mixtures  

NASA Technical Reports Server (NTRS)

A method for the on-line measurement of the heat of combustion of gaseous hydrocarbon fuel mixtures has been developed and tested. The method involves combustion of a test gas with a measured quantity of air to achieve a preset concentration of oxygen in the combustion products. This method involves using a controller which maintains the fuel (gas) volumetric flow rate at a level consistent with the desired oxygen concentration in the combustion products. The heat of combustion is determined form a known correlation with the fuel flow rate. An on-line computer accesses the fuel flow data and displays the heat of combustion measurement at desired time intervals. This technique appears to be especially applicable for measuring heats of combustion of hydrocarbon mixtures of unknown composition such as natural gas.

Sprinkle, Danny R.; Chaturvedi, Sushil K.; Kheireddine, Ali

1996-01-01

443

Internal Heterogeneous Processes in Aluminum Combustion  

NASA Technical Reports Server (NTRS)

This paper discusses the aluminum particle combustion mechanism which has been expanded by inclusion of gas dissolution processes and ensuing internal phase transformations. This mechanism is proposed based on recent normal and microgravity experiments with particles formed and ignited in a pulsed micro-arc. Recent experimental findings on the three stages observed in Al particle combustion in air and shows the burning particle radiation, trajectory (streak), smoke cloud shapes, and quenched particle interiors are summarized. During stage I, the radiation trace is smooth and the particle flame is spherically symmetric. The temperature measured using a three-color pyrometer is close to 3000 K. Because it exceeds the aluminum boiling point (2730 K), this temperature most likely characterizes the vapor phase flame zone rather than the aluminum surface. The dissolved oxygen content within particles quenched during stage I was below the detection sensitivity (about 1 atomic %) for Wavelength Dispersive Spectroscopy (WDS). After an increase in the radiation intensity (and simultaneous decrease in the measured color temperature from about 3000 to 2800 K) indicative of the transition to stage II combustion, the internal compositions of the quenched particles change. Both oxygen-rich (approx. 10 atomic %) and oxygen-lean (< 1 %) regions are identified within the particles using back-scattered electron imaging and WDS. During stage II, oscillations are observed in particle radiation and the flame and smoke cloud are distorted from their original spherically-symmetric shape. In stage III, particle radiation continues to exhibit oscillations, but its radiation intensity drops and remains at a nearly constant level. The measured temperature decreases to about 2300 K. Also, larger changes in particle velocities are observed, and oxide caps are found on quenched particle surfaces. While these results showed the correlation between the aluminum particle combustion behavior and the evolution of its internal composition, the change from the spherically symmetric to asymmetric flame shape occurring upon the transition from stage I to stage II combustion could not be understood based only on the fact that dissolved oxygen is detected in the particles. The connection between the two phenomena appeared even less significant because in earlier aluminum combustion studies carried in O2/Ar mixtures, flame asymmetry was not observed as opposed to experiments in air or O2/CO mixtures. It has been proposed that the presence of other gases, i.e., hydrogen, or nitrogen causes the change in the combustion regime.

Dreizin, E. L.

1999-01-01

444

Oxy-fuel combustion technology for coal-fired power generation  

Microsoft Academic Search

The awareness of the increase in greenhouse gas emissions has resulted in the development of new technologies with lower emissions and technologies that can accommodate capture and sequestration of carbon dioxide. For existing coal-fired combustion plants there are two main options for CO2 capture: removal of nitrogen from flue gases or removal of nitrogen from air before combustion to obtain

B. J. P. Buhre; L. K. Elliott; C. D. Sheng; R. P. Gupta; T. F. Wall

2005-01-01

445

COMBUSTION ADDITIVES FOR POLLUTION CONTROL - A STATE-OF-THE-ART REVIEW  

EPA Science Inventory

The report is a state-of-the-art review of the potential of combustion-type fuel additives in reducing air pollutant emissions from oil and coal firing. It contains two complementary parts: a review of the relation of combustion mechanisms to additive action in controlling emissi...

446

High compression ratio and efficiency governed self-ignition internal combustion engine  

Microsoft Academic Search

This patent describes an internal combustion engine operable on a fuel capable of being atomized at pressures above atmospheric pressure, which comprises: (a) at least one piston and cylinder defining an internal combustion chamber of compression ratio sufficient to provide self-ignition with the fuel when when mixed therein with air; (b) intake means selectively communicating a first source of the

Bago

1986-01-01

447

PRODUCTS OF INCOMPLETE COMBUSTION FROM DIRECT BURNING OF PENTACHLOROPHENOL-TREATED WOOD WASTES  

EPA Science Inventory

The report gives results of a study to identify potential air pollution problems from the combustion of waste wood treated with pentachlorophenol preservative for energy production in a boiler. The study emphasized the characterization of the products of incomplete combustion (PI...

