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1

Supersonic Magnetohydrodynamic (MHD) Power Generation System and Its Preliminary Experiment  

Microsoft Academic Search

Magneto hydrodynamic (MHD) power generation system has an important potential application in high-speed aero craft. According to the principles of MHD power generation, shock tunnel and ionization, a supersonic MHD power generation system is developed and introduced in this paper. Helium is used for driver gas and argon for driven gas. Equilibrium contact surface operating mode is selected to obtain

Tao Zhu; Yinghong Li; Yiwen Li; Bailing Zhang; Feng Chen

2012-01-01

2

Magnetohydrodynamic Power Generation.  

National Technical Information Service (NTIS)

Magnetohydrodynamic (MHD) Power Generation is a concise summary of MHD theory, history, and future trends. Results of the major international MHD research projects are discussed. Data from MHD research is included. Economics of initial and operating costs...

J. L. Smith

1984-01-01

3

Mitigation of magnetohydrodynamic electromagnetic pulse (MHD-EMP) effects from commercial electric power systems  

Microsoft Academic Search

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). This can adversely affect electrical power systems. In this report, the effects of this nuclear environment on critical facilities connected to the commercial power system are considered. Methods of mitigating the MHD-EMP impacts are

P. R. Barnes; F. M. Tesche; E. F. Vance

1992-01-01

4

Cogeneration via MagnetoHydroDynamic (MHD) Power Generator  

Microsoft Academic Search

By passing the combustion gases through magnetic field, magneto generator converts heat directly to electricity power without moving parts. The inherent characteristic of high efficiency and low emission makes Coal fired electric power generation technology attractive to be a potential alternative power generation method in the future. This article presents the working principle of MHD generator and describes the coal

Manohar Kulkarni; Xiangyang Gong

2003-01-01

5

A methodology to assess the effects of magnetohydrodynamic electromagnetic pulse (MHD-EMP) on power systems  

SciTech Connect

This paper summarizes a method to evaluate the possible effects of magnetohydrodynamic-electromagnetic pulse (MHD-EMP) on power systems. This method is based on the approach adapted to study the impact of geomagnetic storms on power systems. The paper highlights the similarities and differences between the two phenomena. Also presented are areas of concern which are anticipated from MHD-EMP on the overall system operation.

Legro, J.R.; Abi-Samra, N.C.; Crouse, J.C.; Tesche, F.M.

1986-07-01

6

Methodology to assess the effects of magnetohydrodynamic electromagnetic pulse (MHD-EMP) on power systems  

Microsoft Academic Search

This paper summarizes a method to evaluate the possible effects of magnetohydrodynamic-electromagnetic pulse (MHD-EMP) on power systems. This method is based on the approach adapted to study the impact of geomagnetic storms on power systems. The paper highlights the similarities and differences between the two phenomena. Also presented are areas of concern which are anticipated from MHD-EMP on the overall

J. R. Legro; N. C. Abi-Samra; J. C. Crouse; F. M. Tesche

1985-01-01

7

A methodology to assess the effects of magnetohydrodynamic electromagnetic pulse (MHD-EMP) on power systems  

Microsoft Academic Search

This paper summarizes a method to evaluate the possible effects of magnetohydrodynamic-electromagnetic pulse (MHD-EMP) on power systems. This method is based on the approach adapted to study the impact of geomagnetic storms on power systems. The paper highlights the similarities and differences between the two phenomena. Also presented are areas of concern which are anticipated from MHD-EMP on the overall

J. R. Legro; N. C. Abi-Samra; J. C. Crouse; F. M. Tesche

1986-01-01

8

Methodology to assess the effects of magnetohydrodynamic electromagnetic pulse (MHD-EMP) on power systems  

SciTech Connect

This paper summarizes a method to evaluate the possible effects of magnetohydrodynamic-electromagnetic pulse (MHD-EMP) on power systems. This method is based on the approach adapted to study the impact of geomagnetic storms on power systems. The paper highlights the similarities and differences between the two phenomena. Also presented are areas of concern which are anticipated from MHD-EMP on the overall system operation. 12 refs., 1 fig.

Legro, J.R.; Abi-Samra, N.C.; Crouse, J.C.; Tesche, F.M.

1985-01-01

9

Mitigation of magnetohydrodynamic electromagnetic pulse (MHD-EMP) effects from commerical electric power systems  

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). This can adversely affect electrical power systems. In this report, the effects of this nuclear environment on critical facilities connected to the commercial power system are considered. Methods of mitigating the MHD-EMP impacts are investigated, and recommended protection schemes are presented. Guidelines for testing facilities to determine the effects of MHD-EMP and to validate the mitigation methods also are discussed.

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

1992-03-01

10

Mitigation of magnetohydrodynamic electromagnetic pulse (MHD-EMP) effects from commerical electric power systems. Power Systems Technology Program  

Microsoft Academic Search

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). This can adversely affect electrical power systems. In this report, the effects of this nuclear environment on critical facilities connected to the commercial power system are considered. Methods of mitigating the MHD-EMP impacts are

P. R. Barnes; F. M. Tesche; E. F. Vance

1992-01-01

11

Mitigation of magnetohydrodynamic electromagnetic pulse (MHD-EMP) effects from commerical electric power systems. Power Systems Technology Program  

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). This can adversely affect electrical power systems. In this report, the effects of this nuclear environment on critical facilities connected to the commercial power system are considered. Methods of mitigating the MHD-EMP impacts are investigated, and recommended protection schemes are presented. Guidelines for testing facilities to determine the effects of MHD-EMP and to validate the mitigation methods also are discussed.

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

1992-03-01

12

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

Microsoft Academic Search

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

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

1981-01-01

13

Ceramic magnetohydrodynamic (MHD) micropump  

NASA Astrophysics Data System (ADS)

Magnetohydrodynamic (MHD) pumping has several attractive features including no-moving-parts operation, compatibility with biological solutions, and bi-directional pumping capability. In this work, a re-circulating ceramic MHD micropump is described. The MHD operation principle is based on the generation of Lorenz forces on ions within an electrolytic solution by means of perpendicular electric and magnetic fields. These Lorenz forces propel the ions through a channel, thus creating a net flow with no moving parts. Fabrication of the pumps is achieved by means of a new ceramic MEMS (CMEMS) platform in which devices are built from multiple layers of green-sheet ceramics. The major advantage to this technology is that unlike many other fabrication technologies, the multi-layer ceramic CMEMS platform is truly three-dimensional, thus enabling the building of complex integrated systems within a single platform. The ceramic-based MHD pumps have been analyzed and tested using both finite element modeling and experimental validation. Test results indicate that the pumps are capable of pumping a wide range of biological fluids in the flow rate range of microliters per minute. Additionally, good stability over 24 hours and good correlation with modeling data have been verified.

Sadler, Daniel J.; Changrani, Rajnish; Chou, Chia-Fu; Zindel, Daniel; Burdon, Jeremy; Zenhausern, Frederick

2001-09-01

14

Magnetohydrodynamic electromagnetic pulse (MHD-EMP) interaction with power transmission and distribution systems  

SciTech Connect

This report discusses the effects of the late-time high-altitude electromagnetic pulse (HEMP) on electrical transmission and distribution (T&D) systems. This environment, known as the magnetohydrodynamic electromagnetic pulse (MHD-EMP), is a very slowly varying electric field induced in the earth`s surface, similar to the field induced by a geomagnetic storm. It can result in the flow of a quasi-dc current in grounded power lines and in the subsequent magnetic saturation of transformers. This saturation, in turn, causes 6-Hz harmonic distortion and an increase in the reactive power required by generation facilities. This report analyzes and discusses these phenomena. The MHD-EMP environment is briefly discussed, and a simplified form of the earth-induced electric field is developed for use in a parametric study of transmission line responses. Various field coupling models are described, and calculated results for the responses of both transmission- and distribution-class power lines are presented. These calculated responses are compared with measurements of transformer operation under dc excitation to infer the MHD-EMP response of these power system components. It is found that the MHD-EMP environment would have a marked effect on a power system by inducing up to several hundreds of amperes of quasi-dc current on power lines. These currents will cause transformers to saturate which could result in excessive harmonic generation, voltage swings, and voltage suppression. The design of critical facilities which are required to operate during and after MHD-EMP events will have to be modified in order to mitigate the effects of these abnormal power system conditions.

Tesche, F.M. [Tesche (F.M.), Dallas, TX (United States); Barnes, P.R. [Oak Ridge National Lab., TN (United States); Meliopoulos, A.P.S. [Georgia Inst. of Tech., Atlanta, GA (United States). Dept. of Electrical Engineering

1992-02-01

15

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

16

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

17

MHD POWER CONVERSION  

Microsoft Academic Search

Development problems and technical features of magnetohydrodynamic (MHD) ; generators that could operate with the relatively low temperatures provided by ; gas-cooled reactors are discussed. Principles of MHD generation are given, and ; proposed designs for a 500-Mwe power plant and an MHD space power convertor are ; included. Electron injection and electron-heating ionization are the two forms ; of

W. E. Gunson; E. E. Smith; T. C. Tsu; J. H. Wright

1963-01-01

18

Magnetohydrodynamic Electromagnetic Pulse (MHD-EMP) interaction with power transmission and distribution systems  

Microsoft Academic Search

This report discusses the effects of the late-time high-altitude electromagnetic pulse (HEMP) on electrical transmission and distribution (T&D) systems. This environment, known as the magnetohydrodynamic electromagnetic pulse (MHD-EMP), is a very slowly varying electric field induced in the earth's surface, similar to the field induced by a geomagnetic storm. It can result in the flow of a quasi-dc current in

F. M. Tesche; P. R. Barnes; A. P. S. Meliopoulos

1992-01-01

19

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

NASA Astrophysics Data System (ADS)

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.

1981-09-01

20

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

21

Magnetohydrodynamics (MHD) engineering test facility (ETF) 200 mwe power plant. Design requirements document (DRD). Final report  

Microsoft Academic Search

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

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

1981-01-01

22

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

23

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

24

A new integral method for magnetohydrodynamic (MHD) flow analysis  

SciTech Connect

A new Magnetohydrodynamic (MHD) analysis and simulation model is developed to provide analysis of current MHD test data and simulation of future higher-interaction prototypical hardware at the Component Development and Integration Facility (CDIF) of the Department of Energy. The model will also be useful for design and performance prediction of larger-scale MHD components being proposed for retrofit of existing power plants and for various military applications of higher power density. An analytical approximation of the turbulent boundary-layer velocity profile was used to describe attached and near separated MHD flow over the entire computational domain. The velocity profile model was validated with available incompressible and compressible non-MHD turbulent boundary-layer flow experimental data. An analytical description of the temperature as a function of velocity, through an MHD turbulent boundary layer for constant but non-unity Pradtl number, has been derived in this study to provide a better representation of the MHD enthalpy layer profiles. An improved electrical model was coupled into the code to provide the electrical distribution throughout the flow field.

Lee Yingming.

1991-01-01

25

MHD (magnetohydrodynamics) program plan, FY 1988  

SciTech Connect

The essential elements of the current program, which are based on the June 1984 Coal-Fired MHD Preliminary Transition and Program Plan, are to: (1) develop technical and environmental data for the integrated MHD topping cycle system through long-term (1000 hours) POC testing; (2) develop technical and environmental data for the integrated MHD bottoming cycle subsystem through long-term (4000 hours) POC testing; (3) design and construct a seed regeneration system capable of independent operation, using spent seed materials from the MHD process; (4) prepare a conceptual design for an MHD retrofit plant; and (5) continue system studies and supporting research necessary for system testing. Results of the topping cycle POC tests at the Component Development and Integration Facility (CDIF), coupled with the bottoming cycle POC test results obtained at the Coal Fired Flow Facility (CFFF), and the seed regeneration POC effort will provide the critical engineering data base for the private sector's final decision on proceeding with the design, construction, and operation of an MHD retrofit. The development schedule, decision points, and resource requirements are shown in Exhibit 3. The current MHD program is directed toward base-load, both stand-alone and retrofit, coal-fired power plant application. Development of a base-load utility plant should enhance development of MHD for other utility and industrial applications. MHD may also find application in the electrical energy intensive industries. 7 figs.

Not Available

1988-04-01

26

MAGNETOHYDRODYNAMIC POWER GENERATION USING NUCLEAR FUEL. Research Report 87  

Microsoft Academic Search

A review of the basic theory of magnetohydrodynamic (MHD) power ; generators is given. The basic electrical properties of gases are reviewed. ; Over-all performance characteristics of MHD generators are presented as a ; function of these gas properties. It is pointed out that MHD shows most promise ; for applications where high power (one megawatt and up) is desired.

Rosa

1960-01-01

27

MHD power generation  

Microsoft Academic Search

In a magnetohydrodynamic (MHD) generator an electrically conducting gas replaces the rotating copper coil of the currently used electric generator. This substitution involves a principle which was recognized 150 years ago by Faraday. Development of the MHD process as an industrial method of generating electricity, however, had to wait until a better understanding of the dynamics and handling of hot

F. A. Hals; D. B. Stickler; R. Kessler; R. E. Gannon

1978-01-01

28

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

29

Magnetohydrodynamic power generation  

Microsoft Academic Search

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

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

1985-01-01

30

Simulation of a seawater MHD power generation system  

Microsoft Academic Search

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

Xiaojun Liu; Tsukasa Kiyoshi; Minoru Takeda

2006-01-01

31

MHD (Magnetohydrodynamics) Channel Slag Characterization: Final Report.  

National Technical Information Service (NTIS)

An exploratory study, supplemented by limited experimental data, is conducted to establish the influence of slag composition on the MHD channel performance. The nature of coal slag in an MHD environment is described and a comparative analysis of coal slag...

R. J. Pollina R. J. Rosa L. C. Farrar

1989-01-01

32

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

33

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

Microsoft Academic Search

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

J. L. Bates; D. D. Marchant

1986-01-01

34

MHD (magnetohydrodynamics) Program Plan, FY 1989  

SciTech Connect

The essential elements of the current program, which is a continuation of the program outlined in the FY 1988 MHD Program Plan, are to: develop technical and environmental data for the integrated MHD topping cycle system through long-term (1000 hours) POC testing; develop technical and environmental data for the integrated MHD bottoming cycle subsystem through long-term (4000 hours) POC testing; design and construct a seed regeneration system capable of independent operation, using spent seed materials from the MHD process; prepare a conceptual design for an MHD retrofit plant; and continue system studies and supporting research necessary for system testing. Results of the topping cycle POC tests at the Component Development and Integration Facility (CDIF), coupled with the bottoming cycle POC test results obtained at the Coal Fired Flow Facility (CFFF), and the seed regeneration POC effort will provide the critical engineering data base for the private sector's final decision on proceeding with the design, construction, and operation of an MHD retrofit. The development schedule, decision points, and resource requirements are discussed. As part of the MHD program, international activities of several nations are monitored and evaluated through contact with the international MHD scientific and technical community. 6 figs.

Not Available

1989-05-01

35

[Nonlinear magnetohydrodynamics]. [Threshold unstable MHD activity  

SciTech Connect

Theoretical predictions were compared with available data from JET on the threshold unstable MHD activity in toroidal confinement devices. In particular, questions arising as to Hartmans number and the selection of a kinematic viscosity are discussed.

Not Available

1992-01-01

36

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

37

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

Microsoft Academic Search

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

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

1993-01-01

38

MHD (magnetohydrodynamics) instabilities in simple plasma configuration  

SciTech Connect

This work provides what, we hope, is a relatively simple, self contained description of MHD instabilities in plasmas with simple configurations. By simple configuration, we mean a plasma in which all quantities vary in only one spatial direction. We deal with such plasmas here because we want to emphasize the basic physics of MHD instabilities. Although some fusion devices are inherently two or three dimensional in nature, there are others, specifically tokamaks and reversed field pinches which are, to good approximation, one dimensional. Also, these devices both display a wealth of complex MHD activity which can be fruitfully discussed. One deceptive aspect of MHD instabilities is that the simplest ones are extremely easy to understand. However more complicated instabilities, for instance in a plasma where both an axial and azimuthal field are present are much more difficult to visualize; but they are also much more interesting. This work is divided into two parts. Chapters 2-9 describe linear theory and chapters 10-15 describe the nonlinear theory. The latter part is naturally much more speculative than the former because less is known about nonlinear theory.

Manheimer, W.M.; Lashmore-Davies, C.

1984-01-01

39

MHD power plant characteristics  

Microsoft Academic Search

The general system features of an MHD power plant are described in terms of process requirements, MHD plant systems and components, and component performance constraints. In addition, basic thermal cycles are outlined, with special emphasis on methods of obtaining high initial temperatures, use of generator exhaust gas heat in low-temperature cycles, effect of regenerative oxidizer preheating on plant efficiency, simplification

W. E. Amend; G. N. Morozov

1978-01-01

40

Analysis of the magnetohydrodynamic flow of a fissioning gas in a disk MHD generator  

SciTech Connect

The influence of fissioning and magnetohydrodynamic (MHD) interaction on the steady, supersonic flow of a compressible, turbulent, weakly ionized, fissioning gas in an outflow disk MHD generator is investigated in this work. The two-dimensional (r,z) MHD flow is modeled using the thin-layer Navier-Stokes equations with MHD and fission power density source terms, and Maxwell's equations under the MHD Approximations and assuming negligible induced magnetic induction. The simple plasma physics models used in this work suggest that the electron number densities (O 10[sup 19]m[sup 3]) and corresponding electrical conductivity levels (O 1 S/m) obtained from fission-fragment induced ionization alone may be insufficient for practical MHD generator operation. The MHD flow equations with the fission power density source term are integrated in boundary-fitted coordinates using the explicit method of MacCormack. The equations of electromagnetics, with variable plasma physics transport properties, are solved using an Alternating-Direction-Implicit (ADI) scheme. A consistent 2-D MHD solution is obtained by iteration between the fluid solver an the electromagnetics solver. The 2-D M solution methodology is used to analyze the influence of duct geometry and fission power density (for neutron flux levels between 0 and 10[sup 17] n/cm[sup 2]s) on the behavior of internal supersonic flows (with total Mach numbers less than 3), and to characterize the effects of variable applied magnetic induction levels and generators load resistances on the spatial profiles of important generator variables. THe predictions of the 2-D MHD solver developed in this work are compared with those of a quasi-one-dimensional Euler solver with MHD an fission source terms; the agreement between the two approaches suggests that the quasi-one-dimensional Euler solver does an excellent job predicting the behavior of supersonic, fissioning, disk MHD flows.

Welch, G.E.

1992-01-01

41

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

42

Laser-powered MHD generators for space application  

Microsoft Academic Search

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.

N. W. Jalufka

1986-01-01

43

A Magnetohydrodynamic Power Panel for Space Reentry Vehicles  

Microsoft Academic Search

During reentry from space, a layer of high temperature air 3000 K is formed extend- ing tens of centimeters from the surface of the vehicle, well out into the high speed flow regime. Magnetohydrodynamics (MHD) can then be used to generate power by project- ing magnetic fields outside the vehicle into the conducting air stream and collecting the resulting current.

Haydn N. G. Wadley; Richard B. Miles; Anthony G. Evans

2007-01-01

44

Athena: Grid-Based code for astrophysical magnetohydrodynamics (MHD)  

NASA Astrophysics Data System (ADS)

Athena is a grid-based code for astrophysical magnetohydrodynamics (MHD). It was developed primarily for studies of the interstellar medium, star formation, and accretion flows. The code has been designed to be easily extensible for use with static and adaptive mesh refinement. It combines higher-order Godunov methods with the constrained transport (CT) technique to enforce the divergence-free constraint on the magnetic field. Discretization is based on cell-centered volume-averages for mass, momentum, and energy, and face-centered area-averages for the magnetic field. Novel features of the algorithm include (1) a consistent framework for computing the time- and edge-averaged electric fields used by CT to evolve the magnetic field from the time- and area-averaged Godunov fluxes, (2) the extension to MHD of spatial reconstruction schemes that involve a dimensionally-split time advance, and (3) the extension to MHD of two different dimensionally-unsplit integration methods. Implementation of the algorithm in both C and Fortran95 is detailed, including strategies for parallelization using domain decomposition. Results from a test suite which includes problems in one-, two-, and three-dimensions for both hydrodynamics and MHD are given, not only to demonstrate the fidelity of the algorithms, but also to enable comparisons to other methods. The source code is freely available for download on the web.

Stone, James M.; Gardiner, Thomas A.; Teuben, Peter; Hawley, John F.; Simon, Jacob B.

2010-10-01

45

Low pellet gain and high efficiency icf power plant model by MHD power generation  

Microsoft Academic Search

We propose a low pellet gain and high efficiency inertial confinement fusion (ICF) power generation system using a magnetohydrodynamic (MHD) power generation, and employ analytical comparative studies for power generation system options. When the thermal output at high temperature (about 2000–2400K) can be extracted from a fusion reactor, only an MHD generator can be used and can convert efficiently ICF

Takashi Kikuchi; Nob. Harada

2000-01-01

46

MHD Power Generation  

Microsoft Academic Search

The MHD Generator is now widely recognized as one of the more promising new methods for large-scale electric power generation. Its primary function, in the terminology of thermodynamics, is that of an ``expansion engine'' like the reciprocating piston engine and the turbine; and although premature, it is tempting to suppose that it represents the next and perhaps the ultimate step

A. Kantrowitz; R. J. Rosa

1974-01-01

47

The application of liquid-metal MHD (magnetohydrodynamics) to renewable energy sources. [Liquid metal MHD  

Microsoft Academic Search

A system study of the OMACON liquid-metal MHD conversion technology was undertaken for SCE to define the potential gains that could be derived from the use of the technology in selected utility applications. Four applications studied were: (1) the solar power tower; (2) a medium temperature solar system employing line focus collectors; (3) geothermal power systems; and (4) an Integrated

G. F. Berry; M. Petrick; E. S. Pierson; S. Sukoriansky

1987-01-01

48

Oxygen-enriched air production for MHD power plants  

SciTech Connect

Direct coal-fired MHD/steam power plants using preheated, oxygen-enriched air offer the near-term potential of attractive power plant efficiencies, operating flexibility, and improved reliability compared to plants with separately-fired or directly-heated air preheaters. Systems analyses of various MHD/steam power plants indicate that maximum plant efficiency is achieved by directly preheating combustion air with high temperature combustion products from the MHD topping cycle. However, difficulties in developing regenerative preheater materials to continuously withstand the corrosive, erosive, and fouling action of hot potassium and slag-laden gases preclude the use of directly-heated high temperature air preheaters in first generation MHD plants. Previously, high power consumption for oxygen production has limited the consideration of oxygen enrichment for MHD application. Therefore, the Magnetohydrodynamics Division of the Department of Energy (DOE/MHD) requested Gilbert Associates, Inc. (GAI) to develop and then analyze information on minimum power requirements and plant costs for oxygen production for a range of oxygen enrichments and delivery pressures. Such information will facilitate evaluation of oxygen-enriched MHD system performance and economics. An analysis of several of the cryogenic air separation process cycle variations and compression schemes that have been 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. (WHK)

Not Available

1980-05-01

49

Investigation of the Characteristics of MHD Power Generation by a Corona Jet Across a Magnetic Field  

Microsoft Academic Search

In a common magnetohydrodynamic (MHD) power generation, the plasma is produced by equilibrium thermal ionization with working temperatures over 2000 K, and it is difficult to select wall materials that will withstand these high temperatures. The authors present the case that using the low-temperature corona jet produced by nonequilibrium gas discharge can lower the temperature in the MHD electrical power

Xinliang Wang; Dan Ye; Fan Gu

2008-01-01

50

Non-Equilibrium Plasma MHD Electrical Power Generation at Tokyo Tech  

Microsoft Academic Search

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

T. Murakami; Y. Okuno; H. Yamasaki

2008-01-01

51

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

52

Particulate sampling methods used at the University of Tennessee Space Institute's coal fired magnetohydrodynamic (MHD) facility  

Microsoft Academic Search

The University of Tennessee Space Institute (UTSI), operates a coal-fired magnetohydrodynamic (MHD) research facility with downstream components capable of simulating a steam bottoming plant with particulate control devices. The major downstream components of the coal fired flow facility (CFFF) include a superheater test module (SHTM); an air heater; and three parallel particulate control devices, a baghouse, electrostatic precipitator (ESP), and

1988-01-01

53

Development of a diffuser/nozzle-type micropump based on magnetohydrodynamic (MHD) principle  

NASA Astrophysics Data System (ADS)

This paper reports a research effort to microfabricate a nozzle-diffuser type of micropumps based on the magnetohydrodynamic (MHD) principle using LIGA technologies. The micropump is driven using the Lorentz force and can be used to deliver electrically conductive fluids. The major advantage of a MHD-based micropump is that it does not contain any moving parts. It may have potential applications in medicine delivery, biological and biomedical studies. Prototypes of MHD micropumps have been fabricated and tested. Significant bubble generation was observed due to electrolysis effect. These bubbles made the flow two-phase one and resulted in flow rate reduction. To overcome bubble generation, a new generation of MHD micropumps is currently under development. This new, diffuser/nozzle type of the MHD micropumps is based on the similar design as widely used in the diffuser/nozzle pumps with diaphragm.

Heng, Khee-Hang; Huang, Lei; Wang, Wanjun; Murphy, Michael C.

1999-08-01

54

Lumped-parameter model for a micropump based on the magnetohydrodynamic (MHD) principle  

NASA Astrophysics Data System (ADS)

This paper reports a lumped-parameter mathematical model for a magnetohydrodynamic (MHD) micropump being developed by the authors. The micropump can be used to deliver electrically conductive fluids. The major advantage of a MHD based micropump is that it does not contain any moving parts. It may have potential applications in medicine delivery, biological and biomedical studies. To develop a design guideline for the MHD micropump, it is desired that the dynamic behavior of the flow in a microsystem driven with MHD body force. A bond graph model has been developed for the MHD micropump. A commercial software, 20 SIM, was used as the simulation tools. The simulation results for two different sizes of micropumps with a 1 percent salt-water solution used as a pumping fluid are presented in the paper.

Huang, Lei; Wang, Wanjun; Murphy, Michael C.

1999-03-01

55

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

56

Rf-assisted magnetohydrodynamic power generation in a pure-argon plasma  

SciTech Connect

We describe seed-free pure-argon-plasma magnetohydrodynamic (MHD) power generation assisted by an external radio-frequency electromagnetic field to enhance the nonequilibrium plasma excitation process. The rf heating induces nonequilibrium ionization under a low total argon-gas temperature at which thermal ionization is insufficient. The rf-assisted plasma, the behavior of which is rather stable, contributes to continuous MHD energy conversion.

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

2005-04-25

57

Rf-assisted magnetohydrodynamic power generation in a pure-argon plasma  

NASA Astrophysics Data System (ADS)

We describe seed-free pure-argon-plasma magnetohydrodynamic (MHD) power generation assisted by an external radio-frequency electromagnetic field to enhance the nonequilibrium plasma excitation process. The rf heating induces nonequilibrium ionization under a low total argon-gas temperature at which thermal ionization is insufficient. The rf-assisted plasma, the behavior of which is rather stable, contributes to continuous MHD energy conversion.

Murakami, Tomoyuki; Okuno, Yoshihiro; Yamasaki, Hiroyuki

2005-04-01

58

Rf-assisted magnetohydrodynamic power generation in a pure-argon plasma  

Microsoft Academic Search

We describe seed-free pure-argon-plasma magnetohydrodynamic (MHD) power generation assisted by an external radio-frequency electromagnetic field to enhance the nonequilibrium plasma excitation process. The rf heating induces nonequilibrium ionization under a low total argon-gas temperature at which thermal ionization is insufficient. The rf-assisted plasma, the behavior of which is rather stable, contributes to continuous MHD energy conversion.

Tomoyuki Murakami; Yoshihiro Okuno; Hiroyuki Yamasaki

2005-01-01

59

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

60

The application of liquid-metal MHD (magnetohydrodynamics) to renewable energy sources. [Liquid metal MHD  

SciTech Connect

A system study of the OMACON liquid-metal MHD conversion technology was undertaken for SCE to define the potential gains that could be derived from the use of the technology in selected utility applications. Four applications studied were: (1) the solar power tower; (2) a medium temperature solar system employing line focus collectors; (3) geothermal power systems; and (4) an Integrated Coal-Gasifier Combined Cycle plant. Computer simulations were developed for each of the system applications and used to calculate thermodynamic performance; the computer simulations were also used to evaluate sensitivity of system performance to key component efficiencies and operating parameters. The computer simulations accounted for all known first-order loss mechanisms. Only the solar power tower and geothermal power system are presented in this paper.

