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1

Coal-water mixture combustion using oxygen-enriched air and staged firing  

Microsoft Academic Search

Coal-water mixture (CWM) combustion experiments using oxygen-enriched air were conducted in an oil-designed 700-hp watertube boiler using a bituminous CWM. The results indicated that the use of oxygen-enriched air increased carbon burnout, reduced uncontrolled fly ash emissions, and reduced combustion air preheating requirements. The boiler efficiency increased because of reduced flue gas heat losses. The improvement in boiler performance compared

Y. C. Fu; G. T. Bellas; J. I. Joubert

1987-01-01

2

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

3

Long term analysis of the biomass content in the feed of a waste-to-energy plant with oxygen-enriched combustion air.  

PubMed

Thermal utilization of municipal solid waste and commercial wastes has become of increasing importance in European waste management. As waste materials are generally composed of fossil and biogenic materials, a part of the energy generated can be considered as renewable and is thus subsidized in some European countries. Analogously, CO(2) emissions of waste incinerators are only partly accounted for in greenhouse gas inventories. A novel approach for determining these fractions is the so-called balance method. In the present study, the implementation of the balance method on a waste-to-energy plant using oxygen-enriched combustion air was investigated. The findings of the 4-year application indicate on the one hand the general applicability and robustness of the method, and on the other hand the importance of reliable monitoring data. In particular, measured volume flows of the flue gas and the oxygen-enriched combustion air as well as corresponding O(2) and CO(2) contents should regularly be validated. The fraction of renewable (biogenic) energy generated throughout the investigated period amounted to between 27 and 66% for weekly averages, thereby denoting the variation in waste composition over time. The average emission factor of the plant was approximately 45 g CO(2) MJ(-1) energy input or 450 g CO(2) kg(-1) waste incinerated. The maximum error of the final result was about 16% (relative error), which was well above the error (<8%) of the balance method for plants with conventional oxygen supply. PMID:21382872

Fellner, Johann; Cencic, Oliver; Zellinger, Günter; Rechberger, Helmut

2011-10-01

4

Oxygen enriched combustion system performance study: Volume 3, Burner tests and combustion modeling: Final report, Phase 1  

Microsoft Academic Search

Oxygen enriched combustion (OEC) has been shown to have significant energy savings potential in industrial furnace applications. High temperature industrial furnaces, such as glass melting furnaces, appear to be the most promising applications for oxygen enriched combustion. In these applications, the principal energy savings result from minimizing the fuel energy required to heat the diluent nitrogen in air. The results

Y. Kwan; A. R. Abele; W. Richter; S. L. Chen; R. Payne; H. Kobayashi; S. L. Silver

1988-01-01

5

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

6

Oxygen-enriched air production for MHD power plants  

NASA Astrophysics Data System (ADS)

An analysis of several of the cryogenic air separation process cycle variations and compression schemes designed to minimize net system power requirements for supplying pressurized, oxygen-enriched air to the combustor of a 2000 MWt (coal input) baseload MHD power plant is presented.

1980-05-01

7

Kinetics of Coal Char Combustion in Oxygen-Enriched Environment  

NASA Astrophysics Data System (ADS)

The influence of oxygen-enriched gaseous atmosphere on coal char combustion was studied. Two different coals, i.e. lignite and bituminous coal, were used as a basic fuel and the reacting gases of oxygen & CO2 were used to simulate flue gas recirculation. Moreover, a broad range of in-furnace conditions, i.e. five temperatures of 873, 973, 1073, 1173, 1273K and five oxygen concentrations of 20, 40, 60, 80, 100%vol., was investigated. Thermogravimetric method of measurement was employed to obtain the processing data on fuel conversion rate under foregoing investigated conditions. For further calculations, simplified Shrinking-Core Model was introduced. Finally, fundamental kinetic parameters, i.e. pre-exponential factor, activation energy and reaction order, were established and then on the basis of their values reaction-controlling regime for coal char combustion in oxygen-enriched environment was predicted. The investigations, financially supported by Polish Government, are a part of Framework Project "Supercritical Coal-fired Power Units".

Czakiert, T.; Nowak, W.

8

Simulation studies of diesel engine performance with oxygen enriched air and water emulsified fuels  

SciTech Connect

A computer simulation code of a turbocharged, turbocompound diesel engine was modified to study the effects of using oxygen-enriched combustion air and water-emulsified diesel fuels. Oxygen levels of 21 percent to 40 percent by volume in the combustion air were studied. Water content in the fuel was varied from 0 percent to 50 percent mass. Simulation studies and a review and analysis of previous work in this area led to the following conclusions about expected engine performance and emissions: the power density of the engine is significantly increased by oxygen enrichment. Ignition delay and particulate emissions are reduced. Combustion temperatures and No{sub x} emissions are increased with oxygen enrichment but could be brought back to the base levels by introducing water in the fuel. The peak cylinder pressure which increases with the power output level might result in mechanical problems with engine components. Oxygen enrichment also provides an opportunity to use cheaper fuel such as No. 6 diesel fuel. Overall, the adverse effects of oxygen enrichment could be countered by the addition of water and it appears that an optimum combination of water content, oxygen level, and base diesel fuel quality may exist. This could yield improved performance and emissions characteristics compared to a state-of-the-art diesel engine. 9 refs., 8 figs.

Assanis, D.N.; Baker, D. (Illinois Univ., Urbana, IL (USA)); Sekar, R.R.; Siambekos, C.T.; Cole, R.L.; Marciniak, T.J. (Argonne National Lab., IL (USA))

1990-01-01

9

Oxygen-enriched air for MHD power plants  

NASA Technical Reports Server (NTRS)

Cryogenic air-separation process cycle variations and compression schemes are examined. They are designed to minimize net system power required to supply pressurized, oxygen-enriched air to the combustor of an MHD power plant with a coal input of 2000 MWt. Power requirements and capital costs for oxygen production and enriched air compression for enrichment levels from 13 to 50% are determined. The results are presented as curves from which total compression power requirements can be estimated for any desired enrichment level at any delivery pressure. It is found that oxygen enrichment and recuperative heating of MHD combustor air to 1400 F yields near-term power plant efficiencies in excess of 45%. A minimum power compression system requires 167 MW to supply 330 lb of oxygen per second and costs roughly 100 million dollars. Preliminary studies show MHD/steam power plants to be competitive with plants using high-temperature air preheaters burning gas.

Ebeling, R. W., Jr.; Cutting, J. C.; Burkhart, J. A.

1979-01-01

10

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.

11

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

12

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

Microsoft Academic Search

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

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

1993-01-01

13

Oxygen-enriched air for co-incineration of organic sludges with municipal solid waste: A pilot plant experiment  

Microsoft Academic Search

Pilot-plant experiments were performed to evaluate the effect of oxygen enrichment on the co-incineration of MSW and organic sludge from a wastewater treatment facility. Combustion chamber temperatures, stack gas concentrations, i.e., CO2 and CO, and the residual oxygen were measured. The maximum ratio of organic sludge waste to total waste input was 30wt.%. Oxygen-enriched air, 22vol.% (dry basis) oxygen, was

Sungmin Chin; Jongsoo Jurng; Jae-Heon Lee; Jin-Huek Hur

2008-01-01

14

Demonstration of oxygen-enriched combustion system on a light-duty vehicle to reduce cold-start emissions  

SciTech Connect

The oxygen content in the ambient air drawn by combustion engines can be increased by polymer membranes. The authors have previously demonstrated that 23 to 25% (concentration by volume) oxygen-enriched intake air can reduce hydrocarbons (HC), carbon monoxide (CO), air toxics, and ozone-forming potential (OFP) from flexible-fueled vehicles (FFVs) that use gasoline or M85. When oxygen-enriched air was used only during the initial start-up and warm-up periods, the emission levels of all three regulated pollutants [CO, nonmethane hydrocarbons (NMHC), and NO{sub x}] were lower than the U.S. EPA Tier II (year 2004) standards (without adjusting for catalyst deterioration factors). In the present work, an air separation membrane module was installed on the intake of a 2.5-L FFV and tested at idle and free acceleration to demonstrate the oxygen-enrichment concept for initial start-up and warm-up periods. A bench-scale, test set-up was developed to evaluate the air separation membrane characteristics for engine applications. On the basis of prototype bench tests and from vehicle tests, the additional power requirements and module size for operation of the membrane during the initial period of the cold-phase, FTP-75 cycle were evaluated. A prototype membrane module (27 in. long, 3 in. in diameter) supplying about 23% oxygen-enriched air in the engine intake only during the initial start-up and warm-up periods of a 2.5-L FFV requires additional power (blower) of less than one horsepower. With advances in air separation membranes to develop compact modules, oxygen enrichment of combustion air has the potential of becoming a more practical technique for controlling exhaust emissions from light-duty vehicles.

Sekar, R.; Poola, R.B.

1997-08-01

15

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

16

Oxygen enriched combustion system performance study: Phase 1, Interim\\/final report: Volume 1, Technical and economic analysis  

Microsoft Academic Search

Technical and economic feasibility of using oxygen enriched combustion (OEC) and preheated oxygen enriched combustion (POEC) for industrial furnace applications was evaluated. The potential for fuel savings and productivity improvements with OEC\\/POEC systems was parametrically analyzed for a broad range of furnace conditions including those for steel heating, glass melting and aluminum melting. The changes in combustion characteristics with OEC

Kobayashi; Hisashi

1987-01-01

17

Oxygen enriched air/natural gas burner system development. Final report, July 1984-September 1989  

SciTech Connect

In order to remain competitive in the global market, energy intensive combustion processes must reduce costs. Air-natural gas combustion is used in many of these processes including heating and melting of glass and metals. These applications are summarized with respect to natural gas consumption and energy efficiency. Oxygen enrichment can increase furnace productivity and reduce operating costs through improved energy efficiency. Commercial air-natural gas burners were shown to be generally limited to 30% enrichment. Since the maximum benefits of oxygen enrichment (high flame temperature and NOx minimization) are achieved with 100% oxygen, a simple retrofit technology was developed to convert air-natural gas burners to fire oxy-fuel. The technology was tested in a ladle preheating process and a glass melting furnace where increased production and fuel savings were observed. In the glass furnace, burner survivability was improved through water cooling. NOx emissions from heating and melting processes have become a significant environmental issue. A computer-based mathematical model was developed to predict the effect of burner firing conditions on NOx levels. The model currently predicts values higher than experimentally observed, but the trend is correct. The data show that conversion of a furnace to 100% oxygen-natural gas can dramatically reduce NOx emissions to well within existing regulations.

Dalton, A.I.; Tyndall, D.W.

1989-11-01

18

Oxygen-enriched air for co-incineration of organic sludges with municipal solid waste: a pilot plant experiment.  

PubMed

Pilot-plant experiments were performed to evaluate the effect of oxygen enrichment on the co-incineration of MSW and organic sludge from a wastewater treatment facility. Combustion chamber temperatures, stack gas concentrations, i.e., CO(2) and CO, and the residual oxygen were measured. The maximum ratio of organic sludge waste to total waste input was 30 wt.%. Oxygen-enriched air, 22 vol.% (dry basis) oxygen, was used for stable combustion. As the co-incineration ratio of the sludge increased, the primary and secondary combustion chamber temperatures were decreased to 900 and 750 degrees C, respectively, approximately 100 degrees C below the proper incineration. However, if the supplied air was enriched with 22 vol.% (dry basis) oxygen content, the incinerator temperature was high enough to burn the waste mixture containing 30 wt.% moisture sludge, with an estimated heating value of 6.72 MJ/kg. There are two main benefits of using oxygen enrichment in the co-incineration. First, the sensible heat can be reduced as the quantity of nitrogen in the flue gas will be decreased. Second, the unburned carbon formation is reduced due to the oxygen-enriched burning of the waste, despite an increase in the sludge co-incineration ratio. PMID:18325752

Chin, Sungmin; Jurng, Jongsoo; Lee, Jae-Heon; Hur, Jin-Huek

2008-12-01

19

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

20

Demonstration of oxygen-enriched air staging at Owens-Brockway glass containers. Quarterly technical progress report for the period August 1, 1996--October 31, 1996  

SciTech Connect

The objective of the program is to demonstrate the use of a previously developed combustion modification technology to reduce NO, emissions from sideport regenerative container glass melters. This technology, known as oxygen-enriched air staging (OEAS), has been demonstrated, and is now being commercialized for endport container glass furnaces. This report focuses on full furnace parametric and long-term testing.

Rue, D.; Abbasi, H.

1997-03-01

21

Development of Sewage Sludge Direct Melting System Using Oxygen Enriched Combustion.  

National Technical Information Service (NTIS)

Based on strict requirements for a smaller volume and more sludge stability than incinceration, Mitsubishi Heavy Industries (MHI) has developed a new sewage sludge direct melting system. The features of this system are that by using oxygen enriched combus...

S. Nishikawa H. Honda K. Tokuda M. Irino S. Okuno

1989-01-01

22

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

SciTech Connect

The performance of a single-cylinder, direct-injection diesel engine was measured with intake oxygen levels of up to 35% and fuel water contents of up to 20%. Because a previous study indicated that the use of a less-expensive fuel would be more economical, two series of tests with No. 4 diesel fuel and No. 2 diesel fuel were conducted. To control the emissions of nitrogen oxides (NO{sub x}), water was introduced into the combustion process in the form of water-emulsified fuel, or the fuel injection timing was retarded. In the first series of tests, compressed oxygen was used; in the second series of tests, a hollow-tube membrane was used. Steady-state engine performance and emissions data were obtained. Test results indicated a large increase in engine power density, a slight improvement in thermal efficiency, and significant reductions in smoke and particulate-matter emissions. Although NO{sub x} emissions increased, they could be controlled by introducing water and retarding the injection timing. The results further indicated that thermal efficiency is slightly increased when moderately water-emulsified fuels are used, because a greater portion of the fuel energy is released earlier in the combustion process. Oxygen-enriched air reduced the ignition delay and caused the heat-release rate and cumulative heat-release rates to change measurably. Even at higher oxygen levels, NO{sub x} emissions decreased rapidly when the timing was retarded, and the amount of smoke and the level of particulate-matter emissions did not significantly increase. The single-cylinder engine tests confirmed the results of an earlier technical assessment and further indicated a need for a low-pressure-drop membrane specifically designed for oxygen enrichment. Extension data set indexed separately. 14 refs.

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

1991-11-01

23

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

National Technical Information Service (NTIS)

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 n...

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

1993-01-01

24

Potential benefits of oxygen-enriched intake air in a vehicle powered by a spark-ignition engine.  

National Technical Information Service (NTIS)

A production vehicle powered by a spark-ignition engine (3.1-L Chevrolet Lumina, model year 1990) was tested. The test used oxygen-enriched intake air containing 25 and 28% oxygen by volume to determine (1) if the vehicle would run without difficulties an...

H. K. Ng R. R. Sekar

1994-01-01

25

Demonstration of oxygen-enriched air staging at Owens-Brockway glass containers. Quarterly technical progress report, November 1, 1996--January 31, 1997  

SciTech Connect

The objective of the program is to demonstrate the use of a previously developed combustion modification technology to reduce NO, emissions from sideport regenerative container glass melters. This technology, known as oxygen-enriched air staging (OEAS), has been demonstrated, and is now being commercialized, for endport container glass furnaces. A 17-month development program has been established with specific objectives to: (1) acquire baseline operating data on the host sideport furnace in Vernon, California, (2) evaluate secondary oxidant injection strategies based on earlier endport furnace results and through modeling of a single port pair, (3) retrofit and test one port pair (the test furnace has six port pairs) with a flexible OEAS system, and select the optimal system configuration, (4) use the results from tests with one port pair to design, retrofit, and test OEAS on the entire furnace (six port pairs), and (5) analyze test results, prepare report, and finalize the business plan to commercialize OEAS for sideport furnaces. The host furnace for testing in this program is an Owens-Brockway 6-port pair sideport furnace in Vernon, California producing 325-ton/d of amber container glass. The baseline NO{sub x} level of this optimized furnace is about 4.0 lb/ton of glass. An anticipated NO{sub x}, reduction of 50% will lower the NO{sub x} production level to below 2 lb/ton. Secondary oxidant staging techniques being considered include oxygen-enriched ambient air staging (OEAS) and oxygen staging (OS).

Rue, D.; Abbasi, H.

1997-03-01

26

Demonstration of oxygen-enriched air staging at Owens-Brockway Glass Containers. Technical progress report, August 1, 1995--July 31, 1996  

SciTech Connect

The objective of the program is to demonstrate the use of a previously developed combustion modification technology to reduce NO, emissions from sideport regenerative container glass melters. This technology, known as oxygen-enriched air staging (OEAS), has been demonstrated, and is now being commercialized, for endport container glass furnaces. A 17-month development program has been established with specific objectives to: (1) acquire baseline operating data on the host sideport furnace in Vernon, California, (2) evaluate secondary oxidant injection strategies based on earlier endport furnace results and through modeling of a single port pair, (3) retrofit and test one port pair (the test furnace has six port pairs) with a flexible OEAS system, and select the optimal system configuration, (4) use the results from tests with one port pair to design, retrofit, and test OEAS on the entire furnace (six port pairs), and (5) analyze test results, prepare report, and finalize the business plan to commercialize OEAS for sideport furnaces. The host furnace for testing in this program is an Owens-Brockway 6-port pair sideport furnace in Vernon, California producing 325-ton/d of amber container glass. The baseline NO{sub x} level of this optimized furnace is about 4.0 lb/ton of glass. An anticipated NO{sub x}, reduction of 50% will lower the NO{sub x} production level to below 2 lb/ton. Secondary oxidant staging techniques being considered include oxygen-enriched ambient air staging (OEAS) and oxygen staging (OS).

Rue, D.; Abbasi, H.

1996-11-01

27

Effects of oxygen enrichment and fuel emulsification on diesel engine performance and emissions.  

National Technical Information Service (NTIS)

Tests on a single-cylinder, direct-injection diesel engine coupled to an oxygen-enriching membrane system were performed. In the effects of injection timing were investigated. An oxygen-enriching membrane was used to supply combustion air. Use of bottled ...

R. R. Sekar W. W. Marr R. L. Cole T. J. Marciniak J. E. Schaus

1991-01-01

28

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

29

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

30

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

31

Experimental evaluation of oxygen-enriched air and emulsified fuels in a single-cylinder diesel engine. Volume 1, Concept evaluation  

SciTech Connect

The performance of a single-cylinder, direct-injection diesel engine was measured with intake oxygen levels of up to 35% and fuel water contents of up to 20%. Because a previous study indicated that the use of a less-expensive fuel would be more economical, two series of tests with No. 4 diesel fuel and No. 2 diesel fuel were conducted. To control the emissions of nitrogen oxides (NO{sub x}), water was introduced into the combustion process in the form of water-emulsified fuel, or the fuel injection timing was retarded. In the first series of tests, compressed oxygen was used; in the second series of tests, a hollow-tube membrane was used. Steady-state engine performance and emissions data were obtained. Test results indicated a large increase in engine power density, a slight improvement in thermal efficiency, and significant reductions in smoke and particulate-matter emissions. Although NO{sub x} emissions increased, they could be controlled by introducing water and retarding the injection timing. The results further indicated that thermal efficiency is slightly increased when moderately water-emulsified fuels are used, because a greater portion of the fuel energy is released earlier in the combustion process. Oxygen-enriched air reduced the ignition delay and caused the heat-release rate and cumulative heat-release rates to change measurably. Even at higher oxygen levels, NO{sub x} emissions decreased rapidly when the timing was retarded, and the amount of smoke and the level of particulate-matter emissions did not significantly increase. The single-cylinder engine tests confirmed the results of an earlier technical assessment and further indicated a need for a low-pressure-drop membrane specifically designed for oxygen enrichment. Extension data set indexed separately. 14 refs.

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

1991-11-01

32

MHD performance calculations with oxygen enrichment  

NASA Technical Reports Server (NTRS)

The impact of oxygen enrichment of the combustion air on the generator and overall plant performance was studied for the ECAS-scale MHD/steam plants. A channel optimization technique is described and the results of generator performance calculations using this technique are presented. Performance maps were generated to assess the impact of various generator parameters. Directly and separately preheated plant performance with varying O2 enrichment was calculated. The optimal level of enrichment was a function of plant type and preheat temperature. The sensitivity of overall plant performance to critical channel assumptions and oxygen plant performance characteristics was also examined.

Pian, C. C. P.; Staiger, P. J.; Seikel, G. R.

1979-01-01

33

Bacterial cellulose production under oxygen-enriched air at different fructose concentrations in a 50-liter, internal-loop airlift reactor  

Microsoft Academic Search

Bacterial cellulose (BC) production by Acetobacter xylinum subsp. sucrofermentans BPR2001 was carried out in a 50-l internal-loop airlift reactor in air at an initial fructose concentration of 40 g\\/l. The BC production rate was 0.059 g\\/l per h. When oxygen-enriched air was supplied instead of air, the BC production rate increased to 0.093 g\\/l per h, and the BC yield

Y. Chao; Y. Sugano; M. Shoda

2001-01-01

34

Technical and economic evaluation of diesel engine with oxygen enrichment and water injection  

Microsoft Academic Search

Technical and economic feasibility of diesel engines for stationary cogeneration applications using oxygen-enriched combustion air, water injection, and low-grade fuels was examined. The effects of these modifications on the diesel engine were studied with a computer simulation: results are presented in a companion paper. Four methods of oxygen enrichment, purchases LOX, cryogenic separation, pressure-swing adsorption (PSA), and membrane enrichment (ME)

R. L. Cole; R. R. Sekar; T. J. Marciniak; F. Stodolsky

1990-01-01

35

Novel Membranes and Processes for Oxygen Enrichment  

SciTech Connect

The overall goal of this project is to develop a membrane process that produces air containing 25-35% oxygen, at a cost of $25-40/ton of equivalent pure oxygen (EPO2). Oxygen-enriched air at such a low cost will allow existing air-fueled furnaces to be converted economically to oxygen-enriched furnaces, which in turn will improve the economic and energy efficiency of combustion processes significantly, and reduce the cost of CO{sub 2} capture and sequestration from flue gases throughout the U.S. manufacturing industries. During the 12-month Concept Definition project: We identified a series of perfluoropolymers (PFPs) with promising oxygen/nitrogen separation properties, which were successfully made into thin film composite membranes. The membranes showed oxygen permeance as high as 1,200 gpu and oxygen/nitrogen selectivity of 3.0, and the permeance and selectivity were stable over the time period tested (60 days). We successfully scaled up the production of high-flux PFP-based membranes, using MTR's commercial coaters. Two bench-scale spiral-wound modules with countercurrent designs were made and parametric tests were performed to understand the effect of feed flow rate and pressure, permeate pressure and sweep flow rate on the membrane module separation properties. At various operating conditions that modeled potential industrial operating conditions, the module separation properties were similar to the pure-gas separation properties in the membrane stamps. We also identified and synthesized new polymers [including polymers of intrinsic microporosity (PIMs) and polyimides] with higher oxygen/nitrogen selectivity (3.5-5.0) than the PFPs, and made these polymers into thin film composite membranes. However, these membranes were susceptible to severe aging; pure-gas permeance decreased nearly six-fold within two weeks, making them impractical for industrial applications of oxygen enrichment. We tested the effect of oxygen-enriched air on NO{sub x} emissions using a Bloom baffle burner at GTI. The results are positive and confirm that oxygen-enriched combustion can be carried out without producing higher levels of NOx than normal air firing, if lancing of combustion air is used and the excess air levels are controlled. A simple economic study shows that the membrane processes can produce O{sub 2} at less than $40/ton EPO{sub 2} and an energy cost of 1.1-1.5 MMBtu/ton EPO{sub 2}, which are very favorable compared with conventional technologies such as cryogenics and vacuum pressure swing adsorption processes. The benefits of integrated membrane processes/combustion process trains have been evaluated, and show good savings in process costs and energy consumption, as well as reduced CO{sub 2} emissions. For example, if air containing 30% oxygen is used in natural gas furnaces, the net natural gas savings are an estimated 18% at a burner temperature of 2,500 F, and 32% at a burner temperature of 3,000 F. With a 20% market penetration of membrane-based oxygen-enriched combustion in all combustion processes by 2020, the energy savings would be 414-736 TBtu/y in the U.S. The comparable net cost savings are estimated at $1.2-2.1 billion per year by 2020, calculated as the value of fuel savings subtracted from the cost of oxygen production. The fuel savings of 18%-32% by the membrane/oxygen-enriched combustion corresponds to an 18%-32% reduction in CO{sub 2} emissions, or 23-40 MM ton/y less CO{sub 2} from natural gas-fired furnaces by 2020. In summary, results from this project (Concept Definition phase) are highly promising and clearly demonstrate that membrane processes can produce oxygen-enriched air in a low cost manner that will lower operating costs and energy consumption in industrial combustion processes. Future work will focus on proof-of-concept bench-scale demonstration in the laboratory.

Lin, Haiqing

2011-11-15

36

Mathematical modeling of MSW combustion and SNCR in a full-scale municipal incinerator and effects of grate speed and oxygen-enriched atmospheres on operating conditions.  

PubMed

The rising popularity of incineration of municipal solid waste (MSW) calls for detailed mathematical modeling and accurate prediction of pollutant emissions. In this paper, mathematical modeling methods for both solid and gaseous phases were employed to simulate the operation of a 450 t/d MSW-burning incinerator to obtain detailed information on the flow and combustion characteristics in the furnace and to predict the amount of pollutant emissions. The predicted data were compared to on-site measurements of gas temperature, gas composition and SNCR de-NO(X) system. The major operating conditions considered in this paper were grate speed and oxygen concentration. A suitable grate speed ensures complete waste combustion. The predictions are as follows: volatile release increases with increasing grate speed, and the maximal value is within the range of 700-800 kg/m(2)h; slow grate speeds result in incomplete combustion of fixed carbon; the gas temperature at slow grate speeds is higher due to adequate oxygenation for fixed carbon combustion, and the deviation reaches 200K; NO(X) emission decreases, but CO emission and O(2) concentrations increase, and the deviation is 63%, 34% and 35%, respectively. Oxygen-enriched atmospheres promote the destruction of most pollutants due to the high oxygen partial pressure and temperature. The furnace temperature, NO production and CO emission increase as the oxygen concentration increases, and the deviation of furnace exit temperature, NO and CO concentration is 38.26%, 58.43% and 86.67%, respectively. Finally, oxygen concentration is limited to below 35% to prevent excessive CO and NO(X) emission without compromising plant performance. The current work greatly helps to understand the operating characteristics of large-scale MSW-burning plants. PMID:20627508

Liang, Zengying; Ma, Xiaoqian

2010-12-01

37

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

38

New insights into enriched-air in-situ combustion  

SciTech Connect

This paper presents the results of 10 enriched-air in-situ combustion-tube tests performed on core from the Athabasca oil sands deposit. The tests show that at high pressures, the use of oxygen-enriched air results in increased low-temperature reactions between the oxygen and the oil, resulting in an increased fuel load and decreased burn stability. Although water injection may enhance the performance of oxygen combustion, it may also lead to increased oxygen storage in the swept zone.

Moore, R.G.; Bennion, D.W.; Belgrave, J.D.M.; Gle, D.N.; Ursenbach, M.G. (Calgary Univ., AB (Canada))

1990-07-01

39

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

40

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

41

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

42

Demonstration of oxygen-enriched air staging at Owens-Brockway glass containers. Final technical report for the period April 1, 1995--February 28, 1997  

SciTech Connect

The overall objective of this program was to demonstrate the use of a previously developed combustion modification technology to reduce NO{sub x} emissions from sideport regenerative container glass melters. Specific objectives were to: acquire baseline operating data on the host sideport furnace, evaluate secondary oxidant injection strategies based on earlier endport furnace results and through modeling of a single port pair, retrofit and test one port pair (the test furnace has six port pairs) with a flexible OEAS system, and select the optimal system configuration, use the results from tests with one port pair to design, retrofit, and test OEAS on the entire furnace (six port pairs), and analyze test results, prepare report, and finalize the business plan to commercialize OEAS for sideport furnaces.

Rue, D.; Abbasi, H.

1997-10-01

43

The Optimization Air Separation Plants for Combined Cycle MHD-Power Plant Applications.  

National Technical Information Service (NTIS)

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 objectiv...

A. J. Juhasz H. Springmann R. Greenberg

1980-01-01

44

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

NASA Technical Reports Server (NTRS)

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 atmosphere. Test results confirm that pure Kapton insulated wire has bad arcing characteristics and ETFE insulated wire is considerably better in air. For certain wires, arc tracking effects are increased at higher oxygen concentrations and significantly increased under vacuum. All tests on different cable insulation materials and in different environments, including enriched oxygen atmospheres, resulted in a more or less rapid extinguishing of all high temperature effects at the beginning of the post-test phase. In no case was a self-maintained fire initiated by the arc.

Koenig, Dieter

1994-01-01

45

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...

46

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

47

Reduction of combustion by-products in WTE plants: O2 enrichment of underfire air in the MARTIN SYNCOM process.  

PubMed

The SYNCOM process involves oxygen enrichment of underfire air, recirculation of flue gas and a combustion control system using infrared thermography of the waste layer on the grate. At the demonstration plant in Coburg, operational reliability and plant availability using SYNCOM could be proven under real disposal conditions with a waste throughput of 7 t/h. Oxygen enrichment of the underfire air promotes the destruction of pollutants due to the high oxygen partial pressures and temperatures. This is then reflected in very low residual amounts of organic combustion by-products in the bottom ash and flue gas from the SYNCOM unit. The flue gas concentrations of organic pollutants are reduced, as compared with conventional operation, by over 35% (for CO, total hydrocarbons and PCDD/F) at the boiler outlet. As the flue gas flow is reduced by oxygen enrichment and flue gas recirculation, the resulting reduction in terms of kg of pollutant per Mg of waste is even higher. In the bottom ash, the level of organic residues is reduced, by 45% in the case of loss on ignition and by 55% in the case of TOC and dioxins (I-TE of PCDD/F). This is due to the higher oxygen partial pressures and the fuel bed temperature which is increased by 135 to 1200 degrees C. Other important features of the process include more intense sintering and thus improved immobilization of the bottom ash, as well as reduced flue gas and fly ash flows. PMID:11219678

Gohlke, O; Busch, M

2001-01-01

48

Oxygen-enriched coincineration of MSW and sewage sludge: Final report  

SciTech Connect

Federal regulations banning ocean dumping of sewage sludge coupled with stricter regulations on the disposal of sewage sludge in landfills have forced municipalities, especially those in the northeast United States, to consider alternate methods for disposal of this solid waste. Coincineration of municipal solid waste (MSW) and sludge has proven to be economically attractive for both Europe and Japan, but has not yet proven to be a viable sludge disposal technology in the United States because of a history of operational problems in existing facilities. The most prevalent problem in coincinerating MSW and a dewatered sewage sludge (15 to 25% solids) is incomplete sludge combustion. Incomplete sludge combustion is primarily a function of sludge particle size, occurring when the surface of the sludge particle dries and hardens, while the inner mass is unaffected. This phenomenon is commonly referred to in the industry as the {open_quotes}hamburger effect.{close_quotes} In an effort to promote technology development in this area, Air Products and Chemicals, Inc. teamed with the US Department of Energy (DOE) through the National Renewable Energy Laboratory (NREL) to evaluate a new process being developed for the disposal of a dewatered sewage sludge, {open_quotes}Oxygen-Enriched Coincineration of MSW and Sewage Sludge.{close_quotes} This report provides a comprehensive summary of the pilot demonstration test program for oxygen-enriched coincineration of MSW and sewage sludge. This report describes the pilot test facility, instrumentation, and methods of data collection and data analyses; describes how the tests were executed; and discusses the test results. Recommendations for the future development of this technology in the current marketplace are also provided.

none,

1994-01-01

49

Evaluation of Oxygen-Enriched MSW/Sewage Sludge Co-Incineration Demonstration Program.  

