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1

Magnetohydrodynamics (MHD) Engineering Test Facility (ETF) 200 MWe power plant Conceptual Design Engineering Report (CDER)  

NASA Technical Reports Server (NTRS)

The reference conceptual design of the magnetohydrodynamic (MHD) Engineering Test Facility (ETF), a prototype 200 MWe coal-fired electric generating plant designed to demonstrate the commercial feasibility of open cycle MHD, is summarized. Main elements of the design, systems, and plant facilities are illustrated. System design descriptions are included for closed cycle cooling water, industrial gas systems, fuel oil, boiler flue gas, coal management, seed management, slag management, plant industrial waste, fire service water, oxidant supply, MHD power ventilating

1981-01-01

2

Magnetohydrodynamics (MHD) Engineering Test Facility (ETF) 200 MWe power plant  

SciTech Connect

A description and the design requirements for the 200 MWe (nominal) net output MHD Engineering Test Facility (ETF) Conceptual Design are presented. Performance requirements for the plant are identified and process conditions are indicated at interface stations between the major systems comprising the plant. Also included are the description, functions, interfaces and requirements for each of these major systems. This report integrates the latest information (1980 to 1981) from the MHD technology program with elements of a conventional steam electric power generating plant.

Rigo, H.S.; Bercaw, R.W.; Burkhart, J.A.; Mroz, T.S.; Bents, D.J.; Hatch, A.M.

1981-09-01

3

Parametric analysis of closed cycle magnetohydrodynamic (MHD) power plants  

NASA Technical Reports Server (NTRS)

A parametric analysis of closed cycle MHD power plants was performed which studied the technical feasibility, associated capital cost, and cost of electricity for the direct combustion of coal or coal derived fuel. Three reference plants, differing primarily in the method of coal conversion utilized, were defined. Reference Plant 1 used direct coal fired combustion while Reference Plants 2 and 3 employed on site integrated gasifiers. Reference Plant 2 used a pressurized gasifier while Reference Plant 3 used a ""state of the art' atmospheric gasifier. Thirty plant configurations were considered by using parametric variations from the Reference Plants. Parametric variations include the type of coal (Montana Rosebud or Illinois No. 6), clean up systems (hot or cold gas clean up), on or two stage atmospheric or pressurized direct fired coal combustors, and six different gasifier systems. Plant sizes ranged from 100 to 1000 MWe. Overall plant performance was calculated using two methodologies. In one task, the channel performance was assumed and the MHD topping cycle efficiencies were based on the assumed values. A second task involved rigorous calculations of channel performance (enthalpy extraction, isentropic efficiency and generator output) that verified the original (task one) assumptions. Closed cycle MHD capital costs were estimated for the task one plants; task two cost estimates were made for the channel and magnet only.

Owens, W.; Berg, R.; Murthy, R.; Patten, J.

1981-01-01

4

An economic analysis of the optimum stoichiometry for an early commercial MHD (magnetohydrodynamics) steam combined cycle power plant  

Microsoft Academic Search

The principal system studies of the performance of Combined Cycle Magnetohydrodynamics (MHD) Topped, Steam Bottomed power plants performed in the past have all utilized two stage combustion, wherein the primary combustor is fired fuel rich and combustion is completed after the gases have exited the MHD topping cycle and been cooled in a radiant furnace. The question addressed in this

J. N. Chapman; W. H. Boss

1990-01-01

5

MHD Power Generation  

ERIC Educational Resources Information Center

Explains the operation of the Magnetohydrodynamic (MHD) generator and advantages of the system over coal, oil or nuclear powered generators. Details the development of MHD generators in the United States and Soviet Union. (CP)

Kantrowitz, Arthur; Rosa, Richard J.

1975-01-01

6

Synopsis of Magnetohydrodynamic Power Generation  

NASA Technical Reports Server (NTRS)

Concise summary of magnetohydrodynamic (MHD) theory, history, and future trends presented in report. Worldwide research on MHD covered, and selected data from key research projects included. Magnetohydrodynamic generator produces electric current by passing fluid at high speed through strong magnetic field. Fluid ionized gas, plasma, or liquid metal. Magnetohydrodynamic generators offer potential for high efficiency, low power cost, and cleaner emissions.

Smith, J. L.

1986-01-01

7

MHD (magnetohydrodynamics) channel development  

NASA Astrophysics Data System (ADS)

Both Faraday and diagonal loaded MHD generators have larger power outputs at high wall temperatures for all generator sizes investigated. The increase in power at high T(sub w) diminishes with generator scale due to the drop in heat losses per unit volume as channels scale up. Boundary layer electrical detriments are volumetric effects and thus are not too different when scaled to larger MHD generators. Voltage drops and axial shorting effects dominate at low wall temperature while velocity defects become important at high wall temperature. An experiment to investigate the effects of cathode resegmentation on the performance of an MHD generator controlled the cathode resegmentation effect by using externally shorted cathodes and by minimizing internal shorting by eliminating the ash injection. The data obtained from this experiment provide insights into the current flow within the shorted regions. The data also provides a qualitative understanding of the effect of cathode resegmentation on the internal electric fields and current densities. Review of the 86-SEED-6 test results indicates that a significant portion of the 1A channel power shortfall is associated with loss of Hall voltage. The Hall voltage loss may be coupled to axial current leakage in the slag layer as demonstrated during the post-power conductivity measurement test. The results of oil-fired and the coal-fired generator tests from the CDIF are compared. The axial leakage effects are much more dominant in the latter. This shortfall is the result of the increased leakage.

1987-01-01

8

Magnetohydrodynamics (MHD) Engineering Test Facility (ETF) 200 MWe power plant. Design Requirements Document (DRD)  

NASA Technical Reports Server (NTRS)

A description and the design requirements for the 200 MWe (nominal) net output MHD Engineering Test Facility (ETF) Conceptual Design, are presented. Performance requirements for the plant are identified and process conditions are indicated at interface stations between the major systems comprising the plant. Also included are the description, functions, interfaces and requirements for each of these major systems. The lastest information (1980-1981) from the MHD technology program are integrated with elements of a conventional steam electric power generating plant.

Rigo, H. S.; Bercaw, R. W.; Burkhart, J. A.; Mroz, T. S.; Bents, D. J.; Hatch, A. M.

1981-01-01

9

Magnetohydrodynamics (MHD) Engineering Test Facility (ETF) 200 MWe power plant. Conceptual Design Engineering Report (CDER). Volume 4: Supplementary engineering data  

NASA Technical Reports Server (NTRS)

The reference conceptual design of the Magnetohydrodynamic Engineering Test Facility (ETF), a prototype 200 MWe coal-fired electric generating plant designed to demonstrate the commercial feasibility of open cycle MHD is summarized. Main elements of the design are identified and explained, and the rationale behind them is reviewed. Major systems and plant facilities are listed and discussed. Construction cost and schedule estimates, and identification of engineering issues that should be reexamined are also given. The latest (1980-1981) information from the MHD technology program are integrated with the elements of a conventional steam power electric generating plant. Supplementary Engineering Data (Issues, Background, Performance Assurance Plan, Design Details, System Design Descriptions and Related Drawings) is presented.

1981-01-01

10

Magnetohydrodynamics MHD Engineering Test Facility ETF 200 MWe power plant. Conceptual Design Engineering Report CDER. Volume 3: Costs and schedules  

NASA Technical Reports Server (NTRS)

The estimated plant capital cost for a coal fired 200 MWE electric generating plant with open cycle magnetohydrodynamics is divided into principal accounts based on Federal Energy Regulatory Commision account structure. Each principal account is defined and its estimated cost subdivided into identifiable and major equipment systems. The cost data sources for compiling the estimates, cost parameters, allotments, assumptions, and contingencies, are discussed. Uncertainties associated with developing the costs are quantified to show the confidence level acquired. Guidelines established in preparing the estimated costs are included. Based on an overall milestone schedule related to conventional power plant scheduling experience and starting procurement of MHD components during the preliminary design phase there is a 6 1/2-year construction period. The duration of the project from start to commercial operation is 79 months. The engineering phase of the project is 4 1/2 years; the construction duration following the start of the man power block is 37 months.

1981-01-01

11

An economic analysis of the optimum stoichiometry for an early commercial MHD (magnetohydrodynamics) steam combined cycle power plant  

SciTech Connect

The principal system studies of the performance of Combined Cycle Magnetohydrodynamics (MHD) Topped, Steam Bottomed power plants performed in the past have all utilized two stage combustion, wherein the primary combustor is fired fuel rich and combustion is completed after the gases have exited the MHD topping cycle and been cooled in a radiant furnace. The question addressed in this study is how-fuel-rich or, alternatively, what is the optimum stoichiometry for the plant in the sense of minimizing the Cost of Electricity (COE) Conclusions reached include: the overall plant efficiency increases monotonically for increased primary stoichiometry because the topping cycle mass flow increases and more power is generated by the topping cycle, less by the steam bottoming cycle; for each set of combustor pressure-oxygen enrichment values, there is a stoichiometry that minimizes capital cost; the primary stoichiometry that gives minimum levelized cost of electricity depends strongly upon coal cost -- higher coal justifies the more efficient, more expensive plants resulting from higher stoichiometries; the feasibility of operating the plant at primary stoichiometries at or higher than the 94% considered in this study needs experimental verification of secondary combustor performance. 21 refs., 50 figs., 1 tab.

Chapman, J.N.; Boss, W.H.

1990-05-01

12

Magnetohydrodynamic (MHD) channel corner seal  

DOEpatents

A corner seal for an MHD duct includes a compressible portion which contacts the duct walls and an insulating portion which contacts the electrodes, sidewall bars and insulators. The compressible portion may be a pneumatic or hydraulic gasket or an open-cell foam rubber. The insulating portion is segmented into a plurality of pieces of the same thickness as the electrodes, insulators and sidewall bars and aligned therewith, the pieces aligned with the insulator being of a different size from the pieces aligned with the electrodes and sidewall bars to create a stepped configuration along the corners of the MHD channel.

Spurrier, Francis R. (Pittsburgh, PA)

1980-01-01

13

Magnetohydrodynamics (MHD) engineering test facility (ETF) 200 MWe power plant: conceptual design engineering report (CDER). Volume 1. Executive summary  

SciTech Connect

The reference conceptual design of the MHD Engineering Test Facility (ETF), a prototype 200 MWe coal-fired electric generating plant designed to demonstrate the commercial feasibility of open cycle MHD is summarized. Main elements of the design are identified and explained, and the rationale behind them is reviewed. Major systems and plant facilities are listed and discussed. Construction cost and schedule estimates are presented and the engineering issues that should be reexamined are identified. This report integrates the latest (1980-1981) information from the MHD technology program with the elements of a conventional steam power electric generating plant. It is presented in five volumes.

Not Available

1981-09-01

14

Theoretical and experimental study of MHD (magnetohydrodynamic) micropump  

Microsoft Academic Search

This paper presents a novel micropump of which pumping mechanism is based upon magnetohydrodynamic (MHD) principles. MHD is the study of flow of electrically conducting liquids in electric and magnetic fields. Lorentz force is the pumping source of conductive, aqueous solutions in the MHD micropump. Conducting fluid in the microchannel of the MHD micropump is driven by Lorentz force in

Jaesung Jang; Seung S. Lee

2000-01-01

15

MHD-EMP analysis and protection. Technical report. [MHD-EMP (magnetohydrodynamic-electromagnetic pulse)  

SciTech Connect

A large nuclear detonation at altitudes of several hundred kilometers above the earth distorts the earth's magnetic field and produces a strong magnetohydrodynamic-electromagnetic pulse (MHD-EMP). MHD-EMP is similar to solar geomagnetic storms in its global and low frequency (less than 1 Hz) nature except that it can be more intense with a shorter duration. It will induce quasi-dc currents in long lines. The MHD-EMP induced currents may cause large voltage fluctuations and severe harmonic distortion in commercial electric power systems. Several MHD-EMP coupling models for predicting the induced current on a wide variety of conducting structures are described, various simulation concepts are summarized, and the results from several MHD-EMP tests are presented. To mitigate the effects of MHD-EMP on a facility, long conductors must be isolated from the building, and the commercial power harmonics and voltage swings must be addressed. It is found that facilities can be protected against MHD-EMP by using methods which are consistent with standard engineering practices. MHD-EMP Interaction Analysis, Power Line Model, MHD-EMP Protection Guidelines, Transformer Test.

Barnes, P.R.; Tesche, F.M.; McConnell, B.W.; Vance, E.F.

1993-09-01

16

Space Power MHD (magnetohydrodynamic) System: Third quarterly technical progress report, 1 November 1987-31 January 1988  

SciTech Connect

This progress report of the Space Power MHD System project presents the accomplishments during 1 November 1987 through 31 January 1988. The scope of work covered encompasses the definition of an MHD power system conceptual design and development plan (Task 1). Progress included the following: Subcontracts were issued to the MIT Plasma Fusion Center and the Westinghouse R and D Center. The performance of the 100 MW 500 sec. power system was optimized and the design concept finalized, including mass and energy balances. Mass and cost estimates were prepared. A design review was held at DOE/PETC. This also included the review of the technical issues definition and of the R and D Plan. Following the review, a final iteration on the conceptual design was initiated. Formulation of the R and D Plan was continued. Preparation of the Task 1 R and D Report was initiated. 12 figs.

Not Available

1988-03-15

17

Magnetohydrodynamics (MHD) Engineering Test Facility (ETF) 200 MWe power plant. Conceptual Design Engineering Report (CDER). Volume 1: Executive summary  

NASA Technical Reports Server (NTRS)

Main elements of the design are identified and explained, and the rationale behind them was reviewed. Major systems and plant facilities are listed and discussed. Construction cost and schedule estimates are presented, and the engineering issues that should be reexamined are identified. The latest (1980-1981) information from the MHD technology program is integrated with the elements of a conventional steam power electric generating plant.

1981-01-01

18

Explosively-driven magnetohydrodynamic (MHD) generator studies  

SciTech Connect

Plasma jet generators have been designed and tested which used an explosive driver and shocktube with a rectangular cross section that optimize the flow velocity and electrical conductivity. The latest in a series of designs has been tested using a reactive load to diagnose the electrical properties of the MHD generator/electromagnet combination. The results of these tests indicate that the plasma jet/MHD generator design does generate a flow velocity greater than 25 km/s and produces several gigawatts of pulsed power in a very small package size. A larger, new generator design is also presented.

Agee, F.J.; Lehr, F.M. [Phillips Lab., Kirtland AFB, NM (United States); Vigil, M.; Kaye, R. [Sandia National Labs., Albuquerque, NM (United States); Gaudet, J.; Shiffler, D. [New Mexico Univ., Albuquerque, NM (United States)

1995-08-01

19

Parametric study of potential early commercial MHD (magnetohydrodynamics) power plants: Task 3, Parametric variation of plant size  

SciTech Connect

This report is the final document reporting information developed in Task III of a Program Study of Potential Early Commercial MHD Power Plants under NASA Contract DEN 3-51. Task II consisted of the conceptual design of one of the reference plants analyzed in Task I. The Task II plant was identified as attractive and selected on the basis of Task I results. It employs oxygen enrichment of the combustion air and has a nominal plant capacity of 950 MW/sub e/. Task II permitted more detailed design analysis than that possible in the initial parametric analysis. Task III reported on in this document consisted of parametric performance and cost analyses of two plants of the same basic configuration as the plant studied in Task II but smaller in size. The two power plant sizes investigated in Task III correspond to nominal plant capacities of 200 MW/sub e/ and 500 MW/sub e/, respectively. The smallest plant size of 200 MW/sub e/ corresponds to the size presently specified for the Engineering Test Facility (ETF). In addition to providing cost estimates for each of the two downsized plants in Task III consistent with the cost analyses used in Task II, a capital cost estimate for a ''first of its kind'' power plant was developed for the smallest plant size of 200 MW/sub e/. This latter estimate served to identify the impact of applying learning curve factors to cost estimates of new technology items. Also, a detailed breakdown of the operating and maintenance cost of the larger Task II plant was a separate work subtask item of Task III. 8 refs., 52 figs., 36 tabs.

Hals, F.A.

1981-09-01

20

Magnetohydrodynamic power generation  

NASA Astrophysics Data System (ADS)

Experimental and theoretical research has been conducted to investigate phenomena expected to be important in the development of MHD power generation. The areas investigated were: Boundary layers and generator loss mechanisms, plasma nonuniformities and instabilities, investigation of rod electrodes, seed-slag interaction and the reactivity of coal, disk generators, and temperature diagnostic techniques for combustion MHD plasmas. Brief summaries of the principal results and their expected impact for large scale MHD generators are given: (1) Secondary flows driven by transverse Lorentz forces are predicted to be a major phenomenon in large-scale generators. We have studied this phenomenon by conducting experiments in a laboratory-scale facility in which a high magnetic interaction parameter for driving such secondary flows has been achieved by applying axial current and by maintaining low flow rates. The results of measurements of transverse velocities show that the resulting secondary flows consist of intense, large-scale vortices which convectively distort the cross-plane distribution of important plasma properties. (2) An experimental approach based on measurements of the phase difference of acoustic waves excited in an MHD generator has been successfully employed to detect changes caused by the magnetoacoustic interaction. Predictions for large-scale MHD generators, based upon this same theory, suggest that the possible detrimental effects of the magnetoacoustic interaction cannot be ignored, and must be given serious attention in the design of large-scale facilities.

Kruger, C. H.; Eustis, R. H.; Mitchner, M.; Self, S. A.; Nakamura, T.

1985-06-01

21

Methods for the Efficient Calculation of the (Mhd) Magnetohydrodynamic Stability Properties of Magnetically Confined Fusion Plasmas  

Microsoft Academic Search

A magnetohydrodynamic (MHD) model is applied to the problem of the stability of magnetically confined ther monuclear plasmas of interest in the pursuit of fusion power. Previous studies limited to two-dimensional con figurations are here generalized to three-dimensional toroidal plasmas. Using finite Fourier representations in the angle coordinates and finite hybrid elements in the radial direction, we solve the discretized

D. V. Anderson; W. A. Cooper; R. Gruber; S. Merazzi; U. Schwenn

1990-01-01

22

Nuclear reactor magnetohydrodynamic power generator for directed energy weapons  

Microsoft Academic Search

The SDI electrical power requirements for directed energy weapons (DEW) may range from tens of megawatts to over hundreds of megawatts. For this application, where the power requirement is continuous for a period to time ranging from tens to hundreds or thousands of seconds, nuclear magnetohydrodynamic (MHD) power generation provides an attractive method for producing the required power levels. The

Daniel W. Swallom

1987-01-01

23

MHD I: Demonstrate Magnetohydrodynamic Propulsion in a Minute  

NSDL National Science Digital Library

Remember the silent caterpillar drive from the movie The Hunt for Red October? The caterpillar drive was a fictional magnetohydrodynamic propulsion system. Magnetohydrodynamic (MHD) propulsion is a means of using electrical current, instead of a noisy propeller, to push a ship through the water. Surprisingly enough, a working example of this futuristic drive system is quite easy to build. Assuming that you've got the materials handy, you can build one in about a minute. This is a great student project or a good demonstration.

2008-10-24

24

Magnetohydrodynamics (MHD) Engineering Test Facility (ETF) 200 MWe power plant. Conceptual Design Engineering Report (CDER). Volume 2: Engineering. Volume 3: Costs and schedules  

NASA Technical Reports Server (NTRS)

Engineering design details for the principal systems, system operating modes, site facilities, and structures of an engineering test facility (ETF) of a 200 MWE power plant are presented. The ETF resembles a coal-fired steam power plant in many ways. It is analogous to a conventional plant which has had the coal combustor replaced with the MHD power train. Most of the ETF components are conventional. They can, however, be sized or configured differently or perform additional functions from those in a conventional coal power plant. The boiler not only generates steam, but also performs the functions of heating the MHD oxidant, recovering seed, and controlling emissions.

1981-01-01

25

Magnetohydrodynamics (MHD) Engineering Test Facility (ETF) 200 MWe power plant. Conceptual Design Engineering Report (CDER). Volume 2: Engineering. Volume 3: Costs and schedules. Final Report  

SciTech Connect

Engineering design details for the principal systems, system operating modes, site facilities, and structures of an engineering test facility (ETF) of a 200 MWE power plant are presented. The ETF resembles a coal-fired steam power plant in many ways. It is analogous to a conventional plant which has had the coal combustor replaced with the MHD power train. Most of the ETF components are conventional. They can, however, be sized or configured differently or perform additional functions from those in a conventional coal power plant. The boiler not only generates steam, but also performs the functions of heating the MHD oxidant, recovering seed, and controlling emissions.

Not Available

1981-09-01

26

Solar-Driven Liquid-Metal MHD Generator:Magnetohydrodynamics appears to be an efficient way to convert solar radiation to electric power.  

National Technical Information Service (NTIS)

This citation summarizes a one-page announcement of technology available for utilization. A liquid-metal magnetohydrodynami (MHD) power generator wwth a solar oven as its heat source has the potential to produce electric power in at high efficiecy. A sola...

1982-01-01

27

Magnetohydrodynamics (MHD) Engineering Test Facility (ETF) 200 MWe power plant. Conceptual Design Engineering Report (CDER) supplement. Magnet system special investigations  

NASA Technical Reports Server (NTRS)

The results of magnet system special investigations listed below are summarized: 4 Tesla Magnet Alternate Design Study; 6 Tesla Magnet Manufacturability Study. The conceptual design for a 4 Tesla superconducting magnet system for use with an alternate (supersonic) ETF power train is described, and estimated schedule and cost are identified. The magnet design is scaled from the ETF 6 T Tesla design. Results of a manufacturability study and a revised schedule and cost estimate for the ETF 6 T magnet are reported. Both investigations are extensions of the conceptual design of a 6 T magnet system performed earlier as a part of the overall MED-ETF conceptual design described in Conceptual Design Engineering Report (CDER) Vol. V, System Design Description (SDD) 503 dated September, 1981, DOE/NASA/0224-1; NASA CR-165/52.

1981-01-01

28

Magnetohydrodynamics (MHD) Engineering Test Facility (ETF) 200-MWe power plant: Conceptual design engineering report (CDER). Volume II. Engineering; Volume III. Costs and schedules  

SciTech Connect

This report summarizes the reference conceptual design of the MHD Engineering Test Facility (ETF), a prototype 200 MWe coal-fired electric generating plant designed to demonstrate the commercial feasibility of open cycle MHD. Main elements of the design are identified and explained, and the rationale behind them is reviewed. Major systems and plant facilities are listed and discussed. The report also presents construction cost and schedule estimates, and identifies the engineering issues that should be reexamined. This report integrates the latest (1980-1981) information from the MHD technology program with the elements of a conventional steam power electric generating plant. The engineering information (volume II) is presented, and volume III (costs and schedules) is included as microfiche.

Not Available

1981-09-01

29

International Conference on MHD Electrical Power Generation, 7th, Massachusetts Institute of Technology, Cambridge, MA, June 16-20, 1980, Proceedings. Volumes 1, 2 & 3  

NASA Astrophysics Data System (ADS)

The first volume of this conference on magnetohydrodynamics (MHD) for electrical power generation covers: (1) MHD pilot plants; (2) MHD generator experiments and modeling; (3) the performance of various MHD generator types; (4) MHD channel design considerations; (5) MHD channel materials considerations; (6) MHD system components, heat recovery and emissions; and (7) MHD oxidizers and inverters. The second volume deals with (8) MHD system magnets and combustors; (9) MHD field, flow and chemical processes; (10) MHD fluid dynamics; (11) MHD electrical power plant design; (12) current transfer and diagnostics; and (13) MHD power plant systems considerations.

Dawson, A. M.; Overlan, D.

30

Energy Conversion Alternatives Study (ECAS), Westinghouse phase 1. Volume 9: Closed-cycle MHD. [energy conversion efficiency of electric power plants using magnetohydrodynamics  

NASA Technical Reports Server (NTRS)

A closed-cycle MHD system for an electric power plant was studied. It consists of 3 interlocking loops, an external heating loop, a closed-cycle cesium seeded argon nonequilibrium ionization MHD loop, and a steam bottomer. A MHD duct maximum temperature of 2366 K (3800 F), a pressure of 0.939 MPa (9.27 atm) and a Mach number of 0.9 are found to give a topping cycle efficiency of 59.3%; however when combined with an integrated gasifier and optimistic steam bottomer the coal to bus bar efficiency drops to 45.5%. A 1978 K (3100 F) cycle has an efficiency of 55.1% and a power plant efficiency of 42.2%. The high cost of the external heating loop components results in a cost of electricity of 21.41 mills/MJ (77.07 mills/kWh) for the high temperature system and 19.0 mills/MJ (68.5 mills/kWh) for the lower temperature system. It is, therefore, thought that this cycle may be more applicable to internally heated systems such as some futuristic high temperature gas cooled reactor.

Tsu, T. C.

1976-01-01

31

Energy Conversion Alternatives Study (ECAS), Westinghouse phase 1. Volume 8: Open-cycle MHD. [energy conversion efficiency and design analysis of electric power plants employing magnetohydrodynamics  

NASA Technical Reports Server (NTRS)

Electric power plant costs and efficiencies are presented for three basic open-cycle MHD systems: (1) direct coal fired system, (2) a system with a separately fired air heater, and (3) a system burning low-Btu gas from an integrated gasifier. Power plant designs were developed corresponding to the basic cases with variation of major parameters for which major system components were sized and costed. Flow diagrams describing each design are presented. A discussion of the limitations of each design is made within the framework of the assumptions made.

Hoover, D. Q.

1976-01-01

32

Pulse Detonation Rocket Magnetohydrodynamic Power Experiment  

NASA Technical Reports Server (NTRS)

The production of onboard electrical power by pulse detonation engines is problematic in that they generate no shaft power; however, pulse detonation driven magnetohydrodynamic (MHD) power generation represents one intriguing possibility for attaining self-sustained engine operation and generating large quantities of burst power for onboard electrical systems. To examine this possibility further, a simple heat-sink apparatus was developed for experimentally investigating pulse detonation driven MHD generator concepts. The hydrogen oxygen fired driver was a 90 cm long stainless steel tube having a 4.5 cm square internal cross section and a short Schelkin spiral near the head end to promote rapid formation of a detonation wave. The tube was intermittently filled to atmospheric pressure and seeded with a CsOH/methanol prior to ignition by electrical spark. The driver exhausted through an aluminum nozzle having an area contraction ratio of A*/A(sub zeta) = 1/10 and an area expansion ratio of A(sub zeta)/A* = 3.2 (as limited by available magnet bore size). The nozzle exhausted through a 24-electrode segmented Faraday channel (30.5 cm active length), which was inserted into a 0.6 T permanent magnet assembly. Initial experiments verified proper drive operation with and without the nozzle attachment, and head end pressure and time resolved thrust measurements were acquired. The exhaust jet from the nozzle was interrogated using a polychromatic microwave interferometer yielding an electron number density on the order of 10(exp 12)/cm at the generator entrance. In this case, MHD power generation experiments suffered from severe near-electrode voltage drops and low MHD interaction; i.e., low flow velocity, due to an inherent physical constraint on expansion with the available magnet. Increased scaling, improved seeding techniques, higher magnetic fields, and higher expansion ratios are expected to greatly improve performance.

Litchford, R. J.; Jones, J. E.; Dobson, C. C.; Cole, J. W.; Thompson, B. R.; Plemmons, D. H.; Turner, M. W.

2003-01-01

33

Magnetohydrodynamics (MHD) Engineering Test Facility (ETF) 200 MWe Power Plant. Conceptual Design Engineering Report (CDER). Volume V. Supplementary Engineering Data (Cont'D).  

National Technical Information Service (NTIS)

The reference conceptual design of the MHD Engineering Test Facility (ETF), a prototype 200 MWe coal-fired electric generating plant designed to demonstrate the commercial feasibility of open-cycle MHD is summarized. Detailed system design descriptions ar...

1981-01-01

34

Magnetohydrodynamic\\/steam power plant modeling and control  

Microsoft Academic Search

A dynamic power-flow simulation of an overall magnetohydrodynamic (MHD)\\/steam electrical power generating plant is developed. Time domain solutions to the set of system equations are given. Several control configurations are applied to the system and their effects on system dynamic response are presented. The overall combined-cycle system model utilizes an input-output characterization of the Combustor\\/Nozzle\\/Channel\\/Diffuser. This characterization is developed from

J. D. Aspnes; D. A. Pierre

1978-01-01

35

The Galerkin boundary node method for magneto-hydrodynamic (MHD) equation  

NASA Astrophysics Data System (ADS)

In this research, a variational reformulation for magneto-hydrodynamic (MHD) problem is derived. Existence and uniqueness of the weak solution are discussed. The Galerkin boundary node method is a boundary meshless method which uses MLS basis functions to approximate solution of problems. This paper tries to apply this method for a variational form of the magneto-hydrodynamic (MHD) problem. Numerical experiments reveal that the method is effective and convenient for this problem.

Tatari, Mehdi; Ghasemi, Fatemeh

2014-02-01

36

Ways to improve MHD power plants and prospects of their application  

Microsoft Academic Search

The characteristics of magnetohydrodynamic (MHD) power plants, their modification possibilities, and their areas of application are analyzed. The analysis is based on the status of available power plants including steam turbine and combined-cycle steam\\/gas power plants. Conventional MHD power plants, based on existing technical solutions and various novel schemes are discussed. The main directions for improvement of energy conversion efficiency

V. M. Batenin; S. I. Pistchikov; J. N. Sokolov; E. M. Shelkov

1991-01-01

37

Part-load studies on subsonic and supersonic MHD/steam power plants  

SciTech Connect

This paper presents results from an ongoing series of investigations to establish optimum methods of operation for commercial scale (approximately 500 MWe) magnetohydrodynamics (MHD)/steam power plants. With this as the goal, part load performance estimates were made for two nearly identical 500 MWe MHD/steam power plants, one using a subsonic MHD channel and the other using a supersonic MHD channel. Analysis was concentrated for the load range from 100 to 75 percent of rated capacity.

Murthy, M.L.R.; Cutting, J.C.; Owens, W.R.; Sheth, P.R.

1984-08-01

38

Characteristics of a magnetohydrodynamic electrical power generator using convexly divergent channel  

NASA Astrophysics Data System (ADS)

We describe a magnetohydrodynamic (MHD) electrical power generator equipped with a convexly divergent channel, as determined through shock-tunnel-based experiments. The slight enhancement in a MHD channel divergence upstream provides boundary layer relief in a MHD flow decelerated by a retarding Lorentz force. Despite the present approach being simple and requiring a relatively minor modification of the MHD channel profile, the quality of MHD power-generating plasma and the energy conversion efficiency are improved compared to those from a previous linearly divergent channel; an excessive increase in static pressure is suppressed and a Hall field is enhanced, whereby notably high isentropic efficiency is achieved.

Murakami, Tomoyuki; Okuno, Yoshihiro

2010-03-01

39

Simulation of a seawater MHD power generation system  

NASA Astrophysics Data System (ADS)

MHD (magnetohydrodynamics) power generation systems are expected to become popular with the development of superconducting technology because of their low cost and high efficiency. MHD power generation directly utilizes electromotive force, which arises when seawater crosses a magnetic field. The helical-type MHD generator is composed mainly of a helical partition board and electrodes, which include a cathode pipe on the exterior of the generator and an anode rod in the interior. Elementary research on a helical-type MHD power generation system has started at Kobe University, and a numerical simulation of the system has been carried out by FEM (Finite Element Method) at the National Institute for Materials Science. By comparing the simulation results with the theoretical and experimental results, we found that the proposed method is valid for simulating the MHD power generation system.

Liu, Xiaojun; Kiyoshi, Tsukasa; Takeda, Minoru

2006-05-01

40

Economic analysis of the optimum stoichiometry for an early commercial MHD steam combined cycle power plant.  

National Technical Information Service (NTIS)

The principal system studies of the performance of Combined Cycle Magnetohydrodynamics (MHD) Topped, Steam Bottomed power plants performed in the past have all utilized two stage combustion, wherein the primary combustor is fired fuel rich and combustion ...

J. N. Chapman W. H. Boss

1990-01-01

41

Preliminary analysis of MHD retrofit for the Colstrip power plant  

SciTech Connect

The US DOE Office of Magnetohydrodynamics has established a development program to demonstrate the commercial feasibility of magnetohydrodynamic power generation through the operation of an Engineering Test Facility (ETF). Two MHD power system designs as candidates for the Engineering Test Facility are presented. The two system designs involve open-cycle MHD power trains retrofitted to the coal fired Colstrip power plant owned by the Montana Power Company. Under retrofit operation, the MHD topping cycle generates electric power from hot (4500/sup 0/F) coal combustion gas flowing through the MHD generator, and produces steam for the Colstrip plant from heat recovered from combustion gas leaving the MHD generator. The Colstrip plant acts as a steam bottoming cycle, receiving a portion of its steam supply from the MHD heat recovery system. A portion of the plant steam supply is also obtained from the original Colstrip boiler. A retrofit facility reduces construction time and cost from what would be required for an entirely new MHD test facility by using not only the available steam cycle equipment, but most of the supplemental facilities as well. One retrofit system employs an oxygen enriched, direct fired MHD power train in which the combustion oxidizer is a mixture of air and oxygen preheated to a moderate temperature (1100/sup 0/F). The preheat is obtained in a recuperative type heat exchanger. The other retrofit system uses an MHD power train with nonenriched air preheated to a high temperature (2500/sup 0/F) as the oxidizer; preheat is obtained in a regenerative type heat exchanger subsystem that is fired separately with oil. A preliminary design and cost estimate for each retrofit system is presented. (WHK)

Not Available

1980-06-01

42

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

43

Integrated Pulse Detonation Propulsion and Magnetohydrodynamic Power  

NASA Technical Reports Server (NTRS)

The prospects for realizing an integrated pulse detonation propulsion and magnetohydrodynamic (MHD) power system are examined. First, energy requirements for direct detonation initiation of various fuel-oxygen and fuel-air mixtures are deduced from available experimental data and theoretical models. Second, the pumping power requirements for effective chamber scavenging are examined through the introduction of a scavenging ratio parameter and a scavenging efficiency parameter. A series of laboratory experiments were carried out to investigate the basic engineering performance characteristics of a pulse detonation-driven MHD electric power generator. In these experiments, stoichiometric oxy-acetylene mixtures seeded with a cesium hydroxide/methanol spray were detonated at atmospheric pressure in a 1-m-long tube having an i.d. of 2.54 cm. Experiments with a plasma diagnostic channel attached to the end of the tube confirmed the attainment of detonation conditions (p(sub 2)/p(sub 1) approx. 34 and D approx. 2,400 m/sec) and enabled the direct measurement of current density and electrical conductivity (=6 S/m) behind the detonation wave front. In a second set of experiments, a 30-cm-long continuous electrode Faraday channel, having a height of 2.54 cm and a width of 2 cm, was attached to the end of the tube using an area transition duct. The Faraday channel was inserted in applied magnetic fields of 0.6 and 0.95 T. and the electrodes were connected to an active loading circuit to characterize power extraction dependence on load impedance while also simulating higher effective magnetic induction. The experiments indicated peak power extraction at a load impedance between 5 and 10 Ohm. The measured power density was in reasonable agreement with a simple electrodynamic model incorporating a correction for near-electrode potential losses. The time-resolved thrust characteristics of the system were also measured, and it was found that the MHD interaction exerted a negligible influence on system thrust and that the measured I(sub sp) of the system (200 sec) exceeded that computed for an equivalent nozzleless rocket (120 sec).

Litchford, R. J.; Lyles, Garry M. (Technical Monitor)

2001-01-01

44

Momentum Transport in DIII-D Discharges with and Without Magnetohydrodynamics (MHD) Activity  

SciTech Connect

Two phases of a DIII-D discharge with and without magnetohydrodynamics (MHD) activity are analysed using ONETWO code. The toroidal momentum flux is extracted from experimental data and compared with the predictions by neoclassical theory, Gyro-Landau fluid transport model (GLF23) and Multi-Mode model (MMM95). It is found that without MHD activities GLF23 and MMM95 provide a reasonable description while with MHD activity no model alone can fully describe the experimental momentum flux. For the phase with MHD activity a simple model of resonant magnetic drag is tested and it cannot fully explain the plasma slowing down observed in experiment.

Park, Jin Myung [ORNL

2009-02-01

45

Ways to improve MHD power plants and prospects of their application  

NASA Astrophysics Data System (ADS)

The characteristics of magnetohydrodynamic (MHD) power plants, their modification possibilities, and their areas of application are analyzed. The analysis is based on the status of available power plants including steam turbine and combined-cycle steam/gas power plants. Conventional MHD power plants, based on existing technical solutions and various novel schemes are discussed. The main directions for improvement of energy conversion efficiency are presented, together with ways to modify MHD systems so as to reduce their capital costs. The conclusion is that MHD power plants could be competitive with most advanced power generation technologies.

Batenin, V. M.; Pistchikov, S. I.; Sokolov, J. N.; Shelkov, E. M.

1991-05-01

46

Improvement of isentropic efficiency of a magnetohydrodynamic power generator by radio-frequency preionization  

SciTech Connect

We describe the effect of a radio-frequency (rf) power application on the performance of a magnetohydrodynamic (MHD) electrical power generator, as determined through shock-tunnel-based experiments and quasi-three-dimensional numerical simulations. The temporal plasma-fluid behavior, the one-dimensional plasma-fluid structure, the enthalpy-entropy diagram, the quality of the energy conversion efficiency, and the energy flow in the power-generating system are investigated. Preionization assistance by a small amount of rf power drastically changes the entire MHD power-generating system; the MHD extraction length is considerably extended and the isentropic efficiency is significantly improved.

Murakami, Tomoyuki; Okuno, Yoshihiro [Department of Energy Sciences, Tokyo Institute of Technology, 4259-G3-38 Nagatsuta, Midori-ku, Yokohama 226-8502 (Japan)

2009-01-15

47

Laser-powered MHD generators for space application  

SciTech Connect

Magnetohydrodynamic (MHD) energy conversion systems of the pulsed laser-supported detonation (LSD) wave, plasma MHD, and liquid-metal MHD (LMMHD) types are assessed for their potential as space-based laser-to-electrical power converters. These systems offer several advantages as energy converters relative to the present chemical, nuclear, and solar devices, including high conversion efficiency, simple design, high-temperature operation, high power density, and high reliability. Of these systems, the Brayton cycle liquid-metal MHD system appears to be the most attractive. The LMMHD technology base is well established for terrestrial applications, particularly with regard to the generator, mixer, and other system components. However, further research is required to extend this technology base to space applications and to establish the technology required to couple the laser energy into the system most efficiently. Continued research on each of the three system types is recommended.

Jalufka, N.W.

1986-10-01

48

Laser-powered MHD generators for space application  

NASA Technical Reports Server (NTRS)

Magnetohydrodynamic (MHD) energy conversion systems of the pulsed laser-supported detonation (LSD) wave, plasma MHD, and liquid-metal MHD (LMMHD) types are assessed for their potential as space-based laser-to-electrical power converters. These systems offer several advantages as energy converters relative to the present chemical, nuclear, and solar devices, including high conversion efficiency, simple design, high-temperature operation, high power density, and high reliability. Of these systems, the Brayton cycle liquid-metal MHD system appears to be the most attractive. The LMMHD technology base is well established for terrestrial applications, particularly with regard to the generator, mixer, and other system components. However, further research is required to extend this technology base to space applications and to establish the technology required to couple the laser energy into the system most efficiently. Continued research on each of the three system types is recommended.

Jalufka, N. W.

1986-01-01

49

Integrated Pulse Detonation Propulsion and Magnetohydrodynamic Power  

NASA Technical Reports Server (NTRS)

The prospects for realizing an integrated pulse detonation propulsion and magnetohydrodynamic (MHD) power system are examined. First, energy requirements for direct detonation initiation of various fuel-oxygen and fuel-air mixtures are deduced from available experimental data and theoretical models. Second, the pumping power requirements for effective chamber scavenging are examined through the introduction of a scavenging ratio parameter and a scavenging efficiency parameter. A series of laboratory experiments were carried out to investigate the basic engineering performance characteristics of a pulse detonation-driven MHD electric power generator. In these experiments, stoichiometric oxy-acetylene mixtures seeded with a cesium hydroxide/methanol spray were detonated at atmospheric pressure in a 1-m-long tube having an i.d. of 2.54 cm. Experiments with a plasma diagnostic channel attached to the end of the tube confirmed the attainment of detonation conditions (p2/p1 approximately 34 and D approximately 2,400 m/sec) and enabled the direct measurement of current density and electrical conductivity (approximately = 6 S/m) behind the detonation wave front, In a second set of experiments, a 30-cm-long continuous electrode Faraday channel, having a height of 2.54 cm and a width of 2 cm, was attached to the end of the tube using an area transition duct. The Faraday channel was inserted in applied magnetic fields of 0.6 and 0.95 T, and the electrodes were connected to an active loading circuit to characterize power extraction dependence on load impedance while also simulating higher effective magnetic induction. The experiments indicated peak power extraction at a load impedance between 5 and 10 Omega. The measured power density was in reasonable agreement with a simple electrodynamic model incorporating a correction for near-electrode potential losses. The time-resolved thrust characteristics of the system were also measured, and it was found that the NM interaction exerted a negligible influence on system thrust and that the measured I(sub sp) of the system (200 see) exceeded that computed for an equivalent nozzleless rocket (120 see).

Litchford, Ron J.

2001-01-01

50

Development of materials for open-cycle magnetohydrodynamics (MHD): ceramic electrode. Final report  

SciTech Connect

Pacific Northwest Laboratory, supported by the US Department of Energy, developed advanced materials for use in open-cycle, closed cycle magnetohydrodynamics (MHD) power generation, an advanced energy conversion system in which the flow of electrically conducting fluid interacts with an electric field to convert the energy directly into electricity. The purpose of the PNL work was to develop electrodes for the MHD channel. Such electrodes must have: (1) electrical conductivity above 0.01 (ohm-cm)/sup -1/ from near room temperature to 1900/sup 0/K, (2) resistance to both electrochemical and chemical corrosion by both slag and potassium seed, (3) resistance to erosion by high-velocity gases and particles, (4) resistance to thermal shock, (5) adequate thermal conductivity, (6) compatibility with other channel components, particularly the electrical insulators, (7) oxidation-reduction stability, and (8) adequate thermionic emission. This report describes the concept and development of high-temperature, graded ceramic composite electrode materials and their electrical and structural properties. 47 refs., 16 figs., 13 tabs.

Bates, J.L.; Marchant, D.D.

1986-09-01

51

Investigations for biogas operated MHD power generators  

SciTech Connect

Biogas is produced from the anaerobic fermentation of the organic matter containing cellulose, such as agricultural wastes, human wastes, animal wastes, etc. It contains methane (50-70%), carbon dioxide (30-50%), and very small amounts of hydrogen and hydrogen sulphide. Adequate quantities of raw material to generate biogas are normally available in rural areas, and therefore, there is a possibility that almost all the energy requirements of the rural sector may be fulfilled by biogas. Presently in the rural sector, biogas is used mainly to provide thermal energy (for cooking, etc.), and up to a limited extent, to meet the electrical energy requirements by running electrical generators with engines powered by a mixture of oil and biogas. In this paper, the authors propose a scheme in which biogas can be used to generate electricity more efficiently by using magnetohydrodynamic (MHD) power generators. Investigations have been carried out to make feasibility studies for biogas-operated open cycle MHD power generators. Composition, temperature and electrical conductivity of the seeded (with potassium) combustion products of biogas-air/oxygen systems have been analytically investigated for different percentages of CO/sub 2/ in biogas and at various combustor pressures for a seeding ratio of 1 percent by weight. The effect of preheating and enrichment of air on temperature and electrical conductivity of the seeded combustion plasmas has also been studied.

Dahiya, R.P.; Chand, A.; Sharma, S.C.

1983-12-01

52

Gas Core Reactor-MHD Power System with Cascading Power Cycle  

Microsoft Academic Search

The US Department of Energy initiative Gen-IV aim is to produce an entire nuclear energy production system with next generation features for certification before 2030. A Generation 4 capable system must have superior sustainability, safety and reliability, and economic cost advantages in comparison with third generation light water reactors. A gas core reactor (GCR) with magnetohydrodynamic (MHD) power converter and

Blair M. Smith; Samim Anghaie; Travis W. Knight

2002-01-01

53

FLIP MHD - A particle-in-cell method for magnetohydrodynamics  

NASA Technical Reports Server (NTRS)

The fluid-implicit-particle, or 'FLIP' method presently extended to 2D and 3D MHD flow incorporates a Lagrangian field representation and yields a grid magnetic Reynolds number of up to 16 while preserving contact continuities that retain the Galilean invariance of the MHD flow equations. Analytical arguments and numerical examples demonstrate the conservation of mass, momentum, magnetic flux, and energy; 2D calculation results for the illustrative cases of contact discontinuity convection, Rayleigh-Taylor unstable flow.

Brackbill, J. U.

1991-01-01

54

MHD generators in power production  

SciTech Connect

This paper reports on coalfired MHD steam combined-cycle power plants which offer significant improvements in overall plant efficiency as well as reduced environmental emissions. Development is currently in the proof-of-concept stage, with commercial plant retrofits under serious study.

Chapman, J.N.; Johanson, N.R. (Univ. of Tennessee, Space Inst., Tullahoma, TN (US))

1991-09-01

55

MHD generators in power production  

Microsoft Academic Search

This paper reports on coalfired MHD steam combined-cycle power plants which offer significant improvements in overall plant efficiency as well as reduced environmental emissions. Development is currently in the proof-of-concept stage, with commercial plant retrofits under serious study.

J. N. Chapman; N. R. Johanson

1991-01-01

56

Energy Conversion Alternatives Study (ECAS), Westinghouse phase 1. Volume 10: Liquid-metal MHD systems. [energy conversion efficiency of electric power plants using liquid metal magnetohydrodynamics  

NASA Technical Reports Server (NTRS)

Electric Power Plant costs and efficiencies are presented for two basic liquid-metal cycles corresponding to 922 and 1089 K (1200 and 1500 F) for a commercial applications using direct coal firing. Sixteen plant designs are considered for which major component equipment were sized and costed. The design basis for each major component is discussed. Also described is the overall systems computer model that was developed to analyze the thermodynamics of the various cycle configurations that were considered.

Holman, R. R.; Lippert, T. E.

1976-01-01

57

Gas Core Reactor with Magnetohydrodynamic Power System and Cascading Power Cycle  

Microsoft Academic Search

The U.S. Department of Energy initiative Generation IV aim is to produce an entire nuclear energy production system with next-generation features for certification before 2030. A Generation IV-capable system must have superior sustainability, safety and reliability, and economic cost advantages in comparison with third generation light water reactors (LWRs). A gas core reactor (GCR) with magnetohydrodynamic (MHD) power converter and

Blair M. Smith; Samim Anghaie

2004-01-01

58

Magnetohydrodynamic research program of the MHD Energy center at Mississippi State University and structural features of MHD radiant boilers  

NASA Astrophysics Data System (ADS)

Magnetohydrodynamic is conducted largerly through use of test stand which simulates conditions in the MHD gas stream. Continual modification of the test stand to reflect experimental results produced a test stand capable of test runs of 100 hours; runs of more than 500 hours are planned. The test stand is described, and experimental results are discussed. The design and construction of MHD radiant boiler are described. The radiant furnance serves several functions in a heat recovery and seed recovery system; it cools flue gases to a temperature suitable for entrance to the secondary superheater; it generates steam; it provides for the removal of molten ash at high temperatures; and it provides access for intrusive and nonintrusive instrumentation to the gas-side environment.