Berry, G.F.; Petrick, M.; Pierson, E.S.; Sukoriansky, S.

1987-01-01

61

Investigation of rocket-powered, open-cycle, magnetohydrodynamic generators for high, pulsed power needs in space. Master's thesis  

Microsoft Academic Search

This investigation examined the possibility of using a rocket-powered magnetohydrodynamic generator for pulse power in space of 300 megawatts (MW). The result is a preliminary design of an MHD generator using an open cycle disk channel and a single superconducting solenoid coil. The disk channel acts as a thrust deflector, and internal vanes counteract induced vorticity. The use of a

1986-01-01

62

Plasma opening switch. A system and structure analysis in the framework of the Hall MHD [pulsed power  

Microsoft Academic Search

Power flow in a plasma opening switch device is analyzed in the framework of the Hall magnetohydrodynamics. Previously, an attempt to provide scaling laws for conduction and opening times was performed. The present work mainly concerns the Hall MHD treatment of the opening phase, when both fast electron magnetohydrodynamics magnetic field evolution and the ion motion are incorporated. Obtained results

A. S. Chuvatin; L. I. Rudakov; B. Etlicher

1997-01-01

63

Space power installation based on solar radiation collector and MHD generator  

Microsoft Academic Search

A megawatt-class space power installation based on a mirror solar radiation collector and an magnetohydrodynamic (MHD) generator is considered. Probable decisions for the construction of a mirror system and a radiation heat receiver are proposed. The analysis of mass characteristics shows that the level of specific power of 600 W\\/kg can be reached. An MHD generator with nonuniform gas-plasma flow,

V. S. Slavin; G. C. Bakos; T. A. Milovidova; K. A. Finnikov

2006-01-01

64

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.

65

Superconducting magnets for an MHD test facility and base load power plant  

Microsoft Academic Search

The development of Magnetohydrodynamic (MHD) power generation in the U.S. may involve the construction of an Engineering Test Facility (ETF) as a step toward a base load or full-scale power plant. This paper describes the superconducting magnet requirements for the ETF and base load plants and gives the results to date in a program involving production of magnet reference designs

Z. Stekly; R. Thome; W. Punchard

1977-01-01

66

Comparison of SS-GIC and MHD-EMP-GIC effects on power systems  

Microsoft Academic Search

A comparative study of the effects of solar storm geomagnetically induced currents (SS-GIC) and nuclear detonation geomagnetically induced currents (magnetohydrodynamic electromagnetic pulse GIC or MHD-EMP-GIC) on the power system. The earth surface electric field of the MHD electromagnetic pulse is given to be on the order of 100 V\\/km, with a duration up to several minutes; and the electric field

A. P. S. Meliopoulos; E. N. Glytsis; G. J. Cokkinides; M. Rabinowitz

1994-01-01

67

Studies on Low Specific Mass NFR\\/MHD Power Generation System for Space Applications  

Microsoft Academic Search

The aim of this study is to examine a magnetohydrodynamic (MHD) power generation system for the space applications using a nuclear fission reactor as the heat source. This MHD system uses He\\/Xe mixed gas as coolant instead of alkali-metal-seeded inert gas. The interrelation between the specific heat of the coolant and the mass flow rate was examined. When the specific

Le Chi Kien; Nobuhiro Harada

2006-01-01

68

Analysis and design of an ultra-high-temperature, hydrogen-fueled MHD generator as an open cycle power supply  

Microsoft Academic Search

The theoretical analysis of a partially-ionized hydrogen gas flow (gas temperatures of approximately 10,000 to 20,000 K) through a particular class of magnetohydrodynamic (MHD) generators and the preliminary design of these MHD generators as open cycle, electric power supplies are performed. Analysis of the gas flow through these ultra-high temperature MHD generators requires a coupled gas dynamics\\/radiative heat transfer solution.

Jeffrey P. Moder

1990-01-01

69

Investigation of two-phase liquid-metal magnetohydrodynamic power systems  

Microsoft Academic Search

Liquid metal magnetohydrodynamic (LMMHD) power systems are low-temperature devices with operating temperatures which are determined by the thermodynamic and physical properties of the fluids. A description is presented of an experimental program which is to provide a basic understanding of the two-phase flow in a magnetic field. Cycle studies show that the two-phase liquid-metal MHD power cycle has excellent potential

W. E. Amend; G. Fabris; J. Cutting

1976-01-01

70

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

71

Substorm features in MHD (magnetohydrodynamics) simulations of magnetotail dynamics  

SciTech Connect

We present a review and extended analysis of characteristic results from our nonideal three-dimensional MHD simulations of unstable magnetotail evolution, which develops without the necessity of external driving or prescribed localization on nonideal effects. These modes involve magnetic reconnection at a near-Earth site in the tail, consistent with the near-Earth neutral line model of substorms. The evolution tailward of the reconnection site is characterized by plasmoid formation and ejection into the far tail, plasma sheet thinning between the near-Earth neutral line (X line) and the departing plasmoid, and fast tailward flow, which occupies large sections of the plasma sheet at larger distance from the X line, while it occurs only in very limited space and time sections close to the X line. The region earthward of the X line is characterized by dipolarization, propagating from midnight toward the flank regions and, perhaps, tailward. It is associated with the signatures of the substorm current wedge: reduction and diversion of cross-tail current from a region surrounding the reconnection site and increase of Region 1 type field-aligned currents. A mapping of these currents to the Earth on the basis of an empirical magnetic field model shows good agreement of the mapped current system with the observed Region 1 field-aligned current system and its substorm associated changes, including also a nightward and equatorward shift of the peaks of the field-aligned current density. The evolution of the mappings of the boundaries of the closed field line region bears strong resemblance to the formation and expansion of he auroral bulge. The consistency of all of these details with observed substorm features strongly supports the idea that substorm evolution in the tail is that of a large scale nonideal instability.

Birn, J.; Hesse, M.

1990-01-01

72

Method and apparatus for producing electrical power and for the simultaneous heating of fluid, utilizing a magnetohydrodynamic generator  

Microsoft Academic Search

There is provided a method and an apparatus for producing electrical power and for the simultaneous heating of fluid by means of a magnetohydrodynamic (MHD) generator. The method comprises providing a heating means for heating a mixture of liquid metal and an organic liquid to form a two-phase liquid metal-vapor flow, directing the two-phase liquid metal-vapor through a MHD-generator to

Branover

1983-01-01

73

Utility views of MHD power generation  

Microsoft Academic Search

Economic and ecological advantages of developing an open-cycle MHD process for generating electric power from MHD combustion of coal, without the use of turbines, rotating generators, or other moving parts absorbing energy, are discussed and listed explicitly. Higher efficiencies, low cost of electric power generated, far more manageable pollution problems, 50% less warm water effluents, inertialess startup and shutdown, reduced

C. H. Shih; M. K. Guha

1977-01-01

74

THE PROSPECTS OF MHD POWER GENERATION  

Microsoft Academic Search

The prospects for magnetohydrcdynamic (MHD) pcwer generation range from ; a small, short-duty-cycle unit for space applications to a large power station ; for commercial use. The gaseous MHD generator appears at first glance to have ; some outstanding advantages over the conventional turbogenerators in both ; stationary and auxiliary power applications. Appropriately high gas conductivity ; and reliable flow-containment

L. Steg; G. W. Sutton

1960-01-01

75

Gas Core Reactor with Magnetohydrodynamic Power System and Cascading Power Cycle  

SciTech Connect

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 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 thousands of megawatt fission power acts as the heat source for a high-temperature MHD power converter. A uranium tetrafluoride fuel mix, with {approx}95% mol fraction helium gas, provides a stable working fluid for the primary MHD Brayton cycle. The hot working fluid exiting a topping cycle MHD generator has sufficient heat to drive a conventional helium Brayton cycle with 35% thermal efficiency as well as a superheated steam Rankine cycle, with up to 40% efficiency, which recovers the waste heat from the intermediate Brayton cycle. A combined cycle efficiency of close to 70% can be achieved with only a modest MHD topping cycle efficiency. The high-temperature direct-energy conversion capability of an MHD dynamo combined with an already sophisticated steam-powered turbine industry knowledge base allows the cascading cycle design to achieve breakthrough 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 established high-temperature gas-cooled reactors and high-temperature molten salt core reactors have pioneered. However, the GCR-MHD concept has considerable promise; for example, like molten salt reactors the fuel is continuously cycled, allowing high burnup, continuous burning of actinides, and hence greatly improved fuel utilization. The fuel inventory is two orders of magnitude lower than LWRs of comparable power output, and fissile plutonium production is likewise lower than in spent LWR fuel. Besides these features, specific GCR-MHD design challenges such as fission enhanced gas conductivity of the MHD partially ionized gas, GCR safety issues and related engineering problems are discussed.

Smith, Blair M.; Anghaie, Samim [University of Florida (United States)

2004-03-15

76

A numerical simulation model for the study of magnetohydrodynamic (MHD) waves in a structured medium  

NASA Astrophysics Data System (ADS)

This dissertation contains two basic parts: a formal development of a numerical simulation model for the study of magnetohydrodynamic (MHD) waves in a structured medium, and an application of the model to the investigation of the propagation of MHD waves in a magnetic slab and their interactions with non-magnetic surroundings. The numerical model is a time-dependent, two-dimensional, and nonlinear MHD model with gravity and radiative energy loss. The corresponding numerical code is based on the newly developed SINIL (Semi-Implicit-Non-Iterative-Lagrangian) scheme. The MHD governing equations are discretized on a Lagrangian rid, using the control-volume method. The gas dynamic properties are solved explicitly, and the magnetic field is solved implicitly without using numerical iterations. Using this numerical model, three kinds of slab waves are studied, namely, kink type slab waves, sausage type slab waves, and kink type single interface waves (which are considered as kink type slab waves in the limit of infinite slab width). In the present study, external acoustic waves can only be excited by internal body waves. The excitation of external acoustic waves represents the energy leakage from the internal magnetized region to the external field-free region. The condition of the excitation is the relative compressibility (the ratio of the internal body wave speed to the external sound speed) being greater than one.

Xiao, Yingcai

77

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

78

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

79

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

80

Oxygen Enrichment for Open Cycle Magnetohydrodynamic Power Systems.  

National Technical Information Service (NTIS)

Efficient coal fired, open cycle MHD power generation systems require a combustion flame temperature of approximately 4600 F to provide adequate electrical conductivity in the MHD gas. To achieve this high flame temperature, either highly preheated combus...

1979-01-01

81

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

Microsoft Academic Search

In order to achieve the desired efficiency in the magnetohydrodynamic (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

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

1993-01-01

82

Analysis and Design of AN UltraHigh Hydrogen-Fueled MHD Generator as AN Open Cycle Power Supply  

Microsoft Academic Search

The theoretical analysis of a partially-ionized hydrogen gas flow (gas temperatures ~10,000 -20,000 K) through a particular class of magnetohydrodynamic (MHD) generators and the preliminary design of these MHD generators as open cycle, electric power supplies are performed. Such potentially lightweight, compact and efficient power supplies may enable supersonic and hypersonic flight speeds for several beamed-energy airbreathing propulsion concepts. Analysis

Jeffrey P. Moder

1990-01-01

83

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

84

The application of liquid-metal MHD (magnetohydrodynamics) to renewable energy sources  

Microsoft Academic Search

A system study of the OMACON liquid-metal MHD conversion technology was undertaken for SCE to define the potential gains that could be derived from the use of the technology in selected utility applications. Four applications studied were: (1) the solar power tower; (2) a medium temperature solar system employing line focus collectors; (3) geothermal power systems; and (4) an Integrated

G. F. Berry; M. Petrick; E. S. Pierson; S. Sukoriansky

1987-01-01

85

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

86

Magnetohydrodynamic energy for electric power generation  

Microsoft Academic Search

Aspects of Soviet MHD development are considered along with details concerning open-cycle and closed-cycle MHD studies conducted by American companies. Liquid-metal MHD studies performed by American companies are also discussed, taking into account the selection of parametric study points, the study parameters, the LM-MHD\\/steam binary cycle configuration, assumptions, methodology, the results of a parametric study, cost methodology, MHD duct and

R. F. Grundy

1978-01-01

87

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

88

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

89

Promising fuels for MHD power stations  

Microsoft Academic Search

The influence of hydrocarbon fuel characteristics on the properties of the plasma generated in an open-cycle magnetohydrodynamic power station is examined in order to investigate the feasibility and efficiency of various fuels. Plasma electrical conductivity was determined from plasma pressure and temperature, fuel hydrocarbon ratio, oxidant oxygen content and potassium carbonate seed concentration in the combustion chamber, as a function

N. A. Kruzhilin; A. G. Rotinov; S. A. Tager; I. T. Iakubov

1979-01-01

90

High-temperature coal-syngas plasma characteristics for advanced MHD power generation  

SciTech Connect

Properties of magnetohydrodynamic (MHD) plasma based on syngas (CO, H{sub 2}) combustion products were investigated experimentally with shock tube facility. The experiments were carried out under various MHD generator load and shock tube operation conditions. Important characteristics of syngas plasma such as temperature, electric field, conductivity, and total output power were directly measured and evaluated. Special attention was paid to the influence of syngas composition (CO : H{sub 2} : O{sub 2} ratio). The results show that syngas combustion can provide high plasma ionization and attainable plasma electrical conductivity has an order of 60-80 S/m at gas temperature 3100-3300 K.

Mikheev, A.V.; Kayukawa, N.; Okinaka, N.; Kamada, Y.; Yatsu, S. [Hokkaido University, Hokkaido (Japan)

2006-03-15

91

Design for an MHD power plant as a prime mover for a Naval Vessel  

SciTech Connect

A Magnetohydrodynamic Power Plant, designed to be the prime mover for a Naval Vessel, is presented. The system is an open cycle, fossil fueled, subsonic MHD Faraday generator with directly fired air preheaters. A superconducting electric transmission drives the propellers and a standard naval steam plant is used as a bottoming cycle. The increased overall efficiency achievable with this plant allows a lighter, smaller volume ship to accommodate the same payload and reduces the overall fuel cost of the vessel.

Paluszek, M.A.

1981-01-01

92

Study to assess the effects of magnetohydrodynamic electromagnetic pulse on electric power systems. Phase I, final report. Volume 3  

SciTech Connect

In addition to the initial transients designated as fast transient high-altitude EMP (HEMP) and intermediate time EMP, electromagnetic signals are also perceived at times from seconds to hundreds of seconds after a high-altitude nuclear burst. This signal has been defined by the term magnetohydrodynamic-electromagnetic pulse (MHD-EMP). The MHD-EMP phenomena has been both detected in actual weapon tests and predicted from theoretical models. This volume documents a preliminary research effort to investigate the nature and coupling of the MHD-EMP environments to electric power systems, define the construction of approximate system response network models, and document the development of a unified methodology to assess equipment and systematic vulnerability. The MHD-EMP environment is compared to a qualitatively similar natural event, the electromagnetic environment produced by geomagnetic storms.

Legro, J.R.; Abi-Samra, N.C.; Tesche, F.M.

1985-05-01

93

Status report on MHD electrical power generation–IAEA\\/ENEA International Liaison Group on MHD Electrical power generation  

Microsoft Academic Search

The present status of commercial large-scale MHD electrical power generation is reviewed in the light of information presented at the Third International Symposium on MHD Electrical Power Generation (Salzburg, 1966) and of subsequent developments. Research and development activities, and the state of evaluation of engineering and economic factors are assessed in respect of open-cycle MHD power plant, closed-cycle MHD power

B. C. Lindley

1967-01-01

94

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

95

Diagnostic development and support of MHD (magnetohydrodynamics) test facilities: Technical progress report for the period April, May, June 1986  

Microsoft Academic Search

Mississippi State University is developing diagnostic instruments for MHD power train data acquisition and for support of MHD component development test facilities. Microprocessor-controlled optical instruments 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 MHD Energy Center computers. Additionally,

W. S. Shepard; R. L. Cook

1986-01-01

96

Prospects of MHD power generation in India using coal  

Microsoft Academic Search

The paper briefly reviews the Indian coal-based MHD power generation program. Program planning includes studies of plasma properties and plasma dynamics; development and testing of high temperature materials; testing of MHD components and subsystems; and investigation of the technical and economic aspects of MHD power cycles.

V. R. Ramaprasad; V. R. Malghan; K. Ravi Kumar

1979-01-01

97

Refractory materials for coal fueled mhd power generation. Final report  

Microsoft Academic Search

Research studies to develop improved materials for the preheater and MHD duct for a coal-fired MHD power generator used as a topping unit on a central station power plant are reported. More efficient methods of energy conversion require high temperatures which in turn necessitate better corrosion and erosive resistant materials for use in the MHD duct as electrodes and insulators.

Ure; R. W. Jr

1976-01-01

98

Non-Equilibrium Plasma MHD Electrical Power Generation at Tokyo Tech  

SciTech Connect

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. [Tokyo Institute of Technology 4259-G3-38, Nagatsuta, Midori-ku, Yokohama 226-8502 (Japan)

2008-02-21

99

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

100

The application of liquid-metal MHD (magnetohydrodynamics) to renewable energy sources  

NASA Astrophysics Data System (ADS)

A system study of the OMACON liquid-metal MHD conversion technology was undertaken for SCE to define the potential gains that could be derived from the use of the technology in selected utility applications. Four applications studied were: (1) the solar power tower; (2) a medium temperature solar system employing line focus collectors; (3) geothermal power systems; and (4) an Integrated Coal-Gasifier Combined Cycle plant. Computer simulations were developed for each of the system applications and used to calculate thermodynamic performance; the computer simulations were also used to evaluate sensitivity of system performance to key component efficiencies and operating parameters. The computer simulations accounted for all known first-order loss mechanisms. Only the solar power tower and geothermal power system are presented in this paper.

Berry, G. F.; Petrick, M.; Pierson, E. S.; Sukoriansky, S.

101

Numerical modeling of power generation from high-speed flows. I. Development of a nonequilibrium magnetohydrodynamics code  

NASA Astrophysics Data System (ADS)

The time-dependent, 2[1/2]-dimensional, axisymmetric, magnetohydrodynamics (MHD) solver, MACH2 has been upgraded to include the effects of nonequilibrium air chemistry in order to properly model weakly ionized flows over high-speed vehicles. The thermochemical model was subjected to several validation cases such as 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. Furthermore, the magnetic induction equation has been upgraded with new verified models that compute the Hall effect, ion slip terms, and an applied axial electric field. Finally, simulations of an idealized MHD electrical power generator are compared with existing analytic solutions, demonstrating the applicability of the improved numerical code to model, analyze and design MHD power generators onboard high-speed vehicles.

Lorzel, Heath; Mikellides, Pavlos G.

2011-05-01

102

MHD performance demonstration experiment, FY 1974 to FY 1984  

Microsoft Academic Search

A national program for the development of commercial, open-cycle, magnetohydrodynamic (MHD) power generation is described. The emphasis of that national program was, and is, on establishing the engineering feasibilty of using coal to fuel the MHD power system. In order to establish feasibility it was necessary to experimentally demonstrate that an MHD generator system simulating a commercial-sized device can convert

G. L. Whitehead; L. S. Christensen; R. J. Felderman

1984-01-01

103

MHD (Magnetohydrodynamic) Flow Tailoring in First Wall Coolant Channels of Self-Cooled Blankets.  

National Technical Information Service (NTIS)

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 hydr...

B. F. Picologlou C. R. Reed T. Q. Hua L. Barleon H. Kreuzinger

1988-01-01

104

UV-LIGA microfabrication and test of an ac-type micropump based on the magnetohydrodynamic (MHD) principle  

NASA Astrophysics Data System (ADS)

This paper reports on a research effort to design, microfabricate and test an AC-type magnetohydrodynamic (MHD) micropump using UV-LIGA microfabrication. The micropump is driven using the Lorentz force and can be used to deliver electrically conductive fluids. In the AC-type MHD micropump developed in our laboratory, a diffuser/nozzle is integrated with a MHD driving chamber. With a magnetic field supplied by an external permanent magnet, and an AC electrical current supplied across two copper side-walls, the distributed body force generated will produce a pressure difference on the fluid in the pumping chamber. The directional dependence of the flow resistance of the diffuser/nozzle allows for a net output flow in response to the oscillating pressure generated by the sinusoidal current. The major advantage of a MHD-based micropump is that it does not contain any moving parts. It may have potential applications in medicine delivery, and biological or biomedical studies. An AC-driven micropump may be used to improve on the performance obtained in tests of a DC-driven prototype micropump, that showed pumping performance was significantly degraded by bubble generation.

Heng, Khee-Hang; Wang, Wanjun; Murphy, Michael C.; Lian, Kun

2000-08-01

105

Magnetohydrodynamic projects at the CDIF  

SciTech Connect

The Component Development and Integration Facility (CDIF) is a major U.S. Department of Energy magnetohydrodynamics (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 second quarter of FY92, a second external water leak on the iron-core magnet was repaired, and MHD testing was completed on February 11; this was the final testing of the workhorse hardware. Workhorse hardware was removed, and installation of the proof-of-concept (POC) combustor began.

Not Available

1992-01-01

106

Magnetohydrodynamic projects at the CDIF  

SciTech Connect

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 fourth quarter of FY91, MHD testing was shut down. In addition to installing the new Data Acquisition System (DAS), activities such as rebuilding the channel, investigating and repairing the magnet leak, installing the slag removal system, and modifying existing systems were addressed.

Not Available

1991-01-01

107

Magnetohydrodynamic projects at the CDIF  

SciTech Connect

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.

Not Available

1991-01-01

108

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

109

Investigation of rocket-powered, open-cycle, magnetohydrodynamic generators for high, pulsed power needs in space. Master's thesis  

SciTech Connect

This investigation examined the possibility of using a rocket-powered magnetohydrodynamic generator for pulse power in space of 300 megawatts (MW). The result is a preliminary design of an MHD generator using an open cycle disk channel and a single superconducting solenoid coil. The disk channel acts as a thrust deflector, and internal vanes counteract induced vorticity. The use of a solid-fuel-wafer grain design rocket motor is proposed for increased electrical conductivity and pulse operation of the generator. Using conservative parameters, a generator design capable of being carried on one or two space-shuttle launches is developed with estimated mass of 24,450 kg and estimated power output of 1346 MW. The nominal operation time before refurbishment is 115 seconds; the restriction operation time is deterioration of the channel throat. This design exceeds present nuclear and solar-cell power systems in power output per unit mass.

Power, J.W.

1986-11-01

110

Airborne MHD Generator Development.  

National Technical Information Service (NTIS)

The objective of this contract was to establish the performance of a lightweight magnetohydrodynamic (MHD) power system. In pursuance of this goal a heat-sink multi-segmented 45 degree diagonal wall power channel was designed, fabricated and thermally tes...

T. A. Pape

1970-01-01

111

Effect of external fluctuation on nonequilibrium MHD power generation  

Microsoft Academic Search

The effects of externally induced small fluctuations in the input thermal energy and\\/or the seed fraction are examined using numerical simulations based on two-temperature MHD (magnetohydrodynamic) equation system. A quasi-one-dimensional approach is adopted for a disk generator. A generator with a high enthalpy extraction rate is considered, and its design parameters are set so that the full ionization of seed

S. Kabashima

1988-01-01

112

Radiation-driven MHD systems for space applications  

NASA Astrophysics Data System (ADS)

High-power radiation such as concentrated solar or high-power laser radiation is considered as a driver for magnetohydrodynamic (MHD) systems which could be developed for efficient power generation and propulsion in space. Eight different systems are conceivable since the MHD systems can be classified in two: plasma and liquid-metal MHD's. Each of these systems is reviewed and solar- (or laser-) driven MHD thrusters are proposed.

Lee, J. H.; Jalufka, N. W.

113

Diagnostic development and support of MHD (magnetohydrodynamics) test facilities: Technical progress report for the period April, May, June 1985  

Microsoft Academic Search

Mississippi State University is developing diagnostic instruments for MHD power train data acquisition and for support of MHD component development test facilities. Microprocessor-controlled optical instruments, initially developed for 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

Shepard

1985-01-01

114

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

115

Power facility with a built-in multipolar MHD generator  

SciTech Connect

The scheme of a power facility with a built-in multipolar MHD generator is discussed. In most papers devoted to airborne high-power MHD generators (self-contained or built into the nozzle of the propulsion unit), MHD channels are discussed that are based on a two-pole scheme. The processes of energy conversion in these MHD generators are usually accompanied by disturbances of flow in the entire channel volume, which, in many cases, is undesirable for the operation of power facilities. Depending on the number of pairs of poles, the proposed facility makes it possible to accomplish MHD conversion both in the nozzle peripheral zone and in the central part of the flow. An analysis of the methods and results of calculations of volume MHD effects for finite Hall parameters {beta} and MHD-interaction s, as well as of the output characteristics of multipolar MHD generators equipped with electrode modules of different types are given. A comparison of the theoretical and experimental data is made. A scheme involving an advanced propulsion unit fired with cryogenic fuel H{sub 2}+O{sub 2} and a built-in multipolar MHD generator is considered. The problems of using built-in multipolar MHD generators in propulsion units utilizing other fuel pairs are discussed.

Kovalev, K.L.; Markina, T.A. [Moscow Aviation Institute, Moscow (Russian Federation)

1995-05-01

116

On the potential for direct or MHD conversion of power from a novel plasma source to electricity for microdistributed power applications  

Microsoft Academic Search

The generation of electricity using direct electrostatic and magnetohydrodynamic (MHD) conversion of the plasma-particle energy of small to midsize chemically assisted microwave or glow discharge plasma (CA-plasma) power sources in the range of a few hundred Watts to several tens of kilowatts for microdistributed commercial applications (e.g., household, automotive, light industry, and space-based power) is studied for the first time.

Robert M. Mayo; Randall L. Mills; M. Nansteel

2002-01-01

117

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

Microsoft Academic Search

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

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

1988-01-01

118

MODELING OF MHD POWER GENERATION ON BOARD REENTRY VEHICLES  

Microsoft Academic Search

The possibility of MHD power generation on board of reentry vehicles is theoretically explored. The focus is on the ability to extract large amounts of electric power, at least several hundred kilowatts from square meter of the surface. Estimates of electrical conductivity in unseeded and alkali-seeded air and MHD performance, taking into account Hall and ion slip effects, are followed

Sergey O. Macheret; Mikhail N. Shneider; Graham V. Candler

119

MHD (Magnetohydrodynamics) Integrated Topping Cycle Project: Second quarterly technical progress report, November 1, 1987--January 31, 1988  

SciTech Connect

The overall objective of the project is to design and construct prototypical hardware for an integrated MHD topping cycle, and conduct long duration proof-of-concept tests of the integrated system at the US DOE Component Development and Integration Facility in Butte, Montana. The results of the long duration tests will augment the existing engineering design data base on MHD power train reliability, availability, maintainability, and performance, and will serve as a basis for scaling up the topping cycle design to the next level of development, an early commercial scale power plant retrofit. Progress results towards the design, fabrication and testing of the components of the MHD power train are reported. 1 fig.

Not Available

1989-01-01

120

Studies on Low Specific Mass NFR/MHD Power Generation System for Space Applications  

NASA Astrophysics Data System (ADS)

The aim of this study is to examine a magnetohydrodynamic (MHD) power generation system for the space applications using a nuclear fission reactor as the heat source. This MHD system uses He/Xe mixed gas as coolant instead of alkali-metal-seeded inert gas. The interrelation between the specific heat of the coolant and the mass flow rate was examined. When the specific heat decreases due to increase of the Xe fraction, the mass flow rate must increase to keep the output power and plant efficiency constant. A regenerator efficiency of 100% and reactor output temperature of 1800 K or higher should be chosen for the highest plant efficiency of 56% and lowest specific mass of 1.4 kg/kW. This highest plant efficiency and lowest specific mass were also expected by optimizing parameters for enthalpy extraction and radiator temperature. This means achieving high plant efficiency or low specific mass gives different values for enthalpy extraction and radiator temperature. With a higher net electrical output power, lower specific mass is obtained. This explains why the present space MHD power generation system is better than other conventional space power generation systems for the high MW-range output power.

Kien, Le Chi; Harada, Nobuhiro

121

Production of MHD Fluid.  

National Technical Information Service (NTIS)

The patent application concerns hot gaseous fluid of low ash content, suitable for use in open-cycle MHD (magnetohydrodynamic) power generation. It is produced by means of a three-stage process comprising (1) partial combustion of a hydrocarbon fuel to pr...