National Technical Information Service (NTIS)

The report provides an evaluation of a two-phased demonstration program conducted of a recently developed method of sewage sludge management. This method, known as oxygen-enriched co-incineration, is intended to allow the co-combustion of dewatered sewage...

1994-01-01

50

The effect of O 2 enrichment on NO x formation in biomass co-fired pulverised coal combustion  

Microsoft Academic Search

Oxygen enrichment of the combustion air in pulverised coal combustion for power plant is seen as a possible retrofit measure to improve CO2 scrubbing and capture. This technique produces a reduced volume of flue gas with higher CO2 concentration than normal air combustion that will contributes to the enhancement of amine scrubbing plant efficiencies. We report in this article the

W. Nimmo; S. S. Daood; B. M. Gibbs

2010-01-01

51

Properties of air and combustion products of fuel with air  

NASA Technical Reports Server (NTRS)

Thermodynamic and transport properties have been calculated for air, the combustion products of natural gas and air, and combustion products of ASTM-A-1 jet fuel and air. Properties calculated include: ratio of specific heats, molecular weight, viscosity, specific heat, thermal conductivity, Prandtl number, and enthalpy.

Poferl, D. J.; Svehla, R. A.

1975-01-01

52

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

53

Low NOx combustion using cogenerated oxygen and nitrogen streams  

DOEpatents

Combustion of hydrocarbon fuel is achieved with less formation of NOx by feeding the fuel into a slightly oxygen-enriched atmosphere, and separating air into oxygen-rich and nitrogen-rich streams which are fed separately into the combustion device.

Kobayashi, Hisashi (Putnam Valley, NY) [Putnam Valley, NY; Bool, Lawrence E. (East Aurora, NY) [East Aurora, NY; Snyder, William J. (Ossining, NY) [Ossining, NY

2009-02-03

54

Turbulent Methane-Air Combustion  

NASA Technical Reports Server (NTRS)

This study is aimed at enhancing the understanding of turbulent premixed methane-air combustion. Such understanding is essential since: (1) many industries are now pursuing lighter hydrocarbon alternative fuels and the use of premixed flames to reduce pollutant emissions, and (2) the characteristic dimensions and flow rates of most industrial combustors are often large for flows to be turbulent. The specific objectives of the study are: (1) to establish the effects of process variables (e.g., flow rate, fuel/air ratio, chlorinated hydro-carbons, and pressure) on the emissions and flow structure (velocity distribution, streamlines, vorticity and flame shape), and (2) to develop a mechanistic model to explain the observed trends. This includes the acquisition of Dantec FlowMap Particle Image Velocimeter. The design and fabrication of the premixed burner has also been completed. The study is now at the stage of testing of equipment and analytical instruments. The presentation will give details on the tasks completed and on the current and future plans. The project is progressing well and all activities are on schedule. The outlook for the success of the project is bright.

Yaboah, Yaw D.; Njokwe, Anny; James, LaShanda

1996-01-01

55

Combustion heated air turbine starter system  

SciTech Connect

This paper describes a combustion heated air turbine starter system. It comprises: an air turbine starter operatively associated with a main turbine engine; an auxiliary power unit adapted to deliver air through a bleed duct to the air turbine starter; and means for combusting fuel from a source with air from the auxiliary power unit; the combusting means including an auxiliary combustor disposed within the bleed duct upstream of the air turbine starter, the auxiliary combustor including an outer wall positioned in radially inwardly spaced relation to the bleed duct, the outer wall defining an axial combustion air flow path inwardly thereof and an axial bypass air flow path outwardly thereof; the auxiliary combustor including a fuel injector positioned centrally of the outer wall at an open upstream end thereof, the auxiliary combustor also including means for producing a rotating annulus of air about the fuel injector at the open upstream end of the outer wall; the rotating annulus of air causing a laminerized blue flame to be produced in radially inwardly spaced relation to the outer wall and the rotating annulus of air mixing with air in the axial bypass air flow path downstream of the outer wall to produce a flame zone radially inwardly of the bleed duct.

Shekleton, J.R.

1991-10-08

56

A simplified method for determining heat of combustion of natural gas  

NASA Technical Reports Server (NTRS)

A simplified technique for determination of the heat of combustion of natural gas has been developed. It is a variation of the previously developed technique wherein the carrier air, in which the test sample was burnt, was oxygen enriched to adjust the mole fraction of oxygen in the combustion product gases up to that in the carrier air. The new technique eliminates the need for oxygen enrichment of the experimental mixtures and natural gas samples and has been found to predict their heats of combustion to an uncertainty of the order of 1 percent.

Singh, Jag J.; Chegini, Hoshang; Mall, Gerald H.

1987-01-01

57

Early Gaseous Oxygen Enrichment to Enhance Magnetite Pellet Oxidation  

NASA Astrophysics Data System (ADS)

It is suggested that oxygen enrichment in the gas atmosphere, during continuous heating of magnetite pellets, can cause pellets to be oxidized throughout their volumes, eliminating unoxidized cores. The peculiarities of the oxidation kinetics of magnetite concentrate imply that such oxygen enrichment might be particularly effective at lower temperatures. This suggestion was tested by developing and testing a mixed-control model for pellet oxidation (to allow the sizes of unreacted cores to be predicted), and by experimentally testing the effects of oxygen enrichment at relatively low temperatures ("early oxygen enrichment"). The results confirmed that the extents (depth) of oxidation and pellet strength were both improved significantly by applying oxygen enrichment up to 873 K (600 °C), as part of a heating cycle up to 1073 K (800 °C).

Tang, Ming; Cho, Hyeon Jeong; Pistorius, Petrus Christiaan

2014-04-01

58

Evaluation of oxygen-enriched msw/sewage sludge co-incineration demonstration program  

SciTech Connect

The report provides an evaluation of a two-phased demonstration program conducted of a recently developed method of sewage sludge management. This method, known as oxygen-enriched co-incineration, is intended to allow the co-combustion of dewatered sewage sludge with municipal solid waste in a waste-to-energy facility without affecting solid waste throughput capacity or facility operational characteristics. The report describes the demonstration program plan and the tests performed; assesses the execution of the demonstration program; provides the reported test results; and presents the results of an independent verification of the test results. Also evaluated in the report are the technical/operational, environmental regulatory/permitting, and economic implications of the commercial application of oxygen-enriched co-incineration. Finally, overall conclusions and recommendations are provided based on the evaluation.

NONE

1994-09-01

59

Combustion modeling, scaling and air toxins  

Microsoft Academic Search

This volume contains papers presented at the 1994 International Joint Power Generation Conference which was held October 2--6 in Phoenix, Arizona. The purpose of this conference was to provide a forum for exchange of state-of-the-art information relevant to combustion, pollutants emission, and air toxins. The papers focus on the following broad categories: pollutants emissions and combustion modeling; particle transport and

A. K. Gupta; A. Moussa; C. Presser; M. J. Rini; R. Weber; G. Woodward

1994-01-01

60

Retrofitting for Co-combustion of MSW and sewage sludge  

Microsoft Academic Search

Researchers have demonstrated in a pilot-scale test a new technology for co-combusting sewage sludge with MSW in existing WTE combustors. The technology offers municipalities a cost-competitive alternative to land disposal and ocean-dumping of sludge. The key to the new technology is the selective enrichment of the combustion air with oxygen. Oxygen-enrichment enables the combustion of a higher ratio of sludge

D. M. DeVincentis; D. P. Bucci; S. P. Goff; G. H. Shahani

2009-01-01

61

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

62

Supplemental air valve for internal combustion engine  

Microsoft Academic Search

A valve for attachment in the PCV system of an internal combustion engine for regulating the admission of supplemental air to the crank case blow-by return, comprising: (a) a valve body defining a bore, the body having an inlet and an outlet connection defining a passageway through the valve for the blow-by return, the body further defining a port for

Pankow

1987-01-01

63

EFFECTS OF HYBRID REBURNING\\/SNCR STRATEGY ON NOX\\/CO REDUCTION AND THERMAL CHARACTERISTICS IN OXYGEN-ENRICHED LPG FLAME  

Microsoft Academic Search

From the view of the environmental protection against the usage of fossil fuels, a great amount of effort has been exerted to find an effective method that is not only for pollutant reduction, but also for higher thermal efficiency. In order to enhance combustion efficiency, oxygen-enriched combustion is used by increasing the oxygen ratio in the oxidizer. However, since the

CHANG YEOP LEE; SEUNG WOOK BAEK

2007-01-01

64

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

65

Compact Analyzer/Controller For Oxygen-Enrichment System  

NASA Technical Reports Server (NTRS)

System controls hypersonic air-breathing engine tests. Compact analyzer/controller developed, built, and tested in small-scale wind tunnel prototype of the 8' HTT (High-Temperature Tunnel). Monitors level of oxygen and controls addition of liquid oxygen to enrich atmosphere for combustion. Ensures meaningful ground tests of hypersonic engines in range of speeds from mach 4 to mach 7.

Puster, Richard L.; Singh, Jag J.; Sprinkle, Danny R.

1990-01-01

66

Development of materials screening tests for oxygen-enriched environments  

NASA Technical Reports Server (NTRS)

The criteria governing materials to be used in an oxygen enriched atmosphere and tests to determine suitability for fireproof considerations in spacecraft design are discussed. The nine tests applied to materials before acceptance in spacecraft construction are presented. The application of the standard tests to determine ranking of materials is included.

Johnston, R. L.; Pippen, D. L.

1971-01-01

67

Optimization of Air Separation Plants for Combined Cycle MHD-Power Plant Applications.  

National Technical Information Service (NTIS)

Some of the design approaches being employed during a current DOE/NASA supported study directed at developing an improved air separation process for the production of oxygen enriched air for MHD combustion are described. The ultimate objective of the stud...

H. Springmann R. Greenberg A. J. Juhasz

1980-01-01

68

A Novel High-Heat Transfer Low-NOâ Natural Gas Combustion System. Final Technical Report  

Microsoft Academic Search

A novel high-heat transfer low NO(sub x) natural gas combustion system. The objectives of this program are to research, develop, test, and commercialize a novel high-heat transfer low-NOâ natural gas combustion system for oxygen-, oxygen-enriched air, and air-fired furnaces. This technology will improve the process efficiency (productivity and product quality) and the energy efficiency of high-temperature industrial furnaces by at

Abbasi

2004-01-01

69

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

70

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.

Holubcik, Michal; Papucik, Stefan

2014-01-01

71

Asthma aggravation, combustion, and stagnant air  

PubMed Central

BACKGROUND—The relationship between current concentrations of ambient air pollution and adverse health effects is controversial. We report a meteorological index of air stagnation that is associated with daily visits to the emergency department for asthma in two urban areas.?METHODS—Data on daily values of a stagnation persistence index and visits to the emergency department for asthma were collected for approximately two years in Spokane, Washington, USA and for 15months in Seattle, Washington, USA. The stagnation persistence index represents the number of hours during the 24 hour day when surface wind speeds are less than the annual hourly median value, an index readily available for most urban areas. Associations between the daily stagnation persistence index and daily emergency department visits for asthma were tested using a generalised additive Poisson regression model. A factor analysis of particulate matter (PM2.5) composition was performed to identify the pollutants associated with increased asthma visits.?RESULTS—The relative rate of the association between a visit to the emergency department for asthma and the stagnation persistence index was 1. 12 (95% CI 1.05 to 1.19) in Spokane and 1.21 (95% CI 1.09 to 1.35) in Seattle for an increase of 11 and 10 hours, respectively, of low wind speed in a given day. The stagnation persistence index was only correlated with one set of factor loadings; that cluster included the stagnation persistence index, carbon monoxide, and organic/elemental carbon.?CONCLUSION—Increased air stagnation was shown to be a surrogate for accumulation of the products of incomplete combustion, including carbon monoxide and fine particulate levels of organic and elemental carbon, and was more strongly associated with asthma aggravation than any one of the measured pollutants.??

Norris, G.; Larson, T.; Koenig, J.; Claiborn, C.; Sheppard, L.; Finn, D.

2000-01-01

72

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

73

Combustion in a Cross Flow with Air Jet Nozzles  

Microsoft Academic Search

An experimental study was performed on the combustion of a gaseous fuel in a cross inward flow of air through a horizontal array of nozzles. Exhibiting the same aspect of inverse flames, the flame was found to be stabilized with the cross flow configuration near stoichiometric air\\/fuel ratio over the entire investigated range of velocities. Only with excessive air\\/fuel ratios,

M. M. Kamal

2008-01-01

74

Air-Steam Hybrid Engine: An Alternative to Internal Combustion  

National Technical Information Service (NTIS)

In this Small Business Innovation Research (SBIR) Phase 1 project, an energy-efficient air-steam propulsion system has been developed and patented, and key performance attributes have been demonstrated to be superior to those of internal combustion engine...

M. J. Brookman R. Knight

2010-01-01

75

Application of Oxygen-Enriched Aeration in the Conversion of Glycerol to Dihydroxyacetone by Gluconobacter melanogenus IFO 3293  

PubMed Central

Gluconobacter melanogenus 3293 converts glycerol to dihydroxyacetone(DHA) during exponential growth on a yeast extract-phosphate medium at pH 7. The efficiency of this conversion in 25-liter batch fermentations has been found to increase over threefold, when oxygen tension is controlled by increasing the partial pressure of oxygen in the aeration. Conversion of glycerol to DHA does not occur under oxygen-limited fermentation conditions. When the dissolved oxygen tension was maintained at 0.05 atmospheres (using oxygen-enriched air), quantitative conversion of up to 100 g of glycerol/liter to DHA was obtained in 33 h. The amount of glycerol converted can be increased without increasing impeller speed or aeration rate. This increase is not the result of increased production of cell mass. The specific conversion of glycerol to DHA increased from 12.2 g of DHA/g of cell mass at the point of maximum conversion to 35.8 with oxygen enrichment. This increased specific production occurred even though the specific growth rate during the period of oxygen enrichment decreased from 0.23 to 0.06/h. Images

Flickinger, M. C.; Perlman, D.

1977-01-01

76

Comparative study of lean and rich filtration combustion of methane\\/air, ethane\\/air, and propane\\/air mixtures  

Microsoft Academic Search

This work comparatively analyzes lean, rich and ultrarich combustion of methane (CH4)\\/air, ethane (C2H6)\\/air and propane (C3H8)\\/air mixtures inside inert porous media. Temperature, velocity, and chemical products of the combustion waves were studied experimentally in the range of equivalence ratios (?) from 0.2 to 2.5, at a single filtration velocity of 12 cm\\/s. Low-velocity regime (LVR) of filtration gas combustion

MARIO TOLEDO; VALERI BUBNOVICH; ALEXEI SAVELIEV; LAWRENCE KENNEDY

77

Secondary air supply control device in internal combustion engine  

Microsoft Academic Search

A device is described for controlling the supply of secondary air in an internal combustion engine consisting of: three-way catalyst type means for cleaning engine exhaust gas in an engine exhaust pipe; an Oâ sensor in the engine exhaust pipe; means for supplying secondary air to the engine exhaust pipe; control circuit means for receiving the output signal of the

M. Urushidani; S. Oonaka

1986-01-01

78

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

National Technical Information Service (NTIS)

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) ...

J. M. Tishkoff J. P. Drummond T. Edwards A. S. Nejad

2004-01-01

79

Removal of trichlorobenzene using 'oxygen-enriched' highly active absorbent.  

PubMed

Fly ash, industry lime and an additive, Ca(ClO2)2 (C) were used to prepare the 'oxygen-enriched' highly active absorbent (HAA). The influencing factors for removal of 1,2,4-trichlorobenzene (TCB) using this absorbent such as reaction temperature, simulating gas flow rate, oxygen content, etc. were studied in a self-designed reactor. The optimum experimental conditions of removing 1,2,4-TCB are that the content of an oxidizing additive in the absorbent is 3% (wt), simulating gas flow rate is 100 mL/min, reaction temperature is 250 degrees C, and the content of oxygen in simulating gas is 6%. The maximum removal efficiency is 81.71% in 10 mins. The absorption capacity of the absorbent is 0.000111 g/g. The reaction products were determined by gas chromatograph/mass spectrometer (GC/ MS), 2,6-Bis-[1,1-Dimethylethyl]-4-methyl-Phenol is considered to be the major intermediate product. The reaction route was revealed. PMID:21473266

Zhao, Yi; He, Peng; Zhang, Yu-Hai; Ma, Shuangchen

2011-01-01

80

Fuel-Air Mixing and Combustion in Scramjets  

NASA Technical Reports Server (NTRS)

Activities in the area of scramjet fuel-air mixing and combustion associated with the Research and Technology Organization Working Group on Technologies for Propelled Hypersonic Flight are described. Work discussed in this paper has centered on the design of two basic experiments for studying the mixing and combustion of fuel and air in a scramjet. Simulations were conducted to aid in the design of these experiments. The experimental models were then constructed, and data were collected in the laboratory. Comparison of the data from a coaxial jet mixing experiment and a supersonic combustor experiment with a combustor code were then made and described. This work was conducted by NATO to validate combustion codes currently employed in scramjet design and to aid in the development of improved turbulence and combustion models employed by the codes.

Drummond, J. P.; Diskin, Glenn S.; Cutler, A. D.

2002-01-01

81

EFFECTS OF VITIATED AIR ON HYDROGEN IGNITION IN A HIGH-SPEED LAMINAR MIXING LAYER  

Microsoft Academic Search

One associated complication for the use of vitiated air in laboratory supersonic combustion studies to simulate flight enthalpy is that the test media are contaminated by species that are not representative of the actual atmosphere. When burning hydrogen in oxygen-enriched air is employed to produce vitiated air in experimentation, the resulting high-enthalpy airflow contains substantial amounts of, for example, H2O,

B. HAN; C. J. SUNG; M. NISHIOKA

2004-01-01

82

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

83

COMBUSTION CONTROL OF TRACE ORGANIC AIR POLLUTANTS FROM MUNICIPAL WASTE COMBUSTORS  

EPA Science Inventory

The US Environmental Protection Agency (EPA) is considering the use of combustion techniques for controlling air emissions of chlorinated dioxins, chlorinated furans, and other trace organics from municipal waste combustion (MWC) facilities. Recommendations for good combustion pr...

84

EMISIONES AL AIRE DE LA COMBUSTION DE LLANTAS USADAS (SPANISH VERSION)  

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...

85

Asthma aggravation, combustion, and stagnant air  

Microsoft Academic Search

BACKGROUNDThe relationship between current concentrations of ambient air pollution and adverse health effects is controversial. We report a meteorological index of air stagnation that is associated with daily visits to the emergency department for asthma in two urban areas.METHODSData on daily values of a stagnation persistence index and visits to the emergency department for asthma were collected for approximately two

Gary Norris; Timothy Larson; Jane Koenig; Candis Claiborn; Lianne Sheppard; Dennis Finn

2000-01-01

86

Air conditioner for automotive vehicles capable of cooling intake air supplied to an internal combustion engine  

Microsoft Academic Search

An air conditioner is described for use in an automotive vehicle having an internal combustion engine with an intake air system, an intake port and an intake passage, means is arranged in the intake system for compressing intake air, and a passenger compartment, comprising a refrigerant cycle means where a refrigerant is circulated. The refrigerant cycle means comprises: a compressor

Sugiura

1987-01-01

87

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

88

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

89

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...

90

A study of air breathing rockets—Subsonic mode combustion  

NASA Astrophysics Data System (ADS)

Subsonic mode combustion in cylindrical secondary combustors of Air Breathing Rockets (ABR) was investigated. Experiments determined the influence of oxidizer-fuel ratio of the primary rocket, mass flow ratio of secondary air to the primary rocket propellants, and length of secondary combustors on the performance of ABR. Gaseous hydrogen and gaseous oxygen were used as the primary rocket propellants and compressed air at room temperature was used as secondary air. Experimental results were compared with ideal conditions calculated on the assumption of complete mixing and burning. A one-dimensional analysis made it possible to calculate axial distribution of flow properties. From the calculated stagnation temperature distribution, we determined "effective flame length" lf. The performance of the secondary combustors correlated well to the non-dimensional combustor length L/l f. Cross sectional distribution of flow properties were obtained from gas sample and Pitot pressure data. Combustion efficiency was also obtained by integrating heat release flux over an exit cross sectional plane. Using a model assuming incomplete mixing and burning, combustion efficiency and other properties were related to the ratio of the exit pressure to the theoretical projection based on the complete burning model. These results agreed well with the experiments.

Masuya, G.; Chinzei, N.; Ishii, S.

91

Preliminary analysis of 500 MWt MHD power plant with oxygen enrichment. Final report  

SciTech Connect

An MHD Engineering Test Facility design concept is analyzed. A 500 MWt oxygen enriched MHD topping cycle integrated for combined cycle operation with a 400 MWe steam plant is evaluated. The MHD cycle uses Montana Rosebud coal and air enriched to 35 mole percent oxygen preheated to 1100/sup 0/F. The steam plant is a 2535 psia/1000/sup 0/F/1000/sup 0/F reheat recycle that was scaled down from the Gilbert/Commonwealth Reference Fossil Plant design series. Integration is accomplished by blending the steam generated in the MHD heat recovery system with steam generated by the partial firing of the steam plant boiler to provide the total flow requirement of the turbine. The major MHD and steam plant auxiliaries are driven by steam turbines. When the MHD cycle is taken out of service, the steam plant is capable of stand-alone operation at turbine design throttle flow. This operation requires the full firing of the steam plant boiler. The MHD compressors are steam turbine driven instead of electric motor driven which minimizes shifts in main steam turbine flow when operation changes from combined cycle to stand-alone service. A preliminary feasibility assessment is given, and results on the system thermodynamics, construction scheduling, and capital costs are presented. (WHK)

Not Available

1980-04-01

92

Preliminary analysis of 500 MWt MHD power plant with oxygen enrichment  

NASA Astrophysics Data System (ADS)

An MHD Engineering Test Facility design concept is analyzed. A 500 MWt oxygen enriched MHD topping cycle integrated for combined cycle operation with a 400 MWe steam plant is evaluated. The MHD cycle uses Montana Rosebud coal and air enriched to 35 mole percent oxygen preheated to 1100 F. The steam plant is a 2535 psia/1000 F/1000 F reheat recycle that was scaled down from the Gilbert/Commonwealth Reference Fossil Plant design series. Integration is accomplished by blending the steam generated in the MHD heat recovery system with steam generated by the partial firing of the steam plant boiler to provide the total flow requirement of the turbine. The major MHD and steam plant auxiliaries are driven by steam turbines. When the MHD cycle is taken out of service, the steam plant is capable of stand-alone operation at turbine design throttle flow. This operation requires the full firing of the steam plant boiler. A preliminary feasibility assessment is given, and results on the system thermodynamics, construction scheduling, and capital costs are presented.

1980-04-01

93

The effect of inlet air vitiation on combustion efficiency  

SciTech Connect

Experimental results of the effect of inlet air vitiation produced by a vitiating preheater on combustion efficiency of a turbojet combustor and a model ramjet combustor are presented in this paper. An empirical correlation and a calculation method based on stirred reactor theory are derived to correct the vitiation effect. Results obtained by means of these two methods are in good agreement with test data.

Zuomin, F.; Yijun, J.

1985-01-01

94

Combustion gas properties. 2: Natural gas fuel and dry air  

NASA Technical Reports Server (NTRS)

A series of computations has been made to produce the equilibrium temperature and gas composition for natural gas 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. Only samples tables and figures are provided in this report. The complete set of tables and figures is provided on four microfiche films supplied with this report.

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

1985-01-01

95

Supersonic H 2 -air combustions behind oblique shock waves  

Microsoft Academic Search

In order to study the mechanisms of initiation and stabilization of H2-Air combustions (stoechiometric mixture initially atT0=293 K andp0=0.5 bar) in supersonic flow conditions behind an oblique shock wave (OSW), an original technique is used where OSW is generated in this mixture by the lateral expansion of the burnt gas behind a normal CJ gaseous detonation propagating into a bounding

D. Desbordes; L. Hamada; C. Guerraud

1995-01-01

96

Large-Eddy Simulations of Fuel-Air Mixing and Combustion in an Internal Combustion Engine  

NASA Astrophysics Data System (ADS)

Past studies of internal combustion (IC) engine steady-state flow field have employed the well-known KIVA code for steady-state predictions. However, it is also well known that this code is incapable of accurately capturing the impact of unsteady fuel-air mixing on the combustion process. Here, the latest KIVA-3V code has been modified to carry out large-eddy simulations (LES). In particular, the RANS k-e model has been replaced by a subgrid kinetic energy model and a fourth-order ENO scheme has been implemented to increase the accuracy of the discretization of the advection term. Finally, a subgrid model to simulate the small-scale turbulent mixing, combustion and heat release is implemented for reacting flows. Simulations using the new version of KIVA3V denoted here as KIVALES of temporal mixing layers and flows past rearward facing step demonstrate the improved accuracy of the LES model. Accuracy of the prediction is demonstrated by comparing with DNS, LES and experimental results obtained in the past. Finally, the new code is employed to simulate fuel-air mixing and combustion in a typical IC engine. Comparison with predictions using the conventional KIVA is used to demonstrate the ability of the new code.

Sone, Kazuo; Menon, Suresh

2000-11-01

97

Particulate emissions from combustion of biomass in conventional combustion (air) and oxy-combustion conditions  

NASA Astrophysics Data System (ADS)

Oxy-fuel combustion is a viable technology for new and existing coal-fired power plants, as it facilitates carbon capture and thereby, can reduce carbon dioxide emissions. The use of biomass as an energy source is another popular strategy to reduce carbon dioxide emissions as they are considered nearly carbon dioxide neutral. If the use of biomass is combined with oxy-fuel combustion, negative net emissions of carbon dioxide are possible. This work examined the particulate emissions from combustion of pulverized biomass residues burning in either conventional or oxy-fuel environments. Combustion of three biomasses (olive residue, corn residue, and torrefied pine sawdust) occurred in a laboratory-scale laminar-flow drop tube furnace (DTF) heated to 1400 K. The O2 mole fraction was increased from 20% to 60% in N2 environments while a range of 30% to 60% O2 mole fractions were used in CO2 environments to represent plausible dry oxy-fuel combustion conditions. Submicron particulate matter (PM1) emission yields of all three fuels were typically lower in O2/CO2 environments than in O2/N2 environments. When the oxygen mole fraction was increased, the PM1 yields typically increased. The mass fractions of submicron particulate matter (PM1/PM18) collected from biomass combustion were higher than those of coal combustion. PM 1 constituted approximately 50 wt% of the collected ash particles in PM18 in each environment, whereas the corresponding submicron emissions from coal constituted approximately 20 wt%. Changing the background gas had little effect on the chemical composition of the PM1 particles. Unlike the submicron particles collected from coal which contained high amounts of silicon and aluminum, high amounts of alkalis (potassium, calcium, and sodium) and chlorine were the major elements observed in PM1 from the biomasses. In addition, phosphorous and sulfur also existed in high amounts in PM1 of corn residue. Super-micron particles (PM1-18) yields exhibited no clear trend when the background gas was changed or when the oxygen mole fraction was increased. The composition of these particles reflected the bulk ash composition of the parent fuels. Olive residue resulted in by far the largest particulate yields, while torrefied pine sawdust had the lowest. The yields of these two biomasses were analogous with the ash contents of the parent fuels. The particulate yields of corn residue, however, were lower than expected when compared to the parent fuel's ash content. This was attributed to the high phosphorous and sulfur contents of this fuel which might have increased its deposition tendencies in the laboratory furnace.

Ruscio, Amanda Deanne

98

Fuel-Air Mixing and Combustion in Scramjets. Chapter 6  

NASA Technical Reports Server (NTRS)

At flight speeds, the residence time for atmospheric air ingested into a scramjet inlet and exiting from the engine nozzle is on the order of a millisecond. Therefore, fuel injected into the air must efficiently mix within tens of microseconds and react to release its energy in the combustor. The overall combustion process should be mixing controlled to provide a stable operating environment; in reality, however, combustion in the upstream portion of the combustor, particularly at higher Mach numbers, is kinetically controlled where ignition delay times are on the same order as the fluid scale. Both mixing and combustion time scales must be considered in a detailed study of mixing and reaction in a scramjet to understand the flow processes and to ultimately achieve a successful design. Although the geometric configuration of a scramjet is relatively simple compared to a turbomachinery design, the flow physics associated with the simultaneous injection of fuel from multiple injector configurations, and the mixing and combustion of that fuel downstream of the injectors is still quite complex. For this reason, many researchers have considered the more tractable problem of a spatially developing, primarily supersonic, chemically reacting mixing layer or jet that relaxes only the complexities introduced by engine geometry. All of the difficulties introduced by the fluid mechanics, combustion chemistry, and interactions between these phenomena can be retained in the reacting mixing layer, making it an ideal problem for the detailed study of supersonic reacting flow in a scramjet. With a good understanding of the physics of the scramjet internal flowfield, the designer can then return to the actual scramjet geometry with this knowledge and apply engineering design tools that more properly account for the complex physics. This approach will guide the discussion in the remainder of this section.

Drummond, J. Philip; Diskin, Glenn S.; Cutler, Andrew D.