Shepard, W. S.

59

The Effect of Magnetohydrodynamic (MHD) Energy Bypass on Specific Thrust for a Supersonic Turbojet Engine  

NASA Technical Reports Server (NTRS)

This paper describes the preliminary results of a thermodynamic cycle analysis of a supersonic turbojet engine with a magnetohydrodynamic (MHD) energy bypass system that explores a wide range of MHD enthalpy extraction parameters. Through the analysis described here, it is shown that applying a magnetic field to a flow path in the Mach 2.0 to 3.5 range can increase the specific thrust of the turbojet engine up to as much as 420 N/(kg/s) provided that the magnitude of the magnetic field is in the range of 1 to 5 Tesla. The MHD energy bypass can also increase the operating Mach number range for a supersonic turbojet engine into the hypersonic flight regime. In this case, the Mach number range is shown to be extended to Mach 7.0.

Benyo, Theresa L.

2010-01-01

60

MHD (magnetohydrodynamic) undersea propulsion: A novel concept with renewed interest  

SciTech Connect

This paper discusses the reasons for the national and international renewed interest in the concept of MHD seawater propulsion. The main advantages of this concept are presented, together with some of the technical challenges that need to be overcome to achieve reliability, performance, and stealth. The paper discusses in more detail some of the technical issues and loss mechanisms influencing the thruster performance in terms of its electrical efficiency. Among the issues discussed are the jet losses and nozzle efficiency. Ohmic losses and frictional losses inside the thruster. Also discussed are the electrical end losses caused by the fringing magnetic field near the end of the electrodes. It has been shown that the frictional and end losses can have strong adverse effects on the thruster performance. Furthermore, a parametric study has been performed to investigate the effects of several parameters on the performance of the MHD thrusters. Those parameters include the magnetic field, thruster diameter, all roughness, flow velocity, and electrical load factor. The results of the parametric study indicate that the thruster efficiency increases with the strength of the magnetic field and thruster diameter, and decreases with the wall roughness and the flow velocity. 8 refs., 8 figs.

Doss, E.D.; Geyer, H.K. (Argonne National Lab., IL (USA)); Roy, G.D. (Office of Naval Research, Arlington, VA (USA))

1990-01-01

61

Theoretical MHD (magnetohydrodynamic) simulations of coronal transients and interplanetary observations  

SciTech Connect

A major long-range goal of theoretical simulations of solar-generated disturbances (transients, coronal holes, etc.) is the realistic modeling of a propagating disturbance from the sun into and throughout interplanetary space. Simulations of this kind, using MHD fluid theory, must always be confronted with observations in order to assess the degree to which one or the other is inadequate. We describe some of this on-going work which is concerned with both one- and two-dimensional, time-dependent MHD simulations. The first example simulates a flare-produced coronal transient. In this case, a sudden current pulse is assumed to produce emerging magnetic flux. This 'magnetic pulse' is sufficient to drive a weak shock wave into the solar wind by virtue of an outwardly-directed Lorentz force. The pulse is assumed to consist of a linearly-increasing (with time) magnetic field of 0.72 G at the base of a closed magnetic topology (initially in hydrostatic equilibrium) to a value ten times larger over a 10-minute period. The shock achieves a velocity of 230 km/s (which would be superimposed upon the existing solar wind). A second example deals with a series of corotating interaction regions observed during a 60-day period by Pioneers 10 and 11 in 1973 prior to, during, and subsequent to the former spacecraft's flyby of Jupiter. An opportunity for a stringent test of our one-dimensional model was made possible by the nearly radial alignment of these two spacecraft.

Dryer, M.; Steinolfson, R.S.; Smith, Z.K.

1982-12-27

62

Materials tests in support of an MHD (magnetohydrodynamic) coal combustor  

SciTech Connect

Corrosion tests were conducted to evaluate the compatibility of candidate alloys in simulated fireside and high-temperature, high- pressure waterside environments of slagging magnetohydrodynamic combustors. The fireside tests were conducted with uncoated specimens and specimens covered with deposit layers of slag or a mixture of slag and seed for as long as 750 h at 600 and 800{degree}F. The waterside corrosion tests were conducted at 450{degree}F in a high-pressure autoclave in which water with two different chemistries was used. Detailed results on the scaling kinetics are presented and the data are used to analyze the material options for different locations in the combustor system. 10 refs., 25 figs., 13 tabs.

Natesan, K.; Wang, D.Y.; Soppet, W.K.

1989-11-01

63

Two-dimensional magnetohydrodynamic simulations of poloidal flows in tokamaks and MHD pedestal  

SciTech Connect

Poloidal rotation is routinely observed in present-day tokamak experiments, in particular near the plasma edge and in the high-confinement mode of operation. According to the magnetohydrodynamic (MHD) equilibrium theory [R. Betti and J. P. Freidberg, Phys. Plasmas 7, 2439 (2000)], radial discontinuities form when the poloidal velocity exceeds the poloidal sound speed (or rather, more correctly, the poloidal magneto-slow speed). Two-dimensional compressible magnetohydrodynamic simulations show that the transonic discontinuities develop on a time scale of a plasma poloidal revolution to form an edge density pedestal and a localized velocity shear layer at the pedestal location. While such an MHD pedestal surrounds the entire core, the outboard side of the pedestal is driven by the transonic discontinuity while the inboard side is caused by a poloidal redistribution of the mass. The MHD simulations use a smooth momentum source to drive the poloidal flow. Soon after the flow exceeds the poloidal sound speed, the density pedestal and the velocity shear layer form and persist into a quasi steady state. These results may be relevant to the L-H transition, the early stages of the pedestal and edge transport barrier formation.

Guazzotto, L. [Department of Mechanical Engineering, University of Rochester, Rochester, New York 14627 (United States); Betti, R. [Department of Mechanical Engineering, University of Rochester, Rochester, New York 14627 (United States); Princeton Plasma Physics Laboratory, Princeton, New Jersey 08540 (United States)

2011-09-15

64

Dynamic modeling and control of magnetohydrodynamic\\/steam electrical power generating plants  

Microsoft Academic Search

A dynamic power-flow simulation of an overall magnetohydrodynamic (MHD)\\/steam electrical power generating plant is developed. Several control configurations are applied to the system, and their effects on system dynamic response are presented. The overall combined-cycle system model utilizes an input-output characterization of the combustor\\/nozzle\\/channel\\/diffuser. This characterization is developed from polynomial approximations of data resulting from the solutions of energy balance,

J. D. Aspnes; D. A. Pierre

1977-01-01

65

MHD pulsed power generation and applications  

Microsoft Academic Search

We have been proposing to use non-equilibrium MHD generator as a pulsed power supply for various applications. This system has inherent advantages of high power density, high reliability and high durability compared with combustion driven type equilibrium MHD generator. For this system, Non-equilibrium Plasma Generator (NPG), where light metal combustion with pure oxygen heat up working medium of inert gas,

N. Harada

2001-01-01

66

MHD-EMP interaction with power transmission and distribution systems  

SciTech Connect

A nuclear detonation at altitudes of several hundred kilometers above the earth will distort the earth's magnetic field and results in a time-variation of the geomagnetic field on the earth's surface. This magnetic field interacts with the finitely conducting earth to produce a time varying electric field, also on the earth's surface. Known at the magnetohydrodynamic electromagnetic pulse (MHD-EMP), this resulting E-field can induce a net voltage in long electrical conductors, such as power transmission lines. If these conductors are electrically connected to the earth at both ends, a current can be induced to flow in the conductors, and this can cause damage or upset to certain electrical systems. This paper presents the results of a study on the interaction of the MHD-EMP with power transmission and distribution (T D) systems. A brief overview of the MHD-EMP environment used in the study is presented, and the analytical models used for estimating the coupling of this environment to T D lines are discussed. Because of the quasi-static nature of MHD-EMP, the models are essentially simple DC circuit models. However, complications arise in attempting to treat realistic line configurations having a large number of support towers and an overhead shield or neutral wires. There models are discussed in detail. 3 refs., 5 figs., 1 tab.

Tesche, F.M. (Tesche (F.M.), Dallas, TX (United States)); Barnes, P.R. (Oak Ridge National Lab., TN (United States))

1991-01-01

67

MHD-EMP interaction with power transmission and distribution systems  

SciTech Connect

A nuclear detonation at altitudes of several hundred kilometers above the earth will distort the earth`s magnetic field and results in a time-variation of the geomagnetic field on the earth`s surface. This magnetic field interacts with the finitely conducting earth to produce a time varying electric field, also on the earth`s surface. Known at the magnetohydrodynamic electromagnetic pulse (MHD-EMP), this resulting E-field can induce a net voltage in long electrical conductors, such as power transmission lines. If these conductors are electrically connected to the earth at both ends, a current can be induced to flow in the conductors, and this can cause damage or upset to certain electrical systems. This paper presents the results of a study on the interaction of the MHD-EMP with power transmission and distribution (T&D) systems. A brief overview of the MHD-EMP environment used in the study is presented, and the analytical models used for estimating the coupling of this environment to T&D lines are discussed. Because of the quasi-static nature of MHD-EMP, the models are essentially simple DC circuit models. However, complications arise in attempting to treat realistic line configurations having a large number of support towers and an overhead shield or neutral wires. There models are discussed in detail. 3 refs., 5 figs., 1 tab.

Tesche, F.M. [Tesche (F.M.), Dallas, TX (United States); Barnes, P.R. [Oak Ridge National Lab., TN (United States)

1991-12-01

68

Rapporteur report: MHD electric power plants  

NASA Technical Reports Server (NTRS)

Five US papers from the Proceedings of the Seventh International Conference on MHD Electrical Power Generation at the Massachusetts Institute of Technology are summarized. Results of the initial parametric phase of the US effort on the study of potential early commercial MHD plants are reported and aspects of the smaller commercial prototype plant termed the Engineering Test Facility are discussed. The alternative of using a disk geometry generator rather than a linear generator in baseload MHD plants is examined. Closed-cycle as well as open-cycle MHD plants are considered.

Seikel, G. R.

1980-01-01

69

Priority pollutants in solid phase combustion products from the Department of Energy's MHD (magnetohydrodynamics) Coal-Fired Flow Facility  

Microsoft Academic Search

One area not addressed in the past assessments of a coal-fired, open-cycle Magnetohydrodynamics (MHD) system is the presence, location, and behavior of EPA-listed priority pollutants. Consequently, an effort was started to identify and quantify the minute constituents leaving an MHD system. At the University of Tennessee Space Institute (UTSI), representative samples were obtained from the major components of the Department

1990-01-01

70

Simulation of high-frequency solar wind power spectra using Hall magnetohydrodynamics  

Microsoft Academic Search

Solar wind frequency spectra show a distinct steepening of the f-5\\/3 power law inertial range spectrum at frequencies above the Doppler-shifted ion cyclotron frequency. This is commonly attributed to dissipation due to wave-particle interactions. We consider the extent to which this steepening can be described, using a magnetohydrodynamic formulation that includes the Hall term. An important characteristic of Hall MHD

S. Ghosh; E. Siregar; D. A. Roberts; M. L. Goldstein

1996-01-01

71

Meshless Local Petrov–Galerkin (MLPG) method for the unsteady magnetohydrodynamic (MHD) flow through pipe with arbitrary wall conductivity  

Microsoft Academic Search

In this article a meshless local Petrov–Galerkin (MLPG) method is given to obtain the numerical solution of the coupled equations in velocity and magnetic field for unsteady magnetohydrodynamic (MHD) flow through a pipe of rectangular section having arbitrary conducting walls. Computations have been carried out for different Hartmann numbers and wall conductivity at various time levels. The method is based

Mehdi Dehghan; Davoud Mirzaei

2009-01-01

72

Solar driven liquid metal MHD power generator  

SciTech Connect

A method for solar electric power generation in space is described. A solar energy collector focuses solar energy onto a solar oven which is attached to a mixer which in turn is attached to the channel of a MHD generator. Gas enters the oven and a liquid metal enters the mixer. The gas/liquid metal mixture is heated by the collected solar energy and moves through the MHD generator thereby generating electrical power. The mixture is then separated and recycled. NASA

Lee, J.H.; Hohl, F.

1981-05-01

73

Gas Core Reactor-MHD Power System with Cascading Power Cycle  

SciTech Connect

The US Department of Energy initiative Gen-IV aim is to produce an entire nuclear energy production system with next generation features for certification before 2030. A Generation 4 capable system must have superior sustainability, safety and reliability, and economic cost advantages in comparison with third generation light water reactors. A gas core reactor (GCR) with magnetohydrodynamic (MHD) power converter and cascading power cycle forms the basis for a Generation IV concept that is expected to set the upper performance limits in sustainability and power conversion efficiency among all existing and proposed fission powered systems. A gaseous core reactor delivering 1000's MW fission power acts as the heat source for a high temperature magnetohydrodynamic power converter. A uranium tetrafluoride fuel mix, with {approx}95% mole fraction helium gas, provides a stable working fluid for the primary MHD-Brayton cycle. A helium Brayton cycle extracts waste heat from the MHD generator with about 20% energy efficiency, but the low temperature side is still hot enough ({approx}1600 K) to drive a second conventional helium Brayton cycle with about 35% efficiency. There is enough heat at the low temperature side of the He-Brayton cycle to generate steam, and so another heat recovery cycle can be added, this time a Rankine steam cycle with up to 40% efficiency. The proof of concept does not require a tremendously efficient (first law) MHD cycle, the high temperature direct energy conversion capability of an MHD dynamo, combined with already sophisticated steam powered turbine industry knowledge base allows the cascading cycle design to achieve break-through first law energy efficiencies previously unheard of in the nuclear power industry. Although simple in concept, the gas core reactor design has not achieved the state of technological maturity that, say, molten salt or high-temperature gas-cooled reactors have pioneered. However, even on paper the GCR-MHD concept holds considerable promise, for example, like molten salt reactors the fuel is continuously cycled, allowing high-burnup, and continuous burning of actinides, and hence greatly improved fuel utilization. The fuel inventory is two orders of magnitude lower than LWR's of comparable power output and fissile plutonium production is likewise lower than in spent LWR fuel. Besides these features this paper discusses specific GCR-MHD design challenges such as fission enhanced gas conductivity in the MHD channel, GCR safety issues and related engineering problems. (authors)

Smith, Blair M.; Anghaie, Samim; Knight, Travis W. [Innovative Nuclear Space Power and Propulsion Institute, University of Florida, PO Box 116502, Gainesville, FL, 32611 (United States)

2002-07-01

74

Solar driven liquid metal MHD power generator  

NASA Technical Reports Server (NTRS)

A solar energy collector focuses solar energy onto a solar oven which is attached to a mixer which in turn is attached to the channel of a MHD generator. Gas enters the oven and a liquid metal enters the mixer. The gas/liquid metal mixture is heated by the collected solar energy and moves through the MHD generator thereby generating electrical power. The mixture is then separated and recycled.

Lee, J. H.; Hohl, F. (inventors)

1983-01-01

75

Solar driven liquid metal mhd power generator  

SciTech Connect

A solar energy collector focuses solar energy onto a solar oven which is attached to a mixer which in turn is attached to the channel of a mhd generator. Gas enters the oven and a liquid metal enters the mixer. The gas/liquid metal mixture is heated by the collected solar energy and moves through the mhd generator thereby generating electrical power. The mixture is then separated and recycled.

Hohl, F.; Lee, J.H.

1983-06-14

76

Solar driven liquid metal MHD power generator  

NASA Astrophysics Data System (ADS)

A solar energy collector focuses solar energy onto a solar oven which is attached to a mixer which in turn is attached to the channel of a MHD generator. Gas enters the oven and a liquid metal enters the mixer. The gas/liquid metal mixture is heated by the collected solar energy and moves through the MHD generator thereby generating electrical power. The mixture is then separated and recycled.

Lee, J. H.; Hohl, F.

1983-06-01

77

Lattice Boltzmann simulation of thermofluidic transport phenomena in a DC magnetohydrodynamic (MHD) micropump.  

PubMed

A comprehensive non-isothermal Lattice Boltzmann (LB) algorithm is proposed in this article to simulate the thermofluidic transport phenomena encountered in a direct-current (DC) magnetohydrodynamic (MHD) micropump. Inside the pump, an electrically conducting fluid is transported through the microchannel by the action of an electromagnetic Lorentz force evolved out as a consequence of the interaction between applied electric and magnetic fields. The fluid flow and thermal characteristics of the MHD micropump depend on several factors such as the channel geometry, electromagnetic field strength and electrical property of the conducting fluid. An involved analysis is carried out following the LB technique to understand the significant influences of the aforementioned controlling parameters on the overall transport phenomena. In the LB framework, the hydrodynamics is simulated by a distribution function, which obeys a single scalar kinetic equation associated with an externally imposed electromagnetic force field. The thermal history is monitored by a separate temperature distribution function through another scalar kinetic equation incorporating the Joule heating effect. Agreement with analytical, experimental and other available numerical results is found to be quantitative. PMID:21053082

Chatterjee, Dipankar; Amiroudine, Sakir

2011-02-01

78

Off-design study of an open-cycle MHD power plant with oxygen enrichment  

SciTech Connect

This paper explores some of the more important aspects of off-design operation for an magnetohydrodynamic (MHD) power plant. An essential requirement is that the plant be designed to meet part-load and overload conditions. Furthermore, the optimal design should be subject to a specified load demand curve. For off-design regimes, an analysis is made to determine the compatible joint operating conditions for an MHD topping cycle, a steam bottoming plant, a turbine train, a compressor, and an oxygen separation plant. The analysis performed is subject to constraints (e.g. metal temperatures, second law violations, component performance requirements, environmental considerations). 12 refs.

Geyer, H.K.; Berry, G.F.

1981-01-01

79

Alterations in human ECG due to the MagnetoHydroDynamic effect: A method for accurate R peak detection in the presence of high MHD artifacts  

Microsoft Academic Search

Blood flow in high static magnetic fields induces elevated voltages that contaminate the ECG signal which is recorded simultaneously during MRI scans for synchronization purposes. This is known as the magnetohydrodynamic (MHD) effect, it increases the amplitude of the T wave, thus hindering correct R peak detection. In this paper, we inspect the MHD induced alterations of human ECG signals

Dima Abi-Abdallah; Vincent Robin; Agnès Drochon; Odette Fokapu

2007-01-01

80

Ideal MHD Stability Prediction and Required Power for EAST Advanced Scenario  

NASA Astrophysics Data System (ADS)

The Experimental Advanced Superconducting Tokamak (EAST) is the first fully superconducting tokamak with a D-shaped cross-sectional plasma presently in operation. The ideal magnetohydrodynamic (MHD) stability and required power for the EAST advanced tokamak (AT) scenario with negative central shear and double transport barrier (DTB) are investigated. With the equilibrium code TOQ and stability code GATO, the ideal MHD stability is analyzed. It is shown that a moderate ratio of edge transport barriers' (ETB) height to internal transport barriers' (ITBs) height is beneficial to ideal MHD stability. The normalized beta ?N limit is about 2.20 (without wall) and 3.70 (with ideal wall). With the scaling law of energy confinement time, the required heating power for EAST AT scenario is calculated. The total heating power Pt increases as the toroidal magnetic field BT or the normalized beta ?N is increased.

Chen, Junjie; Li, Guoqiang; Qian, Jinping; Liu, Zixi

2012-11-01

81

Solar driven liquid metal MHD power generator  

Microsoft Academic Search

A method for solar electric power generation in space is described. A solar energy collector focuses solar energy onto a solar oven which is attached to a mixer which in turn is attached to the channel of a MHD generator. Gas enters the oven and a liquid metal enters the mixer. The gas\\/liquid metal mixture is heated by the collected

J. H. Lee; F. Hohl

1981-01-01

82

Oxygen blown coal gasifier supplying MHD-steam power plant  

Microsoft Academic Search

A magnetohydrodynamic generator (30) is fired with a clean, medium btu combustible gas produced in an oxygen atmosphere. The combustible gas is generated in an oxygen blown coal gasifier (10) and cleaned of sulfur compounds, nitrogen compounds, and particulate matter before being delivered to the burner (32) of the MHD generator (30). An air separation plant (70) is provided to

Bozzuto

1982-01-01

83

Transmission of DC-Voltage Energy from Magnetohydrodynamic Generators into an Electric Power Network.  

National Technical Information Service (NTIS)

The article discusses the possibilities of changing electrical DC-energy obtained in MHD (magnetohydrodynamic) generators with Hall, Montardy and Faraday connection systems into tri-phase AC energy. It presents diagrams of inverters built from thyristors ...

Z. Badzinski A. Kordus

1969-01-01

84

Flow simulation of the Component Development Integration Facility magnetohydrodynamic power train system  

SciTech Connect

This report covers application of Argonne National Laboratory`s (ANL`s) computer codes to simulation and analysis of components of the magnetohydrodynamic (MHD) power train system at the Component Development and Integration Facility (CDIF). Major components of the system include a 50-MWt coal-fired, two-stage combustor and an MHD channel. The combustor, designed and built by TRW, includes a deswirl section between the first and the second-stage combustor and a converging nozzle following the second-stage combustor, which connects to the MHD channel. ANL used computer codes to simulate and analyze flow characteristics in various components of the MHD system. The first-stage swirl combustor was deemed a mature technology and, therefore, was not included in the computer simulation. Several versions of the ICOMFLO computer code were used for the deswirl section and second-stage combustor. The MGMHD code, upgraded with a slag current leakage submodel, was used for the MHD channel. Whenever possible data from the test facilities were used to aid in calibrating parameters in the computer code, to validate the computer code, or to set base-case operating conditions for computations with the computer code. Extensive sensitivity and parametric studies were done on cold-flow mixing in the second-stage combustor, reacting flow in the second-stage combustor and converging nozzle, and particle-laden flow in the deswirl zone of the first-stage combustor, the second-stage combustor, and the converging nozzle. These simulations with subsequent analysis were able to show clearly in flow patterns and various computable measures of performance a number of sensitive and problematical areas in the design of the power train. The simulations of upstream components also provided inlet parameter profiles for simulation of the MHD power generating channel. 86 figs., 18 tabs.

Chang, S.L.; Lottes, S.A.; Bouillard, J.X.; Petrick, M.

1997-11-01

85

Non-Equilibrium Plasma MHD Electrical Power Generation at Tokyo Tech  

NASA Astrophysics Data System (ADS)

This paper reviews the recent activities on radio-frequency (rf) electromagnetic-field-assisted magnetohydrodynamic (MHD) power generation experiments at the Tokyo Institute of Technology. An inductively coupled rf field (13.56 MHz) is continuously supplied to the disk-shaped Hall-type MHD generator. The first part of this paper describes a method of obtaining increased power output from a pure Argon plasma MHD power generator by incorporating an rf power source to preionize and heat the plasma. The rf heating enhances ionization of the Argon and raises the temperature of the free electron population above the nominally low 4500 K temperatures obtained without rf heating. This in turn enhances the plasma conductivity making MHD power generation feasible. We demonstrate an enhanced power output when rf heating is on approximately 5 times larger than the input power of the rf generator. The second part of this paper is a demonstration of a physical phenomenon of the rf-stabilization of the ionization instability, that had been conjectured for some time, but had not been seen experimentally. The rf heating suppresses the ionization instability in the plasma behavior and homogenizes the nonuniformity of the plasma structures. The power-generating performance is significantly improved with the aid of the rf power under wide seeding conditions. The increment of the enthalpy extraction ratio of around 2% is significantly greater than the fraction of the net rf power, that is, 0.16%, to the thermal input.

Murakami, T.; Okuno, Y.; Yamasaki, H.

2008-02-01

86

High-power density MHD experiments  

NASA Astrophysics Data System (ADS)

Some results of an ongoing proof-of-concept study of combustion MHD as a viable power source for use with space-based weapons systems are reviewed. An aluminum/carbon solid fuel has been successfully burned in a hybrid combustor and reignition demonstrated. The discussion covers the design of this combustor system and experimental results from the initial hybrid combustor and generator tests.

Schmidt, H. J.; Lineberry, J. T.; Chapman, J. N.

1990-01-01

87

Closed cycle MHD power plant and retrofit optimization application  

NASA Astrophysics Data System (ADS)

The results of two independent studies of closed-cycle MHD power systems are presented. A combined cycle consisting of an MHD closed-cycle topping unit retrofitted to an existing steam bottoming plant is considered. Preliminary results of an ongoing parametric study of an MHD closed-cycle system utilizing an integrated pressurized coal gasifier are discussed.

Cutting, J. C.; Owens, W. R.; Sheth, P. R.; Griswold, J.; Wehrey, M.

1980-06-01

88

Closed cycle MHD power plant and retrofit optimization application  

Microsoft Academic Search

The results of two independent studies of closed-cycle MHD power systems are presented. A combined cycle consisting of an MHD closed-cycle topping unit retrofitted to an existing steam bottoming plant is considered. Preliminary results of an ongoing parametric study of an MHD closed-cycle system utilizing an integrated pressurized coal gasifier are discussed.

W. R. Owens; P. R. Sheth; J. Griswold; M. Wehrey

1980-01-01

89

Regulation Properties of a System MHD Generator - Electric Power Network.  

National Technical Information Service (NTIS)

In this report several problems connected with the mutual operation of MHD generator and electric power network are described, i.e. regulation properties of the MHD-generator, optimal matching of the MHD-generator and converters, current regulation in tra...

Krzysztof D

1987-01-01

90

System study of an MHD\\/gas turbine combined-cycle baseload power plant  

Microsoft Academic Search

The magnetohydrodynamics (MHD) gas turbine systems were modeled with sufficient detail, using realistic component specifications and costs, so that that the thermal and economic performance of the systems could be accurately determined. Three cases of MHD gas turbine systems were studied, with Case I being similar to a MHD steam system so that a direct comparison of the performances could

K. D. Annen

1981-01-01

91

MHD Retrofit of Steam Power Plants. Feasibility Study. Summary and Conclusions, Part I.  

National Technical Information Service (NTIS)

The US Department of Energy Division of Magnetohydrodynamics (DOE/MHD) initiated this study to evaluate the feasibility of a retrofit option to reduce the time and cost of commercializing MHD. The MHD retrofit option will integrate a nominal 260 megawatt ...

1979-01-01

92

MHD generator onboard space vehicle  

NASA Astrophysics Data System (ADS)

The idea of extracting electric energy using a magnetohydrodynamic (MHD) generator arranged onboard space capsule is considered. For the conditions at one point on the trajectory of Stardust (NASA space probe) mission, it is numerically demonstrated that an electric power of about 3 MW can be gained by the proposed MHD generator, which amounts to abut 5% of the total enthalpy flux.

Bityurin, V. A.; Bocharov, A. N.

2011-04-01

93

CDIF combustor design. [For coal-fired MHD generator  

Microsoft Academic Search

Magnetohydrodynamic (MHD) electric power development offers a major opportunity for better utilization of U. S. coal supplies. Conceptual studies of MHD power systems project coal pile to bus bar plant efficiencies up to 50 percent better than modern steam cycles and 20 to 30 percent better than advanced combined gas turbine-steam turbine cycles. MHD offers further potential advantages in control

D. B. Stickler; R. T. Barnes

1976-01-01

94

Micro optical fiber display switch based on the magnetohydrodynamic (MHD) principle  

NASA Astrophysics Data System (ADS)

This paper reports on a research effort to design, microfabricate and test an optical fiber display switch based on magneto hydrodynamic (MHD) principal. The switch is driven by the Lorentz force and can be used to turn on/off the light. The SU-8 photoresist and UV light source were used for prototype fabrication in order to lower the cost. With a magnetic field supplied by an external permanent magnet, and a plus electrical current supplied across the two inert sidewall electrodes, the distributed body force generated will produce a pressure difference on the fluid mercury in the switch chamber. By change the direction of current flow, the mercury can turn on or cut off the light pass in less than 10 ms. The major advantages of a MHD-based micro-switch are that it does not contain any solid moving parts and power consumption is much smaller comparing to the relay type switches. This switch can be manufactured by molding gin batch production and may have potential applications in extremely bright traffic control,, high intensity advertising display, and communication.

Lian, Kun; Heng, Khee-Hang

2001-09-01

95

Magnetohydrodynamic projects at the CDIF  

NASA Astrophysics Data System (ADS)

The Component Development and Integration Facility (CDIF) is a major US Department of Energy magnetohydrodynamic (MHD) test facility in Butte, Montana. The CDIF is operated by MSE, Inc. Within the national MHD program, MSE personnel are responsible for performing integration testing of vendor-supplied MHD power train components at the CDIF to support the goal of commercialization. During the first quarter of FY92, MHD testing was initiated. Off-line and on-line calibration tests were completed for the Endress+Hauser flowmeter, and thermal, conductivity, and electrical testing was initiated.

96

Effective method for MHD retrofit of power plants  

SciTech Connect

Retrofitting existing power plants with an open-cycle MHD system has been re-examined in light of recent developments in the heat and seed recovery technology area. A new retrofit cycle configuration has been developed which provides for a direct gas-gas coupling; also, the MHD topping cycle can be decoupled from the existing plant for either separate or joint operation. As an example, the MHD retrofit concept has been applied to Illinois Power Company's Vermilion Station No. 1, a coal-fired power plant presently in operation. Substantial increases in efficiency have been demonstrated and the economic validity of the MHD retrofit approach has been established.

Berry, G.F.; Dennis, C.B.; Johnson, T.R.; Minkov, V.

1981-10-01

97

Oxygen blown coal gasifier supplying MHD-steam power plant  

SciTech Connect

A magnetohydrodynamic generator (30) is fired with a clean, medium btu combustible gas produced in an oxygen atmosphere. The combustible gas is generated in an oxygen blown coal gasifier (10) and cleaned of sulfur compounds, nitrogen compounds, and particulate matter before being delivered to the burner (32) of the MHD generator (30). An air separation plant (70) is provided to supply oxygen to both the MHD burner (32) and the coal gasifier (10). Nitrogen from the air separation plant (70) is preheated and utilized to dry the coal supplied to the gasifier (10). A vapor generator (40) is disposed downstream of the MHD generator (30) to receive and cool the hot gases exiting therefrom thereby generating steam.

Bozzuto, C.R.

1982-08-24

98

MHD/steam combined cycle power plant: A technology update.  

National Technical Information Service (NTIS)

The MHD/steam combined cycle power plant concept involves burning fossil fuel at high temperatures ((approximately)5000 F), generating power with an MHD generator from the high temperature exhaust products and using a steam plant for conversion of the rem...

N. R. Johanson R. C. Attig J. N. Chapman

1990-01-01

99

Dynamic simulation of MHD topping cycles  

Microsoft Academic Search

Combined Cycle MHD (magnetohydrodynamics)\\/steam power plants show promise of achieving high efficiency in coal energy conversion to electricity. The plants are composed of an MHD topping cycle operating in the combustion gas temperature range of 3000-2000 K and a bottoming cycle consisting of a modified steam power plant in the steam temperature range of 810 - 300 K. This paper

R. Johnson; D. Bartle

1980-01-01

100

Disk Geometry MHD Generator for High Voltage High Power Aircraft Requirements.  

National Technical Information Service (NTIS)

The disk represents a magnetohydrodynamic (MHD) channel geometry in which either a simple outward radial flow occurs, or there is a combination of radial flow with swirl. Distinguishing features and major advantages of the disk are electrodeless walls, an...

J. E. Klepeis, J. F. Louis

1974-01-01

101

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

102

Influence of Diffuser Performance on Commercial MHD/Steam Power Plants. Final Report.  

National Technical Information Service (NTIS)

The Department of Energy, Division of Magnetohydrodynamics (DOE/MHD), requested Gilbert/Commonwealth to investigate the effects of diffuser pressure recovery coefficient, design characteristics and heat loss (to the feedwater for cooling the diffuser) on ...

1979-01-01

103

A study of a commercial MHD power plant scheme  

Microsoft Academic Search

Power engineering specialists are currently interested in electrical power stations with magnetohydrodynamic generators. This\\u000a interest has been generated by the fact that fossil fuels are becoming increasingly costlier, and with the exploitation of\\u000a remote and practically inaccessible deposits, a more rational utilisation of fuel has become necessary.\\u000a \\u000a Research on magnetohydrodynamic generators is being conducted in many countries at present. In

S. A. Pashkov; E. V. Shishkov

1980-01-01

104

Integrated MHD (Magnetohydrodynamics) Bottoming Cycle: Second Quarterly Report, November 1, 1987-January 31, 1988.  

National Technical Information Service (NTIS)

The Integrated MHD Bottoming Cycle project, progress for September and October relates to Task 1--Modification of the Existing Coal Pulverizer and Dryer System, and Task 2--Design, Fabrication, and Installation of an Automated Spent Seed/Ash Handling Syst...

1988-01-01

105

Integrated MHD (Magnetohydrodynamics) Bottoming Cycle: Third Quarterly Report, February 1-April 30, 1988.  

National Technical Information Service (NTIS)

The Integrated MHD Bottoming Cycle project progress for February through April relates to Task 1--Modification of the Existing Coal Pulverizer and Dryer System, and Task 2--Design, Fabrication, and Installation of an Automated Spent Seed/Ash Handling Syst...

1988-01-01

106

Experimental investigation of flow characteristics of a magnetohydrodynamic (MHD) duct of fan-shaped cross section  

Microsoft Academic Search

Experiments along with numerical calculations are carried out to investigate the effect of the geometry of the cross section\\u000a on flow characteristics of a MHD propulsion duct. A fan-shaped cross-section MHD thruster duct is chosen for comparison with\\u000a a previously investigated rectangular cross section. Measurement of the velocity field is made using LDV (Laser Doppler Velocimetry)\\u000a system with a fiber-optic

Seong Jae Kim; Choung Mook Lee; Sang Joon Lee

1997-01-01

107

An investigation into the feasibility of a radiant recuperative air heater for a magnetohydrodynamic/steam power plant  

SciTech Connect

The ultimate high efficiencies envisioned for a magnetohydrodynamic (MHD)/steam power plant have been based on the development of a regenerative high temperature air heater (HTAH). Oxygen enriched and vitiation heated air has been used in current test facilities and is proposed for early commercial plants to circumvent the costly development of the HTAH for MHD. Since the US DOE Coal Fired Flow Facility (CFFF) routinely conducts proof-of-concept (POC) MHD tests lasting several hundred hours, it was decided that it would be simple and inexpensive to include materials tests to investigate their suitability for either a recuperative or regenerative type high temperature air heater for MHD applications. Although both the regenerator and recuperator required for use in the MHD environment are beyond the state-of-the-art, the recuperator is much less complex operationally and should be less expensive. This interim report identifies a material and recuperator concept that warrants further testing and development based on the test results presented herein. An additional material was also identified which was highly resistant to corrosion and thus may have value as a protective coating. This phase of the study was concerned with the screening of candidate materials on a pass/fail basis, thus, little effort was made toward collecting accurate temperature data for each sample. The next phase will concentrate on acquiring more engineering data on the materials. Measurements will also be made to determine the effectiveness of the recuperator concept. 24 refs., 79 figs., 9 tabs.

Boss, W.H.; Babu, S.

1991-01-01

108

Magnetohydrodynamic (MHD) analyses of various forms of activity and their propagation through helio spheric space  

NASA Technical Reports Server (NTRS)

Theoretical and numerical modeling of solar activity and its effects on the solar atmosphere within the context of magnetohydrodynamics were examined. Specifically, the scientific objectives were concerned with the physical mechanisms for the flare energy build-up and subsequent release. In addition, transport of this energy to the corona and solar wind was also investigated. Well-posed, physically self-consistent, numerical simulation models that are based upon magnetohydrodynamics were sought. A systematic investigation of the basic processes that determine the macroscopic dynamic behavior of solar and heliospheric phenomena was conducted. A total of twenty-three articles were accepted and published in major journals. The major achievements are summarized.

Wu, S. T.

1987-01-01

109

Simulation of two-dimensional fully developed laminar flow for a magneto-hydrodynamic (MHD) pump.  

PubMed

MHD micro-pumps circumvent the wear and fatigue caused by high pressure-drop across the check valves of mechanical micro-pumps in micro-fluidic systems. Early analyses of the fluid flow for MHD micro-pumps were mostly made possible by the Poiseuille flow theory; however, this conventional laminar approach cannot illustrate the effects of various channel sizes and shapes. This paper, therefore, presents a simplified MHD flow model based upon steady state, incompressible and fully developed laminar flow theory to investigate the characteristics of a MHD pump. Inside the pump, flowing along the channel is the electrically conducting fluid flowing driven by the Lorentz forces in the direction perpendicular to both dc magnetic field and applied electric currents. The Lorentz forces were converted into a hydrostatic pressure gradient in the momentum equations of the MHD channel flow model. The numerical simulations conducted with the explicit finite difference method show that the channel dimensions and the induced Lorentz forces have significant influences on the flow velocity profile. Furthermore, the simulation results agree well with the experimental results published by other researchers. PMID:15142583

Wang, Pei-Jen; Chang, Chia-Yuan; Chang, Ming-Lang

2004-07-30

110

Solar driven liquid metal MHD power generator  

Microsoft Academic Search

A solar energy collector focuses solar energy onto a solar oven which is attached to a mixer which in turn is attached to the channel of a MHD generator. Gas enters the oven and a liquid metal enters the mixer. The gas\\/liquid metal mixture is heated by the collected solar energy and moves through the MHD generator thereby generating electrical

J. H. Lee; F. Hohl

1983-01-01

111

Experiments in Magnetohydrodynamics  

ERIC Educational Resources Information Center

Describes three student experiments in magnetohydrodynamics (MHD). In these experiments, it was found that the electrical conductivity of the local water supply was sufficient to demonstrate effectively some of the features of MHD flowmeters, generators, and pumps. (LC)

Rayner, J. P.

1970-01-01

112

MHD Power Generation Research, Development and Engineering. Quarterly Progress Report, October-December 1979.  

National Technical Information Service (NTIS)

Progress is reported on the following tasks: characterization of coal for open-cycle MHD power generation systems; compressive creep and strength studies of MHD preheater materials; preparation of coals for utilization in direct coal-fired MHD generation;...

1979-01-01

113

Open-cycle magnetohydrodynamic power plant based upon direct-contact closed-loop high-temperature heat exchanger  

DOEpatents

A magnetohydrodynamic (MHD) power generating system is described in which ionized combustion gases with slag and seed are discharged from an MHD combustor and pressurized high temperature inlet air is introduced into the combustor for supporting fuel combustion at high temperatures necessary to ionize the combustion gases, and including a heat exchanger in the form of a continuous loop with a circulating heat transfer liquid such as copper oxide. The heat exchanger has an upper horizontal channel for providing direct contact between the heat transfer liquid and the combustion gases to cool the gases and condense the slag which thereupon floats on the heat transfer liquid and can be removed from the channel, and a lower horizontal channel for providing direct contact between the heat transfer liquid and pressurized air for preheating the inlet air. The system further includes a seed separator downstream of the heat exchanger.

Berry, G.F.; Minkov, V.; Petrick, M.

1981-11-02

114

Open-cycle magnetohydrodynamic power plant based upon direct-contact closed-loop high-temperature heat exchanger  

DOEpatents

A magnetohydrodynamic (MHD) power generating system in which ionized combustion gases with slag and seed are discharged from an MHD combustor and pressurized high temperature inlet air is introduced into the combustor for supporting fuel combustion at high temperatures necessary to ionize the combustion gases, and including a heat exchanger in the form of a continuous loop with a circulating heat transfer liquid such as copper oxide. The heat exchanger has an upper horizontal channel for providing direct contact between the heat transfer liquid and the combustion gases to cool the gases and condense the slag which thereupon floats on the heat transfer liquid and can be removed from the channel, and a lower horizontal channel for providing direct contact between the heat transfer liquid and pressurized air for preheating the inlet air. The system further includes a seed separator downstream of the heat exchanger.

Berry, Gregory F. (Naperville, IL); Minkov, Vladimir (Skokie, IL); Petrick, Michael (Joliet, IL)

1988-01-01

115

Development and application of a nonequilibrium magnetohydrodynamics code to hypersonic flow power generation  

NASA Astrophysics Data System (ADS)

The time-dependent, 2½-dimensional, axisymmetric, magnetohydrodynamics (MHD) solver MACH2 has been upgraded to include the effects of non-equilibrium air chemistry using the well-established reaction model developed by Park. Several validation cases are presented based on comparisons to the experimentally deduced shock stand-off distance of nitrogen flow over spheres, the shock stand-off distance of spheres fired into air in a ballistic test facility, and the electron number density on the surface of the Ram-C re-entry experiment. In addition, the magnetic induction equation has been upgraded with new verified models that compute the effects of the Hall and ion slip terms. The upgraded code is utilized to model an annular, Hall-type MHD generator that can be employed upstream of a turbojet engine for freestream conditions corresponding to Mach 5 flight at an altitude of 20km. The simulations demonstrate the feasibility of convening inlet kinetic power to storable electric power. Using ionization provided by electron-beam guns and a radial magnetic field B=3T, the generator is shown to produce a maximum of 4.8MW of electric power while reducing the total kinetic power of the flow by 31%. Optimizing the loading parameter, K*Load, across the electrodes demonstrates that the generator could produce 1.54MW of excess electric power that can be stored and used for on-board power requirements. Further, the reduction in flow kinetic power results in an increase in static pressure of 30% and a reduction in stagnation temperature of 3% at the turbojet's compressor inlet that aids the subsequent process of combustion.

Lorzel, Heath

116

Integrated MHD (Magnetohydrodynamics) Bottoming Cycle: Fourth Quarterly Report, May 1-July 31, 1988.  

National Technical Information Service (NTIS)

The Integrated MHD Bottoming Cycle project progress for May through July relates to Task 1--Modification of the Existing Coal Pulverizer and Dryer System, and Task 2--Design, Fabrication, and Installation of an Automated Spent Seed/Ash Handling System and...

1988-01-01

117

MHD (magnetohydrodynamic) flow tailoring in first wall coolant channels of self-cooled blankets  

SciTech Connect

MHD flow tailoring, the use of salient features of MHD flows in strong magnetic fields to create desirable velocity profiles in single ducts, presents the possibility of significant reduction in blanket complexity and cost, and enhancement of thermal hydraulic performance. A particular form of flow tailoring, involving ducts with alternating expansions and contractions lends itself to the design of first wall coolant ducts. The potential benefits of this configuration and its immediate applicability to blanket design have made it the choice as the first joint Argonne National Laboratory (ANL)/Kernforschungszentrum Karlsruhe (KfK) test on liquid metal MHD. Testing is being carried out at ANL's ALEX facility on a test article fabricated at KfK. A description of the test article, its important features, and the associated instrumentation are presented. A fully 3-D code capable of treating MHD flows in ducts of complex geometry has been developed and used in the flow tailoring experiements. The features and capabilities of the code are discussed and a sample of the code predictions for the geometry and conditions of the experiments are presented. A sample of the preliminary test results from the ongoing testing is also given. 9 refs., 9 figs.

Picologlou, B.F.; Reed, C.R.; Hua, T.Q.; Barleon, L.; Kreuzinger, H.; Walker, J.S.

1988-02-01

118

Economic Evaluation of MHD-Steam Powerplants Employing Coal Gasification.  

National Technical Information Service (NTIS)

To assess the efficacy and economics of producing power from coal, four open-cycle magnetohydrodynamic (MHD) processing schemes were selected for study. Each involved a different mode of coal combustion and level of gas cleanliness. The options considered...

D. Bienstock J. J. Demeter K. D. Plants P. D. Bergman

1973-01-01

119

Numerical Modelling and Experimental Study of an AC Magnetohydrodynamic (MHD) Micropump  

Microsoft Academic Search

This paper describes the working principle and provides FEM simulations and some experimental results of an AC magneto-hydrodynamic micropump. The pump, without moving parts, operates at low-frequency, medium-high AC magnetic fields without gas bubble formation and produces a continuous flow. Therefore, it is in principle compatible with biological samples in a miniaturized total analysis system (muTAS). A preliminary prototype was

Antonio Affanni; Giovanni Chiorboli

2006-01-01

120

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

121

Rare-earth hafnium oxide materials for magnetohydrodynamic (MHD) generator application  

Microsoft Academic Search

Several ceramic materials based on rare-earth hafnium oxides have been identified as potential high-temperature electrodes and low-temperature current leadouts for open cycle coal-fired MHD generator channels. The electrode-current leadouts combination must operate at temperatures between 400 and 2000K with an electrical conductivity greater than 10⁻² ohm⁻¹ cm⁻¹. The electrodes will be exposed to flowing (linear flow rates up to 100

D. D Marchant; J. L. Bates

1979-01-01

122

Design study of superconducting magnets for a combustion magnetohydrodynamic (MHD) generator  

NASA Technical Reports Server (NTRS)

Design trade off studies for 13 different superconducting magnet systems were carried out. Based on these results, preliminary design characteristics were prepared for several superconducting magnet systems suitable for use with a combustion driven MHD generator. Each magnet generates a field level of 8 T in a volume 1.524 m (60 in.) long with a cross section 0.254 m x 0.254 m (10 in. x 10 in.) at the inlet and 0.406 m x .406 m (16 in. x 16 in.) at the outlet. The first design involves a racetrack coil geometry intended for operation at 4.2 K; the second design uses a racetrack geometry at 2.0 K; and the third design utilizes a rectangular saddle geometry at 4.2 K. Each case was oriented differently in terms of MHD channel axis and main field direction relative to gravity in order to evaluate fabrication ease. All cases were designed such that the system could be disassembled to allow for alteration of field gradient in the MHD channel by changing the angle between coils. Preliminary design characteristics and assembly drawings were generated for each case.

Thome, R. J.; Ayers, J. W.

1977-01-01

123

MHD generator scaling analysis for baseload commercial power plants  

SciTech Connect

MHD generator channel scaling analyses have been performed to definitize the effect of generator size and oxygen enrichment on channel performance. These studies have shown that MHD generator channels can be designed to operate efficiently over the range of 250 to 2135 thermal megawatts. The optimum design conditions for each of the thermal inputs were established by investigating various combinations of electrical load parameters, pressure ratios, magnetic field profiles, and channel lengths. These results provide design flexibility for the baseload combined cycle MHD/steam power plant.

Swallom, D.W.; Pian, C.C.P.

1982-01-01

124

Multi-MW Closed Cycle MHD Nuclear Space Power Via Nonequilibrium He/Xe Working Plasma  

NASA Technical Reports Server (NTRS)

Prospects for a low specific mass multi-megawatt nuclear space power plant were examined assuming closed cycle coupling of a high-temperature fission reactor with magnetohydrodynamic (MHD) energy conversion and utilization of a nonequilibrium helium/xenon frozen inert plasma (FIP). Critical evaluation of performance attributes and specific mass characteristics was based on a comprehensive systems analysis assuming a reactor operating temperature of 1800 K for a range of subsystem mass properties. Total plant efficiency was expected to be 55.2% including plasma pre-ionization power, and the effects of compressor stage number, regenerator efficiency and radiation cooler temperature on plant efficiency were assessed. Optimal specific mass characteristics were found to be dependent on overall power plant scale with 3 kg/kWe being potentially achievable at a net electrical power output of 1-MWe. This figure drops to less than 2 kg/kWe when power output exceeds 3 MWe. Key technical issues include identification of effective methods for non-equilibrium pre-ionization and achievement of frozen inert plasma conditions within the MHD generator channel. A three-phase research and development strategy is proposed encompassing Phase-I Proof of Principle Experiments, a Phase-II Subscale Power Generation Experiment, and a Phase-III Closed-Loop Prototypical Laboratory Demonstration Test.