J. J. Lacey R. C. Kurtzrock D. Bienstock

1973-01-01

122

Production of MHD Fluid.  

National Technical Information Service (NTIS)

The patent application is on a hot gaseous fluid of low ash content, which is suitable for use in open-cycle MHD (magnetohydrodynamic) power generation. It is produced by means of a three-stage process comprising: (1) partial combustion of a hydrocarbon f...

J. J. Lacey R. C. Kurtzrock D. Bienstock

1974-01-01

123

Eighth International Conference on MHD Electrical Power Generation. Volume 1.  

National Technical Information Service (NTIS)

The proceedings of the VIIIth International Conference on MHD Electrical Power Generation contain the results of most recent R and D work aimed at practical realization of this advanced method of electrical power generation. The papers presented to the Co...

1983-01-01

124

MHD (magnetohydrodynamics) channel development: Quarterly report for January 1987-March 1987  

SciTech Connect

During the report period several slag doping tests were performed. Four of these tests are described in this report. The results were generally encouraging. Four dopants were investigated: Fe/sub 2/O/sub 3/, Fe/sub 3/O/sub 4/, MnO, and CrO/sub 2/. All but the CrO/sub 2/ proved effective within some range of dopant flow rate. At flow rates above or below this range none of the dopants were desirable. The proper ranges for each of the dopants was coarsely mapped in these experiments. When the dopants were injected directly on the anode wall a power increase was observed. This indicates a possible reduction in the voltage drop due to the presence of the dopant. No power gain or loss was observed when the dopant was injected on the cathode wall. However, inter-cathode voltages were observed to spread more uniformly along the wall. High voltages decreased and low voltages increased. This result should help to reduce wear on the cathodes and their neighboring wall elements by reducing the local electrical field. Current control circuits were tested on both MK VI and MK VII type generators and components for consolidation circuits ordered. Solutions to waste disposal problems created by the implementation of new environmental regulations are being investigated. The MHD generator data from the CDIF 87-SEED-1, 87-SEED-2, and 87-SEED-3 tests have been analyzed and the results are presented in this report. The results of the SIDA model presented in this quarterly report are obtained by assuming a constant boundary layer voltage drop. Variations in the boundary layer voltage drop as a result of diagonal loading changes, iron oxide addition, or seeding rates changes were not considered. Corrections for the effects of ..delta..V/sub b1/ will be made to the results of SIDA when the voltage drop measurements become available.

Not Available

1987-04-01

125

First demonstration of MHD power generation using externally ionized, cold, supersonic air as a working fluid  

Microsoft Academic Search

Magnetohydrodynamic (MHD) interactions present a tantalizing opportunity to control hypersonic flows without the need for strong shock waves, high entropy gain, and movable control surfaces. An MHD interaction, however, requires a conductive flowfield. At Mach numbers too low for thermal ionization, flow energies may still be sufficient to justify the cost of an efficient external ionization scheme. In this work,

Robert C. Murray

2006-01-01

126

Comparison between Yohkoh soft x-ray images and 3D MHD simulations of solar emerging flux regions. [MHD (Magnetohydrodynamic)  

SciTech Connect

The soft X-ray telescope on the Yohkoh mission enabled us to observe the evolution of emerging flux regions (EFR) in coronal X-rays with high spatial and temportal resolution. Futhermore, we now have enough computing capability to perform three-dimensional MHD simulation of EFRs with sufficient spacial resolution to study details of the flux emergence process. These new tools provide the opportunity to investigate the physics involved in the formation of coronal loops in much more detail. We carried out 3D MHD simulations of emerging magnetic flux regions under various initial conditions; (1) a horizontal magnetic flux sheet, (2) a bundle of horizontal flux tubes, and (3) a flux sheet with sheared magnetic fields. Numerical results show that coronal magnetic loops are formed due to the enhanced bouyancy resulting from gas precipitating along magnetic field lines. The interchange modes help to produce a fine fibrous structure perpendicular to the magnetic field direction in the linear stage, while the undular modes determine the overall loop structure. We observe in 3D simulations that during the ascendance of loops the bundle of flux tubes, or even the flux sheet, developes into dense filaments pinched between magnetic loops. We also find that magnetic field lines are twisted by the vortex motion produced by the horizontal expansion of magnetic loops. Our numerical results may explain the observed signatures such as (1) the spacial relation between soft X-ray loops and H[alpha] arch filaments obtained by coordinated observation between Yohkoh and ground-based observatories (Kawai et al. 1992), (2) the rate of increase in size of soft X-ray loops in EFRs (Ishido et al. 1992), (3) emergence of twisted magnetic loops, and (4) the threshold flux for formation of chromospheric arch filament systems (AFS).

Matsumoto, R.; Tajima, T.; Kaisig, M.; Shibata, K.; Ishido, Y.; Tsuneta, S.; Kawai, G; Kurokawa, H.; Akioka, M.; Acton, L.; Strong, K.; Nitta, N.

1992-01-01

127

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

128

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

129

Application of Liquid-Metal MHD (Magnetohydrodynamics) to Renewable Energy Sources.  

National Technical Information Service (NTIS)

A system study of the OMACON liquid-metal MHD conversion technology was undertaken for SCE to define the potential gains that could be derived from the use of the technology in selected utility applications. Four applications studied were: (1) the solar p...

G. F. Berry M. Petrick E. S. Pierson S. Sukoriansky

1987-01-01

130

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

131

Method and apparatus for producing electrical power and for the simultaneous heating of fluid, utilizing a magnetohydrodynamic generator  

SciTech Connect

There is provided a method and an apparatus for producing electrical power and for the simultaneous heating of fluid by means of a magnetohydrodynamic (MHD) generator. The method comprises providing a heating means for heating a mixture of liquid metal and an organic liquid to form a two-phase liquid metal-vapor flow, directing the two-phase liquid metal-vapor through a MHD-generator to generate electricity, condensing the vapor phase from the two-phase liquid metal-vapor to form liquid metal carrying organic liquid droplets, and recycling the metal and organic liquid droplets to be reheated by the heating means. The mhd apparatus comprises a closed duct system containing a mixture of liquid metal and an organic liquid, a heating means for heating the mixture in the closed system, a mhd-generator, located along the flow path of a two-phase liquid metal-vapor flow formed by the heated mixture, means for condensing the twophase flow to form a single phase flow of metal liquid containing organic liquid droplets, and means for propelling the singlephase flow to be reheated by the heating means.

Branover, H.

1983-04-26

132

A nonvariational code for calculating three-dimensional MHD (magnetohydrodynamic) equilibria  

SciTech Connect

Details are presented of the PIES code, which uses a nonvariational algorithm for calculating fully three-dimensional MHD equilibria. The MHD equilibrium equations are directly iterated in special coordinates to find self-consistent currents and magnetic fields for given pressure and current profiles and for a given outermost magnetic surface. Three important advantages of this approach over previous methods are the ease with which net current profiles can be imposed, the explicit treatment of resonances, and the ability to handle magnetic islands and stochastic field lines. The convergence properties of the code are studied for several axisymmetric and nonaxisymmetric finite-..beta.. equilibria that have magnetic surfaces. 36 refs., 14 figs., 3 tabs.

Greenside, H.S.; Reiman, A.H.; Salas, A.

1987-09-01

133

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

134

Study of Some Recent Advances in the Concept and Design of MHD Generators.  

National Technical Information Service (NTIS)

Direct conversion of energy using a high temperature working fluid makes magnetohydrodynamics (MHD) power plants potentially much more efficient than steam power stations. The study indicated an overall efficiency of 50 percent to 60 percent. This compare...

M. Vakilian

1976-01-01

135

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

136

Experimental determination of the MHD-EMP effects on power distribution transformers  

SciTech Connect

It is a well-established fact that geomagnetic storms influence electrical power transmission and distribution systems. Previous cases of such storms in the northern latitudes have resulted in occasional power disruptions, and in some cases, damage to transformers. These effects are caused by a time variation of the earth's magnetic field creating an induced electric field along the surface of the earth. This E-field acts as a voltage source along long power transmission or distribution lines, and if the line is connected to the earth at both ends, a quasi-dc current can flow. This current can cause unwanted saturation in the magnetic cores of transformers in the power system, and this, in turn produces harmonic distortion and transformer heating. This can lead to system upset (shutdown) and possibly transformer burn-out. The detonation of a high altitude nuclear explosion is also known to affect the magnetosphere, producing late-time variations of the earth's magnetic field for several hundreds of seconds. Known as the magnetohydrodynamic electromagnetic pulse (MHD-EMP), or E{sub 3}, this environment is of particular concern to electrical power systems in the event of a nuclear attack. Although the MHD-EMP induced currents can be significantly larger in magnitude, they last for a shorter period of time than do those from a geomagnetic storm. The effect of this environment compounds the adverse effects of the early-time high altitude EMP (HEMP) environment, posing a potentially serious threat to the electrical system. The present paper documents an experimental program designed to better understand the behavior of distribution-class transformers subjected to quasi-dc current excitation. Given the knowledge of the MHD-EMP-induced current flowing in a long power line, and the transformer response characteristics obtained in this program, it will be possible to make more accurate assessments of the behavior of the overall power system to EMP. 7 refs., 5 figs.

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

1991-01-01

137

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

138

Comparison of SS-GIC and MHD-EMP-GIC effects on power systems  

SciTech Connect

A comparative study of the effects of solar storm geomagnetically induced currents (SS-GIC) and nuclear detonation geomagnetically induced currents (magnetohydrodynamic electromagnetic pulse GIC or MHD-EMP-GIC) on the power system. The earth surface electric field of the MHD electromagnetic pulse is given to be on the order of 100 V/km, with a duration up to several minutes; and the electric field of the solar storms is on the order of 10 V/km, and lasts from several minutes to one hour. Both phenomena cause flow of almost direct current in the windings of power transformers through the grounding system. For long transmission lines, i.e. 300 miles or longer, this DC current offsets the 60 Hz AC and many saturate transformer cores, with secondary results such as high magnetization currents, increased harmonics, and concomitant effect on power system operation. The level of the transformer core saturation depends on the time constant of the saturation process, and on the duration and magnitude of the direct current through the transformer windings. Thus, although the solar storm effects on the power system are greater due to their much longer duration. This paper presents a technique for the computation of the induced and/or transferred voltages and currents to an electric power system from geomagnetic disturbances. For this purpose, models of transmission lines which explicitly represent grounding, earth potential, and frequency dependent phenomena, and power transformers which explicit representation of nonlinear magnetization characteristics, are utilized. Using this technique, a parametric analysis of saturation time constants is performed and the effects of MHD-EMP and SS-GIC are compared.

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

1994-01-01

139

Liquid-Metal Mhd Power Conversion for Space Electric Systems.  

National Technical Information Service (NTIS)

A number of LMMHD (Liquid Metal Magneto-Hydro-Dynamic) Power Conversion Systems (PCS) were conceived for SES (Space Electric Systems) applications. Variations of a single-stage PCS operating on the Wet Vapor Cycle can meet demands of most continuous mode ...

L. Blumenau H. Branover A. El-boher E. Spero S. Sukoriansky

1987-01-01

140

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

141

MHD (magnetohydrodynamic) thermal hydraulic analysis of three-dimensional liquid metal flows in fusion blanket ducts  

SciTech Connect

Magnetohydrodynamic flows of liquid metals in thin conducting ducts of various geometries 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. At walls parallel to the magnetic field lines, as at the side walls of a rectangular duct, the boundary layers (side layers) carry a significant fraction of the volumetric flow rate in the form of high velocity jets. The presence of these jets strongly enhances heat transfer performance. In addition, heat transfer can be further improved by guiding the flow toward a heated wall by proper variation of wall thicknesses, duct cross sectional dimensions and/or shape. Flows in nonconducting circular ducts are also examined. Experimental results obtained from the ALEX experiments at the Argonne National Laboratory are used to validate the numerical predictions. 6 refs., 7 figs.

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

1988-02-01

142

MHD mixed convection flow of a power law nanofluid over a vertical stretching sheet with radiation effect  

NASA Astrophysics Data System (ADS)

A similarity solution of the steady magnetohydrodynamic (MHD) mixed convection boundary layer flow due to a stretching vertical heated sheet in a power law nanofluid with thermal radiation effect is theoretically studied. The governing system of partial differential equations is first transformed into a system of ordinary differential equations. The transformed equations are solved numerically using the shooting method. The influence of pertinent parameters such as the nanoparticle volume fraction parameter, the magnetic parameter, the buoyancy or mixed convection parameter and the radiation parameter on the flow and heat transfer characteristics is discussed. Comparisons with published results are also presented.

Aini Mat, Nor Azian; Arifin, Norihan Md.; Nazar, Roslinda; Ismail, Fudziah; Bachok, Norfifah

2013-09-01

143

High power MHD system: Facility status and magnet test results  

Microsoft Academic Search

AEDC has been requested by the Aero Propulsion Laboratory to design, fabricate, and install facility hardware necessary to conduct tests to demonstrate the performance of high power MHD generator systems developed by AFWAL contractors. This report summarizes the AEDC effort since program inception, describes the facility under development, gives the status of each major facility component, and summarizes the results

G. L. Whitehead

1982-01-01

144

A Theoretical Study of MHD Power Generation, (II)  

Microsoft Academic Search

The electric potential drop near the electrode surfaces in MHD power generators is studied theoretically by considering a simple model, in which the current flows in the direction normal to the electrode surfaces. In order to simplify the situation so as to permit analytic solution, the idea of a “boundary layer” near the electrodes is introduced, and the problem is

Itaru MICHIYOSHI; Kunihiko UEMATSU; Masahiro NUMANO

1964-01-01

145

A Theoretical Study of MHD Power Generational, (III)  

Microsoft Academic Search

This paper deals with the lift of the electron temperature in the electromagnetic field. In view of the small ionization degree in the working gas of MHD power generation, the collision of charged particles with each other is assumed to be negligible. Under this assumption the differential equations to determine the collective behavior of electrons in the electromagnetic field were

Itaru MICHIYOSHI; Masahiro NUMANO

1965-01-01

146

Boundary layer phenomena in combustion-driven MHD power generators  

Microsoft Academic Search

An analytic and experimental study of boundary layer phenomena in combustion-driven MHD power generators has been conducted. Measurements of heat transfer rates and velocity, temperature, and electron number density profiles were compared with numerical calculations. The analysis is based on the two-dimensional boundary layer equations. The velocity, temperature, and electron number density profiles were measured at the downstream end of

J. W. Daily

1975-01-01

147

Space nuclear-MHD generator for gigawatt-level power  

NASA Astrophysics Data System (ADS)

This paper presents a closed-cycle nuclear-MHD plant providing GWe-level power output in the SPRINT mode at a power density of about 10 kWe/kg. The power supply system consists of a nuclear gas core reactor with external moderator, a contracting-expanding nozzle, an MHD generator, and a diffuser, along with supporting systems to close the cycle. The working fluid is a metal vapor with a uranium additive. The reactor core temperature is above 5000 K and reactor walls are cooled by vaporized liquid metal. The gas temperature at the MHD channel exit is about 1600 K, rising to 1800 to 1900 K after recovery in the diffuser to meet material and weight requirements for the radiator. The electrical conductivity is enhanced by fission product ionization, thermionic emission of uranium droplets, and elevated electron temperature due to electric current heating. A mathematical model of the space nuclear-MHD plant is developed, and parametric feasibility and sensitivity analyses are provided.

Goodman, Julius; Maya, I.; Williams, J. R.; Koester, John K.

148

Study to assess the effects of magnetohydrodynamic electromagnetic pulse on electric power systems, phase 1, volume 3  

Microsoft Academic Search

In addition to the initial transients designated as fast transient high-altitude EMP (HEMP) and intermediate time EMP, electromagnetic signals are also perceived at times from seconds to hundreds of seconds after a high-altitude nuclear burst. This signal was defined by the term magnetohydrodynamic-electromagnetic pulse (MHD-EMP). The MHD-EMP phenomena was detected in actual weapon tests and predicted from theoretical models. A

J. R. Legro; N. C. Abi-Samra; F. M. Tesche

1985-01-01

149

Study to assess the effects of magnetohydrodynamic electromagnetic pulse on electric power systems. Phase I, final report. Volume 3  

Microsoft Academic Search

In addition to the initial transients designated as fast transient high-altitude EMP (HEMP) and intermediate time EMP, electromagnetic signals are also perceived at times from seconds to hundreds of seconds after a high-altitude nuclear burst. This signal has been defined by the term magnetohydrodynamic-electromagnetic pulse (MHD-EMP). The MHD-EMP phenomena has been both detected in actual weapon tests and predicted from

J. R. Legro; N. C. Abi-Samra; F. M. Tesche

1985-01-01

150

Magnetohydrodynamic energy conversion by using convexly divergent channel  

SciTech Connect

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

2009-12-21

151

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

Microsoft Academic Search

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

P. J. Staiger; G. R. Seikel

1981-01-01

152

Heat transfer problem associated with an MHD power generation system - An overview  

Microsoft Academic Search

Research in the field of MHD has advanced to the point where the development of an operational system is feasible. The primary system being considered by ERDA is an open-cycle MHD\\/steam cycle power loop. Critical thermal problems impact the system due to hot ionized plasma, seed injection, slag deposition and high temperature air heaters. MHD power generation has entered the

A. W. Postlethwaite; M. M. Sluyter

1977-01-01

153

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

154

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

155

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.

1982-07-20

156

Magnetohydrodynamic power generation. Final report, March 9, 1984March 8, 1985  

Microsoft Academic Search

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

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

1985-01-01

157

Study of the Processes Resulting from the Use of Alkaline Seed in Natural Gas-Fired MHD Facilities.  

National Technical Information Service (NTIS)

Various ways of ionizing seed injection and recovery, applicable to open-cycle magnetohydrodynamic (MHD) power generation facilities, operating on sulfur-free gaseous fossil fuel, are discussed and experimentally verified. The physical and chemical change...

M. A. Styrikovich I. L. Mostinskii

1977-01-01

158

Gas-side corrosion performance of superheater/ITAH tube alloys in MHD tests with high sulfur coal.  

National Technical Information Service (NTIS)

Corrosion data have been obtained for tubes exposed for 600, 1500, and 2000 hours in a proof-of-concept magnetohydrodynamics (MHD) power generation test facility (the CFFF) to conditions representative of superheater and intermediate temperature air heate...

M. White

1993-01-01

159

Fluctuation of Power Output Due to Instability in Closed Cycle MHD Power Generation  

Microsoft Academic Search

The fluctuating output power has been measured for a disk-type MHD generator with a FUJI-1 closed-cycle MHD power generation facility. The fluctuation shows random properties which are associated with the ionization instability of the plasma in the generator. The random properties of the output power can be explained by a Poisson process. The experimental results have been ensured by a

Eliko Shimizu; Yukio Yoshikawa; Shigeharu Kabashima

1987-01-01

160

Government Research and Development Summaries: Magnetohydrodynamic Project Briefs. Irregular  

SciTech Connect

Magnetohydrodynamic Project Briefs describe the status of all R and D programs submitted to the Power Information Center by the government sponsors in energy conversion involving the magnetohydrodynamic (MHD) interaction between electromagnetic fields and electrically conducting fields, including fuels, materials, plasma dynamics, and combustion. The document is not to be reproduced, in whole or in part, for dissemination outside your own organization nor may it be reproduced for advertising or sales promotion purposes.

Not Available

1992-01-01

161

Government research and development summaries: Magnetohydrodynamic Project Briefs. Irregular  

SciTech Connect

Magnetohydrodynamic Project Briefs describe the status of all R and D programs submitted to the Power Information Center by the government sponsors in energy conversion involving the magnetohydrodynamic (MHD) interaction between electromagnetic fields and electrically conducting fields, including fuels, materials, plasma dynamics, and combustion. The document is not to be reproduced, in whole or in part, for dissemination outside your own organization nor may it be reproduced for advertising or sales promotion purposes.

Not Available

1991-01-01

162

Government research and development summaries: Magnetohydrodynamic project briefs. Irregular  

SciTech Connect

Magnetohydrodynamic Project Briefs describe the status of all R and D programs submitted to the Power Information Center by the government sponsors in energy conversion involving the magnetohydrodynamic (MHD) interaction between electromagnetic fields and electrically conducting fields, including fuels, materials, plasma dynamics, and combustion. The document is not to be reproduced, in whole or in part, for dissemination outside your own organization nor may it be reproduced for advertising or sales promotion purposes.

Not Available

1994-01-01

163

Government research and development summaries: Magnetohydrodynamic project briefs. Irregular  

SciTech Connect

Magnetohydrodynamic Project Briefs describe the status of all R and D programs submitted to the Power Information Center by the government sponsors in energy conversion involving the magnetohydrodynamic (MHD) interaction between electromagnetic fields and electrically conducting fields, including fuels, materials, plasma dynamics, and combustion. The document is not to be reproduced, in whole or in part, for dissemination outside your own organization nor may it be reproduced for advertising or sales promotion purposes.

NONE

1995-03-01

164

Government research and development summaries: Magnetohydrodynamic project briefs. Irregular  

SciTech Connect

Magnetohydrodynamic Project Briefs describe the status of all R and D programs submitted to the Power Information Center by the government sponsors in energy conversion involving the magnetohydrodynamic (MHD) interaction between electromagnetic fields and electrically conducting fields, including fuels, materials, plasma dynamics, and combustion. The document is not to be reproduced, in whole or in part, for dissemination outside your own organization nor may it be reproduced for advertising or sales promotion purposes.

Not Available

1993-01-01

165

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

166

MHD Flow Control and Power Generation in Low-Temperature Supersonic Flows.  

National Technical Information Service (NTIS)

Report developed under STTR contract for topic AFO5-T016. Results of cold MHD flow deceleration and MHD power-generation experiments conducted at The Ohio State University are presented. MHD effect on the flow is detected from flow static-pressure measure...

S. P. Gogineni I. V. Adamovich

2006-01-01

167

MHD Flow Control and Power Generation in Low-Temperature Supersonic Flows  

Microsoft Academic Search

The paper presents results of cold MHD flow deceleration and MHD power generation experiments using repetitively pulsed, short pulse duration, high voltage discharge to produce ionization in M=3 nitrogen and air flows. MHD effect on the flow is detected from the flow static pressure measurements. Retarding Lorentz force applied to the flow produces a static pressure increase of up to

Igor Adamovich; Munetake Nishihara

2006-01-01

168

Outlook for binary power plants using liquid-metal MHD  

Microsoft Academic Search

Preliminary testing and extrapolations thereof indicate that liquid-metal MHD can be used as a topping cycle to increase the efficiency of large central-station power plants. Because maximum temperatures as low as 870° C are effective, such binary plants are possible with existing material technology. The best present choices appear to be a potassium working fluid and either a (helium-or sodium-cooled)

L. L. Prem; W. E. Parkins

1970-01-01

169

Advanced fusion MHD power conversion using the CFAR cycle concept  

Microsoft Academic Search

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

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

1989-01-01

170

Investigation of direct coal-fired MHD power generation  

Microsoft Academic Search

Various experiments were carried out in a direct coal-fired MHD power generation facility. It was found that the generator's overall performance is not affected by the presence of coal slag in the generator channel. However, the erosion\\/corrosion is greatly reduced by the slag. Seed\\/slag interaction investigation showed that at 1300 K, up to 90% of potassium can be easily recovered

J. B. Dicks; K. E. Tempelmeyer; Y. C. L. Wu; L. W. Crawford

1976-01-01

171

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

172

Conceptual Design of a Coal-Fired MHD (Magnetohydrodynamics) Retrofit Plant (Scholz Plant, Sneads, FL): Volume 2. Drawings.  

National Technical Information Service (NTIS)

The US DOE/PETC is funding a conceptual design study to evaluate a coal-fired MHD retrofit plant of sufficient size to demonstrate the technical and economic viability of an MHD system operating within and electric utility environment. Westinghouse Advanc...

1989-01-01

173

Een Nieuw Model voor Het Verband Tussen Het Geleidingsvermogen en de Stroom in een MHD (Magnetohydrodynamic) Generator (A New Model for the Relation Between Conductivity and Current in an MHD (Magnetohydrodynamic) Generator).  

National Technical Information Service (NTIS)

A model for the calculation of the induced current in an MHD generator was derived. Starting from voltage probe measurements, relations between conductivity and current, and voltage drop and current were derived and inserted in the Kirchhof law. For certa...

J. C. W. Sars

1984-01-01

174

The Hydra Magnetohydrodynamics Package  

Microsoft Academic Search

The Magnetohydrodynamics package of the ALE radiation-hydrodynamics code Hydra is being extended to model the magnetic field and its effect on temperature for ICF targets. The current package capabilities include a fully three-dimensional resistive MHD package in the small Hall limit. An operator split method is used to couple the MHD to the hydrodynamics and is fully implicit in time

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

2009-01-01

175

Design Philosophy for a 3.5 MW DC to AC Converter in the CDIF MHD Test Facility  

Microsoft Academic Search

The Component Design and Integration Facility (CDIF) located in Butte, Montana, is intended to provide the means for developmental testing of various components of a Magnetohydrodynamic (MHD) generating plant. As part of this process, small scale systems will produce power which is to be fed into the Montana Power Company system for some time periods. Since the MHD generator produces

P. Wood; P. E. Pityk; F. O. Johnson; R. B. Schainker

1981-01-01

176

Experimental Performance of a Hall Magnetohydrodynamic Electric Power Generator.  

National Technical Information Service (NTIS)

A test program was conducted on a Hall Magnetohydrodynamic generator. The internal dimensions of the generator channel diverged from 4 in. in height at the channel inlet to 6 in. in height at the channel exit, and the width was 2 in. along the 48-in. leng...

R. J. LeBoeuf J. D. McNeese

1967-01-01

177

Plasma plume MHD power generator and method  

Microsoft Academic Search

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.

1993-01-01

178

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

179

Study of the MHD (Magnetohydrodynamics) Activity of a Tokamak Plasma in the Lower Hybrid Frequency Wave Current Generating Regime.  

National Technical Information Service (NTIS)

Confinement by noninductive currents was investigated in experiments on MHD instability in a tokamak plasma. The change of dependence of plasma current density and resistivity as a function of electron temperature (parameters which govern the evolution of...

J. C. Vallet

1986-01-01

180

Liquid metal magnetohydrodynamic (LMMHD) converter for space power system  

NASA Astrophysics Data System (ADS)

The liquid metal MHD or (Faraday) Converter is a conversion system which allows the production of electricity from thermal energy without any moving solid part. Then, such a system is very attractive in space where a long lifetime is required. The basic principle of the process is the expansion of a gas to accelerate a high-temperature liquid metal in an MHD generator where this liquid metal interacts with a magnetic field to produce electricity. By using an inductive generator the electric current can be delivered directly on the alternative form with adjustable voltage and frequency.

Alemany, A.; Marty, Ph.; Thibault, J. P.

181

Engineering support for magnetohydrodynamic power plant analysis and design studies  

NASA Astrophysics Data System (ADS)

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.

1980-08-01

182

Computer controlled MHD power consolidation and pulse generation system  

NASA Astrophysics Data System (ADS)

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 2 prototype system. This report period work summarizes the accomplishments and covers the high points of the two year project.

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

183

Basic design of a prototype liquid metal magnetohydrodynamic power generator for solar and waste heat  

Microsoft Academic Search

Liquid metal magnetohydrodynamic power conversion (LMMHD PC) systems have been recently proposed for electrical power generation for various heat sources. These systems are based on extension of the Faraday law of induction to liquid metal. They contain high density liquid metal and a suitable thermodynamic fluid. A unique solar and waste heat coupled demonstration plant has been designed for generation

P. Satyamurthy; N. Venkatramani; A. M. Quraishi; A. Mushtaq

1999-01-01

184

Non-equilibrium MHD power generation using non-seeded argon plasma  

Microsoft Academic Search

Experiments with a shock tunnel non-equilibrium MHD power generator using non-seeded argon plasma are described. A linear generator of constant cross section and a diverging generator of diverging cross section were used. Effects of J x B force on the plasma flow when large powers are extracted from the generator were observed. MHD power generator performance is described by the

M. Miyata; Y. Kawamura

1976-01-01

185

Accretion disks: The magnetohydrodynamic powerhouse  

NASA Astrophysics Data System (ADS)

Accretion disks orbiting around compact objects such as white dwarfs, neutron stars and black holes are a central paradigm of high energy astrophysics. Accretion disks are believed to power systems such as x-ray binaries, active galactic nuclei, and quasars through the release of gravitational potential energy as gas spirals in. This infall requires the transfer of angular momentum outward from one fluid element to another. Thus the dynamics and evolution of accretion disks depend fundamentally upon this angular momentum transport process. Because accretion disks are composed of highly ionized conducting plasma with very high Reynolds number, the equations governing their evolution are those of (inviscid) magnetohydrodynamics (MHD). In disks the combination of a subthermal magnetic field and outwardly decreasing differential rotation leads to a powerful linear instability (the magnetorotational instability) which, in turn, generates MHD turbulence that produces a net Maxwell stress and the required angular momentum transport. The turbulence generates heat through dissipation at the viscous and resistive length-scales. Thus, accretion disks are systems where the power generation mechanism derives directly from a magnetohydrodynamic process. Fully global three-dimensional MHD simulations are now beginning to probe the properties of accretion disks from first principles.