2006-01-01

99

An experimental study on high temperature and low oxygen air combustion  

Microsoft Academic Search

High temperature preheated and diluted air combustion has been confirmed as the technology, mainly applied to industrial furnaces and kilns, to realize higher thermal efficiency and lower emissions. The purpose of this study was to investigate fundamental aspects of the above-mentioned combustion experimentally and to compare with those in ordinary hydrocarbon combustion with room temperature air. The test items were

W. B. Kim; D. H. Chung; J. B. Yang; D. S. Noh

2000-01-01

100

Experimental study of stages in aluminum particle combustion in air  

SciTech Connect

Aluminum is widely used in solid propellants and explosives, and thus Al particle combustion is of great practical interest. Uniform Al particles were formed and ignited in air using a pulsed micro-arc discharge. Burning particle color temperatures were measured using a three-wavelength pyrometer, partially burned particles were quenched and cross-sectioned. Particle internal compositions were studied using a scanning electron microscope equipped with an X-ray energy dispersive spectroscopy detector and wavelength dispersive spectroscopy scan. Temporal variations of the particle diameter and the shape and size of the smoke cloud surrounding a burning particle were determined. The effect of an external electric field on Al particle combustion was also tested. Three distinct stages were identified in Al particle combustion, which correspond to different temperatures, internal particle compositions, and flame shapes. The transitions between the stages were shown to correlate with the internal phase transformations occurring in the burning Al droplets. Growing on spinning Al particles oxide caps were shown to cause rapid changes of trajectories of the burning particles. The temperature histories of burning Al particles were affected by the electric field, and a reduction in the total combustion time due to external electric fields was observed.

Dreizin, E.L. [AeroChem Research Labs., Inc., Princeton, NJ (United States)] [AeroChem Research Labs., Inc., Princeton, NJ (United States)

1996-06-01

101

Supersonic H2-air combustions behind oblique shock waves  

NASA Astrophysics Data System (ADS)

In order to study the mechanisms of initiation and stabilization of H2-Air combustions (stoechiometric mixture initially at T 0=293 K and p 0=0.5 bar) in supersonic flow conditions behind an oblique shock wave (OSW), an original technique is used where OSW is generated in this mixture by the lateral expansion of the burnt gas behind a normal CJ gaseous detonation propagating into a bounding reactive mixture. Four Mach number M of propagation of OSW are considered in the study, namely M=7.7-6.1-4.4 and 3. Depending on the Mach number M and inclinaison angle ? of OSW different regimes of combustion may occur in the driven mixture. For high values of M (6.1 and 7.7) delayed steady overdriven oblique detonation waves (SODW) were obtained with a near CJ detonation wave as the critical regime. It was found that SODW obtained correspond quite well to prediction of the polar method. When thermal conditions behind the OSW are lower, either for high Mach number 6.1 and 7.7 for smaller angle ? than the previous case, or for lower Mach number, 4.4 and 3, the flame initiated at the apex is stabilized as a turbulent oblique flame behind the OSW. With much lower conditions, no combustion appears in the H2-Air mixture.

Desbordes, D.; Hamada, L.; Guerraud, C.

1995-04-01

102

Centrifugation. A theoretical study of oxygen enrichment by centrifugation.  

National Technical Information Service (NTIS)

In the present paper we first investigate what happens if we fill a cylinder with air, close it and rotate it. The results show that no matter which peripheral speed is used, it is not possible by means of the radial separation effect alone, to enrich the...

P. Kierkegaard E. Raetz

1998-01-01

103

Species measurements in a hypersonic, hydrogen-air, combustion wake  

SciTech Connect

A continuously sampling, time-of-flight mass spectrometer has been used to measure relative species concentrations in a two-dimensional, hydrogen-air combustion wake at mainstream Mach numbers exceeding 5. The experiments, in a free piston shock tunnel, yielded distributions of hydrogen, oxygen, nitrogen, water, and nitric oxide at stagnation enthalpies ranging from 5.6 MJ/kg to 12.2 MJ/kg and at a distance of approximately 100s times the thickness of the initial hydrogen jet. The amount of hydrogen mixed in stoichiometric proportions was approximately independent of the stagnation enthalpy, despite the fact that the proportion of hydrogen in the wake was increased with stagnation enthalpy. Roughly 50% of the mixed hydrogen underwent combustion at the highest enthalpy. The proportion of hydrogen reacting to water could be approximately predicted using reaction rates based on mainstream temperatures.

Skinner, K.A.; Stalker, R.J. [Univ. of Queensland, Brisbane, Queensland (Australia)] [Univ. of Queensland, Brisbane, Queensland (Australia)

1996-09-01

104

RESEARCH AREA -- MUNICIPAL WASTE COMBUSTION (AIR POLLUTION TECHNOLOGY BRANCH, AIR POLLUTION PREVENTION AND CONTROL DIVISION, NRMRL)  

EPA Science Inventory

The municipal waste combustion (MWC) program supports the development of revised rules for air pollutant emissions from the MWC source category. Basic research is performed on MWC pollutant formation and control mechanisms for acid gas, trace organic, and trace metal emissions. T...

105

Apparatus for controlling inlet air flow in a turbocharged internal combustion engine  

Microsoft Academic Search

This patent describes an apparatus for controlling inlet air flow in an internal combustion engine having a turbo-supercharger. The turbo-supercharge having a turbine driven by a pressure of an exhaust gas and an air compressor actuated by the turbine and connected to a combustion chamber of the engine through at least two intake passages so that inlet air compressed thereby

Mizutani

1988-01-01

106

Some principles of combustion of homogeneous fuel-air mixtures in the cylinder of an internal combustion engine  

Microsoft Academic Search

An algorithm is presented for the problem of flame propagation rate in combustion of a homogeneous fuel-air mixture in the cylinder of an internal combustion engine. It is assumed that the mixture is not ``overturbulized'' and that the flame front is spherical. The model used for the phenomenon is based on a turbulent transport mechanism. In the near-wall region the

R. M. Petrichenko; A. B. Kanishchev; L. A. Zakharov; Bassam Kandakzhi

1990-01-01

107

Hydrogen-Air Combustion in a Spherical Combustion Chamber with Central Ignition and Comparison of the Results with Kinetic Calculations.  

National Technical Information Service (NTIS)

In order to get information on flame velocities and temperatures during the combustion of a hydrogen-air mixture, one determined pressure cruves of and carried out optical measurements with a spherical, centrally ignited combusition bomb. Details of the m...

W. Sehn

1985-01-01

108

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

109

Horizontal vent air terminal for sealed combustion furnaces. [Design of fresh air intake for furnace with horizontal flue pipe  

Microsoft Academic Search

An air terminal for a horizontal vent of a sealed combustion furnace includes a faceplate for mounting to an exterior vertical wall. A horizontal flue pipe extension, receiving the combustion products, is surrounded by an oval sleeve. Fresh air is communicated to the furnace through the space between the flue pipe and the sleeve. The outlet of the flue pipe

M. E. Winters; P. E. Proctor

1976-01-01

110

Soot and NO formation in methane–oxygen enriched diffusion flames  

Microsoft Academic Search

NO and soot formation were investigated both numerically and experimentally in oxygen-enriched counterflow diffusion flames. Two sets of experiments were conducted. In the first set, the soot volume fraction was measured as a function of oxygen content in the oxidizer jet at constant strain rate (20 s?1). In the second set of experiments, the soot volume fraction was measured as

A. BELTRAME; P. PORSHNEV; W. MERCHAN-MERCHAN; A. SAVELIEV; A. FRIDMAN; L. A. KENNEDY; O. PETROVA; S. ZHDANOK; F. AMOURI; O. CHARON

2001-01-01

111

ROTARY KILN INCINERATION: THE EFFECT OF OXYGEN ENRICHMENT ON FORMATION OF TRANSIENT PUFFS DURING BATCH INTRODUCTION OF HAZARDOUS WASTES  

EPA Science Inventory

The paper discusses results of experiments on a 73 kW (250,000 Btu/hr) rotary kiln incinerator simulator equipped with a prototype oxygen enrichment burner, to determine the effect of oxygen enrichment on the magnitude and intensity of transient puffs emitted during batch introdu...

112

New Compressor Added to Glenn's 450- psig Combustion Air System  

NASA Technical Reports Server (NTRS)

In September 1999, the Central Process Systems Engineering Branch and the Maintenance and the Central Process Systems Operations Branch, released for service a new high pressure compressor to supplement the 450-psig Combustion Air System at the NASA Glenn Research Center at Lewis Field. The new compressor, designated C-18, is located in Glenn s Central Air Equipment Building and is remotely operated from the Central Control Building. C-18 can provide 40 pounds per second (pps) of airflow at pressure to our research customers. This capability augments our existing system capacity (compressors C 4 at 38 pps and C-5 at 32 pps), which is generated from Glenn's Engine Research Building. The C-18 compressor was originally part of Glenn's 21-Inch Hypersonic Tunnel, which was transferred from the Jet Propulsion Laboratory to Glenn in the mid-1980's. With the investment of construction of facilities funding, the compressor was modified, new mechanical and electrical support equipment were purchased, and the unit was installed in the basement of the Central Air Equipment Building. After several weeks of checkout and troubleshooting, the new compressor was ready for long-term, reliable operations. With a total of 110 pps in airflow now available, Glenn is well positioned to support the high-pressure air test requirements of our research customers.

Swan, Jeffrey A.

2000-01-01

113

Numerical Study of High-Temperature Air Combustion Using Different Jet Nozzle  

Microsoft Academic Search

High-Temperature Air Combustion (HTAC) is an advanced combustion technology with the advantage of energy saving and low nitrogen oxide pollutant emission. A swirling burner was designed to further improve the HTAC performance and a numerical simulation was carried out based on CFD technology to investigate the combustion process of methane under different jet parameters. The RSM turbulence model was used

Cui-wu Chen; Ya-xin Su; Hao Cheng

2011-01-01

114

Secondary air supply system for the exhaust system of an internal combustion engine  

Microsoft Academic Search

A description is given of a secondary air supply system for the exhaust system of an internal combustion engine, comprising a source of compressed air, an air control valve which supplies a part of the air delivered from the source to the exhaust system of the engine while relieving the rest of the air, an oxygen detector for detecting residual

Hattori

1980-01-01

115

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

116

An experimental study on high temperature and low oxygen air combustion  

Microsoft Academic Search

High temperature preheated and diluted air combustion has been confirmed as the technology, mainly applied to industrial furnaces\\u000a and kilns, for realizing higher thermal efficiency and lower emissions. The purpose of this study was to investigate fundamental\\u000a aspects of the above-mentioned combustion experimentally and to compare with those in ordinary hydrocarbon combustion with\\u000a room temperature air. The test items were

Dae Hun Chung; Jae Bok Yang; Dong Sun Noh; Won Bae Kim

1999-01-01

117

An experimental study on high temperature and low oxygen air combustion  

Microsoft Academic Search

High temperature preheated and diluted air combustion has been confirmed as the technology, mainly applied to industrial furnaces\\u000a and kilns, to realize higher thermal efficiency and lower emissions. The purpose of this study was to investigate fundamental\\u000a aspects of the above-mentioned combustion experimentally and to compare with those in ordinary hydrocarbon combustion with\\u000a room temperature air. The test items were

W. B. Kim; D. H. Chung; J. B. Yang; D. S. Noh

2000-01-01

118

Intake air meter for an internal combustion engine  

SciTech Connect

An intake air meter for an internal combustion engine is described, comprising: a Karman vortex shedder disposed in the main air intake passageway of the engine; means for generating and receiving ultrasonic waves and producing a corresponding electrical output signal, the means being disposed on opposite sides of the main air intake passageway downstream of the vortex shedder such that a Karman vortex street which is shed by the shedder will pass therebetween; means for driving the ultrasonic transmitter so as to generate the ultrasonic waves; means for shaping the output signal of the ultrasonic receiver; means for producing an output signal corresponding to the phase difference between a first input signal which is the output signal from the first waveform shaping means and a second input signal; means for removing unwanted frequency components from the output signal of the phase comparator; means for shifting the phase of the output signal from the oscillator means in accordance with the voltage of the output signal from the loop filter means and for providing a phase-shifted output as the second input signal to the phase comparator means; and means for removing a carrier frequency component from the output signal of the phase comparator means.

Tada, Y.; Abe, M.

1989-03-28

119

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

120

Observations on the combustion of boron slurry droplets in air  

SciTech Connect

Single fiber-supported slurry droplets composed of boron in JP-10 were ignited and burned in room-temperature air. Initial droplet diameters ranged from 1.2 to 3.0 mm and initial boron weight fractions f from 0 to 0.7. It was observed that although the liquid fuel apparently burns completely the boron does not ignite under these experimental conditions. For the pure liquid the combustion is smooth with a measured burning-rate constant of 0.43 mm/sup 2//s. At low f there is periodic swelling of the droplet with mildly disruptive emission of gas from the interior; the severity of this irregularity is greatest for f approx. = 0.1 and negligible for f greater than or equal to 0.2. For f less than or equal to 0.4 a reduction in droplet diameter, according to a d/sup 2/ law, is observed for a period of time, followed by a burning period of essentially constant diameter. For f greater than or equal to 0.5, the droplet diameter remains practically constant during combustion, although the measured burning time conforms to a d/sup 2/ law. These observations are compared quantitatively with theoretical predictions and are found to agree within accuracies ranging from 10% to 25%.

Antaki, P.; Williams, F.A.

1987-01-01

121

Some principles of combustion of homogeneous fuel-air mixtures in the cylinder of an internal combustion engine  

NASA Astrophysics Data System (ADS)

An algorithm is presented for the problem of flame propagation rate in combustion of a homogeneous fuel-air mixture in the cylinder of an internal combustion engine. It is assumed that the mixture is not “overturbulized” and that the flame front is spherical. The model used for the phenomenon is based on a turbulent transport mechanism. In the near-wall region the combustion mechanism follows a fine-scale mechanism, but in the core, a large-scale mechanism. Experiments permitted determination of the character and numerical value of coefficients which consider the effect of turbulence on flame front propagation in the combustion chamber of a ZMZ-4021 engine. The principles presented can be used as the basis of an algorithm for heat liberation rate in an internal combustion engine with external mixture formation.

Petrichenko, R. M.; Kanishchev, A. B.; Zakharov, L. A.; Kandakzhi, Bassam

1990-12-01

122

Apparatus for controlling the proportion of air and fuel in an air-fuel mixture of the international combustion engine  

Microsoft Academic Search

An apparatus for controlling the proportion of air and fuel in the air-fuel mixture of the internal combustion engine includes a carburetor having a main system fuel tube, a main system air-bleeding passage, a slow system fuel tube and a slow system air-bleeding passage, and a proportional control solenoid valve including an air-inlet port, a first outlet port communicating with

M. Akagi; K. Hattori; K. Kato; I. Nomura

1984-01-01

123

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

124

Adaptation of Combustion Principles to Aircraft Propulsion. Volume I; Basic Considerations in the Combustion of Hydrocarbon Fuels with Air  

NASA Technical Reports Server (NTRS)

The report summarizes source material on combustion for flight-propulsion engineers. First, several chapters review fundamental processes such as fuel-air mixture preparation, gas flow and mixing, flammability and ignition, flame propagation in both homogenous and heterogenous media, flame stabilization, combustion oscillations, and smoke and carbon formation. The practical significance and the relation of these processes to theory are presented. A second series of chapters describes the observed performance and design problems of engine combustors of the principal types. An attempt is made to interpret performance in terms of the fundamental processes and theories previously reviewed. Third, the design of high-speed combustion systems is discussed. Combustor design principles that can be established from basic considerations and from experience with actual combustors are described. Finally, future requirements for aircraft engine combustion systems are examined.

Barnett, Henry C (Editor); Hibbard, Robert R (Editor)

1955-01-01

125

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

126

Air-fuel ratio controlling system for an internal combustion engine  

Microsoft Academic Search

An air-fuel ratio controlling system for a fuel-injection type internal combustion engine has an air valve disposed in an air intake duct upstream of a throttle valve and a fuel-metering variable orifice disposed in a fuel circuit. The air valve and the fuel-metering variable orifice are operatively associated with each other and controlled normally to maintain the air-fuel ratio at

T. Ando; M. Minoura; K. Motosugi; S. Sekiya; M. Sumiyoshi; Y. Takeuchi; J. Uozumi

1980-01-01

127

Air-fuel ratio control apparatus of a fuel supply system for an internal combustion engine  

Microsoft Academic Search

An air-fuel ratio control apparatus for an internal combustion engine has an air valve disposed in an intake passage downstream of a throttle valve to cooperate therewith to define an air pressure chamber and operative to maintain a substantially constant pressure therein. A fuel circuit includes a fuel discharge port open to the intake passage and a fuel-metering orifice operatively

T. Ando; M. Minoura; K. Motosugi; S. Sekiya; M. Sumiyoshi; Y. Takeuchi; J. Uozumi

1980-01-01

128

Control circuit for use with air-diverter valve of internal combustion engine  

Microsoft Academic Search

An electronic control circuit is described for actuating an air-diverter valve connected with the exhaust system of an internal combustion engine to supply air thereto, comprising in combination: (a) means responsive to engine speed, for operating the air diverter valve toward its closing position if a predetermined time interval has elapsed with the engine running above a given speed, and

Lupoli

1986-01-01

129

Air supply and venting to improve performance of residential combustion appliances  

SciTech Connect

With homes being made tighter, combustion appliances are having an increasingly difficult time receiving adequate air to operate safely and properly. Spillage of incomplete combustion products or even chimney flow reversals (backdrafting) can result in significant amounts of carbon monoxide and other toxic combustion products being exhausted into the house. Some of these pollutants may cause immediate acute, even life threatening problems; others may cause longer term chronic health problems. Concern about the quality of indoor air has increased commensurately, with international technical organizations (eg. ASHRAE, APCA) identifying it as a major problem. The causes of spillage and backdrafting cannot be attributed to a single component of the combustion system. Conventional appliances, lacking in forced draft generators, must rely on natural draft created by the temperature difference between the flue gas and the outdoor air. Unfortunately, large quantities of dilution air and/or poorly designed systems result in large quantities of lukewarm stack gas which translate into poor draft. In other cases, the chimney itself may be at fault either through being oversized, physical deterioration or poor location. Again the result is poor draft and possible combustion product spillage or backdrafting. The elimination of these problems must therefore address not only the combustion appliances but also the chimney and associated venting system. This book discusses gas-or oil-fired combustion systems, which eliminate the dilution device and forcibly exhaust the combustion products.

Hayden, A.C.S.; Preto, F. (Canadian Combustion Research Lab., Ottawa, Ontario (CA))

1988-01-01

130

Sooting and disruption in spherically symmetrical combustion of decane droplets in air  

NASA Technical Reports Server (NTRS)

The paper presents the results of experiments on the burning of individual 1-2 mm decane droplets in air at room temperature and atmospheric pressure. The NASA Lewis 2.2 s drop tower was used as well as a newly designed droplet-combustion apparatus that promotes nearly spherically symmetrical combustion. Unanticipated disruptions related to sooting behavior were encountered.

Dryer, F. L.; Williams, F. A.; Haggard, J. B., Jr.; Shaw, B. D.

1987-01-01

131

Development of fire resistant electronic configurations for use in oxygen enriched environments  

NASA Technical Reports Server (NTRS)

Design concepts for electronic black boxes and modules were tested in oxygen enriched atmospheres, and it was found that various types of sealed configurations would generally eliminate any flammability hazard. The type of configuration and its construction was found to be of more importance in the elimination of flammability hazards in electronic configurations than the types of materials utilized in them. The design concepts developed for fire hazard free electronic configurations for use in manned space programs are applicable for the design of electronic hardware for any use or environment.

Smith, F. J.

1975-01-01

132

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

Microsoft Academic Search

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

Tuttle

1978-01-01

133

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

Microsoft Academic Search

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

Tuttle; Kenneth L

1980-01-01

134

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

Microsoft Academic Search

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

Tuttle

1980-01-01

135

Experimental investigations on adsorption air-conditioner used in internal-combustion locomotive driver-cabin  

Microsoft Academic Search

An internal-combustion locomotive driver-cabin adsorption air-conditioner is a new type of space cooling system, which employs zeolite-water as working pairs and is driven by the waste heat from the exhaust gas of internal-combustion engines. Experiment methodology of this air-conditioner is presented and the results and their impact factors are discussed. Refrigeration output performances under adiabatic and cooling conditions are analyzed

S. Jiangzhou; R. Z. Wang; Y. Z. Lu; Y. X. Xu; J. Y. Wu

2002-01-01

136

LES modelling of air and oxy-fuel pulverised coal combustion—impact on flame properties  

Microsoft Academic Search

Large eddy simulations (LES) are used in a CFD model to simulate air- and oxy-fired pulverised coal combustion in a 0.5MWth combustion test facility. Simulations are carried out using two different burners, namely, a triple-staged low-NOx wall fired burner and an IFRF Aerodynamically Air-Staged Burner (AASB). Non-gray radiation is considered in order to deal with the spectral nature of absorption

P. Edge; S. R. Gubba; L. Ma; R. Porter; M. Pourkashanian; A. Williams

2011-01-01

137

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

138

Use of fluidic oscillator to measure fuel-air ratios of combustion gases  

NASA Technical Reports Server (NTRS)

A fluidic oscillator was investigated for use in measuring fuel-air ratios in hydrocarbon combustion processes. The oscillator was operated with dry exhaust gas from an experimental combustor burning ASTM A-1 fuel. Tests were conducted with fuel-air ratios between 0.015 and 0.031. Fuel-air ratios determined by oscillator frequency were within 0.001 of the values computed from separate flow measurements of the air and fuel.

Riddlebaugh, S. M.

1974-01-01

139

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...

140

Megacity and country emissions from combustion sources-Buenos Aires-Argentina  

Microsoft Academic Search

Historic time series (1970-2006) emissions of greenhouse gases and air pollutants arising from stationary and mobile combustion sources were estimated at national level for Argentina and at regional level for the metropolitan area of Buenos Aires (MABA). All emissions were estimated using a bottom-up approach following the IPCC good practice guidance. For mobile sources, national emissions include all transport categories.

L. Dawidowski; D. Gomez; M. Matranga; A. D'Angiola; G. Oreggioni

2010-01-01

141

Combustion of Gaseous Fuels with High Temperature Air in Normal- and Micro-gravity Conditions  

NASA Technical Reports Server (NTRS)

The objective of this study is determine the effect of air preheat temperature on flame characteristics in normal and microgravity conditions. We have obtained qualitative (global flame features) and some quantitative information on the features of flames using high temperature combustion air under normal gravity conditions with propane and methane as the fuels. This data will be compared with the data under microgravity conditions. The specific focus under normal gravity conditions has been on determining the global flame features as well as the spatial distribution of OH, CH, and C2 from flames using high temperature combustion air at different equivalence ratio.

Wang, Y.; Gupta, A. K.

2001-01-01

142

Apparatus for controlling the air fuel mixture of an internal combustion engine  

SciTech Connect

A fuel feeding apparatus for internal combustion engines comprises an area type air flow rate measuring section in which the air flow rate is dependent on the displacement of an air flow rate detecting valve, and a fuel flow rate measuring and distributing section in which a variable orifice defined by a rotor and a stator determines the fuel flow rate proportional to the air flow rate. This apparatus is characterized by the provision of an exhaust gas sensor disposed in the exhaust pipe for the detection of the oxygen concentration of the exhaust gas in order to achieve the complete combustion of fuel in the internal combustion engine, the output signal from the exhaust gas sensor being used to compensate the fuel feeding pressure and a spring force which acts on the pressure difference setting diaphragm of a servo-mechanism.

Harada, H.; Kimata, K.; Nakazeki, T.

1980-06-03

143

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

144

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

145

Characteristics of Gaseous Diffusion Flames with High Temperature Combustion Air in Microgravity  

NASA Technical Reports Server (NTRS)

The characteristics of gaseous diffusion flames have been obtained using high temperature combustion air under microgravity conditions. The time resolved flame images under free fall microgravity conditions were obtained from the video images obtained. The tests results reported here were conducted using propane as the fuel and about 1000 C combustion air. The burner included a 0.686 mm diameter central fuel jet injected into the surrounding high temperature combustion air. The fuel jet exit Reynolds number was 63. Several measurements were taken at different air preheats and fuel jet exit Reynolds number. The resulting hybrid color flame was found to be blue at the base of the flame followed by a yellow color flame. The length and width of flame during the entire free fall conditions has been examined. Also the relative flame length and width for blue and yellow portion of the flame has been examined under microgravity conditions. The results show that the flame length decreases and width increases with high air preheats in microgravity condition. In microgravity conditions the flame length is larger with normal temperature combustion air than high temperature air.

Ghaderi, M.; Gupta, A. K.

2003-01-01

146

Analysis of fuel vaporization, fuel/air mixing, and combustion in lean premixed/prevaporized combustors  

SciTech Connect

Requirements to reduce pollutant emissions from gas turbines used in aircraft propulsion and ground-based power generation have led to consideration of lean premixed/prevaporized (LPP) combustion concepts. This paper describes a series of the LPP combustor analyses performed with KIVA-II, a multi-dimensional CFD code for problems involving sprays, turbulence, and combustion. Modifications to KIVA-II`s boundary condition and chemistry treatments have been made to meet the needs of the present study. The study examines the relationships between fuel vaporization, fuel/air mixing, and combustion in a generic LPP combustor. Parameters considered include: mixer tube diameter, mixer tube length, mixer tube configuration (straight versus converging/diverging tubes), 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 have been 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.

Deur, J.M. [NYMA, Inc., Brook Park, OH (United States); Penko, P.F. [National Aeronautics and Space Administration, Cleveland, OH (United States). Lewis Research Center; Cline, M.C. [Los Alamos National Lab., NM (United States)

1995-07-01

147

Indoor air quality and ventilation strategies in the use of combustion space heating appliances in housing.  

PubMed

Indoor air quality (IAQ) in the use of combustion appliances is important for adequate evaluation of air pollution health risks. Since people spend most of their time inside buildings, especially the elderly and children, their exposure to indoor air contaminants can increase health problems in the community. Combustion materials emitted from combustion space heating appliances in housing during the winter may become a serious problem to health, since sources of ventilation are usually left closed to obtain a comfortable temperature level. To evaluate the IAQ and factors that may decrease combustion materials emitted from heaters, a study was done by using a house exposure model. The study found that IAQ in an unventilated house during combustion heater use was poor due to lack of fresh air. When using a heater, natural ventilation should be used to dilute air contaminants emitted from the heater. A concentration of carbon dioxide at about 1000 ppm and a comfortable temperature of 20 degrees C could be maintained by applying natural ventilation of about 0.12 m2 during the use of an unvented kerosene space heater. However, ventilation also depends on the number of the occupants and the wind velocity. The use of a steamer is also important to provide optimum humidity levels without elevating the respirable dust concentration above the acceptable limit. PMID:7883582

Setiani, O

1994-12-01

148

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

149

Apparatus for controlling fuel injection and swirl motion of air in internal combustion engine  

SciTech Connect

A fuel-injected internal combustion engine is described, comprising: a fuel injection valve disposed in an intake passage which communicates with a combustion chamber by way of an intake valve; a spark generating means disposed at an upper portion of the combustion chamber above a piston; a swirl controlling device for controlling a swirling motion to be given to intake air in the circumferential direction of the cylinder forming the combustion chamber; a control device which, at least at low load, controls the fuel injection valve to inject fuel; and a correction means for overriding the control device when the engine is cold for controlling the fuel injection valve to start fuel injection before the intake valve is opened and for controlling the swirl controlling device to suppress production of swirling motion of intake air.

Hatsoka, K.; Yamashita, A.; Misumi, M.; Hashimoto, N.

1989-03-07

150

Numerical simulation of high temperature air combustion in aluminum hydroxide gas suspension calcinations  

Microsoft Academic Search

The high temperature air combustion(HiTAC) process in gas suspension calcinations(GSC) was studied by using a CFD software FLUENT that can simulate the three-dimensional physical model of GSC with the k-epsilon turbulent viscous model, PDF non-premixed combustion species model, P1 radiation model, thermal and prompt NO pollution model. The simulation vividly describes the distributions of the temperature, velocity and consistency fields.

Dai-fei LIU; Feng-qi DING; Hong-liang ZHANG; Wen-bo ZHENG

2009-01-01

151

An Instability of Diluted Lean Methane\\/Air Combustion: Modeling and Control  

Microsoft Academic Search

In order to study possibilities of Model Predictive Control (MPC) to low temperature combustion, the authors performed a numerical study of combustion with a lean highly diluted methane\\/air mixture in a perfectly stirred reactor using a detailed chemical kinetic model. Chosen conditions are the following: equivalence ratio 0.6, residence time of mixture in reactor 0.5 s; molar fraction of Nitrogen 0.9,

T. Wada; F. Jarmolowitz; D. Abel; N. Peters

2010-01-01

152

Retene-a molecular marker of wood combustion in ambient air  

Microsoft Academic Search

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

Thomas Ramdahl

1983-01-01

153

Combustion of premixed fuel and air downstream of a plane sudden-expansion  

Microsoft Academic Search

Experiments have been performed to quantify the isothermal and combusting flows downstream of a plane sudden-expansion. The\\u000a detailed measurements correspond to an area expansion ratio of 2.86 and a Reynolds number of 20000, and the combusting flows\\u000a comprised premixed methane and air over a range of equivalence ratios with emphasis on values of 0.72 and 0.92 which gave\\u000a rise to

L. Khezzar; S. R. N. De Zilwa; J. H. Whitelaw

1999-01-01

154

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

155

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

Microsoft Academic Search

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

S. Gordon

1982-01-01

156

[Experimental investigation on plasma assistant combustion actuator in argon/air].  

PubMed

In order to obtain the characteristics of argon/air plasma assistant combustion actuators, experiments of three different actuators with normal, paratactic and meshy electrode configurations were respectively performed in argon/air mixture firstly, the results showed that the shape of electrode has little influence on the discharge characteristics. Then normal electrode was applied to study spectrum and discharge characteristics under the condition of 100% air and 10% argon/90% air. The comparison showed that, though in mixture the law of discharge characteristic was the same as that of pure air, discharge current and emission spectrum were strengthened, and initial discharge voltage reduced from 27 to 24 kV. PMID:22512154

Du, Hong-liang; He, Li-ming; Ding, Wei; Zhao, Bing-bing; Wang, Feng

2012-02-01

157

EXHAUST GAS RECIRCULATION EFFECTS ON HYDROGEN-AIR COMBUSTION  

Microsoft Academic Search

The effects of residence and micro mixing time scales on NOx formation in hydrogen combustion are modeled, using idealized Partially Stirred Reactors (PaSR), with stochastic Monte-Carlo simulations. The explicit dependence on residence and mixing time scales, of the mean and variance of mixture fraction, is derived and verified via the simulations. Transient responses of temperature and species mass fractions are

P. PRASAD; S. MAHALINGAM

2007-01-01

158

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

159

Calculated Adiabatic Combustion Temperatures of Hydrocarbon-Air Mixtures.  