Litchford, Ron J.; Harada, Nobuhiro

2011-01-01

125

MHD power systems for reduction of CO 2 emission  

Microsoft Academic Search

To reduce the emission of CO2 into the atmosphere, two schemes are proposed. The first one is a coal-fired MHD-steam combined power generation system where coal is burned with oxygen rather than air, the obtained high temperature is utilized for the MHD generator and the CO2 is liquefied and recovered. The cycle efficiency with CO2 recovery is estimated to be

M. Ishikawa; Meyer Steinberg

1998-01-01

126

Evaluation of the ECAS open cycle MHD power plant design  

NASA Technical Reports Server (NTRS)

The Energy Conversion Alternatives Study (ECAS) MHD/steam power plant is described. The NASA critical evaluation of the design is summarized. Performance of the MHD plant is compared to that of the other type ECAS plant designs on the basis of efficiency and the 30-year levelized cost of electricity. Techniques to improve the plant design and the potential performance of lower technology plants requiring shorter development time and lower development cost are then discussed.

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

1978-01-01

127

Estimation of Specific Mass for Multimegawatt NEP Systems Based on Vapor Core Reactors with MHD Power Conversion  

NASA Astrophysics Data System (ADS)

Very low specific-mass power generation in space is possible using Vapor Core Reactors with Magnetohydrodynamic (VCR/MHD) generator. These advanced reactors at the conceptual design level have potential for the generation of tens to hundreds of megawatts of power in space with specific mass of about 1 kg/kWe. Power for nuclear electric propulsion (NEP) is possible with almost direct power conditioning and coupling of the VCR/MHD power output to the VASIMR engine, MPD, and a whole host of electric thrusters. The VCR/MHD based NEP system is designed to power space transportation systems that dramatically reduce the mission time for human exploration of the entire solar system or for aggressive long-term robotic missions. There are more than 40 years of experience in the evaluation of the scientific and technical feasibility of gas and vapor core reactor concepts. The proposed VCR is based on the concept of a cavity reactor made critical through the use of a reflector such as beryllium or beryllium oxide. Vapor fueled cavity reactors that are considered for NEP applications operate at maximum core center and wall temperatures of 4000 K and 1500K, respectively. A recent investigation has resulted in the conceptual design of a uranium tetrafluoride fueled vapor core reactor coupled to a MHD generator. Detailed neutronic design and cycle analyses have been performed to establish the operating design parameters for 10 to 200 MWe NEP systems. An integral system engineering-simulation code is developed to perform parametric analysis and design optimization studies for the VCR/MHD power system. Total system weight and size calculated based on existing technology has proven the feasibility of achieving exceptionally low specific mass (? ~1 kg/kWe) with a VCR/MHD powered system.

Knight, Travis; Anghaie, Samim

2004-02-01

128

FORCED FIELD EXTRAPOLATION: TESTING A MAGNETOHYDRODYNAMIC (MHD) RELAXATION METHOD WITH A FLUX-ROPE EMERGENCE MODEL  

SciTech Connect

We undertake an attempt to reconstruct the Sun's non-force-free magnetic field. The solar corona is often considered to be magnetohydrostatic. We solve the full MHD equations with a semi-realistic atmosphere model to attain this stationary state. Our method is tested with a Sun-like model which simulates the emergence of a magnetic flux rope passing from below the photosphere into the corona. Detailed diagnostics shows that our method can model the forced field more successfully than the optimization and potential method, but it still needs to be applied to real data.

Zhu, X. S.; Wang, H. N.; Du, Z. L.; Fan, Y. L., E-mail: xszhu@bao.ac.cn [Key Laboratory of Solar Activity, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China)

2013-05-10

129

Three-dimensional MHD (magnetohydrodynamic) flows in rectangular ducts of liquid-metal-cooled blankets  

SciTech Connect

Magnetohydrodynamic flows of liquid metals in rectangular ducts with thin conducting walls in the presence of strong nonuniform transverse magnetic fields are examined. The interaction parameter and Hartmann number are assumed to be large, whereas the magnetic Reynolds number is assumed to be small. Under these assumptions, viscous and inertial effects are confined in very thin boundary layers adjacent to the walls. A significant fraction of the fluid flow is concentrated in the boundary layers adjacent to the side walls which are parallel to the magnetic field. This paper describes the analysis and numerical methods for obtaining 3-D solutions for flow parameters outside these layers, without solving explicitly for the layers themselves. Numerical solutions are presented for cases which are relevant to the flows of liquid metals in fusion reactor blankets. Experimental results obtained from the ALEX experiments at Argonne National Laboratory are used to validate the numerical code. In general, the agreement is excellent. 5 refs., 14 figs.

Hua, T.Q.; Walker, J.S.; Picologlou, B.F.; Reed, C.B.

1988-07-01

130

Experiments on H2-O2mhd Power Generation.  

National Technical Information Service (NTIS)

Magnetohydrodynamic power generation experiments utilizing a cesium-seeded H2-O2 working fluid were carried out using a diverging area Hall duct having an entrance Mach number of 2. The experiments were conducted in a high-field strength cryomagnet facili...

J. M. Smith

1980-01-01

131

MAGNETOHYDRODYNAMIC WAVES AND CORONAL HEATING: UNIFYING EMPIRICAL AND MHD TURBULENCE MODELS  

SciTech Connect

We present a new global model of the solar corona, including the low corona, the transition region, and the top of the chromosphere. The realistic three-dimensional magnetic field is simulated using the data from the photospheric magnetic field measurements. The distinctive feature of the new model is incorporating MHD Alfven wave turbulence. We assume this turbulence and its nonlinear dissipation to be the only momentum and energy source for heating the coronal plasma and driving the solar wind. The difference between the turbulence dissipation efficiency in coronal holes and that in closed field regions is because the nonlinear cascade rate degrades in strongly anisotropic (imbalanced) turbulence in coronal holes (no inward propagating wave), thus resulting in colder coronal holes, from which the fast solar wind originates. The detailed presentation of the theoretical model is illustrated with the synthetic images for multi-wavelength EUV emission compared with the observations from SDO AIA and STEREO EUVI instruments for the Carrington rotation 2107.

Sokolov, Igor V.; Van der Holst, Bart; Oran, Rona; Jin, Meng; Manchester, Ward B. IV; Gombosi, Tamas I. [Department of AOSS, University of Michigan, 2455 Hayward Street, Ann Arbor, MI 48109 (United States)] [Department of AOSS, University of Michigan, 2455 Hayward Street, Ann Arbor, MI 48109 (United States); Downs, Cooper [Predictive Science Inc., 9990 Mesa Rim Road, Suite 170, San Diego, CA 92121 (United States)] [Predictive Science Inc., 9990 Mesa Rim Road, Suite 170, San Diego, CA 92121 (United States); Roussev, Ilia I. [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States)] [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); Evans, Rebekah M., E-mail: igorsok@umich.edu [NASA Goddard Space Flight Center, Space Weather Lab, 8800 Greenbelt Road, Greenbelt, MD 20771 (United States)

2013-02-10

132

Recovering Photospheric Velocities from Vector Magnetograms by using a Three-Dimensional, Fully Magnetohydrodynamic (MHD) Model  

NASA Technical Reports Server (NTRS)

We introduce a numerical simulation method for recovering the photospheric velocity field from the vector magnetograms. The traditional method is local correlation tracking (LCT) which is based on measuring the relative displacements of features in blocks of pixels between successive white-light images or magnetograms. Within this method, there are a variety of implementations. One of recently developed implementations is induction local correlation tracking (ILCT) as described by Welsch et al. (2004). They employ the normal component of magnetic induction equation as a constraint to assure consistent solutions. Our numerical method uses the fully three-dimensional MHD equations to recover the photospheric velocity field with individual vector magnetograms. We compare our method to the ILCT method using NOAA AR8210 as an example. The differences and similarities are discussed in detail.

Wang, A. H.; Wu, S. T.; Liu, Yang; Hathaway, D.

2008-01-01

133

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

134

Advanced fusion MHD power conversion using the CFAR cycle concept  

SciTech Connect

The CFAR (compact fusion advanced Rankine) concept for a tokamak reactor involves the use of a high-temperature Rankine cycle in combination with microwave superheaters and nonequilibrium MHD disk generators to obtain a compact, low-capital-cost power conversion system which fits almost entirely within the reactor vault. The significant savings in the balance-of-plant costs are expected to result in much lower costs of electricity than previous concepts. This paper describes the unique features of the CFAR cycle and a high-temperature blanket designed to take advantage of it as well as the predicted performance of the MHD disk generators using mercury seeded with cesium.

Hoffman, M.A.; Campbell, R.; Logan, B.G.

1989-03-01

135

H2-O2 combustion powered steam-MHD central power systems  

NASA Technical Reports Server (NTRS)

Estimates are made for both the performance and the power costs of H2-O2 combustion powered steam-MHD central power systems. Hydrogen gas is assumed to be transmitted by pipe from a remote coal gasifier into the city and converted to electricity in a steam MHD plant having an integral gaseous oxygen plant. These steam MHD systems appear to offer an attractive alternative to both in-city clean fueled conventional steam power plants and to remote coal fired power plants with underground electric transmission into the city.

Seikel, G. R.; Smith, J. M.; Nichols, L. D.

1974-01-01

136

Impinging jet separators for liquid metal magnetohydrodynamic power cycles  

NASA Technical Reports Server (NTRS)

In many liquid metal MHD power, cycles, it is necessary to separate the phases of a high-speed liquid-gas flow. The usual method is to impinge the jet at a glancing angle against a solid surface. These surface separators achieve good separation of the two phases at a cost of a large velocity loss due to friction at the separator surface. This report deals with attempts to greatly reduce the friction loss by impinging two jets against each other. In the crude impinging jet separators tested to date, friction losses were greatly reduced, but the separation of the two phases was found to be much poorer than that achievable with surface separators. Analyses are presented which show many lines of attack (mainly changes in separator geometry) which should yield much better separation for impinging jet separators).

Bogdanoff, D. W.

1973-01-01

137

MHD: direct channel from heat to electricity  

SciTech Connect

Magnetohydrodynamics (MHD) combined with conventional power generation is promising, but several engineering and technological problems must be solved before it can compete in the electric utility market. A combined MHD topping cycle and steam-electric bottoming cycle would raise the efficiency of a coal-fired plant from 35 to as high as 50 percent. Coal requirements would be lowered and internal sulfur oxide control is possible. Some of the components for MHD generation can be adapted from industrial applications and are already available, but many new components must be designed. Schematic drawings illustrate the engineering complexities of an MHD plant. (DCK)

Lihach, N.; Zygielbaum, P.; Lowenstein, A.

1980-04-01

138

The MHD\\/steam combined cycle power plant; A technology update  

Microsoft Academic Search

The MHD\\/steam combined cycle power plant concept involves burning fossil fuel at high temperatures (â¼5000 F), generating power with an MHD generator from the high temperature exhaust products and using a steam plant for conversion of the remaining thermal energy to electricity. The MHD portion is called the topping cycle and the steam plant is called the bottoming cycle. Conversion

N. R. Johanson; R. C. Attig; J. N. Champman

1990-01-01

139

The MHD\\/steam combined cycle power plant: A technology update  

Microsoft Academic Search

The MHD\\/steam combined cycle power plant concept involves burning fossil fuel at high temperatures (â¼5000 F), generating power with an MHD generator from the high temperature exhaust products and using a steam plant for conversion of the remaining thermal energy to electricity. The MHD portion is called the topping cycle and the steam plant is called the bottoming cycle. The

N. R. Johanson; R. C. Attig; J. N. Chapman

1990-01-01

140

Technical support for open-cycle MHD program  

Microsoft Academic Search

The support program for open-cycle MHD (magnetohydrodynamic) at Argonne National Lab is developing the analytical tools needed to investigate the performance of the major components in the combined-cycle MHD\\/steam power system. The analytical effort is centered on the primary components of the system that are unique to MHD and also on the integration of these analytical representations into a model

J. Patten

1978-01-01

141

Performance calculations for 1000 MWe MHD/steam power plants  

NASA Technical Reports Server (NTRS)

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

Pian, C. C. P.

1981-01-01

142

Performance calculations for 1000 MWe MHD/steam power plants  

SciTech Connect

The effects of MHD generator operating conditions and constraints on the performance of MHD/steam power plants are investigated. Power plants using high-temperature combustion air preheat (2500/sup 0/F) and plants using intermediate-temperature preheat (1100/sup 0/F) with oxygen enenrichment are considered. Variations of these two types of power plants are compared on the basis of fixed total electrical output (1000 MW/sub e/). Results are presented to show the effects of generator length and level of oxygen enrichment on the plant thermodynamic efficiency and on the required generator mass flow rate. Factors affecting the optimum levels of oxygen enrichment are analyzed. It is shown that oxygen enrichment can reduce the magnet stored energy requirement.

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

1981-01-01

143

System study of an MHD/gas turbine combined-cycle baseload power plant  

NASA Astrophysics Data System (ADS)

The magnetohydrodynamics (MHD) gas turbine systems were modeled with sufficient detail, using realistic component specifications and costs, so that that the thermal and economic performance of the systems could be accurately determined. Three cases of MHD gas turbine systems were studied, with Case I being similar to a MHD steam system so that a direct comparison of the performances could be made, with Case II being representative of a second generation MHD system, and with Case III considering oxygen enrichment for early commercial applications. The results show that the MHD gas turbine system has very good thermal and economic performances while requiring either little or no cooling water. Compared to the MHD steam system which has a cooling tower heat load of 720 MN, the Base Case I MHD/gas turbine system has a heat rate which is 13% higher and a cost of electricity which is only 7% higher while requiring no cooling water. Case II results show that an improved performance can be expected from second generation MHD gas turbine systems. Case III results show that an oxygen enriched MHD gas turbine system may be attractive for early commercial applications in dry regions of the country.

Annen, K. D.

1981-08-01

144

Experimental Performance of Two Segmented Wall Magnetohydrodynamic Electric Power Generators.  

National Technical Information Service (NTIS)

A test program was conducted for the University of Tennessee Space Institute on a vertically segmented wall (Hall) and a diagonally segmented wall (45-deg) magnetohydrodynamic generator. The generators were 48 in. in length and had inside dimensions of 2 ...

R. J. LeBoeuf M. A. Nelius

1967-01-01

145

MHD Advanced Power Train Phase I, Final Report, Volume 6  

SciTech Connect

Under contract to the Department of Energy, Westinghouse has prepared the definition of a program plan for the development of an MHD Advanced Power Train (APT). The scope of work of this contract includes conceptual designs of early commercial MHD/steam electric plants (topping/bottoming) ranging from 200 to 1000 Mw(e). These plant designs were prepared during 1982 and made use of a system analysis model that provides performance and design information and economic estimates. In early April 1984, DOE requested westinghouse to perform special studies under the existing APT contract to aid the Department in evaluating MHD program options. Two tasks were defined by DOE: the first task was to evaluate an 80 MW(t) integrated test system (with steam electric bottoming cycle) for installation at the CDIF in Butte, Montana; the second task was to investigate placing a 50 MW(e) MHD topping stage onto an existing steam electric plant (as a retrofit). This volume of the final report documents the results of these special studies. Highlights of the studies were presented orally to DOE on May 15, 1984.

A. R. Jones

1985-08-01

146

Magnetohydrodynamic energy conversion by using convexly divergent channel  

NASA Astrophysics Data System (ADS)

We describe a magnetohydrodynamic (MHD) electrical power generator equipped with a convexly divergent channel, as determined through shock-tunnel-based experiments. The quality of MHD power-generating plasma and the energy conversion efficiency in the convexly divergent channel are compared with those from previous linearly divergent channel. The divergence enhancement in the channel upstream is effective for suppressing an excessive increase in static pressure, whereby notably high isentropic efficiency is achieved.

Murakami, Tomoyuki; Okuno, Yoshihiro

2009-12-01

147

MHD Advanced Power Train Phase I, Final Report, Volume 7  

SciTech Connect

This appendix provides additional data in support of the MHD/Steam Power Plant Analyses reported in report Volume 5. The data is in the form of 3PA/SUMARY computer code printouts. The order of presentation in all four cases is as follows: (1) Overall Performance; (2) Component/Subsystem Information; (3) Plant Cost Accounts Summary; and (4) Plant Costing Details and Cost of Electricity.

A. R. Jones

1985-08-01

148

Towards Integrated Pulse Detonation Propulsion and MHD Power  

NASA Technical Reports Server (NTRS)

The interest in pulse detonation engines (PDE) arises primarily from the advantages that accrue from the significant combustion pressure rise that is developed in the detonation process. Conventional rocket engines, for example, must obtain all of their compression from the turbopumps, while the PDE provides additional compression in the combustor. Thus PDE's are expected to achieve higher I(sub sp) than conventional rocket engines and to require smaller turbopumps. The increase in I(sub sp) and the decrease in turbopump capacity must be traded off against each other. Additional advantages include the ability to vary thrust level by adjusting the firing rate rather than throttling the flow through injector elements. The common conclusion derived from these aggregated performance attributes is that PDEs should result in engines which are smaller, lower in cost, and lighter in weight than conventional engines. Unfortunately, the analysis of PDEs is highly complex due to their unsteady operation and non-ideal processes. Although the feasibility of the basic PDE concept has been proven in several experimental and theoretical efforts, the implied performance improvements have yet to be convincingly demonstrated. Also, there are certain developmental issues affecting the practical application of pulse detonation propulsion systems which are yet to be fully resolved. Practical detonation combustion engines, for example, require a repetitive cycle of charge induction, mixing, initiation/propagation of the detonation wave, and expulsion/scavenging of the combustion product gases. Clearly, the performance and power density of such a device depends upon the maximum rate at which this cycle can be successfully implemented. In addition, the electrical energy required for direct detonation initiation can be significant, and a means for direct electrical power production is needed to achieve self-sustained engine operation. This work addresses the technological issues associated with PDEs for integrated aerospace propulsion and MHD power. An effort is made to estimate the energy requirements for direct detonation initiation of potential fuel/oxidizer mixtures and to determine the electrical power requirements. This requirement is evaluated in terms of the possibility for MHD power generation using the combustion detonation wave. Small scale laboratory experiments were conducted using stoichiometric mixtures of acetylene and oxygen with an atomized spray of cesium hydroxide dissolved in alcohol as an ionization seed in the active MHD region. Time resolved thrust and MHD power generation measurements were performed. These results show that PDEs yield higher I(sub sp) levels than a comparable rocket engine and that MHD power generation is viable candidate for achieving self-excited engine operation.

Litchford, Ron J.; Thompson, Bryan R.; Lineberry, John T.

1999-01-01

149

Gyroscopic analog for magnetohydrodynamics  

SciTech Connect

The gross features of plasma equilibrium and dynamics in the ideal magnetohydrodynamics (MHD) model can be understood in terms of a dynamical system which closely resembles the equations for a deformable gyroscope.

Holm, D.D.

1981-01-01

150

Magnetohydrodynamic Underwater Acoustic Transducer.  

National Technical Information Service (NTIS)

The magnetohydrodynamic (MHD) and thermoacoustic sound generation mechanisms were investigated analytically and experimentally for a source volume region generated by a time harmonic electric current distribution interacting in a static magnetic field usi...

S. C. Shreppler

1986-01-01

151

Plasma plume MHD power generator and method  

DOEpatents

A method is described of generating power at a situs exposed to the solar wind which comprises creating at separate sources at the situs discrete plasma plumes extending in opposed directions, providing electrical communication between the plumes at their source and interposing a desired electrical load in the said electrical communication between the plumes.

Hammer, J.H.

1993-08-10

152

Experiments on H2-O2MHD power generation  

NASA Technical Reports Server (NTRS)

Magnetohydrodynamic power generation experiments utilizing a cesium-seeded H2-O2 working fluid were carried out using a diverging area Hall duct having an entrance Mach number of 2. The experiments were conducted in a high-field strength cryomagnet facility at field strengths up to 5 tesla. The effects of power takeoff location, axial duct location within the magnetic field, generator loading, B-field strength, and electrode breakdown voltage were investigated. For the operating conditions of these experiments, it is found that the power output increases with the square of the B-field and can be limited by choking of the channel or interelectrode voltage breakdown which occurs at Hall fields greater than 50 volts/insulator. Peak power densities of greater than 100 MW/cu M were achieved.

Smith, J. M.

1980-01-01

153

Comparative analysis of CCMHD power plants. [Closed Cycle MHD  

NASA Technical Reports Server (NTRS)

A study of Closed Cycle MHD (CCMHD) power generation systems has been conducted which emphasizes both advances in component conceptual design and overall system performance. New design data are presented for the high temperature, regenerative argon heaters (HTRH) and the heat recovery/seed recovery (HRSR) subsystem. Contamination of the argon by flue gas adsorbed in the HTRH is examined and a model for estimation of contamination effects in operating systems is developed. System performance and cost data have been developed for the standard CCMHD/steam cycle as powered by both direct fired cyclone combustors and selected coal gasifiers. In addition, a new CCMHD thermodynamic cycle has been identified.

Alyea, F. N.; Marston, C. H.; Mantri, V. B.; Geisendorfer, B. G.; Doss, H.

1981-01-01

154

MHD/steam electrical power production - Promise, progress and problems  

NASA Astrophysics Data System (ADS)

The MHD/Steam Power Plant has promise to burn coal and produce electrical power more efficiently than conventional coal fired plants while producing less environmental intrusion. Problems have been encountered in developing a high temperature air heater (HTAH) using coal exhaust products. Early commercial plants have been proposed that use either a gasifier to produce clean fuel for a separately fired HTAH or use oxygen enrichment to avoid the need for a HTAH. Component development is progressing rapidly but test data is needed at intermediate sizes before a commercial plant can be designed with high confidence of success. Related commercial technology is being adapted for the steam bottoming plant.

Chapman, J. N.; Strom, S. S.; Wu, Y. C. L.

1980-08-01

155

System studies of coal fired-closed cycle MHD for central station power plants  

NASA Technical Reports Server (NTRS)

This paper presents a discussion of the closed-cycle MHD results obtained in a recent study of various advanced energy-conversion power systems. The direct coal-fired MHD topping-steam bottoming cycle was established as the current choice for central station power generation. Emphasis is placed on the background assumptions and the conclusions that can be drawn from the closed-cycle MHD analysis. It is concluded that closed-cycle MHD has efficiencies comparable to that of open-cycle MHD. Its cost will possibly be slightly higher than that of the open-cycle MHD system. Also, with reasonable fuel escalation assumptions, both systems can produce lower-cost electricity than conventional steam power plants. Suggestions for further work in closed-cycle MHD components and systems are made.

Zauderer, B.

1976-01-01

156

Dynamic modeling and control of magnetohydrodynamic\\/steam systems  

Microsoft Academic Search

Dynamic characteristics of magnetohydrodynamic (MHD)\\/steam electrical power generating plants are investigated, as are control requirements for desirable system response. A dynamic computer model of the MHD\\/steam combined cycle is developed. Representative computer simulation results showing the effects of various control configurations are given, including a quasi-optimized response based on minimizing integral-square error of actual system output compared with desired output.

J. Aspnes; D. A. Pierre

1977-01-01

157

Simultaneous Effects of MHD and Thermal Radiation on the Mixed Convection Stagnation-Point Flow of a Power-Law Fluid  

NASA Astrophysics Data System (ADS)

Magnetohydrodynamic (MHD) mixed convection stagnation-point flow and heat transfer of power-law fluids towards a stretching surface is investigated. The homotopy analysis method (HAM) is used in finding the series solution for a nonlinear problem. Closed form solutions for velocity and temperature fields are presented in the limiting cases. Graphical results are shown. It is found that velocity and temperature are decreasing functions of power law index. Numerical computations for shear stress coefficient and local Nusselt number are reported. The present results are also compared with the existing numerical solution in a limiting sense.

Hayat, T.; Mustafa, M.; Obaidat, S.

2011-07-01

158

Analysis of the Magneto-Hydrodynamic (MHD) Energy Bypass Engine for High-Speed Air-Breathing Propulsion  

NASA Technical Reports Server (NTRS)

The performance of the MHD energy bypass air-breathing engine for high-speed propulsion is analyzed in this investigation. This engine is a specific type of the general class of inverse cycle engines. In this paper, the general relationship between engine performance (specific impulse and specific thrust) and the overall total pressure ratio through an engine (from inlet plane to exit plane) is first developed and illustrated. Engines with large total pressure decreases, regardless of cause or source, are seen to have exponentially decreasing performance. The ideal inverse cycle engine (of which the MHD engine is a sub-set) is then demonstrated to have a significant total pressure decrease across the engine; this total pressure decrease is cycle-driven, degrades rapidly with energy bypass ratio, and is independent of any irreversibility. The ideal MHD engine (inverse cycle engine with no irreversibility other than that inherent in the MHD work interaction processes) is next examined and is seen to have an additional large total pressure decrease due to MHD-generated irreversibility in the decelerator and the accelerator. This irreversibility mainly occurs in the deceleration process. Both inherent total pressure losses (inverse cycle and MHD irreversibility) result in a significant narrowing of the performance capability of the MHD bypass engine. The fundamental characteristics of MHD flow acceleration and flow deceleration from the standpoint of irreversibility and second-law constraints are next examined in order to clarify issues regarding flow losses and parameter selection in the MM modules. Severe constraints are seen to exist in the decelerator in terms of allowable deceleration Mach numbers and volumetric (length) required for meaningful energy bypass (work interaction). Considerable difficulties are also encountered and discussed due to thermal/work choking phenomena associated with the deceleration process. Lastly, full engine simulations utilizing inlet shock systems, finite-rate chemistry, wall cooling with thermally balanced engine (fuel heat sink), fuel injection and mixing, friction, etc. are shown and discussed for both the MHD engine and the conventional scramjet. The MHD bypass engine has significantly lower performance in all categories across the Mach number range (8 to 12.2). The lower performance is attributed to the combined effects of 1) additional irreversibility and cooling requirements associated with the MHD components and 2) the total pressure decrease associated with the inverse cycle itself.

Riggins, David W.

2002-01-01

159

Conceptual design analysis of an MHD power conversion system for droplet-vapor core reactors. Final report  

SciTech Connect

A nuclear driven magnetohydrodynamic (MHD) generator system is proposed for the space nuclear applications of few hundreds of megawatts. The MHD generator is coupled to a vapor-droplet core reactor that delivers partially ionized fissioning plasma at temperatures in range of 3,000 to 4,000 K. A detailed MHD model is developed to analyze the basic electrodynamics phenomena and to perform the design analysis of the nuclear driven MHD generator. An incompressible quasi one dimensional model is also developed to perform parametric analyses.

Anghaie, S.; Saraph, G.

1995-12-31

160

Engineering support for magnetohydrodynamic power plant analysis and design studies  

NASA Technical Reports Server (NTRS)

The major factors which influence the economic engineering selection of stack inlet temperatures in combined cycle MHD powerplants are identified and the range of suitable stack inlet temperatures under typical operating conditions is indicated. Engineering data and cost estimates are provided for four separately fired high temperature air heater (HTAH) system designs for HTAH system thermal capacity levels of 100, 250, 500 and 1000 MWt. An engineering survey of coal drying and pulverizing equipment for MHD powerplant application is presented as well as capital and operating cost estimates for varying degrees of coal pulverization.

Carlson, A. W.; Chait, I. L.; Marchmont, G.; Rogali, R.; Shikar, D.

1980-01-01

161

Computer controlled MHD power consolidation and pulse generation system  

SciTech Connect

The major goal of this research project is to establish the feasibility of a power conversion technology which will permit the direct synthesis of computer programmable pulse power. Feasibility will be established in this project by demonstration of direct synthesis of commercial frequency power by means of computer control. The power input to the conversion system is assumed to be a MHD Faraday connected generator which may be viewed as a multi-terminal dc source. This consolidation/inversion process is referred to subsequently as Pulse-Amplitude-Synthesis-and-Control (PASC). A secondary goal is to deliver a controller subsystem consisting of a computer, software, and computer interface board which can serve as one of the building blocks for a possible Phase 2 prototype system.

Johnson, R.; Marcotte, K.; Donnelly, M.

1990-05-29

162

MHD contractors' review meeting. Abstracts.  

National Technical Information Service (NTIS)

The following research programs on magnetohydrodynamic conversion were described at the contractors' review meeting: MHD integrated topping cycle project; Activity summary for DOE's component development and integration facility; MHD bottoming cycle compo...

1991-01-01

163

Experiments on H2-O2 MHD power generation  

NASA Technical Reports Server (NTRS)

MHD power generation experiments utilizing a cesium-seeded H2-O2 working fluid have been carried out using a diverging area Hall duct having an entrance Mach number of 2. The experiments are conducted in a high-field strength cryomagnet facility at field strengths up to 5 tesla. The effects of power takeoff location, axial duct location within the magnetic field, generator loading, B-field strength, and electrode breakdown voltage were investigated. For the operating conditions of these experiments it is found that the power output increases with the square of the B-field and can be limited by choking of the channel or interelectrode voltage breakdown which occurs at Hall fields greater than 50 volts/insulator.

Smith, J. M.

1980-01-01

164

MHD-steam thermal power plant electrical stations with zero stack emission  

Microsoft Academic Search

A system study of a combined cycle MHD-steam thermal power plant electrical station with zero stack emission through recirculation of CO 2, is presented. The design of the MHD generator of the topper is done by means of a quasi-one dimensional optimization model. The technology of the components is conventional. An overall efficiency larger than 40% for power plants with

C. A. Borghi; P. L. Ribani

1996-01-01

165

Stability of open-cycle MHD generation system connected to power transmission line  

Microsoft Academic Search

The stability of the binary combined system of an MHD generator and a synchronous generator, including inverter and power transmission system, is studied numerically. The binary combined power generation system is a pilot plant scale with thermal input of about 110MW and consists of a MHD generator as a topping cycle and a steam turbine generator as a bottoming cycle.

Nobuhiko Hayanose; Yoshitaka Inui; Motoo Ishikawa; Juro Umoto

1998-01-01

166

Results from conceptual design study of potential early commercial MHD/steam power plants  

SciTech Connect

This paper presents information developed in two phases of a joint study of Potential Early Commercial MHD Power Plants. The main objective of this study is to develop information on such plants in order to identify attractive entry level plant designs requiring less development than more mature MHD power plants defined by previous studies. 6 refs.

Hals, F.; Kessler, R.; Westra, L.; Zar, J.; Morgan, W.; Bozzuto, C.

1981-01-01

167

Numerical simulations of strong incompressible magnetohydrodynamic turbulence  

SciTech Connect

Magnetised plasma turbulence pervades the universe and is likely to play an important role in a variety of astrophysical settings. Magnetohydrodynamics (MHD) provides the simplest theoretical framework in which phenomenological models for the turbulent dynamics can be built. Numerical simulations of MHD turbulence are widely used to guide and test the theoretical predictions; however, simulating MHD turbulence and accurately measuring its scaling properties is far from straightforward. Computational power limits the calculations to moderate Reynolds numbers and often simplifying assumptions are made in order that a wider range of scales can be accessed. After describing the theoretical predictions and the numerical approaches that are often employed in studying strong incompressible MHD turbulence, we present the findings of a series of high-resolution direct numerical simulations. We discuss the effects that insufficiencies in the computational approach can have on the solution and its physical interpretation.

Mason, J.; Cattaneo, F. [Department of Astronomy and Astrophysics, University of Chicago, 5640 South Ellis Avenue, Chicago, Illinois 60637 (United States); Perez, J. C. [Space Science Center and Department of Physics, University of New Hampshire, Durham, New Hampshire 03824 (United States); Boldyrev, S. [Department of Physics, University of Wisconsin at Madison, 1150 University Ave, Madison, Wisconsin 53706 (United States)

2012-05-15

168

Application of polyalgorithmic optimization to MHD power plant design  

SciTech Connect

In the optimization of large engineering systems, complexity can introduce difficulties that are not only greater in amount than, but also different in kind from those presented by simpler systems. Behavior of the objective function may vary widely and unpredictably over the feasibility region, so that no one class of algorithms is capable of identifying the optimum. Polyalgorithmic optimization has been proposed as a way to cope with this problem. The authors have implemented an elementary polyalgorithmic strategy in GSMP, our executive program for general system modeling. Four standard nonlinear optimization algorithms are used, ordered according to the degree of local smoothness in the objective function for which they were designed. In a control section of GSMP, an estimate of that smoothness is maintained (local to the point being investigated), and an algorithm selected accordingly, taking into account the history of the optimization processes up till that time. This procedure is used to determine the optimum design of an MHD power plant with respect to minimization of the cost of electricity. Combustor pressure, combustion air preheat temperature, combustor heat loss, magnetic field of the MHD generator, the channel load factor, and the diffuser pressure recovery coefficient were selected as independent parameters.

Berry, G.F.; Cook, J.M.; Dennis, C.B.

1981-01-01

169

Parametric study of potential early commercial MHD power plants  

SciTech Connect

A parametric study was performed to determine performance and cost of moderate technology coal-fired Open Cycle MHD/steam power plant designs which can be expected to require a shorter development time and have a lower development cost than previously-considered mature OCMHD/Steam plants. Three base cases were considered: Base Case 1 had an indirectly-fired high temperature air heater (HTAH) subsystem delivering air at 2700 F; fired by a state-of-the-art atmospheric pressure gasifier; Base Case 2 had an indirectly-fired HTAH subsystem delivering air at 3000 F; in Base Case 3 the HTAH subsystem was deleted and oxygen enrichment was used to obtain requisite MHD combustion temperature. Coal pile to bus bar efficiencies in Base Case 1 ranged from 41.4% to 42.9%, and cost of electricity (COE) was highest of the three base cases. For Base Case 2 the efficiency range was 42.0% to 45.6%, and COE was lowest. For Base Case 3 the efficiency range was 42.9% to 44.4%, and COE was intermediate. The best parametric cases in Base Cases 2 and 3 are recommended for conceptual design. Eventual choice between these approaches is dependent on further evaluation of the tradeoffs among HTAH development risk, O/sub 2/ plant integration and further refinements of comparative costs.

Marston, C.H.; Alyea, F.N.; Bender, D.J.

1980-02-01

170

MHD Energy Bypass Scramjet Engine  

NASA Technical Reports Server (NTRS)

Revolutionary rather than evolutionary changes in propulsion systems are most likely to decrease cost of space transportation and to provide a global range capability. Hypersonic air-breathing propulsion is a revolutionary propulsion system. The performance of scramjet engines can be improved by the AJAX energy management concept. A magneto-hydro-dynamics (MHD) generator controls the flow and extracts flow energy in the engine inlet and a MHD accelerator downstream of the combustor accelerates the nozzle flow. A progress report toward developing the MHD technology is presented herein. Recent theoretical efforts are reviewed and ongoing experimental efforts are discussed. The latter efforts also include an ongoing collaboration between NASA, the US Air Force Research Laboratory, US industry, and Russian scientific organizations. Two of the critical technologies, the ionization of the air and the MHD accelerator, are briefly discussed. Examples of limiting the combustor entrance Mach number to a low supersonic value with a MHD energy bypass scheme are presented, demonstrating an improvement in scramjet performance. The results for a simplified design of an aerospace plane show that the specific impulse of the MHD-bypass system is better than the non-MHD system and typical rocket over a narrow region of flight speeds and design parameters. Equilibrium ionization and non-equilibrium ionization are discussed. The thermodynamic condition of air at the entrance of the engine inlet determines the method of ionization. The required external power for non-equilibrium ionization is computed. There have been many experiments in which electrical power generation has successfully been achieved by magneto-hydrodynamic (MHD) means. However, relatively few experiments have been made to date for the reverse case of achieving gas acceleration by the MHD means. An experiment in a shock tunnel is described in which MHD acceleration is investigated experimentally. MHD has several potential aerospace applications. The first is to improve the performance of hypersonic air-breathing engines for space launch and cruise vehicles. The second is to improve the performance of a high enthalpy wind tunnel. The third is to control a hypersonic vehicle. With such applications in mind, theoretical and experiments are being conducted at the NASA Ames Research Center to develop the MHD technology.

Mehta, Unmeel B.; Bogdanoff, David W.; Park, Chul; Arnold, Jim (Technical Monitor)

2001-01-01

171

Computer controlled MHD power consolidation and pulse-generation system  

SciTech Connect

The major goal of this research project is to establish the feasibility of a power conversion technology which will permit the direct synthesis of computer programmable pulse power. Feasibility will be established by demonstration of direct synthesis of commercial frequency power by means of computer control. The power input to the conversion system is assumed to be a MHD Faraday connected generator which may be viewed as a multi-terminal d.c. source. This consolidation/inversion process is referred to subsequently as Pulse-Amplitude-Synthesis-and-Control (PASC). A secondary goal is to deliver a controller subsystem consisting of a computer, software, and computer interface board which can serve as one of the building blocks for a possible phase II prototype system. This report contains discussions on the following areas: description of test transformer configurations for preliminary testing of the PASC power supply and computer control subsystems; results of test transformer testing; conclusions from preliminary testing results and new PASC configuration; control algorithms and data acquisition; feasibility demonstration testing. 16 figs.

Johnson, R.; Marcotte, K.; Donnelly, M.

1989-01-01

172

Computer controlled MHD power consolidation and pulse generation system  

SciTech Connect

The major goal of this research project is to establish the feasibility of a power conversion technology which will permit the direct synthesis of computer programmable pulse power. Feasibility has been established in this project by demonstration of direct synthesis of commercial frequency power by means of computer control. The power input to the conversion system is assumed to be a Faraday connected MHD generator which may be viewed as a multi-terminal dc source and is simulated for the purpose of this demonstration by a set of dc power supplies. This consolidation/inversion (CI), process will be referred to subsequently as Pulse Amplitude Synthesis and Control (PASC). A secondary goal is to deliver a controller subsystem consisting of a computer, software, and computer interface board which can serve as one of the building blocks for a possible phase II prototype system. This report period work summarizes the accomplishments and covers the high points of the two year project. 6 refs., 41 figs.

Johnson, R.; Marcotte, K.; Donnelly, M.

1990-01-01

173

Generation of compressible modes in MHD turbulence  

Microsoft Academic Search

Astrophysical turbulence is magnetohydrodynamic (MHD) in nature. We discuss fundamental properties of MHD turbulence and in particular the generation of compressible MHD waves by Alfvénic turbulence and show that this process is inefficient. This allows us to study the evolution of different types of MHD perturbations separately. We describe how to separate MHD fluctuations into three distinct families: Alfvén, slow,

Jungyeon Cho; A. Lazarian

2005-01-01

174

Definition of the development program for an MHD advanced power train. Volume I. Final report  

SciTech Connect

The MHD power train designs in the APT program are all aimed at early commercial use of MHD, and thus not representative of more advanced and mature MHD power systems. Accordingly, the power train design approaches in Task 2 as well as the MHD power plant designs in Task 1 were selected for early use and based on present status and experience gained in MHD technology development. Naturally, significant improvements and advancements of MHD technology can be expected after its commercial introduction like that experienced for any other new technology. The information developed in Task 1 of the APT program provided basic information for use in the subsequent task activities reported on here. One important conclusion from the work conducted in Task 1 was the selection of supersonic channel operation at a peak magnetic field strength of about 4.5 Tesla for first commercial use. An important result from the continued MHD generator performance studies conducted as part of Task 2 and reported on here was that the supersonic channel design also offers efficient operation at part load. The MHD generator channel operation at part load was found to shift to transonic and subsonic operation to maintain high efficiency as load decreases. Furthermore, the performance sensitivity analyses in Task 2 substantiated that net MHD power output (MHD generator gross power minus compressor power for oxygen production and compression of the oxygen-enriched combustion air to peak cycle pressure) is reached at the oxidizer/fuel equivalence ratio of 0.9 initially selected in Task 1, although the highest flame temperature and electrical conductivity of the gases produced in the combustor occur at a lower stoichiometry. 48 figs., 41 tabs.

Clark, J.P.; Hals, F.A.; Noble, J.H.; Muller, D.J.; Willis, P.A.

1984-12-01

175

Design of a ten megawatt rocket driven disk MHD generator  

Microsoft Academic Search

A description is given of a 10 MW rocket-driven MHD (magnetohydrodynamic) disk generator system that has been designed as part of the feasibility study of multimegawatt MHD space power systems for Strategic Defense Initiative (SDI) mission applications. The experimental system consists of a plasma generator\\/injector, a supersonic nozzle, a parallel-wall disk channel, and a diffuser. The magnetic field is provided

A. Solbes; J. Weede; R. Hession; P. Mitchell

1989-01-01

176

Explosive Magnetohydrodynamics.  

National Technical Information Service (NTIS)

Experimental studies on the production of short duration pulses of electrical power by MHD principles in a radial flow channel are presented. Plasma currents in excess of 10000 amperes were measured in a radially expanding explosive driven plasma. The pla...

M. S. Jones F. H. Webb P. Webster S. Handlin R. Harrison

1965-01-01

177

Evaluation of a candidate material for a coal-fired magnetohydrodynamic (MHD) high temperature recuperative air heater  

SciTech Connect

In order to achieve the desired efficiency in the MHD cycle, one of two procedures must be employed. The first is to inject pure oxygen during combustion in order to achieve higher combustion temperatures which will yield better conversion efficiencies. The other is to preheat the combustor air through the use of high temperature air heaters (HTAH). A recuperative air heater heats the combustor air directly by passing it through tubes which are in the exhaust gas flow before sending it into the combustor. The procedure of passing air through the furnace requires a material for the tubes which will withstand the high temperatures and corrosive environment of the furnace and should have a high heat transfer coefficient. All of the necessary properties seem to exist in ceramic materials, so ceramics have begun to be studied for high temperature air heaters as well as other high temperature applications. The present project outlines one such effort to evaluate the performance of a ceramic composite tube in a coal fired MHD facility in order to determine any changes in the tube material after exposure to high temperature and a highly corrosive environment. A recuperative high temperature air heater (HTAH) would be positioned in the radiant furnace, because the radiant furnace provides conditions comparable to an actual MHD facility and is adequate for testing HTAH materials. The temperature conditions in the furnace range from approximately 1600{degree}C to 1890{degree}C, and velocities of approximately 12 m/s to 100 m/s have been measured depending on the location in the furnace. The evaluated tube was placed in the furnace in a reducing environment with approximately 14 m/s velocity, 1650{degree}C gas temperature, and 1230{degree}C tube temperature.

Winkler, J; Dahotre, N B; Boss, W

1993-02-01

178

Downstream component corrosion in coal-fired MHD power plants  

SciTech Connect

Results are given to date of corrosion probe studies conducted to evaluate the nature and severity of degradation of oiler and superheater materials in coal-fired MHD power generation systems. Tests were conducted with two air or nitrogen cooled probes in Cell III of the UTSI MHD facility. One probe had carbon steel samples subjected to metal temperatures of from 547K to 719K and reducing (SR = 0.85) gas conditions to simulate boiler tube conditions. The exposure time to date on these samples is 240 minutes. The other probe had samples of carbon steel, chromium-molybdenum steels and stainless steels subjected to temperatures ranging from 811K to 914K with oxidizing (SR = 1.15) gas conditions. The total run time on these samples was 70 minutes. The boiler probe samples were found to undergo predominantly pitted type corrosion beneath a deposit of ash/seed material having approximately 34% K/sub 2/SO/sub 4/. Weight loss rates varied from about 1.5 x 10/sup -4/ gm/hr-cm/sup 2/ at the cool end of the probe to about 5.5 x 10/sup -4/ gm/hr-cm/sup 2/ at the hot end. This loss is attributed primarily to sulfidation by hydrogen sulfide. Resistance to scaling of superheater materials increased progressively with the degree of alloying. Attack appeared to be in the form of surface scales containing mixtures of oxides and is attributed to either gaseous oxidation or to the presence of complex potassium trisulfates.

White, M. K.

1980-06-01

179

System studies of coal fired-closed cycle MHD for central station power plants  

NASA Technical Reports Server (NTRS)

This paper presents a discussion of the closed cycle MHD results obtained in a recent study of various advanced energy conversion (ECAS) power systems. The study was part of the first phase of this ECAS study. Since this was the first opportunity to evaluate the coal fired closed cycle MHD system, a number of iterations were required to partially optimize the system. The present paper deals with the latter part of the study in which the direct coal fired, MHD topping-steam bottoming cycle was established as the current choice for central station power generation. The emphasis of the paper is on the background assumptions and the conclusions that can be drawn from the closed cycle MHD analysis. The author concludes that closed cycle MHD has efficiencies comparable to that of open cycle MHD and that both systems are considerably more efficient than the other system studies in Phase 1 of the GE ECAS. Its cost will possibly be slightly higher than that of the open cycle MHD system. Also, with reasonable fuel escalation assumptions, both systems can produce lower cost electricity than conventional steam power plants. Suggestions for further work in closed cycle MHD components and systems is made.

Zauderer, B.

1976-01-01

180

MHD-steam thermal power plant electrical stations with zero stack emission  

SciTech Connect

A system study of a combined cycle MHD-steam thermal power plant electrical station with zero stack emission through recirculation of CO{sub 2}, is presented. The design of the MHD generator of the topper is done by means of a quasi-one dimensional optimization model. The technology of the components is conventional. An overall efficiency larger than 40% for power plants with thermal power inputs above 1,000 MWth, is obtained.

Borghi, C.A.; Ribani, P.L. [Univ. of Bologna (Italy). Inst. of Electrotechnics] [Univ. of Bologna (Italy). Inst. of Electrotechnics

1996-03-01

181

A Self-Consistent Numerical Magnetohydrodynamic (MHD) Model of Helmet Streamer and Flux-Rope Interactions: Initiation and Propagation of Coronal Mass Ejections (CMEs)  

NASA Technical Reports Server (NTRS)

We present results for an investigation of the interaction of a helmet streamer arcade and a helical flux-rope emerging from the sub-photosphere. These results are obtained by using a three-dimensional axisymmetric, time-dependent ideal magnetohydrodynamic (MHD) model. Because of the physical nature of the flux-rope, we investigate two types of flux-ropes; (1) high density flux-rope (i.e. flux-rope without cavity), and (2) low density flux rope (i.e. flux-rope with cavity). When the streamer is disrupted by the flux-rope, it will evolve into a configuration resembling the typical observed loop-like Coronal Mass Ejection (CMES) for both cases. The streamer-flux rope system with cavity is easier to be disrupted and the propagation speed of the CME is faster than the streamer-flux rope system without cavity. Our results demonstrate that magnetic buoyancy force plays an important role in disrupting the streamer.

Wu, S. T.; Guo, W. P.