Hawley, John F.

2003-05-01

186

Fluid dynamic aspects of liquid-metal gas two-phase magnetohydrodynamic power generators  

Microsoft Academic Search

An MHD system employing a liquid metal\\/gas two-phase MHD (LMMHD) generator is discussed as a promising alternative to conventional means of electrical power generation. The basic LMMHD thermodynamic cycle is described, along with the formulation of underlying principles and governing equations. The fundamental fluid dynamic problems related to two-phase velocity slip losses, ohmic losses, and friction and boundary layer shunt

G. Fabris; R. G. Hantman

1976-01-01

187

Fundamental analysis of space nuclear-MHD generator for gigawatt-level power  

NASA Astrophysics Data System (ADS)

SDI applications are likely to require SPRINT power sources with GWe-level potential at power densities of 1 kWe/kg. This goal for closed cycle systems can potentially be achieved with a combination of a nuclear gas core reactor and an MHD generator. The nuclear gas core reactor can deliver high volumetric density energy production and the MHD generator can provide high volumetric density energy conversion. A preliminary fundamental feasibility analysis of space nuclear MHD plants is presented.

Goodman, Julius; Maya, Isaac; Williams, J. Richard

188

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

189

Experimental studies on performance of a nonequilibrium disk MHD generator with radio-frequency preionization  

Microsoft Academic Search

The possibility of the improvement in performance of a nonequilibrium disk magnetohydrodynamics (MHD) generator by externally applying a radio frequency (RF) electromagnetic field (RF preionization) was examined experimentally. The MHD power generation experiments were carried out using a shock-tube driven disk MHD generator with the RF induction coils for the two inlet stagnation temperatures of 2275(±75) K and 2650(±50) K.

Takayasu Fujino; Tomoyuki Murakami; Yoshihiro Okuno; Hiroyuki Yamasaki

2003-01-01

190

MHD micropumping of power-law fluids: A numerical solution  

NASA Astrophysics Data System (ADS)

The performance of MHD micropumps is studied numerically assuming that the viscosity of the fluid is shear-dependent. Using power-law model to represent the fluid of interest, the effect of power-law exponent, N, is investigated on the volumetric flow rate in a rectangular channel. Assuming that the flow is laminar, incompressible, two-dimensional, but (approximately) unidirectional, finite difference method (FDM) is used to solve the governing equations. It is found that shear-thinning fluids provide a larger flow rate as compared to Newtonian fluids provided that the Hartmann number is above a critical value. There exists also an optimum Hartmann number (which is larger than the critical Hartmann number) at which the flow rate is maximum. The power-law exponent, N, strongly affects the optimum geometry depending on the Hartmann number being smaller or larger than the critical Hartmann number.

Moghaddam, Saied

2013-02-01

191

Specific Mass Estimates for A Vapor Core Reactor With MHD  

Microsoft Academic Search

This study investigated the development of a system concept for space power generation and nuclear electric propulsion based on a vapor core reactor (VCR) with magnetohydrodynamic (MHD) power conversion system, coupled to a magnetoplasma-dynamic (MPD) thruster. The VCR is a liquid-vapor core reactor concept operating with metallic uranium or uranium tetrafluoride (UFâ) vapor as the fissioning fuel and alkali metals

Travis Knight; Blair Smith; Samim Anghaie

2002-01-01

192

Wave turbulence in incompressible Hall magnetohydrodynamics  

Microsoft Academic Search

We investigate the steepening of the magnetic fluctuation power law spectra observed in the inner Solar wind for frequencies higher than 0.5 Hz. This high frequency part of the spectrum may be attributed to dispersive nonlinear processes. In that context, the long-time behavior of weakly interacting waves is examined in the framework of three-dimensional incompressible Hall magnetohydrodynamic (MHD) turbulence. The

Sébastien Galtier

2006-01-01

193

Conceptual Design of a Coal-Fired MHD (Magnetohydrodynamic) Retrofit Plant (Scholz Plant - Sneads, FL): Volume 1. Final Report.  

National Technical Information Service (NTIS)

Westinghouse Advanced Energy Systems (WAES), through Contract No. AC22-87PC79668, has completed a conceptual design study to evaluate a coal-fired MHD retrofit of a utility plant of sufficient size to demonstrate the technical and future economic viabilit...

1989-01-01

194

Analysis and design of an ultra-high-temperature, hydrogen-fueled MHD generator as an open cycle power supply  

SciTech Connect

The theoretical analysis of a partially-ionized hydrogen gas flow (gas temperatures of approximately 10,000 to 20,000 K) through a particular class of magnetohydrodynamic (MHD) generators and the preliminary design of these MHD generators as open cycle, electric power supplies are performed. Analysis of the gas flow through these ultra-high temperature MHD generators requires a coupled gas dynamics/radiative heat transfer solution. Gas dynamics are modeled by a set of quasi-one-dimensional, nonlinear differential equations which account for friction, convective and radiative heat transfer and the interaction between the ionized gas and applied magnetic field. Radiative heat transfer is modeled using non-gray, absorbing-emitting two- and three-dimensional P-1 approximations which permit an arbitrary variation of the spectral absorption coefficient with frequency. Gas dynamics and radiative heat transfer are coupled through the energy equation, and through the temperature-and density-dependent absorption coefficient. The resulting nonlinear, elliptic problem is solved by iterative methods in which relaxed values for radiative losses and temperature and density distributions are exchanged between computational models for the gas dynamics and radiative heat transfer. The design of efficient MHD generators is formulated as an optimization problem. The objective is to maximize the extraction ratio subject to several constraints, including limits on heat transfer to the generator walls, distorting of the applied magnetic field and maximum Hall parameters. A numerical optimization code is used to find local optima within the feasible design space, given some approximation of the actual radiative loss distribution within the generator. Actual coupled solutions for some of these designs are then generated.

Moder, J.P.

1990-01-01

195

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

196

Performance Calculations for 200-1000 Mwe Mhd/Steam Power Plants.  

National Technical Information Service (NTIS)

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 combusti...

P. J. Staiger

1981-01-01

197

Performance Calculations for 200-1000 MWe MHD/Steam Power Plants.  

National Technical Information Service (NTIS)

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 combusti...

P. J. Staiger

1981-01-01

198

MHD POWER GENERATION BY NON-THERMAL IONIZATION AND ITS APPLICATION TO NUCLEAR ENERGY CONVERSION  

Microsoft Academic Search

One of the most severe limitations of MHD power generation is the high ; temperatures required for thermal ionization. Two alternative, nonthermal ; ionization methods are considered: electron-bearn injection and fission-product ; radiation. Electron-beam injection appears to be the most promising method. The ; thermodynamic cycle of a power plant incorporating a MHD generator and a reactor ; is considered.

E. J. Sternglass; T. C. Tsu; G. L. Griffith; J. H. Wright

1963-01-01

199

Advanced LMMHD space power generation concept  

Microsoft Academic Search

Magnetohydrodynamic (MHD) power generation concept has been proposed and studied worldwide as one of the future power generation sources. An advanced one fluid two phase liquid metal (LM) MHD power generation concept was developed for space nuclear power generation design. The concept employs a nozzle to accelerate the liquid metal coolant to an acceptable velocity with Mach number greater than

Vincent Ho; Albert Wong; Kilyoo Kim; Vijay Dhir

1987-01-01

200

Magnetohydrodynamic projects at the CDIF. Quarterly technical progress report, January 1--March 31, 1992  

SciTech Connect

The Component Development and Integration Facility (CDIF) is a major U.S. Department of Energy magnetohydrodynamics (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 second quarter of FY92, a second external water leak on the iron-core magnet was repaired, and MHD testing was completed on February 11; this was the final testing of the workhorse hardware. Workhorse hardware was removed, and installation of the proof-of-concept (POC) combustor began.

Not Available

1992-08-01

201

Magnetohydrodynamic projects at the CDIF. Quarterly technical progress report, July 1--September 30, 1991  

SciTech Connect

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 fourth quarter of FY91, MHD testing was shut down. In addition to installing the new Data Acquisition System (DAS), activities such as rebuilding the channel, investigating and repairing the magnet leak, installing the slag removal system, and modifying existing systems were addressed.

Not Available

1991-12-31

202

Magnetohydrodynamic projects at the CDIF. Quarterly technical progress report, October 1, 1991--December 31, 1991  

SciTech Connect

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.

Not Available

1991-12-31

203

Plasma Relaxation in Hall Magnetohydrodynamics  

NASA Astrophysics Data System (ADS)

Parker's formulation of isotopological plasma relaxation process in magnetohydrodynamics (MHD) is extended to Hall MHD. The torsion coefficient ? 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 ? 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, Bhimsen K.

204

Electron magnetohydrodynamics  

NASA Astrophysics Data System (ADS)

Electron magnetohydrodynamics is a new branch of theoretical plasma physics with many applications to problems of pulsed plasmas and controlled magnetic fusion, astrophysics and physics of solids. EMH is the multicomponent MHD theory reduced, in the limit of short space and time scales and/or strong fields and high currents, to a form of electron hydrodynamics on a background of immovable ions. It is, in essence, hydrodynamic theory based on quasi-neutrality, the Hall effect and negligible ion motion. Many well-known MHD effects should be revised within the framework of EMH. Diamagnetic properties of quasi-steady plasma based on MHD theory are transformed into paramagnetism. In particular, instead of field diffusion, the result is magnetic field penetration into a conducting medium in the form of a shock wave. The ``classical'' skin problem with an oscillating field as a boundary condition has a nonclassical solution, demonstrating detection instead of the skin effect. Some new classes of instabilities have to be taken into account. These instabilities are faster than those resulting from MHD; hence, they are more effective in magnetic field reconnection and enhanced thermal conductivity. Nontrivial electron streams become possible in thin films, modifying their screen properties. In both Z-pinch and plasma diode, EMH dynamics result in some specific resistance of universal form. EMH effects are responsible for all aspects of plasma switching in the conductivity phase.

Gordeev, A. V.; Kingsep, A. S.; Rudakov, L. I.

1994-07-01

205

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

206

Electromagnetic Pulse and the Electric Power Network.  

National Technical Information Service (NTIS)

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) characteri...

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

1984-01-01

207

High-density magnetohydrodynamic energy conversion in a high-temperature inert gas  

SciTech Connect

We describe high-density magnetohydrodynamic (MHD) energy conversion in a high-temperature seed-free argon plasma, for which a compact disk-shaped Hall-type radial-flow MHD electrical power generator is used. The state of the MHD power-generating plasma changes with increasing total inflow temperature from 8200 to 9400 K; unstable behavior accompanied by the appearance of fine structures is transformed to a homogeneous and stable state. The attained enthalpy extraction efficiency is comparable to previous results using a conventional seeded gas. Furthermore, a high power output density is achieved even in relatively low-density magnetic flux.

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

2008-07-28

208

MHD power generation for the synthetic-fuels industry  

Microsoft Academic Search

The integration of open cycle MHD with various processes for the recovery of hydrocarbons for heavy oil deposits, oil sands, and oil shales are examined along with its use in producing medium Btu gas, synthetic natural gas and solvent refined coal. The major features of the MHD cycle which are of interest are: (a) the ability to produce hydrogen through

M. S. Jr

1982-01-01

209

Method and means of generating power from fossil fuels with a combined plasma and liquid-metal MHD cycle. [plasma MHD topping cycle and two-phase liquid metal MHD bottoming cycle  

Microsoft Academic Search

This patent relates to a method and means of generating power from fossil fuels with a combined plasma and liquid-metal MHD cycle. The heat required for operation of a two-phase liquid-metal MHD generator is obtained from the waste heat of a plasma MHD generator. The liquid metal is heated by passing it in heat exchange relationship to the combustion mixture

W. E. Amend

1975-01-01

210

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

211

Analysis of Thermal Economy of Combined Power Installations Employing Open-Cycle MHD Generators.  

National Technical Information Service (NTIS)

A mathematical model was used to analyze the thermodynamic efficiency of combined power plants incorporating MHD generators. The mathematical model devised by the authors consists of three parts. The first part is designed to describe processes determinin...

A. M. Roshchin L. S. Popyrin N. N. Pshenichnov

1972-01-01

212

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

213

Power take-off analysis for diagonally connected MHD channels  

SciTech Connect

The electrical loading of the power take-off region of diagonally connected MHD channels is investigated by a two-dimensional model. The study examines the loading schemes typical of those proposed for the U-25 and U-25 Bypass channels. The model is applicable for the following four cases: (1) connection with diodes only, (2) connection with diodes and equal resistors, (3) connection with diodes and variable resistances to obtain a given current distribution, and (4) connection with diodes and variable resistors under changing load. The analysis is applicable for the power take-off regions of single or multiple-output systems. The general behaviors of the current and the potential distributions in all four cases are discussed. The analytical results are in good agreement with the experimental data. It is found possible to design the electrical circuit of the channel in the take-off region so as to achieve a fairly even load current output under changing total load current.

Pan, Y.C.; Doss, E.D.

1980-01-01

214

Nonlinear Lagrangian MFE method for ideal MHD.  

National Technical Information Service (NTIS)

A nonlinear moving finite element method (MFE) for ideal magnetohydrodynamics (MHD) is developed and tested. The method is based on a variational principle in Lagrangian formulation of ideal MHD. A set of various FEM discretization based on this method is...

M. Benda A Bondeson L. O. Pekkari

1990-01-01

215

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

216

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

217

Magnetohydrodynamics of Plasma Relaxation  

Microsoft Academic Search

This monograph on magnetohydrodynamic (MHD) relaxation in plasmas by Ortolani and Schnack occupies a fascinating niche in the plasma physics literature. It is rare in the complex and often technically sophisticated subject of plasma physics to be able to isolate a topic and deal with it comprehensively in a mere 180 pages. Furthermore, it brings a refreshingly original and personal

J. W. Connor

1998-01-01

218

Numerical simulation of turbulent magnetohydrodynamic flows  

Microsoft Academic Search

The development of a computational tool for the solution of turbulent magnetohydrodynamic (MHD) flows is presented. For the MHD solver, option is given to solve the full MHD equations or consider the low magnetic Reynolds number formulation. For turbulence, the Reynolds Averaged approach is considered for its low requirement in terms of computational resources. Six turbulence models, ranging from simple

Jean-Francois Dietiker

2001-01-01

219

Energetic Particles and Magnetohydrodynamic Activity in SSX  

Microsoft Academic Search

Results from the Swarthmore Spheromak Experiment (SSX) indicate that formation and partial merging of two spheromak plasmas can be described well by a magnetohydrodynamic (MHD) picture in which there is substantial evolution towards force free states within each vessel, while reconnection activity, also described reasonably well by MHD, occurs in the region of interaction. MHD simulations (Lukin et al, Phys.

W. H. Matthaeus; G. Qin; V. S. Lukin; M. R. Brown

2001-01-01

220

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

221

Open-cycle magnetohydrodynamic electrical power generation: a review and future perspectives  

Microsoft Academic Search

R and D activities in the fields of gas-fired and coal-fired MHD power generation now discontinued are reviewed and major technological problems are summarized. Most of the problems originate from the low conductivity feature in the gas-fired case and in the low conductivity plus slagging environments in the coal-fired counterpart. It is emphasized that the high efficiency and CO2 recovery

Naoyuki Kayukawa

2004-01-01

222

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

223

Observation of voltage fluctuations in a Superconducting Magnet during MHD power generation  

Microsoft Academic Search

Fluctuating voltage signals on the potential taps of the ANL 5.0 T MHD Superconducting Dipole Magnet have been observed during MHD power generation at the U-25B Facility at the High Temperature Institute (IVTAN) Moscow, USSR. Various other thermodynamic and electrical parameters of the U-25B flow train have been recorded, and statistical analysis concerning correlations between the phenomena with a view

R. P. Smith; R. C. Niemann; M. R. Kraimer; T. E. Zinneman

1979-01-01

224

Pulsed self-excited MHD power generation at large energy densities  

Microsoft Academic Search

An experimental investigation of the physical, electromagnetic, and gas dynamic processes in the production of pulsed, self-excited MHD power is presented. The MHD channel is inserted into the electrically driven shock-tunnel section so that its front face provides a reflecting end wall for the shock; the plasma flows from the reflected region through a converging-diverging nozzle to achieve supersonic velocity

B. Zauderer; E. Tate

1980-01-01

225

Observation of voltage fluctuations in a superconducting magnet during MHD power generation  

Microsoft Academic Search

Fluctuating voltage signals on the potential taps of the ANL 5.0 T MHD Superconducting Dipole Magnet have been observed during MHD power generation at the U-25B Facility at the High Temperature Institute (IVTAN) Moscow, USSR. Various other thermodynamic and electrical parameters of the U-25B flow train have been recorded, and statistical analysis concerning correlations between the phenomena with a view

R. P. Smith; R. C. Niemann; M. R. Kraimer; T. E. Zinneman

1978-01-01

226

Observation of voltage fluctuations in a superconducting magnet during MHD power generation  

Microsoft Academic Search

Fluctuating voltage signals on the potential taps of the ANL 5.0 T MHD Superconducting Dipole Magnet have been observed during MHD power generation at the U-25B Facility at the High Temperature Institute (IVTAN) Moscow, USSR. Various other thermodynamic and electrical parameters of the U-25B flow train have been recorded, and statistical analysis concerning correlations between the phenomena with a view

R. P. Smith; R. C. Niemam; M. R. Kraimer; T. E. Zinneman

1979-01-01

227

Magnetohydrodynamic electrode  

DOEpatents

An electrode capable of withstanding high temperatures and suitable for use as a current collector in the channel of a magnetohydrodynamic (MHD) generator consists of a sintered powdered metal base portion, the upper surface of the base being coated with a first layer of nickel aluminide, an intermediate layer of a mixture of nickel aluminide - refractory ceramic on the first layer and a third or outer layer of a refractory ceramic material on the intermediate layer. The sintered powdered metal base resists spalling by the ceramic coatings and permits greater electrode compliance to thermal shock. The density of the powdered metal base can be varied to allow optimization of the thermal conductivity of the electrode and prevent excess heat loss from the channel.

Marchant, David D. (Richland, WA); Killpatrick, Don H. (Orland Park, IL)

1978-01-01

228

Potential role and technology status of closed-cycle MHD for light-weight nuclear space-power systems  

Microsoft Academic Search

If power is required in space for more than a large fraction of a day, steady state power sources (such as solar and nuclear) will have the lightest system weight. If megawatts of power are needed, closed cycle MHD systems (if successfully developed) have the potential of being very light and highly efficient. Such MHD generators are uniquely capable of

G. R. Seikel; B. Zauderer

1982-01-01

229

Diagnostic development and support of MHD test facilities. Technical progress report, April 1992June 1992  

Microsoft Academic Search

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

W. S. Shepard; R. L. Cook

1995-01-01

230

Diagnostic development and support of MHD test facilities. Final technical progress report, October 1992September 1993  

Microsoft Academic Search

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

W. S. Shepard; R. L. Cook

1995-01-01

231

Diagnostic development and support of MHD test facilities. Technical progress report, January 1992February 1992  

Microsoft Academic Search

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

W. S. Shepard; R. L. Cook

1995-01-01

232

Diagnostic development and support of MHD test facilities. Technical progress report, July 1992September 1992  

Microsoft Academic Search

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

W. S. Shepard; R. L. Cook

1995-01-01

233

Diagnostic development and support of MHD test facilities. Technical progress report, July 1991September 1991  

Microsoft Academic Search

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

W. S. Shepard; R. L. Cook

1995-01-01

234

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

Microsoft Academic Search

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

W. S. Shepard; R. L. Cook

1991-01-01

235

MHD-to-PIC transition for modeling of conduction and opening in a plasma opening switch  

Microsoft Academic Search

The plasma opening switch (POS) is a critical element of some inductive-energy-storage pulsed-power generators. Detailed understanding of plasma redistribution and thinning during the POS conduction phase can be gained through magnetohydrodynamic fluid (MHD) simulations. As space-charge separation and kinetic effects become important late in the conduction phase (beginning of the opening phase), MHD methods become invalid and particle-in-cell (PIC) methods

Joseph W. Schumer; Stephen B. Swanekamp; Paul F. Ottinger; Robert J. Commisso; Bruce V. Weber; David N. Smithe; Larry D. Ludeking

2001-01-01

236

Study of System Stabilization of Disk Type MHD Power Generation by Damping Resistor  

NASA Astrophysics Data System (ADS)

Effects of installed SDR (System Dumping Resistors) on the stability of open-cycle disk MHD generator and synchronous generator system connected in parallel to power transmission lines are numerically studied. Usually the SDR is used to absorb the output energy of synchronous generator and to get stability of the power transmission system when faults occur in the A.C. power transmission lines. In this paper, we propose to apply the SDR in the D.C. lines between the MHD generator and the primary side of connected line-commutated inverters. We show that the SDR is effective for the system stability by a time dependent numerical analysis.

Hayanose, Nobuhiko; Inui, Yoshitaka; Ishikawa, Motoo

237

Closed cycle MHD power generation system driven by nuclear reactor for space exploration  

Microsoft Academic Search

For deep space explorations, we have to develop high-efficiency, high-reliability and high-performance electric power generation system. In this paper, a closed cycle magnetohydrodynamic (CCMHD) power generation system directly driven by a nuclear fission reactor (NFR) was proposed and investigated. Output electric power level is multi-MWe. Particularly, influence of the number of compressor stages, the regenerator efficiency and the radiator temperature

N. Harada; C. Buttapeng

2004-01-01

238

An innovative demonstration of high power density in a compact MDH (magnetohydrodynamic) generator  

NASA Astrophysics Data System (ADS)

The present program was conducted by the University of Tennessee Space Institute (UTSI). It was by its nature a high risk experimental program to demonstrate the feasibility of high power density operation in a laboratory scale combustion driven MHD generator. Maximization of specific energy was not a consideration for the present program, but the results have implications in this regard by virtue of high energy fuel used. The power density is the ratio of the electrical energy output to the internal volume of the generator channel. The MHD process is a volumetric process and the power density is therefore a direct measure of the compactness of the system. Specific energy, is the ratio of the electrical energy output to consumable energy used for its production. The two parameters are conceptually interrelated. To achieve high power density and implied commensurate low system volume and weight, it was necessary to use an energetic fuel. The high energy fuel of choice was a mixture of powdered aluminum and carbon seeded with potassium carbonate and burned with gaseous oxygen. The solid fuel was burned in a hybrid combustion scheme wherein the fuel was cast within a cylindrical combustor in analogy with a solid propellant rocket motor. Experimental data is limited to gross channel output current and voltage, magnetic field strength, fuel and oxidizer flow rates, flow train external temperatures and combustor pressure. Similarly, while instantaneous oxidizer flow rates were measured, only average fuel consumption based on pre and post test component weights and dimensions was possible.

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

1990-06-01

239

Factors affecting MHD power generation using powdered aluminum fuels  

Microsoft Academic Search

A high-temperature fuel for compact MHD generators, consisting of carbon-aluminum powder mixtures, seeded with cesium, and liquid N2O4 oxidizer, was investigated using a modified NASA SP-273 chemical equilibrium computer program. It is shown that the observed high conductivity differences between the low-pressure conditions (at the generator entrance or downstream) and the high-pressure conditions of the combustion chamber were caused by

L. W. Crawford; J. T. Lineberry

1986-01-01

240

Uranium droplet nuclear reactor core with MHD generator  

Microsoft Academic Search

An innovative concept employing liquid uranium droplets as fuel in an ultrahigh-temperature vapor core reactor (UTVR) magnetohydrodynamic (MHD) generator power system for space power generation has been studied. Metallic vapor in superheated form acts as a working fluid for a closed-Rankine-type thermodynamic cycle. Usage of fuel and working fluid in this form assures certain advantages. The major technical issues emerging

Samim Anghaie; Ratan Kumar

1991-01-01

241

Strong magnetohydrodynamic turbulence with cross helicity  

NASA Astrophysics Data System (ADS)

Magnetohydrodynamics (MHD) is invoked to model different turbulent phenomena in magnetized plasmas. For instance, the energy spectrum of velocity and magnetic fluctuations in the solar wind obeys a power law spanning a broad range of scales, which has been associated to an inertial range of incompressible MHD turbulence. In addition to the total energy, ideal MHD equations conserve cross helicity which also undergoes a turbulent cascade to small scales. However, most of the current understanding of MHD turbulence is limited to the zero cross helicity case. Cross helicity quantifies the energy imbalance in Alfv'enic fluctuations oppositely moving along the background magnetic field. Although it is well established that turbulence in the solar wind is dominated by fluctuations moving away from the sun, only in recent years there have been an increased interest in addressing the role of cross helicity in MHD turbulence. Moreover, numerical simulations have also revealed the fundamental role that cross helicity plays in the turbulent cascade. In this talk, we present results from high resolution numerical simulations of steady-state incompressible MHD turbulence, with and without cross helicity. We show that in the zero cross helicity case the configuration space spontaneously develops regions of positive and negative cross-helicity. The obtained scaling of the energy spectrum (E^±) of fluctuations moving in opposite directions is consistent with simulations of incompressible MHD without cross-helicity by other groups. When cross helicity is injected, E^+ and E^- maintain the same inertial range scaling, but with differing amplitudes depending on the amount of injected cross-helicity. It is argued that in each of these correlated regions of imbalance, the scaling of E^+ and E^- is the same. When the total energy spectrum E^++E^- is averaged over those regions, the inertial range scaling is the same regardless of the amount of cross helicity in the system.

Perez, Jean C.

2009-11-01

242

Scale-locality of magnetohydrodynamic turbulence  

SciTech Connect

We investigate the scale-locality of cascades of conserved invariants at high kinetic and magnetic Reynolds 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 Elsaesser energies - are dominated by the contributions of local triads. Corresponding spectral transfers are also scale-local when defined using octave wavenumber bands. Flux and transfer of magnetic helicity may be dominated by nonlocal triads. The magnetic stretching term also may be dominated by non-local 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 non locally between disparate scales. We present supporting data from a 1024{sup 3} simulation of forced MHD turbulence.

Aluie, Hussein [Los Alamos National Laboratory; Eyink, Gregory L [JOHNS HOPKINS UNIV.

2009-01-01

243

A conceptual scheme for electrical power generation from nuclear waste heat using liquid metal magnetohydrodynamic energy converter  

Microsoft Academic Search

A novel conceptual scheme has been proposed for utilizing the nuclear waste for electrical power generation by using a Liquid Metal Magnetohydrodynamic Energy Converter (LMMHDEC). The heat released during interim storage of the vitrified nuclear waste is used for this purpose. Possible modifications in the canister design for obtaining a higher air outlet temperature have been suggested. The basic design

P. Satyamurthy; T. K. Thiyagarajan; N. Venkatramani

1995-01-01

244

Factors affecting MHD power generation using powdered aluminum fuels  

NASA Astrophysics Data System (ADS)

A high-temperature fuel for compact MHD generators, consisting of carbon-aluminum powder mixtures, seeded with cesium, and liquid N2O4 oxidizer, was investigated using a modified NASA SP-273 chemical equilibrium computer program. It is shown that the observed high conductivity differences between the low-pressure conditions (at the generator entrance or downstream) and the high-pressure conditions of the combustion chamber were caused by the pressure-dependent absorptions/dissociations of electrons by the AlO(-) ions.

Crawford, L. W.; Lineberry, J. T.