National Technical Information Service (NTIS)

Manually calculated values of adiabatic combustion temperature are presented, using a slightly modified version of Penner's method, for the simple cases of nondissociation, and of dissociation to CO, H2 and O2 only, for a wide range of gaseous-phase hydro...

E. M. Goodger

1974-01-01

160

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 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

161

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

NASA Astrophysics Data System (ADS)

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 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.

1993-06-01

162

Combustion engine having fuel cut-off at idle speed and compressed air starting and method of operation  

Microsoft Academic Search

This patent describes a non-idle method of operating an internal combustion engine including a rotary engine shaft; fuel supply means to supply fuel to the engine to cause the operation of the engine; an air compressor driven by rotation of the shaft and communicating with the engine to supply compressed air thereto for mixing with fuel to form a combustible

Slaughter

1988-01-01

163

Comparative evaluation of gas-turbine engine combustion chamber starting and stalling characteristics for mechanical and air-injection  

NASA Technical Reports Server (NTRS)

The effectiveness of propellant atomization with and without air injection in the combustion chamber nozzle of a gas turbine engine is studied. Test show that the startup and burning performance of these combustion chambers can be improved by using an injection during the mechanical propellant atomization process. It is shown that the operational range of combustion chambers can be extended to poorer propellant mixtures by combined air injection mechanical atomization of the propellant.

Dyatlov, I. N.

1983-01-01

164

Combined air and fuel nozzle for fluidized bed combustion chamber  

SciTech Connect

A combined nozzle for air and fuel to a fluidized bed comprises two fixed portions mounted at the top and bottom of an air chamber and a movable, withdrawable portion which connects the two fixed portions and is guided by them. The movable portion blocks the lower fixed portion outwardly and conducts air and fuel to the upper fixed portion . Further , there is a device (3, 26) for sealing the lower fixed portion when the movable portion is removed for inspection during operation. (Fig. 2).

Bergkvist, J.

1981-10-06

165

Thermodynamic analysis of a seeded magnetogasdynamic combustion plasma  

NASA Astrophysics Data System (ADS)

A Faraday type magnetogasdynamic (MGD) seeded combustion gas plasma generated by burning fuel gas in air with up to 50 percent oxygen enrichment in stoichiometric ratio to determine the sources of thermodynamic irreversibility has been studied. For preliminary determination of the adiabatic flame temperature at one bar, five different fuel gases are studied, out of which four are derivatives of coal: water gas, Lurgi gas, Koppers-Totzek gas, producer gas, and methane. As seed, cesium, potassium and sodium in seed to fuel gas mass ratio of 0.01 to 0.03 in appropriate compound form are used and the equilibrium composition is calculated at 1 bar and temperature from 1500 to 3000 K by considering 14 species in the mixture. Subsequently, a Mollier enthalpy-entropy chart is produced for water gas burning with 50 percent oxygen enriched air and one percent potassium seed to fuel gas mass ratio in the above temperature range and in the pressure range of 0.01 to 100 bars. Finally, from the thermodynamic analysis it is shown that the electrical power generation per unit length is more and irreversibility due to the ohmic heating is less if the temperature is high.

Bose, T. K.

1986-06-01

166

Air fraction estimation for multiple combustion mode diesel engines with dual-loop EGR systems  

Microsoft Academic Search

This paper describes an innovative air fraction estimation method for diesel engines with dual-loop exhaust gas recirculation (EGR) systems to conduct multiple and alternative combustion modes for engine-out emission reduction. An observer is designed to estimate the air fractions in all the engine intake\\/exhaust sections using standard sensors equipped on the engine. The observer can provide indispensable information for the

Junmin Wang

2008-01-01

167

Combustion gas properties. Part 3: Hydrogen gas fuel and dry air  

NASA Technical Reports Server (NTRS)

A series of computations has been made to produce the equilibrium temperature and gas composition for hydrogen gas 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. Only sample tables and figures are provided in this report.

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

1985-01-01

168

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

169

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...

170

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

National Technical Information Service (NTIS)

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 viti...

G. L. Pellett C. Bruno W. Chinitz

2002-01-01

171

Mass air flow sensor diagnostics for adaptive fueling control of internal combustion engines  

Microsoft Academic Search

Presents an information synthesis (IS) approach for the mass air flow (MAF) sensor diagnosis on internal combustion engines. An information synthesis solution is attractive for diagnostics since the algorithm automatically calibrates itself, reduces the number of false detections and compresses a large amount of engine health information into the model coefficients. There are three primary parts to information synthesis diagnostics.

Patrick J. Buehler; Matthew A. Franchek; I. Makki

2002-01-01

172

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 ...

173

Analysis of combustion turbine inlet air cooling systems applied to an operating cogeneration power plant  

Microsoft Academic Search

In this work, combustion turbine inlet air cooling (CTIAC) systems are analyzed from an economic outlook, their effects on the global performance parameters and the economic results of the power plant. The study has been carried out on a combined cogeneration system, composed of a General Electric PG 6541 gas turbine and a heat recovery steam generator. The work has

R. Chacartegui; F. Jiménez-Espadafor; D. Sánchez; T. Sánchez

2008-01-01

174

Particle combustion rates in premixed flames of polydisperse metal—air aerosols  

Microsoft Academic Search

A new approach and experimental technique are proposed to determine times of metal particle combustion in flames of polydisperse aerosols. Laminar flames are produced in air at 1 atm, using aerosol jets formed by an electrostatic particulate method. The flame radiation intensities as a function of vertical coordinate are measured and compared with the flame radiation profiles reconstructed using experimental

Y. Shoshin; E. Dreizin

2003-01-01

175

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...

176

Hazardous Air Pollutants from the Combustion of an Emulsified Heavy Fuel Oil in a Firetube Boiler.  

National Technical Information Service (NTIS)

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 determinin...

C. A. Miller

1996-01-01

177

Control of air toxin particulate and vapor emissions after coal combustion utilizing calcium magnesium acetate  

Microsoft Academic Search

Major environmental issues are now coming to the forefront in all parts of the globe with increased public awareness of the human health effects and the possible effects on our global environment. Modern control technologies, when implemented, have significantly reduced air pollution emissions that are a result of coal combustion during this century. However, the emissions have not been completely

Judith Irene Shuckerow; Judith Anne Steciak; Donald L. Wise; Yiannis A. Levendis; Girard A. Simons; Joseph D. Gresser; Edgar B. Gutoff; C. David Livengood

1996-01-01

178

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

179

Method and apparatus for regulating the fuel-air ratio in internal combustion engines  

Microsoft Academic Search

A method and an apparatus for regulating the fuel-air ratio of the operational mixture of an internal combustion engine and for monitoring the operational readiness of a lambda sensor controlling the regulating apparatus and functioning according to the principle of ionic conduction in fixed electrolytes. A constant reference voltage which approximately corresponds to the average sensor output voltage is connected

U. Drews; W. Mohrle; P. Werner

1982-01-01

180

Device for regulating the fuel-air ratio in internal combustion engines  

Microsoft Academic Search

A device is proposed for regulating the fuel-air ratio in the operating mixture of an internal combustion engine and for monitoring the operational readiness of a lambda sensor controlling the regulating device and functioning by the principle of ion conduction in solid electrolytes. The lambda sensor has an adjustable, constant reference voltage switched opposite to it. The reference voltage approximately

U. Drews; W. Mohrle; P. Werner

1983-01-01

181

Radiation damage studies on MCz and standard and oxygen enriched epitaxial silicon devices  

NASA Astrophysics Data System (ADS)

N-type epitaxial layers of 72 ?m thickness and a resistivity of 150 ? cm have been grown on highly Sb-doped Cz-substrates at ITME (Warsaw). The diode processing was performed at CiS-Erfurt. For comparison a batch of 280 ?m thick n-type MCz wafers with a resistivity of >600 ? cm from Okmetic (Finland) was added to the process run. Depth profiles of the oxygen and carbon concentration were measured via the SIMS-method on as grown epi-layers and after different device-process steps at CiS including an oxygen enrichment at 1100 °C for 24 h. For the MCz material the profiles were measured on untreated samples and after the full device process. Irradiation runs were performed with neutrons at the TRIGA reactor of Ljubljana up to a fluence value of 10 16 cm -2. The development of the macroscopic device parameters (effective doping concentration and charge collection for ?-particles) as function of fluence is presented for the standard and oxygenated epi-devices and compared with the MCz-diodes. The results are discussed in the frame of defect studies resulting from TSC-measurements.

Fretwurst, E.; Hönniger, F.; Kramberger, G.; Lindström, G.; Pintilie, I.; Röder, R.

2007-12-01

182

Oxygen enrichment and its application to life support systems for workers in high-altitude areas.  

PubMed

Background: Workers coming from lowland regions are at risk of developing acute mountain sickness (AMS) when working in low oxygen high-altitude areas. Objectives: The aim of this study was to improve the conditions that lead to hypoxia and ensure the safety of the high-altitude workers. We analyzed the influence of low atmospheric pressure on the oxygen enrichment process in high-altitude areas using an engineering method called low-pressure swing adsorption (LPSA). Methods: Fourteen male subjects were screened and divided into three groups by type of oxygen supply system used: (1) oxygen cylinder group; (2) LPSA oxygen dispersal group; and (3) control group. These tests included arterial oxygen saturation (SaO2), pulse rate (PR), breaths per minute (BPM), and blood pressure (BP). Results: The results showed that after supplying oxygen using the LPSA method at the tunnel face, the SaO2 of workers increased; the incidence of acute mountain sickness, PR, and BPM significantly decreased. Conclusions: The LPSA life support system was found to be a simple, convenient, efficient, reliable, and applicable approach to ensure proper working conditions at construction sites in high-altitude areas. PMID:25000108

Li, Yongling; Liu, Yingshu

2014-07-01

183

An Elementary Overview of the Selection of Materials for Service in Oxygen-Enriched Environments  

NASA Technical Reports Server (NTRS)

The process for selecting materials for use in oxygen or oxygen-enriched environments is one that continues to be investigated by many industries due to the importance to those industries of oxygen systems. There are several excellent resources available to assist oxygen systems design engineers and end-users, with the most comprehensive being ASTM MNL-36, Safe Use of Oxygen and Oxygen Systems: Handbook for Design, Operation and Maintenance, 2nd Edition. ASTM also makes available several standards for oxygen systems. However, the ASTM publications are extremely detailed, and typically designed for professionals who already possess a working knowledge of oxygen systems. No notable resource exists, whether an ASTM or other organizational publication, which can be used to educate engineers or technicians who have no prior knowledge of the nuances of oxygen system design and safety. This paper will fill the void for information needed by organizations that design or operate oxygen systems. The information in this paper is not new information, but is a concise and easily understood summary of selecting materials for oxygen systems. This paper will serve well as an employee s first introduction to oxygen system materials selection, and probably the employee s first introduction to ASTM.

Davis, Samuel Eddie

2012-01-01

184

Air\\/fuel ratio control system having function of controlling supply of secondary air into intake pipe of internal combustion engine  

Microsoft Academic Search

An air\\/fuel ratio control system is disclosed for performing feedback control of the air\\/fuel ratio of an air\\/fuel mixture being supplied to an internal combustion engine in response to the concentration of an exhaust gas ingredient. The air\\/fuel ratio control system includes a device for controlling a shot air valve for supplying secondary air into the intake pipe of the

K. Otsuka; S. Hasegawa; S. Narasaka

1983-01-01

185

Copper contamination effects on hydrogen-air combustion under SCRAMJET (supersonic combustion ramjet) testing conditions  

SciTech Connect

Two forms of copper catalytic reactions (homogeneous and heterogeneous) in hydrogen flames were found in a literature survey. Hydrogen atoms in flames recombine into hydrogen molecules through catalytic reactions, and these reactions which affect the timing of the combustion process. Simulations of hydrogen flames with copper contamination were conducted by using a modified general chemical kinetics program (GCKP). Results show that reaction times of hydrogen flames are shortened by copper catalytic reactions, but ignition times are relatively insensitive to the reactions. The reduction of reaction time depends on the copper concentration, copper phase, particle size (if copper is in the condensed phase), and initial temperature and pressure. The higher the copper concentration of the smaller the particle, the larger the reduction in reaction time. For a supersonic hydrogen flame (Mach number = 4.4) contaminated with 200 ppm of gaseous copper species, the calculated reaction times are reduced by about 9%. Similar reductions in reaction time are also computed for heterogeneous copper contamination. Under scramjet testing conditions, the change of combustion timing appears to be tolerable (less than 5%) if the Mach number is lower than 3 or the copper contamination is less than 100 ppm. The higher rate the Mach number, the longer the reaction time and the larger the copper catalytic effects. 7 tabs., 8 figs., 34 refs.

Chang, S.L.; Lottes, S.A.; Berry, G.F.

1990-01-01

186

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

187

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

188

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...

189

Air pollution and lung cancer: diesel exhaust, coal combustion  

Microsoft Academic Search

It is known, that cigarette smoking is by far the most important cause of lung cancer and that about a dozen occupational exposures are also established as causes of this disease. There has been continuing uncertainty about the role of general air pollution. During the past few years, this uncertainty has been compounded with anxiety that the increasing use of

Ian T. T. Higgins

1984-01-01

190

Utilization of ventilation air methane as a supplementary fuel at a circulating fluidized bed combustion boiler.  

PubMed

Ventilation air methane (VAM) accounts for 60-80% of the total emissions from coal mining activities in China, which is of serious greenhouse gas concerns as well as a waste of valuable fuel sources. This contribution evaluates the use of the VAM utilization methods as a supplementary fuel at a circulating fluidized bed combustion boiler. The paper describes the system design and discusses some potential technical challenges such as methane oxidation rate, corrosion, and efficiency. Laboratory experimentation has shown that the VAM can be burnt completely in circulated fluidized bed furnaces, and the VAM oxidation does not obviously affect the boiler operation when the methane concentration is less than 0.6%. The VAM decreased the incomplete combustion loss for the circulating fluidized bed combustion furnace. The economic benefit from the coal saving insures that the proposed system is more economically feasible. PMID:18505001

You, Changfu; Xu, Xuchang

2008-04-01

191

Premixed CH4/O2-enriched air combustion: Identification of thermal, chemical and aerodynamic effects  

NASA Astrophysics Data System (ADS)

This work contributes to the evaluation of a new innovative process focused on the reduction of the cost of a post-combustion capture of CO2 in a Carbon Capture and Storage system (CCS). The process based on the separation of dried fumes composed mainly by CO2 and N2 by using membranes, which should lead to a lower energetic separation cost than amines. But the membranes become efficient if the upstream CO2 concentration is higher than 30% at their entrance that requires enriching the oxidizer flow by O2. To maintain the exhaust temperature compatible with materials thermal resistance, the reactants are diluted by a recirculation of a part of the flue gases (like N2/O2/CO2). But, the chemical kinetic, the energetic efficiencies, the radiation transfer, the transport and thermal properties of the flow can be affected by CO2. The objective of this work will be to identify the behaviour of the combustion of premixed CH4/O2-enriched air, both diluted in N2 and CO2 and to determine the combustion parameters. This allows to recover the CH4/air conditions in terms of CO2 concentration in reactants, O2 excess, dilution rate, temperature of the reactants, etc. Experiments are performed on the laminar premixed flame using counterflow burner. To characterize the combustion behaviour, the flammability limits are determined and flame thickness and position are measured from PLIF-OH diagnostic. Further, CHEMKIN simulations are performed to check the validity of the GRI3.0 chemical kinetic mechanism for premixed CH4/air synthetic combustion and identify the leading phenomena.

Most, J.-M.; Dahikar, S.; Pal, S.; Claverie, A.; Denis, D.; Pillier, L.; de Persis, S.

2012-11-01

192

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

193

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

NASA Astrophysics Data System (ADS)

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.

1993-06-01

194

Numerical Simulation of Turbulent Propane-Air Combustion with Non-Homogeneous Reactants  

Microsoft Academic Search

Two-dimensional numerical simulations of turbulent propane-air combustion have been performed including complex chemistry and realistic molecular transport. The aerothermochemical conditions simulated (reactant temperature and pressure, turbulence rms velocity and integral length scale) correspond to conditions at the time of ignition in an automotive gasoline direct-injection reciprocating IC engine at low speed and light load. Both stoichiometric homogeneous reactants and non-homogeneous

D. Haworth; B. Cuenot; T. Poinsot; R. Blint

1998-01-01

195

Diluted Air Combustion and NOx Emission in a HiTAC Furnace  

Microsoft Academic Search

CFD modeling of NOx emission via N2O-intermediate mechanism was developed to predict the NOx formation in an experimental furnace equipped with high temperature air combustion (HiTAC) system. The good agreement between the predicted and measured results illustrates the superiority of using a N2O-intermediate model in prediction of NOx emission during low peak temperature, which happens in HiTAC systems. Moreover, the

Abbas Khoshhal; Masoud Rahimi; Ammar Abdulaziz Alsairafi

2011-01-01

196

Experimental study on premixed combustion of spherically propagating methanol-air-nitrogen flames  

Microsoft Academic Search

The outward propagation and development of surface instability of the spark-ignited spherical premixed flames for methanol-air-nitrogen\\u000a mixtures were experimentally studied by using a constant volume combustion chamber and a high-speed schlieren photography\\u000a system. The laminar burning velocities, the mass burning fluxes, and the Markstein lengths were obtained at different equivalence\\u000a ratios, dilution ratios, initial temperatures, and pressures. The laminar burning

Xiangang Wang; Zhiyuan Zhang; Zuohua Huang; Xibin Wang; Haiyan Miao

2010-01-01

197

Unique, clean-air, continuous-flow, high-stagnation-temperature facility for supersonic combustion research  

NASA Technical Reports Server (NTRS)

Accurate, spatially-resolved measurements can be conducted of a model supersonic combustor in a clean air/continuous flow supersonic combustion facility whose long run times will allow not only the point-by-point mapping of flow field variables with laser diagnostics but facilitate the simulation of steady-state combustor conditions. The facility will provide a Mach 2 freestream with static pressures in the 1 to 1/6 atm range, and stagnation temperatures of up to 2000 K.

Krauss, R. H.; Mcdaniel, J. C., Jr.; Scott, J. E., Jr.; Whitehurst, R. B., III; Segal, C.

1988-01-01

198

Influences of pressure on reduced-gravity combustion of HAN–methanol–water droplets in air  

Microsoft Academic Search

Reduced-gravity experiments were performed to investigate combustion characteristics of individual monopropellant droplets composed of hydroxylammonium nitrate (HAN), methanol, and water. The experiments were conducted using the 2.2 Second Drop Tower at the NASA John Glenn Research Center at Lewis Field in Cleveland, OH. Gravitational levels were about 10?4 times normal gravity and experiments were performed in air at about 25?°C

J. B. Wei; B. D. Shaw

2006-01-01

199

Particle combustion rates for mechanically alloyed Al–Ti and aluminum powders burning in air  

Microsoft Academic Search

Mechanically alloyed aluminum-rich powders of Al–Ti (10, 15, 20, and 25 atom% of Ti) were produced and their combustion was compared to that of aluminum and titanium powders of comparable sizes. A laminar lifted-flame aerosol burner developed recently was used in this research. The aerosols were produced and burned in air. Measured flame speeds were higher for the aerosols of

Yuriy L. Shoshin; Edward L. Dreizin

2006-01-01

200

HMX flame structure for combustion in air at a pressure of 1 atm  

Microsoft Academic Search

The chemical structure of HMX flame during combustion in air at a pressure of 1 atm was calculated using molecular beam mass\\u000a spectrometric sampling. HMX vapor was recorded for the first time near the burning surface. A total of 11 species were identified\\u000a in the HMX flame (H2, H2O, HCN, N2, CO, CH2O, NO, N2O, CO2, NO2, and HMX vapor),

A. A. Paletsky; E. N. Volkov; O. P. Korobeinichev

2008-01-01

201

Combustion generated instabilities in a hydrocarbon-air planar mixing layer  

Microsoft Academic Search

The effects of combustion with high heat release on the initial instabilities of a mixing layer were investigated experimentally in a two-stream planar mixing layer with hydrocarbon fuels. Experiments were performed with non-premixed reactants under two distinct conditions where the lean reactant (air) was placed in either the high-speed (AHS) or low-speed stream (FHS) such that the location of heat

Lyle M. Pickett; Jaal B. Ghandhi

2002-01-01

202

Using Neural Networks for Air-to-Fuel Ratio Estimation in Two Stroke Combustion Engines  

Microsoft Academic Search

To be able to meet the demands of tomorrow on lower emissions from small two-stroke en- gines, used e.g. in chain-saws, there is a need to enhance the control over the combustion. One interesting parameter is the air-to-fuel ratio (A\\/F). If A\\/F can be measured, then it is possible to intelligently control the fuel, and thus obtain a desired A\\/F.

Arne Linde; Mikael Taveniku; Bertil Svensson

1995-01-01

203

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

204

Thermodynamic and transport combustion properties of hydrocarbons with air. Part 4: Compositions corresponding to Rankine temperature schedules in part 3  

NASA Technical Reports Server (NTRS)

The equilibrium compositions corresponding to the thermodynamic and transport combustion properties for a wide range of conditions for the reaction of hydrocarbons with air are presented. The compositions presented correspond to Rankine temperature schedules.

Gordon, S.

1982-01-01

205

Gas Turbine Cycle Calculations: Thermodynamic Data Tables for Air and Combustion Products for Three Systems of Units.  

National Technical Information Service (NTIS)

In performing rigorous calculations involving the thermodynamic properties of air and combustion products, as encountered in open cycle gas turbines, the data tabulations of Fielding and Topps are widely used. These tables consist of specific heat, enthal...

M. S. Chappel E. P. Cockshutt

1974-01-01

206

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

SciTech Connect

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, K.L.

1980-12-30

207

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

208

Effect of excess air on the optimization of heating appliances for biomass combustion  

SciTech Connect

The performance of a domestic appliance for wood logs combustion is a function of several variables, such as the geometric design of the appliance and its operating parameters. Among them, air feeding conditions are really decisive if the objective function is the maximization of the heat recovered from flue gases. Therefore, even if pollutant emissions have to be ever considered, the amount of excess air can be seen as a fundamental parameter in the definition of thermal efficiency of the appliance. In this paper the role of this parameter is analysed. The analysis is conducted by linking the results obtained from experimental data, detailed CFD simulations and a simplified mathematical model based on a network of CSTR. The derivation of an idealized schematization of the appliance was essential to realize the role of excess air variations, with more generality than with respect to a specific appliance configuration. Conversely, while the experimental data and CFD results were necessary to derive the simplified model, the indications given by this simplified model were useful to analyze results coming from both experiments and detailed numerical simulations. It has been evidenced the need to distinguish between the role of excess air in the chemical combustion and in the heat recovery in the appliance as well as to quantify the feedback between these two processes. (author)

Menghini, D. [Dipartimento di Ingegneria Chimica, Universita degli studi di Napoli Federico II, Piazzale Tecchio 80, 80125 Napoli (Italy); Marra, F.S.; Allouis, C.; Beretta, F. [Consiglio Nazionale delle Ricerche, Istituto di Ricerche sulla Combustione - CNR, via Diocleziano 328, 80124 Napoli (Italy)

2008-07-15

209

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

210

Turbulent mixing and combustion in 2-dimensional counter shear methane-air flow  

NASA Astrophysics Data System (ADS)

As a first step to analyze the combustion phenomena within a natural gas engine, a 2D numerical analysis of turbulent diffusion combustion with methane as the fuel and air as the oxidizer was performed, focusing on: the turbulent enhancement of mixing and combustion, the influence of heat release on mixing, the generation of pollutants, the efficiency of combustion, and the dependency of the observed interesting phenomena on the flow parameters like Reynolds number. The computational domain is a square surrounded by thermally adiabatic and free-slip boundaries, and flux-periodic boundaries. Each of nitrogen-diluted methane and nitrogen-diluted oxygen is injected with each Reynolds number from each periodic boundary to the opposite direction, where the upper right-going high-temperature methane and nitrogen flow and the lower left-going high-temperature oxygen and nitrogen flow interact and get mixed due to viscosity and diffusivity. The resulting counter shear flow forms a turbulent diffusion flame after ignition. The effect of the heat release on the vortex formation, time evolution of chemical reaction products, and the interaction mechanism of the species distribution and vortex structure were analyzed qualitatively.

Umeda, Yoshito; Fujiwara, Toshi

211

Combustion  

NASA Astrophysics Data System (ADS)

The process whereby a substance is combined with oxygen with the production of heat. Burning is a familiar example of this process. The energy required to propel chemical rockets is provided by the combustion of fuel with an oxidant at very high temperatures. A common oxidant is liquid oxygen (often denoted by LOX). Others include hydrogen peroxide and nitrogen tetroxide....

Murdin, P.

2000-11-01

212

The effect of fuel and air agitation on the combustion process in a low-emission combustion chamber  

NASA Astrophysics Data System (ADS)

Methods for numerically simulating the working process in low-emission combustion chamber and for testing it are described. A method of using numerical simulation for predicting NO x emission and combustion process stability in a low-emission combustion chamber is proposed.

Bulysova, L. A.; Gorban', V. D.

2013-09-01

213

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

214

Theoretical studies of the ignition and combustion of silane-hydrogen-air mixtures  

NASA Technical Reports Server (NTRS)

A chemical kinetic mechanism is proposed for the combustion of silane-hydrogen-oxygen-nitrogen mixtures in the initial temperature range from 800K to 1250K and pressure range from 0.5 to 1.35 atm. The mechanism yields results which are in agreement with published ignition delay times obtained from shock tube experiments. Comparisons between the results obtained using the proposed mechanism and that of an alternative mechanism reveal that the former predicts appreciably shorter ignition delay times, but a flame blowout envelope which is shifted so as to decrease the stable flame region. Over much of the thermodynamic range examined, the mechanism predicts long reaction times. A three step global mechanism is proposed which closely models the ignition phase of SiH4 - H2 - air combustion; however, the reaction phase is less well reproduced by the global model. The necessity for additional experimental data to further assess the proposed models is stressed.

Chinitz, W.

1985-01-01

215

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.

216

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

217

Air Fractionation by Adsorption  

Microsoft Academic Search

Pressure swing adsorption (PSA) processes for air separation differ by the modes and conditions of operation of the adsorption, the desorption, and the complementary steps, as well as by the types of adsorbents used. Three commercial PSA processes for air separation are reviewed and compared. The first process uses a zeolitic adsorbent and produces only an oxygen-enriched product gas. The

Shivaji Sircar

1988-01-01

218

Air fractionation by adsorption  

Microsoft Academic Search

Pressure swing adsorption (PSA) processes for air separation differ by the modes and conditions of operation of the adsorption, the desorption, and the complementary steps, as well as by the types of adsorbents used. Three commercial PSA processes for air separation are reviewed and compared. The first process uses a zeolitic adsorbent and produces only an oxygen-enriched product gas. The

Sircar

2009-01-01

219

The composition of combustion products formed from gasoline-hydrogen-air mixtures in a constant-volume spherical chamber  

Microsoft Academic Search

The experimental unit, procedure for testing, and the results and reliability of the determination of the composition of combustion\\u000a products formed from gasoline-hydrogen-air (containing 0–100% hydrogen), gasoline-air, and isooctane-hydrogen-air mixtures\\u000a in a constant-volume chamber are described. Studies were performed at initial mixture temperatures of 20–70°C and a 0.1 MPa\\u000a pressure.

L. N. Bortnikov; D. A. Pavlov; M. M. Rusakov; A. P. Shaikin

2011-01-01

220

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

221

Air pollution combustion emissions: Characterization of causative agents and mechanisms associated with cancer, reproductive, and cardiovascular effects  

Microsoft Academic Search

Combustion emissions account for over half of the fine particle (PM2.5) air pollution and most of the primary particulate organic matter. Human exposure to combustion emissions including the associated airborne fine particles and mutagenic and carcinogenic constituents (e.g., polycyclic aromatic compounds (PAC), nitro-PAC) have been studied in populations in Europe, America, Asia, and increasingly in third-world counties. Bioassay-directed fractionation studies

Joellen Lewtas

2007-01-01

222

Review of the PDWA Concept for Combustion Enhancement in a Supersonic Air-Breathing Combustor Environment  

NASA Technical Reports Server (NTRS)

This paper reviews the design of the Pulsed Detonation Wave Augmentor (PDWA) concept and the preliminary computational fluid dynamics studies that supported it. The PDWA relies on the rapid generation of detonation waves in a small tube, which are then injected into the supersonic stream of the main combustor. The blast waves thus generated are used to stimulate the mixing and combustion inside the main combustor. The mixing enhancement relies on various forms of the baroclinic interaction, where misaligned pressure and density gradients combine to produce vortical flow. By using unsteady shock waves, the concept also uses the Richtmyer-Meshkov effect to further increase the rate of mixing. By carefully designing the respective configurations of the combustor and the detonation tubes, one can also increase the penetration of the fuel into the supersonic air stream. The unsteady shocks produce lower stagnation pressure losses than steady shocks. Combustion enhancement can also be obtained through the transient shock-heating of the fuel-air interface, and the lowering of the ignition delay in these regions. The numerical simulations identify these processes, and show which configurations give the best results. Engineering considerations are also presented, and discuss the feasibility of the concept. Of primary importance are the enhancements in performance, the design simplicity, the minimization of the power, cost, and weight, and the methods to achieve very rapid cycling.

Canbier, Jean-Luc; Edwards, Thomas A. (Technical Monitor)

1995-01-01

223

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

224

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

225

Advancing lean combustion of hydrogen–air mixtures by laser-induced spark ignition  

Microsoft Academic Search

We investigate how ignition through laser-induced plasma can improve the application of lean combustion, in particular in environmental conditions relevant to hydrogen internal combustion engines (ICE). Major design goals when developing combustion engines are increasing thermal efficiency and decreasing combustion emissions. High compression ratios, lean combustion and precise ignition timings are contributing factors in ICE optimization. In our studies, several

Dietmar Böker; Dieter Brüggemann

2011-01-01

226

Promoted Combustion Test Data Re-Examined  

NASA Technical Reports Server (NTRS)

Promoted combustion testing of metallic materials has been performed by NASA since the mid-1980s to determine the burn resistance of materials in oxygen-enriched environments. As the technolo gy has advanced, the method of interpreting, presenting, and applying the promoted combustion data has advanced as well. Recently NASA changed the bum criterion from 15 cm (6 in.) to 3 cm (1.2 in.). This new burn criterion was adopted for ASTM G 124, Standard Test Method for Determining the Combustion Behavior- of Metallic Materials in Oxygen-Enriched Atmospheres. Its effect on the test data and the latest method to display the test data will be discussed. Two specific examples that illustrate how this new criterion affects the burn/no-bum thresholds of metal alloys will also be presented.