448

Soot filter for an exhaust arrangement of an internal combustion engine  

Microsoft Academic Search

A soot filter arrangement for an exhaust gas flow of an internal combustion engine, especially an air-compressing internal combustion engine. The filter arrangement includes a housing with feed and discharge connections for the exhaust gas stream in a mineral filter material arranged in the housing. The material is provided on a support pipe equipped with passage openings which enable the

H. Bergmann; H. Daudel; H. Erdmannsdorfer

1982-01-01

449

The Combustive Sound Source  

NASA Astrophysics Data System (ADS)

This thesis describes a unique type of low frequency underwater sound source, the Combustive Sound Source (CSS). The fundamental operating principle of CSS is the following: Electrolysis of water produces hydrogen and oxygen gas, which is a combustible mixture. The gas mixture is captured in a combustion chamber and ignited with a spark. The ensuing combustion produces expanding gases which in turn produce high intensity, low frequency acoustic pulses. The thesis begins by discussing the background of the project and initial feasibility work. It continues by briefly discussing electrolysis and gas production. Fundamental combustion theory is discussed, along with two experiments that relate the acoustic output of CSS to theory. Additional experiments were conducted in order to compare the first bubble period in the CSS pressure signature with the predictions of the Rayleigh-Willis equation. The dependence of the radiated acoustic waveform on the volume and depth of the bubble was investigated. The first bubble period of the CSS pressure signature agrees with Rayleigh-Willis theory in trend, but not in absolute value. Empirical equations are presented which predict the first bubble period for three different situations, a depth of nine meters for various stoichiometric volumes, a stoichiometric volume of 0.5 STP liters for various depths, and a stoichiometric volume of 500 cubic centimeters for various depths. High speed filming of the CSS bubble is presented. The high speed films confirm that CSS produces a bubble of high temperature combustion products. The bubble oscillates and generates acoustic output. The motion of the bubble is shown to be related to the acoustic output in the classic manner, with pressure peaks associated with minimum bubble volumes. Finally, several other factors that affect the acoustic output of CSS are discussed. These include the shape of the CSS combustion chamber, the ignition source, the oxidizer, the presence of high pressure bubble collapses, and the presence of high frequency components.

Wilson, Preston S.

1994-04-01

450

Development and test of combustion chamber for Stirling engine heated by natural gas  

NASA Astrophysics Data System (ADS)

The combustion chamber is an important component for the Stirling engine heated by natural gas. In the paper, we develop a combustion chamber for the Stirling engine which aims to generate 3˜5 kWe electric power. The combustion chamber includes three main components: combustion module, heat exchange cavity and thermal head. Its feature is that the structure can divide "combustion" process and "heat transfer" process into two apparent individual steps and make them happen one by one. Since natural gas can mix with air fully before burning, the combustion process can be easily completed without the second wind. The flame can avoid contacting the thermal head of Stirling engine, and the temperature fields can be easily controlled. The designed combustion chamber is manufactured and its performance is tested by an experiment which includes two steps. The experimental result of the first step proves that the mixture of air and natural gas can be easily ignited and the flame burns stably. In the second step of experiment, the combustion heat flux can reach 20 kW, and the energy utilization efficiency of thermal head has exceeded 0.5. These test results show that the thermal performance of combustion chamber has reached the design goal. The designed combustion chamber can be applied to a real Stirling engine heated by natural gas which is to generate 3˜5 kWe electric power.

Li, Tie; Song, Xiange; Gui, Xiaohong; Tang, Dawei; Li, Zhigang; Cao, Wenyu

2014-04-01

451

Ultra-lean combustion at high inlet temperatures  

NASA Technical Reports Server (NTRS)

Combustion at inlet air temperatures of 1100 to 1250 K was studied for application to advanced automotive gas turbine engines. Combustion was initiated by the hot environment, and therefore no external ignition source was used. Combustion was stabilized without a flameholder. The tests were performed in a 12 cm diameter test section at a pressure of 2.5 x 10 to the 5th power Pa, with reference velocities of 32 to 60 m/sec and at maximum combustion temperatures of 1350 to 1850 K. Number 2 diesel fuel was injected by means of a multiple source fuel injector. Unburned hydrocarbons emissions were negligible for all test conditions. Nitrogen oxides emissions were less than 1.9 g NO2/kg fuel for combustion temperatures below 1680 K. Carbon monoxide emissions were less than 16 g CO/kg fuel for combustion temperatures greater than 1600 K, inlet air temperatures higher than 1150 K, and residence times greater than 4.3 microseconds.

Anderson, D. N.