1986-05-01

245

Power and Transport Systems for Space Applications, Utilizing the MHD Method of Energy Conversion  

Microsoft Academic Search

The possibility of developing power and transport systems for space applications is examined. It is suggested to use an MHD generator utilizing inhomogeneous gas-plasma flows of inert gas as the source of electric energy in such systems. The plasma of the current layers may be in the state of “frozen ionization,” when the degree of ionization exceeds the equilibrium level

V. S. Slavin; V. V. Danilov; I. A. Kuzovatov; K. A. Finnikov; A. A. Gavrilov; K. Yu. Litvintsev; T. A. Milovidova

2002-01-01

246

THEORY OF THE APPLICATION OF ELECTRICAL IONIZATION TO THE MHD POWER GENERATOR  

Microsoft Academic Search

A method of increasing the ionization in MHD power generators by ; applying momentary electric fields to rare gases at 1000 to 2000 deg K seeded ; with low-ionization-potertial gases was investigated theoretically. It was found ; to be theoretically possible to design and construct such generators using the ; non-equilibrium ionization state that is created by the initial stage

S. Yano; T. Hiramoto

1962-01-01

247

Closed cycle MHD power generation system without alkali-metal seed  

Microsoft Academic Search

In this paper, the authors examine the possibility of a closed-cycle MHD power generation system without using alkali-metal seed. Based on the important role of seed, they propose the use of xenon as the seed material. Consideration by solving the Saha equation shows that helium must be used to obtain a notable enhancement of the electron number density from xenon

N. Harada

1996-01-01

248

Performance characteristics of a vortex-type MHD power generator - II  

Microsoft Academic Search

This paper deals with an analytical investigation of the performance characteristics of the same type of MHD power generator as treated in Part I of this paper, except in using a partially ionized gas as a working fluid, instead of an incompressible fluid. The compressibility, the variation of the properties of the working gas and the non-equilibrium ionization phenomenon are

I. Michiyoshi; M. Numano

1967-01-01

249

Optimization of the Oxidant Supply System for Combined Cycle Mhd Power Plants.  

National Technical Information Service (NTIS)

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...

A. J. Juhasz

1982-01-01

250

Production of MHD fluid  

DOEpatents

A hot gaseous fluid of low ash content, suitable for use in open-cycle MHD (magnetohydrodynamic) power generation, is produced by means of a three-stage process comprising (1) partial combustion of a fossil fuel to produce a hot gaseous product comprising CO.sub.2 CO, and H.sub.2 O, (2) reformation of the gaseous product from stage (1) by means of a fluidized char bed, whereby CO.sub.2 and H.sub.2 O are converted to CO and H.sub.2, and (3) combustion of CO and H.sub.2 from stage (2) to produce a low ash-content fluid (flue gas) comprising CO.sub.2 and H.sub.2 O and having a temperature of about 4000.degree. to 5000.degree.F.

Lacey, James J. (Library, PA); Kurtzrock, Roy C. (Bethel Park, PA); Bienstock, Daniel (Pittsburgh, PA)

1976-08-24

251

Double-duct liquid metal magnetohydrodynamic engine  

Microsoft Academic Search

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

Haaland; Carsten M

1997-01-01

252

Study of the processes resulting from the use of alkaline seed in natural gas-fired MHD facilities  

Microsoft Academic Search

Various ways of ionizing seed injection and recovery, applicable to open-cycle magnetohydrodynamic (MHD) power generation facilities, operating on sulfur-free gaseous fossil fuel, are discussed and experimentally verified. The physical and chemical changes of the seed and the heat and mass transfer processes resulting from seed application are investigated using the U-02 experimental MHD facility and laboratory test facilities. Engineering methods

M. A. Styrikovich; I. L. Mostinskii

1977-01-01

253

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

254

Decay of turbulent energy in a collisionless plasma: Hall MHD  

Microsoft Academic Search

Low frequency plasma turbulence such as that observed in the solar wind, is typically studied in a magnetohydrodynamic (MHD) limit. The usual expectation in MHD turbulence (as in hydrodynamic turbulence) is that the energetic large scale fluctuations, or \\

W. H. Matthaeus; P. Dmitruk; D. Smith; S. Ghosh; S. Oughton

2002-01-01

255

Effects of installed system dumping resistors on stability of open cycle disk type MHD generator connected to power transmission line  

Microsoft Academic Search

This study is performed as part of the wide research on large scale coal fired MHD generation systems. Faults in the power transmission line give remarkable fluctuations to the MHD generator and to the transmission network. Then, it is required to take countermeasures for stable operation of the generation system. The fluctuations do not converge to a stable state after

Nobuhuko Hayanose; Yoshitaka Inui; Motoo Ishikawa

2001-01-01

256

Accretion Disks---The MHD Powerhouse  

NASA Astrophysics Data System (ADS)

Accretion disks orbiting around compact objects such as white dwarfs, neutron stars and black holes are a central paradigm of high energy astrophysics. Accretion disks are believed to power such systems as X-ray binaries, active galactic nuclei and quasars through the release of gravitational potential energy as gas spirals in. This process requires the transfer of angular momentum outward from one fluid element to another. Thus the dynamics and evolution of accretion disks depend fundamentally upon this angular momentum transport process. Because accretion disks are composed of highly ionized conducting plasma with very high Reynolds number, the equations governing their evolution are those of (inviscid) ideal magnetohydrodynamics (MHD). In disks the combination of a subthermal magnetic field and outwardly decreasing differential rotation leads to a powerful linear instability (the magnetorotational instability) which, in turn, generates MHD turbulence that produces a net Maxwell stress and the required angular momentum transport. The turbulence, in turn, generates heat through dissipation at the viscous and resistive length-scales. Thus, accretion disks are systems where the power generation mechanism derives directly from a magnetohydrodynamic process. Fully global three dimensional MHD simulations are now beginning to probe the properties of accretion disks from first principles.

Hawley, John F.

2002-11-01

257

Gravitational Radiation from Primordial Helical Magnetohydrodynamic Turbulence  

Microsoft Academic Search

We consider gravitational waves (GWs) generated by primordial inverse-cascade helical magneto-hydrodynamical (MHD) turbulence produced by bubble collisions at the electroweak phase transitions (EWPT). Compared to the unmagnetized EWPT case, the spectrum of MHD-turbulence-generated GWs peaks at lower frequency with larger amplitude and can be detected by the proposed Laser Interferometer Space Antenna.

Tina Kahniashvili; Grigol Gogoberidze; Bharat Ratra

2008-01-01

258

Development program for MHD power generation: coal devolatilization. Final report, Volume VI, July 1, 1975September 30, 1976. [Exhaust gas from MHD generator used to pyrolyze coal for production of clean fuel gas of CO and H2  

Microsoft Academic Search

One of the many MHD power cycles which look attractive for producing electric power from coal is the Chemical Regeneration Cycle. In this cycle, pulverized coal is injected into and entrained in the hot exhaust of an MHD power genertor. A large percentage (approximately 70%) of the entrained coal devolatilizes under the rapid heating conditions, and the devolatilized fraction reacts

S. K. Ubhayakar; R. Gannon; D. Stickler

1977-01-01

259

Superconducting magnets for an MHD test facility and base load power plant  

Microsoft Academic Search

The development MHD power generation in the U.S. may involve the construction of an Engineering Test Facility (ETF) as a step toward a base-load or full-scale power plant. This paper describes the superconducting-magnet requirements for the ETF and base-load plants and gives the results to date in a program involving production of magnet reference designs for the two systems. Each

Z. J. J. Stekly; R. J. Thome; W. F. B. Punchard

1977-01-01

260

Hypersonic MHD Propulsion System Integration for the Mercury Lightcraft  

Microsoft Academic Search

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

L. N. Myrabo; R. J. Rosa

2004-01-01

261

Hypersonic MHD Propulsion System Integration for the Mercury Lightcraft  

Microsoft Academic Search

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

L. N. Myrabo; R. J. Rosa

2004-01-01

262

Computational fusion magnetohydrodynamics  

SciTech Connect

Simple magnetohydrodynamic models provide the framework for much of our understanding of the macroscopic behavior of magnetically confined laboratory plasmas. In even the simplest of models, however, the many different time and spatial scales, the multidimensionality, and the nonlinearity of the equations make finding solutions difficult. In realistic geometries obtaining quantitative results to aid our understanding, to interpret experiment, and to design new devices, involves the development of large scale numerical codes. During the past decade considerable effort has been extended in the fusion community to develop equilibrium, linear stability, and nonlinear time evolution codes in two and three dimensions, some of which have had a considerable impact on the fusion program. An overview of the various types of codes and numerical methods is given. Emphasis is on the spectrum of linear perturbations and ideal MHD stability, boundary layer methods and resistive MHD stability, and modeling of nonlinear, time evolution resistive MHD phenomena in tokamak configurations.

Grimm, R.C.

1984-01-01

263

Induction-drive magnetohydrodynamic propulsion  

SciTech Connect

The use of magnetohydrodynamic propulsion for marine applications is reviewed with emphasis on induction-drive systems such as the [open quotes]ripple[close quotes] motor. Comparisons are made with direct-drive MHD propulsion systems. Application to pumps for hazardous fluids and liquid-metal coolants is also discussed. 13 refs., 8 figs., 2 tabs.

Mitchell, D.L. (Mitchell Associates, Reston, VA (United States)); Gubser, D.U. (Naval Research Lab., Washington, DC (United States))

1993-08-01

264

Magnetohydrodynamic Propulsion for the Classroom  

Microsoft Academic Search

The cinema industry can sometimes prove to be an ally when searching for material with which to motivate students to learn physics. Consider, for example, the electromagnetic force on a current in the presence of a magnetic field. This phenomenon is at the heart of magnetohydrodynamic (MHD) propulsion systems. A submarine employing this type of propulsion was immortalized in the

Scott C. Dudley

2004-01-01

265

Gravitational radiation from primordial helical inverse cascade magnetohydrodynamic turbulence  

Microsoft Academic Search

We consider the generation of gravitational waves by primordial helical inverse-cascade magnetohydrodynamic (MHD) turbulence produced by bubble collisions at the electroweak phase transition. We extend the previous study 1 by considering both currently discussed models of MHD turbulence. For popular electroweak phase transition parameter values, the generated gravitational wave spectrum is only weakly dependent on the MHD turbulence model. Compared

Tina Kahniashvili; Leonardo Campanelli; Grigol Gogoberidze; Yurii Maravin; Bharat Ratra

2008-01-01

266

Gravitational radiation from primordial helical inverse cascade magnetohydrodynamic turbulence  

Microsoft Academic Search

We consider the generation of gravitational waves by primordial helical inverse-cascade magnetohydrodynamic (MHD) turbulence produced by bubble collisions at the electroweak phase transition. We extend the previous study by considering both currently discussed models of MHD turbulence. For popular electroweak phase transition parameter values, the generated gravitational wave spectrum is only weakly dependent on the MHD turbulence model. Compared with

Tina Kahniashvili; Leonardo Campanelli; Grigol Gogoberidze; Yurii Maravin; Bharat Ratra

2008-01-01

267

A numerical matching technique for linear resistive magnetohydrodynamics modes  

Microsoft Academic Search

A new numerical matching technique for linear stability analysis of resistive magnetohydrodynamics (MHD) modes is developed. The solution to the resistive reduced MHD equations in an inner layer with a finite width is matched onto the solution to the inertialess ideal MHD or the Newcomb equation by imposing smooth disappearance of parallel electric field in addition to the continuity of

M. Furukawa; S. Tokuda; L.-J. Zheng

2010-01-01

268

A pulse-amplitude-synthesis-and-control (PASC) consolidation\\/inversion system for Faraday connected MHD generators  

Microsoft Academic Search

The problem of consolidating and inverting a number of DC sources is common in interconnecting arrays of batteries, fuel cells, solar cells, multi-electrode pair magnetohydrodynamic (MHD) generators, etc. This paper describes a general technique for performing such power processing when applied to the specific example of consolidation followed by three phase inversion, of a number of DC sources produced by

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

1993-01-01

269

Superheater\\/intermediate temperature air heater tube corrosion tests in the MHD coal fired flow facility (Montana Rosebud POC tests)  

Microsoft Academic Search

Nineteen alloys have been exposed for approximately 1000 test hours as candidate superheater and intermediate temperature air heater tubes in a U.S. DOE facility dedicated to demonstrating Proof of Concept for the bottoming or heat and seed recovery portion of coal fired magnetohydrodynamic (MHD) electrical power generating plants. Corrosion data have been obtained from a test series utilizing a western

1996-01-01

270

Numerical Study on Feasibility of Pulsed-Heat-Source High-Temperature Inert Gas MHD Electrical Power Generation  

Microsoft Academic Search

The performance of a pulsed-heat-source, high-temperature inert gas MHD electrical power generator, which is a candidate space-based laser-to-electrical power converter, is examined by time-dependent, quasi-one dimensional, numerical simulation. In the present MHD generator, the inert gas is assumed to be ideally pulse heated to about 104 K within a short time (˜1 mus) in a stagnant energy input volume. The

Masaharu Matsumoto; Tomoyuki Murakami; Yoshihiro Okuno

2008-01-01

271

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.

272

Advanced LMMHD space power generation concept  

NASA Astrophysics Data System (ADS)

Magnetohydrodynamic (MHD) power generation concept has been proposed and studied worldwide as one of the future power generation sources. An advanced one fluid two phase liquid metal (LM) MHD power generation concept was developed for space nuclear power generation design. The concept employs a nozzle to accelerate the liquid metal coolant to an acceptable velocity with Mach number greater than unity. Such nozzle and the MHD power generator replace the turbogenerator of a high temperature Rankine turboelectric cycle concept. As a result, the power generation system contains no movable parts. This provides high reliability, which is a very important factor in space application.

Ho, Vincent; Wong, Albert; Kim, Kilyoo; Dhir, Vijay

273

Experimental studies on closed cycle MHD power generation with Fuji1 facility  

Microsoft Academic Search

Experimental studies on closed cycle MHD power generation with “Fuji-1” blow-down facility at the Tokyo Institute of Technology are presented. Recently, a new disk generator (Disk-F4) has been installed and a new seed injection system has been introduced from IVTAN (Institute of High Temperature in Russia). The design concept of the new generator channel is focused mainly on the reliability

Yoshihiro Okuno; Shigeharu Kabashima; Tetsuji Okamura; Kunio Yoshikawa; Kiyoshi Tsuji; Tetsuya Suekane; Susumu Shioda; Hiroyuki Yamasaki; Yasuo Hasegawa

1996-01-01

274

Advanced fusion MHD power conversion using the CFAR (compact fusion advanced Rankine) cycle concept  

Microsoft Academic Search

The CFAR (compact fusion advanced Rankine) cycle 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

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

1988-01-01

275

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

276

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

277

Parametric study of potential early commercial MHD power plants  

Microsoft Academic Search

Three different reference power plant configurations were considered with parametric variations of the various design parameters for each plant. Two of the reference plant designs were based on the use of high temperature regenerative air preheaters separately fired by a low Btu gas produced from a coal gasifier which was integrated with the power plant. The third reference plant design

F. A. Hals

1979-01-01

278

Two-dimensional radiation-magnetohydrodynamic simulations of SATURN imploding Z pinches  

Microsoft Academic Search

Z-pinch implosions driven by the SATURN device [D. D. Bloomquist etal., Proceedingsofthe 6thInstituteofElectricalandElectronicsEngineers (IEEE) PulsedPowerConference, Arlington, VA, edited by P. J. Turchi and B. H. Bernstein (IEEE, New York, 1987), p. 310] at Sandia National Laboratory are modeled with a two-dimensional radiation magnetohydrodynamic (MHD) code, showing strong growth of the magneto-Rayleigh–Taylor (MRT) instability. Modeling of the linear and nonlinear development

James H. Hammer; James L. Eddleman; Paul T. Springer; Max Tabak; Arthur Toor; Keith L. Wong; George B. Zimmerman; Chris Deeney; Russ Humphreys; Thomas J. Nash; Thomas W. L. Sanford; Rick B. Spielman; John S. de Groot

1996-01-01

279

MHD Flow Control and Power Generation in Low-Temperature Supersonic Flows  

NASA Astrophysics Data System (ADS)

The paper presents results of cold MHD flow deceleration and MHD power generation experiments using repetitively pulsed, short pulse duration, high voltage discharge to produce ionization in M=3 nitrogen and air flows. MHD effect on the flow is detected from the flow static pressure measurements. Retarding Lorentz force applied to the flow produces a static pressure increase of up to 17-20%, while accelerating force of the same magnitude results in static pressure increase of up to 5-7%. No discharge polarity effect on the static pressure was detected in the absence of the magnetic field. The fraction of the discharge input power going into Joule heat in nitrogen and dry air, inferred from the present experiments, is low, ?=0.1, primarily because energy remains frozen in the vibrational energy mode of nitrogen. Comparison of the experimental results with the modeling calculations shows that the retarding Lorentz force increases the static pressure rise produced by Joule heating of the flow, while the accelerating Lorentz force reduces the pressure rise. This result provides first direct evidence of cold supersonic flow deceleration by Lorentz force.

Adamovich, Igor; Nishihara, Munetake

2006-10-01

280

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

NASA Astrophysics Data System (ADS)

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

281

Compendium of MHD-related terminology.  

National Technical Information Service (NTIS)

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...

A. T. Hart D. A. Lofftus D. A. Rudberg R. A. Green

1990-01-01

282

Eighth International Conference on MHD Electrical Power Generation. Volume 2.  

National Technical Information Service (NTIS)

The proceedings contain the results of most recent R and D work aimed at practical realization of this advanced method of electrical power generation. The papers presented to the Conference deal with heat-generating schemes and cycles, conceptual and deta...

1983-01-01

283

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

284

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

285

Overview of DOE's advanced/MHD coal combustor development programs  

SciTech Connect

An overview of DOE research on combustion devices covers work under the Coal-Fired Magnetohydrodynamic (MHD) Power Systems Program and Advanced Combustion Systems Program. The work covers a broad range of technology at various stages of development. The MHD combustor effort will develop a durable, low heat-loss device capable of operating at pressure of up to eight atmospheres, producing combustion gases at temperatures approaching 5000 deg. F, and rejecting, as slag, at least 70% of the mineral matter contained in the coal. The scope of the Advanced Coal Combustion Systems Program is to develop and evaluate low-cost, environmentally acceptable technologies for a broad range of users. The program includes industrial participation and cost sharing. Among the efforts in progress, the TRW 50 MWt MHD combustor and its related 50 MMBtu/hr commercial/industrial variant appear to be the most highly developed at this time. 6 references, 5 figures, 1 table.

Carabetta, R.A.; McCann, C.R.; Kurtzrock, R.C.

1985-08-01

286

Plasma relaxation and topological aspects in Hall magnetohydrodynamics  

NASA Astrophysics Data System (ADS)

Parker's formulation of isotopological plasma relaxation process in magnetohydrodynamics (MHD) is extended to Hall MHD. The torsion coefficient ? 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 ? 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.

2012-07-01

287

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

288

Energy Cascades in MHD  

NASA Astrophysics Data System (ADS)

Most astrophysical and planetary systems e.g., solar convection and stellar winds, are in a turbulent state and coupled to magnetic fields. Understanding and quantifying the statistical properties of magneto-hydro-dynamic (MHD) turbulence is crucial to explain the involved physical processes. Although the phenomenological theory of hydro-dynamic (HD) turbulence has been verified up to small corrections, a similar statement cannot be made for MHD turbulence. Since the phenomenological description of Hydrodynamic turbulence by Kolmogorov in 1941 there have been many attempts to derive a similar description for turbulence in conducting fluids (i.e Magneto-Hydrodynamic turbulence). However such a description is going to be based inevitably on strong assumptions (typically borrowed from hydrodynamics) that do not however necessarily apply to the MHD case. In this talk I will discuss some of the properties and differences of the energy and helicity cascades in turbulent MHD and HD flows. The investigation is going to be based on the analysis of direct numerical simulations. The cascades in MHD turbulence appear to be a more non-local process (in scale space) than in Hydrodynamics. Some implications of these results to turbulent modeling will be discussed

Alexakis, A.

2009-04-01

289

Experimental Performance of Two Segmented Wall Magnetohydrodynamic Electric Power Generators Using Solid-Fueled Combustors.  

National Technical Information Service (NTIS)

A test program was conducted on a vertically segmented wall (Hall) and a diagonally segmented wall (45-deg-slant) magnetohydrodynamic generator. The internal width of the 48-in.-long generator channel was 2 in.; the height diverged from 4 in. at the inlet...

M. A. Nelius R. J. LeBoeuf J. D. McNeese

1968-01-01

290

Experimental Performance of a 60-Deg-Slant, Segmented Wall, Magnetohydrodynamic Electric Power Generator.  

National Technical Information Service (NTIS)

A test program was conducted on a 60-deg-slant, segmented wall, magnetohydrodynamic generator. The generator channel was 48-in. in length with an inside width of 2-in., and diverged from 4-in. in height at the channel inlet to 6-in. in height at the chann...

R. J. LeBoeuf J. D. McNeese

1967-01-01

291

Solar flares and focused energy transport by MHD waves  

NASA Astrophysics Data System (ADS)

Context. Transport of flare energy from the corona to the chromosphere has traditionally been assigned to electron beams; however, interest has recently been renewed in magnetohydrodynamic (MHD) waves as a complementary or alternative mechanism. Aims: We determine whether, and under what conditions, MHD waves deliver spatially localised energy to the chromosphere, as required if MHD waves are to contribute to emission from flare ribbons and kernels. This paper also highlights several properties of MHD waves that are relevant to solar flares and demonstrates their application to the flare problem. Methods: Transport is investigated using a magnetic arcade model and 2.5D MHD simulations. Different wave polarisations are considered and the effect of fine structuring transverse to the magnetic field is also examined. Ray tracing provides additional insight into the evolution of waveguided fast waves. Results: Alfvén waves are very effective at delivering energy fluxes to small areas of chromosphere, localisation being enhanced by magnetic field convergence and phase mixing. Fast waves, in the absence of fine coronal structure, are more suited to powering emission from diffuse rather than compact sources; however, fast waves can be strongly localised by coronal waveguides, in which case focused energy is best transported to the chromosphere when waveguides are directly excited by the energy release. Conclusions: MHD waves pass an important test for inclusion in future flare models.

Russell, A. J. B.; Stackhouse, D. J.

2013-10-01

292

MHD-EMP protection guidelines  

Microsoft Academic Search

A nuclear detonation at altitudes several hundred kilometers above the earth will severely distort the earth's magnetic field and result in a strong magnetohydrodynamic electromagnetic pulse (MHD-EMP). The geomagnetic disturbance interacts with the soil to induce current and horizontal electric gradients. MHD-EMP, also called E3 since it is the third component of the high-altitude EMP (HEMP), lasts over 100 s

P. R. Barnes; E. F. Vance

1992-01-01

293

An AC magnetohydrodynamic micropump: towards a true integrated microfluidic system  

SciTech Connect

An AC Magnetohydrodynamic (MHD) micropump has been demonstrated in which the Lorentz force is used to propel an electrolytic solution along a microchannel etched in silicon. This micropump has no moving parts, produces a continuous (not pulsatile) flow, and is compatible with solutions containing biological specimens. micropump, using the Lorentz force as the pumping mechanism for biological analysis. The AC Magnetohydrodynamic (MHD) micropump investigated produces a continuous flow and allows for complex microchannel design.

Lee, A P; Lemoff, A V; McConaghy, C F; Miles, R R

1999-03-01

294

MHD-EMP Analysis and Protection.  

National Technical Information Service (NTIS)

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 glob...

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

1993-01-01

295

Magnetogasdynamic phenomena in pulsed MHD flows  

Microsoft Academic Search

This report examines some of the detailed structure of magnetogasdynamic flows encountered in pulsed magnetohydrodynamic (MHD) generators. Two illustrations of magnetogasdynamic nonuniformities are considered. The first is for conventional explosive-driven MHD generators. Here we reveal the detailed structure of the deceleration of the conducting slug formed by the compression of plasma between the explosive-driven shock wave and its following contact

S. T. Demetriades; D. M. Markham; C. D. Maxwell; D. A. Oliver; T. F. Swean

1978-01-01

296

Energy Decay Laws in Strongly Anisotropic Magnetohydrodynamic Turbulence  

SciTech Connect

We investigate the influence of a uniform magnetic field B{sub 0}=B{sub 0}e{sub parallel} on energy decay laws in incompressible magnetohydrodynamic (MHD) turbulence. The nonlinear transfer reduction along B{sub 0} is included in a model that distinguishes parallel and perpendicular directions, following a phenomenology of Kraichnan. We predict a slowing down of the energy decay due to anisotropy in the limit of strong B{sub 0}, with distinct power laws for energy decay of shear- and pseudo-Alfven waves. Numerical results from the kinetic equations of Alfven wave turbulence recover these predictions, and MHD numerical results clearly tend to follow them in the lowest perpendicular planes.

Bigot, Barbara [Institut d'Astrophysique Spatiale (IAS), Batiment 121, F-91405 Orsay (France); Universite Paris-Sud XI and CNRS (UMR 8617) (France); Laboratoire Cassiopee, UMR 6202, OCA, BP 42229, 06304 Nice Cedex 4 (France); Galtier, Sebastien [Institut d'Astrophysique Spatiale (IAS), Batiment 121, F-91405 Orsay (France); Universite Paris-Sud XI and CNRS (UMR 8617) (France); Politano, Helene [Laboratoire Cassiopee, UMR 6202, OCA, BP 42229, 06304 Nice Cedex 4 (France)

2008-02-22

297

Hall Magnetohydrodynamics and Its Applications to Laboratory and Cosmic Plasma  

Microsoft Academic Search

With early critical views by Lighthill [1] as the starting point, a revision is performed of the classical magnetohydrodynamic (MHD) theory for the magnetized plasma properties. The importance of retaining the Hall term and using a two-fluid plasma description is stressed. The plasma Hall Magnetohydrodynamics (HMHD) description is derived by accounting for the noncentral character of the internal particle-particle forces

E. A. Witalis

1986-01-01

298

Nuclear Magnetohydrodynamic EMP, Solar Storms, and Substorms  

Microsoft Academic Search

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≲10-1 V\\/m and lasts ≲102 sec, whereas for solar storms E≳10-2 V\\/m and lasts ≳103 sec. Although the solar storm electric field

Mario Rabinowitz; A. P. Sakis Meliopoulos; Elias N. Glytsis; George J. Cokkinides

1992-01-01

299

Nuclear magnetohydrodynamic EMP, solar storms, and substorms  

Microsoft Academic Search

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

Mario Rabinowitz; A. P. Sakis Meliopoulos; Elias N. Glytsis; George J. Cokkinides

1992-01-01

300

Wave turbulence in incompressible Hall magnetohydrodynamics  

NASA Astrophysics Data System (ADS)

We investigate the steepening of the magnetic fluctuation power law spectra observed in the inner Solar wind for frequencies higher than 0.5 Hz. This high frequency part of the spectrum may be attributed to dispersive nonlinear processes. In that context, the long-time behavior of weakly interacting waves is examined in the framework of three-dimensional incompressible Hall magnetohydrodynamic (MHD) turbulence. The Hall term added to the standard MHD equations makes the Alfvén waves dispersive and circularly polarized. We introduce the generalized Elsässer variables and, using a complex helicity decomposition, we derive for three-wave interaction processes the general wave kinetic equations; they describe the nonlinear dynamics of Alfvén, whistler and ion cyclotron wave turbulence in the presence of a strong uniform magnetic field B_0 \\(e}_{Vert) . Hall MHD turbulence is characterized by anisotropies of different strength: (i) for wavenumbers textit{kd}_i {?} 1 (d_i is the ion inertial length) nonlinear transfers are essentially in the direction perpendicular (?) to B_0; (ii) for textit{kd}_i {?} 1 nonlinear transfers are exclusively in the perpendicular direction; (iii) for textit{kd}_i ˜ 1, a moderate anisotropy is predicted. We show that electron and standard MHD turbulence can be seen as two frequency limits of the present theory but the standard MHD limit is singular; additionally, we analyze in detail the ion MHD turbulence limit. Exact power law solutions of the master wave kinetic equations are given in the small- and large-scale limits for which we have, respectively, the total energy spectra E(k_{?},k_{Vert}) ˜ k_{?}(-5/2) |k_{Vert}|(-1/2) and E(k_{?},k_{Vert}) ˜ k_{?}(-2) . An anisotropic phenomenology is developed to describe continuously the different scaling laws of the energy spectrum; one predicts E(k_{?},k_{Vert}) ˜ k_{?}(-2) |k_{Vert}|(-1/2) (1+k_{?}(2d_) i(2)(-1/4)) . Non-local interactions between Alfvén, whistler and ion cyclotron waves are investigated; a non-trivial dynamics exists only when a discrepancy from the equipartition between the large-scale kinetic and magnetic energies happens.