Lewis, Michelle; Jeffers, Nathan; Stoltzfus, Joel

2010-01-01

227

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

228

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

229

Detonation Cell Size Measurements in High-Temperature Hydrogen-Air-Steam Mixtures at the BNL High-Temperature Combustion Facility.  

National Technical Information Service (NTIS)

The High-Temperature Combustion Facility (HTCF) was designed and constructed with the objective of studying detonation phenomena in mixtures of hydrogen-air-steam at initially high temperatures. Cell size measurements have shown that for any hydrogen-air-...

G. Ciccarelli T. Ginsberg J. L. Boccio C. Finfrock L. Gerlach H. Tagawa A. Malliakos

1997-01-01

230

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

231

Fluidized-bed combustion: Air pollution analyses. November 1970-March 1990 (A Bibliography from the NTIS data base). Report for November 1970-March 1990  

SciTech Connect

This bibliography contains citations concerning research of air-pollution conditions attributable to the operation of fluidized-bed combustion systems. Analyses and studies of combustion processes, emissions, environmental impact, and cost summaries are provided. Air-pollution-abatement and mechanical/chemical processes are described in separate bibliographies. (Contains 310 citations fully indexed and including a title list.)

Not Available

1990-03-01

232

Fluidized-bed combustion: Air-pollution abatement. September 1972-March 1990 (A Bibliography from the NTIS data base). Report for September 1972-March 1990  

SciTech Connect

This bibliography contains citations concerning the abatement of air-pollution environments attributable to the operation of fluidized-bed combustion systems. Analyses and studies of combustion processes, fuels, regulations, and control equipment are provided. Air-pollution control and mechanical/chemical processes are described in separate bibliographies. (Contains 87 citations fully indexed and including a title list.)

Not Available

1990-03-01

233

A novel microwave plasma combustor toward understanding plasma assisted ignition and plasma assisted combustion of methane/air mixtures  

NASA Astrophysics Data System (ADS)

A novel microwave plasma combustor has been developed to study mechanisms of plasma-assisted ignition (PAI) and plasma-assisted combustion (PAC). The system allows us to inject a 2.45 MHz atmospheric argon microwave plasma jet directly into a combustion reaction zone to investigate effects of PAI and PAC. Three distinct zones: a pure plasma zone, a plasma-combustion hybrid zone, and a combustion zone are investigated by optical emission spectroscopy (OES) and cavity ringdown spectroscopy (CRDS) of OH, etc. plasma and combustion intermediates. The experimental results allow us to understand the formation of OH radicals and roles of OH in PAI and PAC of methane-air mixtures in a wide range of fuel equivalence ratios ranging from rich to lean burn. A U-curve of plasma power versus fuel equivalence ratio in the PAI of methane-air mixtures is observed. The roles of OH in PAI and PAC of premixed methane-air flames around the flammability limit are discussed.

Wang, Chuji; Wu, Wei

2012-10-01

234

Partitioning of gas or oil furnaces and water heaters to reduce drafts. Final report. [Possible saving by way of less cold air infiltration if combustion air is drawn from outside  

Microsoft Academic Search

The goal of this experiment was to determine if energy could be saved by providing furnaces and water-heaters with ''make-up air'' (air for combustion) from outdoors, instead of drawing this air from inside the house. By not drawing air which has already been heated and humidified from the house, cold air infiltration through cracks in windows, doors and walls should

Goerz

1983-01-01

235

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

236

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

SciTech Connect

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 HO/sub 2/ 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, C.J.

1988-02-01

237

Numerical Simulation of Turbulent Propane-Air Combustion with Non-Homogeneous Reactants  

NASA Astrophysics Data System (ADS)

Two-dimensional numerical simulations of turbulent propane-air combustion have been performed including complex chemistry and realistic molecular transport. The aerothermochemical conditions simulated (reactant temperature and pressure, turbulence rms velocity and integral length scale) correspond to conditions at the time of ignition in an automotive gasoline direct-injection reciprocating IC engine at low speed and light load. Both stoichiometric homogeneous reactants and non-homogeneous reactants with fuel-based equivalence ratios ranging from zero to four have been simulated. In the case of non-homogeneous reactants, a primary premixed flame (defined based on disappearance of the propane fuel) is followed by a secondary heat-release zone that is dominated by CO kinetics and turbulent mixing. Beyond a few flame thicknesses behind the primary flame, any remaining fuel has been broken down into carbon monoxide and hydrogen. Quantitative information relevant for modeling turbulent flame propagation through nonhomogeneous reactants has been extracted.

Haworth, D.; Cuenot, B.; Poinsot, T.; Blint, R.

1998-11-01

238

Computations of spray, fuel-air mixing, and combustion in a lean-premixed-prevaporized combustor  

NASA Technical Reports Server (NTRS)

A code was developed for computing the multidimensional flow, spray, combustion, and pollutant formation inside gas turbine combustors. The code developed is based on a Lagrangian-Eulerian formulation and utilizes an implicit finite-volume method. The focus of this paper is on the spray part of the code (both formulation and algorithm), and a number of issues related to the computation of sprays and fuel-air mixing in a lean-premixed-prevaporized combustor. The issues addressed include: (1) how grid spacings affect the diffusion of evaporated fuel, and (2) how spurious modes can arise through modelling of the spray in the Lagrangian computations. An upwind interpolation scheme is proposed to account for some effects of grid spacing on the artificial diffusion of the evaporated fuel. Also, some guidelines are presented to minimize errors associated with the spurious modes.

Dasgupta, A.; Li, Z.; Shih, T. I.-P.; Kundu, K.; Deur, J. M.

1993-01-01

239

Heat transfer and pressure distributions on hemisphere-cylinders in methane-air combustion products at Mach 7  

NASA Technical Reports Server (NTRS)

Heat-transfer and pressure distributions were measured over the surfaces of three hemisphere-cylinder models tested at a nominal Mach number of 7 in the Langley 8-foot high-temperature structures tunnel which uses methane-air products of combustion as a test medium. The results showed that the heat-transfer and pressure distributions over the surface of the models were in good agreement with experimental data obtained in air and also with theoretical predictions.

Weinstein, I.

1973-01-01

240

Split engine operation of closed loop controlled multi-cylinder internal combustion engine with air-admission valve  

Microsoft Academic Search

Split engine operation of a closed loop controlled multicylinder internal combustion engine is effected by a charge forming device which comprises an induction system including a common chamber divided by a partition into a first sub-chamber and into a second sub-chamber and an air admission valve to permit or prevent admission of air into the second sub-chamber. The first sub-chamber

Iizuka

1980-01-01

241

Development of the Utilization of Combustible Gas Produced in Existing Sanitary Landfills. Investigation of Effects of Air Inclusion.  

National Technical Information Service (NTIS)

A combustible gas mixture composed of methane and carbon dioxide is generated in municipal solid waste landfills. A practical consequence of the collection of this fuel gas is the inclusion of some air in the collected product. This report discusses the e...

1981-01-01

242

Analysis of NO formation in high temperature diluted air combustion in a coaxial jet flame using an unsteady flamelet model  

Microsoft Academic Search

The high temperature diluted air combustion, which improves the flame stability while lowers the NO emission level, has been numerically investigated. The Favre-averaged Navier–Stokes equations are solved by a finite volume method of SIMPLE type that incorporates the laminar flamelet concept with the standard k–? turbulence model. The NO formation is estimated by solving the Eulerian particle transport equations in

K. W. Lee; D. H. Choi

2009-01-01

243

Development of the Utilization of Combustible Gas Produced in Existing Sanitary Landfills: Investigation of Effects of Air Inclusion.  

National Technical Information Service (NTIS)

A combustible gas mixture composed of methane and carbon dioxide is generated in municipal solid waste landfills. A practical consequence of the collection of this fuel gas is the inclusion of some air in the collected product. The effects of such include...

1983-01-01

244

Fuel data standardization study for JP-4, JP-5, JP-7, and RJ-5 combusted in air. Final report  

Microsoft Academic Search

This report summarizes a study conducted to standardize the fuel performance data used in the Ramjet and Laser Aerodynamics Division of the Air Force Aero Propulsion Laboratory. The NASA one-dimensional equilibrium (ODE) thermochemical computer program was used to generate the fuel combustion product properties contained in the tables and graphs in this report. Thermochemical equilibrium data (molecular weight, specific heat

1974-01-01

245

A comprehensive evaluation of the influence of air combustion and oxy-fuel combustion flue gas constituents on Hg(0) re-emission in WFGD systems.  

PubMed

This paper evaluates the influence of the main constituents of flue gases from coal combustion (CO2, O2, N2 and water vapor), in air and oxy-fuel combustion conditions on the re-emission of Hg(0) in wet scrubbers. It was observed that the concentration of water vapor does not affect the re-emission of mercury, whereas O2 and CO2 have a notable influence. High concentrations of O2 in the flue gas prevent the re-emission of Hg(0) due to the reaction of oxygen with the metals present in low oxidation states. High concentrations of CO2, which cause a decrease in the pH and the redox potential of gypsum slurries, reduce the amount of Hg(0) that is re-emitted. As a consequence, the high content of CO2 in oxy-fuel combustion may decrease the re-emission of Hg(0) due to the solubility of CO2 in the suspension and the decrease in the pH. It was also found that O2 affects the stabilization of Hg(2+) species in gypsum slurries. The results of this study confirm that the amount of metals present in limestone as well as the redox potential and pH of the slurries in wet desulphurization plants need to be strictly controlled to reduce Hg(0) re-emissions from power plants operating under oxy-fuel combustion conditions. PMID:24887118

Ochoa-González, Raquel; Díaz-Somoano, Mercedes; Martínez-Tarazona, M Rosa

2014-07-15

246

Combustion of high-sulfur coal and anthracite wastes in a rotary kiln combustor with an advanced internal air distributor  

SciTech Connect

Fluid bed combustors have received extensive testing with both high-sulfur coal and anthracite wastes. Rotary kilns are effective and popular devices for waste combustion. The Angelo Rotary Furnace{trademark} has been developed to improve the operation of rotary pyrolyzer/combustor systems through enhanced air distribution, which in this process is defined as staged, swirled combustion air injection. Fourteen of these new furnaces have been installed worldwide. Two units in Thailand, designed for rice hull feed with occasional lignite feed, have been recently started up. An older unit in Pennsylvania is being upgraded with a new, more advanced air distribution system for a series of tests this fall in which inexpensive high-sulfur coal and anthracite wastes will be fired with limestone. The purposes of these tests are to determine the burning characteristics of these two fuels in this system, to discover the Ca/S ratios necessary for operation of a rotary kiln combusting these fuels, and to observe the gas-borne emissions from the furnace. An extensive preliminary design study will be performed on a commercial installation for combustion of anthracite wastes. 14 refs., 5 figs., 1 tab.

Cobb, J.T. Jr. (Pittsburgh Univ., PA (USA)); Ahn, Y.K. (Gilbert/Commonwealth, Inc., Reading, PA (USA)); Angelo, J.F. (Universal Energy International, Inc., Little Rock, AR (USA))

1990-01-01

247

Internal combustion engine method for delayed reaction stratified combustion  

Microsoft Academic Search

A method of delayed reaction stratified combustion for internal combustion engines comprising burning a compressed fast burning rich air-fuel mixture during an initial portion of a combustion event, adding supplemental diluting air optimally with recirculated exhaust gas (EGR) during an intermediate portion of such combustion event and completing combustion during latter portions of the combustion event. Suggested timing and mixture

Cataldo

1984-01-01

248

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

249

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

250

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

251

Modeling of electron behaviors under microwave electric field in methane and air pre-mixture gas plasma assisted combustion  

NASA Astrophysics Data System (ADS)

Recently, plasma-assisted combustion [1] has been focused on for achieving more efficient combustion way of fossil fuels, reducing pollutants and so on. Shinohara et al [2] has reported that the flame length of methane and air premixed burner shortened by irradiating microwave power without increase of gas temperature. This suggests that electrons heated by microwave electric field assist the combustion. They also measured emission from 2nd Positive Band System (2nd PBS) of nitrogen during the irradiation. To clarify this mechanism, electron behavior under microwave power should be examined. To obtain electron transport parameters, electron Monte Carlo simulations in methane and air mixture gas have been done. A simple model has been developed to simulate inside the flame. To make this model simple, some assumptions are made. The electrons diffuse from the combustion plasma region. And the electrons quickly reach their equilibrium state. And it is found that the simulated emission from 2nd PBS agrees with the experimental result.[0pt] [1] V.Bychkov et al., IEEE Trans. Plasma Sci.,37,12 2280-2285(2009)[0pt] [2] K.Shinohara et al, J.Phys.D:Appl.Phys., 42, 182008 (1-7) (2009).

Akashi, Haruaki; Sasaki, K.; Yoshinaga, T.

2011-11-01

252

Characteristics of Pyrolysis and Combustion of Polymers in Stagnation-Point Flow for Preheated and Diluted Air with H2O and CO2  

Microsoft Academic Search

Combustion experiments on polypropylene (PP) and polyethylene terephethalate (PET) in stagnation-point flow were performed to investigate the fundamental characteristics of these polymers in high-temperature air combustion (HiTAC). Numerical study was also performed to estimate the regression rate and to determine the kinetic parameter of pyrolysis. In the experiments on PP combustion, extinction limits and sooting limits were found to be

Kentaro Yoshinaga; Makoto Mori; Yasuhiro Ogami; Hideaki Kobayashi

2008-01-01

253

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

254

Experimental Behavior of Pentaborane-Air Combustion Products During Expansion in a Convergent Divergent Nozzle  

NASA Technical Reports Server (NTRS)

In order to evaluate the post combustion behavior of boric oxide, pentaborane-air mixtures, burned to completion at a combustor pressure of 3 atmospheres, were expanded through a 7.1-inch-long convergent-divergent nozzle having a 4-inch-diameter throat and an exit-to-throat area ratio of 1.68. The experimentally determined thrust performance was in good agreement with the ideal equilibrium performance at stagnation temperatures of 3300 deg R and lower. The boric oxide vapor at the combustor exit required about 400 F deg supercooling before any condensed phase was observed. For a given thrust, fuel consumption was as much as 20 percent greater than predicted from vapor-pressure data for combustor outlet temperatures i n the vicinity of 3600 deg R. A similar result could be expected in full-scale engines, since the test combustor provided an unusually long dwell time and a highly turbulent environment. During the expansion process, the vapor (when present) did not condense to the extent predicted for an equilibrium expansion process. Moreover, condensation was observed only i n the form of small, abrupt phase changes i n the subsonic flow near the throat. Friction, due to liquid boric oxide films on the nozzle surfaces, was negligible when the surface temperature was above 800 F.

Branstetter, J. R.; Setze, P. C.

1958-01-01

255

Device for regulating the fuel-air ratio in internal combustion engines  

SciTech Connect

A device is proposed for regulating the fuel-air ratio in the operating mixture of an internal combustion engine and for monitoring the operational readiness of a lambda sensor controlling the regulating device and functioning by the principle of ion conduction in solid electrolytes. The lambda sensor has an adjustable, constant reference voltage switched opposite to it. The reference voltage approximately equals the average sensor output voltage. The level of the resultant voltage, which is established with the aid of the resultant current and has values located symmetrically with respect to the reference voltage, is monitored by comparator devices. The output signal of the comparator devices is logically processed and furnishes a signal as to the operational readiness of the sensor. In order to generate the reference voltage, a voltage divider branch having high resistance is disposed parallel to a voltage divider branch of relatively low resistance; the latter voltage divider branch further serves to establish the threshold values of the comparator devices. Because it is independent of the current draw of the comparator devices, the desired reference voltage can be adhered to very precisely, and thus the desired regulating point at which closed-loop control or regulation begins of the regulating device can also be adhered to very precisely.

Drews, U.; Mohrle, W.; Werner, P.

1983-07-19

256

Method and apparatus for regulating the fuel-air ratio in internal combustion engines  

SciTech Connect

A method and an apparatus for regulating the fuel-air ratio of the operational mixture of an internal combustion engine and for monitoring the operational readiness of a lambda sensor controlling the regulating apparatus and functioning according to the principle of ionic conduction in fixed electrolytes. A constant reference voltage which approximately corresponds to the average sensor output voltage is connected opposite to the lambda sensor. The level of the resultant voltage thus established, the values of which are disposed symmetrically relative to the reference voltage, is utilized, along with the cooperation of a resultant electric current which causes a voltage drop across the temperature-dependent internal resistance of the lambda sensor as a gauge for the operational readiness of the lambda sensor. The pickup of the resultant voltage is accomplished by two comparison devices, whose logically evaluatable output signals are transformed via a logical linkage circuit into an operational readiness or unreadiness signal. A third comparison device serves the purpose of controlling the regulating apparatus. The third comparison device output is switched when the lambda sensor is not under the influence of any resultant electric current; as a result, no temperature dependent shift of the switchover point relative to the internal sensor voltage occurs and regulation can be effected with the regulating apparatus in a temperature in dependent manner to a desired point in the sensor voltage curve or to a desired lambda value.

Drews, U.; Mohrle, W.; Werner, P.

1982-08-24

257

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

258

Pyrolysis and Combustion Behavior of Ternary Fuel Blends in Air and Oxy-Fuel Conditions by Using TGA-FTIR  

Microsoft Academic Search

Pyrolysis and combustion tests of imported coal, an indigenous lignite, petcoke, and their 60\\/30\\/10 wt.% ternary blends were carried out in air and oxy-fuel conditions by using thermogravimetry analysis–Fourier transform infrared (TGA-FTIR). Pyrolysis results of the blend and its parent fuels show that weight loss profiles display similar trends up to 700 °C in both nitrogen and carbon dioxide atmospheres. However,

N. S. Yüzba??; N. Selçuk

2012-01-01

259

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.

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

2012-01-01

260

Analytical chemical kinetic investigation of the effects of oxygen, hydrogen, and hydroxyl radicals on hydrogen-air combustion  

NASA Technical Reports Server (NTRS)

Quantitative values were computed which show the effects of the presence of small amounts of oxygen, hydrogen, and hydroxyl radicals on the finite-rate chemical kinetics of premixed hydrogen-air mixtures undergoing isobaric autoignition and combustion. The free radicals were considered to be initially present in hydrogen-air mixtures at equivalence ratios of 0.2, 0.6, 1.0, and 1.2. Initial mixture temperatures were 1100 K, 1200 K, and 1500 K, and pressures were 0.5, 1.0, 2.0, and 4.0 atm. Of the radicals investigated, atomic oxygen was found to be the most effective for reducing induction time, defined as the time to 5 percent of the total combustion temperature rise. The reaction time, the time between 5 percent and 95 percent of the temperature rise, is not decreased by the presence of free radicals in the initial hydrogen-air mixture. Fuel additives which yield free radicals might be used to effect a compact supersonic combustor design for efficient operation in an otherwise reaction-limited combustion regime.

Carson, G. T., Jr.

1974-01-01

261

Visualization of turbulent combustion of TNT detonation products in a steel vessel  

NASA Astrophysics Data System (ADS)

Mixing and afterburning of TNT detonation products in a steel vessel are recorded by the use of the Schlieren visualization system and high speed photography. The vessel is filled with air or 50% oxygen enriched air. Overpressure histories at the vessel wall are also recorded by using pressure transducers. In these experiments nitrogen, air or 50% oxygen enriched air are used as vessel fillers. The Oppenheim-Kuhl theory of thermodynamics of closed systems is applied to estimate the released energy on the basis of pressure histories.

Wola?ski, P.; Gut, Z.; Trzci?ski, W. A.; Szyma?czyk, L.; Paszula, J.

262

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

263

Lithium Combustion: A Review.  

National Technical Information Service (NTIS)

This review deals with the chemical reactions, ignition, and combustion of lithium combustion in air and in the components of air, including oxygen, nitrogen, water, and carbon dioxide. It was found that lithium reacts vigorously with these substances. In...

R. A. Rhein

1990-01-01

264

Numerical Investigation of Fuel Dilution Effects on the Performance of the Conventional and the Highly Preheated and Diluted Air Combustion Furnaces  

Microsoft Academic Search

This numerical study investigates the effects of using a diluted fuel (50% natural gas and 50% N2) in an industrial furnace under several cases of conventional combustion (air with 21% O2 at 300 and 1273 K) and the highly preheated and diluted air (1273 K with 10% O2 and 90% N2) combustion (HPDAC) conditions using an in-house computer program. It

Kiomars Abbasi Khazaei; Ali Asghar Hamidi; Masoud Rahimi

2009-01-01

265

Modification of NASA Langley 8 Foot High Temperature Tunnel to provide a unique national research facility for hypersonic air-breathing propulsion systems  

NASA Technical Reports Server (NTRS)

A planned modification of the NASA Langley 8-Foot High Temperature Tunnel to make it a unique national research facility for hypersonic air-breathing propulsion systems is described, and some of the ongoing supporting research for that modification is discussed. The modification involves: (1) the addition of an oxygen-enrichment system which will allow the methane-air combustion-heated test stream to simulate air for propulsion testing; and (2) supplemental nozzles to expand the test simulation capability from the current nominal Mach number to 7.0 include Mach numbers 3.0, 4.5, and 5.0. Detailed design of the modifications is currently underway and the modified facility is scheduled to be available for tests of large scale propulsion systems by mid 1988.

Kelly, H. N.; Wieting, A. R.

1984-01-01

266

Modification of NASA Langley 8 foot high temperature tunnel to provide a unique national research facility for hypersonic air-breathing propulsion systems  

NASA Technical Reports Server (NTRS)

A planned modification of the NASA Langley 8-Foot High Temperature Tunnel to make it a unique national research facility for hypersonic air-breathing propulsion systems is described, and some of the ongoing supporting research for that modification is discussed. The modification involves: (1) the addition of an oxygen-enrichment system which will allow the methane-air combustion-heated test stream to simulate air for propulsion testing; and (2) supplemental nozzles to expand the test simulation capability from the current nominal Mach number to 7.0 include Mach numbers 3.0, 4.5, and 5.0. Detailed design of the modifications is currently underway and the modified facility is scheduled to be available for tests of large scale propulsion systems by mid 1988.

Kelly, H. N.; Wieting, A. R.

1984-01-01

267

Thermodynamic and transport properties of air and its products of combustion with ASTMA-A-1 fuel and natural gas at 20, 30, and 40 atmospheres  

NASA Technical Reports Server (NTRS)

The isentropic exponent, molecular weight, viscosity, specific heat at constant pressure, thermal conductivity, Prandtl number, and enthalpy were calculated for air, the combustion products of ASTM-A-1 jet fuel and air, and the combustion products of natural gas and air. The properties were calculated over a temperature range from 300 to 2800 K in 100 K increments and for pressures of 20, 30 and 40 atmospheres. The data for natural gas and ASTM-A-1 were calculated for fuel-air ratios from zero to stoichiometric in 0.01 increments.

Poferl, D. J.; Svehla, R. A.

1973-01-01

268

COMBUSTION CHARACTERISTICS AND EMISSION OF HAZARDOUS AIR POLLUTANTS IN COMMERCIAL FLUIDIZED BED COMBUSTORS FOR SEWAGE SLUDGE  

Microsoft Academic Search

Since the disposal of sewage sludge in ocean has been prohibited recently according to London Dumping Convention, technological need for treating sewage sludge safely and efficiently are getting increased in Korea. FBC (Fluidized Bed Combustor) technology has been selected and utilized as one of the alternatives because of combustible content in sludge, on-going process development to maintain the best combustion

Ha-Na Jang; Seong-Bum Park; Jeong-Hun Kim; Yong-Chil Seo

2011-01-01

269

The Effect of Hydrogen Enrichment on CH4Air Combustion in Strong Dilution  

Microsoft Academic Search

Lean premixed combustion is a solution to reduce flame temperatures and pollutant emissions, especially NOx. This will strongly use for the future internal combustion engines. But the main drawbacks are the decrease of the global burning speed and the misfire. The aim of this study is first to verify or not is the addition of an amount of hydrogen can

Toni Tatouh; Fabien Halter; Christine Mounaïm-Rousselle

270

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...

271

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...

272

Cavity ringdown measurements of OH radicals in microwave induced argon plasma assisted combustion of methane/air mixtures  

NASA Astrophysics Data System (ADS)

In order to study the mechanism of plasma assisted combustion, we have developed a system that injects a nonthermal low temperature atmospheric argon plasma into the burning flame of lean methane/air mixtures. The experimental results demonstrated the flammability enhancement of plasma assisted combustion in the lean flame of a fuel equivalence ratio as low as 0.2. In the argon plasma assisted combustion flame, we observed three different zones which were pure argon plasma zone, plasma-flame interacting zone, and pure flame zone. Optical emission studies showed distinct spectroscopic fingerprints of each zone. The emission intensities of OH radicals increased dramatically moving from pure plasma zone to plasma-flame interacting zone, and dropped severely from plasma-flame interacting zone to pure flame zone. In addition to the optical emission spectroscopy study, cavity ringdown spectroscopy (CRDS) was also applied in the measurements of absolute ground state OH radical number densities in the plasma assisted combustion flame. Results showed that the ground state OH radical number densities in the pure flame zone are on the order of 10^15 molecule/cm^3, and increasing within the range of first few millimeters from the combustor nozzle.

Wu, Wei; Wang, Chuji

2012-10-01

273

Experimental study on premixed CH{sub 4}/air mixture combustion in micro Swiss-roll combustors  

SciTech Connect

Excess enthalpy combustion is a promising approach to stabilize flame in micro-combustors. Using a Swiss-roll combustor configuration, excess enthalpy combustion can be conveniently achieved. In this work, three types of Swiss-roll combustors with double spiral-shaped channels were designed and fabricated. The combustors were tested using methane/air mixtures of various equivalence ratios. Both temperature distributions and extinction limits were determined for each combustor configuration at different methane mass flow rates. Results indicate that the Swiss-roll combustors developed in the current study greatly enhance combustion stability in center regions of the combustors. At the same time, excess enthalpy combustors of the Swiss-roll configuration significantly extend the extinction limits of methane/air mixtures. In addition, the effects of combustor configurations and thermal insulation arrangements on temperature distributions and extinction limits were evaluated. With heat losses to the environment being significant, the use of thermal insulations further enhances the flame stability in center regions of the Swiss-roll combustors and extends flammable ranges. (author)

Zhong, Bei-Jing; Wang, Jian-Hua [Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Engineering Mechanics, Tsinghua University, Beijing 100084 (China)

2010-12-15

274

Combustion of hydrogen:air mixtures in the VGES cylindrical tank. [PWR; BWR  

SciTech Connect

Sandia National Laboratories is currently involved in a number of experimental projects to provide data that will help quantify the threat of hydrogen combustion during nuclear plant accidents. Several experimental facilities are part of the Variable Geometry Experimental System (VGES). The purpose of this report is to document the experimental results from the first round of combustion tests performed at one of these facilities: a 5-m/sup 3/ cylindrical tank. The data provided by tests at this facility can be used to guide further testing and for the development and assessment of analytical models to predict hydrogen combustion behavior.

Benedick, W.B.; Cummings, J.C.; Prassinos, P.G.

1984-05-01

275

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

276

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

SciTech Connect

A combustible gas mixture composed of methane and carbon dioxide is generated in municipal solid waste landfills. A practical consequence of the collection of this fuel gas is the inclusion of some air in the collected product. The effects of such included nitrogen and oxygen on landfill gas operations are discussed. The effects include increased collection 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 using data and experience from the Mountain View, California, landfill gas recovery site as a basis. Useful supplemental fuel gas may be recovered despite the inclusion of air. Recommendations are given for establishing limits for nitrogen and oxygen content and minimizing the costs associated with their presence.

Not Available

1983-01-01

277

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

278

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

279

Cold start fuel\\/air mixture supply device for spark ignition internal combustion engines  

Microsoft Academic Search

A combined accelerator pump and cold start fuel\\/air mixture supply device has an automatic throttle valve in a mixture supply passage, a fuel control valve controlling flow of fuel drawn into the passage through an inlet upstream of the throttle valve, and an air valve upstream of the fuel inlet. A primary spring tends to seat the air valve. A

1984-01-01

280

Nonequilibrium Sulfur Capture and Retention in an Air cooled Slagging Coal Combustion.  

National Technical Information Service (NTIS)

Calcium oxide sorbents injected in a slagging combustor react with the sulfur released during coal combustion to form sulfur bearing particles, some of which are deposited on the liquid slag layer on the combustor wall. Since the solubility of sulfur in l...

B. Zauderer

1997-01-01

281

CHARACTERIZATION OF INCIDENTAL CARBONACEOUS NANOPARTICLES IN AMBIENT AIR AND COMBUSTION EXHAUST  

EPA Science Inventory

The most important result of this research is one of the most complete datasets to date on the presence of C60 in the aerosol phase in the natural environment. This study expects that C60 fullerenes will not be found at detectable levels in combustion exhaust, ambient carbo...

282

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

SciTech Connect

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, and a combustion control system. The flex-flame burner, developed and tested by GTI, provides an innovative firing process in which the flame shape and velocity can be controlled. The burner produces a flame that keeps oxygen away from the bath surface by including an O2-enriched fuel-rich zone on the bottom and an air-fired fuel-lean zone on the top. Flame shape and velocity can be changed at constant firing rate or held constant over a range of firing conditions. A non-intrusive optical sensor is used to monitor the flame at all times. Information from the optical sensor(s) and thermocouples can be used to control the flow of natural gas, air, and oxygen to the burner as needed to maintain desired flame characteristics. This type of control is particularly important to keep oxygen away from the melt surface and thus reduce dross formation. This retrofit technology decreases fuel usage, increases furnace production rate, lowers gaseous emissions, and reduces dross formation. The highest priority research need listed under Recycled Materials is to turn aluminum process waste into usable materials which this technology accomplishes directly by decreasing dross formation and therefore increasing aluminum yield from a gas-fired reverberatory furnace. Emissions of NOx will be reduced to approximately 0.3 lb/ton of aluminum, in compliance with air emission regulations.

Soupos, V.; Zelepouga, S.; Rue, D.