1997-01-01

182

A meshfree weak-strong (MWS) form method for the unsteady magnetohydrodynamic (MHD) flow in pipe with arbitrary wall conductivity  

NASA Astrophysics Data System (ADS)

In this paper a meshfree weak-strong (MWS) form method is considered to solve the coupled equations in velocity and magnetic field for the unsteady magnetohydrodynamic flow throFor this modified estimaFor this modified estimaFor this modified estimaugh a pipe of rectangular and circular sections having arbitrary conducting walls. Computations have been performed for various Hartman numbers and wall conductivity at different time levels. The MWS method is based on applying a meshfree collocation method in strong form for interior nodes and nodes on the essential boundaries and a meshless local Petrov-Galerkin method in weak form for nodes on the natural boundary of the domain. In this paper, we employ the moving least square reproducing kernel particle approximation to construct the shape functions. The numerical results for sample problems compare very well with steady state solution and other numerical methods.

Dehghan, Mehdi; Salehi, Rezvan

2013-12-01

183

MHD generator scaling analysis for baseload commercial power plants  

Microsoft Academic Search

MHD generator channel scaling analyses have been performed to definitize the effect of generator size and oxygen enrichment on channel performance. These studies have shown that MHD generator channels can be designed to operate efficiently over the range of 250 to 2135 thermal megawatts. The optimum design conditions for each of the thermal inputs were established by investigating various combinations

D. W. Swallom; C. C. P. Pian

1982-01-01

184

Coupled generator and combustor performance calculations for potential early commercial MHD power plants  

NASA Technical Reports Server (NTRS)

A parametric study of the performance of the MHD generator and combustor components of potential early commercial open-cycle MHD/steam power plants is presented. Consideration is given to the effects of air heater system concept, MHD combustor type, coal type, thermal input power, oxygen enrichment of the combustion, subsonic and supersonic generator flow and magnetic field strength on coupled generator and combustor performance. The best performance is found to be attained with a 3000 F, indirectly fired air heater, no oxygen enrichment, Illinois no. 6 coal, a two-stage cyclone combustor with 85% slag rejection, a subsonic generator, and a magnetic field configuration yielding a constant transverse electric field of 4 kV/m. Results indicate that optimum net MHD generator power is generally compressor-power-limited rather than electric-stress-limited, with optimum net power a relatively weak function of operating pressure.

Dellinger, T. C.; Hnat, J. G.; Marston, C. H.

1979-01-01

185

Local anisotropy and power spectra in magnetohydrodynamic turbulence  

NASA Astrophysics Data System (ADS)

Correlation and spectral anisotropy play important roles in solar wind and astrophysical plasmas, having significant impact on descriptions of the turbulence cascade, particle scattering, the nature of kinetic dissipation, and the transport of turbulence. Anisotropy emerges dynamically in MHD, producing stronger gradients across the large-scale mean magnetic field than along it, and occurring both globally and locally. Recently, properties of correlation anisotropy have been investigated through numerical simulations, showing the effect is intensified for more localized estimates of the mean magnetic field. The mathematical formulation of this property shows that local anisotropy mixes second-order with higher order correlations [1]. Sensitivity of local statistical estimates to higher order correlations can be understood in connection with the stochastic coordinate system inherent in such formulations. We demonstrate this in specific cases, and illustrate the connection to higher order statistics by showing the sensitivity of local anisotropy to phase randomization, after which the global measure of anisotropy is recovered at all scales of averaging. This study establishes that anisotropy of the local structure function is not a measure of anisotropy of the energy spectrum, but is rather related to higher order statistics. [1] Matthaeus et al, Astrophys. J., 750, 103 (2012)

Matthaeus, W. H.; Servidio, S.; Dmitruk, P.; Carbone, V.; Oughton, S.; Wan, M.; Osman, K. T.

2012-12-01

186

Scale Locality of Magnetohydrodynamic Turbulence  

NASA Astrophysics Data System (ADS)

We investigate the scale locality of cascades of conserved invariants at high kinetic and magnetic Reynold’s numbers in the “inertial-inductive range” of magnetohydrodynamic (MHD) turbulence, where velocity and magnetic field increments exhibit suitable power-law scaling. We prove that fluxes of total energy and cross helicity—or, equivalently, fluxes of Elsässer energies—are dominated by the contributions of local triads. Flux of magnetic helicity may be dominated by nonlocal triads. The magnetic stretching term may also be dominated by nonlocal triads, but we prove that it can convert energy only between velocity and magnetic modes at comparable scales. We explain the disagreement with numerical studies that have claimed conversion nonlocally between disparate scales. We present supporting data from a 10243 simulation of forced MHD turbulence.

Aluie, Hussein; Eyink, Gregory L.

2010-02-01

187

Economic evaluation of MHD-steam powerplants employing coal gasification  

Microsoft Academic Search

To assess the efficacy and economics of producing power from coal, four ; open-cycle magnetohydrodynamic (MHD) processing schemes were selected for study. ; Each involved a different mode of coal combustion and level of gas cleanliness. ; The options considered were: (1) coal burned in a slagging combustor; (2) ; suspension gasification with slag removal prior to combustion; (3) parallel

P. D. Bergman; J. J. Demeter; D. Bienstock

1973-01-01

188

Parametric study of potential early commercial power plants Task 3-A MHD cost analysis  

NASA Technical Reports Server (NTRS)

The development of costs for an MHD Power Plant and the comparison of these costs to a conventional coal fired power plant are reported. The program is divided into three activities: (1) code of accounts review; (2) MHD pulverized coal power plant cost comparison; (3) operating and maintenance cost estimates. The scope of each NASA code of account item was defined to assure that the recently completed Task 3 capital cost estimates are consistent with the code of account scope. Improvement confidence in MHD plant capital cost estimates by identifying comparability with conventional pulverized coal fired (PCF) power plant systems is undertaken. The basis for estimating the MHD plant operating and maintenance costs of electricity is verified.

1983-01-01

189

Double-duct liquid metal magnetohydrodynamic engine  

DOEpatents

An internal combustion, liquid metal (LM) magnetohydrodynamic (MHD) engine and an alternating current (AC) magnetohydrodynamic generator, are used in combination to provide useful AC electric energy output. The engine design has-four pistons and a double duct configuration, with each duct containing sodium potassium liquid metal confined between free pistons located at either end of the duct. The liquid metal is forced to flow back and forth in the duct by the movement of the pistons, which are alternatively driven by an internal combustion process. In the MHD generator, the two LM-MHD ducts pass in close proximity through a Hartmann duct with output transformer. AC power is produced by operating the engine with the liquid metal in the two generator ducts always flowing in counter directions. The amount of liquid metal maintained in the ducts may be varied. This provides a variable stroke length for the pistons. The engine/generator provides variable AC power at variable frequencies that correspond to the power demands of the vehicular propulsion. Also the engine should maintain nearly constant efficiency throughout the range of power usage. Automobiles and trucks could be powered by the invention, with no transmission or power converter devices being required.

Haaland, Carsten M. (Oak Ridge, TN)

1995-01-01

190

Double-duct liquid metal magnetohydrodynamic engine  

DOEpatents

An internal combustion, liquid metal (LM) magnetohydrodynamic (MHD) engine and an alternating current (AC) magnetohydrodynamic generator, are used in combination to provide useful AC electric energy output. The engine design has four pistons and a double duct configuration, with each duct containing sodium potassium liquid metal confined between free pistons located at either end of the duct. The liquid metal is forced to flow back and forth in the duct by the movement of the pistons, which are alternatively driven by an internal combustion process. In the MHD generator, the two LM-MHD ducts pass in close proximity through a Hartmann duct with output transformer. AC power is produced by operating the engine with the liquid metal in the two generator ducts always flowing in counter directions. The amount of liquid metal maintained in the ducts may be varied. This provides a variable stroke length for the pistons. The engine/generator provides variable AC power at variable frequencies that correspond to the power demands of the vehicular propulsion. Also the engine should maintain nearly constant efficiency throughout the range of power usage. Automobiles and trucks could be powered by the invention, with no transmission or power converter devices being required.

Haaland, Carsten M. (Oak Ridge, TN)

1997-01-01

191

Magnetohydrodynamic commercial plant study  

SciTech Connect

The Energy Conversion Alternatives Study (ECAS) identified magnetohydrodynamics as a highly efficient, low polluting energy alternative with a high potential for producing the lowest cost of electricity from coal. Commercialization of this process is anticipated in the mid-1990's. The combined output from the MHD generator and the steam plant is expected to give overall energy conversion efficiencies of approximately 50 percent. It is this efficiency improvement that is the important factor behind MHD development. 6 refs.

Bozzuto, C.R.; Clark, J.P.

1980-01-01

192

AC magnetohydrodynamic microfluidic switch  

SciTech Connect

A microfluidic switch has been demonstrated using an AC Magnetohydrodynamic (MHD) pumping mechanism in which the Lorentz force is used to pump an electrolytic solution. By integrating two AC MHD pumps into different arms of a Y-shaped fluidic circuit, flow can be switched between the two arms. This type of switch can be used to produce complex fluidic routing, which may have multiple applications in {micro}TAS.

Lemoff, A V; Lee, A P

2000-03-02

193

A summary of the ECAS MHD power plant results  

NASA Technical Reports Server (NTRS)

The performance and the cost of electricity (COE) for MHD systems utilizing coal or coal derived fuels are summarized along with a conceptual open cycle MHD plant design. The results show that open cycle coal fired recuperatively preheated MHD systems have potentially one of the highest coal-pile-to-bus bar efficiencies (48.3%) and also one of the lowest COE of the systems studied. Closed cycle, inert gas systems do not appear to have the potential of exceeding the efficiency of or competing with the COE of advanced steam plants.

Seikel, G. R.; Harris, L. P.

1976-01-01

194

Investigation into the commercial application of first generation MHD power plants to the aluminum industry  

Microsoft Academic Search

The United States has embarked on an ambitious program to develop open-cycle, coal-fired MHD-topped steam power generation plants to commercialization by the end of this century. The results of a study on the commercial application of the first generation MHD power plants to the aluminum industry are reported. The basic processes and energy requirements of the aluminium industry are reviewed,

M. T. Dooley; L. D. Carter

1978-01-01

195

Efficient magnetohydrodynamic simulations on graphics processing units with CUDA  

NASA Astrophysics Data System (ADS)

Magnetohydrodynamic (MHD) simulations based on the ideal MHD equations have become a powerful tool for modeling phenomena in a wide range of applications including laboratory, astrophysical, and space plasmas. In general, high-resolution methods for solving the ideal MHD equations are computationally expensive and Beowulf clusters or even supercomputers are often used to run the codes that implemented these methods. With the advent of the Compute Unified Device Architecture (CUDA), modern graphics processing units (GPUs) provide an alternative approach to parallel computing for scientific simulations. In this paper we present, to the best of the author's knowledge, the first implementation of MHD simulations entirely on GPUs with CUDA, named GPU-MHD, to accelerate the simulation process. GPU-MHD supports both single and double precision computations. A series of numerical tests have been performed to validate the correctness of our code. Accuracy evaluation by comparing single and double precision computation results is also given. Performance measurements of both single and double precision are conducted on both the NVIDIA GeForce GTX 295 (GT200 architecture) and GTX 480 (Fermi architecture) graphics cards. These measurements show that our GPU-based implementation achieves between one and two orders of magnitude of improvement depending on the graphics card used, the problem size, and the precision when comparing to the original serial CPU MHD implementation. In addition, we extend GPU-MHD to support the visualization of the simulation results and thus the whole MHD simulation and visualization process can be performed entirely on GPUs.

Wong, Hon-Cheng; Wong, Un-Hong; Feng, Xueshang; Tang, Zesheng

2011-10-01

196

Analyses Of Underwater Magnetohydrodynamic Propulsion  

Microsoft Academic Search

Sea water magnetohydrodynamic (MHD) propulsion for marine vehicles offers many unique features. There is no need for propellers, and therefore no noise associated that. Gear reduction system for the shafts is thus no longer needed. It offers maneuverbility by directional thrusts along with quietness. The theories of MHD pump jet propulsion are discussed in detail in this paper. A so-called

J. B. Gilbertt; T. F. Lint

1990-01-01

197

MHD contractors' review meeting  

NASA Astrophysics Data System (ADS)

The following research programs on magnetohydrodynamic conversion were described at the contractors' review meeting: MHD integrated topping cycle project; Activity summary for DOE's component development and integration facility; MHD bottoming cycle component testing at the coal fired flow facility; MHD heat recovery seed recovery system development; Diagnostic development and support of MHD test facilities; Heat and seed recovery technology project; TRW Econoseed process for MHD seed recovery and regeneration; and MIT magnet. Papers describe the objectives, the work to date, and results obtained. Papers have been processed separately for inclusion on the data base.

198

MHD contractors' review meeting  

SciTech Connect

The following research programs on magnetohydrodynamic conversion were described at the contractors' review meeting: MHD integrated topping cycle project; Activity summary for DOE's component development and integration facility; MHD bottoming cycle component testing at the coal fired flow facility; MHD heat recovery seed recovery system development; Diagnostic development and support of MHD test facilities; Heat and seed recovery technology project; TRW Econoseed process for MHD seed recovery and regeneration; and MIT magnet. Papers describe the objectives, the work to date, and results obtained. Papers have been processed separately for inclusion on the data base. (CK)

Not Available

1991-01-01

199

Direct Energy Conversion Fission Reactor, Gaseous Core Reactor with Magnetohydrodynamic (MHD) Generator; Final Report - Part I and Part II  

SciTech Connect

This report focuses on the power conversion cycle and efficiency. The technical issues involving the ionization mechanisms, the power management and distribution and radiation shielding and safety will be discussed in future reports.

Samim Anghaie; Blair Smith; Travis Knight

2002-11-12

200

MHD program plan, FY 1991  

NASA Astrophysics Data System (ADS)

The current magnetohydrodynamic MHD program being implemented is a result of a consensus established in public meetings held by the Department of Energy in 1984. The public meetings were followed by the formulation of a June 1984 Coal-Fired MHD Preliminary Transition and Program Plan. This plan focused on demonstrating the proof-of-concept (POC) of coal-fired MHD electric power plants by the early 1990s. MHD test data indicate that while there are no fundamental technical barriers impeding the development of MHD power plants, technical risk remains. To reduce the technical risk three key subsystems (topping cycle, bottoming cycle, and seed regeneration) are being assembled and tested separately. The program does not require fabrication of a complete superconducting magnet, but rather the development and testing of superconductor cables. The topping cycle system test objectives can be achieved using a conventional iron core magnet system already in place at a DOE facility. Systems engineering-derived requirements and analytical modeling to support scale-up and component design guide the program. In response to environmental, economic, engineering, and utility acceptance requirements, design choices and operating modes are tested and refined to provide technical specifications for meeting commercial criteria. These engineering activities are supported by comprehensive and continuing systems analyses to establish realistic technical requirements and cost data. Essential elements of the current program are to: develop technical and environmental data for the integrated MHD topping cycle and bottoming cycle systems through POC testing (1000 and 4000 hours, respectively); design, construct, and operate a POC seed regeneration system capable of processing spent seed materials from the MHD bottoming cycle; prepare conceptual designs for a site specific MHD retrofit plant; and continue supporting research necessary for system testing.

1990-10-01

201

Compendium of MHD-related terminology  

SciTech Connect

The magnetohydrodynamic (MHD) researchers in the United States have joined together in the past few years to prove the viability of the technology. As new designs for hardware methods of operation, approaches for data analysis, and levels of understanding have been atained, a set of MHD-unique terminology has been developed but not always documented. A glossary of terminology unique to the study of MHD was compiled for SEAM 27 to provide an information source for workers in this field and to assist those interested in the commercial potential of MHD in reading and understanding technical articles on the subject. The terminology defined was primarily related to the US proof-of-concept program of MHD development and eventual retrofitting of a coal fired plant with MHD equipment. Basic theoretical terms as well as terminology related to the commercialization of MHD were presented. Emphasis was placed on terms related to commercialization and those related to currently active areas of study. This paper builds on the SEAM 27 contribution. Areas of concentration in this paper are retrofit/power plant terminology, advanced measurement technology applicable to MHD, research sites. 3 refs., 1 figs.

Hart, A.T.; Lofftus, D.A.; Rudberg, D.A. (MSE, Inc., Butte, MT (USA)); Green, R.A. (Mississippi State Univ., Mississippi State, MS (USA))

1990-01-01

202

The MHD/steam combined cycle power plant; A technology update  

SciTech Connect

The MHD/steam combined cycle power plant concept involves burning fossil fuel at high temperatures ({approximately}5000 F), generating power with an MHD generator from the high temperature exhaust products and using a steam plant for conversion of the remaining thermal energy to electricity. The MHD portion is called the topping cycle and the steam plant is called the bottoming cycle. Conversion efficiency of the MHD generator is much higher than a steam cycle, typically 85-90%. SO{sub 2} can be reduced to a few parts per billion if desired and NO{sub x} can be reduced to 15-20% of current New Source Performance Standards. The purpose of this paper is to report the current status of development of the technology needed for the commercialization of plants using this concept.

Johanson, N.R.; Attig, R.C.; Champman, J.N. (Tennessee Univ., Tullahoma, TN (United States). Space Inst.)

1990-01-01

203

Magnetohydrodynamic propulsion of ships.  

National Technical Information Service (NTIS)

Magnetohydrodynamic (MHD) propulsion of ships has been studied by scientists and technicians since the early 1960's. The major reason for the interest is the potential for a high energy efficiency and low noise propulsion. The report gives a brief introdu...

B. Wolff

1990-01-01

204

Ultrahigh temperature vapor core reactor-MHD system for space nuclear electric power  

NASA Technical Reports Server (NTRS)

The conceptual design of a nuclear space power system based on the ultrahigh temperature vapor core reactor with MHD energy conversion is presented. This UF4 fueled gas core cavity reactor operates at 4000 K maximum core temperature and 40 atm. Materials experiments, conducted with UF4 up to 2200 K, demonstrate acceptable compatibility with tungsten-molybdenum-, and carbon-based materials. The supporting nuclear, heat transfer, fluid flow and MHD analysis, and fissioning plasma physics experiments are also discussed.

Maya, Isaac; Anghaie, Samim; Diaz, Nils J.; Dugan, Edward T.

1991-01-01

205

Distinguishing characteristics of a steam generator for power stations with a magnetohydrodynamic generator  

Microsoft Academic Search

A steam generator for MHD power stations differs from a normal type steam generator in the following chief ways: (1) it does not possess its own fuel arrangement (in a normal mode of operation) and operates in the range of temperatures up to 1500°C on high-temperature products of incomplete combustion which contain an ionizing seed; (2) in addition to the

G. N. Morozov; I. L. Mostinskii; Y. I. Rabkin; S. A. Tager

1977-01-01

206

MHD can clean up the environment  

Microsoft Academic Search

Magnetohydrodynamics (MHD) involves interactions among electromagnetic fields and electrically conducting gases and liquids. The most developed application for MM in the United States is for central station electric power generation using a coal-fired combined cycle system. Proof-of-Concept (POC) scale demonstration of the downstream components used in this technology is currently being carried out at the US Department of Energy`s (DOE)

A. C. Sheth; L. W. Crawford; J. K. Holt

1993-01-01

207

MHD can clean up the environment  

Microsoft Academic Search

Magnetohydrodynamics (MHD) involves interactions among electromagnetic fields and electrically conducting gases and liquids. The most developed application for MM in the United States is for central station electric power generation using a coal-fired combined cycle system. Proof-of-Concept (POC) scale demonstration of the downstream components used in this technology is currently being carried out at the US Department of Energy's (DOE)

A. C. Sheth; L. W. Crawford; J. K. Holt

1993-01-01

208

Closed Cycle Magnetohydrodynamic Nuclear Space Power Generation Using Helium/Xenon Working Plasma  

NASA Technical Reports Server (NTRS)

A multimegawatt-class nuclear fission powered closed cycle magnetohydrodynamic space power plant using a helium/xenon working gas has been studied, to include a comprehensive system analysis. Total plant efficiency was expected to be 55.2 percent including pre-ionization power. The effects of compressor stage number, regenerator efficiency, and radiation cooler temperature on plant efficiency were investigated. The specific mass of the power generation plant was also examined. System specific mass was estimated to be 3 kg/kWe for a net electrical output power of 1 MWe, 2-3 kg/kWe at 2 MWe, and approx.2 kg/KWe at >3 MWe. Three phases of research and development plan were proposed: (1) Phase I-proof of principle, (2) Phase II-demonstration of power generation, and (3) Phase III-prototypical closed loop test.

Litchford, R. J.; Harada, N.

2005-01-01

209

Relaxation model for extended magnetohydrodynamics: Comparison to magnetohydrodynamics for dense Z-pinches  

SciTech Connect

It is shown that the two-fluid model under a generalized Ohm's law formulation and the resistive magnetohydrodynamics (MHD) can both be described as relaxation systems. In the relaxation model, the under-resolved stiff source terms constrain the dynamics of a set of hyperbolic equations to give the correct asymptotic solution. When applied to the collisional two-fluid model, the relaxation of fast time scales associated with displacement current and finite electron mass allows for a natural transition from a system where Ohm's law determines the current density to a system where Ohm's law determines the electric field. This result is used to derive novel algorithms, which allow for multiscale simulation of low and high frequency extended-MHD physics. This relaxation formulation offers an efficient way to implicitly advance the Hall term and naturally simulate a plasma-vacuum interface without invoking phenomenological models. The relaxation model is implemented as an extended-MHD code, which is used to analyze pulsed power loads such as wire arrays and ablating foils. Two-dimensional simulations of pulsed power loads are compared for extended-MHD and MHD. For these simulations, it is also shown that the relaxation model properly recovers the resistive-MHD limit.

Seyler, C. E. [School of Electrical and Computer Engineering, Cornell University, Ithaca, New York 14853 (United States); Martin, M. R. [Sandia National Laboratories, Albuquerque, New Mexico 87123 (United States)

2011-01-15

210

Priority pollutant analysis of MHD-derived combustion products  

NASA Astrophysics Data System (ADS)

An important factor in developing Magnetohydrodynamics (MHD) for commercial applications is environmental impact. Consequently, an effort was initiated to identify and quantify any possible undesirable minute chemical constituents in MHD waste streams, with special emphasis on the priority pollutant species. This paper discusses how priority pollutant analyses were used to accomplish the following goals at the University of Tennessee Space Institute (UTSI): comparison of the composition of solid combustion products collected from various locations along a prototypical MHD flow train during the firing of Illinois No. 6 and Montana Rosebud coals; comparison of solid waste products generated from MHD and conventional power plant technologies; and identification of a suitable disposal option for various MHD derived combustion products. Results from our ongoing research plans for gas phase sampling and analysis of priority pollutant volatiles, semi-volatiles, and metals are discussed.

Parks, Katherine D.

211

Solar-Driven Liquid-Metal MHD Generator  

NASA Technical Reports Server (NTRS)

Liquid-metal magnetohydrodynamic (MHD) power generator with solar oven as its heat source has potential to produce electric power in space and on Earth at high efficiency. Generator focuses radiation from Sun to heat driving gas that pushes liquid metal past magnetic coil. Power is extracted directly from electric currents set up in conducting liquid. Using solar energy as fuel can save considerable costs and payload weight, compared to previous systems.

Hohl, F.; Lee, J. H.

1982-01-01

212

Coal-gasification/MHD/steam-turbine combined-cycle (GMS) power generation  

NASA Astrophysics Data System (ADS)

Advantages of a clean fuel system are presented and include the elimination of mineral matter or slag from all components other than the coal gasifier and gas cleanup system; reduced wear and corrosion on components; and increased seed recovery resulting from reduced exposure of seed to mineral matter or slag. Efficiencies in some specific GMS power plants were shown to be higher than for a comparably sized coal burning MHD power plant. The use of energy from the MHD exhaust gas to gasify coal (rather than the typical approach of burning part of the coal) results in these higher efficiencies.

Lytle, J. M.; Marchant, D. D.

1980-11-01

213

Experiments and numerical simulations on high-density magnetohydrodynamic electrical power generation  

NASA Astrophysics Data System (ADS)

We describe experiments and numerical simulations on high-density energy conversion using a compact closed-cycle magnetohydrodynamic electrical power generator, where shock-tube-based experiments and quasi-three-dimensional numerical simulations are fully coupled. The temporal plasma-fluid behavior, the one- and two-dimensional plasma-fluid structures, the enthalpy-entropy diagram, the Hall voltage-Hall current characteristics, and the quality of the energy conversion efficiency are investigated. The slightly divergent channel configuration, the application of high- and uniform-density magnetic flux to the entire generator, the high electrical conductivity, the symmetric plasma structure and stable plasma behavior, and the sufficient pressure gradient used to drive the fluid overcome the disadvantages of the generator due to its compactness, and markedly improve its energy conversion performance, namely, a power density of 0.76 GW/m3, an isentropic efficiency of 51%, and an enthalpy extraction ratio of 17.0%.

Murakami, Tomoyuki; Okuno, Yoshihiro

2008-09-01

214

Experiments and numerical simulations on high-density magnetohydrodynamic electrical power generation  

SciTech Connect

We describe experiments and numerical simulations on high-density energy conversion using a compact closed-cycle magnetohydrodynamic electrical power generator, where shock-tube-based experiments and quasi-three-dimensional numerical simulations are fully coupled. The temporal plasma-fluid behavior, the one- and two-dimensional plasma-fluid structures, the enthalpy-entropy diagram, the Hall voltage-Hall current characteristics, and the quality of the energy conversion efficiency are investigated. The slightly divergent channel configuration, the application of high- and uniform-density magnetic flux to the entire generator, the high electrical conductivity, the symmetric plasma structure and stable plasma behavior, and the sufficient pressure gradient used to drive the fluid overcome the disadvantages of the generator due to its compactness, and markedly improve its energy conversion performance, namely, a power density of 0.76 GW/m{sup 3}, an isentropic efficiency of 51%, and an enthalpy extraction ratio of 17.0%.

Murakami, Tomoyuki; Okuno, Yoshihiro [Department of Energy Sciences, Tokyo Institute of Technology, 4259-G3-38, Nagatsuta, Midori-ku, Yokohama 226-8502 (Japan)

2008-09-15

215

H2OTSTUF: Appropriate Operating Regimes for Magnetohydrodynamic Augmentation  

NASA Technical Reports Server (NTRS)

A trade study of magnetohydrodynamic (MHD) augmented propulsion reveals a unique operating regime at lower thrust levels. Substantial mass savings are realized over conventional chemical, solar, and electrical propulsion concepts when MHD augmentation is used to obtain optimal I(sub sp). However, trip times for the most conservative estimates of power plant specific impulse and accelerator efficiency may be prohibitively long. Quasi-one-dimensional calculations show that a solar or nuclear thermal system augmented by MHD can provide competitive performance while utilizing a diverse range of propellants including water, which is available from the Space Shuttle, the Moon, asteroids, and various moons and planets within our solar system. The use of in-situ propellants will reduce costs of space operations as well as enable human exploration of our Solar System. The following conclusions can be drawn from the results of the mission trade study: (1) There exists a maximum thrust or mass flow rate above which MHD augmentation increases the initial mass in low earth orbit (LEO); (2) Mass saving of over 50% can be realized for unique combination of solar/MHD systems; (3) Trip times for systems utilizing current power supply technology may be prohibitively long. Theoretical predictions of MHD performance for in space propulsion systems show that improved efficiencies can reduce trip times to acceptable levels; (4) Long trip times indicative of low thrust systems can be shortened by an increase in the MHD accelerator efficiency or a decrease in the specific mass of the power supply and power processing unit; and (5) As for all propulsion concepts, missions with larger (Delta)v's benefit more from the increased specific impulse resulting from MHD augmentation. Using a quasi-one-dimensional analysis, the required operating conditions for a MHD accelerator to reach acceptable efficiencies are outlined. This analysis shows that substantial non-equilibrium ionization is desirable.

Jones, Jonathan E.; Hawk, Clark W.

1998-01-01

216

Estimates of Optimal Operating Conditions for Hydrogen-Oxygen Cesium-Seeded Magnetohydrodynamic Power Generator  

NASA Technical Reports Server (NTRS)

The value of percent seed, oxygen to fuel ratio, combustion pressure, Mach number, and magnetic field strength which maximize either the electrical conductivity or power density at the entrance of an MHD power generator was obtained. The working fluid is the combustion product of H2 and O2 seeded with CsOH. The ideal theoretical segmented Faraday generator along with an empirical form found from correlating the data of many experimenters working with generators of different sizes, electrode configurations, and working fluids, are investigated. The conductivity and power densities optimize at a seed fraction of 3.5 mole percent and an oxygen to hydrogen weight ratio of 7.5. The optimum values of combustion pressure and Mach number depend on the operating magnetic field strength.

Smith, J. M.; Nichols, L. D.

1977-01-01

217

Methods of reducing energy consumption of the oxidant supply system for MHD\\/steam power plants  

Microsoft Academic Search

An in-depth study was conducted to identify possible improvements to the oxidant supply system for combined cycle MHD power plants which would lead to higher thermal efficiency and reduction in the cost of electricity, COE. Results showed that the oxidant system energy consumption could be minimized when the process was designed to deliver a product O2 concentration of 70 mole

A. J. Juhasz

1983-01-01

218

User's Manual for the UTSI MHD\\/steam power plant Systems Code  

Microsoft Academic Search

This report is a User's Manual for the UTSI Systems Code for analysis of the cost\\/performance of combined cycle MHD steam power plants. In addition to the original code, it contains the NASA SP-273 code for chemical equilibrium calculations and PRESTO steam plant code which was originated by the General Electric Company and modified by Oak Ridge National Laboratories and

J. N. Chapman; E. H. Kiessling; M. C. Altstatt; C. D. Prather

1985-01-01

219

Critical Contributions in MHD Power Generation. Quarterly Technical Progress Report, December 1, 1976--February 28, 1977.  

National Technical Information Service (NTIS)

Research progress in open-cycle coal-fired MHD power generation at Massachusetts Institute of Technology (MIT) is reported. The scope and objectives of the MIT program are to: (1) Establish chemical, thermal, and electrical data to guide materials selecti...

J. F. Louis

1977-01-01

220

Off-design study of an open cycle MHD power plant with oxygen enrichment  

SciTech Connect

This paper undertakes to explore some of the more important aspects of off-design operation for an MHD power plant. An essential requirement is that the plant be designed to meet part-load and overload conditions. Furthermore, the optimal design should be subject to a specified load demand curve. For off-design regimes, an analysis is made to determine the compatible joint operating conditions for an MHD topping cycle, a steam bottoming plant, a turbine train, a compressor, and an oxygen separation plant. The analysis performed is subject to constraints (e.g. metal temperatures, second law violations, component performance requirements, environmental considerations).

Geyer, H.K.; Berry, G.F.

1981-01-01

221

Prospects for energy recovering from plastic waste gasificators by means of MHD topping cycle  

Microsoft Academic Search

In this paper the authors analyse their proposal consisting of equipping a plastic waste gasification plant both with a conventional steam power plant and magnetohydrodynamic (MHD) topping cycle. One of the major advantages of this technique is the neutralization of the acid gases present in the fumes accomplished by the alkaline cations deriving from the salt used for plasma seeding.

A. Geri; N. Verdone; Alessandro Salvini

1997-01-01

222

Thermodynamic Cycle Analysis of Magnetohydrodynamic-Bypass Hypersonic Airbreathing Engines  

NASA Technical Reports Server (NTRS)

The prospects for realizing a magnetohydrodynamic (MHD) bypass hypersonic airbreathing engine are examined from the standpoint of fundamental thermodynamic feasibility. The MHD-bypass engine, first proposed as part of the Russian AJAX vehicle concept, is based on the idea of redistributing energy between various stages of the propulsion system flow train. The system uses an MHD generator to extract a portion of the aerodynamic heating energy from the inlet and an MHD accelerator to reintroduce this power as kinetic energy in the exhaust stream. In this way, the combustor entrance Mach number can be limited to a specified value even as the flight Mach number increases. Thus, the fuel and air can be efficiently mixed and burned within a practical combustor length, and the flight Mach number operating envelope can be extended. In this paper, we quantitatively assess the performance potential and scientific feasibility of MHD-bypass engines using a simplified thermodynamic analysis. This cycle analysis, based on a thermally and calorically perfect gas, incorporates a coupled MHD generator-accelerator system and accounts for aerodynamic losses and thermodynamic process efficiencies in the various engin components. It is found that the flight Mach number range can be significantly extended; however, overall performance is hampered by non-isentropic losses in the MHD devices.

Litchford, R. J.; Cole, J. W.; Bityurin, V. A.; Lineberry, J. T.

2000-01-01

223

The infinite interface limit of multiple-region relaxed magnetohydrodynamics  

SciTech Connect

We show the stepped-pressure equilibria that are obtained from a generalization of Taylor relaxation known as multi-region, relaxed magnetohydrodynamics (MRXMHD) are also generalizations of ideal magnetohydrodynamics (ideal MHD). We show this by proving that as the number of plasma regions becomes infinite, MRXMHD reduces to ideal MHD. Numerical convergence studies illustrating this limit are presented.

Dennis, G. R.; Dewar, R. L.; Hole, M. J. [Research School of Physics and Engineering, Australian National University, ACT 0200 (Australia); Hudson, S. R. [Princeton Plasma Physics Laboratory, P.O. Box 451, Princeton, New Jersey 08543 (United States)

2013-03-15

224

Results from study of potential early commercial MHD power plants and from recent ETF design work  

Microsoft Academic Search

The study deals with different 'moderate technology' entry-level commercial MHD power plants. Two of the reference plants are based on combustion of coal with air preheated in a high-temperature regenerative air heater separately fired with a low-BTU gas produced in a gasifier integrated with the power plant. The third reference plant design is based on the use of oxygen enriched

F. Hals; R. Kessler; D. Swallom; L. Westra; J. Zar; W. Morgan; C. Bozzuto

1980-01-01

225

The magnetohydrodynamics of cometary plasma  

Microsoft Academic Search

Understanding of the cometary plasma environment, an ideal laboratory for magnetohydrodynamic (MHD) study, has great value in plasma physics. This dissertation presents a collection of 3-D global mass-loaded ideal MHD studies of this environment with a multi-scale grid system resolving both the bow shock and contact surface. Using the single and multi-species versions of this model as well as steady-state

Ying-Dong Jia

2007-01-01

226

Magnetohydrodynamics with Anisotropic Ion Pressure  

NASA Astrophysics Data System (ADS)

To simulate the pressure anisotropy of space plasmas, we extended the global magnetohydrodynamics (MHD) model BATS-R-US based on the study of MHD with anisotropic ion pressure and isotropic electron pressure under both the classical and semirelativistic approximation. We derived the characteristic wave speeds for determining time steps and calculating numerical fluxes. Simulations of the Earth's magnetosphere validated the model's ability to reproduce the pressure anisotropy in the magnetosheath.

Meng, X.; Tóth, G.; Gombosi, T. I.

2012-07-01

227

The MHD/steam combined cycle power plant: A technology update  

SciTech Connect

The MHD/steam combined cycle power plant concept involves burning fossil fuel at high temperatures ({approximately}5000 F), generating power with an MHD generator from the high temperature exhaust products and using a steam plant for conversion of the remaining thermal energy to electricity. The MHD portion is called the topping cycle and the steam plant is called the bottoming cycle. The system uses potassium seed, burned with coal and preheated and/or oxygen enriched air to achieve temperatures sufficient to provide some electrical conductivity in the combustion products by thermal ionization of the potassium atoms. conversion efficiency of the MHD generator is much higher that a steam cycle, typically 85--90%. The appeal of the combined cycle plant is much higher overall plant efficiency than other known technologies (up to about 55% in the mature plant), inherent control of SO2, NOx and particulates. SO2 can be reduced to a few parts per billion if desired and NOx can be reduced to 15--20% of current New Source Performance Standards. The purpose of this paper is to report the current status of development of the technology needed for the commercialization of plants using this concept. 9 refs., 11 figs.

Johanson, N.R.; Attig, R.C.; Chapman, J.N.

1990-01-01

228

Results from a large-scale MHD propulsion experiment.  

National Technical Information Service (NTIS)

Magnetohydrodynamic (MHD) thrusters have long been recognized as potentially attractive candidates for ship propulsion because such systems eliminate the conventional rotating drive components. The MHD thruster is essentially an electromagnetic (EM) pump ...

M. Petrick J. Libera J. X. Bouillard E. S. Pierson D. Hill

1992-01-01

229

KIVA-I Extended Duration MHD Generator Development.  

National Technical Information Service (NTIS)

An extended duration magnetohydrodynamic (MHD) generator system was developed. This system consists of the MHD combustor, nozzle, generator channel, diffuser, high speed data acquisition system and high voltage converter. Two steady-state generator channe...

H. W. Hehn J. K. Lytle L. W. Buechler R. A. Nimmo R. V. Shanklin

1975-01-01

230

Three-Dimensional Numerical Modeling of Magnetohydrodynamic Augmented Propulsion Experiment  

NASA Technical Reports Server (NTRS)

Over the past several years, NASA Marshall Space Flight Center has engaged in the design and development of an experimental research facility to investigate the use of diagonalized crossed-field magnetohydrodynamic (MHD) accelerators as a possible thrust augmentation device for thermal propulsion systems. In support of this effort, a three-dimensional numerical MHD model has been developed for the purpose of analyzing and optimizing accelerator performance and to aid in understanding critical underlying physical processes and nonideal effects. This Technical Memorandum fully summarizes model development efforts and presents the results of pretest performance optimization analyses. These results indicate that the MHD accelerator should utilize a 45deg diagonalization angle with the applied current evenly distributed over the first five inlet electrode pairs. When powered at 100 A, this configuration is expected to yield a 50% global efficiency with an 80% increase in axial velocity and a 50% increase in centerline total pressure.

Turner, M. W.; Hawk, C. W.; Litchford, R. J.

2009-01-01

231

Performance calculations for 200-1000 MWe MHD/steam power plants  

NASA Technical Reports Server (NTRS)

The effects of MHD generator length, level of oxygen enrichment, and oxygen production power on the performance of MHD/steam power plants ranging from 200 to 1000 MW in electrical output are investigated. The plants considered use oxygen enriched combustion air preheated to 1100 F. Both plants in which the MHD generator is cooled with low temperature and pressure boiler feedwater and plants in which the generator is cooled with high temperature and pressure boiler feedwater are considered. For plants using low temperature boiler feedwater for generator cooling the maximum thermodynamic efficiency is obtained with shorter generators and a lower level of oxygen enrichment compared to plants using high temperature boiler feedwater for generator cooling. The generator length at which the maximum plant efficiency occurs increases with power plant size for plants with a generator cooled by low temperature feedwater. Also shown is the relationship of the magnet stored energy requirement of the generator length and the power plant performance. Possible cost/performance tradeoffs between magnet cost and plant performance are indicated.

Staiger, P. J.

1981-01-01

232

Performance calculations for 200-1000 MWe MHD/steam power plants  

SciTech Connect

The effects of MHD generator length, level of oxygen enrichment, and oxygen production power on the performance of MHD/steam power plants ranging from 200 to 1000 MW in electrical output are investigated. The plants considered use oxygen enriched combustion air preheated to 1100/sup 0/F. Both plants in which the MHD generator is cooled with low temperature and pressure boiler feedwater and plants in which the generator is cooled with high temperature and pressure boiler feedwater are considered. It is shown that for plants using low temperature boiler feedwater for generator cooling the maximum thermodynamic efficiency is obtained with shorter generator and a lower level of oxygen enrichment compared to plants using high temperature boiler feedwater for generator cooling. It is also shown that the generator length at which the maximum plant efficiency occurs increases with power plant size for plants with a generator cooled by low temperature feedwater. Also shown is the relationship of the magnet stored energy requirement to the generator length and the power plant performance. Possible cost/performance tradeoffs between magnet cost and plant performance are indicated.

Staiger, P.J.

1981-01-01

233

Multi-region relaxed magnetohydrodynamics with flow  

NASA Astrophysics Data System (ADS)

We present an extension of the multi-region relaxed magnetohydrodynamics (MRxMHD) equilibrium model that includes plasma flow. This new model is a generalization of Woltjer's model of relaxed magnetohydrodynamics equilibria with flow. We prove that as the number of plasma regions becomes infinite, our extension of MRxMHD reduces to ideal MHD with flow. We also prove that some solutions to MRxMHD with flow are not time-independent in the laboratory frame, and instead have 3D structure which rotates in the toroidal direction with fixed angular velocity. This capability gives MRxMHD potential application to describing rotating 3D MHD structures such as "snakes" and long-lived modes.

Dennis, G. R.; Hudson, S. R.; Dewar, R. L.; Hole, M. J.

2014-04-01

234

Optimization of the oxidant supply system for combined cycle MHD power plants  

NASA Technical Reports Server (NTRS)

An in-depth study was conducted to determine what, if any, improvements could be made on the oxidant supply system for combined cycle MHD power plants which could be reflected in higher thermal efficiency and a reduction in the cost of electricity, COE. A systematic analysis of air separation process varitions which showed that the specific energy consumption could be minimized when the product stream oxygen concentration is about 70 mole percent was conducted. The use of advanced air compressors, having variable speed and guide vane position control, results in additional power savings. The study also led to the conceptual design of a new air separation process, sized for a 500 MW sub e MHD plant, referred to a internal compression is discussed. In addition to its lower overall energy consumption, potential capital cost savings were identified for air separation plants using this process when constructed in a single large air separation train rather than multiple parallel trains, typical of conventional practice.

Juhasz, A. J.

1982-01-01

235

Optimization of the oxidant supply system for combined cycle MHD power plants  

NASA Astrophysics Data System (ADS)

An in-depth study was conducted to determine what, if any, improvements could be made on the oxidant supply system for combined cycle MHD power plants which could be reflected in higher thermal efficiency and a reduction in the cost of electricity, COE. A systematic analysis of air separation process varitions which showed that the specific energy consumption could be minimized when the product stream oxygen concentration is about 70 mole percent was conducted. The use of advanced air compressors, having variable speed and guide vane position control, results in additional power savings. The study also led to the conceptual design of a new air separation process, sized for a 500 MW sub e MHD plant, referred to a internal compression is discussed. In addition to its lower overall energy consumption, potential capital cost savings were identified for air separation plants using this process when constructed in a single large air separation train rather than multiple parallel trains, typical of conventional practice.

Juhasz, A. J.

236

Magneto-Hydrodynamics Based Microfluidics  

PubMed Central

In microfluidic devices, it is necessary to propel samples and reagents from one part of the device to another, stir fluids, and detect the presence of chemical and biological targets. Given the small size of these devices, the above tasks are far from trivial. Magnetohydrodynamics (MHD) offers an elegant means to control fluid flow in microdevices without a need for mechanical components. In this paper, we review the theory of MHD for low conductivity fluids and describe various applications of MHD such as fluid pumping, flow control in fluidic networks, fluid stirring and mixing, circular liquid chromatography, thermal reactors, and microcoolers.

Qian, Shizhi; Bau, Haim H.

2009-01-01

237

Results from conceptual design study of potential early commercial MHD/steam power plants  

NASA Technical Reports Server (NTRS)

This paper presents conceptual design information for a potential early MHD power plant developed in the second phase of a joint study of such plants. Conceptual designs of plant components and equipment with performance, operational characteristics and costs are reported on. Plant economics and overall performance including full and part load operation are reviewed. Environmental aspects and the methods incorporated in plant design for emission control of sulfur and nitrogen oxides are reviewed. Results from reliability/availability analysis conducted are also included.

Hals, F.; Kessler, R.; Swallom, D.; Westra, L.; Zar, J.; Morgan, W.; Bozzuto, C.

1981-01-01

238

Induction-drive magnetohydrodynamic propulsion  

Microsoft Academic Search

The use of magnetohydrodynamic propulsion for marine applications is reviewed with emphasis on induction-drive systems such as the “ripple” motor. Comparisons are made with direct-drive MHD propulsion systems. Application to pumps for hazardous fluids and liquid-metal coolants are also discussed.

D. L. Mitchell; D. U. Gubser

1993-01-01

239

Results from study of potential early commercial MHD power plants and from recent ETF design work  

NASA Astrophysics Data System (ADS)

The study deals with different 'moderate technology' entry-level commercial MHD power plants. Two of the reference plants are based on combustion of coal with air preheated in a high-temperature regenerative air heater separately fired with a low-BTU gas produced in a gasifier integrated with the power plant. The third reference plant design is based on the use of oxygen enriched combustion air. Performance calculations show that an overall power plant efficiency of the order of 44% can be reached with the use of oxygen enrichment.

Hals, F.; Kessler, R.; Swallom, D.; Westra, L.; Zar, J.; Morgan, W.; Bozzuto, C.

1980-06-01

240

Open Cycle Coal Fired MHD Power Generation. Final Report, 21 May 1971--31 May 1975.  

National Technical Information Service (NTIS)

Research during the past 3 years on coal-fired MHD has included: critical engineering experiments and studies: (a) modeling of the total MHD system; (b) materials development; (c) coal studies (devolatilization and ash behavior); (d) MHD plasma effects; (...

1975-01-01

241

Hall Magnetohydrodynamics with Electron inertia  

NASA Astrophysics Data System (ADS)

Waves occurring in Hall Magnetohydrodynamics (HMHD) show many interesting features, such as the incompressible MHD shear Alfvén wave becomes a compressible wave while the two MHD compressible waves become incompressible, the fast wave becoming mostly electromagnetic and the slow wave becomes almost a fluid-dynamical wave. These features have been supported by numerical simulations by Dastgeer et al. Recent numerical simulations on solar wind turbulence show some interesting features for the power spectra, like the predominance of Whistler cascades in the range kd_e < 1 , where k is the wave number and de is the electron inertial length. In this work, we first consider the linear dispersion relation for a complete two-fluid plasma with the electron mass me not equal to zero. We analyze the different branches of the dispersion relation for different ranges of kd_e , i.e., kd_e > 1 and kde < 1, in addition to the ranges kd_i >1 and kd_i <1. The wave characteristics, which show many significant features are discussed and plotted numerically.

McKenzie, J. F.; Dasgupta, B.; Shaikh, D.

2009-12-01

242

Closed cycle MHD power generation experiments in the NASA Lewis Facility  

NASA Technical Reports Server (NTRS)

Many modifications were made in the MHD facility. These include a redesign of the MHD duct interior, addition of mixing bars, increased electrical isolation of all the high temperature components from each other and from ground, and experimentation with various cesium seed vaporization and injection techniques. With the exception of the cesium system which needs further improvement the above modifications were quite successful and resulted in improvements in generator performance. The facility was run for a total of 400 hours in the past year, with 70 hours of this operation at temperatures of 2000 K or more with hot generator walls. With the exception of replacing one cracked brick in the MHD channel no repairs were required in the high temperature loop components for the duration of these tests. Uniform Faraday and Hall voltage profiles were obtained and the Faraday open circuit voltage varied from 90 to 100 percent of the ideal uBh. The magnitudes of the measured parameters are: Faraday open circuit voltage approximately 70 V, total Faraday current approximately 20 A, Hall voltage approximately 250 V, power output approximately 300 W, and power density .036 W/cu cm.

Sovie, R. J.; Nichols, L. D.