1981-01-01

452

Combustion in a Bomb with a Fuel-Injection System  

NASA Technical Reports Server (NTRS)

Fuel injected into a spherical bomb filled with air at a desired density and temperature could be ignited with a spark a few thousandths of a second after injection, an interval comparable with the ignition lag in fuel-injection engines. The effect of several variables on the extent and rate of combustion was investigated: time intervals between injection and ignition of fuel of 0.003 to 0.06 second and one of 5 minutes; initial air temperatures of 100 degrees C. to 250 degrees C.; initial air densities equivalent to 5, 10, and 15 absolute atmospheres pressure at 100 degrees C.; and air-fuel ratios of 5 to 25.

Cohn, Mildred; Spencer, Robert C

1935-01-01

453

Numerical modeling of piston secondary motion and skirt lubrication in internal combustion engines  

E-print Network

Internal combustion engines dominate transportation of people and goods, contributing significantly to air pollution, and requiring large amounts of fossil fuels. With increasing public concern about the environment and ...

McClure, Fiona

2007-01-01

454

Investigation of spark discharge processes and ignition systems for spark-ignited internal combustion engines  

E-print Network

Spark ignition of the air-fuel mixture at the appropriate time is important for successful flame initiation and complete combustion thereafter without unnecessary emissions. The physical and chemical reactions taking place between the spark plug...

Khare, Yogesh Jayant

2000-01-01

455

Combustion lean limits fundamentals and their application to a SI hydrogen-enhanced engine concept  

E-print Network

Operating an engine with excess air, under lean conditions, has significant benefits in terms of increased engine efficiency and reduced emissions. However, under high dilution levels, a lean limit is reached where combustion ...

Ayala, Ferran A. (Ferran Alberto), 1976-

2006-01-01

456

National Combustion Code Used To Study the Hydrogen Injector Design for Gas Turbines  

NASA Technical Reports Server (NTRS)

Hydrogen, in the gas state, has been proposed to replace Jet-A (the fuel used for commercial jet engines) as a fuel for gas turbine combustion. For the combustion of hydrogen and oxygen only, water is the only product and the main greenhouse gas, carbon dioxide, is not produced. This is an obvious benefit of using hydrogen as a fuel. The situation is not as simple when air replaces oxygen in the combustion process. (Air is mainly a mixture of oxygen, nitrogen, and argon. Other components comprise a very small part of air and will not be mentioned.) At the high temperatures found in the combustion process, oxygen reacts with nitrogen, and this produces nitrogen oxide compounds, or NOx--the main component of atmospheric smog. The production of NOx depends mainly on two variables: the temperature at which combustion occurs, and the length of time that the products of combustion stay, or reside, in the combustor. Starting from a lean (excess air) air-to-fuel ratio, the goal of this research was to minimize hot zones caused by incomplete premixing and to keep the residence time short while producing a stable flame. The minimization of these two parameters will result in low- NOx hydrogen combustion.

Iannetti, Anthony C.; Norris, Andrew T.; Shih, Tsan-Hsing

2005-01-01

457

Environmentally conscious coal combustion  

SciTech Connect

This is the final report of a one-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The objective of this project was to evaluate the environmental impacts of home-scale coal combustion on the Navajo Reservation and develop strategies to reduce adverse health effects associated with home-scale coal combustion. Principal accomplishments of this project were: (1) determination of the metal and gaseous emissions of a representative stove on the Navajo Reservation; (2) recognition of cyclic gaseous emissions in combustion in home-scale combustors; (3) `back of the envelope` calculation that home-scale coal combustion may impact Navajo health; and (4) identification that improved coal stoves require the ability to burn diverse feedstocks (coal, wood, biomass). Ultimately the results of Navajo home-scale coal combustion studies will be extended to the Developing World, particularly China, where a significant number (> 150 million) of households continue to heat their homes with low-grade coal.

Hickmott, D.D.; Brown, L.F.; Currier, R.P. [and others

1997-08-01

458

Combustion in fluidized beds  

SciTech Connect

Circulating fluidized-bed (CFB) combustion systems have become popular since the late 1970s, and, given the current level of activity in the area,it is clear that this technology has a stable future in the boiler market. For standard coal combustion applications, competition is fierce with mature pulverized-fuel-based (PF) technology set to maintain a strong profile. CFB systems, however, can be more cost effective than PF systems when emission control is considered, and, as CFB technology matures, it is expected that an ever-increasing proportion of boiler installations will utilize the CFB concept. CFB systems have advantages in the combustion of low-grade fuels such as coal waste and biomass. In competition with conventional bubbling beds, the CFB boiler often demonstrates superior carbon burn-out efficiency. The key to this combustion technique is the hydrodynamic behavior of the fluidized bed. This article begins with a description of the fundamental fluid dynamic behavior of the CFB system. This is followed by an examination of the combustion process in such an environme