Galtier, Sébastien

301

Magnetohydrodynamic generators in power generation. Citations from the NTIS data base  

NASA Astrophysics Data System (ADS)

The citations include research on performance, costs, efficiency, and design of MHD generators and their use in fusion and fission reactors, and fossil fueled plants. This updated bibliography contains 272 abstracts, 40 of which are new entries to the previous edition.

Reed, W. E.

1980-06-01

302

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

303

Uranium droplet nuclear reactor core with MHD generator  

NASA Astrophysics Data System (ADS)

An innovative concept employing liquid uranium droplets as fuel in an ultrahigh-temperature vapor core reactor (UTVR) magnetohydrodynamic (MHD) generator power system for space power generation has been studied. Metallic vapor in superheated form acts as a working fluid for a closed-Rankine-type thermodynamic cycle. Usage of fuel and working fluid in this form assures certain advantages. The major technical issues emerging as a result involve a method for droplet generation, droplet transport in the reactor core, heat generation in the fuel and transport to the metallic vapor, and materials compatibility. A qualitative and quantitative attempt to resolve these issues has indicated the promise and tentative feasibility of the system.

Anghaie, Samim; Kumar, Ratan

304

MHD System of Liquid Metals . Sistemi MHD a Metallo Liquido.  

National Technical Information Service (NTIS)

Maximum analysis of the liquid metal magnetohydrodynamics of various systems was made with emphasis on the thermody-namic cycles. Several schemes for the LM-MHD are developed based on two phase flow: a liquid metal, as the working fluid, and a vapor as th...

R. Chiavaccini

1972-01-01

305

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

306

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); Deeds, W. Edward (Knoxville, TN)

1999-01-01

307

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

308

Magnetohydrodynamic cosmologies.  

National Technical Information Service (NTIS)

We analyse a class of cosmological models in magnetohydrodynamic regime extending and completing the results of a previous paper. The material content of the models is a perfect fluid plus electromagnetic fields. The fluid is neutral in average but admits...

R. Portugal I. D. Soares

1991-01-01

309

Energetic particles and magnetohydrodynamic activity in the Swarthmore Spheromak Experiment  

Microsoft Academic Search

Results from the Swarthmore Spheromak Experiment (SSX) [M. R. Brown, Phys. Plasmas 6, 1717 (1999)] indicate that formation and partial merging of two spheromak plasmas can be described well by a magnetohydrodynamic (MHD) picture in which there is substantial evolution towards force free states within each vessel, while reconnection activity, also described reasonably well by MHD, occurs in the region

G. Qin; V. S. Lukin; C. D. Cothran; M. R. Brown; W. H. Matthaeus

2001-01-01

310

Magnetohydrodynamic turbulence and angular momentum transport in accretion disks  

Microsoft Academic Search

It is currently believed that angular momentum transport in accretion disks is mediated by magnetohydrodynamic (MHD) turbulence driven by the magnetorotational instability (MRI). More than 15 years after its discovery, an accretion disk model that incorporates the MRI as the mechanism driving the MHD turbulence is still lacking. This dissertation constitutes the first in a series of steps towards establishing

Martin Elias Pessah

2007-01-01

311

Analytical and sampling methodology used for determining the impact of a MHD test facility. [Al, As, Ca, Cd, Fe, K, Mn, Pb, Zn, B, Be, Bi, Co, Cr, Hg, Mg, Mo, Ni, Sb, Se, Sn, V  

Microsoft Academic Search

The suitability of various analytical and sampling methodologies for the determination of the environmental impact of a test scale MHD (magnetohydrodynamic) power generation facility is evaluated. Media which were sampled included airbourne particulates, soils, vegetation and natural waters. Analytical techniques examined include plasma emission and atomic absorption spectrometry and ion chromatography. Except in the case of the sampling of particulates

Jenke

1984-01-01

312

Magnetohydrodynamics in the extreme relativistic limit  

NASA Astrophysics Data System (ADS)

We present two new formulations of magnetohydrodynamics (MHD), in the limit where the inertia of the charge carriers can be neglected. The first employs Lagrangian coordinates and generalizes Newcomb's formalism to allow for a variable time slicing. It contains an extremely simple prescription for generalizing the action of a relativistic Nambu-Goto string to four dimensions. It is also related by a duality transformation to the action presented by Achterberg. This transformation causes the perturbed and unperturbed Lagrangian coordinates to exchange roles as dynamical fields and background spacetime. Our second formulation introduces massless electrically charged fermions as the current carrying modes, and considers long wavelength perturbations with ?2,k2?<MHD condition. The fundamental modes of the magnetofluid in this limit comprise two oppositely directed Alfvén modes and the fast mode, all of which propagate at the speed of light. We calculate the nonlinear interaction between two Alfvén modes, and show that in both formulations it satisfies the same simple expression. This provides the first exact treatment of the effects of compressibility on nonlinear interactions between MHD waves. We then summarize the interactions between Alfvén modes, between Alfvén modes and fast modes, and between fast modes in terms of a simplified Lagrangian. The three-mode interaction between fast modes is a magnetohydrodynamic analogue of the QED process of photon splitting, but occurs in background magnetic fields of arbitrary strength. The scaling behavior of an Alfvén wave cascade in a box is derived, paying close attention to boundary conditions. This result also applies to nonrelativistic MHD media and differs from those obtained by previous authors in the nonrelativistic regime. Finally, we briefly outline the physical processes which determine the inner scale of such a cascade in neutron star magnetospheres, black hole accretion disks, and ?-ray burst sources. At low charge density, the waves at the inner scale may become charge starved; whereas Compton drag is the dominant dissipative mechanism at large optical depth to electron scattering. A turbulent cascade leads to effective dissipation even in optically thick media, and in particular can significantly raise the entropy-baryon ratio in the relativistic outflows that power cosmological ?-ray bursts.

Thompson, Christopher; Blaes, Omer

1998-03-01

313

Experimental MHD Generator of the Academy of Sciences and Ministry of Power Engineering of the Ukrainian SSR.  

National Technical Information Service (NTIS)

Scientifical and engineering background is given of the experimental MHD generator, built on the basis of an operating power station. The generator is run on the combustion products of natural gas with consumption of 3-10 kg/sec; it includes a rearend ste...

A. N. Milyakh E. P. Strashinin G. A. Klimenko I. T. Shvets N. I. Mazur

1972-01-01

314

High power MHD system - facility status and magnet test results. Final report 1 Jul 77-30 Sep 80  

Microsoft Academic Search

AEDC has been requested by the Aero Propulsion Laboratory to design, fabricate, and install facility hardware necessary to conduct tests to demonstrate the performance of high power MHD generator systems developed by AFWAL contractors. This report summarizes the AEDC effort since program inception, describes the facility under development, gives the status of each major facility component, and summarizes the results

1982-01-01

315

Studies on two-phase flow mixing pertaining to liquid-metal magnetohydrodynamic power generation  

Microsoft Academic Search

The experimental work described was conducted to evaluate the fluid mechanical performance of various two-phase liquid-metal MHD mixer designs. The results indicate that two-phase flow turbulence is not helpful in generating a homogeneous two-phase flow at high void fractions, even in strongly surface-active systems. This is somewhat contrary to the behavior at low void fractions, where turbulence breaks up large

G. Fabris; P. F. Dunn; J. C. F. Chow; R. Kolp

1979-01-01

316

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

317

Impulse formulations of Hall magnetohydrodynamic equations  

NASA Astrophysics Data System (ADS)

Impulse formulations of Hall magnetohydrodynamic (MHD) equations are developed. The Lagrange invariance of a generalized ion magnetic helicity is established for Hall MHD. The physical implications of this Lagrange invariant are discussed. The discussion is then extended to compressible Hall MHD and a generalized ion magnetic potential helicity Lagrange invariant is established. The physical implications of the generalized ion magnetic potential helicity Lagrange invariant are shown to be the same, as to be expected, as those of the generalized ion magnetic helicity Lagrange invariant.

Shivamoggi, Bhimsen K.

2009-02-01

318

Heating Diagnostics with MHD Waves  

NASA Astrophysics Data System (ADS)

The heating of the solar atmosphere is a fundamental problem of modern solar and astrophysics. A review of the seismological aspects of magnetohydrodynamic (MHD) waves with an emphasis on standing longitudinal waves in the context of coronal heating is presented. Efforts made recently may be split into two categories: forward modelling and data inversion. Forward modelling can be applied to predict the observational footprints of various heating scenarios. A new diagnostic method based on the analysis of Doppler shift time series is outlined with specific application to solar coronal conditions. The power of the method is demonstrated and tested using synthetic data and comparing them with actual high-resolution (e.g. SoHO/SUMER) observations. Further, related recent examples of standing longitudinal oscillations in coronal loop structures observed with the new Hinode/EIS instrument are also presented. These latter observations provide an advanced ground for MHD seismology as a tool for plasma heating diagnostics in the atmosphere of the Sun.

Taroyan, Y.; Erdélyi, R.

2009-12-01

319

Divergence-Free Adaptive Mesh Refinement for Magnetohydrodynamics  

Microsoft Academic Search

Several physical systems, such as nonrelativistic and relativistic magnetohydrodynamics (MHD), radiation MHD, electromagnetics, and incompressible hydrodynamics, satisfy Stoke's law type equations for the divergence-free evolution of vector fields. In this paper we present a full-fledged scheme for the second-order accurate, divergence-free evolution of vector fields on an adaptive mesh refinement (AMR) hierarchy. We focus here on adaptive mesh MHD. However,

Dinshaw S. Balsara

2001-01-01

320

Magnetohydrodynamic Augmentation of Pulse Detonation Engines  

Microsoft Academic Search

Pulse detonation engines (PDEs) are the focus of increasing attention due to their potentially superior performance over constant pressure engines. Yet due to its unsteady chamber pressure, the PDE system will either be over- or under-expanded for the majority of the cycle, with energy being used without maximum gain. Magnetohydrodynamic (MHD) augmentation offers the opportunity to extract energy and apply

Christopher Zeineh; Lord Cole; Ann Karagozian

2010-01-01

321

Advances in Solar System Magnetohydrodynamics, 1991  

Microsoft Academic Search

Most of the solar system exists in the plasma state (the fourth state of matter). Its subtle nonlinear interaction with the magnetic field can be described by the equations of magnetohydrodynamics (MHD). Over the past few years this important and complex field of research has been actively pursued and increasingly diversely applied to the fields of geophysics, space physics, and

Eric R. Priest; Alan W. Hood

1991-01-01

322

Magnetohydrodynamics in the extreme relativistic limit  

Microsoft Academic Search

We present two new formulations of magnetohydrodynamics (MHD), in the limit where the inertia of the charge carriers can be neglected. The first employs Lagrangian coordinates and generalizes Newcomb's formalism to allow for a variable time slicing. It contains an extremely simple prescription for generalizing the action of a relativistic Nambu-Goto string to four dimensions. It is also related by

Christopher Thompson; Omer Blaes

1998-01-01

323

BOOK REVIEW: Magnetohydrodynamics of Plasma Relaxation  

Microsoft Academic Search

This monograph on magnetohydrodynamic (MHD) relaxation in plasmas by Ortolani and Schnack occupies a fascinating niche in the plasma physics literature. It is rare in the complex and often technically sophisticated subject of plasma physics to be able to isolate a topic and deal with it comprehensively in a mere 180 pages. Furthermore, it brings a refreshingly original and personal

S. Ortolani; D. Schnack

1998-01-01

324

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

NASA Astrophysics Data System (ADS)

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 Rw and on-axis safety factor q0. 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 q0 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 q0 sufficiently large (q0 > 2.8 for the power plant and q0 > 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.

2010-12-01

325

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

326

Flow Analysis of Non-Newtonian Blood in a Magnetohydrodynamic Pump  

Microsoft Academic Search

The magnetohydrodynamic (MHD) pump has attracted a lot of attention in today's technology especially for biotechnology and drug delivery applications. In a MHD pump, the magnetic field creates a dynamic electromotive force that moves the fluid forward. The knowledge of the details of the flow field is needed for design of a MHD pump. The purpose of this study is

A. Shahidian; M. Ghassemi; S. Khorasanizade; M. Abdollahzade; G. Ahmadi

2009-01-01

327

Aerodynamic and Thermal Operating Characteristics of a 45-Deg-Slant, Segmented Wall, Magnetohydrodynamic Generator Channel under No-Power Conditions.  

National Technical Information Service (NTIS)

A test program was conducted to determine the aerodynamic and thermal operating characteristics of a 45-deg-slant, segmented wall, magnetohydrodynamic generator channel under no-power conditions. The generator channel was 30.3 in. long with an inside diam...

M. A. Nelius R. J. LeBoeuf J. D. McNeese

1968-01-01

328

Fundamentals of numerical magnetohydrodynamics  

SciTech Connect

Magnetohydrodynamics is a fluid model for the motion of an ionized gas in a magnetic field. In its ideal, non-dissipative form, the Lundquist equations, it has the same mathematical character as the model for gas dynamics. It gives, in the same way, a self-consistent description of the fluid dynamics, including the exchange of momentum and energy between the field and the fluid. However, because of the greater complexity of the physics which they describe, some aspects of the solutions are quite different. The magnetic field introduces a strong anisotropic character to the medium which causes wave propagation to depend on the direction of propagation with respect of the magnetic field. In addition, there are several distinct speeds so that, in general, the responses to disturbances are quite complex. To capture the principal features of the solutions in numerical calculations, several problems must be addressed. Some of these problems are unique to MHD: for example, preserving the solenoidality of the magnetic field. Others are similar to ordinary gas dynamics, such as energy conservation, numerical stability, and computational diffusion, but are more complex or have different consequences for MHD than for ordinary fluid flow. These fundamental problems in the numerical solution of the MHD equations are discussed as four topics: the dispersion of the Lundquist equations and the dispersion and stability of finite difference approximations; the conservation laws of MHD and the achievement of conservation in the numerical solutions; a discussion of convective transport and its role in computational diffusion; and finally, a method for preserving the solenoidality of the magnetic field.

Brackbill, J.U.

1987-01-01

329

Symmetry transforms for ideal magnetohydrodynamics equilibria.  

PubMed

A method for constructing ideal magnetohydrodynamics (MHD) equilibria is introduced. The method consists of the application of symmetry transforms to any known MHD equilibrium [ O. I. Bogoyavlenskij, Phys. Rev. E. 62, 8616, (2000)]. The transforms break the geometrical symmetries of the field-aligned solutions and produce continuous families of the nonsymmetric MHD equilibria. The method of symmetry transforms also allows to obtain MHD equilibria with current sheets and exact solutions with noncollinear vector fields B and V. A model of the nonsymmetric astrophysical jets outside of their accretion disks is developed. The total magnetic and kinetic energy of the jet is finite in any layer c(1)MHD equilibria that model ball lightning with dynamics of plasma inside the fireball. PMID:12513610

Bogoyavlenskij, Oleg I

2002-11-22

330

Aharonov–Bohm effects in magnetohydrodynamics  

NASA Astrophysics Data System (ADS)

It is shown that an Aharonov–Bohm (AB) effect exists in magnetohydrodynamics (MHD). This effect is best described in terms of the MHD variational variables (Kats, 2004; Yahalom and Lynden-Bell, 2008; Yahalom, 2010) [1,10,12]. If a MHD flow has a non-trivial topology some of the functions appearing in the MHD Lagrangian are non-single-valued. These functions have properties similar to the phases in the AB celebrated effect (Aharonov and Bohm, 1959; van Oudenaarden et al., 1998) [2,3]. While the manifestation of the quantum AB effect is in interference fringe patterns (Tonomura et al., 1982) [4], the manifestation of the MHD Aharonov–Bohm effects are through new dynamical conservation laws.

Yahalom, Asher

2013-10-01

331

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

332

[Nonlinear magnetohydrodynamics  

SciTech Connect

Theoretical predictions were compared with available data from JET on the threshold unstable MHD activity in toroidal confinement devices. In particular, questions arising as to Hartmans number and the selection of a kinematic viscosity are discussed.

Not Available

1992-11-01

333

Simulation of three-dimensional multi-phase flow characteristics in the deswirl section of the CDIF MHD power train  

SciTech Connect

A three-dimensional, two-phase, turbulent flow computer code was used to predict flow characteristics of seed particles and coal gas in the deswirl section of the CDIF MHD power train system. Seed material which has a great effect on the overall performance of the MHD system is injected in the deswirl against the swirling coal gas flow coming from the first stage combustor. While testing the MHD system, excessive seed material (70% more than theoretical value) was required to achieve design operating conditions. Calculations show that the swirling coal gas flow turns a 90 degree angle to minimize the swirl motion before entering a second stage combustor and many seed particles are too slow to react to the flow turning and deposit on the walls of the deswirl section. Some seed material deposited on the walls is covered by slag layer and removed from the gas flow. The reduction of seed material in the gas flow decreases MHD power generation significantly. A computational experiment was conducted and its results show that seed injection on the wall can be minimized by simply changing the seed injection and an optimum location was identified. If seed is injected from the location of choice, the seed deposition is reduced by a factor of 10 compared to the original case.

Chang, S.L.; Lottes, S.A.; Petrick, M.

1994-06-01

334

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

335

An 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 than 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. 3 figs., 5 tabs.

Berry, G.F.

1989-10-30

336

Time Variation of MHD Accretion onto a Black Hole.  

National Technical Information Service (NTIS)

Nonstationary and nonaxisymmetric perturbations of magnetohydrodynamic (MHD) accretion onto a Kerr black hole are studied. A small amplitude fluctuation of the electromagnetic field is regarded as a source of perturbations in a magnetosphere. How the plas...

K. Hirotani A. Tomimatsu M. Takahashi

1993-01-01

337

Electromagnetic pulse (EMP) interaction with electric power systems. Power Systems Technology Program. Final report  

Microsoft Academic Search

A high altitude nuclear burst, detonated at a height of 50 km or more, causes two types of electromagnetic pulses (EMP) - high altitude EMP (HEMP) and magnetohydrodynamic EMP (MHD-EMP). This high altitude EMP scenario is of principal concern when assessing the effects of EMP on electric power systems, because the total United States can be simultaneously illuminated by HEMP

Zaininger

1984-01-01

338

Electromagnetic pulse (EMP) interaction with electric power systems. Power Systems Technology Program  

Microsoft Academic Search

A high altitude nuclear burst, detonated at a height of 50 km or more, causes two types of electromagnetic pulses (EMP), high altitude EMP (HEMP) and magnetohydrodynamic EMP (MHD-EMP). This high altitude EMP scenario is of principal concern when assessing the effects of EMP on electric power systems, because the total United States can be simultaneously illuminated by HEMP and

H. W. Zaininger

1984-01-01

339

Shell models of magnetohydrodynamic turbulence  

NASA Astrophysics Data System (ADS)

Shell models of hydrodynamic turbulence originated in the seventies. Their main aim was to describe the statistics of homogeneous and isotropic turbulence in spectral space, using a simple set of ordinary differential equations. In the eighties, shell models of magnetohydrodynamic (MHD) turbulence emerged based on the same principles as their hydrodynamic counter-part but also incorporating interactions between magnetic and velocity fields. In recent years, significant improvements have been made such as the inclusion of non-local interactions and appropriate definitions for helicities. Though shell models cannot account for the spatial complexity of MHD turbulence, their dynamics are not over simplified and do reflect those of real MHD turbulence including intermittency or chaotic reversals of large-scale modes. Furthermore, these models use realistic values for dimensionless parameters (high kinetic and magnetic Reynolds numbers, low or high magnetic Prandtl number) allowing extended inertial range and accurate dissipation rate. Using modern computers it is difficult to attain an inertial range of three decades with direct numerical simulations, whereas eight are possible using shell models.In this review we set up a general mathematical framework allowing the description of any MHD shell model. The variety of the latter, with their advantages and weaknesses, is introduced. Finally we consider a number of applications, dealing with free-decaying MHD turbulence, dynamo action, Alfvén waves and the Hall effect.

Plunian, Franck; Stepanov, Rodion; Frick, Peter

2013-02-01

340

Solar-Powered Liquid-Metal MHD Performance and Cost Studies.  

National Technical Information Service (NTIS)

The two-phase-generator, liquid-metal magnetohydrodynamic (LMMHD) energy-conversion concept was initially developed at Argonne National Laboratory to meet the anticipated need for an energy-conversion system compatible with liquid metal-cooled heat source...

E. S. Pierson H. Herman

1981-01-01

341

Simulations Of 3D MHD Jets: The Effects Of ICM Weather And AGN History On X-ray Cavities  

Microsoft Academic Search

The powerful jets from AGN produce low density bubbles in the ICM of the host galaxy cluster that are observed as X-ray cavities. The morphology of X-ray cavities is influenced by factors such as AGN history and ICM weather. We present 3D magnetohydrodynamical (MHD) simulations of hypersonic AGN jets in realistic cluster environments that explore the relationship between these factors

Peter Mendygral; T. W. Jones; K. Dolag

2011-01-01

342

Magnetohydrodynamic Waves  

NASA Astrophysics Data System (ADS)

Magnetohydrodynamic waves are found in a wide variety of astrophysical plasmas. They have been measured in plasma fusion devices and detected in the MAGNETOSPHERE OF EARTH, the SOLAR WIND and a number of magnetic structures seen in the Sun's atmosphere. In space plasmas their detection is often indirect, by matching measured properties (such as propagation speed or pressure variation) with theore...

Roberts, B.; Murdin, P.

2000-11-01

343

MHD integrated topping cycle. Twenty-fifth quarterly technical progress report, August 1993--October 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) slagging 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

1994-10-01

344

MHD integrated topping cycle. Twenty-third quarterly technical progress report, February 1993--April 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) slagging 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

1994-10-01

345

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

346

Helical shell models for MHD  

NASA Astrophysics Data System (ADS)

A shell model for magnetohydrodynamics (MHD) is derived directly from the dynamical system driving the evolution of three helical modes interacting in a triad. The use of helical modes implies that two shell variables are required for the velocity as well as for the magnetic field. The advantage of the method is the automatic conservation of all the ideal quadratic MHD invariants. The number of coupling constants is however larger than in traditional shell models. This difficulty is worked around by introducing an averaging procedure that allows to derive the shell model coupling constants directly from the MHD equations. The resulting shell model is used to explore the influence of a helical forcing on the global properties of MHD turbulence close to the onset of the dynamo regime.

Lessinnes, T.; Plunian, F.; Carati, D.

2009-11-01

347

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

Microsoft Academic Search

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

R. J. Sovie

1976-01-01

348

Promising applications of the liquid metal MHD energy conversion technology  

Microsoft Academic Search

Applications of the liquid-metal MHD (magnetohydrodynamic) energy conversion technology that could benefit from its unique features are reviewed with emphasis on applications that might be realized in the relatively near future and on the OMACON (optimized magnetohydrodynamic conversion) concept. Included among the promising applications are cogeneration, energy recovery from industrial processes involving the use of molten metals, energy conversion from

H. Branover; A. El-Boher; E. Greenspan; A. Barak

1989-01-01

349

Pulsed magnetohydrodynamic generator with a superconducting magnetic system. [Translated from Russian  

SciTech Connect

An urgent need for creating independent sources of electric power capable of generating a power of tens or hundreds of megawatts in a few milliseconds has now emerged. A pulsed MHD generator, in which the conversion of mechanical energy of explosion products into electrical energy is accomplished, can serve as such a power source. There are published reports on testing of such MHD generators with ordinary magnetic systems. It seemed advisable to study the operation of a pulsed generator with a superconductive magnetic system in the overall plan of research on the creation of magnetohydrodynamic generators. The creation of a pulsed MHD generator with a superconductive magnetic system would make it possible to improve substantially the operational indicators of the installation and to ensure its continuous operation, regardless of the presence of additional power sources for feeding the magnet. The problem of creating an optimum generator and a magnetic system with the maximum acceptable field intensity was not raised in the first stage. The purpose of the work was to investigate the set of questions which arise in the joint use of a pulsed MHD generator and a superconductive magnetic system.

Kirillin, V.A.; Sheyndlin, A.Ye.; Asinovskiy, E.I.; Sychev, V.V.; Zenkevich, V.B.

1985-11-08

350

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

351

Gravitational radiation from primordial helical inverse cascade magnetohydrodynamic turbulence  

SciTech Connect

We consider the generation of gravitational waves by primordial helical inverse-cascade magnetohydrodynamic (MHD) turbulence produced by bubble collisions at the electroweak phase transition. We extend the previous study 1 by considering both currently discussed models of MHD turbulence. For popular electroweak phase transition parameter values, the generated gravitational wave spectrum is only weakly dependent on the MHD turbulence model. Compared with the unmagnetized electroweak phase transition case, the spectrum of MHD-turbulence-generated gravitational waves peaks at lower frequency with larger amplitude and can be detected by the proposed Laser Interferometer Space Antenna.

Kahniashvili, Tina [Department of Physics, Kansas State University, 116 Cardwell Hall, Manhattan, Kansas 66506 (United States); Department of Physics, Laurentian University, Ramsey Lake Road, Sudbury, ON P3E 2C6 (Canada); National Astrophysical Observatory, Ilia Chavchavadze State University, 2A Kazbegi Ave, Tbilisi, GE-0160 (Georgia); Campanelli, Leonardo [Dipartimento di Fisica, Universita di Bari, I-70126 Bari (Italy); INFN - Sezione di Bari, I-70126 Bari (Italy); Gogoberidze, Grigol [Department of Physics, Kansas State University, 116 Cardwell Hall, Manhattan, Kansas 66506 (United States); National Astrophysical Observatory, Ilia Chavchavadze State University, 2A Kazbegi Ave, Tbilisi, GE-0160 (Georgia); Centre for Plasma Astrophysics, K.U. Leuven, Celestijnenlaan 200B, 3001 Leuven (Belgium); Maravin, Yurii; Ratra, Bharat [Department of Physics, Kansas State University, 116 Cardwell Hall, Manhattan, Kansas 66506 (United States)

2008-12-15

352

Anomalous magnetohydrodynamics  

NASA Astrophysics Data System (ADS)

Anomalous symmetries induce currents which can be parallel rather than orthogonal to the hypermagnetic field. Building on the analogy of charged liquids at high magnetic Reynolds numbers, the persistence of anomalous currents is scrutinized for parametrically large conductivities when the plasma approximation is accurate. Different examples in globally neutral systems suggest that the magnetic configurations minimizing the energy density with the constraint that the helicity be conserved coincide, in the perfectly conducting limit, with the ones obtainable in ideal magnetohydrodynamics where the anomalous currents are neglected. It is argued that this is the rationale for the ability to extend to anomalous magnetohydrodynamics the hydromagnetic solutions characterized by finite gyrotropy. The generally covariant aspects of the problem are addressed with particular attention to conformally flat geometries which are potentially relevant for the description of the electroweak plasma prior to the phase transition.

Giovannini, Massimo

2013-09-01

353

Nonlinear Magnetohydrodynamics  

Microsoft Academic Search

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

V. Shafranov

1998-01-01

354

MHD can clean up the environment  

SciTech Connect

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) Coal-Fired Flow Facility (CFFF), located at the University of Tennessee Space Institute (UTSI). Some of the attractive features of MHD include: A potential for increasing overall plant efficiency to 60% as compared to <40% for conventional power plants. Provision of built-in controls to eliminate/reduce the emissions of acid rain precursors, such as SO{sub 2} and NO{sub x} well below the existing New Source Performance Standards (NSPS) and Clean Air Act requirements. Provision of adequate particulate resistivity for easy and efficient capture of submicron sized panicles in dry and wet electrostatic precipitators. Provision of built-in control to eliminate/reduce the Cl{sub 2}/HCl emission problems common to waste incinerators. Producing nearly zero emissions of priority pollutants (inorganics as well as organics on a pound per pound of coal basis) in comparison to conventional coal-fired facilities. Environmentally acceptable solid and liquid waste streams, and release of less CO{sub 2} (a suspected greenhouse gas) per unit of electricity generated than the conventional power plant due to the increased efficiency.

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

1993-03-01

355

MHD can clean up the environment  

SciTech Connect

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) Coal-Fired Flow Facility (CFFF), located at the University of Tennessee Space Institute (UTSI). Some of the attractive features of MHD include: A potential for increasing overall plant efficiency to 60% as compared to <40% for conventional power plants. Provision of built-in controls to eliminate/reduce the emissions of acid rain precursors, such as SO[sub 2] and NO[sub x] well below the existing New Source Performance Standards (NSPS) and Clean Air Act requirements. Provision of adequate particulate resistivity for easy and efficient capture of submicron sized panicles in dry and wet electrostatic precipitators. Provision of built-in control to eliminate/reduce the Cl[sub 2]/HCl emission problems common to waste incinerators. Producing nearly zero emissions of priority pollutants (inorganics as well as organics on a pound per pound of coal basis) in comparison to conventional coal-fired facilities. Environmentally acceptable solid and liquid waste streams, and release of less CO[sub 2] (a suspected greenhouse gas) per unit of electricity generated than the conventional power plant due to the increased efficiency.