1974-01-01

243

Methods of reducing energy consumption of the oxidant supply system for MHD/steam power plants  

NASA Technical Reports Server (NTRS)

An in-depth study was conducted to identify possible improvements to the oxidant supply system for combined cycle MHD power plants which would lead to higher thermal efficiency and reduction in the cost of electricity, COE. Results showed that the oxidant system energy consumption could be minimized when the process was designed to deliver a product O2 concentration of 70 mole percent. The study also led to the development of a new air separation process, referred to as 'liquid pumping and internal compression'. MHD system performance calculations show that the new process would permit an increase in plant thermal efficiency of 0.6 percent while allowing more favorable tradeoffs between magnetic energy and oxidant system capacity requirements.

Juhasz, A. J.

1983-01-01

244

Methods of reducing energy consumption of the oxidant supply system for MHD/steam power plants  

NASA Technical Reports Server (NTRS)

An in-depth study was conducted to identify possible improvements to the oxidant supply system for combined cycle MHD power plants which would lead to higher thermal efficiency and reduction in the cost of electricity, COE. Results showed that the oxidant system energy consumption could be minimized when the process was designed to deliver a product O2 concentration of 70 mole percent. The study also led to the development of a new air separation process, referred to as liquid pumping and internal compression. MHD system performance calculations show that the new process would permit an increase in plant thermal efficiency of 0.6 percent while allowing more favorable tradeoffs between magnetic energy and oxidant system capacity requirements.

Juhasz, A. J.

1983-01-01

245

Corrosion and arc erosion in MHD channels  

NASA Astrophysics Data System (ADS)

The objective of this task is to study the corrosion and arc erosion of magnetohydrodynamic (MHD) materials in a cooperative effort with, and to support, the MHD topping cycle program. Materials tested in the Avco Research Laboratory/Textron facility, or materials which have significant MHD importance, will be analyzed to document their physical deterioration. Conclusions shall be drawn about their wear mechanisms and lifetime in the MHD environment with respect to the following issues: sulfur corrosion, electrochemical corrosion, and arc erosion. The impact of any materials or slag conditions on the level of power output and on the level of leakage current in the MHD channel will also be noted, where appropriate. The detailed correlation and analysis of data obtained from nearly all of the tests performed since 1986 has shown that the apparent leakage current flowing through the slag on the channel walls depends upon channel operating parameters in an unexpected way. A comprehensive report of the results obtained to date and a first attempt at their interpretation has been prepared and a copy is attached. The second activity has concerned the examination of electrodes (platinum anodes/tungsten cathodes) by scanning electron microscopy and energy dispersive x ray spectroscopy of the surface degradation. Results of these examinations are reported.

Rosa, Richard J.; Pollina, Richard J.

1990-04-01

246

Parabolized Navier-Stokes Code for Computing Magneto-Hydrodynamic Flowfields  

NASA Technical Reports Server (NTRS)

This report consists of two published papers, 'Computation of Magnetohydrodynamic Flows Using an Iterative PNS Algorithm' and 'Numerical Simulation of Turbulent MHD Flows Using an Iterative PNS Algorithm'.

Mehta, Unmeel B. (Technical Monitor); Tannehill, J. C.

2003-01-01

247

Tungsten and tungsten-copper for coal-fired MHD power generation  

NASA Astrophysics Data System (ADS)

Magnetohydrodynamics (MHO) can improve the thermal efficiency and reduce levels of SOx and NO emissions of existing coal-fired power generation plants. Although the thermal and electrochemical environments for a coal-fired MHO channel challenge the materials used, platinum, tungsten, and tungsten-copper have been found to be suitable choices. Evaluations indicate these materials perform adequately as electrodes and other gas-side surfaces in the coal-fired MHO channel. Analysis of test elements has resulted in the identification of wear mechanisms. Testing of a prototypical coal-fired MHO channel incorporating these materials is under way and will be completed in 1993.

Farrar, L. C.; Shields, J. A.

1992-08-01

248

BOOK REVIEW: Nonlinear Magnetohydrodynamics  

NASA Astrophysics Data System (ADS)

Nonlinear magnetohydrodynamics by Dieter Biskamp is a thorough introduction to the physics of the most impressive non-linear phenomena that occur in conducting magnetoplasmas. The basic systems, in which non-trivial dynamic processes are observed, accompanied by changes of geometry of the magnetic field and the effects of energy transformation (magnetic energy into kinetic energy or the opposite effect in magnetic dynamos), are the plasma magnetic confinement systems for nuclear fusion and space plasmas, mainly the solar plasma. A significant number of the examples of the dynamic processes considered are taken from laboratory plasmas, for which an experimental check of the theory is possible. Therefore, though the book is intended for researchers and students interested in both laboratory, including nuclear fusion, and astrophysical plasmas, it is most probably closer to the first category of reader. In the Introduction the author notes that unlike the hydrodynamics of non-conducting fluids, where the phenomena caused by rapid fluid motions are the most interesting, for plasmas in a strong magnetic field the quasi-static configurations inside which the local dynamic processes occur are often the most important. Therefore, the reader will also find in this book rather traditional material on the theory of plasma equilibrium and stability in magnetic fields. In addition, it is notable that, as opposed to a linear theory, the non-linear theory, as a rule, cannot give quite definite explanations or predictions of phenomena, and consequently there are in the book many results obtained by consideration of numerical models with the use of supercomputers. The treatment of non-linear dynamics is preceded by Chapters 2 to 4, in which the basics of MHD theory are presented with an emphasis on the role of integral invariants of the magnetic helicity type, a derivation of the reduced MHD equations is given, together with examples of the exact solutions of the equilibrium equations of a plasma in a magnetic field (which will be used further in models of dynamic processes), approaches to the description of three dimensional (3-D) equilibrium are briefly discussed, and the basis of the theory of linear instabilities and the basic types of MHD instabilities, with account taken of ideal resistive modes, are considered. The value of the material of these chapters is that here in a brief form the results of numerous researches in this area are presented, and frequently with a fresh point of view of old results. Chapters 5 to 10 are devoted to the subject of the book, non-linear magnetohydrodynamics. In the introduction to Chapter 5 the author pays attention to the fact that long standing doubts about the feasibility of magnetic thermonuclear reactors because of inevitable instabilities of non-uniform plasmas have been overcome in the last two decades: the plasma in tokamaks is rather well confined, despite the presence of some instabilities. The latter, as a rule, result only in the redistribution of current and plasma pressure profiles and some increase of transport, but can also lead to extremely undesirable effects. In this connection in Chapter 5 the attention of the reader is directed to the physics of the most important plasma instabilities in tokamaks. Models of the development of external and internal kink modes in tokamaks are considered, including the `vacuum bubble' model in shearless plasmas, the evolution of the resistive tearing mode together with saturation of the magnetic islands arising at a tearing instability. The rather long Chapter 6 is devoted to the fundamentals of the magnetic hydrodynamic dissipative process in the magnetic field line reconnection. This process of rapid dissipation of the energy of a magnetic field, having in the simplest case different directions in two adjacent volumes of plasma, underlies the theory of the phenomenon of powerful flares in the solar chromosphere, resulting in the well-known `magnetic storms' on the earth, and the theory of rather dangerous disruptive instabilities in tokamaks. Aft

Shafranov, V.

1998-08-01

249

Multidimensional MHD Algorithms in Athena  

NASA Astrophysics Data System (ADS)

We briefly outline our efforts at constructing multidimensional Godunov algorithms for solving the ideal magnetohydrodynamics equations. These algorithms use an extension of the Piecewise Parabolic Method (PPM) for constructing interface states which includes MHD source terms for both stability and accuracy of the method. We present a physically intuitive description of the MHD source terms used for calculating the PPM interface states for the three-dimensional MHD system and show that this is a generalization of the method used for our two-dimensional integration algorithm. We also present the solutions for two MHD problems as an illustration of the properties of the method.

Gardiner, T. A.; Stone, J. M.

2006-12-01

250

Definition of the development program for a MHD advanced power train. Task I, Final report  

SciTech Connect

These recommended plant arrangements are based on the results of the economic and performance analyses combined with other qualitative factors determined to be important to utilities including the following: maintainability, constructability, sizeability, risk factor, sensitivity to cost of fuel escalation, and previous test experience. For the 200 and 500 MWe plants relatively short, supersonic channels have been recommended for the MHD power train. Although longer, subsonic channels are projected to offer slightly better performance the supersonic channels offer reduced capital costs due to the fact that a less costly 4.5 Tesla magnet has been assumed for the cases of supersonic operation. The lower capital costs lead to essentially equivalent COE's in comparing the economics of supersonic versus subsonic operation. An important factor in recommending supersonic channels is the perceived risk reduction associated with the utilization of a smaller 4.5 Tesla magnet for early plants. Risks are further reduced with the availability of substantial supersonic channel test experience. Given the continued development of MHD components over the extended time period when 1000 MWe MHD/steam plants will be constructed, risk was not a primary factor and the selected configuration for this size utilizes a long length, subsonic channel to enhance performance.

Not Available

1983-11-01

251

Magnetohydrodynamic viscous flow over a nonlinearly moving surface: Closed-form solutions  

NASA Astrophysics Data System (ADS)

In this paper, the magnetohydrodynamic (MHD) flow over a nonlinearly (power-law velocity) moving surface is investigated analytically and solutions are presented for a few special conditions. The solutions are obtained in closed forms with hyperbolic functions. The effects of the magnetic, the wall moving, and the mass transpiration parameters are discussed. These solutions are important to show the flow physics as well as to be used as bench mark problems for numerical validation and development of new solution schemes.

Fang, Tiegang

2014-05-01

252

Prospects for energy recovery from plastic waste gasifiers by means of MHD topping cycle  

SciTech Connect

In this paper the authors present a feasibility study of a combined MagnetoHydroDynamic (MHD) and steam turbine plant in which the working gas is made of burnt plastic waste. The possibility of MHD retrofit of existing plant, especially fed by fossil fuel, is well known, and has been studied both for its economical and environmental benefits. The environmental impact and the elimination of pollution agents has become a prime necessity in waste digestion. Furthermore, plants in which the production of electrical power by means of burnt gases produced in the digestion process have been designed and built. In this field an MHD integration plant could be very attractive. This feasibility study has been developed by simulating an ideal plant with a plastic incinerator, an MHD device and conventional steam turbines. As a result, the simulations have indicated economic and environmental advantages with notable efficiency improvements in the generation of electrical power.

Geri, A.; Verdone, N.; Salvini, A.

1999-12-01

253

Kinetics of the desulfurization of an exhausted ionizing additive in a MHD electric power plant  

NASA Astrophysics Data System (ADS)

The removal of sulfur oxides from exhaust gases is an acute problem in the operation of open-cycle MHD power plants. This paper proposes a method for calculating the rate of reaction between potassium sulfate and hydrogen at temperatures of 1033-1073 K. The method is based on the assumption that the process occurs in two stages: activated adsorption and a reaction in the adsorbed phase. An experimental desulfurization unit operating on these principles is described, and results of calculations are compared with experimental data.

Vizel, Ia. M.; Ibragimov, R. A.; Mostinskii, I. L.

1980-07-01

254

Kinetics of the desulfurization of an exhausted ionizing additive in a MHD electric power plant  

NASA Astrophysics Data System (ADS)

The removal of sulfur oxides from exhaust gases is an acute problem in the operation of open-cycle MHD power plants. This paper proposes a method for calculating the rate of reaction between potassium sulfate and hydrogen at temperatures of 1033-1073 K. The method is based on the assumption that the process occurs in two stages: activated adsorption and a reaction in the adsorbed phase. An experimental desulfurization unit operating on these principles is described, and results of calculations are compared with experimental data.

Vizel, Ia. M.; Ibragimov, R. A.; Mostinskii, I. L.

1981-01-01

255

Diagnostic development and support of MHD test facilities  

SciTech Connect

The Diagnostic Instrumentation and Analysis Laboratory (DIAL) at Mississippi State University (MSU) is developing diagnostic instruments for Magnetohydrodynamics (MHD) power train data acquisition and for support of MHD component development test facilities. Microprocessor-controlled optical instruments, initially developed for Heat Recovery/Seed Recovery support, are being refined, and new systems to measure temperatures and gas-seed-slag stream characteristics are being developed. To further data acquisition and analysis capabilities, the diagnostic systems are being interfaced with DIAL's computers. Technical support for the diagnostic needs of the national MHD research effort is being provided. DIAL personnel will also cooperate with government agencies and private industries to improve the transformation of research and development results into processes, products and services applicable to their needs. 9 figs., 1 tab.

Not Available

1990-01-01

256

Supersonic MHD generator system  

SciTech Connect

An improved MHD electrical power generating system of the type having a MHD topping cycle and a steam generating bottoming cycle is disclosed. The system typically includes a combustion system, a conventional MHD generator and a first diffuser radiant boiler. The improvement comprises a first supersonic MHD generator and ramjet engine configuration operatively connected in series with each other and with the conventional MHD generator. The first supersonic MHD generator and ramjet engine configuration increase the power output and improve the operating efficiency of the electrical generating system. A diffuser system is also disclosed which is in fluid communication with the supersonic MHD generator and the ramjet engine for collecting bypass plasma gas to be used for heating a second radiant boiler adapted for powering a steam turbine generator.

Rahman, M.A.

1983-11-29

257

Energy and Cross-helicity cascades in driven magnetohydrodynamic turbulence  

NASA Astrophysics Data System (ADS)

Magnetohydrodynamic (MHD) turbulence has been invoked to explain the observed power law scaling of the energy spectrum of fluctuations in the solar wind. Observations have also shown that turbulence consists of Alfv'enic fluctuations that predominantly propagate away from the sun, indicating that the turbulence possesses cross-helicity, one of three MHD ideal invariants that cascades from large to small scales in the turbulent state. Moreover, there have been recent evidence from theory and numerical simulations that cross helicity plays a more fundamental role in determining the structure of the spectrum of magnetohydrodynamic turbulence, even when no overall cross-helicity is present. In order to elucidate the role of cross-helicity in the turbulence, we perform high resolution numerical simulations of MHD turbulence with and without cross-helicity. Based on our results, we propose that in the imbalanced case the Elsasser energy spectra have different amplitudes, nevertheless, their scaling is the same and consistent with the Iroshnikov-Kraichnan scaling, also observed in the balanced case.

Perez, Jean C.; Boldyrev, Stanislav

2009-05-01

258

Plasma relaxation and topological aspects in Hall magnetohydrodynamics  

SciTech Connect

Parker's formulation of isotopological plasma relaxation process in magnetohydrodynamics (MHD) is extended to Hall MHD. The torsion coefficient {alpha} in the Hall MHD Beltrami condition turns out now to be proportional to the potential vorticity. The Hall MHD Beltrami condition becomes equivalent to the potential vorticity conservation equation in two-dimensional (2D) hydrodynamics if the Hall MHD Lagrange multiplier {beta} is taken to be proportional to the potential vorticity as well. The winding pattern of the magnetic field lines in Hall MHD then appears to evolve in the same way as potential vorticity lines in 2D hydrodynamics.

Shivamoggi, B. K. [University of Central Florida, Orlando, Florida 32816-1364 (United States)

2012-07-15

259

Channel-wall limitations in the magnetohydrodynamic induction generator  

NASA Technical Reports Server (NTRS)

Discussion of magnetohydrodynamic induction generator examines the machine in detail and materials problems influencing its design. The higher upper-temperature limit of the MHD system promises to be more efficient than present turbine systems for generating electricity.

Jackson, W. D.; Pierson, E. S.

1969-01-01

260

Method for manufacturing magnetohydrodynamic electrodes  

DOEpatents

A method of manufacturing electrodes for use in a magnetohydrodynamic (MHD) generator is described comprising the steps of preparing a billet having a core of a first metal, a tubular sleeve of a second metal, and an outer sheath of an extrusile metal; evacuating the space between the parts of the assembled billet; extruding the billet; and removing the outer jacket. The extruded bar may be made into electrodes by cutting and bending to the shape required for an MHD channel frame. The method forms a bond between the first metal of the core and the second metal of the sleeve strong enough to withstand a hot and corrosive environment.

Killpatrick, D.H.; Thresh, H.R.

1980-06-24

261

Hyperbolic Divergence Cleaning for the MHD Equations  

Microsoft Academic Search

In simulations of magnetohydrodynamic (MHD) processes the violation of the divergence constraint causes severe stability problems. In this paper we develop and test a new approach to the stabilization of numerical schemes. Our technique can be easily implemented in any existing code since there is no need to modify the solver for the MHD equations. It is based on a

A. Dedner; F. Kemm; D. Kroner; C.-D. Munz; T. Schnitzer; M. Wesenberg

2002-01-01

262

Open-cycle magnetohydrodynamic power plant with CO.sub.2 recycling  

Microsoft Academic Search

A method of converting the chemical energy of fossil fuel to electrical and mechanical energy with a MHD generator. The fossil fuel is mixed with preheated oxygen and carbon dioxide and a conducting seed of potassium carbonate to form a combustive and electrically conductive mixture which is burned in a combustion chamber. The burned combustion mixture is passed through a

Gregory F

1991-01-01

263

An open-cycle magnetohydrodynamic power plant with CO sub 2 recycling  

Microsoft Academic Search

A method of converting the chemical energy of fossil fuel to electrical and mechanical energy with a MHD generator. The fossil fuel is mixed with preheated oxygen and carbon dioxide and a conducting seed of potassium carbonate to form a combustive and electrically conductive mixture which is burned in a combustion chamber. The burned combustion mixture is passed through a

1989-01-01

264

Open-cycle magnetohydrodynamic power plant with CO sub 2 recycling  

Microsoft Academic Search

This patent describes a method of converting the chemical energy of fossil fuel to electrical and mechanical energy with a MHD generator. The fossil fuel is mixed with preheated oxygen and carbon dioxide and a conducting seed of potassium carbonate to form a combustive and electrically conductive mixture which is burned in a combustion chamber. The burned combustion mixture is

1991-01-01

265

Electromagnetic pulse and the electric power network  

Microsoft Academic Search

The nuclear electromagnetic pulse (EMP) - electric power system interaction problem is defined. A description of high altitude EMP (HEMP) characteristics, source region EMP (SREMP) characteristics, and magnetohydrodynamics EMP (MHD-EMP) characteristics are presented. The results of initial calculations of EMP induced surges on electric power transmission and distribution lines are presented and compared with lightning induced surges. Potential EMP impacts

K. W. Klein; P. R. Barnes; H. W. Zaininger

1984-01-01

266

Electromagnetic Pulse and the Electric Power Network  

Microsoft Academic Search

This paper defines the nuclear electromagnetic pulse (EMP)-electric power system interaction problem. A description of high altitude EMP (HEMP) characteristics, source region EMP (SREMP) characteristics, and magnetohydrodynamics EMP (MHD-EMP) characteristics are presented. The results of initial calculations of EMP induced surges on electric power transmission and distribution lines are presented and compared with lightning induced surges. Potential EMP impacts on

Kenneth Klein; Paul Barnes; Henry Zaininger

1985-01-01

267

A self-consistent numerical magnetohydrodynamic (MHD) model of helmet streamer and flux-rope interactions: Initiation and propagation of Coronal Mass Ejections (CMEs)  

NASA Astrophysics Data System (ADS)

We present results for an investigation of the interaction of a helmet-streamer arcade and a helical flux rope under the helmet dome. These results are obtained by using a three-dimensional axisymmetric, time-dependent ideal magnetohydrodynamic (MHO) model. Because of the physical nature of the flux-rope, we investigate two types of flux ropes; (1) high-density flux rope (i.e. flux rope without cavity, [Wu et al., 1996]), and (2) low-density flux rope (i.e. flux rope with cavity [Guo and Wu 1996]). When the streamer is disrupted by the flux rope, it will evolve into a configuration resembling the typical observed loop-like Coronal Mass Ejection (CME) in both cases. The streamer-flux-rope system with cavity is easier to disrupt, and the propagation speed of the CME is faster than in the streamer-flux-rope system without cavity. Our results demonstrate that magnetic buoyancy plays an important role in disrupting the streamer.

Wu, S. T.; Guo, W. P.

268

A MAGNETOHYDRODYNAMIC MODEL OF THE M87 JET. I. SUPERLUMINAL KNOT EJECTIONS FROM HST-1 AS TRAILS OF QUAD RELATIVISTIC MHD SHOCKS  

SciTech Connect

This is the first in a series of papers that introduces a new paradigm for understanding the jet in M87: a collimated relativistic flow in which strong magnetic fields play a dominant dynamical role. Here, we focus on the flow downstream of HST-1-an essentially stationary flaring feature that ejects trails of superluminal components. We propose that these components are quad relativistic magnetohydrodynamic shock fronts (forward/reverse fast and slow modes) in a narrow jet with a helically twisted magnetic structure. And we demonstrate the properties of such shocks with simple one-dimensional numerical simulations. Quasi-periodic ejections of similar component trails may be responsible for the M87 jet substructures observed further downstream on 10{sup 2}-10{sup 3} pc scales. This new paradigm requires the assimilation of some new concepts into the astrophysical jet community, particularly the behavior of slow/fast-mode waves/shocks and of current-driven helical kink instabilities. However, the prospects of these ideas applying to a large number of other jet systems may make this worth the effort.

Nakamura, Masanori [Department of Physics and Astronomy, Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD 21218 (United States); Garofalo, David; Meier, David L., E-mail: nakamura@stsci.ed, E-mail: david.a.garofalo@jpl.nasa.go, E-mail: david.l.meier@jpl.nasa.go [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States)

2010-10-01

269

On the locality of magnetohydrodynamic turbulence scale fluxes  

SciTech Connect

The scale locality of energy fluxes for magnetohydrodynamics (MHD) is investigated numerically for stationary states of turbulence. Two types of forces are used to drive turbulence, a kinetic force that acts only on the velocity field and a kinetic-inductive force, which acts on the velocity and magnetic fields alike. The analysis is performed in spectral space, which is decomposed into a series of shells following a power law for the boundaries. The triadic transfers occurring among these shells are computed, and the fluxes and locality functions are obtained by partial summation over the relevant shells. Employing Kraichnan locality functions, values of 1/3 and 2/3 for the scaling exponents of the four MHD energy fluxes are found. These values are smaller than the value of 4/3 found for hydrodynamic turbulence. To better understand these results, an in depth analysis is performed on the total energy flux.

Teaca, Bogdan [Centre de Recherches en Physique des Plasmas, Science de Base, Ecole Polytechnique Federale de Lausanne, Station 13, Building PPB, CH-1015 Lausanne (Switzerland); Carati, Daniele [Statistical and Plasma Physics, Faculty of Sciences, Universite Libre de Bruxelles, Campus Plaine, CP 231, B-1050 Brussels (Belgium); Andrzej Domaradzki, J. [Department of Aerospace and Mechanical Engineering, University of Southern California, Los Angeles, California 90089-1191 (United States)

2011-11-15

270

Numerical measurements of the spectrum in magnetohydrodynamic turbulence  

NASA Astrophysics Data System (ADS)

We report the results of an extensive set of direct numerical simulations of forced, incompressible, magnetohydrodynamic (MHD) turbulence with a strong guide field. The aim is to resolve the controversy regarding the power-law exponent ( ? , say) of the field-perpendicular energy spectrum E(k?)?k?? . The two main theoretical predictions ?=-3/2 and ?=-5/3 have both received some support from differently designed numerical simulations. Our calculations have a resolution of 5123 mesh points, a strong guide field, and an anisotropic simulation domain and implement a broad range of large-scale forcing routines, including those previously reported in the literature. Our findings indicate that the spectrum of well-developed, strong incompressible MHD turbulence with a strong guide field is E(k?)?k?-3/2 .

Mason, Joanne; Cattaneo, Fausto; Boldyrev, Stanislav

2008-03-01

271

Study of multi-phase flow characteristics in an MHD power train  

SciTech Connect

Computer simulation was used to predict two-phase flow processes in the CDIF MHD power train system. The predictions were used to evaluate the effects of operating and design parameters on the performance of the system and a parametric evaluation provides information to enhance the performance of the system. Major components of the system under investigation are the two-stage combustor, the converging/diverging nozzle, the supersonic MHD channel, and the diffuser. Flow in each component was simulated using a computer code. Integrating the computer codes, the two-phase flow processes in the system was calculated. Recently, the computer codes were used to investigate problems of nozzle erosion and the non-uniform iron oxide coverage on the cathode wall in the channel. A limited parametric study was conducted. The results indicated that (1) among the three nozzle geometries under investigation a {number_sign}5 nozzle has the smoothest flow development in the nozzle and has the lowest droplet deposition on wall and (2) smaller particle size and lower injection velocity tend to disperse the iron oxide particles more uniformly in the nozzle.

Chang, S.L.; Lottes, S.A.; Bouillard, J.X.; Petrick, M.

1993-08-01

272

MHD control in burning plasmas MHD control in burning plasmas  

NASA Astrophysics Data System (ADS)

Fusion physics focuses on the complex behaviour of hot plasmas confined by magnetic fields with the ultimate aim to develop a fusion power plant. In the future generation of tokamaks like ITER, the power generated by the fusion reactions substantially exceeds the external input power (Pfusion}/Pin >= 10). When this occurs one speaks of a burning plasma. Twenty per cent of the generated fusion power in a burning plasma is carried by the charged alpha particles, which transfer their energy to the ambient plasma in collisions, a process called thermalization. A new phenomenon in burning plasmas is that the alpha particles, which form a minority but carry a large fraction of the plasma kinetic energy, can collectively drive certain types of magneto-hydrodynamic (MHD) modes, while they can suppress other MHD modes. Both types of MHD modes can have desirable effects on the plasma, as well as be detrimental to the plasma. For example, the so-called sawtooth instability, on the one hand, is largely responsible for the transport of the thermalized alpha particles out of the core, but, on the other hand, may result in the loss of the energetic alphas before they have fully thermalized. A further undesirable effect of the sawtooth instability is that it may trigger other MHD modes such as neoclassical tearing modes (NTMs). These NTMs, in turn, are detrimental to the plasma confinement and in some cases may even lead to disruptive termination of the plasma. At the edge of the plasma, finally, so-called edge localized modes or ELMs occur, which result in extremely high transient heat and particle loads on the plasma-facing components of a reactor. In order to balance the desired and detrimental effects of these modes, active feedback control is required. An additional complication occurs in a burning plasma as the external heating power, which is nowadays generally used for plasma control, is small compared to the heating power of the alpha particles. The scientific challenge in the field of burn control is to find the proper balance between desired and detrimental effects of the various MHD modes and to develop the methods and tools for active feedback control of MHD modes in burning plasmas. Therefore, it is necessary to understand the dynamics of the system, in this case the mutual interactions between the fast alpha particles and the MHD instabilities. Since burning plasmas do not yet exist, the relevant experimental work until ITER comes into full operation needs to be largely based on alpha-particle simulation experiments in which the alpha particles are accelerated to high energies by means of special heating techniques. The precise conditions of a burning plasma can be only partly mimicked in present tokamaks. Hence, also a detailed computational modelling effort is needed, in order to understand the impact of findings in present machines for those of the future. In 2011 two dedicated workshops were devoted to MHD control. Firstly, there was a workshop on Control of Burning Plasmas that took place from 21-25 March 2011 at the Lorentz Centre in Leiden, The Netherlands. Secondly, the 480th Wilhelm and Else Heraeus Seminar that took place from 16-18 June in Bad Honnef, Germany was devoted to Active Control of Instabilities in Hot Plasmas. This special issue presents a collection of papers that have been presented at the two workshops, along with a few papers that are the result of an open call to contribute to this special issue.

Donné, Tony; Liang, Yunfeng

2012-07-01

273

Magnetohydrodynamic ship propulsion with superconducting magnets  

Microsoft Academic Search

The feasibility of magnetohydrodynamic (MHD) ship propulsion using superconducting magnets is reviewed in light of recent advances in high-temperature superconductivity. The scaling relations for the electrical and hydraulic efficiencies of MHD pump-jets show that overall efficiencies >50% are feasible at speeds of 40 knots and higher provided that magnetic fields >5T can be maintained over volumes of the order of

D. L. Mitchell; D. U. Gubser

1988-01-01

274

Relabeling symmetries in hydrodynamics and magnetohydrodynamics  

SciTech Connect

Lagrangian symmetries and concomitant generalized Bianchi identities associated with the relabeling of fluid elements are found for hydrodynamics and magnetohydrodynamics (MHD). In hydrodynamics relabeling results in Ertel`s theorem of conservation of potential vorticity, while in MHD it yields the conservation of cross helicity. The symmetries of the reduction from Lagrangian (material) to Eulerian variables are used to construct the Casimir invariants of the Hamiltonian formalism.

Padhye, N.; Morrison, P.J.

1996-04-01

275

MHD memes  

NASA Astrophysics Data System (ADS)

The celebration of Allan Kaufman's 80th birthday was an occasion to reflect on a career that has stimulated the mutual exchange of ideas (or memes in the terminology of Richard Dawkins) between many researchers. This paper will revisit a meme Allan encountered in his early career in magnetohydrodynamics, the continuation of a magnetohydrodynamic mode through a singularity, and will also mention other problems where Allan's work has had a powerful cross-fertilizing effect in plasma physics and other areas of physics and mathematics. To resolve the continuation problem we regularize the Newcomb equation, solve it in terms of Legendre functions of imaginary argument, and define the small weak solutions of the Newcomb equation as generalized functions in the manner of Lighthill, i.e. via a limiting sequence of analytic functions that connect smoothly across the singularity.

Dewar, R. L.; Mills, R.; Hole, M. J.

2009-05-01

276

Summary and evaluation of the conceptual design study of a potential early commercial MHD power plant (CSPEC)  

SciTech Connect

The conceptual design study of a potential early commercial MHD power plant (CSPEC) is described and the results of the study are summarized. For this study, each of two contractors did a conceptual design of an approximately 1000 MWe open-cycle MHD/steam plant with oxygen enriched combustion air preheated to an intermediate temperature in a metallic heat exchanger. The contractors were close in their overall plant efficiency estimates but differed in their capital cost and cost of electricity estimates, primarily because of differences in Balance-of-Plant material, installation, contingency, and operating and maintenance cost estimates. One contractor concluded that its MHD plant design compared favorably in cost of electricity with conventional coal-fired steam plants. The other contractor is making such a comparison as part of a follow-on study. Each contractor did a preliminary investigation of part-load performance and plant availability. The results of NASA studies investigating the effect of plant size and oxidizer preheat temperature on the performance of CSPEC-type MHD plants are also described. The efficiency of a 1000 MWe plant is about three points higher than that of a 200 MWe plant. Preheating to 1600/sup 0/F gives an efficiency about one and one-half points higher than preheating to 800/sup 0/F for all plant sizes. For each plant size and preheat temperature there is an oxidizer enrichment level and MHD generator length that gives the highest plant efficiency.

Staiger, P.J.; Penko, P.F.

1982-01-01

277

Results of closed cycle MHD power generation test with a helium-cesium working fluid  

NASA Technical Reports Server (NTRS)

The cross sectional dimensions of the MHD channel in the NASA Lewis closed loop facility were reduced to 3.8 x 11.4 cm. Tests were run in this channel using a helium-cesium working fluid at stagnation pressures of 160,000 n/M2, stagnation temperatures of 2000-2060 K and an entrance Mach number of 0.36. In these tests Faraday open circuit voltages of 200 V were measured which correspond to a Faraday field of 1750 V/M. Power generation tests were run for different groups of electrode configurations and channel lengths. Hall fields up to 1450 V/M were generated. Power extraction per electrode of 183 W and power densities of 1.7 MW/M3 were obtained. A total power output of 2 kW was generated for tests with 14 electrodes. The power densities obtained in this channel represent a factor of 3 improvement over those previously reported for the M = 0.2 channel.

Sovie, R. J.

1977-01-01

278

Results of closed cycle MHD power generation tests with a helium-cesium working fluid  

NASA Technical Reports Server (NTRS)

The cross-sectional dimensions of the MHD channel in the NASA Lewis closed loop facility have been reduced to 3.8 x 11.4 cm. Tests were run in this channel using a helium-cesium working fluid at stagnation pressures of 1.6 x 10 to the 5th N/sq m, stagnation temperatures of 2000-2060 K and an entrance Mach number of 0.36. In these tests Faraday open circuit voltages of 200 V were measured which correspond to a Faraday field of 1750 V/m. Power generation tests were run for different groups of electrode configurations and channel lengths. Hall fields up to 1450 V/m were generated. Power extraction per electrode of 183 W and power densities of 1.7 MW/cu m have been obtained. A total power output of 2 kW was generated for tests with 14 electrodes. The power densities obtained in this channel represent a factor of 3 improvement over those reported for the m = 0.2 channel at the last EAM Symposium.

Sovie, R. J.

1977-01-01

279

Ideal MHD stability of a spherical tokamak power plant and a component test facility.  

SciTech Connect

We have investigated ideal MHD stability of two advanced spherical tokamak confinement concepts: the spherical tokamak power plant (STPP), a 3 GW concept fusion power plasma producing 1 GW of electric power, and the component test facility (CTF), a concept designed for in situ materials testing for ITER and beyond. Detailed stability studies for toroidal mode number n = 1, 2, 3 displacements are presented as a function of conformal wall radius R{sub w} and on-axis safety factor q{sub 0}. For the STPP marginal stability scans held the current profile fixed, but varied the total plasma current. For the CTF we have extended and parallelized earlier marginal stability scans to scan over both the plasma beta and q{sub 0} by varying the current profile to preserve the total plasma current. These confirm that both concepts are stable provided that the wall is sufficiently close and q{sub 0} sufficiently large (q{sub 0} > 2.8 for the power plant and q{sub 0} > 2.1 for the CTF). Both power plant and CTF configurations are found to be ballooning stable.

Hole, M. J.; Wilson, H. R.; Abeysuriya, R.; Larson, J. W. (CLS-CI); ( MCS); (Australian National Univ.); (Univ. of York); (Univ. of Sydney)

2010-12-01

280

Single channel double-duct liquid metal electrical generator using a magnetohydrodynamic device  

DOEpatents

A single channel double-duct liquid metal electrical generator using a magnetohydrodynamic (MHD) device. The single channel device provides useful output AC electric energy. The generator includes a two-cylinder linear-piston engine which drives liquid metal in a single channel looped around one side of the MHD device to form a double-duct contra-flowing liquid metal MHD generator. A flow conduit network and drive mechanism are provided for moving liquid metal with an oscillating flow through a static magnetic field to produce useful AC electric energy at practical voltages and currents. Variable stroke is obtained by controlling the quantity of liquid metal in the channel. High efficiency is obtained over a wide range of frequency and power output.

Haaland, Carsten M. (Dadeville, AL) [Dadeville, AL; Deeds, W. Edward (Knoxville, TN) [Knoxville, TN

1999-01-01

281

Single channel double-duct liquid metal electrical generator using a magnetohydrodynamic device  

DOEpatents

A single channel double-duct liquid metal electrical generator using a magnetohydrodynamic (MHD) device. The single channel device provides useful output AC electric energy. The generator includes a two-cylinder linear-piston engine which drives liquid metal in a single channel looped around one side of the MHD device to form a double-duct contra-flowing liquid metal MHD generator. A flow conduit network and drive mechanism are provided for moving liquid metal with an oscillating flow through a static magnetic field to produce useful AC electric energy at practical voltages and currents. Variable stroke is obtained by controlling the quantity of liquid metal in the channel. High efficiency is obtained over a wide range of frequency and power output. 5 figs.

Haaland, C.M.; Deeds, W.E.

1999-07-13

282

System study for a tens MWe size coal-fired MHD retrofit pilot power plant in China  

Microsoft Academic Search

System analysis is made in this paper of the coal-fired MHD\\/steam combined cycle pilot power plant in the size range tens\\u000a of MWe. System performance are presented of such plants with three sizes: one 12 MWe unit, two 12 MWe units and one 50 MWe\\u000a unit which are considered as retrofits to the existing Beijing No.3 Heat and Power Plant.

Ningsheng Cai; Yiqian Xu; James N. Chapman; Ciwen Sha

1993-01-01

283

System study for a tens MWe size coal-fired MHD retrofit pilot power plant in China  

NASA Astrophysics Data System (ADS)

System analysis is made in this paper of the coal-fired MHD/steam combined cycle pilot power plant in the size range tens of MWe. System performance are presented of such plants with three sizes: one 12 MWe unit, two 12 MWe units and one 50 MWe unit which are considered as retrofits to the existing Beijing No.3 Heat and Power Plant. Parametric studies are performed for the 2 × 12 MWe units and the optimum system parameters are obtained.

Cai, Ningsheng; Xu, Yiqian; Chapman, James N.; Sha, Ciwen

1993-03-01

284

Viscous and inviscid magneto-hydrodynamics equations  

Microsoft Academic Search

In this paper we study the classical problem in turbulence for the magneto-hydrodynamics (MHD) equations: whether the solutions\\u000a (u\\u000a (v),B\\u000a (v)) of the viscous MHD equations tend to the solutions (u\\u000a (0),B\\u000a (v)) of the inviscid MHD equations as the Reynolds numbersRe, Rm ? ?. As a preparation we first derive bounds for ¦|(u\\u000a (0),B\\u000a (0)(t)¦|H\\u000a m) (m ?3) in

Jiahong Wu

1997-01-01

285

Ideal Magnetohydrodynamic Stability of the NCSX  

SciTech Connect

The ideal magnetohydrodynamic (MHD) stability of the National Compact Stellarator Experiment (NCSX) is extensively analyzed using the most advanced three-dimensional MHD codes. It is shown that the NCSX is stable to finite-n MHD modes, including the vertical mode, external kink modes and ballooning modes. However, high-n external kink modes that peak near the plasma edge are found to be weakly unstable. A global calculation shows that finite-n ballooning modes are significantly more stable than the local infinite-n modes.

Fu, GuoYong [Princeton Plasma Physics Laboratory (PPPL); Isaev, Maxim Yu [Kurchatov Institute, Moscow, Russia; Ku, Long-Poe [Princeton Plasma Physics Laboratory (PPPL); Mikhailov, M [Kurchatov Institute, Moscow, Russia; Redi, M H [Princeton Plasma Physics Laboratory (PPPL); Sanchez, Raul [ORNL; Subbotin, A [Kurchatov Institute, Moscow, Russia; Hirshman, Steven Paul [ORNL; Cooper, W Anthony [CRPP/EPFL, Association Euratom-Suisse, Lausanne, Switzerland; Monticello, D. [Princeton Plasma Physics Laboratory (PPPL); Reiman, A H [Princeton Plasma Physics Laboratory (PPPL); Zarnstorff, M. C. [Princeton Plasma Physics Laboratory (PPPL)

2007-01-01

286

Evaluation of technical feasibility of closed-cycle non-equilibrium MHD power generation with direct coal firing. Final report, Task I  

SciTech Connect

Program accomplishments in a continuing effort to demonstrate the feasibility of direct coal-fired, closed-cycle MHD power generation are reported. This volume contains the following appendices: (A) user's manual for 2-dimensional MHD generator code (2DEM); (B) performance estimates for a nominal 30 MW argon segmented heater; (C) the feedwater cooled Brayton cycle; (D) application of CCMHD in an industrial cogeneration environment; (E) preliminary design for shell and tube primary heat exchanger; and (F) plant efficiency as a function of output power for open and closed cycle MHD power plants. (WHK)

Not Available

1981-11-01

287

A simulation of the IPS variations from a magnetohydrodynamical simulation  

NASA Technical Reports Server (NTRS)

Calculations of the variations of interplanetary scintillation (IPS) from a disturbance simulated by a 3-D magnetohydrodynamical (MHD) model of the solar wind are presented. The simulated maps are compared with observations and it is found that the MHD model reproduces the qualitative features of observed disturbances. The disturbance produced by the MHD simulation is found to correspond in strength with the weakest disturbance which can be reliably detected by existing single station IPS observations.

Tappin, S. J.; Dryer, M.; Han, S. M.; Wu, S. T.

1987-01-01

288

Magnetohydrodynamic flow computations in three dimensions  

SciTech Connect

A complete three-dimensional numerical simulation of steady laminar MHD incompressible flow was carried out. A mathematical model of magnetohydrodynamics in which the electric field vector is eliminated from the Maxwell equations is described. The numerical method for solving the system of governing equations is presented. 14 refs.

Lee, S.; Dulikravich, G.S. (Pennsylvania State Univ., University Park (USA))

1991-01-01

289

Chapter 5: Magnetohydrodynamic Studies in the FTU  

Microsoft Academic Search

The main magnetohydrodynamic (MHD) activities affecting the Frascati Tokamak Upgrade (FTU) high-field plasmas with limiter configuration are sawtooth relaxations and tearing modes.The period of sawtooth relaxations can be increased in FTU both by electron heating and by pellet particle deposition near the sawtooth inversion radius; both methods lead to full stabilization in proper conditions. The sawtooth period can be shortened

P. Buratti Associazione; A. Airoldi; F. Alladio; S. V. Annibaldi; A. Bruschi; S. Cirant; R. M. Coelho; F. Gandini; E. Giovannozzi; E. Lazzaro; P. Micozzi; S. Nowak; F. Porcelli; G. Ramponi; P. Smeulders; O. Tudisco

2004-01-01

290

An approximate Riemann solver for relativistic magnetohydrodynamics  

Microsoft Academic Search

A Godunov-type scheme for relativistic magnetohydrodynamic (MHD) equations is developed. We consider the Maxwell equations and dynamic equations for a gas with perfect conductivity in hyperbolic form as was suggested by van Putten. To calculate the fluxes of conservative variables through cells' interfaces we suggest an algorithm for the solution of the linearized Riemann problem. `Primitive' variables are calculated by

A. V. Koldoba; O. A. Kuznetsov; G. V. Ustyugova

2002-01-01

291

Structure of homogeneous nonhelical magnetohydrodynamic turbulence  

Microsoft Academic Search

Results are presented for three-dimensional direct numerical simulations of nonhelical magnetohydrodynamic (MHD) turbulence for both stationary isotropic and homogeneous shear flow configurations with zero mean induction and unity magnetic Prandtl number. Small scale dynamo action is observed in both flows, and stationary values for the ratio of magnetic to kinetic energy are shown to scale nearly linearly with the Taylor

R. S. Miller; F. Mashayek; V. Adumitroaie; P. Givi

1996-01-01

292

Open-cycle magnetohydrodynamic power plant with CO.sub.2 recycling  

DOEpatents

A method of converting the chemical energy of fossil fuel to electrical and mechanical energy with a MHD generator. The fossil fuel is mixed with preheated oxygen and carbon dioxide and a conducting seed of potassium carbonate to form a combustive and electrically conductive mixture which is burned in a combustion chamber. The burned combustion mixture is passed through a MHD generator to generate electrical energy. The burned combustion mixture is passed through a diffuser to restore the mixture approximately to atmospheric pressure, leaving a spent combustion mixture which is used to heat oxygen from an air separation plant and recycled carbon dioxide for combustion in a high temperature oxygen preheater and for heating water/steam for producing superheated steam. Relatively pure carbon dioxide is separated from the spent combustion mixture for further purification or for exhaust, while the remainder of the carbon dioxide is recycled from the spent combustion mixture to a carbon dioxide purification plant for removal of water and any nitrous oxides present, leaving a greater than 98% pure carbon dioxide. A portion of the greater then 98% pure carbon dioxide stream is recovered and the remainder is recycled to combine with the oxygen for preheating and combination with the fossil fuel to form a combustion mixture.

Berry, Gregory F. (Naperville, IL)

1991-01-01

293

System study of an MHD/gas turbine combined-cycle baseload power plant  

SciTech Connect

The MHD/gas turbine combined-cycle system has been designed specifically for applications where the availability of cooling water is very limited. The base case systems which were studied consisted of an MHD plant with a gas turbine bottoming plant, and required no cooling water. The gas turbine plant uses only air as its working fluid and receives its energy input from the MHD exhaust gases by means of metal tube heat exchangers. In addition to the base case systems, vapor cycle variation systems were considered which included the addition of a vapor cycle bottoming plant to improve the thermal efficiency. These systems required a small amount of cooling water. The MHD/gas turbine systems were modeled with sufficient detail, using realistic component specifications and costs, so that the thermal and economic performance of the system could be accurately determined. Three cases of MHD/gas turbine systems were studied, with Case I being similar to an MHD/steam system so that a direct comparison of the performances could be made, with Case II being representative of a second generation MHD system, and with Case III considering oxygen enrichment for early commercial applications. The systems are nominally 800 MW/sub e/ to 1000 MW/sub e/ in size. The results show that the MHD/gas turbine system has very good thermal and economic performances while requiring either little or no cooling water.

Annen, K.D.

1982-01-01

294

System study of an MHD\\/gas turbine combined-cycle baseload power plant  

Microsoft Academic Search

The MHD\\/gas turbine combined-cycle system has been designed specifically for applications where the availability of cooling water is very limited. The base case systems which were studied consisted of an MHD plant with a gas turbine bottoming plant, and required no cooling water. The gas turbine plant uses only air as its working fluid and receives its energy input from

Annen

1982-01-01

295

Magnetohydrodynamics (MHD) Engineering Test Facility (ETF) 200-MWe power plant: conceptual design engineering report (CDER). Volume IV. Supplementary engineering data  

SciTech Connect

This section of the CDER contains background data used in the development of the physical and technical design, as well as plant costs and schedules, presented in the previous sections. Included is a listing and discussion of major issues covering materials, components, systems, and techniques which could influence the final ETF design. Studies have been performed for some of the more significant issues and are presented. Also included are outlines of plans for a performance assurance program and to perform an environmental analysis for the chosen site. Detail design information for the various systems which comprise the ETF design is contained in the System Design Descriptions.

Not Available

1981-09-01

296

Magnetohydrodynamic stability comparison theorems revisited  

SciTech Connect

Magnetohydrodynamic (MHD) stability comparison theorems are presented for several different plasma models, each one corresponding to a different level of collisionality: a collisional fluid model (ideal MHD), a collisionless kinetic model (kinetic MHD), and two intermediate collisionality hybrid models (Vlasov-fluid and kinetic MHD-fluid). Of particular interest is the re-examination of the often quoted statement that ideal MHD makes the most conservative predictions with respect to stability boundaries for ideal modes. Some of the models have already been investigated in the literature and we clarify and generalize these results. Other models are essentially new and for them we derive new comparison theorems. Three main conclusions can be drawn: (1) it is crucial to distinguish between ergodic and closed field line systems; (2) in the case of ergodic systems, ideal MHD does indeed make conservative predictions compared to the other models; (3) in closed line systems undergoing perturbations that maintain the closed line symmetry this is no longer true. Specifically, when the ions are collisionless and their gyroradius is finite, as in the Vlasov-fluid model, there is no compressibility stabilization. The Vlasov-fluid model is more unstable than ideal MHD. The reason for this is related to the wave-particle resonance associated with the perpendicular precession drift motion of the particles (i.e., the ExB drift and magnetic drifts), combined with the absence of any truly toroidally trapped particles. The overall conclusion is that to determine macroscopic stability boundaries for ideal modes for any magnetic geometry using a simple conservative approach, one should analyze the ideal MHD energy principle for incompressible displacements.