2005-06-30

283

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

284

Method and apparatus for fuel\\/air control of surface combustion burners  

Microsoft Academic Search

A system is described for use in controlling the operation of a surface burner generating a flame producing emissions having a carbon monoxide concentration, said system comprising: a detector means for generating electrical signal equivalents corresponding to the intensity of electromagnetic radiation from said flame; an air valve for providing a controlled flow of air to said surface burner in

Zabielski; M. F. Sr

1993-01-01

285

Contribution of solid fuel, gas combustion or tobacco smoke to indoor air pollutant concentrations in Irish and Scottish homes  

PubMed Central

There are limited data describing pollutant levels inside homes that burn solid fuel within developed country settings with most studies describing test conditions or the effect of interventions. This study recruited homes in Ireland and Scotland where open combustion processes take place. Open combustion was classified as coal, peat or wood fuel burning, use of a gas cooker or stove, or where there is at least one resident smoker. 24-hour data on airborne concentrations of particulate matter less than 2.5 microns in size (PM2.5), carbon monoxide (CO), endotoxin in inhalable dust and carbon dioxide (CO2), together with 2–3 week averaged concentrations of nitrogen dioxide (NO2) were collected in 100 houses during the winter and spring of 2009–2010. The geometric mean of the 24-hour time-weighted-average (TWA) PM2.5 concentration was highest in homes with resident smokers (99?g/m3 – much higher than the WHO 24-hour guidance value of 25 ?g/m3. Lower geometric mean 24-hour TWA levels were found in homes that burned coal (7 ?g/m3) or wood (6 ?g/m3) and in homes with gas cookers (7 ?g/m3). In peat-burning homes the average 24-hourPM2.5 level recorded was 11 ?g/m3. Airborne endotoxin, CO, CO2 and NO2 concentrations were generally within indoor air quality guidance levels.

Semple, S; Garden, C; Coggins, M; Galea, KS; Whelan, P; Cowie, H; Sanchez-Jimenez, A; Thorne, PS; Hurley, JF; Ayres, JG

2012-01-01

286

The promising chemical kinetics for the simulation of propane-air combustion with KIVA-II code  

NASA Technical Reports Server (NTRS)

The development of chemical kinetics for the simulation of propane-air combustion with the use of computer code KIVA-II since 1989 is summarized here. In order to let readers understand the general feature well, a brief description of the KIVA-II code, specially related with the chemical reactions is also given. Then the results of recent work with 20 reaction mechanism is presented. It is also compared with the 5 reaction mechanism. It may be expected that the numerical stability of the 20 reaction mechanism is better as compared to that of 5 reaction mechanism, but the CPU time of the CRAY computer is much longer. Details are presented in the paper.

Ying, S. J.; Gorla, Rama S. R.; Kundu, Krishna P.

1993-01-01

287

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

288

Air, Water, and Solid Residue Prioritization Models for Conventional Combustion Sources.  

National Technical Information Service (NTIS)

The report describes mathematical models that were developed to relatively rank the environmental impact of water and solid residue emissions. The water model, similar to an air prioritization model developed in an earlier study, is based on mass of emiss...

E. C. Eimutis C. M. Moscowitz J. L. Delaney R. P. Quill D. L. Zanders

1976-01-01

289

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...

290

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

NASA Astrophysics Data System (ADS)

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 zone. To verify the characters of this technique, experiment with a new developed visualization method, image processing on smog tracing with fractal dimension, is carried out on a cold model of 300 MW furnace designed with this technique. The result shows, compared to injection without counter flow, the center lines of counter flow injection go deeper into the chamber and form a smaller tangential circle, which means the rotating momentum of entire vortex is feebler and the exit gyration is weaker. It also shows that with counter flow, the fractal dimensions of boundary between primary jet and front fire side air is bigger, which means more intense turbulence and better mix. As a conclusion, with fractal dimension, image processing on smog tracing method can be a quantificational, convenient and effective visualization way without disturbing the flow field, and it's also acknowledged that ACCT has the following superiorities: high burn out rate, low NOx emission, stable burning, slagging preventing, and temp-bias reducing.

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

2010-03-01

291

Method and apparatus for controlling the solenoid current of a solenoid valve which controls the amount of suction of air in an internal combustion engine  

Microsoft Academic Search

This patent describes apparatus for controlling the solenoid current of a selenoid valve which controls the amount of suction air in an internal combustion engine, the apparatus comprising: (a) engine rotational speed detector means for detecting engine rotational speed; (b) aimed idle speed setting means for generating a signal corresponding to a predetermined idling speed; (c) first calculating means coupled

T. Kiuchi; A. Yasuoka

1988-01-01

292

Method and apparatus for controlling the solenoid current of a solenoid valve which controls the amount of suction of air in an internal combustion engine  

Microsoft Academic Search

This patent describes an apparatus for controlling the solenoid current of a solenoid valve which controls suction air in an internal combustion engine. The apparatus consists of: (a) engine rotational speed detector means for detecting engine rotational speed; (b) aimed idle speed setting means for generating a signal corresponding to a predetermined idling speed; (c) first calculating means coupled to

T. Kiuchi; H. Sakurai

1988-01-01

293

SET UP AND OPERATION OF A RECIRCULATING WETTED RIGID MEDIA EVAPORATIVE COOLER INSTALLED IN A GAS TURBINE COMBUSTION INLET AIR SYSTEM  

Microsoft Academic Search

A procedure for setting up and operating a recirculating evaporative cooler installed in the combustion air inlet system of a gas turbine is described. The procedure includes a recommendation for selecting the ambient operating wet and dry bulb temperatures. A description of the parameters used in the procedure and calculation methods are shown. In response to frequent inquiries about the

R. S. Johnson

294

Air Combustion of Elemental Boron with an Excess of Boron. A Thermodynamical Study ueber die Verbrennung von Elementarem Bor MIT Luft bei Borueberschuss. Eine Thermodynamische Studie.  

National Technical Information Service (NTIS)

A computation method for determining the composition of exhaust gases from the combustion of elemental boron and air in the case of excessive boron) was developed. The application of this method is limited to the lambda range between 0.67 and 1. Combustio...

E. Buechner K. Hinliem

1974-01-01

295

Method and apparatus for determining the proportions of the constituents of the air-fuel mixture supplied to an internal combustion engine  

Microsoft Academic Search

A method and apparatus are described for determining the proportions of the air-fuel mixture constituents supplied to an internal combustion engine from a mixture preparing device such as a carburator, a fuel injection device or other suitable mixture preparing device. The method according to the invention serves to simplify the processing of output signals that are supplied to a mixture

1980-01-01

296

Oxygen-sorptive and -desorptive properties of perovskite-related oxides under temperature-swing conditions for oxygen enrichment  

Microsoft Academic Search

A group of A- and\\/or B-site partially substituted strontium cobaltites was investigated for oxygen-sorptive properties under temperature-swing conditions in air. The cobaltites with perovskite structure desorbed and absorbed significant amounts of oxygen quickly as well as reversibly on heating or cooling in the temperature range between 300 and 1000 °C, while those with brownmillerite or 2H-BaNiO3 structure either lacked oxygen-sorptive

Hajime Kusaba; Go Sakai; Kengo Shimanoe; Norio Miura; Noboru Yamazoe

2002-01-01

297

A numerical study of hydrogen-air combustion within a supersonic boundary layer  

SciTech Connect

A numerical study of the ignition and spread of combustion within a supersonic boundary layer is presented for case where ignition is triggered by viscous dissipation and/or wall temperature effects. Three important regions are found in the boundary layer in the streamwise direction. They are: (1) an induction region where the process is mainly controlled by streamwise convection and chemical kinetics in the presence of transverse molecular transports, (2) a thermal runaway region corresponding to a large chemical heat release, (3) a flame region which develops at the end of the thermal runaway region where a flame is stabilized at the outer edge of the boundary layer. The whole chemical process becomes endothermic for large values of free-stream Mach numbers due to intense dissociation effects. 11 refs.

Figueira da silva, L.F.; Deshaies, B.; Champion, M. (Ecole Nationale Superieure de Mecanique et d'Aerotechnique, Poitiers, (France))

1992-01-01

298

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

299

Laboratory study of air–water–coal combustion product (fly ash and FGD solid) mercury exchange  

Microsoft Academic Search

Recent laboratory research has indicated that coal fly ash derived from subbituminous and bituminous type coals is a sink for atmospheric mercury (Hg), however lignite-based ash was found to emit Hg to the air. Solids collected from systems with components that enhance Hg removal (i.e. activated carbon injection (ACI), flue gas desulfurization (FGD), and selective catalytic reduction (SCR) or selective

Mei Xin; Mae Sexauer Gustin; Kenneth Ladwig

2006-01-01

300

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...

301

Temperature measurements by CARS and intrusive probe in an air–hydrogen supersonic combustion  

Microsoft Academic Search

Static and stagnation temperature measurements are performed by CARS and by an intrusive probe in a Mach 2 cylindrical jet of hydrogen, injected into a Mach 2 coflow of air. The single-shot CARS static temperature measurements are based on nitrogen. A stagnation temperature probe has been developed and tested. This method consists in identifying the transient regime of a thermocouple

P Magre; G Collin; O Pin; J. M Badie; G Olalde; M Clément

2001-01-01

302

Air-cooled type intercooler for a supercharged internal combustion engine  

Microsoft Academic Search

A vehicle is described comprising an engine room having a radiator grille at a front end, an engine room hood lock support at a position behind the radiator grille, a bumper located below the radiator grille, and an air dam skirt located below the bumper. A transversely extending chamber-like space is formed between the radiator grille, the hood lock support,

T. Saito; A. Kotani

1987-01-01

303

Studies on the mixing of liquid jets and pre-atomized sprays in confined swirling air flows for lean direct injection combustion  

NASA Astrophysics Data System (ADS)

A lean direct injection (LDI) combustion concept was introduced recently to obtain both low NOsbx emissions and high performance for advanced aircraft gas turbine engines. It was reported that pollutant emissions, especially NOsbx, in a lean combustion mode depend significantly on the degree of mixing (mixedness) of supplied air and liquid fuel droplets. From a viewpoint of environmental protection, therefore, uniform mixing of fuel and air in a very short period of time, i.e., well-stirred mixing, is crucially important in the LDI combustion mode. In the present study, as the first stage toward understanding the combustion phenomena in a lean direct injection (LDI) mode, the hydrodynamic behavior of liquid jets and pre-atomized sprays in confined swirling air flows is investigated. Laser-based flow visualization and image analysis techniques are applied to analyze the instantaneous motion of the mixing process of the jets and pre-atomized sprays. Statistical analysis system (SAS) software is utilized to analyze the experimental data, and correlate experimental parameters. Statistical parameters, such as centrality, degree of spread, and total area ratio of particles, are defined in this study, and used to quantify the mixedness (degree of mixing) of liquid particles in confined geometry. Two empirical equations are obtained to predict jet intact lengths and spray angles, respectively, in confined swirling air flows. It is found that initial jet characteristics, such as intact length and spray angle, determine the mixing of the liquid particles resulting from the jet. It is verified that image analysis is feasible in quantitative determination of the mixedness of liquid particles. Even though substantial improvements in liquid fuel injector systems are required before they can be considered adequate for LDI combustion at high pressure and high temperature, the results and ideas obtained from the present study will help engineers find better mixing methods for LDI combustors.

Huh, Jun-Young

304

Model of Non-premixed Combustion of Aluminium---Air Mixtures  

NASA Astrophysics Data System (ADS)

For solving the problem of shock-induced dissemination and burning of aluminium particles in air, we have developed a new solver based on equilibrium equation of states (EOS) of 2-phase reactive mixtures. The solver uses two pre-calculated tables; the larger one describes the equilibrium states of reaction products and the smaller one describes states of fresh air. Being linked with gas-dynamics equations, the solver finds iteratively the mixture pressure and temperature; in addition it furnishes a complete description of chemical and physical transformations. 2D numerical simulations give encouraging agreement with experimental pressure histories recorded on the chamber wall. It is shown that multiple blast wave reflections from the walls of the chamber strongly accelerate particle burning. The results demonstrate the advantages of the equilibrium EOS model and appeal for 3D AMR calculations on massively-parallel computers, which should better define the initial stage of turbulent particle dissemination.

Khasainov, Boris; Kuhl, Allen; Victorov, Sergey; Neuwald, Peter

2005-07-01

305

Numerical simulation of turbulent propane-air combustion with non-homogeneous reactants: initial results  

Microsoft Academic Search

High-resolution two-dimensional numerical simulations have been initiated for pre- mixed turbulent propane-air flames propagating into regions of non-homogeneous reactant stoichiometry. Simulations include complex chemical kinetics, realistic molecular transport, and fully resolved hydrodynamics (no turbulence model). Aero- thermochemical conditions (pressure, temperature, stoichiometry, and turbulence velocity scale) approach those in an automotive gasoline direct-injection (GDI) en- gine at a low-speed, light-load operating

D. Haworth; B. Cuenot; T. Poinsot; R. Blint

306

Two-Stage Ignitions During Rapid Compression: Spontaneous Combustion in Lean Fuel-Air Mixtures  

Microsoft Academic Search

The two-stage ignition of acetaldehyde + oxygen-nitrogen (`air') mixture is investigated under rapid compression. The conditions are parallel to those brought about during the compression stroke in spark ignition and diesel engines. An approximately tenfold compression of pre-mixed gases is brought about mechanically. The time for rapid motion of the piston is 22 ms, and gases are ultimately compressed into

J. F. Griffiths; S. M. Hasko

1984-01-01

307

Explosive model of low-speed combustion of gaseous hydrocarbon-air mixtures  

Microsoft Academic Search

An explosive model is proposed for the calculation of the stationary velocity in mixtures of air and combined fuel consisting\\u000a of various gaseous hydrocarbons. The required equations are obtained from a consideration of the flame-front structure on\\u000a the basis of the thermal diffusion theory. In contrast to known relationships, the proposed model does not contain any ambiguities\\u000a in the equation

U. V. Tunik; G. D. Smekhov

1998-01-01

308

Air extraction and LBTU coal gas combustion in gas turbines for IGCC systems  

SciTech Connect

The primary objective of the cold flow experiments is to study the effects of air extraction from two sites in a heavy-frame gas turbine: (1) the engine wrapper or manholes and (2) the compressor/combustor prediffuser inlet. The experiments involve a scale model of components of a state-of-the-art, US made gas turbine between the compressor exit and the turbine inlet Specifically, the purpose is to observe and measure how air extraction affects the flow distribution around the combustor cans and the impingement cooling flow rates on transition pieces of the combustor. The experimental data should provide turbine manufacturers the information needed to determine their preferred air extraction site. The secondary objectives for the experiments are as follows: (1) to identify regions with high-pressure losses, (2) to develop a dam base which will validate computational fluid dynamic calculations, and (3) to establish an experimental facility which may be used to assist the US industry in improving the aerodynamic design of nonrotating components of a heavy-frame gas turbine.

Yang, Tah-teh; Agrawal, A.K.; Kapat, J.S.

1992-01-01

309

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

310

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

311

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

312

Fuel-Air Mixing Effect on Nox Emissions for a Lean Premixed-Prevaporized Combustion System  

NASA Technical Reports Server (NTRS)

The lean premixed-prevaporized (LPP) concept effectively meets low nitrogen oxides (NOx) emission requirements for combustors with the high inlet temperature and pressure typical of the High-Speed Civil Transport (HSCT). For the LPP system fuel-air mixture uniformity is probably the most important factor for low NOx emissions. Previous studies have suggested that the fuel-air mixture uniformity can be severely affected by changing the number and configuration of fuel injection points. Therefore, an experimental study was performed to determine how the number of fuel injection points and their arrangement affect NOx emissions from an LPP system. The NOx emissions were measured by a gas-sampling probe in a flame-tube rig at the following conditions: inlet temperature of 810 K (1000 F), rig pressure of 10 atm, reference velocity of 150 ft/s, and residence time near 0.005 s. Additionally, a focused Schlieren diagnostic technique coupled with a high speed camera was used to provide a qualitative description of the spatial flow field.

Lee, Chi-Ming; Chun, Kue S.; Locke, Randy J.

1995-01-01

313

Gas\\/air mixing valve  

Microsoft Academic Search

This patent describes a gas\\/air mixing valve for connection to an air plenum to regulate the flow of combustion reactants to a burner. It comprises: a valve body defining a gas inlet for receiving a supply of combustion gas, a combustion air inlet orifice in communication with the air plenum for receiving a supply of air for combustion, a bleed

M. Nunes; M. P. Grimanis; J. R. Hurley; K. C. Shukla

1990-01-01

314

Combustion oscillation control  

SciTech Connect

Premixing of fuel and air can avoid high temperatures which produce thermal NOx, but oscillating combustion must be eliminated. Combustion oscillations can also occur in Integrated Gasification Combined Cycle turbines. As an alternative to design or operating modifications, METC is investigating active combustion control (ACC) to eliminate oscillations; ACC uses repeated adjustment of some combustion parameter to control the variation in heat release that drives oscillations.

Richards, G.A.; Janus, M.C.

1996-12-31

315

Atomization and combustion characteristics of antimisting fuels using JT8D and air-boost injectors  

NASA Technical Reports Server (NTRS)

The atomization levels of antimisting fuels are presently determined for a JT8D fuel injector, a low emission airblast JT8D injector, and an air-boost injector, at operating conditions simulating engine operating conditions. The effects of the use of antimisting kerosene (AMK) on component performance are also studied in the case of an in-service JT8D engine. The use of the AMK fuel causes a decline in the quality of the spray, most notably as a large increase in the Sauter mean diameter for all three injector types. In addition, the idle patternation data obtained indicate that the low emission injector fuel distribution changed from a hollow cone Jet A spray having no fuel at its center to a semihollow spray cone in the case of AMK; this change could disrupt the combustor primary zone recirculation pattern.

Kennedy, J. B.; Florentino, A. J.

1986-01-01

316

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

317

Understanding carbon isotope behaviour during combustion processes: a pre-requisite to using d13C in the field of air pollution.  

NASA Astrophysics Data System (ADS)

Recent studies have demonstrated the effectiveness of stable isotopes in the field of air pollution research, especially their success in clearly discriminating the different sources of pollution in urban environments, and in tracing their respective impacts for a given sampling location. Among them, carbon isotopes have been used to track the origin of both gases (i.e. CO2; Widory &Javoy, 2003) and particulate matter (i.e. PM2 .5 and PM10; Widory et al., 2004). But understanding the carbon isotope behaviour that leads to this discrimination during combustion processes is a pre-requisite to using them as tracers of pollution sources in the atmosphere. d13C in fuels has been extensively used as an indicator of the processes leading to the generation of their parent crude-oil. Here, we isotopically characterise fuels and combustibles sold in Paris (France), and characterise the isotopic relations existing with their combustion by-products, i.e. gases (CO2) and particles (bulk carbon). Results show that d13C in fuels is clearly related to their physical state, with natural gas being strongly depleted in 13C while coal yields the highest d13C, and liquid fuels display intermediate values. This relation is also valid for exhaust gases, though d13C values of combustion particles form a homogeneous range within which no clear distinction is observed. Combustion processes are accompanied by carbon-isotope fractionation resulting from the combustion being incomplete. Carbon-isotope fractionation is strictly negative ( 1.3‰) during the formation of combustion gases, but generally positive in particle formation even if values close to zero are observed. This study helps understanding the processes leading to the d13C discrimination observed in pollution sources' exhausts, and definitely validates the use of carbon isotopes as tracers of atmospheric pollution.

Negrel, P.; Widory, D.

2006-12-01

318

Battery-powered PM10 indoor air samplers applied to unvented third world residential combustion sources. Report for June 1987March 1992  

Microsoft Academic Search

The paper discusses a battery-powered PM-10 indoor air sampler applied to unvented Third World residential combustion sources. The limited availability of reliable electric power away from the main towns meant that battery-powered systems were needed to collect integrated samples of the actual indoor exposure. The samplers incorporate horizontal elutriator PM-10 inlets and 8 by 10 in. (20 by 25 cm)

D. B. Harris; R. S. Chapman; J. L. Mumford

1993-01-01

319

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

320

Quality of a High?Enthalpy Flow upon Electric?Arc Heating of Air in a Facility for Investigating Supersonic Combustion  

Microsoft Academic Search

The quality of a high-enthalpy air flow is considered in terms of simulating full-scale flow parameters in studying supersonic combustion. It is shown that the plasmatron with gas-vortex stabilization of the arc, which was used in experiments, can provide, in a wide range of pressures and temperatures, a level of specific erosion of electrodes equal to 10-7–10-9 kg\\/C and a

V. A. Zabaikin

2003-01-01

321

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 Central

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.

Topaz, Moris

2012-01-01

322

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

323

Effect of airstream velocity on mean drop diameters of water sprays produced by pressure and air atomizing nozzles. [for combustion studies  

NASA Technical Reports Server (NTRS)

A scanning radiometer was used to determine the effect of airstream velocity on the mean drop diameter of water sprays produced by pressure atomizing and air atomizing fuel nozzles used in previous combustion studies. Increasing airstream velocity from 23 to 53.4 meters per second reduced the Sauter mean diameter by approximately 50 percent with both types of fuel nozzles. The use of a sonic cup attached to the tip of an air assist nozzle reduced the Sauter mean diameter by approximately 40 percent. Test conditions included airstream velocities of 23 to 53.4 meters per second at 293 K and atmospheric pressure.

Ingebo, R. D.

1977-01-01

324

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

325

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.

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

2011-01-01

326

OXYGEN ENHANCED COMBUSTION FOR NOx CONTROL  

SciTech Connect

Increased environmental regulations will require utility boilers to reduce NO{sub x} emissions to less than 0.15lb/MMBtu in the near term. Conventional technologies such as Selective Catalytic Reduction (SCR) and Selective Non-Catalytic Reduction (SNCR) are unable to achieve these lowered emission levels without substantially higher costs and major operating problems. Oxygen enhanced combustion is a novel technology that allows utilities to meet the NO{sub x} emission requirements without the operational problems that occur with SCR and SNCR. Furthermore, oxygen enhanced combustion can achieve these NO{sub x} limits at costs lower than conventional technologies. The objective of this program is to demonstrate the use of oxygen enhanced combustion as a technical and economical method of meeting the EPA State Implementation Plan for NO{sub x} reduction to less than 0.15lb/MMBtu for a wide range of boilers and coal. The oxygen enhanced coal combustion program (Task 1) focused this quarter on the specific objective of exploration of the impact of oxygen enrichment on NO{sub x} formation utilizing small-scale combustors for parametric testing. Research efforts toward understanding any limitations to the applicability of the technology to different burners and fuels such as different types of coal are underway. The objective of the oxygen transport membrane (OTM) materials development program (Task 2.1) is to ascertain a suitable material composition that can be fabricated into dense tubes capable of producing the target oxygen flux under the operating conditions. This requires that the material have sufficient oxygen permeation resulting from high oxygen ion conductivity, high electronic conductivity and high oxygen surface exchange rate. The OTM element development program (Task 2.2) objective is to develop, fabricate and characterize OTM elements for laboratory and pilot reactors utilizing quality control parameters to ensure reproducibility and superior performance. A specific goal is to achieve a material that will sinter to desired density without compromising other variables such as reaction to binder systems or phase purity. Oxygen-enhanced combustion requires a facility which is capable of supplying high purity oxygen (>99.5%) at low costs. This goal can be achieved through the thermal integration of high temperature air separation with ceramic OTM. The objective of the OTM process development program (Task 2.3) is to demonstrate successfully the program objectives on a lab-scale single OTM tube reactor under process conditions comparable to those of an optimum large-scale oxygen facility. This quarterly technical progress report will summarize work accomplished for the Program through the first quarter April--June 2000 in the following task areas: Task 1 Oxygen Enhanced Coal Combustion; Task 2 Oxygen Transport Membranes; and Task 4 Program Management.

Lawrence E. Bool; Jack C. Chen; David R. Thompson

2000-07-01

327

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.

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

2012-01-01

328

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 ...

329

Initiation of diffusion combustion in a supersonic flow of H2–air mixture by electrical-discharge-excited oxygen moleculesThis paper was presented at the Third International Symposium on Nonequilibrium Processes, Combustion, and Atmospheric Phenomena (Dagomys, Sochi, Russia, 25–29 June 2007)  

Microsoft Academic Search

The methodology of arranging a stable combustion in a diffusion mode in a supersonic non-premixed H2–air flow at a short distance and at a low air temperature due to excitation of O2 molecules to the a 1?g and states in the electrical discharge is considered. It is shown that for initiation of combustion in this case, it is sufficient to

A M Starik; N S Titova; L V Bezgin; V I Kopchenov

2008-01-01

330

Municipal Wastewater Sludge Combustion Technology.  

National Technical Information Service (NTIS)

The publication describes and evaluates the various municipal sludge combustion systems. It also emphasizes the necessity for considering and evaluating the costs involved in the total sludge management train, including dewatering, combustion, air polluti...

1985-01-01

331

MUNICIPAL WASTEWATER SLUDGE COMBUSTION TECHNOLOGY  

EPA Science Inventory

The publication describes and evaluates the various municipal sludge combustion systems. It also emphasizes the necessity for considering and evaluating the costs involved in the total sludge management train, including dewatering, combustion, air pollution control, and ash dispo...

332

Effects of Turbulence on Flame Structure and NOx Emission of Turbulent Jet Non-Premixed Flames in High-Temperature Air Combustion  

NASA Astrophysics Data System (ADS)

Turbulent jet non-premixed flame under the conditions of High Temperature Air Combustion (HiCOT) was investigated. Air diluted with nitrogen was preheated up to about 1300K. Propane was injected through a fuel tube parallel to the preheated airflow. LDV measurement of turbulence, CH-PLIF for reaction zone visualization, and NOx concentration measurements in the burnt gas were performed and the relations between these characteristics were examined. Results showed that turbulence intensity generated by perforated plate installed upstream of the fuel tube was high at high-temperature airflow due to high velocity compared with that at room temperature airflow when the flow rate was controlled to keep the excess air ratio constant regardless of preheating. The reaction zone represented by the CH-PLIF images still had a thin structure even in the HiCOT condition of oxygen concentration of 8vol.%. The flow turbulence in the combustion duct played a significant role in decreasing NOx emission. Due to turbulence, flame was broken and a bubble-like flame structure was generated, especially in the lifted flame cases, implying that the burning fuel lumps flow a considerable distance in air with a low oxygen concentration and generate uniform heat release profiles in HiCOT furnaces.

Kobayashi, Hideaki; Oono, Ken; Cho, Eun-Seong; Hagiwara, Hirokazu; Ogami, Yasuhiro; Niioka, Takashi

333

Flame combustion of carbonaceous fuels  

SciTech Connect

A method for improving the flame combustion of carbonaceous fuels. The method enables the reduction of oxides of nitrogen generated by the flame combustion, and enables an improvement in boiler efficiency. An ionic sodium or potassium compound, or a combination of them, is supplied with the combustible mixture of fuel and air so as intimately and uniformly to be present where and when the flame exists. Preferably the compound is supplied in an aqueous solution, and can be intimately mixed with the fuel, or with the atomizing air or steam, or with the combustion air. The process is useful with both single-stage and staged (multiple-staged) combustion systems.

Hampton, W.J.; Hatch, R.L.; James, G.R.

1984-05-08

334

Method and system for controlling the supply of fuel and air to a furnace  

Microsoft Academic Search

This patent describes a method for providing fuel and air to a furnace through a burner assemblies, each burner assembly including a combustion air register, each combustion air register including a combustion air passageway that produces a discrete air flow path of combustion air, an air valve for controlling the flow of combustion air through the burner assembly, and an

D. K. Hagar; R. W. McIntyre

1990-01-01

335

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

336

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...

337

Experimental and numerical study of the accuracy of flame-speed measurements for methane/air combustion in a slot burner  

SciTech Connect

Measuring the velocities of premixed laminar flames with precision remains a controversial issue in the combustion community. This paper studies the accuracy of such measurements in two-dimensional slot burners and shows that while methane/air flame speeds can be measured with reasonable accuracy, the method may lack precision for other mixtures such as hydrogen/air. Curvature at the flame tip, strain on the flame sides and local quenching at the flame base can modify local flame speeds and require corrections which are studied using two-dimensional DNS. Numerical simulations also provide stretch, displacement and consumption flame speeds along the flame front. For methane/air flames, DNS show that the local stretch remains small so that the local consumption speed is very close to the unstretched premixed flame speed. The only correction needed to correctly predict flame speeds in this case is due to the finite aspect ratio of the slot used to inject the premixed gases which induces a flow acceleration in the measurement region (this correction can be evaluated from velocity measurement in the slot section or from an analytical solution). The method is applied to methane/air flames with and without water addition and results are compared to experimental data found in the literature. The paper then discusses the limitations of the slot-burner method to measure flame speeds for other mixtures and shows that it is not well adapted to mixtures with a Lewis number far from unity, such as hydrogen/air flames. (author)

Selle, L.; Ferret, B. [Universite de Toulouse, INPT, UPS, IMFT, Institut de Mecanique des Fluides de Toulouse (France); CNRS, IMFT, Toulouse (France); Poinsot, T. [Universite de Toulouse, INPT, UPS, IMFT, Institut de Mecanique des Fluides de Toulouse (France); CNRS, IMFT, Toulouse (France); CERFACS, Toulouse (France)

2011-01-15

338

Research on ignition and combustion in oxygen systems  

NASA Technical Reports Server (NTRS)

The work on ignition and combustion research in oxygen systems under the sponsorship of NASA's Aerospace Safety Research and Data Institute is described. Preliminary results of ignition of nonmetallic materials by electric arc and mechanical impact are presented. Ignition by a resonant process involving repeated shock waves has been demonstrated and some of the results included. In addition, results of studies concerned with ignition due to the rapid rupture of metal films and diaphragms are reviewed. Burning rate studies of three nonmetallic materials in oxygen enriched environments were completed and the results presented. A brief description of these combustion studies under zero gravity is also included. These results are compared to combustion under one gravity.

Ordin, P. M.