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

1993-01-01

356

Micromachined magnetohydrodynamic actuators and sensors  

US Patent & Trademark Office Database

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)

2000-11-14

357

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

358

MHD simple waves and the divergence wave  

NASA Astrophysics Data System (ADS)

In this paper we investigate magnetohydrodynamic (MHD) simple divergence waves in MHD, for models in which ?.B?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 ?.B?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 J. We consider the form of the MHD equations used by both Powell et al. [1] and Janhunen [2]. 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.; Pogorelov, N. V.; Zank, G. P.

2010-03-01

359

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

360

Gravitational Radiation from Primordial Helical MHD Turbulence  

Microsoft Academic Search

We consider gravitational waves (GWs) generated by primordial inverse-cascade\\u000ahelical magneto-hydrodynamical (MHD) turbulence produced by bubble collisions\\u000aat the electroweak phase transitions (EWPT). Compared to the unmagnetized EWPT\\u000acase, the spectrum of MHD-turbulence-generated GWs peaks at lower frequency\\u000awith larger amplitude and can be detected by the proposed Laser Interferometer\\u000aSpace Antenna (LISA).

Tina Kahniashvili; Grigol Gogoberidze; Bharat Ratra

2008-01-01

361

Magnetohydrodynamic mixed convection of a power-law fluid past a stretching surface in the presence of thermal radiation and internal heat generation\\/absorption  

Microsoft Academic Search

The problem of magneto-hydrodynamic mixed convective flow and heat transfer of an electrically conducting, power-law fluid past a stretching surface in the presence of heat generation\\/absorption and thermal radiation has been analyzed. After transforming the governing equations with suitable dimensionless variables, numerical solutions are generated by an implicit finite-difference technique for the non-similar, coupled flow. The solution is found to

Chien-Hsin Chen

2009-01-01

362

MESSENGER Observations of Magnetohydrodynamic Waves in the Solar Corona from Faraday Rotation  

NASA Astrophysics Data System (ADS)

During the declining phase of the longest solar minimum in a century, the arrival of the MESSENGER spacecraft at superior conjunction allowed the measurement of magnetohydrodynamic (MHD) waves in the solar corona with its 8 GHz radio frequency signal. MHD waves crossing the line of sight were measured via Faraday rotation fluctuations (FRFs) in the plane of polarization (PP) of MESSENGER's signal. FRFs in previous observations of the solar corona (at greater offset distances) consisted of a turbulent spectrum that decreased in power with increasing frequency and distance from the Sun. Occasionally a spectral line, a distinct peak in the power spectral density spectrum around 4 to 8 mHz, was also observed in these early data sets at offset distances of about 5 to 10 solar radii. The MESSENGER FRF data set shows a spectral line at an offset distance between 1.55 to 1.85 solar radii with a frequency of 0.6±0.2 mHz. Other possible spectral lines may be at 1.2, 1.7, and 4.5 mHz; MHD waves with these same frequencies have been observed in X-ray data traveling along closed coronal loops at lower offset distances. An initial analysis of the MESSENGER spectral line(s) shows behavior similar to turbulent spectra: decreasing power with increasing frequency and distance from the Sun. Here we detail the steps taken to process the MESSENGER change in PP data set for the MHD wave investigation.

Jensen, E. A.; Nolan, M.; Bisi, M. M.; Chashei, I.; Vilas, F.

2013-07-01

363

Observation of a strange MHD phenomenon on EAST tokamak  

NASA Astrophysics Data System (ADS)

A strange magnetohydrodynamic (MHD) phenomenon has been observed on EAST tokamak. The waveform of the MHD oscillations is similar to that of fishbone mode. The observation and analyzing results suggest that the appearance of the strange oscillations is associated with intensive impurity radiation.

Chen, Kaiyun; Hu, Liqun; Chen, Yebin; Ma, Tianpeng; Duan, Yanmin

2010-04-01

364

Analysis of MHD Interstellar Turbulence using Tsallis Statistics  

Microsoft Academic Search

In an effort to characterize interstellar magneto-hydrodynamic (MHD) turbulence, we study probability distribution functions (PDFs) of spacial increments of density, velocity, and magnetic field strength for fourteen three dimensional ideal isothermal MHD simulations. We fit the PDFs using the Tsallis function and study the fit parameters dependence on the compressibility and magnetization of the gas. For three dimensional density, column

Benjamin M. Tofflemire; A. Lazarian; B. Burkhart

2011-01-01

365

HALL-MHD turbulence in the Solar atmosphere  

Microsoft Academic Search

When the velocity field of a magneto-fluid is accorded an intrinsically equal status with the magnetic field, standard magnetohydrodynamics (MHD) must be replaced by the dispersive or Hall MHD which retains some crucial two-fluid effects, in particular the physics on the ion skin depth scale. The larger system has three quadratic invariants: the generalized helicity (a sum of the cross

V. Krishan; S. M. Mahajan

2004-01-01

366

Astrophysics without Gravity: When the Lorentz Force (MHD) Dominates  

Microsoft Academic Search

Magnetohydrodynamics (MHD) is sometimes conceived of as hydrodynamics with the Lorentz force added as an extra term. This way of thinking oversimplifies matters however, because MHD not only includes a new force, but also includes the constraint that magnetic flux is frozen into the fluid frame. The combination of the new force and the new constraint results in processes that

Paul M. Bellan

2010-01-01

367

Acoustical gas core reactor with MHD power generation for burst power in a bimodal system  

Microsoft Academic Search

Research is being conducted on gas core reactors for space nuclear power to establish the scientific feasibility and engineering validation of a reactor and energy conversion system that can significantly improve specific power, dynamic performance and system efficiency. Rapid achievement of burst mode (GWe) operation at core power densities of 1 kW\\/mL and reactor masses of a kg\\/MWt are research

E. T. Dugan; A. M. Jacobs; C. C. Oliver; W. E. Lear Jr.

1987-01-01

368

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

369

Magnetohydrodynamic tokamak plasma edge stability  

NASA Astrophysics Data System (ADS)

The edge of a tokamak plasma is interesting due to its geometrical structure that is difficult to model mathematically and computationally, its tendency to form ‘transport barriers’ with increased confinement of energy and momentum, and the edge-localized instabilities associated with transport barriers that threaten the lifetime of components in large tokamaks. Ideal magnetohydrodynamics (MHD) is generally well understood, but only in the past decade has a good theoretical understanding emerged of MHD stability near the plasmas' separatrix when one or more X-points are present. By reviewing and discussing our theoretical understanding of ideal MHD stability of the plasma's edge, a clear picture emerges for its ideal stability. Conclusions are: ideal MHD will limit the width of strong transport barriers at the plasma's edge, a strong edge transport barrier will be associated with ELMs, ELMs will have a maximum toroidal mode number, will be preceded by smaller precursor instabilities, and can be triggered by sufficient changes to either the edge or the core plasma. Observations are made for the mechanisms responsible for edge transport barriers and ELMs, some leading to experimental predictions, others highlighting important open questions.

Webster, Anthony J.

2012-11-01

370

Free boundary skin current MHD (magnetohydrodynamic) equilibria  

SciTech Connect

Function theoretic methods in the complex plane are used to develop simple parametric hodograph formulae which generate sharp boundary equilibria of arbitrary shape. The related method of Gorenflo and Merkel is discussed. A numerical technique for the construction of solutions, based on one of the methods is presented. A study is made of the bifurcations of an equilibrium of general form. 28 refs., 9 figs.

Reusch, M.F.

1988-02-01

371

MHD Coronal Seismology  

NASA Astrophysics Data System (ADS)

The presence of oscillations in solar coronal structures has been known for more than seventy years. Observational reports about the presence of oscillatory motions in solar filaments go back to 1930 while in the case of other coronal structures (loops, plumes, etc) direct evidence has been recently obtained thanks to the detailed observations made by SoHO and TRACE. Due to these satellites, as well as to ground-based observations, evidence of magnetohydrodynamic (MHD) waves in the solar corona has risen dramatically. MHD coronal seismology provides with an indirect path to determine the physical conditions and parameters of the solar corona [coronal magnetic field, transport coefficients (viscosity, resistivity, thermal conductivity, etc.), heating function, filling factors] which are difficult to measure accurately. In essence, it is similar to the acoustic diagnostic of the solar interior (Helioseismology) and to MHD spectroscopy used to determine physical parameters of laboratory plasmas. In spite that there are many solar coronal structures in which oscillations have been detected (prominences, loops, plumes, coronal holes, etc.), in the following we will concentrate in prominences and coronal loops trying to summarize part of our current knowledge about their oscillations as well as about the theoretical models developed to explain those oscillations in terms of MHD waves.

Ballester, J. L.

2007-03-01

372

Nonlinear magnetohydrodynamical effects in precessional fishbone oscillations  

NASA Astrophysics Data System (ADS)

The role of magnetohydrodynamic nonlinearities in precessional m=n=1 fishbone oscillations has been analyzed analytically and numerically. The work is based on the reduced magnetohydrodynamic (MHD) equations including a linear energetic particle drive model. When the energetic particle pressure is close to the instability threshold, the top-hat linear eigenmode profile of the ideal MHD m=1 radial displacement splits up into a two-step structure around the q=1 flux surface, due to the finite frequency ? of the mode. The width of the individual steps is a factor ?/? smaller than the distance between them, where ? is the growth rate of the mode. We find that the MHD nonlinearities modify the mode structure further, and produce explosive nonlinear growth, accompanied by frequency chirping, for modes that are near the instability threshold. The results are quite different for fishbone oscillations that are excited well above the stability threshold. The growth rates of these linearly fast growing modes decreases nonlinearly and the MHD nonlinearities are stabilizing in this limit. The nonlinear MHD effects are important when the plasma displacement is comparable to, or larger than, the scale length of the fishbone structure.

Ödblom, A.; Breizman, B. N.; Sharapov, S. E.; Hender, T. C.; Pastukhov, V. P.

2002-01-01

373

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

374

Spectral modeling of magnetohydrodynamic turbulent flows.  

PubMed

We present a dynamical spectral model for large-eddy simulation of the incompressible magnetohydrodynamic (MHD) equations based on the eddy damped quasinormal Markovian approximation. This model extends classical spectral large-eddy simulations for the Navier-Stokes equations to incorporate general (non-Kolmogorovian) spectra as well as eddy noise. We derive the model for MHD flows and show that the introduction of an eddy damping time for the dynamics of spectral tensors, in the absence of equipartition between the velocity and magnetic fields, leads to better agreement with direct numerical simulations, an important point for dynamo computations. PMID:18850939

Baerenzung, J; Politano, H; Ponty, Y; Pouquet, A

2008-08-29

375

Spontaneous non-steady reconnection within the framework of pure resistive magnetohydrodynamics: is anomalous resistivity really unescapable?  

NASA Astrophysics Data System (ADS)

Can pure resistive magnetohydrodynamics reconnection within the solar environment be spontaneously fast and determine a final macroscopic turbulent state? Yes, it can. Several numerical experiments as well as analytical studies have suggested that within the pure resistive magnetohydrodynamics (MHD) framework it is not possible to have a magnetic field-line reconnecting dynamics that spontaneously evolves from a low and constant rate phase to a fast and high power regime. "Ad-hoc" terms derived from kinetic theory are used to resemble heuristically the non-trivial microscopic mechanisms determining the formation of an anomalous enhancement in plasma’s local resistivity that in turn triggers a fast MHD reconnection process. Here, we present both the complete numerical and geometrical analysis of the spontaneous non-steady MHD reconnection mechanism first discovered by Lapenta (2008) and the application of such model to the instability evolution of a current-sheet located in a medium with a strong density variation along the current layer. Hence, the effects of the global resistivity, the global viscosity and the plasma beta on the overall dynamics are considered. Such mechanism allows the transition from a slow to a self-feeding fast reconnection regime in MHD and it determines a final chaotic structure in a current-sheet whose global dynamics resembles the tearing evolution of solar structures both just before and immediately after observed and/or modeled explosive and bursty phenomena. Although we can not neglect the importance of anomalous effects to connect the small- and large-scale dynamics of plasma structures with the MHD-theory framework, the mechanism here presented would allow us to develop a consistent model for fast MHD reconnection within the solar environment.

Bettarini, L.; Skender, M.; Lapenta, G.

2009-12-01

376

Electromagnetic pulse and the electric power network  

SciTech Connect

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 electric power systems are discussed, and an overview of the Department of Energy (DOE) EMP research program is presented.

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

1984-01-01

377

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.

378

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

379

Second generation of a rotational electrochemical seismometer using magnetohydrodynamic technology  

NASA Astrophysics Data System (ADS)

Rotational seismometers have many applications. Some require a low self noise with a lower clip specification. Others require many different bandpass specifications, from very low to higher frequencies. The principles of the eentec second-generation R-2 electrochemical triaxial rotational seismometer can achieve many features for various applications. Combining the use of the sophisticated magnetohydrodynamic (MHD) technology increases the current and future features. Principles of the MHD technology used and the many advantages it has in a rotational seismometers are described.

Leugoud, Robert; Kharlamov, Alexei

2012-10-01

380

Theory of magnetohydrodynamic instabilities excited by energetic particles in tokamaks  

Microsoft Academic Search

The resonant excitations of high-n magnetohydrodynamic (MHD) instabilities by the energetic ions\\/alpha particles in tokamaks are theoretically analyzed. Here, n is the toroidal mode number. Since, typically, the MHD modes consist of two-scale structures; one singular (‘‘inertial’’) region and one regular (ideal) region, the energetic particle contributions in the singular region are suppressed by the finite-size orbits. Analytical dispersion relations

Liu Chen

1994-01-01

381

MHD Shocks in Coronal Mass Ejections.  

National Technical Information Service (NTIS)

The primary objective of this research program is the study of the magnetohydrodynamic (MHD) shocks and nonlinear simple waves produced as a result of the interaction of ejected lower coronal plasma with the ambient corona. The types of shocks and nonline...

R. S. Steinolfson

1991-01-01

382

Closed cycle MHD for central station power with fossil or nuclear fuels  

Microsoft Academic Search

A closed--cycle MHD generator using a noble gas with alkali metal vapor ; as the working fiuid, when used as a topping unit for a conventional steam plant, ; can yield cycle efficiencies in excess Of 60% at peak stagnation temperature of ; 3000 deg F. While high enough for substantial gains in thermodynamic efficiency, ; this temperature is relatively

B. Zauderer; C. H. Marston; C. S. Cook

1973-01-01

383

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

384

High-temperature inert gas plasma magnetohydrodynamic energy conversion by using linear-shaped Faraday-type channel  

NASA Astrophysics Data System (ADS)

We describe high-density magnetohydrodynamic (MHD) energy conversion in a high-temperature seed-free argon plasma, for which a compact linear-shaped Faraday-type MHD electrical power generator is used. Short-time-duration single-pulse shock-tunnel-based experiments demonstrate the MHD energy conversion with varying total inflow temperature up to 9000 K and applied magnetic-flux density up to 4.0 T. The high-temperature plasma is transformed from the thermal-equilibrium state at the entrance to the weak-nonequilibrium state in the supersonic MHD channel. The discharge structure is reasonably homogeneous without suffering from serious streamer development. The power generation performance is monotonically improved by increasing total inflow temperature and strength of magnetic field. The enthalpy extraction efficiency of 13.1% and overall power density of 0.16 GW/m3 are attained. The local power density at the middle of the channel reaches 0.24 GW/m3.

Murakami, Tomoyuki; Zhuang, Yunqin; Okuno, Yoshihiro

2013-02-01

385

Stationary Two-Dimensional Magnetohydrodynamic Flows with Shocks: Characteristic Analysis and Grid Convergence Study  

Microsoft Academic Search

Five model flows of increasing complexity belonging to the class of stationary two-dimensional planar field-aligned magnetohydrodynamic (MHD) flows are presented which are well suited to the quantitative evaluation of MHD codes. The physical properties of these five flows are investigated using characteristic theory. Grid convergence criteria for flows belonging to this class are derived from characteristic theory, and grid convergence

H. De Sterck; A. Cs??k; D. Vanden Abeele; S. Poedts; H. Deconinck

2001-01-01

386

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

387

Weakly Compressible Magnetohydrodynamic Turbulence in the Solar Wind and the Interstellar Medium  

Microsoft Academic Search

A new four--eld system of equations is derived from the compressible magnetohydrodynamic (MHD) equations for low Mach number turbulence in the solar wind and the interstellar medium, permeated by a spatially varying magnetic -eld. The plasma beta is assumed to be of order unity or less. It is shown that the full MHD equations can be reduced rigorously to a

A. Bhattacharjee; C. S. Ng; S. R. Spangler

1998-01-01

388

Resistive magnetohydrodynamic studies of tearing mode instability with equilibrium shear flow and magnetic reconnection  

Microsoft Academic Search

Magnetic reconnection and tearing can play an important role in fusion experiments and in space plasmas. The magnetohydrodynamic (MHD) study of the linear and nonlinear evolution of the resistive tearing mode instability in the presence of equilibrium shear flow, and the reconnection of an x-point magnetic field configuration are discussed. Numerical solutions of the linearized time-dependent MHD equations and growth

Leon Ofman

1992-01-01

389

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

390

Leaky waveguide model for MHD-wave-driven/winds from coronal holes  

SciTech Connect

Magnetohydrodynamic (MHD) waves, driven by the large-scale convective motions of the photosphere are suggested as a possible source of additional acceleration for the stellar wind. Most of the turbulent power in a coronal hole is carried by MHD waves with periods of a few hundred seconds or longer. This is evident from direct observations of turbulence in the solar photosphere, as well as in-situ observations of turbulence in the solar wind. But waves with periods this long have wavelengths which are typically as large as the transverse scale of the coronal hole flux tube itself. For these waves boundary effects are important and the coronal hole must be treated as a waveguide. The propagation of MHD waves using this waveguide approach is discussed. The simple model presented demonstrates that coronal holes can act as waveguides for MHD waves. For typical solar parameters the waves are compressible and can generate a wave tensile force which tends to cancel at least part of the wave pressure force. This effect tends to decrease the efficiency of MHD wave acceleration.

Davila, J.M.

1985-01-01

391

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

392

Development Program for MHD Direct Coal Fired Power Generation Test Facility. Annual Technical Progress Report, January--December 1977.  

National Technical Information Service (NTIS)

Tests conducted in the existing MHD facility supported areas critical to the design of test components for the new intermediate-size, direct coal fired MHD development facility. Experimental results provided evidence as to what the flow train downstream o...

J. B. Dicks H. P. Markant R. C. Attig

1978-01-01

393

Key contributions in MHD power generation. Quarterly technical progress report, June 1-August 31, 1980  

SciTech Connect

Activities are reported in detail. The tasks reported on 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. Work reported includes discussion of experiments in the arc damage facility and in the 3 MW Simulation Facility. A theory is presented which permits calculation of the voltage-shorting current of a sidewall element, as a function of near-wall voltage drops and geometry. Progress on the application of Langmuir probe diagnostics for the study of the quantitative effects of small-scale turbulence on MHD plasma properties is reported. In addition, calculations of Hall field breakdown for insulating walls are discussed. Additional stacks of electrodes of super-hot-wall design were fabricated and assembled. A computer model is presented for the simulation of coal combustion under conditions pertinent to single-stage and two-stage open-cycle MHD systems. A parametric study of the effects of pressure, fuel/air equivalence ratio, and oxidant preheat temperature is used to illustrate tradeoffs between coal combustion efficiency, ash vaporization, and combustor residence time. Also a recently developed computer code for calculating the flow dynamics of constant density flow in the second-stage trumpet-shaped nozzle section of a two-stage MHD swirl combustor for application to a disk generator is described. (WHK)

Louis, J.F.

1981-07-01

394

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

Microsoft Academic Search

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

R. J. Sovie

1977-01-01

395

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

Microsoft Academic Search

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

R. J. Sovie

1977-01-01

396

Scattering of cosmic rays by magnetohydrodynamic interstellar turbulence.  

PubMed

Recent advances in understanding of magnetohydrodynamic (MHD) turbulence call for substantial revisions in our understanding of cosmic ray transport. We use recently obtained scalings of MHD modes to calculate the scattering frequency for cosmic rays. We consider gyroresonance with MHD modes (Alfvénic, slow, and fast) and transit-time damping by fast modes. We conclude that the gyroresonance with fast modes is the dominant contribution to cosmic ray scattering for the typical interstellar conditions. In contrast to earlier studies, we find that Alfvénic and slow modes are inefficient because they are far from the isotropy usually assumed. PMID:12513130

Yan, Huirong; Lazarian, A

2002-12-27

397

The rebirth of MHD  

NASA Astrophysics Data System (ADS)

A low-temperature MHD system employing liquid metal and a low-boiling point organic vapor as its working fluids is described, and considered from the standpoints of: (1) development status; (2) thermal energy sources, with emphasis on low-temperature solar collectors and industrial process waste heat; (3) economic advantage, by comparison to Rankine-cycle and photovoltaic solar systems; and (4) operational efficiency. Figures for the net cost of power produced by the three solar systems compared, when the further conversion of MHD exhaust heat is considered, are $0.57/kWh for the photovoltaic, $0.116/kWh for the Rankine cycle, and $0.054/kWh for the low-temperature MHD. A further contrast is drawn with the typically 2500 C-working gas MHD systems being developed in the U.S. and U.S.S.R.

Edelhart, M.; Greenfield, A.

1982-02-01

398

Conceptual design of a coal-fired MHD retrofit plant. Topical report, Seed Regeneration System Study 2  

SciTech Connect

Westinghouse Advanced Energy Systems (WAES), through Contract No. DE-AC22-87PC79668 funded by US DOE/PETC, is conducting a conceptual design study to evaluate a coal-fired magnetohydrodynamic (MHD) retrofit of a utility plant of sufficient size to demonstrate the technical and future economic viability of an MHD system operating within an electric utility environment. The objective of this topical report is to document continuing seed regeneration system application studies and the definition of will system integration requirements for the Scholz MHD retrofit plant design. MHD power plants require the addition of a seeding material in the form of potassium to enhance the ionization of the high temperature combustion gas in the MHD channel. This process has an added environmental advantage compared to other types of coal-fired power plants in that the potassium combines with the naturally occurring sulfur in the coal to form a potassium sulfate flyash (K{sub 2}SO{sub 4}) which can be removed from the process by appropriate particulate control equipment. Up to 100% of the Sulfur in the coal can be removed by this process thereby providing environmentally clean power plant operation that is better than required by present and anticipated future New Source Performance Standards (NSPS).

Not Available

1992-11-01

399

Characteristics of pulsed magnetohydrodynamic generators with two-phase combustion product flow  

Microsoft Academic Search

The paper examines the effect of two-phase flow of combustion products on the operation of pulsed magnetohydrodynamic (MHD) generators. Experimental data are presented on the erosion of MHD walls resulting from the two-phase flow; the measurements of heat fluxes affecting the movement of Al2O3 films on MHD walls are given. The effects of the Al2O3 film on electric and physical

R. V. Dogadaev; L. A. Bukhteev; N. V. Lobanov; B. A. Tikhonov; A. A. Iakushev

1980-01-01

400

Subgrid-scale modeling of compressible magnetohydrodynamic turbulence in heat-conducting plasma  

SciTech Connect

A large-eddy simulation (LES) approach for compressible magnetohydrodynamic (MHD) turbulence in heat-conducting plasma is developed for the first time. Subgrid-scale models for new terms appearing due to the presence of magnetic field are suggested. Results of modeling for decaying compressible MHD turbulence are presented. Comparison and testing with results obtained by direct numerical simulation are made. The efficiency of the developed LES technique for compressible MHD turbulence in heat-conducting plasma is shown.

Chernyshov, A. A.; Karelsky, K. V.; Petrosyan, A. S. [Theoretical Section, Space Research Institute of the Russian Academy of Sciences, Profsoyuznaya 84/32, 117997 Moscow (Russian Federation)

2006-10-15

401

Modeling of diamagnetic stabilization of ideal magnetohydrodynamic instabilities associated with the transport barrier  

Microsoft Academic Search

A new code, MISHKA-D (Drift MHD), has been developed as an extension of the ideal magnetohydrodynamics (MHD) code MISHKA-1 in order to investigate the finite gyroradius stabilizing effect of ion diamagnetic drift frequency, omega*i, on linear ideal MHD eigenmodes in tokamaks in general toroidal geometry. The MISHKA-D code gives a self-consistent computation of both stable and unstable eigenmodes with eigenvalues

G. T. A. Huysmans; S. E. Sharapov; A. B. Mikhailovskii; W. Kerner

2001-01-01

402

Modeling of diamagnetic stabilization of ideal magnetohydrodynamic instabilities associated with the transport barrier  

Microsoft Academic Search

A new code, MISHKA-D (Drift MHD), has been developed as an extension of the ideal magnetohydrodynamics (MHD) code MISHKA-1 in order to investigate the finite gyroradius stabilizing effect of ion diamagnetic drift frequency, ?*i, on linear ideal MHD eigenmodes in tokamaks in general toroidal geometry. The MISHKA-D code gives a self-consistent computation of both stable and unstable eigenmodes with eigenvalues

G. T. A. Huysmans; S. E. Sharapov; A. B. Mikhailovskii; W. Kerner

2001-01-01

403

MHD direct channel from heat to electricity  

NASA Astrophysics Data System (ADS)

The potential benefits and difficulties of the development and operation of a combined MHD/steam electric generating plant are assessed. The concept of MHD power generation by the passage of extremely hot, pressurized coal combustion gases ionized by a seeding material through the field of a superconducting magnet, coupled with conventional steam generation using the MHD exhaust gases as a heat source, is outlined, and areas of MHD technology requiring extensive development are indicated. Recent research on these areas is reviewed, and achievements in MHD channel durability, superconducting magnets, power inverters and the planned start-up of a 40-50 MW component development and integration facility are noted. Development strategies to ensure the competitiveness of MHD with other advanced power systems are discussed, and means of ensuring reliability are indicated. The economic potential of MHD is considered, and it is noted that MHD may also be coupled with future fusion and high-temperature nuclear reactors.

Lihach, N.

1980-04-01

404

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

405

Ideal Magnetohydrodynamics Stability Spectrum with a Resistive Wall.  

National Technical Information Service (NTIS)

We show that the eigenvalue equations describing a cylindrical ideal magnetohydrodynamics (MHD) plasma interacting with a thin resistive wall can be put into the standard mathematical form: Alpha.X = lambdaB.X. This is accomplished by using a finite eleme...

S. C. Jardin S. P. Smith

2008-01-01

406

Feasibility of a MHD generator as a transmitter for electromagnetic sounding of the earth. [Mathematical models  

SciTech Connect

Development of a high-intensity source for use in time-domain electromagnetic (TDEM) soundings would permit investigation of geothermal systems to much greater depth than is now possible with controlled-source methods. The development of such a source is critically dependent upon a powerful, mobile generator. Magnetohydrodynamic pulse generators satisfy the weight and power requirements for such a generator. However, existing MHD generators which are used in geophysical applications are solid fueled, and therefore, very expensive to operate. Moreover, the pulse length from such a generator is limited to about 10 seconds, which may be too short to permit the maximum advantage to be gained from the available power. The shortcomings of the MHD generator will be remedied in a liquid-fueled generator now under development for the U.S. Air Force. A field program designed to compare available conventional and MHD generators would provide the necessary information for final generator selection, as well as an abundance of information on the nature of geothermal systems at depth. Operation and cost studies on MHD generators are given, and model calculations for TDEM soundings of geothermal hot-dry-rock systems are presented.

Fleming, D.B.