Cerfon, Antoine J.; Freidberg, Jeffrey P. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, 167 Albany Street, Cambridge, Massachusetts 02139 (United States)

2011-01-15

297

Parametric study of potential early commercial MHD power plants. Task 3: Parameter variation of plant size  

NASA Technical Reports Server (NTRS)

Plants with a nominal output of 200 and 500 MWe and conforming to the same design configuration as the Task II plant were investigated. This information is intended to permit an assessment of the competitiveness of first generation MHD/steam plants with conventional steam plants over the range of 200 to 1000 MWe. The results show that net plant efficiency of the MHD plant is significantly higher than a conventional steam plant of corresponding size. The cost of electricity is also less for the MHD plant over the entire plant size range. As expected, the cost differential is higher for the larger plant and decreases with plant size. Even at the 200 MWe capacity, however, the differential in COE between the MHD plant and the conventional plant is sufficient attractive to warrant serious consideration. Escalating fuel costs will enhance the competitive position of MHD plants because they can utilize the fuel more efficiently than conventional steam plants.

Hals, F. A.

1981-01-01

298

Conceptual design of a coal-fired retrofit liquid-metal MHD power system  

SciTech Connect

The desire to develop a coal-fired energy-conversion system with the high efficiencies and moderate temperatures of two-phase-generator liquid-metal MHD (LMMHD) systems led to the open-cycle LMMHD (OC-LMMHD) concept. A liquid metal, most likely copper, that is compatible with combustion gases is used so that the combustion gas can be mixed with the liquid metal to form the two-phase mixture in the LMMHD generator, thereby eliminating the need for a primary heat exchanger. Applications where OC-LMMHD appears to be particularly attractive include central power plants larger than approx. 10 MW(e), retrofit of existing oil- or gas-fired central steam power plants to burn coal, and cogeneration systems requiring high-temperature process heat. The latter two, in particular, benefit from the clean combustion gas stream leaving the copper in the LMMHD system. To explore the technical and economic feasibility of this new LMMHD concept, a conceptual design study of the retrofit of a coal-fired OC-LMMHD topping cycle to a conventional steam plant was selected, and extensive parametric studies carried out to establish the optimum parameter ranges for the retrofit cycle. A conceptual design was developed for the plant and the components with sufficient detail that a cost estimate for the retrofit could be readily made.

Pierson, E.S.; Herman, H.; Petrick, M.

1981-01-01

299

Magnetohydrodynamics in Hydra  

NASA Astrophysics Data System (ADS)

The Magnetohydrodynamics package in the ALE radiation-hydrodynamics ICF design code Hydra is based upon a three-dimensional vector finite element method. This defines a set of spaces and differential operators that maintain the zero divergence of the magnetic field exactly. It is fully implicit in time and second order accurate in space. We discuss several improvements to the MHD package. The first addition is an anisotropic tensor based heat conduction method. The second improvement is a method for solving the magnetic diffusion equation for all of the element types resulting from point and line singularities including tetrahedral and pyramid elements. Finally a new magnetic flux advection method was implemented based on the method by A.C Robinson, et al.ootnotetextA.C. Robinson, J. H. J. Niederhaus, V. G. Weirs, E. Love, Int. J. Numer. Meth. Fluids, 65, 1438 (2011)

Koning, J. M.; Kerbel, G. D.; Marinak, M. M.

2011-11-01

300

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

301

MHD Energy Bypass Scramjet Performance with Real Gas Effects.  

National Technical Information Service (NTIS)

The theoretical performance of a scramjet propulsion system incorporating an magneto-hydro-dynamic (MHD) energy bypass scheme is calculated. The one-dimensional analysis developed earlier, in which the theoretical performance is calculated neglecting skin...

C. Park U. B. Mehta D. W. Bogdanoff

2000-01-01

302

Results from study of potential early commercial MHD power plants and from recent ETF design work. [Engineering Test Facility  

NASA Technical Reports Server (NTRS)

The study deals with different 'moderate technology' entry-level commercial MHD power plants. Two of the reference plants are based on combustion of coal with air preheated in a high-temperature regenerative air heater separately fired with a low-BTU gas produced in a gasifier integrated with the power plant. The third reference plant design is based on the use of oxygen enriched combustion air. Performance calculations show that an overall power plant efficiency of the order of 44% can be reached with the use of oxygen enrichment.

Hals, F.; Kessler, R.; Swallom, D.; Westra, L.; Zar, J.; Morgan, W.; Bozzuto, C.

1980-01-01

303

User's Manual for the UTSI MHD/steam power plant Systems Code  

SciTech Connect

This report is a User's Manual for the UTSI Systems Code for analysis of the cost/performance of combined cycle MHD steam power plants. In addition to the original code, it contains the NASA SP-273 code for chemical equilibrium calculations and PRESTO steam plant code which was originated by the General Electric Company and modified by Oak Ridge National Laboratories and NASA. This document describes the new code and its application but does not attempt to reproduce the documents describing the SP-273 and PRESTO codes. A new one-dimensional generator code is provided which was developed from other UTSI codes specifically for integration into this Systems Code. An alternative is provided so that the user can enter the required generator characteristics from an external calculation. The report describes the required inputs and outputs produced. It also describes the calculational methodology so that a potential user can modify or expand any calculation as required. New and substantially modified code is provided in the appendices, along with sample inputs and outputs.

Chapman, J.N.; Kiessling, E.H.; Altstatt, M.C.; Prather, C.D.

1985-01-01

304

MHD integrated topping cycle. Twenty-fourth quarterly technical progress report, May 1993--July 1993  

SciTech Connect

The Magnetohydrodynamics (MHD) Integrated Topping Cycle (ITC) Project represents the culmination of the proof-of-concept (POC) development stage in the U.S. Department of Energy (DOE) program to advance MHD technology to early commercial development stage utility power applications. The project is a joint effort, combining the skills of three topping cycle component developers: TRW, TDS, and Westinghouse. TRW, the prime contractor and system integrator, is responsible for the 50 thermal megawatt (50 MW) stagging coal combustion subsystem. TDS is responsible for the MHD channel subsystem (nozzle, channel, diffuser, and power conditioning circuits), and Westinghouse is responsible for the current consolidation subsystem. The ITC Project will advance the state-of-the-art in MHD power systems with the design, construction, and integrated testing of 50 MW, power train components which are prototypical of the equipment that will be used in an early commercial scale MHD utility retrofit. Long duration testing of the integrated power train at the Component Development and Integration Facility (CDIF) in Butte, Montana will be performed, so that by the early 1990`s, an engineering data base on the reliability, availability, maintainability and performance of the system will be available to allow scaleup of the prototypical designs to the next development level.

NONE

1993-11-01

305

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

306

MHD plant turn down considerations  

SciTech Connect

The topic of part load operation of the MHD power plant is assessed. Current and future planned MHD research is reviewed in terms of addressing topping and bottoming cycle integration needs. The response of the MHD generator to turn up and down scenarios is reviewed. The concept of turning the MHD power to met changes in plant load is discussed. The need for new ideas and focused research to study MHD plant integration and problems of plant turn down and up is cited. 7 refs., 5 figs., 1 tab.

Lineberry, J.T.; Chapman, J.N.

1991-01-01

307

Magnetohydrodynamic and hybrid simulations of broadband fluctuations near interplanetary shocks  

SciTech Connect

We present results of a theoretical study of evolution of a spectrum of finite amplitude right-hand elliptically polarized magnetohydrodynamic (MHD) waves. The analysis includes use of one-and-a-half-dimensional solutions of the equations that describe compressible MHD together with one-and-a-half-dimensional hybrid simulation of the phenomenon. The motivation of the study is to understand the origin and properties of finite amplitude waves often observed in the vicinity of collisionless shocks in the heliosphere. The solutions of the MHD equations are compared with both the results of the hybrid simulations and observations previously reported by Vinas et al. in the vicinity of a quasi-parallel interplanetary shock. The initial conditions of the MHD solutions were constructed to model the observed spectrum of magnetic and velocity fluctuations; plasma parameters were also chosen to replicate the observed parameters. For the typical parameters of {beta} = 0.5, {sigma}B/B{sub 0} = 0.25 and a spectrum of parallel propagating, circularly polarized dispersive waves, initially the density and magnetic energy density correlations grow due to the (nonlinear) ponderomotive effect. The spectral features below the ion cyclotron frequency are established quickly on the Alfvenic timescale but then persist and match closely the observed fluctuations. The parametric decay instabilities that subsequently appear further enhance the density fluctuations and produce a high-frequency magnetic power spectrum consistent with the spacecraft observation. The MHD and hybrid simulations extend the previous picture of wave generation by a beam-driven ion cyclotron instability to the fully nonlinear stage. 64 refs., 24 figs.

Agim, Y.Z.; Vinas, A.F.; Goldstein, M.L. [NASA Goddard Space Flight Center, Greenbelt, MD (United States)] [NASA Goddard Space Flight Center, Greenbelt, MD (United States)

1995-09-01

308

Disk MHD generator study  

SciTech Connect

A parametric study of coal-fired MHD/steam power plants with disk-shaped MHD generators was performed, in order to investigate the potential of such systems. Both open-cycle and closed-cycle MHD power trains were investigated. For the open-cycle disk power plants, system configurations of three basic types were evaluated: one type with directly-fired high temperature regenerative air heaters; a second type with separate gasifier-fired high temperature regenerative air heaters; and a third type without a regenerative air heater but with oxygen enrichment of the MHD combustor oxidant. The closed-cycle disk power plant systems analyses investigated the performance of argon-driven disk generator systems with direct coal combustor firing of the argon regenerators. Open-cycle disk generator performance calculated in the study were found to lie in the range of performances reported by similar studies of linear MHD systems. The calculated performances of the closed-cycle disk generator systems were also found to be comparable to the calculated performances for similarly-sized linear generator systems. Costs for disk-related components were determined to be from one-half to three-quarters of the major component costs for linear MHD power systems. Closed-cycle disk component costs were also shown to have the potential for being significantly lower than those of comparable linear MHD systems.

Retallick, F.D.

1980-10-01

309

Diagnostic development and support of MHD test facilities. Technical progress report, January--March 1991  

SciTech Connect

The Diagnostic Instrumentation and Analysis Laboratory (DIAL) at Mississippi State University (MSU) is developing diagnostic instruments for magnetohydrodynamic (MHD) power train data acquisition and for support of MHD component development test facilities. Microprocessor-controlled optical instruments, initially developed for Heat Recovery/Seed Recovery (HRSR) support, are being refined, and new systems to measure temperatures and gas-seed-slag stream characteristics are being developed. To further data acquisition and analysis capabilities, the diagnostic systems are being interfaced with DIAL`S computers. Technical support for the diagnostic needs of the national MHD research effort is being provided. DIAL personnel also cooperate with government agencies and private industries to improve the transformation of research and development results into processes, products and services applicable to their needs.

Shepard, W.S.; Cook, R.L.

1991-12-31

310

Diagnostic development and support of MHD Test Facilities. Technical progress report, October 1991--December 1991  

SciTech Connect

The Diagnostic Instrumentation and Analysis Laboratory (DIAL) at Mississippi State University (MSU) is developing diagnostic instruments for magnetohydrodynamic (MHD) power train data acquisition and for support of MHD component development test facilities. Microprocessor-controlled optical instruments, initially developed for Heat Recovery/Seed Recovery (HRSR) support, are being refined, and new systems to measure temperatures and gas-seed-slag stream characteristics are being developed. To further data acquisition and analysis capabilities, the diagnostic systems are being interfaced with DIAL`s computers. Technical support for the diagnostic needs of the national MHD research effort is being provided. DIAL personnel also cooperate with government agencies and private industries to improve the transformation of research and development results into processes, products and services applicable to their needs.

Not Available

1994-07-01

311

Methods of reducing energy consumption of the oxidant-supply system for MHD/steam power plants  

SciTech Connect

An in-depth study was conducted to identify possible improvements to the oxidant supply system for combined cycle MHD power plants which would lead to higher thermal efficiency and reduction in the cost of electricity, COE. Results showed that the oxidant system energy consumption could be minimized when the process was designed to deliver a product O/sub 2/ concentration of 70 mole percent. The study also led to the development of a new air separation process, referred to as liquid pumping and internal compression. MHD system performance calculations show that the new process would permit an increase in plant thermal efficiency of 0.6% while allowing more favorable tradeoffs between magnetic energy and oxidant system capacity requirements.

Juhasz, A.J.

1983-01-01

312

Status report on MHD generator materials  

SciTech Connect

The development of materials for the MHD generator has been cited as a major technical obstacle in the development of commercial coal-fired MHD electrical power generation. Serious effort has been in progress to develop and test coal fired MHD electrodes and materials. MHD generator design and operation will be reviewed. 12 refs.

Rossing, B.R.; Cadoff, L.H.; Sadler, J.W.

1981-01-01

313

Magnetohydrodynamic Augmented Propulsion Experiment  

NASA Technical Reports Server (NTRS)

Over the past several years, efforts have been under way to design and develop an operationally flexible research facility for investigating the use of cross-field MHD accelerators as a potential thrust augmentation device for thermal propulsion systems. The baseline configuration for this high-power experimental facility utilizes a 1.5-MWe multi-gas arc-heater as a thermal driver for a 2-MWe MHD accelerator, which resides in a large-bore 2-tesla electromagnet. A preliminary design study using NaK seeded nitrogen as the working fluid led to an externally diagonalized segmented MHD channel configuration based on an expendable heat-sink design concept. The current status report includes a review of engineering/design work and performance optimization analyses and summarizes component hardware fabrication and development efforts, preliminary testing results, and recent progress toward full-up assembly and testing

Litchford, Ron J.

2008-01-01

314

Relativistic Magnetohydrodynamics  

NASA Astrophysics Data System (ADS)

Many, yet unresolved, questions in astrophysics are associated to the presence of electromagnetic fields. These include problems of solar magnetohydrodynamics, where a significant amount of observational data is available but also relativistic systems involving the launch of jets from ?-ray bursts. Motivated by these phenomena, we study a series of problems of magnetohydrodynamics. Our task is to study systems where analytical solutions are possible so that we obtain an understanding of their physical behaviour. For this purpose, we study separable solution of force-free magnetic fields and we then apply them in systems of arcade topology. This problem is motivated by the arcade structures observed on the surface of the Sun before coronal mass ejections. We assume a magnetic arcade, emerging from the surface of a spherical conductor where the magnetic field is radially self-similar. Then, because of differential rotation on the surface of the conductor the field lines are twisted and energy is injected in the system. Assuming force-free magnetic fields the system reacts in two ways, a toroidal component is introduced and the poloidal flux expands. No matter how slow the rate of differential rotation is, the predicted expansion velocity becomes very rapid at late stages. This is the limitation of the non-relativistic magnetohydrodynamics approximation. The rest of this thesis is about problems of relativistic magnetohydrodynamics. We present the analogue of force-free magnetic fields for systems of spherical geometry, first derived by Prendergast (2005) and we expand it to systems of cylindrical geometry. We derive analytical and semi-analytical solutions of electromagnetic fields emerging from a central explosion in vacuum and in the presence of a co-expanding fluid. The mathematical description of this problem leads to a set of non-linear partial differential equations. As it is impossible to find general solutions for this set of equations, we assume self-similar solutions. We discuss applications of these explosions to ?-ray bursts.

Gourgouliatos, K. N.

2009-03-01

315

Magneto-hydrodynamics simulation study of deflagration mode in co-axial plasma accelerators  

NASA Astrophysics Data System (ADS)

Experimental studies by Poehlmann et al. [Phys. Plasmas 17(12), 123508 (2010)] on a coaxial electrode magnetohydrodynamic (MHD) plasma accelerator have revealed two modes of operation. A deflagration or stationary mode is observed for lower power settings, while higher input power leads to a detonation or snowplow mode. A numerical modeling study of a coaxial plasma accelerator using the non-ideal MHD equations is presented. The effect of plasma conductivity on the axial distribution of radial current is studied and found to agree well with experiments. Lower conductivities lead to the formation of a high current density, stationary region close to the inlet/breech, which is a characteristic of the deflagration mode, while a propagating current sheet like feature is observed at higher conductivities, similar to the detonation mode. Results confirm that plasma resistivity, which determines magnetic field diffusion effects, is fundamentally responsible for the two modes.

Sitaraman, Hariswaran; Raja, Laxminarayan L.

2014-01-01

316

Hall magnetohydrodynamic ballooning instability in the magnetotail  

NASA Astrophysics Data System (ADS)

The ballooning stability of the magnetotail is considered within the framework of Hall magnetohydrodynamics (MHD). In particular, the extent to which Hall MHD effects modify ideal MHD ballooning modes is explored extensively. It is shown that Hall MHD effects primarily enter the stability analysis through changes introduced in the plasma compressibility. Hence, the incompressible ideal MHD modes are not affected, while the compressible ideal MHD modes are altered both quantitatively and qualitatively. In addition to modifying the growth rate of the compressible ideal MHD mode, Hall effects also introduce a new instability, called the entropy interchange instability, which is a variant of the ion temperature gradient instability, when the gradient ratio ??d ln Ti/d ln ? of the configuration becomes greater than 2/3, where Ti is the ion temperature and ? is the plasma density. The theory is applied to two types of magnetotail configurations-analytic equilibria developed by Voigt [in Solar Wind-Magnetosphere Coupling, edited by Y. Kamide and J. A. Slavin (Terra Scientific, Tokyo, 1986), pp. 233-273], and more realistic magnetotail configurations containing thin current sheets obtained from Hall MHD simulations of substorm dynamics by Ma and Bhattacharjee [Geophys. Res. Lett. 25, 3277 (1998)].

Zhu, P.; Bhattacharjee, A.; Ma, Z. W.

2003-01-01

317

MHD simple waves and the divergence wave  

SciTech Connect

In this paper we investigate magnetohydrodynamic (MHD) simple divergence waves in MHD, for models in which nablacentre dotBnot =0. These models are related to the eight wave Riemann solvers in numerical MHD, in which the eighth wave is the divergence wave associated with nablacentre dotBnot =0. For simple wave solutions, all physical variables (the gas density, pressure, fluid velocity, entropy, and magnetic field induction in the MHD case) depend on a single phase function phi. We consider the form of the MHD equations used by both Powell et al. and Janhunen. It is shown that the Janhunen version of the equations possesses fully nonlinear, exact simple wave solutions for the divergence wave, but no physically meaningful simple divergence wave solution exists for the Powell et al. system. We suggest that the 1D simple, divergence wave solution for the Janhunen system, may be useful for the testing and validation of numerical MHD codes.

Webb, G. M. [Center for Space Plasma and Aeronomic Research, University of Alabama in Huntsville, Huntsville, AL 35805 (United States); Pogorelov, N. V.; Zank, G. P. [Department of Physics, The University of Alabama in Huntsville, Huntsville, AL 35899 (United States); Center for Space Plasma and Aeronomic Research, University of Alabama in Huntsville, Huntsville, AL 35805 (United States)

2010-03-25

318

Nonlinear compressible magnetohydrodynamic flows modeling of a process ICP torch  

NASA Astrophysics Data System (ADS)

Magnetohydrodynamics (MHD) describes the physical behavior of inductively coupled plasma (ICP). The goal of this paper is to provide a physical understanding of a process ICP torch using a resistive MHD model. This includes a basic description and derivation of the fluid model. Inductive plasma is treated as a continuous, conducting fluid that satisfies the classical laws of motion and thermodynamics. This model combines fluid equations, similar to those used in fluid dynamics, with Maxwell's equations. Steady fluid flow and temperature equations are simultaneously solved (direct method) using a finite elements method (FEM). The electromagnetic field equations are formulated in terms of potential vector with applied voltage source, so this model is physically more consistent, a more accurate and a faster simulation. The governing resistive MHD equations for an inductive plasma flow under local thermodynamic equilibrium (LTE) and laminar flow are presented, with appropriate boundary conditions. The model enabled to obtain the electromagnetic fields, temperature and flow velocity distributions also allows the determination of the electric parameters such as impedance of the plasma torch, total power, eddy losses, etc.

Ikhlef, N.; Hacib, T.; Leroy, O.; Mékiddèche, M. R.

2012-04-01

319

Magnetohydrodynamic Augmented Propulsion Experiment: I. Performance Analysis and Design  

NASA Technical Reports Server (NTRS)

The performance of conventional thermal propulsion systems is fundamentally constrained by the specific energy limitations associated with chemical fuels and the thermal limits of available materials. Electromagnetic thrust augmentation represents one intriguing possibility for improving the fuel composition of thermal propulsion systems, thereby increasing overall specific energy characteristics; however, realization of such a system requires an extremely high-energy-density electrical power source as well as an efficient plasma acceleration device. This Technical Publication describes the development of an experimental research facility for investigating the use of cross-field magnetohydrodynamic (MHD) accelerators as a possible thrust augmentation device for thermal propulsion systems. In this experiment,a 1.5-MW(sub e) Aerotherm arc heater is used to drive a 2-MW(sub e) MHD accelerator. The heatsink MHD accelerator is configured as an externally diagonalized, segmented channel, which is inserted into a large-bore, 2-T electromagnet. The performance analysis and engineering design of the flow path are described as well as the parameter measurements and flow diagnostics planned for the initial series of test runs.

Litchford, R. J.; Cole, J. W.; Lineberry, J. T.; Chapman, J. N.; Schmidt, H. J.; Lineberry, C. W.

2003-01-01

320

Chapter 3: MHD stability, operational limits and disruptions  

NASA Astrophysics Data System (ADS)

The present physics understandings of magnetohydrodynamic (MHD) stability of tokamak plasmas, the threshold conditions for onset of MHD instability, and the resulting operational limits on attainable plasma pressure (beta limit) and density (density limit), and the consequences of plasma disruption and disruption related effects are reviewed and assessed in the context of their application to a future DT burning reactor prototype tokamak experiment such as ITER. The principal considerations covered within the MHD stability and beta limit assessments are (i) magnetostatic equilibrium, ideal MHD stability and the resulting ideal MHD beta limit; (ii) sawtooth oscillations and the coupling of sawtooth activity to other types of MHD instability; (iii) neoclassical island resistive tearing modes and the corresponding limits on beta and energy confinement; (iv) wall stabilization of ideal MHD instabilities and resistive wall instabilities; (v) mode locking effects of non-axisymmetric error fields; (vi) edge localized MHD instabilities (ELMs, etc.); and (vii) MHD instabilities and beta/pressure gradient limits in plasmas with actively modified current and magnetic shear profiles. The principal considerations covered within the density limit assessments are (i) empirical density limits; (ii) edge power balance/radiative density limits in ohmic and L-mode plasmas; and (iii) edge parameter related density limits in H-mode plasmas. The principal considerations covered in the disruption assessments are (i) disruption causes, frequency and MHD instability onset; (ii) disruption thermal and current quench characteristics; (iii) vertical instabilities (VDEs), both before and after disruption, and plasma and in-vessel halo currents; (iv) after disruption runaway electron formation, confinement and loss; (v) fast plasma shutdown (rapid externally initiated dissipation of plasma thermal and magnetic energies); (vi) means for disruption avoidance and disruption effect mitigation; and (vii) `integrated' modelling of disruptions and fast shutdown and of the ensuing effects. In each instance, the presentation within a given topical area progresses from a summary of present experimental and theoretical understanding to how this understanding projects or extrapolates to an ITER class reactor regime tokamak. Examples of extrapolations to the specific ITER design concept developed during the course of the ITER EDA are given, and assessments of the degree of adequacy of present understanding are also provided. In areas where present understanding is identified to be less than fully adequate, areas in which continuing or new research is needed are identified.

ITER Physics Expert Group on Disruptions, Control, Plasma and MHD ITER Physics Basis Editors

1999-12-01

321

Micromachined magnetohydrodynamic actuators and sensors  

DOEpatents

A magnetohydrodynamic (MHD) micropump and microsensor which utilizes micromachining to integrate the electrodes with microchannels and includes a magnet for producing magnetic fields perpendicular to both the electrical current direction and the fluid flow direction. The magnet can also be micromachined and integrated with the micropump using existing technology. The MHD micropump, for example, can generate continuous, reversible flow, with readily controllable flow rates. The flow can be reversed by either reversing the electrical current flow or reversing the magnetic field. By mismatching the electrodes, a swirling vortex flow can be generated for potential mixing applications. No moving parts are necessary and the dead volume is minimal. The micropumps can be placed at any position in a fluidic circuit and a combination of micropumps can generate fluidic plugs and valves.

Lee, Abraham P. (Walnut Creek, CA); Lemoff, Asuncion V. (Union City, CA)

2000-01-01

322

Proposal for a high efficiency power generation system with CO2 recovery by oxygen-coal-fired MHD-steam combined cycle  

Microsoft Academic Search

(1) Oxygen-fired MHD-steam combined cycle can achieve 46% of cycle efficiency even when CO2 is recovered from exhaust gas, which is very high compared with 30% of coventional power systems with CO2 recovery. (2) Advanced MHD cycle without CO2 recovery achieves very high efficiency more than 60%, if high temperature air heater and wall temperature can be realized.

Motoo Ishikawa; Juro Umoto

1995-01-01

323

Extended Magnetohydrodynamic Simulations of the Helicity Injected Torus (HIT-SI) Spheromak Experiment with the NIMROD Code  

NASA Astrophysics Data System (ADS)

A comparative study of 3-D pressureless resistive (single-fluid) magnetohydrodynamic (rMHD) and 3-D pressureless two-fluid magnetohydrodynamic (2fl-MHD) models of the Helicity Injected Torus experiment (HIT-SI) is presented. HIT-SI is a spheromak current-drive experiment that uses two geometrically asymmetric helicity injectors to generate and sustain toroidal plasmas. The goal of the experiment is to demonstrate that steady inductive helicity injection (SIHI) is a viable method for driving and sustaining a magnetized plasma for the eventual purpose of electricity production with magnetic fusion power. The experiment has achieved sustainment of nearly 100 kA of plasma current for ˜1~ms. Fusion power plants are expected to sustain a burning plasma for many minutes to hours with more than 10~MA of plasma current. The purpose of project is to determine the validity of the single-fluid and two-fluid MHD models of HIT-SI. The comparable size of the collisionless ion skin depth to the diameter of the injectors and resistive skin depth predicates the importance of two-fluid effects. The simulations are run with NIMROD (non-ideal magnetohydrodynamics code with rotation-open discussion), an initial-value, 3-D extended MHD code. A constant and uniform plasma density and temperature are assumed. The helicity injectors are modeled as oscillating normal magnetic and parallel electric field boundary conditions. The simulations use parameters that closely match those of the experiment. The simulation output is compared to the formation time, plasma current, and internal and surface magnetic fields. Results of the study indicate 2fl-MHD shows quantitative agreement with the experiment while rMHD only captures the qualitative features. The validity of each model is assessed based on how accurately it reproduces the global quantities as well as the temporal and spatial dependence of the measured magnetic fields. 2fl-MHD produces the current amplification and formation time demonstrated by HIT-SI with similar internal magnetic fields. rMHD underestimates the current amplification and exhibits a much longer formation time. Biorthogonal decomposition (BD), a powerful mathematical tool for reducing large data sets, is employed to quantify how well the simulations reproduce the measured surface magnetic fields without resorting to a probe-by-probe comparison. BD shows that 2fl-MHD captures the dominant surface magnetic structures and the temporal behavior of these features better than rMHD. In addition to the comparisons with the experiment, a detailed investigation of the rMHD and 2fl-MHD models is undertaken. lambda (mu0 J.B/B2 and current density J are used to track the prominent structures. Both lambda and J show highly dynamic, periodic patterns with significant toroidal non-uniformities, consistent with the magnetic energy spectrum. A spheromak-like object forms only in the toroidally-averaged sense. This structure never fully detaches itself from the regions directly-driven by injectors. Parameter scans are carried out to determine the dependence of current amplification on the plasma resistivity, viscosity, injector oscillation frequency, and the ratio of injector current to injector flux. An energetics analysis based on the evolution of the MHD and Hall dynamos is presented for both models. Results of this analysis indicates a large surge of energy into the spheromak mean-field (the n=0 component) by both dynamos, followed by a steady energy transfer to the n=0 predominantly by the MHD dynamo.

Akcay, Cihan

324

Real-time simulation of MHD/steam power plants by digital parallel processors  

NASA Astrophysics Data System (ADS)

Attention is given to a large FORTRAN coded program which simulates the dynamic response of the MHD/steam plant on either a SEL 32/55 or VAX 11/780 computer. The code realizes a detailed first-principle model of the plant. Quite recently, in addition to the VAX 11/780, an AD-10 has been installed for usage as a real-time simulation facility. The parallel processor AD-10 is capable of simulating the MHD/steam plant at several times real-time rates. This is desirable in order to develop rapidly a large data base of varied plant operating conditions. The combined-cycle MHD/steam plant model is discussed, taking into account a number of disadvantages. The disadvantages can be overcome with the aid of an array processor used as an adjunct to the unit processor. The conversion of some computations for real-time simulation is considered.

Johnson, R. M.; Rudberg, D. A.

325

Variational Principle of Hall Magnetohydrodynamics  

NASA Astrophysics Data System (ADS)

The Hall current, which is written by a higher order derivative term, appears as a singular perturbation term to the magnetohydrodynamics (MHD) equations. The Hall MHD system has three invariants, the energy, the magnetic (electron) and ion helicities. The ion helicity is known to be "fragile" with respect to the energy norm of the magnetic and flow fields. In a sense of selective dissipation, the ion helicity may dissipate faster than the energy. Therefore a variational principle that gives minimumenergy state under two helicities constraints becomes an ill-posed problem. On the other hand, studying stability of a shear flow system, its non-Hermitian property invalidates the standard normal-mode analysis or energy principle. The Lyapunov stability analysis (Arnold method) is an effective way to that system. In this analysis, convexity (or coerciveness) of a functional, a linear combination of invariants, plays an important role. However the functional of Hall MHD is not a convex form. It is studied how thedifficulties appear in the variational principle of minimum energy state and Lyapunov stability analysis in the Hall MHD system. In both cases the difficulties stem from the fact that the highest order derivative term in the functional is not positive definite.

Ohsaki, Shuichi

2007-06-01

326

Nonlinear subcritical magnetohydrodynamic beta limit  

SciTech Connect

Published gyrokinetic simulations have had difficulty operating beyond about half the ideal magnetohydrodynamic (MHD) critical beta limit with stationary and low transport levels in some well-established reference cases. Here it is demonstrated that this limitation is unlikely due to numerical instability, but rather appears to be a nonlinear subcritical MHD beta limit[R. E. Waltz, Phys. Rev. Lett. 55, 1098 (1985)] induced by the locally enhanced pressure gradients from the diamagnetic component of the nonlinearly driven (zero frequency) zonal flows. Strong evidence that the zonal flow corrugated pressure gradient profiles can act as a MHD-like beta limit unstable secondary equilibrium is provided. It is shown that the addition of sufficient ExB shear or operation closer to drift wave instability threshold, thereby reducing the high-n drift wave turbulence nonlinear pumping of the zonal flows, can allow the normal high-n ideal MHD beta limit to be reached with low transport levels. Example gyrokinetic simulations of experimental discharges are provided: one near the high-n beta limit reasonably matches the low transport levels needed when the high experimental level of ExB shear is applied; a second experimental example at moderately high beta appears to be limited by the subcritical beta.

Waltz, R. E. [General Atomics, P.O. Box 85608, San Diego, California 92186-5608 (United States)

2010-07-15

327

Application of a bandpower correlation method to the statistical analysis of MHD bursts in quiescent Wendelstein-7 AS stellarator plasmas  

NASA Astrophysics Data System (ADS)

This paper presents the analysis of Mirnov coil data from pure electron-cyclotron resonance heated Wendelstein-7 AS discharges with transient magnetohydrodynamical (MHD) mode activity in otherwise MHD inactive plasmas. Amplitude modulations were found on the 100 µs time scale, expected to originate from transient changes of the plasma pressure profile by anomalous transport events. The analysis was done using our custom-developed bandpower correlation method, which combines short-time Fourier transform for the decomposition of the signal with a correlation analysis to quantitatively characterize the statistical connection between the modulations in the power of different MHD modes. The effect of a confinement transition (near a rational rotational transform) on the correlation between the power modulations of different frequency modes has been studied. As high as 50% correlation was found between different frequencies in 'bad confinement' shots with enhanced transient transport, while for 'good confinement' shots no significant correlation was observed.

Pokol, G.; Por, G.; Zoletnik, S.; W7-AS Team

2007-09-01

328

Multiscaling in Hall-Magnetohydrodynamic Turbulence: Insights from a Shell Model  

NASA Astrophysics Data System (ADS)

We show that a shell-model version of the three-dimensional Hall-magnetohydrodynamic (3D Hall-MHD) equations provides a natural theoretical model for investigating the multiscaling behaviors of velocity and magnetic structure functions. We carry out extensive numerical studies of this shell model, obtain the scaling exponents for its structure functions, in both the low-k and high-k power-law ranges of three-dimensional Hall-magnetohydrodynamic, and find that the extended-self-similarity procedure is helpful in extracting the multiscaling nature of structure functions in the high-k regime, which otherwise appears to display simple scaling. Our results shed light on intriguing solar-wind measurements.

Banerjee, Debarghya; Ray, Samriddhi Sankar; Sahoo, Ganapati; Pandit, Rahul

2013-10-01

329

Helical shell models for MHD  

Microsoft Academic Search

A shell model for magnetohydrodynamics (MHD) is derived directly from the dynamical system driving the evolution of three\\u000a helical modes interacting in a triad. The use of helical modes implies that two shell variables are required for the velocity\\u000a as well as for the magnetic field. The advantage of the method is the automatic conservation of all the ideal quadratic

T. Lessinnes; F. Plunian; D. Carati

2009-01-01

330

No additional flow continua in magnetohydrodynamics  

NASA Astrophysics Data System (ADS)

The classical continuous spectrum of fluid flow found by C.M. Case [Phys. Fluids 3, 143 (1960)] is contained in the Alfvén and slow continua of magnetohydrodynamics (MHD). Contrary to several statements in the literature, most recently by S.N. Bhattacharyya and A. Bhattacharjee [Phys. Plasmas 4, 3744 (1997)], there are no additional flow continua in MHD. Additional Eulerian continuum modes do exist in both fluids and plasmas, but they only involve non-Lagrangian perturbations of the density or the entropy, not of the pressure and the magnetic field.

Goedbloed, J. P.; Beliën, A. J. C.; Holst, B. Van Der; Keppens, R.

2004-09-01

331

Magnetohydrodynamic turbulence in the solar wind  

NASA Technical Reports Server (NTRS)

The fluctuations in magnetic field and plasma velocity in solar wind, which possess many features of fully developed magnetohydrodynamic (MHD) turbulence, are discussed. Direct spacecraft observations from 0.3 to over 20 AU, remote sensing radio scintillation observations, numerical simulations, and various models provide complementary methods that show that the fluctuations in the wind parameters undergo significant dynamical evolution independent of whatever turbulence might exist in the solar photosphere and corona. The Cluster mission, with high time resolution particle and field measurements and its variable separation strategies, should be able to provide data for answering many questions on MHD turbulence.

Goldstein, Melvyn L.

1995-01-01

332

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

333

Application of a hot air turbine for efficiency improvement in MHD\\/steam power plants  

Microsoft Academic Search

It is possible to gain 2 percent to 3 percent efficiency points in the MHD\\/steam combined cycle by application of a hot air turbocompressor. This gain is accomplished without any increase of air preheat temperature. Moreover, the size of the steam boiler and turbines in the bottom plant is reduced in the arrangement here proposed, all the compressed and preheated

1979-01-01

334

A parametric study of 1000 MWe combined closed cycle MHD\\/system electrical power generating plants  

Microsoft Academic Search

A parametric study was carried out for different closed noble gas MHD cycles coupled to a direct coal-fired combustion system (and in most cases to a steam bottoming plant). For the description of the components, black-box models were used. The influence of the choice of the most important design parameters on the total system efficiency was quantified, and the performance

A. J. Geutjes; DJ Kleyn

1978-01-01

335

Alfven Wave Tomography for Cold MHD Plasmas  

SciTech Connect

Alfven waves propagation in slightly nonuniform cold plasmas is studied by means of ideal magnetohydrodynamics (MHD) nonlinear equations. The evolution of the MHD spectrum is shown to be governed by a matrix linear differential equation with constant coefficients determined by the spectrum of quasi-static plasma density perturbations. The Alfven waves are shown not to affect the plasma density inhomogeneities, as they scatter off of them. The application of the MHD spectrum evolution equation to the inverse scattering problem allows tomographic measurements of the plasma density profile by scanning the plasma volume with Alfven radiation.

I.Y. Dodin; N.J. Fisch

2001-09-07

336

Long-term Evolution of Decaying Magnetohydrodynamic Turbulence in the Multiphase Interstellar Medium  

NASA Astrophysics Data System (ADS)

Supersonic turbulence in the interstellar medium (ISM) is believed to decay rapidly within a flow crossing time irrespective of the degree of magnetization. However, this general consensus of decaying magnetohydrodynamic (MHD) turbulence relies on local isothermal simulations, which are unable to take into account the roles of the global structures of magnetic fields and the ISM. Utilizing three-dimensional MHD simulations including interstellar cooling and heating, we investigate decaying MHD turbulence within cold neutral medium sheets embedded in a warm neutral medium. The early evolution of turbulent kinetic energy is consistent with previous results for decaying compressible MHD turbulence characterized by rapid energy decay with a power-law form of Evpropt -1 and by a short decay time compared with the flow crossing time. If initial magnetic fields are strong and perpendicular to the sheet, however, long-term evolution of the kinetic energy shows that a significant amount of turbulent energy (~0.2E 0) still remains even after 10 flow crossing times for models with periodic boundary conditions. The decay rate is also greatly reduced as the field strength increases for such initial and boundary conditions, but not if the boundary conditions are those for a completely isolated sheet. We analyze velocity power spectra of the remaining turbulence to show that in-plane, incompressible motions parallel to the sheet dominate at later times.

Kim, Chang-Goo; Basu, Shantanu

2013-12-01

337

Potential Industrial Applications of Magnetohydrodynamics  

Microsoft Academic Search

Magnetohydrodynamic power generation has been presented as limited in application to large generating stations but offering the promise of reduced power cost to be achieved through heat rate improvement. The potential for industrial application will be broadened if generators can be made attractive in smaller ratings, if generating cost can be reduced, and if the generator can be made lighter

D. H. Marquis

1963-01-01

338

Research and Development Studies for MHD/Coal Power Flow-Train Components. Technical Progress Report, 1 September 1980-1 September 1981.  

National Technical Information Service (NTIS)

The aim of this program is to contribute to certain facets of the development of the MHD/coal power system, and particularly the CDIF of DOE with regard to its flow train. Consideration is given specifically to the electical power take-off, the diagnostic...

M. H. Bloom B. Cheo S. Kuo S. Lederman E. Levi

1981-01-01

339

Development of a prototypical MHD coal combustor  

Microsoft Academic Search

An MHD (magnetohydrodynamic) combustor design concept allows significant reduction of thermal stresses and decouples safety and operational reliability issues is under development. The design is easily scalable to much larger sizes, simplifies combustor maintenance, and is compatible with high-pressure\\/temperature cooling water. Essential features of the design are that gas pressure is contained by an uncooled shell made of stainless steel

G. Listvinsky; J. Alpay; L. Hill; K. King; D. Paul; D. Vanevenhoven; K. Natesan; D. Y. Wang

1989-01-01

340

Robust and Efficient Riemann Solvers for MHD  

NASA Astrophysics Data System (ADS)

Robust and efficient approximate Riemann solvers for magnetohydrodynamics (MHD) are constructed. Particularly, a family of positively conservative Harten-Lax-van Leer (HLL)-type Riemann solvers, the so-called HLLD (`D' denotes Discontinuities), HLLR (`R' denotes Rotational), HLLC (`C' denotes Contact), and HLL solvers, is systematically considered.

Miyoshi, T.; Kusano, K.

2008-04-01

341

Research and development studies for MHD/coal power flow train components. Technical progress report, 1 September 1979-31 August 1980  

SciTech Connect

The aim of this program is to contribute to certain facets of the development of the MHD/coal power system, and particularly the CDIF of DOE with regard to its flow train. Consideration is given specifically to the electrical power take-off, the diagnostic and instrumentation systems, the combustor and MHD channel technology, and electrode alternatives. Within the constraints of the program, high priorities were assigned to the problems of power take-off and the related characteristics of the MHD channel, and to the establishment of a non-intrusive, laser-based diagnostic system. The next priority was given to the combustor modeling and to a significantly improved analysis of particle combustion. Separate abstracts were prepared for nine of the ten papers included. One paper was previously included in the data base. (WHK)

Bloom, M. H.

1980-01-01

342

[Nonlinear magnetohydrodynamics  

SciTech Connect

Resistive MHD equilibrium, even for small resistivity, differs greatly from ideal equilibrium, as do the dynamical consequences of its instabilities. The requirement, imposed by Faraday`s law, that time independent magnetic fields imply curl-free electric fields, greatly restricts the electric fields allowed inside a finite-resistivity plasma. If there is no flow and the implications of the Ohm`s law are taken into account (and they need not be, for ideal equilibria), the electric field must equal the resistivity times the current density. The vanishing of the divergence of the current density then provides a partial differential equation which, together with boundary conditions, uniquely determines the scalar potential, the electric field, and the current density, for any given resistivity profile. The situation parallels closely that of driven shear flows in hydrodynamics, in that while dissipative steady states are somewhat more complex than ideal ones, there are vastly fewer of them to consider. Seen in this light, the vast majority of ideal MHD equilibria are just irrelevant, incapable of being set up in the first place. The steady state whose stability thresholds and nonlinear behavior needs to be investigated ceases to be an arbitrary ad hoc exercise dependent upon the whim of the investigator, but is determined by boundary conditions and choice of resistivity profile.

Not Available

1994-01-01

343

Status of power generation experiments in the NASA Lewis closed cycle MHD facility  

NASA Technical Reports Server (NTRS)

The design and operation of the closed cycle MHD facility is discussed and results obtained in recent experiments are presented. The main components of the facility are a compressor, recuperative heat exchanger, heater, nozzle, MHD channel with 28 pairs of thoriated tungsten electrodes, cesium condenser, and an argon cooler. The facility has been operated at temperatures up to 2100 K with a cesium-seeded argon working fluid. At low magnetic field strengths, the open circuit voltage, Hall voltage and short circuit current obtained are 90, 69, and 47 percent of the theoretical equilibrium values, respectively. Comparison of this data with a wall and boundary layer leakage theory indicates that the generator has shorting paths in the Hall direction.

Sovie, R. J.; Nichols, L. D.

1971-01-01

344

Summary and evaluation of the parametric study of potential early commercial MHD power plants (PSPEC)  

NASA Technical Reports Server (NTRS)

Two parallel contracted studies were conducted. Each contractor investigated three base cases and parametric variations about these base cases. Each contractor concluded that two of the base cases (a plant using separate firing of an advanced high temperature regenerative air heater with fuel from an advanced coal gasifier and a plant using an intermediate temperature metallic recuperative heat exchanger to heat oxygen enriched combustion air) were comparable in both performance and cost of electricity. The contractors differed in the level of their cost estimates with the capital cost estimates for the MHD topping cycle and the magnet subsystem in particular accounting for a significant part of the difference. The impact of the study on the decision to pursue a course which leads to an oxygen enriched plant as the first commercial MHD plant is described.

Staigner, P. J.; Abbott, J. M.

1980-01-01

345

Pulsed electromagnetic gas acceleration. [magnetohydrodynamics, plasma power sources and plasma propulsion  

NASA Technical Reports Server (NTRS)

Terminal voltage measurements with various cathodes and anodes in a high power, quasi-steady magnetoplasmadynamic (MPD) are discussed. The magnitude of the current at the onset of voltage fluctuations is shown to be an increasing function of cathode area and a weaker decreasing function of anode area. Tests with a fluted cathode indicated that the fluctuations originate in the plasma adjacent to the cathode rather than at the cathode surface. Measurements of radiative output from an optical cavity aligned to examine the current-carrying portion of a two-dimensional, 56 kA magnetoplasmadynamic discharge reveal no lasing in that region, consistent with calculations of electron excitation and resonance radiation trapping. A voltage-swept double probe technique allows single-shot determination of electron temperature and electron number density in the recombining MPD exhaust flow. Current distributions within the cavity of MPD hollow cathodes for various static prefills with no injected mass flow are examined.

Jahn, R. G.; Vonjaskowsky, W. F.; Clark, K. E.

1975-01-01

346

Real-time simulation of MHD\\/steam power plants by digital parallel processors  

Microsoft Academic Search

Attention is given to a large FORTRAN coded program which simulates the dynamic response of the MHD\\/steam plant on either a SEL 32\\/55 or VAX 11\\/780 computer. The code realizes a detailed first-principle model of the plant. Quite recently, in addition to the VAX 11\\/780, an AD-10 has been installed for usage as a real-time simulation facility. The parallel processor

R. M. Johnson; D. A. Rudberg

1981-01-01

347

An MHD model of the earth's magnetosphere  

NASA Technical Reports Server (NTRS)

It is pointed out that the earth's magnetosphere arises from the interaction of the solar wind with the earth's geomagnetic field. A global magnetohydrodynamics (MHD) model of the earth's magnetosphere has drawn much attention in recent years. In this model, MHD equations are used to describe the solar wind interaction with the magnetosphere. In the present paper, some numerical aspects of the model are considered. Attention is given to the ideal MHD equations, an equation of state for the plasma, the model as an initial- and boundary-value problem, the shock capturing technique, computational requirements and techniques for global MHD modeling, a three-dimensional mesh system employed in the global MHD model, and some computational results.

Wu, C. C.

1985-01-01

348

MHD performance demonstration experiment, October 1, 1080-September 30, 1981  

SciTech Connect

The Arnold Engineering Development Center (AEDC) has been under contract with the Department of Energy (DOE) since December 1973 to conduct a magnetohydrodynamic (MHD) High Performance Demonstration Experiment (HPDE). The objective of this experimental research is to demonstrate the attainment of MHD performance on a sufficiently large scale to verify that projected commercial MHD objectives are possible. This report describes the testing of the system under power-producing conditions during the period from October 1, 1980 to September 30, 1981. Experimental results have been obtained with the channel configured in the Faraday mode. Test conditions were selected to produce low supersonic velocity along the entire channel length. Tests have been conducted at magnetic fields up to 4.1 Tesla (T) (70% of design). Up to 30.5 MW of power has been produced to date (60% of design) for an enthalpy extraction of approximately 11%. The high Hall voltage transient, observed during the previous series of tests has been reduced. The reduction is mostly probably due to the fuel and seed being introduced simultaneously. The replacement of the ATJ graphite caps on the electrode walls with pyrolytic graphite caps has resulted in significantly higher surface temperature. As a result, the voltage drop is some 60% of the cold wall voltage drop during the previous series of tests. However, the absolute value of the present voltage drop is still greater than the original design predictions. Test results indicate, however, that the overall enthalpy extraction objective can be achieved.

Whitehead, G. L.; Christenson, L. S.; Felderman, E. J.; Lowry, R. L.; Bordenet, E. J.