1973-01-01

339

A Novel High-Heat Transfer Low-NO{sub x} Natural Gas Combustion System. Final Technical Report  

SciTech Connect

A novel high-heat transfer low NO(sub x) natural gas combustion system. The objectives of this program are to research, develop, test, and commercialize a novel high-heat transfer low-NO{sub x} natural gas combustion system for oxygen-, oxygen-enriched air, and air-fired furnaces. This technology will improve the process efficiency (productivity and product quality) and the energy efficiency of high-temperature industrial furnaces by at least 20%. GTI's high-heat transfer burner has applications in high-temperature air, oxygen-enriched air, and oxygen furnaces used in the glass, metals, cement, and other industries. Development work in this program is focused on using this burner to improve the energy efficiency and productivity of glass melting furnaces that are major industrial energy consumers. The following specific project objectives are defined to provide a means of achieving the overall project objectives. (1) Identify topics to be covered, problems requiring attention, equipment to be used in the program, and test plans to be followed in Phase II and Phase III. (2) Use existing codes to develop models of gas combustion and soot nucleation and growth as well as a thermodynamic and parametric description of furnace heat transfer issues. (3) Conduct a parametric study to confirm the increase in process and energy efficiency. (4) Design and fabricate a high-heat transfer low-NOx natural gas burners for laboratory, pilot- and demonstration-scale tests. (5) Test the high-heat transfer burner in one of GTI's laboratory-scale high-temperature furnaces. (6) Design and demonstrate the high-heat transfer burner on GTI's unique pilot-scale glass tank simulator. (7) Complete one long term demonstration test of this burner technology on an Owens Corning full-scale industrial glass melting furnace. (8) Prepare an Industrial Adoption Plan. This Plan will be updated in each program Phase as additional information becomes available. The Plan will include technical and economic analyses, energy savings and waste reduction predictions, evaluation of environmental effects, and outline issues concerning manufacturing, marketing, and financing. Combustion Tec, Owens Corning, and GTI will all take active roles in defining this Plan. During Phase I, the first three objectives were addressed and completed along with the design component of the fourth objective. In Phase II, the fabrication component of the fourth objective was completed along with objectives five and six. Results of the Phase I work were reported in the Phase I Final Report and are summarized in this Final Technical Report. Work for Phase II was divided in four specific Tasks. Results of the Phase II work were reported in the Phase II Final Report and are also summarized in this Final Technical Report. No Phase III Final Report was prepared, so this Final Technical Report presents the results of Phase III commercial demonstration efforts. A description of each Task in Phases I, II, and III is presented in this report.

Abbasi, H.

2004-01-01

340

Laminar air flow provides high air quality in the operating field even during real operating conditions, but personal protection seems to be necessary in operations with tissue combustion.  

PubMed

We measured bacterial and particle concentrations at the level of operative fields during 105 operation procedures under laminar air flow conditions. Measured concentrations were at least a factor of 20 lower than in comparable rooms without ultra-clean air and laminar air flow. Kind of operation (septic/aseptic), number of participating persons and quantity of talking seem to have less influence on air quality than presumed, single use cover improves the air quality. The number of ultra-fine and small particles was dramatically increased when tissue was coagulated during operation. This may pose health risks to surgeons and nurses, needs risk assessment and decisions about personal protection. PMID:16325554

Hansen, Dorothea; Krabs, Carsten; Benner, Daniel; Brauksiepe, Andreas; Popp, Walter

2005-01-01

341

Pilot-scale evaluation of the potential for emissions of hazardous air pollutants from combustion of tire-derived fuel. Final report, February 1992-October 1993  

SciTech Connect

Experiments were conducted in a 73kW (250,000 Btu/hr) rotary kiln incinerator simulator to examine and characterize emissions from incineration of scrap tire material. The purposes of this project are to: (1) generate a profile of target analytes for full-scale stack sampling efforts, not to generate statistically defensible emission factors for the controlled combustion of scrap tire material; and (2) where possible, give insight into the technical issues and fundamental phenomena related to controlled combustion of scrap tires. Along with continuous emissions monitoring for oxygen (O2), carbon dioxide (CO2), carbon monoxide (CO), nitric oxide (NO), sulfur dioxide (SO2), and total hydrocarbons (THCs), samples were taken to examine volatile and semi-volatile organics, polychlorinated p-dibenzodioxins and dibenzofurans (PCDD/PCDF), and metal aerosols. In addition, a continuous polycyclic aromatic hydrocarbon (PAH) analyzer was used in all the tests. Samples were analyzed with an emphasis on the 189 hazardous air pollutants (HAPs) listed in the 1990 Clean Air Act Amendments (CAAA), but other compounds were also identified where possible.

Lemieux, P.M.

1994-05-01

342

Combustion characteristics and flame stability at the microscale: a CFD study of premixed methane\\/air mixtures  

Microsoft Academic Search

A two-dimensional elliptic, computational fluid dynamics (CFD) model of a microburner is solved to study the effects of microburner dimensions, conductivity and thickness of wall materials, external heat losses, and operating conditions on combustion characteristics and flame stability. We have found that the wall conductivity and thickness are very important as they determine the upstream heat transfer, which is necessary

D. G. Norton; D. G. Vlachos

2003-01-01

343

Direct injection internal combustion engine of compression ignition type  

Microsoft Academic Search

This patent describes a direct injection internal combustion engine of a compression ignition type in which air is sucked into a combustion chamber and compressed by a piston, and fuel is injected directly thereinto so as to be ignited and combusted, comprising: air intake means having swirling means for swirling intake air supplied to the combustion chamber; a piston having

A. Saito; K. Kozuka; Y. Oshima; M. Yamada; N. Mori; K. Sugiyama; T. Aoyama

1987-01-01

344

Combuster. [low nitrogen oxide formation  

NASA Technical Reports Server (NTRS)

A combuster is provided for utilizing a combustible mixture containing fuel and air, to heat a load fluid such as water or air, in a manner that minimizes the formation of nitrogen oxide. The combustible mixture passes through a small diameter tube where the mixture is heated to its combustion temperature, while the load fluid flows past the outside of the tube to receive heat. The tube is of a diameter small enough that the combustible mixture cannot form a flame, and yet is not subject to wall quench, so that combustion occurs, but at a temperature less than under free flame conditions. Most of the heat required for heating the combustible mixture to its combustion temperature, is obtained from heat flow through the walls of the pipe to the mixture.

Mckay, R. A. (inventor)

1978-01-01

345

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

346

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

347

Detonation cell size measurements in high-temperature hydrogen-air-steam mixtures at the BNL high-temperature combustion facility  

SciTech Connect

The High-Temperature Combustion Facility (HTCF) was designed and constructed with the objective of studying detonation phenomena in mixtures of hydrogen-air-steam at initially high temperatures. The central element of the HTCF is a 27-cm inner-diameter, 21.3-m long cylindrical test vessel capable of being heating to 700K {+-} 14K. A unique feature of the HTCF is the {open_quotes}diaphragmless{close_quotes} acetylene-oxygen gas driver which is used to initiate the detonation in the test gas. Cell size measurements have shown that for any hydrogen-air-steam mixture, increasing the initial mixture temperature, in the range of 300K to 650K, while maintaining the initial pressure of 0.1 MPa, decreases the cell size and thus makes the mixture more detonable. The effect of steam dilution on cell size was tested in stoichiometric and off-stoichiometric (e.g., equivalence ratio of 0.5) hydrogen-air mixtures. Increasing the steam dilution in hydrogen-air mixtures at 0.1 MPa initial pressure increases the cell size, irrespective of initial temperature. It is also observed that the desensitizing effect of steam diminished with increased initial temperature. A 1-dimensional, steady-state Zel`dovich, von Neumann, Doring (ZND) model, with full chemical kinetics, has been used to predict cell size for hydrogen-air-steam mixtures at different initial conditions. Qualitatively the model predicts the overall trends observed in the measured cell size versus mixture composition and initial temperature and pressure. It was found that the proportionality constant used to predict detonation cell size from the calculated ZND model reaction zone varies between 10 and 100 depending on the mixture composition and initial temperature. 32 refs., 35 figs.

Ciccarelli, G.; Ginsberg, T.; Boccio, J.L. [and others

1997-11-01

348

Computer Program for Obtaining Thermodynamic and Transport Properties of Air and Products of Combustion of ASTM-A-1 Fuel and Air.  

National Technical Information Service (NTIS)

A computer program for determining desired thermodynamic and transport property values by means of a three-dimensional (pressure, fuel-air ratio, and either enthalpy or temperature) interpolation routine was developed. The program calculates temperature (...

R. S. Colladay S. A. Hippensteele

1978-01-01

349

Method and apparatus for determining the proportions of the constituents of the air-fuel mixture supplied to an internal combustion engine  

SciTech Connect

A method and apparatus are described for determining the proportions of the air-fuel mixture constituents supplied to an internal combustion engine from a mixture preparing device such as a carburator, a fuel injection device or other suitable mixture preparing device. The method according to the invention serves to simplify the processing of output signals that are supplied to a mixture preparing device having at least two lambda sensors. The invention is especially suitable for use with large engines with several exhaust conduit systems, such as so-called v-engines, in which generally there is an unequal mixture distribution between the two rows of cylinders. By employing at least two lambda sensors in the exhaust gas conduit system for monitoring the exhaust gas composition, one succeeds in determining the mixture composition of the air-fuel mixture applied to all cylinders, and in influencing the air-fuel mixture in a suitable supplementary manner by a feed back of the actual value signals generated by the lambda sensors to the fuel preparation device, so that a desirable overall exhaust gas average value can be achieved. The apparatus employs two integrators and suitable logic circuitry for applying the lambda sensor signals to the integrators in such a manner that one integrator regulates the entire mixture in the desired direction, according to the sensor signals supplied to it, while the other integrator sets the amplitude of the oscillation fluctuations at a value that corresponds to the lambda differential.

Peter, C.

1980-11-04

350

Injection, atomization, ignition and combustion of liquid fuels in high-speed air streams. Annual scientific report 1 December 81-31 December 82  

SciTech Connect

A simulation approach to studying hot flow subsonic cross-stream fuel injection problems in a less complex and costly cold flow facility was developed. A typical ramjet combustion chamber fuel injection problem was posed where ambient temperature fuel (Kerosene) is injected into a hot airstream. This case was transformed through two new similarity parameters involving injection and freestream properties to a simulated case where a chilled injectant is injected into an ambient temperature airstream. Experiments for the simulated case using chilled Freon-12 injected into the Va. Tech 23 x 23 cm. blow-down wind tunnel at a freestream Mach number of 0.44 were run. The freestream stagnation pressure and temperature were held at 2.5 atm. and 300 degrees K respectively. Results showed a clear picture of the mechanisms of jet decomposition in the presence of rapid vaporization. Immediately after injection a vapor cloud was formed in the jet plume, which dissipated downstream leaving droplets on the order of 8 to 10 microns in diameter for the conditions examined. This represents a substantial reduction compared to baseline tests run at the same conditions with water which had little vaporization. The desirability of using slurry fuels for aerospace application has long been recognized, but the problems of slurry combustion have delayed their use. The present work is an experimental and numerical investigation into the break-up and droplet formation of laminar slurry jets issuing into quiescent air.

Schetz, J.A.

1983-01-01

351

Battery-powered PM-10 indoor air samplers applied to unvented third world residential combustion sources. Report for June 1987-March 1992  

SciTech Connect

The paper discusses a battery-powered PM-10 indoor air sampler applied to unvented Third World residential combustion sources. The limited availability of reliable electric power away from the main towns meant that battery-powered systems were needed to collect integrated samples of the actual indoor exposure. The samplers incorporate horizontal elutriator PM-10 inlets and 8 by 10 in. (20 by 25 cm) filters for large sample capacity at low system pressure drop. A requirement for an integrated 24-hour sample meant that the usual Ni-Cd battery of the 4 L/min personal sampling pump was replaced by a Pb-acid gelled-electrolyte unit. These samplers, which have been used to develop emissions, chemical and bioassay data for coals from several mines as well as emissions variability within each coal type, are described and typical data collected are presented. A new version using a 12 L/min pumping system is also described.

Harris, D.B.; Chapman, R.S.; Mumford, J.L.

1993-01-01

352

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

353

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

354

Hospital Waste Combustion Study Data Gathering Phase.  

National Technical Information Service (NTIS)

The report contains the results of a study of air emissions from hospital waste combustion. These results will allow the EPA to assess the need for and feasibility of regulating multipollutant emissions from hospital waste combustion. Information was gath...

1988-01-01

355

Computer program for obtaining thermodynamic and transport properties of air and products of combustion of ASTM-A-1 fuel and air  

Microsoft Academic Search

A computer program for determining desired thermodynamic and transport property values by means of a three-dimensional (pressure, fuel-air ratio, and either enthalpy or temperature) interpolation routine was developed. The program calculates temperature (or enthalpy), molecular weight, viscosity, specific heat at constant pressure, thermal conductivity, isentropic exponent (equal to the specific heat ratio at conditions where gases do not react), Prandtl

S. A. Hippensteele; R. S. Colladay

1978-01-01

356

Decomposition of nitric oxide in a hot nitrogen stream to synthesize air for hypersonic wind tunnel combustion testing  

NASA Technical Reports Server (NTRS)

A clean source of high enthalpy air was obtained from the exothermic decomposition of nitric oxide in the presence of strongly heated nitrogen. A nitric oxide jet was introduced into a confined coaxial nitrogen stream. Measurements were made of the extent of mixing and reaction. Experimental results are compared with one- and two-dimensional chemical kinetics computations. Both analyses predict much lower reactivity than was observed experimentally. Inlet nitrogen temperatures above 2400 K were sufficient to produce experimentally a completely reacted gas stream of synthetic air.

Zumdieck, J. F.; Zlatarich, S. A.

1974-01-01

357

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

358

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

359

Pulse combustion drying apparatus for particulate materials  

Microsoft Academic Search

This patent describes a pulse jet combustion apparatus for the drying of particulate material of the type having: a combustion chamber having an air entry end, an exhaust end and a common longitudinal axis therebetween, an air inlet conduit coaxially connected to the air entry and thereof, a primary exhaust gas conduit coaxially connected to the exhaust end thereof and,

R. R. Gray; V. M. Marguth

1987-01-01

360

CO{sub 2} emission abatement in IGCC power plants by semiclosed cycles: Part B -- With air-blown combustion and CO{sub 2} physical absorption  

SciTech Connect

This paper analyzes the fundamentals of IGCC power plants with carbon dioxide removal systems, by a cycle configuration alternative to the one discussed in Part A (with oxygen-blown combustion). The idea behind this proposal is to overcome the major drawbacks of the previous solution (large oxygen consumption and re-design of the gas turbine unit), by means of a semiclosed cycle using air as the oxidizer. Consequently, combustion gases are largely diluted by nitrogen and cannot be simply compressed to produce liquefied CO{sub 2} for storage or disposal. However, CO{sub 2} concentration remains high enough to make separation possible by a physical absorption process. It requires a re-pressurization of the flow subtracted from the cycle, with relevant consequences on the plant energy balance. The configuration and the thermodynamic performance of this plant concept are extensively addressed in the paper. As in the first part, the influence of the pressure ratio is discussed, but values similar to the ones adopted in commercial heavy-duty machines provide here acceptable performance. Proper attention was paid to the impact of the absorption process on the energy consumption. The resulting net overall efficiency is again in the 38--39% range, with assumptions fully comparable to the ones of Part A. Finally, the authors demonstrate that the present scheme enables the use of unmodified machines, but large additional equipment is required for exhausts treatment and CO{sub 2} separation. A final comparison between the two semiclosed cycle concepts is therefore addressed.

Chiesa, P.; Lozza, G.

1999-10-01

361

Some features of formation of local combustible hydrogen–air mixtures during continuous release of hydrogen in a room  

Microsoft Academic Search

A three-dimensional mathematical model is developed for heat and mass transfer in local non-uniform hydrogen–air mixtures that are formed during continuous release of hydrogen in a room. A comparison between simulation and experimental results is performed. Numerical investigation of characteristic parameters’ fields is made. Influence of vent opening and local burning upon mass concentration fields of hydrogen is investigated. The

S. V. Puzach

2003-01-01

362

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

363

Incineration of combustible waste materials  

Microsoft Academic Search

A method is described here of incinerating combustible waste materials comprises subjecting the materials to a temperature from about 500°C to about 925°C. This temperature is sufficient to gasify most of the combustible content. In the presence of a mixture of hot air and steam containing insufficient oxygen to support free combustion, the resulting gases blend with further hot gases

1987-01-01

364

Innovative Clean Coal Technology (ICCT): 500 MW demonstration of advanced wall-fired combustion techniques for the reduction of nitrogen oxide (NO{sub x}) emissions from coal-fired boilers. Phase 2, Overfire air tests  

SciTech Connect

This Phase 2 Test Report summarizes the testing activities and results for the second testing phase of an Innovative Clean Coal Technology (ICCT) demonstration of advanced wall-fired combustion techniques for the reduction of nitrogen oxide (NO{sub x}) emissions from coal-fired boilers. The second phase demonstrates the Advanced Overfire Air (AOFA) retrofit with existing Foster Wheeler (FWEC) burners. The project is being conducted at Georgia Power Company`s Plant Hammond Unit 4 located near Rome, Georgia. The primary goal of this project is the characterization of the low NO{sub x} combustion equipment through the collection and analysis of long-term emissions data supported by short-term characterization data. Ultimately a fifty percent NO{sub x} reduction target using combinations of combustion modifications has been established for this project.

Smith, L.L.; Hooper, M.P. [Energy Technology Consultants, Irvine, CA (United States)

1992-07-13

365

Seasonal, anthropogenic, air mass, and meteorological influences on the atmospheric concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs): Evidence for the importance of diffuse combustion sources  

SciTech Connect

Sampling programs were undertaken to establish air polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F) concentrations at a semirural site on the northwest coast of England in autumn and summer and to investigate factors causing their variability. Changing source inputs, meteorological parameters, air masses, and the impact of a festival when it is customary to light fireworks and bonfires were investigated. Various lines of evidence from the study point to diffuse, combustion-related sources being a major influence on ambient air concentrations. Higher PCDD/F concentrations were generally associated with air masses that had originated and moved over land, particularly during periods of low ambient temperature. Low concentrations were associated with air masses that had arrived from the Atlantic Ocean/Irish Sea to the west of the sampling site and had little or no contact with urban/industrialized areas. Concentrations in the autumn months were 2 to 10 times higher than those found in the summer.

Lee, R.G.M.; Green, N.J.L.; Lohmann, R.; Jones, K.C. [Lancaster Univ. (United Kingdom)] [Lancaster Univ. (United Kingdom)

1999-09-01

366

Jet plume injection and combustion system for internal combustion engines.  

National Technical Information Service (NTIS)

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 ...

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

1992-01-01

367

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...

368

Swirl control arrangement for internal combustion engine  

SciTech Connect

This patent describes, in an internal combustion engine having a combustion chamber, an induction system comprising: an induction passage leading to the combustion chamber; means for forming and air fuel mixture in one of the combustion chamber and the induction passage; an inlet valve which controls communication between the combustion chamber and the induction passage; a throttle valve disposed in the induction passage for controlling the amount of air which is inducted into the combustion chamber when the inlet valve is open; a swirl control valve disposed in the induction passage downstream of the throttle valve; a first sensor for sensing the pressure differential between the section of the induction passage upstream of the swirl control valve and the section of the induction passage downstream of the swirl control valve; a second sensor for sensing the air-fuel ration of the air-fuel mixture being combusted in the combustion chamber; a servo for controlling the position of the swirl control valve; and a control circuit responsive to the first and second sensors for controlling the servo in a manner to optimize the swirl generation within the combustion chamber for the air-fuel ratio of the air-fuel mixture being combusted in the combustion chamber.

Nakajima, Y.; Yoshimura, T.; Terakasa, K.

1987-03-24

369

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

370

Sensitivity of hazardous air pollutant emissions to the combustion of blends of petroleum diesel and biodiesel fuel  

NASA Astrophysics Data System (ADS)

Emission rates and composition of known hazardous air pollutants in the exhaust gas from a commercial agriculture tractor, burning a range of biodiesel blends operating at two different load conditions were investigated to better understand the emission characteristics of biodiesel fuel. Ultra-Low Sulfur Petroleum Diesel (ULSD) fuel was blended with soybean oil and beef tallow based biodiesel to examine fuels containing 0% (B0), 50% (B50) and 100% (B100) soybean oil based biodiesel, and 50% (B50T) and 100% (B100T) beef tallow biodiesel. Samples were collected using a dilution source sampler to simulate atmospheric dilution. Particulate matter and exhaust gases were analyzed for carbonyls, Volatile Organic Compounds (VOCs), and Polycyclic Aromatic Hydrocarbons (PAHs) to determine their respective emission rates. This analysis is focused on the emissions of organic compounds classified by the US EPA as air toxics and include 2,2,4 trimethylpentane, benzene, toluene, ethylbenzene, m-, p- and o-xylene, formaldehyde, acetaldehyde and methylethyl ketone. Emission rates of 2,2,4 trimethylpentane, toluene, ethylbenzene, m-, p- and o-xylene decreased more than 90% for B50, B100 and B100T blends; decreases in emission rates of benzene, formaldehyde and acetaldehyde were more modest, producing values between 23 and 67%, and methyl ethyl ketone showed decreases not exceeding 7% for the studied biodiesel blends. PAHs emission rates were reduced by 66% for B50, 84% for B100, and by 89% for B100T. The overall emissions of toxic organic compounds were calculated and expressed as benzene equivalents. The largest contributors of toxic risk were found to be formaldehyde and acetaldehyde. Reductions in formaldehyde emissions were 23% for B50 and 42% for B100 soybean, and 40% for B100T beef tallow compared to B0. Similarly, acetaldehyde reductions were 34% for B50 and 53% for B100 soybean biodiesel and 42% for B100T beef tallow biodiesel.

Magara-Gomez, Kento T.; Olson, Michael R.; Okuda, Tomoaki; Walz, Kenneth A.; Schauer, James J.

2012-04-01

371

Proceedings of the 1999 international joint power generation conference (FACT-vol. 23). Volume 1: Fuels and combustion technologies; Gas turbines; and Nuclear engineering  

Microsoft Academic Search

Papers are arranged under the following topical sections: Gas turbine combustion; Advanced energy conversion; Low NOx solutions; Burner developments; Alternative fuels combustion; Advanced energy conversion technologies; Numerical modeling of combustion; Fluidized bed combustion; Coal combustion; Combustion research; Gasification systems; Mercury emissions; Highly preheated air combustion; Selective catalytic reduction; Special topics in combustion research; Gas turbines and advanced energy; and How

S. R. Jr. Penfield; N. A. Moussa

1999-01-01

372

Oxy-combustion of pulverized coal : modeling of char combustion kinetics.  

SciTech Connect

In this study, char combustion of pulverized coal under oxy-fuel combustion conditions was investigated on the basis of experimentally observed temperature-size characteristics and corresponding predictions of numerical simulations. Using a combustion-driven entrained flow reactor equipped with an optical particle-sizing pyrometer, combustion characteristics (particle temperatures and apparent size) of pulverized coal char particles was determined for combustion in both reduced oxygen and oxygen-enriched atmospheres with either a N{sub 2} or CO{sub 2} bath gas. The two coals investigated were a low-sulfur, high-volatile bituminous coal (Utah Skyline) and a low-sulfur subbituminous coal (North Antelope), both size-classified to 75-106 {micro}m. A particular focus of this study lies in the analysis of the predictive modeling capabilities of simplified models that capture char combustion characteristics but exhibit the lowest possible complexity and thus facilitate incorporation in existing computational fluid dynamics (CFD) simulation codes. For this purpose, char consumption characteristics were calculated for char particles in the size range 10-200 {micro}m using (1) single-film, apparent kinetic models with a chemically 'frozen' boundary layer, and (2) a reacting porous particle model with detailed gas-phase kinetics and three separate heterogeneous reaction mechanisms of char-oxidation and gasification. A comparison of model results with experimental data suggests that single-film models with reaction orders between 0.5 and 1 with respect to the surface oxygen partial pressure may be capable of adequately predicting the temperature-size characteristics of char consumption, provided heterogeneous (steam and CO{sub 2}) gasification reactions are accounted for.

Shaddix, Christopher R.; Haynes, Brian S. (University of Sydney, Sydney, Australia); Geier, Manfred

2010-09-01

373

Oxy-combustion of pulverized coal : modeling of char-combustion kinetics.  

SciTech Connect

In this study, char combustion of pulverized coal under oxy-fuel combustion conditions was investigated on the basis of experimentally observed temperature-size characteristics and corresponding predictions of numerical simulations. Using a combustion-driven entrained flow reactor equipped with an optical particle-sizing pyrometer, combustion characteristics (particle temperatures and apparent size) of pulverized coal char particles was determined for combustion in both reduced oxygen and oxygen-enriched atmospheres with either a N{sub 2} or CO{sub 2} bath gas. The two coals investigated were a low-sulfur, high-volatile bituminous coal (Utah Skyline) and a low-sulfur subbituminous coal (North Antelope), both size-classified to 75-106 {micro}m. A particular focus of this study lies in the analysis of the predictive modeling capabilities of simplified models that capture char combustion characteristics but exhibit the lowest possible complexity and thus facilitate incorporation in existing computational fluid dynamics (CFD) simulation codes. For this purpose, char consumption characteristics were calculated for char particles in the size range 10-200 {micro}m using (1) single-film, apparent kinetic models with a chemically 'frozen' boundary layer, and (2) a reacting porous particle model with detailed gas-phase kinetics and three separate heterogeneous reaction mechanisms of char-oxidation and gasification. A comparison of model results with experimental data suggests that single-film models with reaction orders between 0.5 and 1 with respect to the surface oxygen partial pressure may be capable of adequately predicting the temperature-size characteristics of char consumption, provided heterogeneous (steam and CO{sub 2}) gasification reactions are accounted for.

Shaddix, Christopher R.; Haynes, Brian S. (University of Sydney, Sydney, Australia); Geier, Manfred

2010-09-01

374

Stratified combustion engine  

SciTech Connect

The method is described of operating an internal combustion engine having a cylinder with an inner wall. The method comprises admitting, adjacent to the inner wall of the cylinder, a quantity of substantially pure air in a spirally rapidly rotating layer and directing all of the quantity uniformly coaxially relative to the cylinder and toward and against only the adjacent inner wall of the cylinder, and held thereat by Coanda effect and centrifugal force. This is done while also admitting a quantity of fuel mixture in a non-rotating and non-turbulent manner between the layer of rotating pure air and the longitudinal axis of the cylinder, compressing the rotating pure air and the non-rotating fuel mixture simultaneously and firing the non-rotating fuel mixture and exhausting the products of combustion and pure air uniformly coaxially relative to the cylinder and only from a region adjacent to the inner wall and uniformly and completely from the inner wall.

Solheim, R.G.

1987-03-17

375

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...

376

Mild Combustion of Methane-Derived Fuel Mixtures: Natural Gas and Biogas  

Microsoft Academic Search

Mild combustion (also called diluted or flameless combustion) is an innovative combustion process able to strongly reduce pollutant emissions with respect to traditional combustion processes; it is characterized by high preheating of the combustion air and massive recycle of burned gases. While it is well known that mild combustion leads to lowering NOx emissions when pure fuels (such as methane)

Alessandro Effuggi; Davino Gelosa; Marco Derudi; Renato Rota

2008-01-01

377

Pressurized Fluidized Bed Combustion of Sewage Sludge  

Microsoft Academic Search

A conceptual design of an energy recovering system from sewage sludge was proposed. This system consists of a pressurized fluidized bed combustor, a gas turbine, and a heat exchanger for preheating of combustion air. Thermal efficiency was estimated roughly as 10-25%. In order to know the combustion characteristics of the sewage sludge under the elevated pressure condition, combustion tests of

Yoshizo Suzuki; Tomoyuki Nojima; Akihiko Kakuta; Hiroshi Moritomi

2004-01-01

378

Two-cycle internal combustion engine  

Microsoft Academic Search

An improved two-cycle internal combustion engine is described that provides for greater combustion efficiency given at relatively low fuel-air ratios and thus reduces exhaust emissions. The engine employs an electric ignition system and is characterized by a combustion recess inside the cylinder head which becomes gradually deeper in the direction of gas flow in the cylinder. A device for controlling

Onishi

1974-01-01

379

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

380

A fluidized-bed combustion process with inherent CO 2 separation; application of chemical-looping combustion  

Microsoft Academic Search

For combustion with CO2 capture, chemical-looping combustion has the advantage that no energy is lost for the separation of CO2. In chemical-looping combustion oxygen is transferred from the combustion air to the gaseous fuel by means of an oxygen carrier. The fuel and the combustion air are never mixed, and the gases from the oxidation of the fuel, CO2 and

Anders Lyngfelt; Bo Leckner; Tobias Mattisson

2001-01-01

381

Experimental Study on Preheated Air and Flue Gas Recirculation in Solid Waste Incineration  

Microsoft Academic Search

The application of high temperature air combustion in incineration of solid waste was investigated. The combustion with preheated diluted secondary combustion air had effectively more energy saving and NOX emission reduction, but required a sufficient amount of preheated secondary combustion air to save more energy than non-dilution condition. The minimum preheated secondary combustion air temperature of 15 and 17% oxygen

P. Suvarnakuta; S. Patumsawad; S. Kerdsuwan

2010-01-01

382

Regenerated internal combustion engine  

Microsoft Academic Search

A thermally regenerated four-stroke cycle internal combustion engine, is described comprising: a cold side cylinder, having: an intake valve located through cold side cylinder wall for drawing air into the cold side cylinder; an exhaust valve independently located through the cold side cylinder wall for emitting exhaust gases; and a cold side piston connected to a crank shaft through a

1986-01-01

383

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

384

Pulse combustion drying apparatus for particulate materials  

SciTech Connect

This patent describes a pulse jet combustion apparatus for the drying of particulate material of the type having: a combustion chamber having an air entry end, an exhaust end and a common longitudinal axis therebetween, an air inlet conduit coaxially connected to the air entry and thereof, a primary exhaust gas conduit coaxially connected to the exhaust end thereof and, a tailpipe coaxially connected to the end of the exhaust gas conduit for directing the exhaust gases past a locus of particulate material introduction and to a dried particulate receiving chamber. The improvements described here comprise: primary fuel nozzles mounted at the air entry end of the combustion chamber downstream of the air inlet conduit and positioned to direct combustible fuel to a common location on the longitudinal axis of the combustion chamber spaced a predetermined distance from the air entry end thereof.

Gray, R.R.; Marguth, V.M.

1987-01-20

385

Mild Combustion  

Microsoft Academic Search

The Mild Combustion is characterized by both an elevated temperature of reactants and low temperature increase in the combustion process. These features are the results of several technological demands coming from different application fields. This review paper aims to collect information which could be useful in understanding the fundamentals and applications of Mild Combustion. The information in this field are

Antonio Cavaliere; Mara de Joannon

2004-01-01

386

Fluidized bed combustion of coal  

NASA Astrophysics Data System (ADS)

The effect of various parameters on combustion efficiency, desulfurization efficiency and NO emission in fluidized bed combustion of coal were investigated by using two test combustors whose sectional areas were 200 mm and 500 mm square. It has been revealed that by employing two-stage combustion and setting the primary air ratio, secondary air injection height and other parameters to optimum levels, NO emission can be greatly reduced while barely impairing combustion efficiency or desulfurization efficiency. Also, NO emission of less than 50 ppm and desulfurization efficiency of as high as 93% were achieved. These results have ensured good prospects for the development of a coal combustion boiler system which can satisfy the strictest environmental protection regulations, without installing special desulfurization and de-NO(X) facilities.