1981-12-01

349

Global Magnetohydrodynamic Modeling of the Solar Corona  

NASA Technical Reports Server (NTRS)

Under this contract, we have continued our investigations of the large scale structure of the solar corona and inner heliosphere using global magnetohydrodynamic (MHD) simulations. These computations have also formed the basis for studies of coronal mass ejections (CMES) using realistic coronal configurations. We have developed a technique for computing realistic magnetohydrodynamic (MHD) computations of the solar corona and inner heliosphere. To perform computations that can be compared with specific observations, it is necessary to incorporate solar observations into the boundary conditions. We have used the Wilcox Solar Observatory synoptic maps (collected during a solar rotation by daily measurements of the line-of-sight magnetic field at central meridian) to specify the radial magnetic field (B,) at the photosphere. For the initial condition, we use a potential magnetic field consistent with the specified distribution of B, at the lower boundary, and a wind solution consistent with the specified plasma density and temperature at the solar surface. Together this initial condition forms a (non-equilibrium) approximation of the state of the solar corona for the time-dependent MHD computation. The MHD equations are then integrated in time to steady state. Here we describe solutions relevant to a recent solar eclipse, as well as Ulysses observations. We have also developed a model configuration of solar minimum, useful for studying CME initiation and propagation.

Linker, Jon A.

1997-01-01

350

Global magnetohydrodynamic simulations on multiple GPUs  

NASA Astrophysics Data System (ADS)

Global magnetohydrodynamic (MHD) models play the major role in investigating the solar wind-magnetosphere interaction. However, the huge computation requirement in global MHD simulations is also the main problem that needs to be solved. With the recent development of modern graphics processing units (GPUs) and the Compute Unified Device Architecture (CUDA), it is possible to perform global MHD simulations in a more efficient manner. In this paper, we present a global magnetohydrodynamic (MHD) simulator on multiple GPUs using CUDA 4.0 with GPUDirect 2.0. Our implementation is based on the modified leapfrog scheme, which is a combination of the leapfrog scheme and the two-step Lax-Wendroff scheme. GPUDirect 2.0 is used in our implementation to drive multiple GPUs. All data transferring and kernel processing are managed with CUDA 4.0 API instead of using MPI or OpenMP. Performance measurements are made on a multi-GPU system with eight NVIDIA Tesla M2050 (Fermi architecture) graphics cards. These measurements show that our multi-GPU implementation achieves a peak performance of 97.36 GFLOPS in double precision.

Wong, Un-Hong; Wong, Hon-Cheng; Ma, Yonghui

2014-01-01

351

Tokamak Magnetohydrodynamic Equilibrium States with Axisymmetric Boundary and a 3D Helical Core  

SciTech Connect

Magnetohydrodynamic (MHD) equilibrium states with imposed axisymmetric boundary are computed in which a spontaneous bifurcation develops to produce an internal three-dimensional (3D) configuration with a helical structure in addition to the standard axisymmetric system. Equilibrium states with similar MHD energy levels are shown to develop very different geometric structures. The helical equilibrium states resemble saturated internal kink mode structures.

Cooper, W. A.; Graves, J. P.; Pochelon, A.; Sauter, O.; Villard, L. [Ecole Polytechnique Federale de Lausanne (EPFL), Centre de Recherches en Physique des Plasmas, Association Euratom-Confederation Suisse, CH-1015 Lausanne (Switzerland)

2010-07-16

352

A Comparison of Two Intermediate State HLLC Solvers for Ideal Magnetohydrodynamics  

NASA Astrophysics Data System (ADS)

This paper compares a solver based on the HLLC (Harten-Lax-van Leer-contact wave) approximate nonlinear Riemann solver for gas dynamics for ideal magnetohydrodynamics (MHD) with the HLL, Roe, Linde, and Li solvers. Simulation results are given for three one-dimensional test cases not previously shown in the original paper presenting the smooth HLLC solver for MHD.

Gurski, K. F.

2008-04-01

353

MHD and Kinetic Modeling of the Ionospheres of Venus and Mars  

SciTech Connect

It is widely recognized that both Venus and Mars possess no significant global intrinsic magnetic fields, and that the solar wind interacts directly with the upper atmospheres and ionospheres of Venus and Mars. In addition, local crustal magnetic fields are also present in various regions at Mars, suggesting that some regions of the Martian ionosphere are influenced not only by the solar wind but also by the crustal magnetic field. Previous studies have suggested that the basic structures of the ionospheres of the planets can be described by fluid and MHD(magnetohydrodynamic) processes. Various models of the ionospheres of Venus and Mars based on the MHD formulation have been constructed during the last two decades. Although the MHD approach has been successful in reproducing the ionospheres of the planets, some studies have indicated that MHD modeling is not necessarily appropriate in the regions of the topside ionosphere, the ionopause, and the magnetosheath, where the ion kinetic processes are likely to play an important role. The kinetic processes in the topside ionosphere might have significant influences even in the lower ionosphere. Thanks to a great progress made for computer power as well as the efficiency of calculations of the hybrid model, high-resolution kinetic models of the solar wind interaction with Venus and Mars, which self-consistently include the ionosphere, have been developed. In this paper, status of MHD and kinetic modeling of the ionospheres of Venus and Mars is briefly reviewed.

Shinagawa, H.; Terada, N. [National Institute of Information and Communications Technology, Koganei, Tokyo 184-8795 (Japan)

2009-06-16

354

The magnetohydrodynamics Coal-Fired Flow Facility  

SciTech Connect

The purpose of this report is to provide the status of a multi-task research and development program in coal fired magnetohydrodynamics (MHD)/steam combined cycle power production. More detailed information on specific topics is presented in topical reports. Current emphasis is on developing technology for the Steam Bottoming Cycle Program. The approach being taken is to design test components that simulate the most important process variables, such as gas temperature, chemical composition, tube metal temperature, particulate loading, etc., to gain test data needed for scale-up to larger size components. Previous reports have provided comprehensive data on NO{sub x} and SO{sub x} control, radiant heat transfer, particulate control (baghouse and electrostatic precipitator), environmental monitoring, and analyses of test data on the convective heat transfer components (superheater and air heater). For this quarter, additional data on these subjects, plans for materials testing in future western coal tests and environmental and diagnostic results from the special tests on western coal are reported. Detailed data analyses will be contained in test reports, topical reports or technical papers.

Not Available

1992-04-01

355

Nuclear magnetohydrodynamic EMP, solar storms, and substorms  

SciTech Connect

In addition to a fast electromagnetic pulse (EMP), a high altitude nuclear burst produces a relatively slow magnetohydrodynamic EMP (MHD EMP), whose effects are like those from solar storm geomagnetically induced currents (SS-GIC). The MHD EMP electric field E [approx lt] 10[sup [minus] 1] V/m and lasts [approx lt] 10[sup 2] sec, whereas for solar storms E [approx gt] 10[sup [minus] 2] V/m and lasts [approx gt] 10[sup 3] sec. Although the solar storm electric field is lower than MHD EMP, the solar storm effects are generally greater due to their much longer duration. Substorms produce much smaller effects than SS-GIC, but occur much more frequently. This paper describes the physics of such geomagnetic disturbances and analyzes their effects.

Rabinowitz, M. (Electric Power Research Inst., Palo Alto, CA (United States)); Meliopoulous, A.P.S.; Glytsis, E.N. (Georgia Inst. of Tech., Atlanta, GA (United States). School of Electrical Engineering); Cokkinides, G.J. (Electrical Engineering Dept., Univ. of South Carolina, Columbia, SC (United States))

1992-10-20

356

Parametric study of prospective early commercial MHD power plants (PSPEC). General Electric Company, task 1: Parametric analysis  

NASA Technical Reports Server (NTRS)

The performance and cost of moderate technology coal-fired open cycle MHD/steam power plant designs which can be expected to require a shorter development time and have a lower development cost than previously considered mature OCMHD/steam plants were determined. Three base cases were considered: an indirectly-fired high temperature air heater (HTAH) subsystem delivering air at 2700 F, fired by a state of the art atmospheric pressure gasifier, and the HTAH subsystem was deleted and oxygen enrichment was used to obtain requisite MHD combustion temperature. Coal pile to bus bar efficiencies in ease case 1 ranged from 41.4% to 42.9%, and cost of electricity (COE) was highest of the three base cases. For base case 2 the efficiency range was 42.0% to 45.6%, and COE was lowest. For base case 3 the efficiency range was 42.9% to 44.4%, and COE was intermediate. The best parametric cases in bases cases 2 and 3 are recommended for conceptual design. Eventual choice between these approaches is dependent on further evaluation of the tradeoffs among HTAH development risk, O2 plant integration, and further refinements of comparative costs.

Marston, C. H.; Alyea, F. N.; Bender, D. J.; Davis, L. K.; Dellinger, T. C.; Hnat, J. G.; Komito, E. H.; Peterson, C. A.; Rogers, D. A.; Roman, A. J.

1980-01-01

357

Key contributions in MHD power generation. Quarterly technical progress report, September 1, 1979-November 30, 1979  

SciTech Connect

Separate entries were made in the data base for the four tasks which include: (1) investigation of electrical behavior in the vicinity of electrode and insulating walls; (2) studies of critical performance issues in the development of combustion disk generators; (3) development and testing of electrode modules, including studies of insulator properties; and (4) determination of coal combustion kinetics and ash behavior relevant to two-stage MHD combustors, and investigation of the mixing and flow aerodynamics of a high swirl geometry second stage. (WHK)

Louis, J F

1980-03-01

358

Steady-state axisymmetric nonlinear magnetohydrodynamic solutions with various boundary conditions  

NASA Astrophysics Data System (ADS)

Axisymmetric magnetohydrodynamics (MHD) can be invoked for describing astrophysical magnetized flows and formulated to model stellar magnetospheres including main-sequence stars (e.g. the Sun), compact stellar objects [e.g. magnetic white dwarfs (MWDs), radio pulsars, anomalous X-ray pulsars, magnetars, isolated neutron stars, etc.] and planets as a major step forward towards a full three-dimensional model construction. Using powerful and reliable numerical solvers based on two distinct finite-difference method and finite-element method schemes of algorithm, we examine axisymmetric steady-state or stationary MHD models in Throumoulopoulos & Tasso, finding that their separable semi-analytic non-linear solutions are actually not unique given their specific selection of several free functionals and chosen boundary conditions. Similar situations of multiple non-linear solutions with the same boundary conditions actually also happen to force-free magnetic field models of Low & Lou. The multiplicity of non-linear steady MHD solutions gives rise to differences in the total energies contained in the magnetic fields and flow velocity fields as well as in the asymptotic behaviours approaching infinity, which may in turn explain why numerical solvers tend to converge to a non-linear solution with a lower energy than the corresponding separable semi-analytic one. By properly adjusting model parameters, we invoke semi-analytic and numerical solutions to describe different kinds of scenarios, including nearly parallel case and the situation in which the misalignment between the plasma flow and magnetic field is considerable. We propose that these MHD models are capable of describing the magnetospheres of MWDs as examples of applications with moderate conditions (including magnetic field) where the typical values of several important parameters are consistent with observations. Physical parameters can also be estimated based on such MHD models directly. We discuss the challenges of developing numerical extrapolation MHD codes in view of the non-linear degeneracy.

Wang, Lile; Lou, Yu-Qing

2014-04-01

359

Quantitative, Comprehensive, Analytical Model for Magnetic Reconnection in Hall Magnetohydrodynamics  

SciTech Connect

Dissipation-independent, or 'fast', magnetic reconnection has been observed computationally in Hall magnetohydrodynamics (MHD) and predicted analytically in electron MHD. However, a quantitative analytical theory of reconnection valid for arbitrary ion inertial lengths, d{sub i}, has been lacking and is proposed here for the first time. The theory describes a two-dimensional reconnection diffusion region, provides expressions for reconnection rates, and derives a formal criterion for fast reconnection in terms of dissipation parameters and d{sub i}. It also confirms the electron MHD prediction that both open and elongated diffusion regions allow fast reconnection, and reveals strong dependence of the reconnection rates on d{sub i}.

Simakov, Andrei N.; Chacon, L. [Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

2008-09-05

360

Quantitative, comprehensive, analytical model for magnetic reconnection in Hall magnetohydrodynamics.  

PubMed

Dissipation-independent, or "fast", magnetic reconnection has been observed computationally in Hall magnetohydrodynamics (MHD) and predicted analytically in electron MHD. However, a quantitative analytical theory of reconnection valid for arbitrary ion inertial lengths, d{i}, has been lacking and is proposed here for the first time. The theory describes a two-dimensional reconnection diffusion region, provides expressions for reconnection rates, and derives a formal criterion for fast reconnection in terms of dissipation parameters and d{i}. It also confirms the electron MHD prediction that both open and elongated diffusion regions allow fast reconnection, and reveals strong dependence of the reconnection rates on d{i}. PMID:18851221

Simakov, Andrei N; Chacón, L

2008-09-01

361

Propagation of linear waves in relativistic anisotropic magnetohydrodynamics.  

PubMed

Gedalin [Phys. Rev. E 47, 4354 (1993)] derived a dispersion relation for linear waves in relativistic anisotropic Magnetohydrodynamics (MHD). This dispersion relation is used to point out the regions where the relativistic anisotropic MHD leads to new results that cannot be obtained using usual collisional relativistic MHD. This is highlighted by plotting a Fresnal ray surface. Conditions for the onset of firehose and mirror instabilities are also indicated. Such a study can be applied to astrophysical features such as pulsar winds, propagation of cosmic rays, etc. PMID:12513643

Gebretsadkan, W B; Kalra, G L

2002-11-01

362

Computation of Multi-region Relaxed Magnetohydrodynamic Equilibria  

SciTech Connect

We describe the construction of stepped-pressure equilibria as extrema of a multi-region, relaxed magnetohydrodynamic (MHD) energy functional that combines elements of ideal MHD and Taylor relaxation, and which we call MRXMHD. The model is compatible with Hamiltonian chaos theory and allows the three-dimensional MHD equilibrium problem to be formulated in a well-posed manner suitable for computation. The energy-functional is discretized using a mixed finite-element, Fourier representation for the magnetic vector potential and the equilibrium geometry; and numerical solutions are constructed using the stepped-pressure equilibrium code, SPEC. Convergence studies with respect to radial and Fourier resolution are presented.

S.R. Hudson, R.L. Dewar, G. Dennis, M.J. Hole, M. McGann, G. von Nessi and S. Lazerson

2013-03-29

363

Computation of multi-region relaxed magnetohydrodynamic equilibria  

SciTech Connect

We describe the construction of stepped-pressure equilibria as extrema of a multi-region, relaxed magnetohydrodynamic (MHD) energy functional that combines elements of ideal MHD and Taylor relaxation, and which we call MRXMHD. The model is compatible with Hamiltonian chaos theory and allows the three-dimensional MHD equilibrium problem to be formulated in a well-posed manner suitable for computation. The energy-functional is discretized using a mixed finite-element, Fourier representation for the magnetic vector potential and the equilibrium geometry; and numerical solutions are constructed using the stepped-pressure equilibrium code, SPEC. Convergence studies with respect to radial and Fourier resolution are presented.

Hudson, S. R.; Lazerson, S. [Princeton Plasma Physics Laboratory, P.O. Box 451, Princeton, New Jersey 08543 (United States); Dewar, R. L.; Dennis, G.; Hole, M. J.; McGann, M.; Nessi, G. von [Plasma Research Laboratory, Research School of Physics and Engineering, Australian National University, Canberra ACT 0200 (Australia)

2012-11-15

364

An HLLC Riemann solver for magneto-hydrodynamics  

NASA Astrophysics Data System (ADS)

This paper extends a class of approximate Riemann solvers devised by Harten, Lax and van Leer (HLL) for Euler equations of hydrodynamics to magneto-hydrodynamics (MHD) equations. In particular, we extend the two-state HLLC (HLL for contact wave) construction of Toro, Spruce and Speares to MHD equations. We derive a set of HLLC middle states that satisfies the conservation laws. Numerical examples are given to demonstrate that the new MHD-HLLC solver can achieve high numerical resolution, especially for resolving contact discontinuity. In addition, this new solver maintains a high computational efficiency when compared to Roe's approximate Riemann solver.

Li, Shengtai

2005-02-01

365

Solution to the MHD flow over a non-linear stretching sheet by homotopy perturbation method  

NASA Astrophysics Data System (ADS)

In this study, by means of homotopy perturbation method (HPM) an approximate solution of the magnetohydrodynamic (MHD) boundary layer flow is obtained. The main feature of the HPM is that it deforms a difficult problem into a set of problems which are easier to solve. HPM produces analytical expressions for the solution to nonlinear differential equations. The obtained analytic solution is in the form of an infinite power series. In this work, the analytical solution obtained by using only two terms from HPM solution. Comparisons with the exact solution and the solution obtained by the Pade approximants and shooting method show the high accuracy, simplicity and efficiency of this method.

Raftari, Behrouz; Mohyud-Din, Syed Tauseef; Yildirim, Ahmet

2011-02-01

366

Slip effects on the peristaltic transport of MHD fluid with variable viscosity  

NASA Astrophysics Data System (ADS)

This Letter concerns with the peristaltic analysis of MHD viscous fluid in a two-dimensional channel with variable viscosity under the effect of slip condition. A long wavelength and low Reynolds number assumption is used in the problem formulation. An exact solution is presented for the case of hydrodynamic fluid while for magnetohydrodynamic fluid a series solution is obtained in the small power of viscosity parameter. The salient features of pumping and trapping phenomena are discussed in detail through the numerical integration. It is noted that an increase in the slip parameter decreases the peristaltic pumping region. Moreover, the size of trapped bolus decreases by increasing the slip parameter.

Ali, N.; Hussain, Q.; Hayat, T.; Asghar, S.

2008-02-01

367

Comparative analysis of the Conceptual-design Studies of Potential Early Commercial MHD power plants (CSPEC)  

SciTech Connect

Tasks II and III of the Parametric Study of Potential Early Commercial MHD Plants (PSPEC) have essentially been completed. Task II (CSPEC) consisted of a conceptual design study of the MHD/steam plant that incorporated the use of oxygen enriched air preheated in a metallic heat exchanger as the combustor oxidant. This plant was found the most attractive for early commercial applications in Task I. In Task III the variation of performance and cost was investigated as a function of plant size. The efforts were performed by contractor teams led by Avco and General Electric Company. The Avco effort has been completed. The GE team has completed the plant design and performance studies but is presently reassessing the cost estimates for these plants. The contractors' results for the overall efficiencies are in reasonable agreement considering the slight differences in their plant designs. The Avco results varied from approx. 44 to 41% and GE's from approx. 43 to 39% as the plant size varied from approx. 1000 MW/sub e/ to 200 MW/sub e/. Both contractors predicted reasonable performance (approx. 42%) at a part load operating condition of 75% of full load. The Avco cost results were reasonably consistent with those presented in PSPEC and compare favorably with those for conventional coal-fired steam plants over the range of plant sizes from 200 to 950 MW/sub e/.

Sovie, R.J.; Winter, J.M.; Juhasz, A.J.; Berg, R.D.

1982-01-01

368

Sea-water magnetohydrodynamic propulsion for next-generation undersea vehicles. Annual report, 1 February 1989-31 January 1990  

SciTech Connect

Three tasks were performed in this report period. Their individual abstracts are summarized as follows: (I) Thruster Performance Modelings - The purpose of this work is to analyze underwater vehicle propulsion by applying Lorentz forces to the surrounding sea water. While this propulsion concept involves two different schemes, i.e. the external field method and the internal duct-type method, the current analysis focuses on the internal thruster scheme due to the space limitations and speed considerations. The theories of magnetohydrodynamic (MHD) pump jet propulsion are discussed. A so-called dual control volume analysis to model the MHD thruster, and calculations of vehicle velocity and power efficiency are presented. (II) Sea Water Conductivity Enhancement - This work discusses the mechanisms of enhancing the electric conductivity of sea water. The direct impact of conductivity enhancement of sea water is the improvement of propulsion performances of marine vehicles that use the magnetohydrodynamic thrusts of sea water. The performance improvement can be in energy efficiency or in vehicle speed. Injection of strong electrolytes (acids or bases) into the main sea water flow in the MHD channel appeared to be the most logical way of achieving the purpose. (III) Status of Current Superconductivity Works - A survey of recent research in both low -T{sub c} and high -T{sub c} superconductivities is provided. It is generally true that high -T{sub c} superconductors carry critical current densities several orders of magnitude less than those of low -T{sub c} ones.

Lin, T.F.; Gilbert, J.B.; Kossowsky, R.

1990-02-01

369

Program Plan for Development of Heat and Seed Recovery Components for a Coal-Fired, Open-Cycle MHD Power Plant.  

National Technical Information Service (NTIS)

A comprehensive plan for the development of the heat recovery and seed recovery (HRSR) components for an integrated open-cycle, coal-burning MHD power plant is outlined. The program should assure that the necessary engineering and design information will ...

T. R. Johnson

1978-01-01

370

Hall magnetohydrodynamic reconnection: The Geospace Environment Modeling challenge  

Microsoft Academic Search

Numerical results are presented on the Geospace Environment Modeling (GEM) reconnection challenge (and its variants) from the Hall magnetohydrodynamics (MHD) code developed at the University of Iowa (UI). Resistivity provides the mechanism for breaking field lines in this study. It is shown that the peak reconnection rate in the quasi-saturated regime is controlled dominantly by ions and has a weak

Z. W. Ma; A. Bhattacharjee

2001-01-01

371

Liquid magnetohydrodynamics — recent progress and future directions for fusion  

Microsoft Academic Search

This paper reports on recent research into magnetohydrodynamic (MHD) phenomena applicable to fusion technology. In Europe, experiments on the relative enhancement of heat transfer in liquid metal (LM) flows in ducts with electrically thin or insulated walls show a factor of two increase due to strong shear flow boundary layers when compared to slug flow solutions. This increase has no

Neil B. Morley; Sergey Smolentsev; Leopold Barleon; Igor R. Kirillov; Minoru Takahashi

2000-01-01

372

Magnetohydrodynamic generator scaling analysis for baseload commercial powerplants  

Microsoft Academic Search

Magnetohydrodynamic generator channel scaling analyses have been performed to establish the effect of generator size and oxygen enrichment on channel performance. These studies have shown that MHD generator channels can be designed to operate efficiently over the range of 250 to 2135. The optimum design conditions for each of the thermal inputs were established by investigating various combinations of electrical

D. W. Swallom; C. C. P. Pian

1983-01-01

373

The role of magnetohydrodynamics in heliospheric space plasma physics research  

Microsoft Academic Search

Magnetohydrodynamics (MHD) is a fairly recent extension of the field of fluid mechanics. While much remains to be done, it has successfully been applied to the contemporary field of heliospheric space plasma research to evaluate the ‘macroscopic picture’ of some vital topics via the use of conducting fluid equations and numerical modeling and simulations. Some representative examples from solar and

Murray Dryer; Zdenka Kopal Smith; Shi Tsan Wu

1988-01-01

374

Open-cycle MHD systems analysis. Final report  

SciTech Connect

Five variant configurations of a coal-burning open-cycle magnetohydrodynamic electric power generating facility were studied for evaluation as candidate first-generation power plants. A material and energy balance and cycle analysis was performed for each case to provide information for the conceptual designs and costing of all major MHD-related components and subsystems as well as specification of other state-of-the-art components. An economic comparison was made of each design by developing the cost-of-electricity based on component costs, estimates of operation and maintenance requirements and the performance of each plant from the system analyses. An overall description of each plant is provided along with discussions of critical component and process development. An oxygen-enriched OCMHD plant design was identified as an attractive candidate for first-generation utility service. This plant design appears to offer competitive costs of electricity and minimizes development risk.

Lippert, T.E.; Weeks, K.D.

1980-02-01

375

Retrofit of a coal-fired open-cycle liquid-metal MHD to steam power plants  

SciTech Connect

The application of the new, coal-fired open-cycle liquid-metal MHD (OC-LMMHD) energy-conversion system to the retrofit of an existing, oil- or gas-fired conventional steam power plant is evaluated. The criteria used to evaluate the retrofit are the net plant efficiency and the cost benefit relative to other options, i.e., continuing to burn oil, a conventional retrofit to burn coal (if possible), and an over-the-fence gasifier for boilers that cannot burn coal directly. The efficiency and cost calculations are based on a specific existing steam plant, and a detailed description of the retrofit plant. The unique capability of the OC-LMMHD cycle to control the pollutants normally associated with burning coal is discussed.

Pierson, E.S.; Herman, H.; Petrick, M.; Grammel, S.J.; Dubey, G.

1981-01-01

376

MHD coal-fired flow facility. Annual technical progress report, October 1979-September 1980  

SciTech Connect

The University of Tennessee Space Institute (UTSI) reports on significant activity, task status, planned research, testing, development, and conclusions for the Magnetohydrodynamics (MHD) Coal-Fired Flow Faclity (CFFF) and the Energy Conversion Facility (ECF).

Alstatt, M.C.; Attig, R.C.; Brosnan, D.A.

1981-03-01

377

Development of Materials for Open-Cycle MHD. Quarterly Report for the Period Ending March 1984.  

National Technical Information Service (NTIS)

Pacific Northwest Laboratory (PNL) is conducting a study of channel components for open-cycle, coal-fired magnetohydrodynamic (MHD) generators. Specifically, electrodes and insulators are being developed. The electrical conductivity has been measured on s...

D. D. Marchant J. L. Bates

1984-01-01

378

The Signature of Initial Conditions on Magnetohydrodynamic Turbulence  

NASA Astrophysics Data System (ADS)

We demonstrate that the initial correlation between velocity and current density fluctuations can lead to the formation of enormous current sheets in freely evolving magnetohydrodynamic (MHD) turbulence. These coherent structures are observed at the peak of the energy dissipation rate and are the carriers of long-range correlations despite all of the nonlinear interactions during the formation of turbulence. The size of these structures spans our computational domain, dominating the scaling of the energy spectrum, which follows a Evpropk –2 power law. As the Reynolds number increases, the curling of the current sheets due to Kelvin-Helmholtz-type instabilities and reconnection modifies the scaling of the energy spectrum from k –2 toward k –5/3. This transition occurs due to the decorrelation of the velocity and the current density which is proportional to Re_\\lambda ^{-3/2}. Finite Reynolds number behavior is observed without reaching a finite asymptote for the energy dissipation rate even for a simulation of Re? ~= 440 with 20483 grid points. This behavior demonstrates that even state-of-the-art numerical simulations of the highest Reynolds numbers can be influenced by the choice of initial conditions and consequently they are inadequate to deduce unequivocally the fate of universality in MHD turbulence. Implications for astrophysical observations are discussed.

Dallas, V.; Alexakis, A.

2014-06-01

379

Supersonic regime of the Hall-magnetohydrodynamics resistive tearing instability  

SciTech Connect

An earlier analysis of the Hall-magnetohydrodynamics (MHD) tearing instability [E. Ahedo and J. J. Ramos, Plasma Phys. Controlled Fusion 51, 055018 (2009)] is extended to cover the regime where the growth rate becomes comparable or exceeds the sound frequency. Like in the previous subsonic work, a resistive, two-fluid Hall-MHD model with massless electrons and zero-Larmor-radius ions is adopted and a linear stability analysis about a force-free equilibrium in slab geometry is carried out. A salient feature of this supersonic regime is that the mode eigenfunctions become intrinsically complex, but the growth rate remains purely real. Even more interestingly, the dispersion relation remains of the same form as in the subsonic regime for any value of the instability Mach number, provided only that the ion skin depth is sufficiently small for the mode ion inertial layer width to be smaller than the macroscopic lengths, a generous bound that scales like a positive power of the Lundquist number.

Ahedo, Eduardo [Universidad Politecnica de Madrid, 28040 Madrid (Spain); Ramos, Jesus J. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

2012-07-15

380

Diagnostic Techniques in Combustion MHD Flows  

Microsoft Academic Search

The US national program in MHD electric power generation is predicated on the direct firing of pulverized coal, using MHD as a topping cycle for a regular steam plant. Extensive system studies predict the thermal efficiency of a large combined MHD\\/Steam plant will be in the range 50 to 55% compared with 35 to 40% for a conventional steam plant.

S. A. Self

1979-01-01

381

Diagnostic development and support of MHD test facilities. Final progress report, March 1980--March 1994  

SciTech Connect

The Diagnostic Instrumentation and Analysis Laboratory (DIAL) at Mississippi State University (MSU), under U.S. Department of Energy (DOE) Contract No. DE-AC02-80ET-15601, Diagnostic Development and Support of MHD Test Facilities, developed diagnostic instruments for magnetohydrodynamic (MHD) power train data acquisition and for support of MHD component development test facilities. Microprocessor-controlled optical instruments, initially developed for Heat Recovery/Seed Recovery (HRSR) support, were refined, and new systems to measure temperatures and gas-seed-slag stream characteristics were developed. To further data acquisition and analysis capabilities, the diagnostic systems were interfaced with DIAL`s computers. Technical support was provided for the diagnostic needs of the national MHD research effort. DIAL personnel also cooperated with government agencies and private industries to improve the transformation of research and development results into processes, products and services applicable to their needs. The initial contract, Testing and Evaluation of Heat Recovery/Seed Recovery, established a data base on heat transfer, slagging effects on heat transfer surfaces, metal durability, secondary combustor performance, secondary combustor design requirements, and other information pertinent to the design of HR/SR components at the Coal-Fired Flow Facility (CFFF). To accomplish these objectives, a combustion test stand was constructed that simulated MHD environments, and mathematical models were developed and evaluated for the heat transfer in hot-wall test sections. Two transitions occurred during the span of this contract. In May 1983, the objectives and title of the contract changed from Testing and Evaluation of Heat Recovery/Seed Recovery to Diagnostic Development and Support of MHD Test Facilities. In July 1988, the research laboratory`s name changed from the MHD Energy Center to the Diagnostic Instrumentation and Analysis Laboratory.

Not Available

1995-02-01

382

Comparative analysis of the conceptual design studies of potential early commercial MHD power plants (CSPEC)  

NASA Technical Reports Server (NTRS)

A conceptual design study of the MHD/steam plant that incorporates the use of oxygen enriched air preheated in a metallic heat exchanger as the combustor oxidant showed that this plant is the most attractive for early commercial applications. The variation of performance and cost was investigated as a function of plant size. The contractors' results for the overall efficiencies are in reasonable agreement considering the slight differences in their plant designs. NASA LeRC is reviewing cost and performance results for consistency with those of previous studies, including studies of conventional steam plants. LeRC in house efforts show that there are still many tradeoffs to be considered for these oxygen enriched plants and considerable variations can be made in channel length and level of oxygen enrichment with little change in overall plant efficiency.

Sovie, R. J.; Winter, J. M.; Juhasz, A. J.; Berg, R. D.

1982-01-01

383

Closed cycle MHD power generation experiments using a helium-cesium working fluid in the NASA Lewis Facility  

NASA Technical Reports Server (NTRS)

The MHD channel in the NASA Lewis Research Center was redesigned and used in closed cycle power generation experiments with a helium-cesium working fluid. The cross sectional dimensions of the channel were reduced to 5 by 16.5 cm to allow operation over a variety of conditions. Experiments have been run at temperatures of 1900-2100 K and Mach numbers from 0.3 to 0.55 in argon and 0.2 in helium. Improvements in Hall voltage isolation and seed vaporization techniques have resulted in significant improvements in performance. Typical values obtained with helium are Faraday open circuit voltage 141 V (92% of uBh) at a magnetic field strength of 1.7 T, power outputs of 2.2 kw for tests with 28 electrodes and 2.1 kw for tests with 17 electrodes. Power densities of 0.6 MW/cu m and Hall fields of about 1100 V/m were obtained in the tests with 17 electrodes, representing a factor of 18 improvement over previously reported results. The V-I curves and current distribution data indicate that while near ideal equilibrium performance is obtained under some conditions, no nonequilibrium power has been generated to date.

Sovie, R. J.

1976-01-01

384

System study of an MHD/gas turbine combined-cycle baseload power plant. HTGL report No. 134  

SciTech Connect

The MHD/gas turbine combined-cycle system has been designed specifically for applications where the availability of cooling water is very limited. The base case systems which were studied consisted of an MHD plant with a gas turbine bottoming plant, and required no cooling water. The gas turbine plant uses only air as its working fluid and receives its energy input from the MHD exhaust gases by means of metal tube heat exchangers. In addition to the base case systems, vapor cycle variation systems were considered which included the addition of a vapor cycle bottoming plant to improve the thermal efficiency. These systems required a small amount of cooling water. The MHD/gas turbine systems were modeled with sufficient detail, using realistic component specifications and costs, so that the thermal and economic performance of the system could be accurately determined. Three cases of MHD/gas turbine systems were studied, with Case I being similar to an MHD/steam system so that a direct comparison of the performances could be made, with Case II being representative of a second generation MHD system, and with Case III considering oxygen enrichment for early commercial applications. The systems are nominally 800 MW/sub e/ to 1000 MW/sub e/ in size. The results show that the MHD/gas turbine system has very good thermal and economic performances while requiring either little or no cooling water. Compared to the MHD/steam system which has a cooling tower heat load of 720 MW, the Base Case I MHD/gas turbine system has a heat rate which is 13% higher and a cost of electricity which is only 7% higher while requiring no cooling water. Case II results show that an improved performance can be expected from second generation MHD/gas turbine systems. Case III results show that an oxygen enriched MHD/gas turbine system may be attractive for early commercial applications in dry regions of the country.

Annen, K.D.

1981-08-01

385

Method for manufacturing magnetohydrodynamic electrodes  

DOEpatents

A method of manufacturing electrodes for use in a magnetohydrodynamic (MHD) generator comprising the steps of preparing a billet having a core 10 of a first metal, a tubular sleeve 12 of a second metal, and an outer sheath 14, 16, 18 of an extrusile metal; evacuating the space between the parts of the assembled billet; extruding the billet; and removing the outer jacket 14. The extruded bar may be made into electrodes by cutting and bending to the shape required for an MDH channel frame. The method forms a bond between the first metal of the core 10 and the second metal of the sleeve 12 strong enough to withstand a hot and corrosive environment.

Killpatrick, Don H. (Orland Park, IL); Thresh, Henry R. (Palos Heights, IL)

1982-01-01

386

Gas Core Reactor Numerical Simulation Using a Coupled MHD-MCNP Model  

NASA Technical Reports Server (NTRS)

Analysis is provided in this report of using two head-on magnetohydrodynamic (MHD) shocks to achieve supercritical nuclear fission in an axially elongated cylinder filled with UF4 gas as an energy source for deep space missions. The motivation for each aspect of the design is explained and supported by theory and numerical simulations. A subsequent report will provide detail on relevant experimental work to validate the concept. Here the focus is on the theory of and simulations for the proposed gas core reactor conceptual design from the onset of shock generations to the supercritical state achieved when the shocks collide. The MHD model is coupled to a standard nuclear code (MCNP) to observe the neutron flux and fission power attributed to the supercritical state brought about by the shock collisions. Throughout the modeling, realistic parameters are used for the initial ambient gaseous state and currents to ensure a resulting supercritical state upon shock collisions.

Kazeminezhad, F.; Anghaie, S.

2008-01-01

387

Pulsar Magnetohydrodynamic Winds  

NASA Astrophysics Data System (ADS)

The acceleration and collimation/decollimation of relativistic magnetocentrifugal winds are discussed concerning a cold plasma from a strongly magnetized, rapidly rotating neutron star in a steady axisymmetric state based on ideal magnetohydrodynamics. There exist unipolar inductors associated with the field line angular frequency, ?, at the magnetospheric base surface, SB, with a huge potential difference between the poles and the equator, which drive electric current through the pulsar magnetosphere. Any ``current line'' must emanate from one terminal of the unipolar inductor and return to the other, converting the Poynting flux to the kinetic flux of the wind at finite distances. In a plausible field structure satisfying the transfield force-balance equation, the fast surface, SF, must exist somewhere between the subasymptotic and asymptotic domains, i.e., at the innermost point along each field line of the asymptotic domain of \\varpaA2/\\varpi2 ? 1, where \\varpiA is the Alfvénic axial distance. The criticality condition at SF yields the Lorentz factor, ?F = ?\\varepsilon1/3, and the angular momentum flux, ?, as the eigenvalues in terms of the field line angular velocity, ?, the mass flux per unit flux tube, ?, and one of the Bernoulli integrals, ??, which are assumed to be specifiable as the boundary conditions at SB. The other Bernoulli integral, ??, is related to ?? as ?? = ??[1-(?2\\varpiA2/c2)]-1, and both ?? and \\varpiA2 are eigenvalues to be determined by the criticality condition at SF. Ongoing MHD acceleration is possible in the superfast domain. This fact may be helpful in resolving a discrepancy between the wind theory and the Crab-nebula model. It is argued that the ``anti-collimation theorem'' holds for relativistic winds, based on the curvature of field streamlines determined by the transfield force balance. The ``theorem'' combines with the ``current-closure condition'' as a global condition in the wind zone to produce a two-component ``quasi-conical'' field structure as one of the basic properties of MHD outflows of centrifugal origin in the pulsar magnetosphere.

Okamoto, Isao; Sigalo, Friday B.

2006-12-01

388

Coronal magnetohydrodynamic waves and oscillations: observations and quests.  

PubMed

Coronal seismology, a new field of solar physics that emerged over the last 5 years, provides unique information on basic physical properties of the solar corona. The inhomogeneous coronal plasma supports a variety of magnetohydrodynamics (MHD) wave modes, which manifest themselves as standing waves (MHD oscillations) and propagating waves. Here, we briefly review the physical properties of observed MHD oscillations and waves, including fast kink modes, fast sausage modes, slow (acoustic) modes, torsional modes, their diagnostics of the coronal magnetic field, and their physical damping mechanisms. We discuss the excitation mechanisms of coronal MHD oscillations and waves: the origin of the exciter, exciter propagation, and excitation in magnetic reconnection outflow regions. Finally, we consider the role of coronal MHD oscillations and waves for coronal heating, the detectability of various MHD wave types, and we estimate the energies carried in the observed MHD waves and oscillations: Alfvénic MHD waves could potentially provide sufficient energy to sustain coronal heating, while acoustic MHD waves fall far short of the required coronal heating rates. PMID:16414888

Aschwanden, Markus J

2006-02-15

389

Numerical simulations for MHD coronal seismology  

NASA Astrophysics Data System (ADS)

Magnetohydrodynamic (MHD) processes are important for the transfer of energy over large scales in plasmas and so are essential to understanding most forms of dynamical activity in the solar atmosphere. The introduction of transverse structuring into models for the corona modifies the behavior of MHD waves through processes such as dispersion and mode coupling. Exploiting our understanding of MHD waves with the diagnostic tool of coronal seismology relies upon the development of sufficiently detailed models to account for all the features in observations. The development of realistic models appropriate for highly structured and dynamical plasmas is often beyond the domain of simple mathematical analysis and so numerical methods are employed. This paper reviews recent numerical results for seismology of the solar corona using MHD.

Pascoe, David James

2014-07-01

390

Perfect magnetohydrodynamics as a field theory  

SciTech Connect

We propose the generally covariant action for the theory of a self-coupled complex scalar field and electromagnetism which by virtue of constraints is equivalent, in the regime of long wavelengths, to perfect magnetohydrodynamics (MHD). We recover from it the Euler equation with Lorentz force, and the thermodynamic relations for a prefect fluid. The equation of state of the latter is related to the scalar field's self potential. We introduce 1+3 notation to elucidate the relation between MHD and field variables. In our approach the requirement that the scalar field be single valued leads to the quantization of a certain circulation in steps of ({Dirac_h}/2{pi}); this feature leads, in the classical limit, to the conservation of that circulation. The circulation is identical to that in Oron's generalization of Kelvin's circulation theorem to perfect MHD; we here characterize the new conserved helicity associated with it. We also demonstrate the existence for MHD of two Bernoulli-like theorems for each spacetime symmetry of the flow and geometry; one of these is pertinent to suitably defined potential flow. We exhibit the conserved quantities explicitly in the case that two symmetries are simultaneously present, and give examples. Also in this case we exhibit a new conserved MHD circulation distinct from Oron's, and provide an example.

Bekenstein, Jacob D.; Betschart, Gerold [Racah Institute of Physics, Hebrew University of Jerusalem, Jerusalem 91904 (Israel)

2006-10-15

391

RESONANCE BROADENING AND HEATING OF CHARGED PARTICLES IN MAGNETOHYDRODYNAMIC TURBULENCE  

SciTech Connect

The heating, acceleration, and pitch-angle scattering of charged particles by magnetohydrodynamic (MHD) turbulence are important in a wide range of astrophysical environments, including the solar wind, accreting black holes, and galaxy clusters. We simulate the interaction of high-gyrofrequency test particles with fully dynamical simulations of subsonic MHD turbulence, focusing on the parameter regime with {beta} {approx} 1, where {beta} is the ratio of gas to magnetic pressure. We use the simulation results to calibrate analytical expressions for test particle velocity-space diffusion coefficients and provide simple fits that can be used in other work. The test particle velocity diffusion in our simulations is due to a combination of two processes: interactions between particles and magnetic compressions in the turbulence (as in linear transit-time damping; TTD) and what we refer to as Fermi Type-B (FTB) interactions, in which charged particles moving on field lines may be thought of as beads sliding along moving wires. We show that test particle heating rates are consistent with a TTD resonance that is broadened according to a decorrelation prescription that is Gaussian in time (but inconsistent with Lorentzian broadening due to an exponential decorrelation function, a prescription widely used in the literature). TTD dominates the heating for v{sub s} >> v{sub A} (e.g., electrons), where v{sub s} is the thermal speed of species s and v{sub A} is the Alfven speed, while FTB dominates for v{sub s} << v{sub A} (e.g., minor ions). Proton heating rates for {beta} {approx} 1 are comparable to the turbulent cascade rate. Finally, we show that velocity diffusion of collisionless, large gyrofrequency particles due to large-scale MHD turbulence does not produce a power-law distribution function.

Lynn, Jacob W. [Physics Department, University of California, Berkeley, CA 94720 (United States); Parrish, Ian J.; Quataert, Eliot [Astronomy Department and Theoretical Astrophysics Center, University of California, Berkeley, CA 94720 (United States); Chandran, Benjamin D. G., E-mail: jacob.lynn@berkeley.edu [Space Science Center and Department of Physics, University of New Hampshire, Durham, NH 03824 (United States)

2012-10-20

392

DIFFUSIVE ACCELERATION OF PARTICLES AT OBLIQUE, RELATIVISTIC, MAGNETOHYDRODYNAMIC SHOCKS  

SciTech Connect

Diffusive shock acceleration (DSA) at relativistic shocks is expected to be an important acceleration mechanism in a variety of astrophysical objects including extragalactic jets in active galactic nuclei and gamma-ray bursts. These sources remain good candidate sites for the generation of ultrahigh energy cosmic rays. In this paper, key predictions of DSA at relativistic shocks that are germane to the production of relativistic electrons and ions are outlined. The technique employed to identify these characteristics is a Monte Carlo simulation of such diffusive acceleration in test-particle, relativistic, oblique, magnetohydrodynamic (MHD) shocks. Using a compact prescription for diffusion of charges in MHD turbulence, this approach generates particle angular and momentum distributions at any position upstream or downstream of the shock. Simulation output is presented for both small angle and large angle scattering scenarios, and a variety of shock obliquities including superluminal regimes when the de Hoffmann-Teller frame does not exist. The distribution function power-law indices compare favorably with results from other techniques. They are found to depend sensitively on the mean magnetic field orientation in the shock, and the nature of MHD turbulence that propagates along fields in shock environs. An interesting regime of flat-spectrum generation is addressed; we provide evidence for it being due to shock drift acceleration, a phenomenon well known in heliospheric shock studies. The impact of these theoretical results on blazar science is outlined. Specifically, Fermi Large Area Telescope gamma-ray observations of these relativistic jet sources are providing significant constraints on important environmental quantities for relativistic shocks, namely, the field obliquity, the frequency of scattering, and the level of field turbulence.

Summerlin, Errol J. [Heliospheric Physics Laboratory, Code 672, NASA's Goddard Space Flight Center, Greenbelt, MD 20770 (United States); Baring, Matthew G., E-mail: errol.summerlin@nasa.gov, E-mail: baring@rice.edu [Department of Physics and Astronomy, MS 108, Rice University, Houston, TX 77251 (United States)

2012-01-20

393

MHD instabilities  

Microsoft Academic Search

The MHD equations are considered along with the Rayleigh-Taylor instability, linearized equations and the energy principle, toroidal instabilities, high beta tokamaks, nonlinear instability theory, resistive instabilities, and a comparison between theory and experiment. The characteristics of the MHD equilibrium are examined, taking into account force balance equations, surface quantities, the q-value, the Grad-Shafranov equation, an example of bifurcation related to

G. Bateman

1978-01-01

394

System study of an MHD\\/gas turbine combined-cycle baseload power plant. HTGL report No. 134  

Microsoft Academic Search

The MHD\\/gas turbine combined-cycle system has been designed specifically for applications where the availability of cooling water is very limited. The base case systems which were studied consisted of an MHD plant with a gas turbine bottoming plant, and required no cooling water. The gas turbine plant uses only air as its working fluid and receives its energy input from

Annen

1981-01-01

395

System Study of an MHD/Gas Turbine Combined-Cycle Baseload Power Plant. HTGL Report No. 134.  

National Technical Information Service (NTIS)

The MHD/gas turbine combined-cycle system has been designed specifically for applications where the availability of cooling water is very limited. The base case systems which were studied consisted of an MHD plant with a gas turbine bottoming plant, and r...

K. D. Annen

1981-01-01

396

Conceptual design of a space-based multimegawatt MHD power system, task 1 topical report; Volume 1: Technical discussion. Topical report  

SciTech Connect

This Topical Report presents the results of Task 1 of the Feasibility Assessment for Space Based Multimegawatt MHD Power Systems program. It consists of two volumes. Volume 1 contains the results of the work performed in Task 1 as presented and discussed in Sections 2 through 6. Section 2 is an executive summary of the work. Section 3 contains a complete description of the space based multimegawatt MHD power system conceptual design. System performance and operations characteristics are also identified. It has been assumed in Task 1 that the system provides power to a Neutral Particle Beam (NPB) Weapon, for which generic load requirements are presented. Integration of the power system and NPB with alternative space launch vehicles is also discussed in this section. Section 4 contains a discussion of key technical issues and questions requiring additional investigation. Section 5 presents the Research and Development plan which is proposed for Task 2. Conclusions and Recommendations are contained in Section 6. Volume 2 of the report contains the System Requirements, Design Guidelines and Assumptions for the space based multimegawatt MHD power system. This is an initial system specification document which will be refined during the course of Task 2.

Dana, R.A.

1988-01-01

397

Broken Ergodicity in MHD Turbulence  

NASA Technical Reports Server (NTRS)

Ideal magnetohydrodynamic (MHD) turbulence may be represented by finite Fourier series, where the inherent periodic box serves as a surrogate for a bounded astrophysical plasma. Independent Fourier coefficients form a canonical ensemble described by a Gaussian probability density function containing a Hermitian covariance matrix with positive eigenvalues. The eigenvalues at lowest wave number can be very small, resulting in a large-scale coherent structure: a turbulent dynamo. This is seen in computations and a theoretical explanation in terms of 'broken ergodicity' contains Taylor s theory of force-free states. An important problem for future work is the case of real, i.e., dissipative flows. In real flows, broken ergodicity and coherent structure are still expected to occur in MHD turbulence at the largest scale, as suggested by low resolution simulations. One challenge is to incorporate coherent structure at the largest scale into the theory of turbulent fluctuations at smaller scales.

Shebalin, John V.