Tatebayashi, J.; Okada, Y.; Yano, K.; Takada, T.; Handa, K.

387

Internal combustion engine without connecting rods  

Microsoft Academic Search

This patent describes a reciprocating, multicylinder, internal combustion engine having an axially rotating power output crankshaft, the combination of: (a) a plurality of combustion chambers in side-by-side parallel arrangement, each chamber containing first means to admit a combustible fuel\\/air mixture and to exhaust the fumes of combustion; (b) a separate cylinder having an open end and a closed end forming

1989-01-01

388

Internal combustion engine without connecting rods  

Microsoft Academic Search

This patent describes a reciprocating, multicylinder, internal combustion engine having an axially rotating power output crankshaft, the combination of: (a) combustion chambers in side-by-side parallel arrangement, each chamber containing first means to admit a combustible fuel\\/air mixture and to exhaust the fumes of combustion; (b) a separate cylinder having an open end and a closed end forming part of each

1989-01-01

389

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

390

Device for improved combustion  

SciTech Connect

A device for improved combustion is described comprising: a tubular housing member having a first end and a second end, the first and second ends each having a circular opening therethrough; a combustion chamber disposed about the second end of the-tubular-housing member; a first conduit member extending from the first end of the tubular housing member and in fluid communication with the circular opening in the first end of the tubular housing member so as to allow the passage of air therethrough; a second conduit member axially disposed within the first conduit member and extending through the first conduit member and through the tubular housing member to the circular opening the second end of the tubular housing member so as to allow the passage of fuel therethrough; means for effecting turbulence in the air passing through the tubular housing member; means for effecting turbulence in the fuel passing through the second conduit member; means for intermixing and emitting the turbulent air and the fuel in a mushroom shaped configuration with the turbulent air surrounding the mushroom shaped configuration so as to substantially eliminate noxious waste gases as by-product of combustion of the air and fuel mixture.

Polomchak, R.W.; Yacko, M.

1988-03-08

391

Coal combustion system  

DOEpatents

In a coal combustion system suitable for a gas turbine engine, pulverized coal is transported to a rich zone combustor and burned at an equivalence ratio exceeding 1 at a temperature above the slagging temperature of the coal so that combustible hot gas and molten slag issue from the rich zone combustor. A coolant screen of water stretches across a throat of a quench stage and cools the combustible gas and molten slag to below the slagging temperature of the coal so that the slag freezes and shatters into small pellets. The pelletized slag is separated from the combustible gas in a first inertia separator. Residual ash is separated from the combustible gas in a second inertia separator. The combustible gas is mixed with secondary air in a lean zone combustor and burned at an equivalence ratio of less than 1 to produce hot gas motive at temperature above the coal slagging temperature. The motive fluid is cooled in a dilution stage to an acceptable turbine inlet temperature before being transported to the turbine.

Wilkes, Colin (Lebanon, IN); Mongia, Hukam C. (Carmel, IN); Tramm, Peter C. (Indianapolis, IN)

1988-01-01

392

Development of combustion data to utilize low-Btu gases as industrial process fuels: modification of flame characteristics. Project 61041 quarterly report, 1 January31 March 1980  

Microsoft Academic Search

This program consists of an experimental program to determine the burner modifications that will yield suitable flame characteristics and shapes with oxygen-blown gases manufactured from coal. Experiments will also be conducted to evaluate methods of enchancing the flame characteristics of manufactured gases from air-blown gasifiers. Progress to date includes a partial completion of the oxygen-enrichment system, preparation of the furnace

1980-01-01

393

Development of combustion data to utilize low-Btu gases as industrial process fuels: modification of flame characteristics. Project 61041 quarterly report, October 1December 31, 1979  

Microsoft Academic Search

This program consists of an experimental program to determine the burner modifications that will yield suitable flame characteristics and shapes with oxygen-blown gases manufactured from coal. Experiments will also be conducted to evaluate methods of enhancing the flame characteristics of manufactured gases from air-blown gasifiers. Progress to date includes design of, and requesting quotations on, the oxygen-enrichment piping, preparation of

1980-01-01

394

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

395

Multistage combustion method for inhibiting formation of nitrogen oxides  

Microsoft Academic Search

A method is disclosed, comprising injecting a primary fuel and air into a furnace to burn the fuel and form a first-stage combustion zone, the fuel being diluted with surrounding combustion gas and the air being supplied at a rate in excess of the stoichiometric rate required for the combustion of the fuel, and injecting a secondary fuel into the

N. Okigami; H. Hayasaka; Y. Sekiguchi; H. Tamuya

1983-01-01

396

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

397

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

398

Spontaneous ignition characteristics of gaseous hydrocarbon-air mixtures  

NASA Technical Reports Server (NTRS)

Experiments are conducted to determine the spontaneous ignition delay times of gaseous propane, kerosine vapor, and n-heptane vapor in mixtures with air, and oxygen-enriched air, at atmospheric pressure. Over a range of equivalence ratios from 0.2 to 0.8 it is found that ignition delay times are sensibly independent of fuel concentration. However, the results indicate a strong dependence of delay times on oxygen concentration. The experimental data for kerosine and propane demonstrate very close agreement with the results obtained previously by Mullins and Lezberg respectively.

Freeman, G.; Lefebvre, A. H.

1984-01-01

399

Promoted Combustion of Metals in a High-Pressure, Flowing Oxygen Environment  

NASA Technical Reports Server (NTRS)

Traditional promoted combustion testing has used 0.125 inch diameter samples that are ignited in a pressurized, oxygen-enriched environment. Many years of testing this sample size have yielded useful data regarding threshold pressure, or the minimum oxygen pressure required to support self-sustained combustion. However, when a material is tested in a flowing system, the threshold pressure changes. White Sands Test Facility has developed a test system to burn samples in flowing gaseous oxygen. Current sample configurations are 0.5 inch diameter rods and 1.25 inch diameter pipes with pressures ranging up to 2000 psi and gas velocities reaching 200 ft/s. This paper describes the test apparatus, modifications made as the result of a fire, and a description of the tests currently being performed.

Maes, M. J.; Stoltzfus, J. M.

2001-01-01

400

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

401

Mechanisms of Exhaust Pollutants and Plume Formation in Continuous Combustion.  

National Technical Information Service (NTIS)

The investigation of exhaust pollutant and plume formation in continuous combustion is a combined analytical and experimental study of turbulent, backmixed combustion in gas turbines. Experiments are being conducted operating with premixed methane/air and...

G. S. Samuelsen R. E. Peck

1975-01-01

402

Computational combustion  

Microsoft Academic Search

Progress in the field of computational combustion over the past 50 years is reviewed. Particular attention is given to those classes of models that are common to most system modeling efforts, including fluid dynamics, chemical kinetics, liquid sprays, and turbulent flame models. The developments in combustion modeling are placed into the time-dependent context of the accompanying exponential growth in computer

Charles K. Westbrook; Yasuhiro Mizobuchi; Thierry J. Poinsot; Phillip J. Smith; Jürgen Warnatz

2005-01-01

403

Computational Combustion  

Microsoft Academic Search

Progress in the field of computational combustion over the past 50 years is reviewed. Particular attention is given to those classes of models that are common to most system modeling efforts, including fluid dynamics, chemical kinetics, liquid sprays, and turbulent flame models. The developments in combustion modeling are placed into the time-dependent context of the accompanying exponential growth in computer

C K Westbrook; Y Mizobuchi; T J Poinsot; P J Smith; J Warnatz

2004-01-01

404

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.

405

Determining Heats of Combustion of Gaseous Hydrocarbons  

NASA Technical Reports Server (NTRS)

Enrichment-oxygen flow rate-ratio related to heat of combustion. Technique developed for determining heats of combustion of natural-gas samples. Based on measuring ratio m/n, where m is (volmetric) flow rate of oxygen required to enrich carrier air in which test gas flowing at rate n is burned, such that mole fraction of oxygen in combustion-product gases equals that in carrier air. The m/n ratio directly related to heats of combustion of saturated hydrocarbons present in natural gas.

Singh, Jag J.; Sprinkle, Danny R.; Puster, Richard L.

1987-01-01

406

Characterization and use of fluidized-bed-combustion coal ash  

Microsoft Academic Search

Fluidized-bed-combustion (FBC) technology will become more common as coal-combustion systems are retrofitted to meet air-emissions standards mandated by the 1991 Clean Air Act. FBC ash will present new challenges for coal-combustion by-product management. Calcium-based sorbents added to the combustion system of FBC make the properties of the resulting ash different from electric-utility fly ash. Recycling options, used to divert electric-utility

C. B. Behr-Andres; N. J. Hutzler

2009-01-01

407

Air diverter valve  

Microsoft Academic Search

An air diverter valve is described for use with an internal combustion engine having an emission control system including an exhaust system, an air pump, and a passage connecting the pump to the exhaust system for secondary air flow. The air diverter valve consists of a housing forming a pump discharge pressure chamber having an inlet port and a discharge

D. J. Pozniak; R. N. Siewert

1974-01-01

408

Catalytic Combustion of Syngas  

Microsoft Academic Search

The catalytic combustion of syngas\\/air mixtures over Pt has been investigated numerically in a channel-flow configuration using 2D steady and transient computer codes with detailed hetero-\\/homogeneous chemistry, transport, and heat transfer mechanisms in the solid. Simulations were carried out for syngas compositions with varying H2 and CO contents, pressures of 1 to 15 bar, and linear velocities relevant to power

John Mantzaras

2008-01-01

409

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) [Lacon, IL

2007-10-09

410

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

411

Combustion detector  

NASA Technical Reports Server (NTRS)

A device has been developed for generating a rapid response signal upon the radiation-emitting combustion reaction of certain gases in order to provide a means for the detection and identification of such reaction and concurrently discriminate against spurious signals. This combustion might be the first stage of a coal mine explosion process, and thereby this device could provide a warning of the impending explosion in time to initiate quenching action. This device has the capability of distinguishing between the light emitted from a combustion reaction and the light emitted by miners' lamps, electric lamps, welding sparks or other spurious events so that the quenching mechanism is triggered only when an explosion-initiating combustion occurs.

Trimpi, R. L.; Nealy, J. E.; Grose, W. L. (inventor)

1973-01-01

412

Combustion Physics.  

ERIC Educational Resources Information Center

Discusses how physics is used to improve the efficiency of combustion, pointing out that the interdisciplinary topic has applications to problems of real industrial relevance and practical value. (JN)

Jones, A. R.

1985-01-01

413

Removing aromatic and oxygenated VOCs from polluted air stream using Pt-carbon aerogels: assessment of their performance as adsorbents and combustion catalysts.  

PubMed

Two series of Pt-catalysts were prepared by impregnation or doping of carbon aerogels and different porous textures and Pt-dispersion were obtained. The performance of the samples in the elimination of organic compounds (VOCs) by adsorption and catalytic combustion was studied and compared with the characteristics of both the VOCs and the catalysts and the interactions between them. Toluene, xylenes and acetone were selected as representative aromatic or oxygenated VOCs. The adsorption of VOCs is favoured at room temperature in the case of meso/microporous materials, but at the higher catalytic reaction temperature, the micropores volume is more important. Adsorption and catalytic combustion occur simultaneously, and are both dependent on temperature, albeit in opposite directions. The combustion of aromatic compounds takes place at a lower temperature than that required for acetone combustion, so favouring the accumulation of adsorbed VOC, something that should be avoided to minimize risks. Catalytic performance improves with the contact time and is independent of oxygen content above 5% v/v, but declines significantly below this limit. PMID:21872395

Maldonado-Hódar, Francisco José

2011-10-30

414

COâ emission abatement in IGCC power plants by semiclosed cycles: Part B -- With air-blown combustion and COâ physical absorption  

Microsoft Academic Search

This paper analyzes the fundamentals of IGCC power plants with carbon dioxide removal systems, by a cycle configuration alternative to the one discussed in Part A (with oxygen-blown combustion). The idea behind this proposal is to overcome the major drawbacks of the previous solution (large oxygen consumption and re-design of the gas turbine unit), by means of a semiclosed cycle

P. Chiesa; G. Lozza

1999-01-01

415

Solvent and pressure influences on air separation of liquid crystalline triheptyl cellulose composite ethyl cellulose membranes  

SciTech Connect

Air separation of a cholesteric liquid crystalline triheptyl cellulose/ethyl cellulose (3/97) binary composite membrane prepared from tetrahydrofuran, chloroform, and dichloromethane solutions was studied at different pressure differences across the membrane by the variable volume method. With an increasing pressure difference in the range from 0.06 to 0.42 MPa, the flux and the oxygen concentration of the oxygen-enriched air through the membrane both increase. The air separation capability depends on the boiling point of the membrane-forming solvent and the membrane thickness. 15 refs., 4 figs., 1 tab.

Li, X.G.; Huang, M.R.; Lin, G.; Yang, P.C. (Tianjin Inst. of Textile Science and Technology (China))

1994-03-01

416

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

417

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

418

Method for automatically initiating in situ combustion for enhanced thermal recovery of hydrocarbons from a well  

Microsoft Academic Search

A method for initiating an in situ combustion operation for heating a well to recover petroleum from a subterranean reservoir in the well comprises lowering an elongated combustion chamber suspended from a hollow electrical cable with an air supply tube therearound which supplies electricity, fuel gas, and air to the combusion chamber, mixing an air-fuel mixture in the combustion chamber,

C. E. Howard; D. G. Calvin; R. W. Jr. Pitts

1979-01-01

419

Dynamics of deflagrations and reactive systems: Heterogeneous combustion; International Colloquium on Dynamics of Explosions and Reactive Systems, 12th, University of Michigan, Ann Arbor, July 23-28, 1989, Technical Papers  

Microsoft Academic Search

The present colloquium on the dynamics of explosions and reactive systems discusses combustion of dust-air mixtures, droplet combustion, combustion at solid and liquid surfaces, and combustion diagnostics. Attention is given to deflagration and detonation combustion of dust mixtures, experiments on unconfined dust-air flames, experimental measurement of the aerodynamic entrainability of dust deposits, and starch dust combustion characteristics in a closed

A. L. Kuhl; J.-C. Leyer; A. A. Borisov; W. A. Sirignano

1991-01-01

420

Plasma-augmented combustion behaviour in methanol  

Microsoft Academic Search

High-current discharge is studied between two electrodes where the filling medium is a mixture of methanol and air. Combustion is ignited by a 52 kJ discharge between two T-shaped electrodes. The combustion device consists of a 52 kJ capacitor bank, a discharge and combustion chamber and diagnostic systems. Current disruption has been observed at the moment of a change between the capacitive

E. A. Mehanna; M. A. Hassouba

2006-01-01

421

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

422

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

423

Dilute Oxygen Combustion; Phase I Final Report  

Microsoft Academic Search

A novel burner, in which fuel (natural gas) and oxidant (oxygen or air) are separately injected into a furnace, shows promise for achieving very low nitrogen oxide(s) (NOx) emissions for commercial furnace applications. The dilute oxygen combustion (DOC) burner achieves very low NOx through in-furnace dilution of the oxidant stream prior to combustion, resulting in low flame temperatures, thus inhibiting

H. M. Ryan; M. F. Riley; H. Kobayashi

1997-01-01

424

Dilute Oxygen Combustion; Phase 2 Final Report  

Microsoft Academic Search

A novel burner, in which fuel (natural gas) and oxidant (oxygen or air) are separately injected into a furnace, shows promise for achieving very low nitrogen oxide(s) (NOx) emissions for commercial furnace applications. The dilute oxygen combustion (DOC) burner achieves very low NOx through in-furnace dilution of the oxidant stream prior to combustion, resulting in low flame temperatures, thus inhibiting

H. M. Ryan; M. F. Riley; H. Kobayashi

2005-01-01

425

Gas Turbine Combustion Chambers with Film Evaporation.  

National Technical Information Service (NTIS)

The paper reports on an attempt to apply Meurer's film vaporization combustion method (M-method), originally developed for diesel motors, to the combustion chambers of gas turbines. (In the M-method, instead of distributing the fuel in the air, it is laid...

A. W. Hussmann

1968-01-01

426

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

427

Engine combustion chamber structure  

SciTech Connect

This patent describes a combustion chamber structure comprising an upper wall surface which is shaped like a pent-roof and into which an intake passage opens, a piston having on a head portion thereof a bulged portion conforming to the upper wall surface in shape, a first bowl portion which is formed substantially at the center of the bulged portion and which is substantially semispherical in shape, a pair of second bowl portions which respectively extend on opposite sides of the first bowl portion to the corresponding ends of the bulged portion of the piston along the edge of the bulged portion and are in communication with the first bowl portion, a swirl generating means which is adapted to generate a swirl of intake air in the combustion chamber when the engine load is light, and a spark plug disposed to substantially face the center of the first bowl portion from the upper wall surface; the swirl generating means being adapted to generate the swirl of intake air in a tangential direction in the combustion chamber; and the diameter of the first bowl portion being larger than the width of the second bowl portion.

Tanaka, H.

1988-09-13

428

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

429

Dilute Oxygen Combustion, Phase 2 Final Report.  

National Technical Information Service (NTIS)

A novel burner, in which fuel (natural gas) and oxidant (oxygen or air) are separately injected into a furnace, shows promise for achieving very low nitrogen oxide(s) (NOx) emissions for commercial furnace applications. The dilute oxygen combustion (DOC) ...

Y. Wang H. Kobayashi

2005-01-01

430

Ash characterization in laboratory-scale oxy-coal combustor  

EPA Science Inventory

Oxygen enriched coal (oxy-coal) combustion is a developing technology. During oxy-coal combustion, combustion air is separated and the coal is burned in a mixture of oxygen and recycled flue gas. The resulting effluent must be further processed before the C02 can be compressed, t...

431

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

432

Biofuels combustion.  

PubMed

This review describes major features of current research in renewable fuels derived from plants and from fatty acids. Recent and ongoing fundamental studies of biofuel molecular structure, oxidation reactions, and biofuel chemical properties are reviewed, in addition to combustion applications of biofuels in the major types of engines in which biofuels are used. Biofuels and their combustion are compared with combustion features of conventional petroleum-based fuels. Two main classes of biofuels are described, those consisting of small, primarily alcohol, fuels (particularly ethanol, n-butanol, and iso-pentanol) that are used primarily to replace or supplement gasoline and those derived from fatty acids and used primarily to replace or supplement conventional diesel fuels. Research efforts on so-called second- and third-generation biofuels are discussed briefly. PMID:23298249

Westbrook, Charles K

2013-01-01

433

Proceedings of the 1998 international joint power generation conference (FACT-Vol.22). Volume 1: Fuels and combustion technologies; Gas turbines; Environmental engineering; Nuclear engineering  

Microsoft Academic Search

Papers are arranged under the following topical sections: Fuels and combustion technologies; Low NOx burner applications; Low cost solutions to utility NOx compliance issues; Coal combustion--Retrofit experiences, low NOx, and efficiency; Highly preheated air combustion; Combustion control and optimization; Advanced technology for gas fuel combustion; Spray combustion and mixing; Efficient power generation using gas turbines; Safety issues in power industry;

A. Gupta; R. Natole; A. Sanyal; J. Veilleux

1998-01-01

434

STATIONARY SOURCE COMBUSTION: AN R/D UPDATE  

EPA Science Inventory

The paper discusses EPA/IERL-RTP R&D, underway since 1967, to advance combustion technology and the abatement and control of nitrogen oxides (NOx) and other combustion-generated pollutants from major stationary combustion sources. The primary air pollutants under consideration in...

435

Large-Scale Coherent Structures as Drivers of Combustion Instability  

Microsoft Academic Search

The role of flow coherent structures as drivers of combustion instabilities in a dump combustor was studied. Results of nonreacting tests in air and water flows as well as combustion experiments in a diffusion flame and dump combustor are discussed to provide insight into the generation process of large-scale structures in the combustor flow and their interaction with the combustion

K. C. SCHADOW; E. GUTMARK; T. P. PARR; D. M. PARR; K. J. WILSON; J. E. CRUMP

1989-01-01

436

Oxy-fuel combustion with integrated pollution control  

Microsoft Academic Search

An oxygen fueled integrated pollutant removal and combustion system includes a combustion system and an integrated pollutant removal system. The combustion system includes a furnace having at least one burner that is configured to substantially prevent the introduction of air. An oxygen supply supplies oxygen at a predetermine purity greater than 21 percent and a carbon based fuel supply supplies

Brian R. Patrick; Thomas Lilburn Ochs; Cathy Ann Summers; Danylo B. Oryshchyn; Paul Chandler Turner

2012-01-01

437

On-line measurement of heat of combustion  

Microsoft Academic Search

An experimental method for an on-line measurement of heat of combustion of a gaseous hydrocarbon fuel mixture of unknown composition is developed. It involves combustion of a test gas with a known quantity of air to achieve a predetermined oxygen concentration level in the combustion products. This is accomplished by a feedback controller which maintains the gas volumetric flow rate

S. K. Chaturvedi; H. Chegini

1988-01-01

438

Compliant Walled Combustion Devices.  

National Technical Information Service (NTIS)

Combustion devices described herein comprise a compliant combustion chamber wall or segment. The compliant segment deforms during combustion in the combustion chamber. Some devices may include a compliant wall configured to stretch responsive to pressure ...

H. Prahlad J. Helm R. E. Pelrine S. Oh S. E. Stanford

2005-01-01

439

Energy conservation in industrial operations - method and economics of improved combustion efficiencies. Topical report. Combustion-control systems for process heaters and boilers  

Microsoft Academic Search

The importance and applications of modern combustion control systems for retrofitting existing boilers and heaters to increase combustion efficiency are discussed. The conventionally used heater control system and its deficiencies are discussed in detail and the need for modern control systems is stressed. Modern combustion control systems are designed to provide safe and efficient combustion and desired air\\/fuel ratio, reducing

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

1979-01-01

440

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

441

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...

442

Preparation and characterization of nano- and non-nanoscale Co?O? spinels obtained from different methods and study of their performance in combustion of aromatics from polluted air-A comparison with Pt/?-Al?O? performance.  

PubMed

This article reports the development of oxidative precipitation (OP) method for synthesis of Co(3)O(4) as an environmental catalyst and comparison of its performance with that of obtained from conventional sol gel combustion (SG) method and industrial Pt/?-Al(2)O(3) in remediation of toluene from air. Catalytic studies were carried out in a fixed bed reactor at 100-350°C under atmospheric pressure. Co(3)O(4) (OP) showed the highest activity in combustion of toluene. The half conversion temperature of toluene (T(50%)) was 160, 258, and 229°C on Co(3)O(4) (OP), Co(3)O(4) (SG) and Pt/?-Al(2)O(3), respectively. The higher activity of Co(3)O(4) (OP) was ascribed to nanostructure and reducibility of catalytic sites at lower temperatures, approved by TPR results. The study confirmed that preparation method has a large influence on the chemical-physical properties and activity of the catalyst. The study indicated that oxidative precipitation method could be a promising method to synthesize environmental catalysts considering the simplicity and needless to calcine catalyst at higher temperatures. PMID:22755518

Hosseini, Seyedali; Niaei, Aligholi; Salari, Dariush

2012-01-01

443

40 CFR 1065.655 - Chemical balances of fuel, intake air, and exhaust.  

Code of Federal Regulations, 2010 CFR

...dilution air in diluted exhaust, x dil...dilution air in diluted exhaust, x dil...time-weighted mean values of combustion air humidity and...to produce actual combustion products per mole of dry (raw or diluted) exhaust....

2010-07-01

444

40 CFR 1065.655 - Chemical balances of fuel, intake air, and exhaust.  

Code of Federal Regulations, 2010 CFR

...dilution air in diluted exhaust, x dil...dilution air in diluted exhaust, x dil...time-weighted mean values of combustion air humidity and...to produce actual combustion products per mole of dry (raw or diluted) exhaust....

2009-07-01

445

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

446

Space Station Freedom combustion research  

NASA Technical Reports Server (NTRS)

Extended operations in microgravity, on board spacecraft like Space Station Freedom, provide both unusual opportunities and unusual challenges for combustion science. On the one hand, eliminating the intrusion of buoyancy provides a valuable new perspective for fundamental studies of combustion phenomena. On the other hand, however, the absence of buoyancy creates new hazards of fires and explosions that must be understood to assure safe manned space activities. These considerations - and the relevance of combustion science to problems of pollutants, energy utilization, waste incineration, power and propulsion systems, and fire and explosion hazards, among others - provide strong motivation for microgravity combustion research. The intrusion of buoyancy is a greater impediment to fundamental combustion studies than to most other areas of science. Combustion intrinsically heats gases with the resulting buoyant motion at normal gravity either preventing or vastly complicating measurements. Perversely, this limitation is most evident for fundamental laboratory experiments; few practical combustion phenomena are significantly affected by buoyancy. Thus, we have never observed the most fundamental combustion phenomena - laminar premixed and diffusion flames, heterogeneous flames of particles and surfaces, low-speed turbulent flames, etc. - without substantial buoyant disturbances. This precludes rational merging of theory, where buoyancy is of little interest, and experiments, that always are contaminated by buoyancy, which is the traditional path for developing most areas of science. The current microgravity combustion program seeks to rectify this deficiency using both ground-based and space-based facilities, with experiments involving space-based facilities including: laminar premixed flames, soot processes in laminar jet diffusion flames, structure of laminar and turbulent jet diffusion flames, solid surface combustion, one-dimensional smoldering, ignition and flame spread of liquids, drop combustion, and quenching of panicle-air flames. Unfortunately, the same features that make microgravity attractive for fundamental combustion experiments, introduce new fire and explosion hazards that have no counterpart on earth. For example, microgravity can cause broader flammability limits, novel regimes of flame spread, enhanced effects of flame radiation, slower fire detector response, and enhanced combustion upon injecting fire extinguishing agents, among others. On the other hand, spacecraft provide an opportunity to use 'fire-safe' atmospheres due to their controlled environment. Investigation of these problems is just beginning, with specific fire safety experiments supplementing the space based fundamental experiments listed earlier; thus, much remains to be done to develop an adequate technology base for fire and explosion safety considerations for spacecraft.

Faeth, G. M.

1992-01-01

447

Influence of vent air valve opening on combustion characteristics of a down-fired pulverized-coal 300 MWe utility boiler  

Microsoft Academic Search

Industrial experiments have been performed on a down-fired pulverized-coal 300MWe utility boiler with vent air valve opening of 100% and 40%. The gas temperature distribution along the primary air and coal mixture flow, gas temperature distribution in the furnace, and gas components such as O2, CO, CO2 and NOx in the near-wall region were measured for the first time. The

Zhengqi Li; Feng Ren; Jie Zhang; Xiaohui Zhang; Zhichao Chen; Lizhe Chen

2007-01-01

448

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

449

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...

450

Flow measurements in a model ramjet secondary combustion chamber  

Microsoft Academic Search

Experimental studies were conducted on a typical secondary combustion chamber of a ramjet to understand the influence of various inlet parameters such as primary nozzle configuration, secondary air injection angle, and flow Reynolds numbers on the secondary combustion chamber (SCC) performance. Cold flow studies were made with air as the flow medium for both primary and secondary jets followed by

Lazar T. Chittilapilly; S. Venkateswaran; P. J. Paul; H. S. Mukunda

1990-01-01

451

Investigation of combustion characteristics of Douglas fir hogged fuel  

Microsoft Academic Search

The initial results are presented of studies of the combustion characteristics of Douglas Fir bark (hogged fuel) as burned in a spreader-stoker experimental test facility. The project was funded by ERDA and attempts to determine combustion characteristics for fuels burned in controlled conditions. Independent variables include wood size, wood moisture content, underfire\\/overfire air ratios, and fuel to air ratios. The

Junge

1978-01-01

452

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...

453

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...

454

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.

455

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

456

Pressure-gain combustion  

SciTech Connect

Pulse combustion has been proposed for gas turbine applications in many early articles and more recently has been demonstrated to produce so-called ``pressure-gain`` in a small gas turbine. The basic concept is that the oscillatory combustion occurs as a constant-volume process, producing a gain in the stagnation pressure of air flowing through the combustor, rather than the pressure loss associated with conventional, steady combustion. If properly utilized, this pressure-gain could enhance simple-cycle gas turbine efficiency several percent, depending on the operating conditions. In addition, pulse combustors have demonstrated relatively low NO{sub x} pollutant levels in some applications. The combined potential for higher cycle efficiency and lower pollutant levels is the basis for the present investigation. Tests in progress at the Morgantown Energy Technology Center (METC) have considered a baseline pulse combustor configuration that has shown good oscillating performance, low NO{sub x} emissions, but disappointing results in terms of pressure-gain. However, a combination of numeric simulations and test data suggest that pressure-gain can be produced by a select combination of operating conditions and combustor geometry, but is especially sensitive to the combustor inlet geometry. Tests in progress will evaluate the effect of inlet geometry and operating pressure on both pollutant emissions and pressure-gain.

Richards, G.A.; Yip, J.; Gemmen, R.S.; Janus, M.C.; Norton, T. [USDOE Morgantown Energy Technology Center, WV (United States); Rogers, W.A. [EG and G Washington Analytical Services Center, Inc., Morgantown, WV (United States)

1993-11-01

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

NASA Astrophysics Data System (ADS)

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 observed in air masses that had been transported from Asia. The hydrocarbon composition of the air masses indicated that the highest CO levels were related to fossil fuel use. During the flights on 5 and 17 May and other days, the levels of several biomass-burning indicators increased with altitude. This was true for acetonitrile (CH3CN), methyl chloride (CH3Cl), the ratio of acetylene (C2H2) to propane (C3H8), and, on May 5, the percentage of particles measured by the particle analysis by laser mass spectrometry (PALMS) instrument that were attributed to biomass burning based on their carbon and potassium content. An ensemble of back-trajectories, calculated from the U.S. west coast over a range of latitudes and altitudes for the entire ITCT 2K2 period, showed that air masses from Southeast Asia and China were generally observed at higher altitudes than air from Japan and Korea. Emission inventories estimate the contribution of biomass burning to the total emissions to be low for Japan and Korea, higher for China, and the highest for Southeast Asia. Combined with the origin of the air masses versus altitude, this qualitatively explains the increase with altitude, averaged over the whole ITCT 2K2 period, of the different biomass-burning indicators.

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

2004-12-01