2010-01-01

398

Low-frequency circuit analysis of MHD-EMP-induced transients on three-phase distribution systems  

SciTech Connect

The magnetohydrodynamic electromagnetic pulse (MHD-EMP) generated by a nuclear explosion in the earth's ionosphere is believed by a number of researchers to pose a potentially severe threat to long electric utility transmission and distribution systems in the United States. The disturbances caused by MHD-EMP are similar to the electromagnetic transients caused by solar-induced geomagnetic storms, but are generally expected to be more intense with shorter durations. Recent solar-induced storms have caused appreciable damage to electric utility equipment in Canada and the northern United States. In March of 1989, a solar-induced geomagnetic storm caused a blackout of the Hydro-Quebec power system in the province of Quebec, failure of step-up power transformers at the Salem Nuclear Generating Plant of the Public Service Electric and Gas Company, and a number of less severe power disruptions in the United States. Since the amplitudes of MHD-EMP induced transients are expected to be stronger than those produced by solar-induced geomagnetic storms, unprotected electric utility power systems may be quite vulnerable to MHD-EMP.

Mayhall, D.J.; Yee, J.H.

1992-07-01

399

Low-frequency circuit analysis of MHD-EMP-induced transients on three-phase distribution systems  

SciTech Connect

The magnetohydrodynamic electromagnetic pulse (MHD-EMP) generated by a nuclear explosion in the earth`s ionosphere is believed by a number of researchers to pose a potentially severe threat to long electric utility transmission and distribution systems in the United States. The disturbances caused by MHD-EMP are similar to the electromagnetic transients caused by solar-induced geomagnetic storms, but are generally expected to be more intense with shorter durations. Recent solar-induced storms have caused appreciable damage to electric utility equipment in Canada and the northern United States. In March of 1989, a solar-induced geomagnetic storm caused a blackout of the Hydro-Quebec power system in the province of Quebec, failure of step-up power transformers at the Salem Nuclear Generating Plant of the Public Service Electric and Gas Company, and a number of less severe power disruptions in the United States. Since the amplitudes of MHD-EMP induced transients are expected to be stronger than those produced by solar-induced geomagnetic storms, unprotected electric utility power systems may be quite vulnerable to MHD-EMP.

Mayhall, D.J.; Yee, J.H.

1992-07-01

400

RESIDUAL ENERGY IN MAGNETOHYDRODYNAMIC TURBULENCE  

SciTech Connect

There is mounting evidence in solar wind observations and in numerical simulations that kinetic and magnetic energies are not in equipartition in magnetohydrodynamic (MHD) turbulence. The origin of their mismatch, the residual energy E{sub r} = E{sub v} - E{sub b} , is not understood well. In the present work this effect is studied analytically in the regime of weak MHD turbulence. We find that residual energy is spontaneously generated by turbulent dynamics, and it has a negative sign, in good agreement with the observations. We find that the residual energy condenses around k {sub ||} = 0 with its k {sub ||}-spectrum broadening linearly with k{sub perpendicular}, where k{sub ||} and k{sub perpendicular} are the wavenumbers parallel and perpendicular to the background magnetic field, and the field-perpendicular spectrum of the residual energy has the scaling E{sub r} (k{sub perpendicular}){proportional_to}k {sup -1}{sub perpendicular} in the inertial interval. These results are found to be in agreement with numerical simulations. We propose that residual energy plays a fundamental role in Alfvenic turbulence and it should be taken into account for the correct interpretation of observational and numerical data.

Wang Yuxuan; Boldyrev, Stanislav; Perez, Jean Carlos [Department of Physics, University of Wisconsin, Madison, WI 53706 (United States)

2011-10-20

401

Impact of measurement uncertainties on universal scaling of MHD turbulence  

NASA Astrophysics Data System (ADS)

Quantifying the scaling of fluctuations in the solar wind is central to testing predictions of turbulence theories. We study spectral features of Alfvénic turbulence in fast solar wind. We propose a general, instrument-independent method to estimate the uncertainty in velocity fluctuations obtained by in situ satellite observations in the solar wind. We show that when the measurement uncertainties of the velocity fluctuations are taken into account the less energetic Elsasser spectrum obeys a unique power law scaling throughout the inertial range as prevailing theories of magnetohydrodynamic (MHD) turbulence predict. Moreover, in the solar wind interval analysed, the two Elsasser spectra are observed to have the same scaling exponent ? = -1.54 throughout the inertial range.

Gogoberidze, G.; Chapman, S. C.; Hnat, B.; Dunlop, M. W.

2012-10-01

402

MHD Control of Oblique Detonation Waves  

NASA Astrophysics Data System (ADS)

Based on the Euler equation, the hybrid Roe/HLL scheme is employed to simulate the oblique detonation waves (ODWs). Furthermore, magnetohydrodynamic (MHD) control of both stable and unstable ODWs is investigated. It is shown that the stable ODW wave front can be controlled to the desired position under different inflow Mach numbers. However, for an unstable ODW, it is difficult for the MHD control to return the ODW front, but the unstable ODW turns to be stable with the Lorentz force applied in proper direction.

Sun, Xiao-Hui; Chen, Zhi-Hua; Zhang, Huan-Hao

2011-01-01

403

Closed cycle MHD power generation experiments using a helium-cesium working fluid in the NASA Lewis Facility  

NASA Technical Reports Server (NTRS)

A MHD channel, which was previously operated for over 500 hours of thermal operation, ten thermal cycles, and 200 cesium injection tests, was removed from the facility and redesigned. The cross sectional dimensions of the channel were reduced to 5 by 16.5 cm to allow operation over a variety of conditions. The redesigned channel has been operated for well over 300 hours, 10 thermal cycles, and 150 cesium injection tests with no problems. Experiments have been run at temperatures of 1900-2100 K and Mach numbers from 0.3 to 0.55 in argon and 0.2 in helium. The best results to date have been obtained in the helium tests. Power outputs of 2.2 kw for tests with 28 electrodes and 2.1 kw for tests with 17 electrodes were realized. Power densities of 0.6 MW/cu m and Hall fields of about 1,100 V/m were obtained in the tests with 17 electrodes.

Sovie, R. J.

1976-01-01

404

An adaptive MHD method for global space weather simulations  

Microsoft Academic Search

A 3D parallel adaptive mesh refinement (AMR) scheme is described for solving the partial-differential equations governing ideal magnetohydrodynamic (MHD) flows. This new algorithm adopts a cell-centered upwind finite-volume discretization procedure and uses limited solution reconstruction, approximate Riemann solvers, and explicit multi-stage time stepping to solve the MHD equations in divergence form, providing a combination of high solution accuracy and computational

Darren L. De Zeeuw; Tamas I. Gombosi; Clinto P. T. Groth; Kenneth G. Powell; Quentin F. Stout

2000-01-01

405

MHD?driven Kinetic Dissipation in the Solar Wind and Corona  

Microsoft Academic Search

Mechanisms for the deposition of heat in the lower coronal plasma are discussed, emphasizing recent attempts to reconcile the —uid and kinetic perspectives. Structures at magnetohydrodynamic (MHD) scales may drive a nonlinear cascade, preferentially exciting high perpendicular wavenumber —uctuations. Relevant dissipative kinetic processes must be identi—ed that can absorb the associated energy —ux. The relationship between the MHD cascade and

R. J. Leamon; W. H. Matthaeus; C. W. Smith; G. P. Zank; D. J. Mullan; S. Oughton

2000-01-01

406

Note: Tangential x-ray diagnosis for investigating fast MHD events in EAST tokamak  

SciTech Connect

A tangential x-ray diagnosis has been installed in the experimental advanced superconducting tokamakvacuum vessel for the study of fast magnetohydrodynamics (MHD) events. This system is based on absolute x-ray ultraviolet detectors with a collimator which is processed by laser machine. The first experimental results have proved its ability to measure the small-scale and transient MHD perturbations.

Li Erzhong; Hu Liqun; Chen Kaiyun; Zhang Jizong; Chen Yiebin; Zhou Ruijie; Gan Kaifu; Liu Yong [Institute of Plasma Physics, Chinese Academy of Science, Hefei 230031 (China)

2010-10-15

407

Possible uses for Phillips Laboratory MHD generator. Final report, 1 October 1994-30 August 1995  

Microsoft Academic Search

There is interest in electromagnetic energy sources for applications to directed energy weapons. Candidates include portable conventional rotating machinery electric generators, magnetic flux compression generators (aka explosive generators, magnetocumulative generators or MCGs) based on explosive action, and magnetohydrodynamic (MHD) generators using chemical energy of explosives or rocket propellants. For portable high energy MHD generators, US technology base appeared to need

Turchi

1995-01-01

408

Prospects for energy recovery from plastic waste gasificators by means of MHD topping cycle  

Microsoft Academic Search

In this paper the authors present a feasibility study of a combined magnetohydrodynamic (MHD) and steam turbine plant in which the working gas is made of burnt plastic waste. The possibility of MHD retrofit of existing plant, especially fed by fossil fuel, is well known, and has been studied both for its economical and environmental benefits. The environmental impact and

A. Geri; N. Verdone; A. Salvini

1999-01-01

409

Note: Tangential x-ray diagnosis for investigating fast MHD events in EAST tokamak.  

PubMed

A tangential x-ray diagnosis has been installed in the experimental advanced superconducting tokamakvacuum vessel for the study of fast magnetohydrodynamics (MHD) events. This system is based on absolute x-ray ultraviolet detectors with a collimator which is processed by laser machine. The first experimental results have proved its ability to measure the small-scale and transient MHD perturbations. PMID:21034130

Li, Erzhong; Hu, Liqun; Chen, Kaiyun; Zhang, Jizong; Chen, Yiebin; Zhou, Ruijie; Gan, Kaifu; Liu, Yong

2010-10-01

410

Disk MHD generator study  

NASA Technical Reports Server (NTRS)

Directly-fired, separately-fired, and oxygen-augmented MHD power plants incorporating a disk geometry for the MHD generator were studied. The base parameters defined for four near-optimum-performance MHD steam power systems of various types are presented. The finally selected systems consisted of (1) two directly fired cases, one at 1920 K (2996F) preheat and the other at 1650 K (2500 F) preheat, (2) a separately-fired case where the air is preheated to the same level as the higher temperature directly-fired cases, and (3) an oxygen augmented case with the same generator inlet temperature of 2839 (4650F) as the high temperature directly-fired and separately-fired cases. Supersonic Mach numbers at the generator inlet, gas inlet swirl, and constant Hall field operation were specified based on disk generator optimization. System pressures were based on optimization of MHD net power. Supercritical reheat stream plants were used in all cases. Open and closed cycle component costs are summarized and compared.

Retallick, F. D.

1980-01-01

411

MHD processes in the outer heliosphere  

NASA Technical Reports Server (NTRS)

The magnetic field measurements from Voyager and the magnetohydrodynamic (MHD) processes in the outer heliosphere are reviewed. A bibliography of the experimental and theoretical work concerning magnetic fields and plasmas observed in the outer heliosphere is given. Emphasis in this review is on basic concepts and dynamical processes involving the magnetic field. The theory that serves to explain and unify the interplanetary magnetic field and plasma observations is magnetohydrodynamics. Basic physical processes and observations that relate directly to solutions of the MHD equations are emphasized, but obtaining solutions of this complex system of equations involves various assumptions and approximations. The spatial and temporal complexity of the outer heliosphere and some approaches for dealing with this complexity are discussed.

Burlaga, L. F.

1984-01-01

412

Coherent eigenmodes in homogeneous MHD turbulence  

NASA Astrophysics Data System (ADS)

The statistical mechanics of Fourier models of ideal, homogeneous, incompressible magnetohydrodynamic (MHD) turbulence is discussed, along with their relevance for dissipative magnetofluids. Although statistical theory predicts that Fourier coefficients of fluid velocity and magnetic field are zero-mean random variables, numerical simulations clearly show that certain coefficients have a non-zero mean value that can be very large compared to the associated standard deviation, i.e., we have coherent structure. We use eigenanalysis of the modal covariance matrices in the probability density function to explain this phenomena in terms of `broken ergodicity', which is defined to occur when dynamical behavior does not match ensemble predictions on very long time-scales. We provide examples from 2-D and 3-D magnetohydrodynamic simulations of homogeneous turbulence, and show new results from long-time simulations of MHD turbulence with and without a mean magnetic field.

Shebalin, J. V.

2010-12-01

413

Coherent Eigenmodes in Homogeneous MHD Turbulence  

NASA Technical Reports Server (NTRS)

The statistical mechanics of Fourier models of ideal, homogeneous, incompressible magnetohydrodynamic (MHD) turbulence is discussed, along with their relevance for dissipative magnetofluids. Although statistical theory predicts that Fourier coefficients of fluid velocity and magnetic field are zero-mean random variables, numerical simulations clearly show that certain coefficients have a non-zero mean value that can be very large compared to the associated standard deviation, i.e., we have coherent structure. We use eigenanalysis of the modal covariance matrices in the probability density function to explain this phenomena in terms of `broken ergodicity', which is defined to occur when dynamical behavior does not match ensemble predictions on very long time-scales. We provide examples from 2-D and 3-D magnetohydrodynamic simulations of homogeneous turbulence, and show new results from long-time simulations of MHD turbulence with and without a mean magnetic field

Shebalin, John V.

2010-01-01

414

Comparing the character of inertial range magnetohydrodynamic turbulence in the solar polar wind over the last two minima  

NASA Astrophysics Data System (ADS)

ULYSSES spacecraft solar polar passes at solar minimum provide in-situ observations of evolving MHD turbulence in the solar wind under ideal conditions of fast quiet flow. The recent unusually inactive solar minimum shows a decrease in the turbulent fluctuations of a factor of two in power in comparison with the previous minimum. We focus on two successive polar passes around the last two solar minima which provide extended intervals of quiet, fast solar wind at a range of radial distances and latitudes: the south polar pass of 1994 and the north polar pass of 1995, and the south polar pass of 2007 and the north polar pass of 2008. We perform statistical analyses of the fluctuating magnetic field observed in- situ by the ULYSSES spacecraft, from the perspective of quantitative characterization of the evolving magnetohydrodynamic (MHD) turbulence. We find a single generalized scaling function characterises this finite range turbulence and is invariant to changes in plasma conditions. If these observations are indeed characteristic of MHD turbulence evolving in- situ, then this quantifies for the first time a key aspect of the universal nature of evolving MHD turbulence in a system of finite size, with implications both for theoretical development, and for our understanding of the evolving solar wind.

Nicol, R. M.; Chapman, S. C.; Kiyani, K. H.

2009-12-01

415

ANALYTIC APPROXIMATE SEISMOLOGY OF PROPAGATING MAGNETOHYDRODYNAMIC WAVES IN THE SOLAR CORONA  

SciTech Connect

Observations show that propagating magnetohydrodynamic (MHD) waves are ubiquitous in the solar atmosphere. The technique of MHD seismology uses the wave observations combined with MHD wave theory to indirectly infer physical parameters of the solar atmospheric plasma and magnetic field. Here, we present an analytical seismological inversion scheme for propagating MHD waves. This scheme uses the observational information on wavelengths and damping lengths in a consistent manner, along with observed values of periods or phase velocities, and is based on approximate asymptotic expressions for the theoretical values of wavelengths and damping lengths. The applicability of the inversion scheme is discussed and an example is given.

Goossens, M.; Soler, R. [Centre for Mathematical Plasma Astrophysics, Department of Mathematics, KU Leuven, Celestijnenlaan 200B, B-3001 Leuven (Belgium); Arregui, I. [Instituto de Astrofisica de Canarias, Via Lactea s/n, E-38205 La Laguna, Tenerife (Spain); Terradas, J., E-mail: marcel.goossens@wis.kuleuven.be [Solar Physics Group, Departament de Fisica, Universitat de les Illes Balears, E-07122 Palma de Mallorca (Spain)

2012-12-01

416

System considerations of MHD by the utility  

SciTech Connect

Magnetohydrodynamics (MHD) is described as a promising coal technology and is now attracting increasing attention, both in the government and private sectors. This paper describes the conceptual design process that led to a configuration maximizing the chances of success of the retrofit installation. Design options such as new versus existing steam generator, gas versus steam tie-in, oxygen enrichment versus separately-fired air preheaters are discussed. 3 refs.

Griswold, J.W.; Wehrey, M.C.

1981-01-01

417

The Birth and Adolescence of MHD Turbulence  

Microsoft Academic Search

This essay provides a personal account of the development of the subject of magnetohydrodynamic (MHD) turbulence from its\\u000a birth in 1950 to its “coming-of-age” in 1971, following the development of mean-field electrodynamics, a major breakthrough\\u000a of the 1960s. The discussion covers the early ideas based on the analogy with vorticity, the passive vector problem, the suppression\\u000a of turbulence by an

Keith Moffatt

2007-01-01

418

Neutrino oscillations in MHD supernova explosions  

Microsoft Academic Search

We calculate the neutrino oscillations numerically in magnetohydrodynamic (MHD) explosion models to see how asphericity has impacts on neutrino spectra. Magneto-driven explosions are one of the most attracting scenarios for producing large scale departures from spherical symmetric geometry, that are reported by many observational data. We find that the event rates at Super-Kamiokande (SK) seen from the polar direction (e.g.,

S. Kawagoe; T. Takiwaki; K. Kotake

2010-01-01

419

Magnetohydrodynamic heat transfer in two-phase flow with temperature-dependent transport properties  

NASA Astrophysics Data System (ADS)

This paper deals with a numerical solution for the heat-transfer problem associated with the magnetohydrodynamic (MHD) Poiseuille flow of two immiscible fluids in a parallel-plate channel. The flow is assumed to be steady, one-dimensional, viscous, and electrically conducting. The present study is expected to be useful in understanding the effect of slag layers on the heat-transfer characteristics of a coal-fired MHD generator. At the high range of temperature usually found in MHD generators, the transport properties of the fluids were expected to be strong functions of temperature. In this study, the viscosity, electrical conductivity, and thermal conductivity were allowed to be power-law functions of the temperature. Both phases were assumed to be electrically conducting. The governing equations were then nonlinear, coupled, and solved numerically. An iterative scheme was developed for solving these equations, and results are presented for a wide range of parameters. In the special case of constant properties, the results are in agreement with those available in the literature.

Lohrasbi, Jahanshah

1989-06-01

420

Advected Invariants in Magnetohydrodynamics and Gas Dynamics  

NASA Astrophysics Data System (ADS)

In this paper we discuss conservation laws in ideal magnetohydrodynamics (MHD) and gas dynamics associated with advected invariants. The invariants in some cases, can be related to fluid relabelling symmetries associated with the Lagrangian map. There are different classes of invariants that are advected or Lie dragged with the flow. Simple examples are the advection of the entropy S (a 0-form), and the conservation of magnetic flux (an invariant 2-form advected with the flow). The magnetic flux conservation law is equivalent to Faraday's equation. We discuss the gauge condition required for the magnetic helicity to be advected with the flow. The conditions for the cross helicity to be an invariant are discussed. We discuss the different variants of helicity in fluid dynamics and in MHD, including: fluid kinetic helicity, cross helicity, magnetic helicity, Ertel's theorem and potential vorticity, the Hollman invariant, and the Godbillon Vey invariant for special flows for which the magnetic helicity is zero.

Webb, G. M.; Hu, Q.; McKenzie, J. F.; Dasgupta, B.; Zank, G. P.

2014-05-01

421

Magnetohydrodynamic Modeling of the Jovian Magnetosphere  

NASA Technical Reports Server (NTRS)

Under this grant we have undertaken a series of magnetohydrodynamic (MHD) simulation and data analysis studies to help better understand the configuration and dynamics of Jupiter's magnetosphere. We approached our studies of Jupiter's magnetosphere in two ways. First we carried out a number of studies using our existing MHD code. We carried out simulation studies of Jupiter s magnetospheric boundaries and their dependence on solar wind parameters, we studied the current systems which give the Jovian magnetosphere its unique configuration and we modeled the dynamics of Jupiter s magnetosphere following a northward turning of the interplanetary magnetic field (IMF). Second we worked to develop a new simulation code for studies of outer planet magnetospheres.

Walker, Raymond

2005-01-01

422

A refined similarity hypothesis for Magnetohydrodynamic turbulence  

NASA Astrophysics Data System (ADS)

Kolmogorov's refined similarity hypotheses (K62) for high-Reynolds-number hydrodynamic (HD) turbulence relate the statistics of velocity increments to the local average of energy dissipation, recognizing the intermittency of dissipation. Although not proven, these hypotheses have been widely recognized and tested in HD turbulence, and they have also been shown to hold true for other stochastic processes. In this work, we extend Kolmogorov's hypotheses to high-Reynolds-number magnetohydrodynamics (MHD) by proposing a form with mixed Elsasser variables, contrasting in this way to several prior suggestions. This extension is examined with high-resolution simulations of MHD turbulence and compared with results from hydrodynamic turbulence simulations. Implications for solar wind turbulence are discussed, including multifractal structure, relationship to the third order law, structure of the cascade, and signatures of dissipation.

Matthaeus, W. H.; Wan, M.; Osman, K.; Oughton, S.; Rappazzo, A. F.; Chhiber, R.

2011-12-01

423

Hypersonic MHD Propulsion System Integration for the Mercury Lightcraft  

SciTech Connect

Introduced herein are the design, systems integration, and performance analysis of an exotic magnetohydrodynamic (MHD) slipstream accelerator engine for a single-occupant 'Mercury' lightcraft. This ultra-energetic, laser-boosted vehicle is designed to ride a 'tractor beam' into space, transmitted from a future orbital network of satellite solar power stations. The lightcraft's airbreathing combined-cycle engine employs a rotary pulsed detonation thruster mode for lift-off and landing, and an MHD slipstream accelerator mode at hypersonic speeds. The latter engine transforms the transatmospheric acceleration path into a virtual electromagnetic 'mass-driver' channel; the hypersonic momentum exchange process (with the atmosphere) enables engine specific impulses in the range of 6000 to 16,000 seconds, and propellant mass fractions as low as 10%. The single-stage-to-orbit, highly reusable lightcraft can accelerate at 3 Gs into low Earth orbit with its throttle just barely beyond 'idle' power, or virtually 'disappear' at 30 G's and beyond. The objective of this advanced lightcraft design is to lay the technological foundations for a safe, very low cost (e.g., 1000X below chemical rockets) air and space transportation for human life in the mid-21st Century - a system that will be completely 'green' and independent of Earth's limited fossil fuel reserves.

Myrabo, L.N. [Mechanical, Aerospace, and Nuclear Engineering Dept., Rensselaer Polytechnic Institute, Troy, NY (United States); Rosa, R.J. [Department of Mechanical Engineering, Montana State University, Bozeman, MT (United States)

2004-03-30

424

On the question of hysteresis in Hall magnetohydrodynamic reconnection  

SciTech Connect

Controversy has been raised regarding the cause of hysteresis, or bistability, of solutions to the equations that govern the geometry of the reconnection region in Hall magnetohydrodynamic (MHD) systems. This brief communication presents a comparison of the frameworks within which this controversy has arisen and illustrates that the Hall MHD hysteresis originally discovered numerically by Cassak et al. [Phys. Rev. Lett. 95, 235002 (2005)] is a different phenomenon from that recently reported by Zocco et al. [Phys. Plasmas 16, 110703 (2009)] on the basis of analysis and simulations in electron MHD with finite electron inertia. We demonstrate that the analytic prediction of hysteresis in EMHD does not describe or explain the hysteresis originally reported in Hall MHD, which is shown to persist even in the absence of electron inertia.

Sullivan, Brian P.; Bhattacharjee, A.; Huang Yimin [Center for Integrated Computation and Analysis of Reconnection and Turbulence, University of New Hampshire, Space Science Center, Durham, New Hampshire 03824 (United States)

2010-11-15

425

The complete set of Casimirs in Hall-magnetohydrodynamics  

SciTech Connect

A procedure for determining all the Casimir constants of motion in magnetohydrodynamics (MHD) [E. Hameiri, Phys. Plasmas 11, 3423 (2004)] is extended to Hall-MHD. We obtain and solve differential equations for the variational derivatives of all the Casimirs, which must be satisfied for any dynamically accessible motion in Hall-MHD. In an extension of the more commonly considered Hall-MHD model, we also include the electron fluid entropy. The most interesting case for plasma confinement, which is usually true for axisymmetric configurations but desirable in general, is when both the magnetic field and the ion velocity field form the two separate families of nested toroidal surfaces. The Casimirs are then three functionals for each surface, involving the fluxes of certain vector fields and the number of particles contained in each. We also determine a family of independent Casimirs in a general configuration.

Kawazura, Yohei [Graduate School of Frontier Sciences, University of Tokyo Kashiwa, Chiba 277-8561 (Japan); Hameiri, Eliezer [Courant Institute of Mathematical Sciences, New York University, New York, New York 10012 (United States)

2012-08-15

426

Time-resolved observation of discrete and continuous magnetohydrodynamic dynamo in the reversed-field pinch edge  

SciTech Connect

We report the first experimental verification of the magnetohydrodynamic (MHD) dynamo in the reversed-field pinch (RFP). A burst of MHD dynamo electric field is observed during the sawtooth crash, followed by an increase in the local parallel current in the Madison Symmetric Totus RFP edge. By measuring each term, the parallel MHD mean-field Ohm's law is observed to hold within experimental error bars both between and during sawtooth crashes.

Ji, H.; Almagri, A.F.; Prager, S.C.; Sarff, J.S. (Department of Physics, University of Wisconsin Madison, Madison, Wisconsin 53706 (United States))

1994-08-01

427

Travel to France for presentation of paper on MHD coal combustor. Foreign trip report, September 28--October 6, 1991.  

National Technical Information Service (NTIS)

A paper entitled ''Numerical Flow Simulation in the Slogging Stage of an MHD Coal Combustor'' was presented at an international scientific conference on ''Energy Transfer in Magnetohydrodynamic Flows.'' The conference was held at the Cadaracfie Center of ...

O. P. Norton

1991-01-01

428

Broken Symmetry and Coherent Structure in MHD Turbulence  

NASA Technical Reports Server (NTRS)

Absolute equilibrium ensemble theory for ideal homogeneous magnetohydrodynamic (MHD) turbulence is fairly well developed. Theory and Simulation indicate that ideal MHD turbulence non-ergodic and contains coherent structure. The question of applicability real (i.e., dissipative) MHD turbulence is examined. Results from several very long time numerical simulations on a 64(exp 3) grid are presented. It is seen that coherent structure begins to form before decay dominates over nonlinearity. The connection with inverse spectral cascades and selective decay will also be discussed.

Shebalin, John V.

2007-01-01

429

Magnetohydrodynamics (With 87 figures)  

Microsoft Academic Search

Prelude The Sun Brief History Overall Properties The Atmosphere Solar Activity The Solar Revolution Magnetohydrodynamic Equations Flux Tubes Fundamental Equations Induction Equation The Lorentz Force Concluding Comment Magnetohydrostatics Introduction Potential Fields Force-Free Fields Magnetic Flux Tubes Magnetohydrodynamic Waves Sound Waves Alfven Waves Compressional Alfven Waves Magnetoacoustic Waves Effect of Magnetic Diffusion on Alfven Waves Shock Waves The Solar Wind Introduction

Eric R. Priest

1994-01-01

430

Coal-gasification\\/MHD\\/steam-turbine combined-cycle (GMS) power generation  

Microsoft Academic Search

Advantages of a clean fuel system are presented and include the elimination of mineral matter or slag from all components other than the coal gasifier and gas cleanup system; reduced wear and corrosion on components; and increased seed recovery resulting from reduced exposure of seed to mineral matter or slag. Efficiencies in some specific GMS power plants were shown to

J. M. Lytle; D. D. Marchant

1980-01-01

431

Magnetohydrodynamic generator scaling analysis for baseload commercial powerplants  

SciTech Connect

Magnetohydrodynamic generator channel scaling analyses have been performed to establish the effect of generator size and oxygen enrichment on channel performance. These studies have shown that MHD generator channels can be designed to operate efficiently over the range of 250 to 2135. The optimum design conditions for each of the thermal inputs were established by investigating various combinations of electrical load parameters, pressure ratios, magnetic field profiles, and channel lengths. From these parameter variations the set of conditions producing the optimum performance was selected for the design point. These results provide design flexibility for the baseload combined cycle MHD/steam powerplant.

Swallom, D.W.; Pian, C.C.P.

1983-07-01

432

A stable HLLC Riemann solver for relativistic magnetohydrodynamics  

NASA Astrophysics Data System (ADS)

In this short note we improve on an HLLC Riemann solver for relativistic magnetohydrodynamics (MHD). The improvement consists in realizing that density jumps as well as jumps in the transverse velocity can be safely incorporated into the HLLC Riemann solver for relativistic MHD. The iteration process described here is low cost, stable and fast-converging. It obviates the need to have one formulation when the longitudinal magnetic field is non-zero and another when it vanishes. Excellent operation is shown on several test problems.

Kim, Jinho; Balsara, Dinshaw S.

2014-08-01

433

Structure formation through magnetohydrodynamical instabilities in protoplanetary and accretion disks  

NASA Astrophysics Data System (ADS)

Structure formation in various astronomical systems through magnetohydrodynamical (MHD) instabilities has been investigated. The effect of magnetic field enhancement in sheared flows is studied as the eigenmode problem in a non-self-adjoint system, and new mathematical and physical aspects of the instability are shown. The mechanism for the faster structure formation in a protoplanetary disk with MHD instabilities is suggested with linear analysis and simulation. Experiments to simulate the plasmas of protoplanetary and active galactic nuclei are also suggested. The coupling of magnetic field enhancement and magnetic buoyancy has been studied and mode coupling of two instabilities are shown. The stability of nonaxisymmetric perturbations in a differentially rotating astrophysical accretion disk is analyzed by fully incorporating the properties of shear flows. The magnetorotational instability has been investigated as the most promising instability to explain anomalous angular momentum transfer in accretion disks. The apparent narrow window of the age difference of the Sun and the Earth is one of the most difficult problems in the planetary formation theory. The magnetorotational, Parker, and kinematic dynamo instabilities under the presence of magnetic fields in the protoplanetary disk can greatly facilitate the formation of density structures that may provide seeds of protoplanetesimals prior to the onset of the gravitational Jeans instability. The unstable eigenmodes with complex and pure imaginary eigenvalues without any artificial disk edge boundaries is shown to be discrete. The nonlocal behavior of eigenmodes in the vicinity of Alfvén singularities at ? D = +/-?A is investigated mathematically and physically, where ?D is the Doppler- shifted wave frequency and ?A = k?vA is the Alfvén frequency. The effects of the Parker, magnetorotational (Balbus- Hawley), and kinematic dynamo instabilities are evaluated by comparing the properties of these instabilities in protoplanetary disks. The mass spectra of aggregated density structures are calculated by the above mechanism in the radial direction for axisymmetric MHD torus equilibrium and power-law density profile models. The coupling of the magnetorotational and the Parker instabilities is studied here by three-dimensional MHD simulations. The coupling of these instabilities is analyzed linearly, and preliminary results are shown. (Abstract shortened by UMI.)

Noguchi, Koichi

2001-09-01

434

MHD--Developing New Technology to Meet the Energy Crisis  

ERIC Educational Resources Information Center

Magnetohydrodynamics is a technology that could utilize the nation's most abundant fossil fuel and produce electrical energy more efficiently and cleanly than present-day turbines. A national research and development program is ongoing in Butte, Montana at the Montana Energy and MHD Research and Development Institute (MERDI). (Author/RK)

Fitch, Sandra S.

1978-01-01

435

MHD modeling of magnetized target fusion experiments.  

SciTech Connect

Magnetized Target Fusion (MTF) is an alternate approach to controlled fusion in which a dense (0(1017-'8 cm-')), preheated (O(200 ev)), and magnetized (0( 100 kG)) target plasma is hydrodynamically compressed by an imploding liner. If electron thermal conduction losses are magnetically suppressed, relatively slow O(1 cm/microsecond) 'liner-on-plasma' compressions may be practical, using liners driven by inexpensive electrical pulsed power. Target plasmas need to remain relatively free of potentially cooling contaminants during formation and compression. Magnetohydrodynamic (MHD) calculations including detailed effects of radiation, heat conduction, and resistive field diffusion have been used to model separate target plasma (Russian MAGO, Field Reversed Configuration at Los Alamos National Laboratory) and liner implosion experiments (without plasma fill), such as recently performed at the Air Force Research Laboratory (Albuquerque). Using several different codes, proposed experiments in which such liners are used to compress such target plasmas are now being modeled in one and two dimensions. In this way, it is possible to begin to investigate important issues for the design of such proposed liner-on-plasma fusion experiments. The competing processes of implosion, heating, mixing, and cooling will determine the potential for such MTF experiments to achieve fusion conditions.

Sheehey, P. T. (Peter T.); Faehl, Rickey J.; Kirkpatrick, R. C. (Ronald C.); Lindemuth, I. R. (Irvin R.)

2001-01-01

436

MHD Generating system  

DOEpatents

According to the present invention, coal combustion gas is the primary working fluid and copper or a copper alloy is the electrodynamic fluid in the MHD generator, thereby eliminating the heat exchangers between the combustor and the liquid-metal MHD working fluids, allowing the use of a conventional coalfired steam bottoming plant, and making the plant simpler, more efficient and cheaper. In operation, the gas and liquid are combined in a mixer and the resulting two-phase mixture enters the MHD generator. The MHD generator acts as a turbine and electric generator in one unit wherein the gas expands, drives the liquid across the magnetic field and thus generates electrical power. The gas and liquid are separated, and the available energy in the gas is recovered before the gas is exhausted to the atmosphere. Where the combustion gas contains sulfur, oxygen is bubbled through a side loop to remove sulfur therefrom as a concentrated stream of sulfur dioxide. The combustor is operated substoichiometrically to control the oxide level in the copper.

Petrick, Michael (Joliet, IL); Pierson, Edward S. (Chicago, IL); Schreiner, Felix (Mokena, IL)

1980-01-01

437

SPECIAL RELATIVISTIC MAGNETOHYDRODYNAMIC SIMULATION OF A TWO-COMPONENT OUTFLOW POWERED BY MAGNETIC EXPLOSION ON COMPACT STARS  

SciTech Connect

The nonlinear dynamics of outflows driven by magnetic explosion on the surface of a compact star is investigated through special relativistic magnetohydrodynamic simulations. We adopt, as the initial equilibrium state, a spherical stellar object embedded in hydrostatic plasma which has a density {rho}(r) {proportional_to} r{sup -}{alpha} and is threaded by a dipole magnetic field. The injection of magnetic energy at the surface of a compact star breaks the equilibrium and triggers a two-component outflow. At the early evolutionary stage, the magnetic pressure increases rapidly around the stellar surface, initiating a magnetically driven outflow. A strong forward shock driven outflow is then excited. The expansion velocity of the magnetically driven outflow is characterized by the Alfven velocity on the stellar surface and follows a simple scaling relation v{sub mag} {proportional_to} v{sub A}{sup 1/2}. When the initial density profile declines steeply with radius, the strong shock is accelerated self-similarly to relativistic velocity ahead of the magnetically driven component. We find that it evolves according to a self-similar relation {Gamma}{sub sh} {proportional_to} r{sub sh}, where {Gamma}{sub sh} is the Lorentz factor of the plasma measured at the shock surface r{sub sh}. A purely hydrodynamic process would be responsible for the acceleration mechanism of the shock driven outflow. Our two-component outflow model, which is the natural outcome of the magnetic explosion, can provide a better understanding of the magnetic active phenomena on various magnetized compact stars.

Matsumoto, Jin; Asano, Eiji; Shibata, Kazunari [Kwasan and Hida Observatories, Kyoto University, Kyoto (Japan); Masada, Youhei, E-mail: jin@kusastro.kyoto-u.ac.jp [Graduate School of System Informatics, Department of Computational Science, Kobe University, Kobe (Japan)

2011-05-20

438

Reconnection events in two-dimensional Hall magnetohydrodynamic turbulence  

SciTech Connect

The statistical study of magnetic reconnection events in two-dimensional turbulence has been performed by comparing numerical simulations of magnetohydrodynamics (MHD) and Hall magnetohydrodynamics (HMHD). The analysis reveals that the Hall term plays an important role in turbulence, in which magnetic islands simultaneously reconnect in a complex way. In particular, an increase of the Hall parameter, the ratio of ion skin depth to system size, broadens the distribution of reconnection rates relative to the MHD case. Moreover, in HMHD the local geometry of the reconnection region changes, manifesting bifurcated current sheets and quadrupolar magnetic field structures in analogy to laminar studies, leading locally to faster reconnection processes in this case of reconnection embedded in turbulence. This study supports the idea that the global rate of energy dissipation is controlled by the large scale turbulence, but suggests that the distribution of the reconnection rates within the turbulent system is sensitive to the microphysics at the reconnection sites.

Donato, S.; Servidio, S.; Carbone, V. [Dipartimento di Fisica, Universita della Calabria, I-87036 Cosenza (Italy); Dmitruk, P. [Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires and Instituto de Fisica de Buenos Aires, CONICET, Buenos Aires (Argentina); Shay, M. A.; Matthaeus, W. H. [Bartol Research Institute and Department of Physics and Astronomy, University of Delaware, Newark, Delaware 19716 (United States); Cassak, P. A. [Department of Physics, West Virginia University, Morgantown, West Virginia 26506 (United States)

2012-09-15

439

Laser production and heating of plasma for MHD application  

NASA Technical Reports Server (NTRS)

Experiments have been made on the production and heating of plasmas by the absorption of laser radiation. These experiments were performed to ascertain the feasibility of using laser-produced or laser-heated plasmas as the input for a magnetohydrodynamic (MHD) generator. Such a system would have a broad application as a laser-to-electricity energy converter for space power transmission. Experiments with a 100-J-pulsed CO2 laser were conducted to investigate the breakdown of argon gas by a high-intensity laser beam, the parameters (electron density and temperature) of the plasma produced, and the formation and propagation of laser-supported detonation (LSD) waves. Experiments were also carried out using a 1-J-pulsed CO2 laser to heat the plasma produced in a shock tube. The shock-tube hydrogen plasma reached electron densities of approximately 10 to the 17th/cu cm and electron temperatures of approximately 1 eV. Absorption of the CO2 laser beam by the plasma was measured, and up to approximately 100 percent absorption was observed. Measurements with a small MHD generator showed that the energy extraction efficiency could be very large with values up to 56 percent being measured.

Jalufka, N. W.

1988-01-01

440

Laser production and heating of plasma for MHD application  

SciTech Connect

Experiments have been made on the production and heating of plasmas by the absorption of laser radiation. These experiments were performed to ascertain the feasibility of using laser-produced or laser-heated plasmas as the input for a magnetohydrodynamic (MHD) generator. Such a system would have a broad application as a laser-to-electricity energy converter for space power transmission. Experiments with a 100-J-pulsed CO/sub 2/ laser were conducted to investigate the breakdown of argon gas by a high-intensity laser beam, the parameters (electron density and temperature) of the plasma produced, and the formation and propagation of laser-supported detonation (LSD) waves. Experiments were also carried out using a 1-J-pulsed CO/sub 2/ laser to heat the plasma produced in a shock tube. The shock-tube hydrogen plasma reached electron densities of approximately 10 to the 17th/cu cm and electron temperatures of approximately 1 eV. Absorption of the CO/sub 2/ laser beam by the plasma was measured, and up to approximately 100 percent absorption was observed. Measurements with a small MHD generator showed that the energy extraction efficiency could be very large with values up to 56 percent being measured.

Jalufka, N.W.

1988-03-01

441

Efficient acceleration of relativistic magnetohydrodynamic jets  

NASA Astrophysics Data System (ADS)

Relativistic jets in active galactic nuclei, galactic microquasars, and gamma-ray bursts are widely considered to be magnetohydrodynamically driven by black hole accretion systems, although the conversion mechanism from the Poynting into the particle kinetic energy flux is still open. Recent detailed numerical and analytical studies of global structures of steady, axisymmetric magnetohydrodynamic (MHD) flows with specific boundary conditions have not reproduced as rapid an energy conversion as required by observations. In order to find more suitable boundary conditions, we focus on the flow along a poloidal magnetic field line just inside the external boundary, without treating the transfield force balance in detail. We find some examples of the poloidal field structure and corresponding external pressure profile for an efficient and rapid energy conversion as required by observations, and that the rapid acceleration requires a rapid decrease of the external pressure above the accretion disk. We also clarify the differences between the fast magnetosonic point of the MHD flow and the sonic point of the de Laval nozzle.

Toma, Kenji; Takahara, Fumio

2013-08-01

442

Solar-driven liquid metal magnetohydrodynamic generator  

NASA Technical Reports Server (NTRS)

A solar oven heated by concentrated solar radiation as the heat source of a liquid metal magnetohydrodynamic (LMMHD) power generation system is proposed. The design allows the production of electric power in space, as well as on Earth, at high rates of efficiency. Two types of the solar oven suitable for the system are discussed.

Lee, J. H.; Hohl, F.

1981-01-01

443

Solar-Driven Liquid Metal Magnetohydrodynamic Generator.  

National Technical Information Service (NTIS)

A solar oven heated by concentrated solar radiation as the heat source of a liquid metal magnetohydrodynamic (LMMHD) power generation system is proposed. The design allows the production of electric power in space, as well as on Earth, at high rates of ef...

J. H. Lee F. Hohl

1981-01-01

444

Solar-driven liquid metal magnetohydrodynamic generator  

NASA Astrophysics Data System (ADS)

A solar oven heated by concentrated solar radiation as the heat source of a liquid metal magnetohydrodynamic (LMMHD) power generation system is proposed. The design allows the production of electric power in space, as well as on Earth, at high rates of efficiency. Two types of the solar oven suitable for the system are discussed.

Lee, J. H.; Hohl, F.

1981-05-01

445

Magnetohydrodynamic modeling of the solar corona during Whole Sun Month  

Microsoft Academic Search

The Whole Sun Month campaign (August 10 to September 8, 1996) brought together a wide range of space-based and ground-based observations of the Sun and the interplanetary medium during solar minimum. The wealth of data collected provides a unique opportunity for testing coronal models. We develop a three-dimensional magnetohydrodynamic (MHD) model of the solar corona (from 1 to 30 solar

J. A. Linker; Z. Mikic; D. A. Biesecker; R. J. Forsyth; S. E. Gibson; A. J. Lazarus; A. Lecinski; P. Riley; A. Szabo; B. J. Thompson

1999-01-01

446

Proposal of Electrode Connection on Diagonal MHD Accelerator  

NASA Astrophysics Data System (ADS)

Applications of magnetohydrodynamic (MHD) accelerator for advanced propulsion has been proposed. The Magnetohydrodynamic Augmented Propulsion Experiment (MAPX) that has diagonal connected MHD accelerator is planned by NASA Marshall Space Flight Center. The diagonal accelerator with suitable electrode connections can achieve the condition that the current of flow direction is neutralized to avoid flow asymmetry and needless Joule heating. It is called the Hall current neutralized condition. In this paper, the suitable electrode connection for the neutralized condition is assessed theoretically, and it is evaluated whether the connection is able to be achieved in actual device. Although difference from ideal connection causes the difference of the current distribution, the impact is so little that variation of axial flow velocity is almost same as ideal case. We found that the actual MHD accelerator in MAPX can also attain the Hall current neutralized condition almost similar to the ideal condition.

Sakamoto, Nobuomi; Kondo, Jyunichi; Harada, Nobuhiro

447

Magnetohydrodynamics and its hazard assessment  

Microsoft Academic Search

Potential occupational and environmental hazards of a typical combined open-cycle MHD\\/steam cycle power plant are critically assessed on the basis of direct\\/indirect research information. Among the potential occupational hazards, explosion at the coal feed system or at the superconducting magnet; combustor rupture in a confined pit; high intensity dc magnetic field exposure at the channel; and combustion products leakage from

W.-T. Chan

1981-01-01

448

Prospects for Nuclear Electric Propulsion Using Closed-Cycle Magnetohydrodynamic Energy Conversion  

NASA Technical Reports Server (NTRS)

Nuclear electric propulsion (NEP) has long been recognized as a major enabling technology for scientific and human exploration of the solar system, and it may conceivably form the basis of a cost-effective space transportation system suitable for space commerce. The chief technical obstacles to realizing this vision are the development of efficient, high-power (megawatt-class) electric thrusters and the development of low specific mass (less than 1 kg/kWe) power plants. Furthermore, comprehensive system analyses of multimegawatt class NEP systems are needed in order to critically assess mission capability and cost attributes. This Technical Publication addresses some of these concerns through a systematic examination of multimegawatt space power installations in which a gas-cooled nuclear reactor is used to drive a magnetohydrodynamic (MHD) generator in a closed-loop Brayton cycle. The primary motivation for considering MHD energy conversion is the ability to transfer energy out of a gas that is simply too hot for contact with any solid material. This has several intrinsic advantages including the ability to achieve high thermal efficiency and power density and the ability to reject heat at elevated temperatures. These attributes lead to a reduction in system specific mass below that obtainable with turbine-based systems, which have definite solid temperature limits for reliable operation. Here, the results of a thermodynamic cycle analysis are placed in context with a preliminary system analysis in order to converge on a design space that optimizes performance while remaining clearly within established bounds of engineering feasibility. MHD technology issues are discussed including the conceptual design of a nonequilibrium disk generator and opportunities for exploiting neutron-induced ionization mechanisms as a means of increasing electrical conductivity and enhancing performance and reliability. The results are then used to make a cursory examination of piloted Mars missions during the 2018 opportunity.

Litchford, R. J.; Bitteker, L. J.; Jones, J. E.

2001-01-01

449

Magnetohydrodynamic method of producing electric power. Collection of articles. Number 3; Magnitogidro-dinamicheskii metod polucheniya elektroenergii. Sbornik statei. Vypusk tretii  

Microsoft Academic Search

The first section deals with the theory and calculation of MHDflows ; including edge effects in channels with metallic walls at the inlet and non-; stationary flow in a MHD-channel. Integral methods are used to calculate heat ; transfer in a MHD-channel. Insulation properties, arc behavior, electrode ; erosion, suitability of silicon carbide as an electrode material, and electrode ;

V. A. Kirillin; A. E. Sheiindlin

1972-01-01

450

Magnetohydrodynamic cellular automata  

NASA Technical Reports Server (NTRS)

A generalization of the hexagonal lattice gas model of Frisch, Hasslacher and Pomeau is shown to lead to two-dimensional magnetohydrodynamics. The method relies on the ideal point-wise conservation law for vector potential.

Montgomery, David; Doolen, Gary D.

1987-01-01

451

Magnetohydrodynamic cellular automata  

NASA Astrophysics Data System (ADS)

A generalization of the hexagonal lattice gas model of Frisch, Hasslacher and Pomeau is shown to lead to two-dimensional magnetohydrodynamics. The method relies on the ideal point-wise conservation law for vector potential.

Montgomery, David; Doolen, Gary D.

1987-02-01

452

Filamentary magnetohydrodynamic plasmas.  

National Technical Information Service (NTIS)

A filamentary construct of magnetohydrodynamical plasma dynamics, based on the Elsasser variables was developed. This approach is modeled after discrete vortex models of hydrodynamical turbulence, which cannot be expected in general to produce results ide...

R. Kinney T. Tajima N. Petviashvili J. C. McWilliams

1993-01-01

453