1976-08-10

407

Feasibility of MHD submarine propulsion. Phase II, MHD propulsion: Testing in a two Tesla test facility  

Microsoft Academic Search

This report describes the work performed during Phase 1 and Phase 2 of the collaborative research program established between Argonne National Laboratory (ANL) and Newport News Shipbuilding and Dry Dock Company (NNS). Phase I of the program focused on the development of computer models for Magnetohydrodynamic (MHD) propulsion. Phase 2 focused on the experimental validation of the thruster performance models

E. D. Doss; W. C. Sikes

1992-01-01

408

Solar-MHD energy conversion system. [tower focus collector with closed-cycle MHD generator  

Microsoft Academic Search

A solar energy conversion system includes a centrally positioned tower supporting a solar receiver, and an array of pivotally mounted reflectors disposed circumferentially therearound which reflect earth incident solar radiation onto the receiver which thermally excites and photo-ionizes a working fluid to form a plasma. The plasma is accelerated and further heated through a ceramic turbo-compressor into a magnetohydrodynamic (MHD)

Rathbun

1978-01-01

409

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

410

DYNAMIC ALIGNMENT AND EXACT SCALING LAWS IN MAGNETOHYDRODYNAMIC TURBULENCE  

SciTech Connect

Magnetohydrodynamic (MHD) turbulence is pervasive in astrophysical systems. Recent high-resolution numerical simulations suggest that the energy spectrum of strong incompressible MHD turbulence is E(k{sub perpendicular}) {proportional_to} k {sup -3/2}{sub perpendicular}. So far, there has been no phenomenological theory that simultaneously explains this spectrum and satisfies the exact analytic relations for MHD turbulence due to Politano and Pouquet. Indeed, the Politano-Pouquet relations are often invoked to suggest that the spectrum of MHD turbulence instead has the Kolmogorov scaling -5/3. Using geometrical arguments and numerical tests, here we analyze this seeming contradiction and demonstrate that the -3/2 scaling and the Politano-Pouquet relations are reconciled by the phenomenon of scale-dependent dynamic alignment that was recently discovered in MHD turbulence.

Boldyrev, Stanislav [Department of Physics, University of Wisconsin at Madison, 1150 University Ave, Madison, WI 53706 (United States); Mason, Joanne; Cattaneo, Fausto [Department of Astronomy and Astrophysics, University of Chicago, 5640 S. Ellis Ave, Chicago, IL 60637 (United States)], E-mail: boldyrev@wisc.edu, E-mail: jmason@flash.uchicago.edu, E-mail: cattaneo@flash.uchicago.edu

2009-07-01

411

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

NASA Astrophysics Data System (ADS)

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.

1980-02-01

412

Supersonic regime of the Hall-magnetohydrodynamics resistive tearing instability  

NASA Astrophysics Data System (ADS)

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; Ramos, Jesús J.

2012-07-01

413

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

414

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

415

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

416

Global Thermodynamic MHD Modeling of the Solar Corona in the Context of SDO/AIA Observations.  

NASA Astrophysics Data System (ADS)

Realistic magnetohydrodynamic (MHD) models can serve as powerful testbeds for exploring our understanding of magnetic and thermodynamic processes in the solar corona. An important aspect in their development is the use of observations to characterize model results. In this context we investigate the comparison of observations from the Atmospheric Imaging Assembly (AIA) onboard the Solar Dynamics Observatory (SDO) to a thermodynamic MHD model of the global corona (Lionello et al. 2009), with emphasis on exploiting the unique multi-spectral information available from the AIA observing program. We discuss the implications towards modeling multi-temperature magnetic structures observed in the low corona, and focus on the sensitivity of the AIA observables with respect to the choice of coronal heating parameterizations and magnetic boundary data. Research Supported by NASA and NSF.

Downs, Cooper; Linker, J. A.; Mikic, Z.; Lionello, R.; Riley, P.

2012-05-01

417

Weakly nonlinear magnetohydrodynamic wave interactions  

SciTech Connect

Equations describing weakly nonlinear magnetohydrodynamic (MHD) wave interactions in one Cartesian space dimension are discussed. For wave propagation in uniform media, the wave interactions of interest consist of: (a) three-wave resonant interactions in which high frequency waves, may evolve on long space and time scales if the wave phases satisfy the resonance conditions; (b) Burgers self-wave steepening for the magnetoacoustic waves, and (c) mean wave field effects, in which a particular wave interacts with the mean wave field of the other waves. For wave propagation in non-uniform media, further linear wave mixing terms appear in the equations. The equations describe four types of resonant triads: slow-fast magnetosonic wave interaction; Alfv{acute e}n-entropy wave interaction; Alfv{acute e}n-magnetosonic wave interaction; and magnetosonic-entropy wave interaction. The formalism is restricted to coherent wave interactions. {copyright} {ital 1999 American Institute of Physics.}

Webb, G.M. [Lunar and Planetary Laboratory, University of Arizona, Tucson, Arizona 85721 (United States); Brio, M.; Kruse, M.T. [Department of Mathematics, University of Arizona, Tucson, Arizona 85721 (United States); Zank, G.P. [Bartol Research Institute, University of Delaware, Newark, Delaware 19716 (United States)

1999-06-01

418

Solar-powered liquid-metal MHD performance and cost studies  

SciTech Connect

The two-phase-generator, liquid-metal magnetohydrodynamic (LMMHD) energy-conversion concept was initially developed at Argonne National Laboratory to meet the anticipated need for an energy-conversion system compatible with liquid metal-cooled heat sources, such as the liquid-metal fast breeder reactor (LMFBR) and the controlled thermonuclear reactor (CTR). In particular, the use of two working fluids, a thermodynamic fluid (gas or vapor) and an electrodynamic fluid (liquid metal) to provide the electrical conductivity, gives LMMHD great versatility in coupling to differing heat-source temperatures and meeting material constraints, e.g., heat addition can be to the liquid metal, the gas or vapor, or both. Three LMMHD versions are under investigation.

Pierson, E.S.; Herman, H.

1981-01-01

419

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

420

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

421

Diffusive Acceleration of Particles at Oblique, Relativistic, Magnetohydrodynamic Shocks  

NASA Astrophysics Data System (ADS)

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.; Baring, Matthew G.

2012-01-01

422

Benchmark solutions for MHD solver development  

NASA Astrophysics Data System (ADS)

A benchmark solution is of great importance in validating algorithms and codes for magnetohydrodynamic (MHD) flows. Hunt and Shercliff's solutions are usually employed as benchmarks for MHD flows in a duct with insulated walls or with thin conductive walls, in which wall effects on MHD are represented by the wall conductance ratio. With wall thickness resolved, it is stressed that the solution of Sloan and Smith's and the solution of Butler's can be used to check the error of the thin wall approximation condition used for Hunt's solutions. It is noted that Tao and Ni's solutions can be used as a benchmark for MHD flows in a duct with wall symmetrical or unsymmetrical, thick or thin. When the walls are symmetrical, Tao and Ni's solutions are reduced to Sloan and Smith's solution and Butler's solution, respectively.

Tao, Zhen; Ni, MingJiu

2013-02-01

423

Nonlinear ideal magnetohydrodynamics instabilities  

SciTech Connect

Explosive phenomena such as internal disruptions in toroidal discharges and solar flares are difficult to explain in terms of linear instabilities. A plasma approaching a linear stability limit can, however, become nonlinearly and explosively unstable, with noninfinitesimal perturbations even before the marginal state is reached. For such investigations, a nonlinear extension of the usual MHD (magnetohydrodynamic) energy principle is helpful. (This was obtained by Merkel and Schlueter, Sitzungsberichted. Bayer. Akad. Wiss., Munich, 1976, No. 7, for Cartesian coordinate systems.) A coordinate system independent Eulerian formulation for the Lagrangian allowing for equilibria with flow and with built-in conservation laws for mass, magnetic flux, and entropy is developed in this paper which is similar to Newcomb's Lagrangian method of 1962 [Nucl. Fusion, Suppl., Pt. II, 452 (1962)]. For static equilibria nonlinear stability is completely determined by the potential energy. For a potential energy which contains second- and [ital n]th order or some more general contributions only, it is shown in full generality that linearly unstable and marginally stable systems are explosively unstable even for infinitesimal perturbations; linearly absolutely stable systems require finite initial perturbations. For equilibria with Abelian symmetries symmetry breaking initial perturbations are needed, which should be observed in numerical simulations. Nonlinear stability is proved for two simple examples, [ital m]=0 perturbations of a Bennet Z-pinch and [ital z]-independent perturbations of a [theta] pinch. The algebra for treating these cases reduces considerably if symmetries are taken into account from the outset, as suggested by M. N. Rosenbluth (private communication, 1992).

Pfirsch, D. (Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, D-8046 Garching (Germany)); Sudan, R.N. (Laboratory of Plasma Studies, Cornell University, Ithaca, New York 14853 (United States))

1993-07-01

424

Solar Flares: Magnetohydrodynamic Processes  

NASA Astrophysics Data System (ADS)

This paper outlines the current understanding of solar flares, mainly focused on magnetohydrodynamic (MHD) processes responsible for producing a flare. Observations show that flares are one of the most explosive phenomena in the atmosphere of the Sun, releasing a huge amount of energy up to about 10^32 erg on the timescale of hours. Flares involve the heating of plasma, mass ejection, and particle acceleration that generates high-energy particles. The key physical processes for producing a flare are: the emergence of magnetic field from the solar interior to the solar atmosphere (flux emergence), local enhancement of electric current in the corona (formation of a current sheet), and rapid dissipation of electric current (magnetic reconnection) that causes shock heating, mass ejection, and particle acceleration. The evolution toward the onset of a flare is rather quasi-static when free energy is accumulated in the form of coronal electric current (field-aligned current, more precisely), while the dissipation of coronal current proceeds rapidly, producing various dynamic events that affect lower atmospheres such as the chromosphere and photosphere. Flares manifest such rapid dissipation of coronal current, and their theoretical modeling has been developed in accordance with observations, in which numerical simulations proved to be a strong tool reproducing the time-dependent, nonlinear evolution of a flare. We review the models proposed to explain the physical mechanism of flares, giving an comprehensive explanation of the key processes mentioned above. We start with basic properties of flares, then go into the details of energy build-up, release and transport in flares where magnetic reconnection works as the central engine to produce a flare.

Shibata, Kazunari; Magara, Tetsuya

2011-12-01

425

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

426

Investigations of transient phenomena in MHD experimental facilities  

Microsoft Academic Search

Wideband data from experiments with combustion driven MHD power generation is presented. These data were achieved from past MHD research conducted by UTSI on several MHD test trains of variable size and interaction. Measurements of transient and dynamic phenomena related to combustion, plasmadynamics and MHD generator electrical output are discussed. The signal characteristics of these data are qualified and the

B. C. Winkleman; J. T. Lineberry

1991-01-01

427

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

NASA Astrophysics Data System (ADS)

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.

428

Modeling the Earth's Magnetosphere using Magnetohydrodynamics  

NASA Astrophysics Data System (ADS)

This thesis describes work on building numerical models of the Earth's magnetosphere using magnetohydrodynamics (MHD) and other related modeling methods. For many years, models that solve the MHD equations have been the main tool for improving our theoretical understanding of the large-scale dynamics of the Earth's magnetosphere. While the MHD models have been very successful in capturing many large-scale features, they fail to adequately represent the important drift physics in the inner magnetosphere. Consequently, the ring current, which contains most of the particle energy in the inner magnetosphere, is not realistically represented in MHD models. In this thesis, Chapter 2 and 3 will describe in detail our effort to couple the OpenGGCM (Open Geospace General Circulation Model), one of the major MHD models, to the Rice Convection Model (RCM), an inner magnetosphere ring current model, with the goal of including energy dependent drift physics into the MHD model. In Chapter 4, we will describe an initial attempt to use a direct-integration method to calculate Birkeland currents in the MHD code. Another focus of the thesis work, presented in Chapter 5, addresses a longstanding problem on how a geomagnetic substorm can occur within the closed field line region of the tail. We find a scenario of a bubble-blob pair formation in an OpenGGCM simulation just before the expansion phase of the substorm begins and the subsequent separation of the bubble and the blob decreases the normal component of the magnetic field until finally an X-line occurs. Thus the formation of the bubble-blob pair may play an important role in changing the magnetospheric configuration from a stretched field to the X-line formation that is believed to be the major signature of a substorm.

Hu, Bei

429

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

430

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

431

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

432

Residual Energy in Magnetohydrodynamic Turbulence  

NASA Astrophysics Data System (ADS)

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 Er = Ev - Eb , 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 || = 0 with its k ||-spectrum broadening linearly with k bottom, where k || and k bottom are the wavenumbers parallel and perpendicular to the background magnetic field, and the field-perpendicular spectrum of the residual energy has the scaling Er (k bottom)vpropk -1 bottom 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 Alfvénic turbulence and it should be taken into account for the correct interpretation of observational and numerical data.

Wang, Yuxuan; Boldyrev, Stanislav; Perez, Jean Carlos

2011-10-01

433

MHD Program Plan, FY 1992  

SciTech Connect

The current MHD program being implemented is a result of a consensus established in public meetings held by the Department of Energy in 1984. Essential elements of the current program include: (1) develop technical and environmental data for the integrated MHD topping cycle system through POC testing (1,000 hours); (2) develop technical and environmental data for the integrated MHD bottoming cycle sub system through POC testing (4,000 hours); (3) design, construct, and operate a seed regeneration POC facility (SRPF) capable of processing spent seed materials from the MHD bottoming cycle; (4) prepare conceptual designs for a site specific MHD retrofit plant; and (5) continue system studies and supporting research necessary for system testing. The current MHD program continues to be directed toward coal fired power plant applications, both stand-alone and retrofit. Development of a plant should enhance the attractiveness of MHD for applications other than electrical power. MHD may find application in electrical energy intensive industries and in the defense sector.

Not Available

1991-10-01

434

Liquid-metal flows: Magnetohydrodynamics and applications; Proceedings of the Fifth Beersheba International Seminar on Magnetohydrodynamic Flows and Turbulence, University of the Negev, Beersheba, Israel, Mar. 2-6, 1987  

Microsoft Academic Search

The present collection of papers on MHD-related uses of liquid metal flows and their applications discusses topics in laminar MHD flows, MHD power generation, metallurgical MHD applications, and two-phase MHD flows. Attention is given to MHD flows with closed streamlines, nonlinear waves in liquid metals under a transverse magnetic field, liquid-metal MHD conversion of nuclear energy to electricity, the testing

Herman Branover; Michael Mond; Yeshajahu Unger

1988-01-01

435

3D MHD Simulations of Stratified Accretion Disks  

NASA Astrophysics Data System (ADS)

We investigate the growth and nonlinear saturation of a powerful local shear instability in weakly magnetised accretion disks using three dimensional magnetohydrodynamic (MHD) simulations. To achieve a sufficiently high numerical resolution, we use a local approximation for the disk and carry out the simulations on massively parallel supercomputers. Here we investigate the linear growth and nonlinear saturation of the instability in a vertically stratified, intially isothermal disk. A variety of initial field configurations and strengths are considered. The simulations allow a quantitative analysis of the role of bouyancy as a saturation mechanism, and possible dynamo action in the disk. This work is partially supported by NSF grant PHY-9018251 and NASA grants NAGW-1510 and NAGW-2376. Code development is supported by the NASA HPCC Initiative through grant NAG5-2202. Computations were carried out on the CM200 system of the National Center for Supercomputing Applications.

Stone, James M.; Hawley, John F.; Gammie, Charles

1993-12-01

436

Superconducting magnet system for an experimental disk MHD facility  

Microsoft Academic Search

A predesign of a split-pair magnet for a magnetohydrodynamic (MHD) facility for testing a 10-MW open-cycle disk or a 5-MW closed-cycle disk generator is presented. The magnet system consists of a NbTi and a Nb 3Sn section, which provide a magnetic field of 9 T in the active area of the MHD channel. The optimization process, which is based on

H. G. Knoopers; H. H. J. ten Kate; L. J. M. van de Klundert; P. Massee; W. J. M. Balemans

1991-01-01

437

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

438

Modeling the Resistive MHD by the Cese Method  

Microsoft Academic Search

In this paper, the Space–Time Conservation Element and Solution Element (CESE) method is applied to 2.5-dimensional resistive\\u000a magnetohydrodynamics (MHD) equations in Cartesian coordinates, with the purpose of modeling the magnetic reconnection study.\\u000a To show the validity and capacity of its application to MHD reconnection problem, spontaneous fast reconnection and magnetic\\u000a reconnection in multiple heliospheric current sheets are studied, which show

Xueshang Feng; Yanqi Hu; Fengsi Wei

2006-01-01

439

Numerical simulations of Hall MHD small-scale dynamos  

NASA Astrophysics Data System (ADS)

Much of the progress in our understanding of dynamo mechanisms, has been made within the theoretical framework of magnetohydrodynamics (MHD). However, for sufficiently diffuse media, the Hall effect eventually becomes non-negligible. We present results from three dimensional simulations of the Hall-MHD equations subjected to random non-helical forcing. We study the role of the Hall effect in the dynamo efficiency for different values of the Hall parameter, using a pseudospectral code to achieve exponentially fast convergence.

Gómez, Daniel O.; Mininni, Pablo D.; Dmitruk, Pablo

2010-11-01

440

The alternating direction implicit numerical solution of the time-dependent, 3-dimensional resistive single fluid magnetohydrodynamic equations  

Microsoft Academic Search

Resistive magnetohydrodynamics (MHD) is described by a set of eight coupled, nonlinear, three dimensional, time dependent, partial differential equations. A computer code implicit MHD program was developed to solve these equations numerically by the method of finite differences on an Eulerian mesh. In this model, the equations are expressed in orthogonal curvilinear coordinates, making the code applicable to a variety

C. H. Finan III

1980-01-01

441

Alternating-direction implicit numerical solution of the time-dependent, three-dimensional, single fluid, resistive magnetohydrodynamic equations  

Microsoft Academic Search

Resistive magnetohydrodynamics (MHD) is described by a set of eight coupled, nonlinear, three-dimensional, time-dependent, partial differential equations. A computer code, IMP (Implicit MHD Program), has been developed to solve these equations numerically by the method of finite differences on an Eulerian mesh. In this model, the equations are expressed in orthogonal curvilinear coordinates, making the code applicable to a variety

Finan

1980-01-01

442

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

443

Magnetogasdynamic phenomena in pulsed MHD flows. Interim summary report, 1 August 1977-31 October 1978  

Microsoft Academic Search

This report examines some of the detailed structure of magnetogasdynamic flows encountered in pulsed magnetohydrodynamic (MHD) generators. Two illustrations of magnetogasdynamic nonuniformities are considered. The first is for conventional explosive-driven MHD generators. Here we reveal the detailed structure of the deceleration of the conducting slug formed by the compression of plasma between the explosive-driven shock wave and its following contact

S. T. Demetriades; D. M. Markham; C. D. Maxwell; D. A. Oliver; T. F. Swean

1978-01-01

444

MHD Flow Control of Oblique Shock Waves Around Ramps in Low-temperature Supersonic Flows  

Microsoft Academic Search

This article is devoted to experimental study on the control of the oblique shock wave around the ramp in a low-temperature supersonic flow by means of the magnetohydrodynamic(MHD) flow control technique. The purpose of the experiments is to take advantage of MHD interaction to weaken the oblique shock wave strength by changing the boundary flow characteristics around the ramp. Plasma

Su Changbing; Li Yinghong; Cheng Bangqin; Wang Jian; Cao Jun; Li Yiwen

2010-01-01

445

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

446

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

447

Open-closed field line boundary position: A parametric study using an MHD model  

Microsoft Academic Search

In this paper we investigate the effect of changes in the interplanetary magnetic field (IMF), solar wind dynamic pressure, and dipole tilt angle on the position of the ionospheric projection of the open-closed field line boundary (OCB) in a magnetohydrodynamic (MHD) model. We carry out a large number of steady state global MHD simulations in order to parameterize the OCB

K. Kabin; R. Rankin; G. Rostoker; R. Marchand; I. J. Rae; A. J. Ridley; T. I. Gombosi; C. R. Clauer; D. L. DeZeeuw

2004-01-01

448

SPECTRAL METHODS FOR TIME-DEPENDENT STUDIES OF ACCRETION FLOWS. III. THREE-DIMENSIONAL, SELF-GRAVITATING, MAGNETOHYDRODYNAMIC DISKS  

SciTech Connect

Accretion disks are three-dimensional, turbulent, often self-gravitating, magnetohydrodynamic (MHD) flows, which can be modeled with numerical simulations. In this paper, we present a new algorithm that is based on a spectral decomposition method to simulate such flows. Because of the high order of the method, we can solve the induction equation in terms of the magnetic vector potential and, therefore, ensure trivially that the magnetic fields in the numerical solution are divergence free. The spectral method also suffers minimally from numerical dissipation and allows for an easy implementation of models for subgrid physics. Both properties make our method ideal for studying MHD turbulent flows such as those found in accretion disks around compact objects. We verify our algorithm with a series of standard tests and use it to show the development of MHD turbulence in a simulation of an accretion disk. Finally, we study the evolution and saturation of the power spectrum of MHD turbulence driven by the magnetorotational instability.

Chan Chikwan [Institute for Theory and Computation, Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Psaltis, Dimitrios; Oezel, Feryal [Steward Observatory, the University of Arizona, 933 N Cherry Avenue, Tucson, AZ 85721 (United States)

2009-07-20

449

Low Mach number limit for the multi-dimensional full magnetohydrodynamic equations  

NASA Astrophysics Data System (ADS)

The low Mach number limit for the multi-dimensional full magnetohydrodynamic (MHD) equations, in which the effect of thermal conduction is taken into account, is rigorously justified within the framework of classical solutions with small density and temperature variations. Moreover, we show that for a sufficiently small Mach number, the compressible MHD equations admit a smooth solution on the time interval where the smooth solution of the incompressible MHD equations exists. In addition, the low Mach number limit for the ideal MHD equations with small entropy variation is also investigated. The convergence rates are obtained in both cases.

Jiang, Song; Ju, Qiangchang; Li, Fucai

2012-05-01

450

Development Program for MHD Direct Coal-Fired Power Generation Test Facility. Quarterly Technical Progress Report, July-September 1977.  

National Technical Information Service (NTIS)

Tests conducted in the existing MHD facility supported areas critical to the design of components for the new intermediate-size, direct coal-fired MHD development facility. A new combustor design concept was developed and tested. In the coal to oxygen rat...

J. B. Dicks H. P. Markant R. C. Attig

1977-01-01

451

Development Program for MHD Direct Coal-Fired Power Generation Test Facility. Quarterly Technical Progress Report, April--June 1977.  

National Technical Information Service (NTIS)

Tests conducted in the existing MHD facility were concentrated in areas critical to the design of components for the new intermediate-size, direct coal-fired MHD test facility. Tests in the area of slag/seed separation and seed recovery were begun for the...

J. B. Dicks H. P. Markant M. S. Beaton

1977-01-01

452

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

453

Regular shock refraction in planar ideal MHD  

NASA Astrophysics Data System (ADS)

We study the classical problem of planar shock refraction at an oblique density discontinuity, separating two gases at rest, in planar ideal (magneto)hydrodynamics. In the hydrodynamical case, 3 signals arise and the interface becomes Richtmyer-Meshkov unstable due to vorticity deposition on the shocked contact. In the magnetohydrodynamical case, on the other hand, when the normal component of the magnetic field does not vanish, 5 signals will arise. The interface then typically remains stable, since the Rankine-Hugoniot jump conditions in ideal MHD do not allow for vorticity deposition on a contact discontinuity. We present an exact Riemann solver based solution strategy to describe the initial self similar refraction phase. Using grid-adaptive MHD simulations, we show that after reflection from the top wall, the interface remains stable.

Delmont, P.; Keppens, R.

2010-03-01

454

Time-dependent model of particle acceleration in the vicinity of approaching magnetohydrodynamic flows  

NASA Astrophysics Data System (ADS)

Supernova explosions and powerful stellar winds with strong shocks can convert a sizeable part of the kinetic energy release into energetic particles. The starforming regions are argued as a favorable site of energetic particle acceleration and could be efficient sources of nonthermal emission. We present the analytic solution for the time-dependent diffusion-convection equation for the case of two approaching shocks. We also present here time-dependent model of particle acceleration in the vicinity of two closely approaching fast magnetohydrodynamic (MHD) shocks. Such MHD flows are expected to occur in rich young stellar cluster where a supernova is exploding in the vicinity of a strong stellar wind of a nearby massive star. We find that the spectrum of the high energy particles accelerated at the stage of two closely approaching shocks can be harder than that formed at a forward shock of an isolated supernova remnant. The presented method can be applied to model particle acceleration in a variety of systems with colliding MHD flows.

Gladilin, P. E.; Bykov, A. M.; Osipov, S. M.

2013-08-01

455

Corrosion and arc erosion in MHD channels  

SciTech Connect

The objective of this task is to study the corrosion and arc erosion of 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.

Rosa, R.J. (Montana State Univ., Bozeman, MT (United States). Dept. of Mechanical Engineering); Pollina, R.J. (Montana State Univ., Bozeman, MT (United States). Dept. of Mechanical Engineering Avco-Everett Research Lab., Everett, MA (United States))

1991-10-01

456

Thermodynamics of magnetohydrodynamic flows with axial symmetry  

NASA Astrophysics Data System (ADS)

We present strategies based upon optimization principles in the case of the axisymmetric equations of magnetohydrodynamics (MHD). We derive the equilibrium state by using a minimum energy principle under the constraints of the MHD axisymmetric equations. We also propose a numerical algorithm based on a maximum energy dissipation principle to compute in a consistent way the nonlinearly dynamically stable equilibrium states. Then, we develop the statistical mechanics of such flows and recover the same equilibrium states giving a justification of the minimum energy principle. We find that fluctuations obey a Gaussian shape and we make the link between the conservation of the Casimirs on the coarse-grained scale and the process of energy dissipation. We contrast these results with those of two-dimensional hydrodynamical turbulence where the equilibrium state maximizes a H function at fixed energy and circulation and where the fluctuations are nonuniversal.

Leprovost, N.; Dubrulle, B.; Chavanis, P.-H.

2005-03-01

457

Numerical Methods for Radiation Magnetohydrodynamics in Astrophysics  

SciTech Connect

We describe numerical methods for solving the equations of radiation magnetohydrodynamics (MHD) for astrophysical fluid flow. Such methods are essential for the investigation of the time-dependent and multidimensional dynamics of a variety of astrophysical systems, although our particular interest is motivated by problems in star formation. Over the past few years, the authors have been members of two parallel code development efforts, and this review reflects that organization. In particular, we discuss numerical methods for MHD as implemented in the Athena code, and numerical methods for radiation hydrodynamics as implemented in the Orion code. We discuss the challenges introduced by the use of adaptive mesh refinement in both codes, as well as the most promising directions for future developments.

Klein, R I; Stone, J M

2007-11-20

458

Magnetohydrodynamics topping cycle: The Component Development Integration Facility, Butte, Montana  

SciTech Connect

The Component Development and Integration Facility (CDIF) is a highly flexible 50 MW thermal magnetohydrodynamic (MHD) testing facility operated for the US Department of Energy by MSE, Inc. It occupies 50 acres of a 93 acre site located 5 miles south of Butte, Montana. It is a dual purpose facility for development testing of MHD components and determining component and subsystem interactions. This facility description divides the components of the CDIF into three groups on a systematic basis. The first area is designated test train support systems and deals with the primary functions of MHD operations; the second area is designated auxiliary systems and deals with utilities and operational support functions which are secondary to the MHD operations; the third area is designated building and yard facilities and gives dimensional capacity descriptions on the structural elements of the CDIF.

Not Available

1990-04-01

459

Spontaneous chiral symmetry breaking of Hall magnetohydrodynamic turbulence.  

PubMed

Hall magnetohydrodynamics (MHD) is investigated through three-dimensional direct numerical simulations. We show that the Hall effect induces a spontaneous chiral symmetry breaking of the turbulent dynamics. The normalized magnetic polarization is introduced to separate the right- (R) and left-handed (L) fluctuations. A classical k(-7/3) spectrum is found at small scales for R magnetic fluctuations which corresponds to the electron MHD prediction. A spectrum compatible with k(-11/3) is obtained at large-scales for the L magnetic fluctuations; we call this regime the ion MHD. These results are explained heuristically by rewriting the Hall MHD equations in a succinct vortex dynamical form. Applications to solar wind turbulence are discussed. PMID:23215387

Meyrand, Romain; Galtier, Sébastien

2012-11-07

460

Electromagnetic pulse (EMP) interaction with electric power systems. Power Systems Technology Program. Final report  

SciTech Connect

A high altitude nuclear burst, detonated at a height of 50 km or more, causes two types of electromagnetic pulses (EMP) - high altitude EMP (HEMP) and magnetohydrodynamic EMP (MHD-EMP). This high altitude EMP scenario is of principal concern when assessing the effects of EMP on electric power systems, because the total United States can be simultaneously illuminated by HEMP and MHD-EMP can cover a large area of up to several hundred kilometers in diameter. The purpose of this project was first to define typical electrical power system characteristics for EMP analysis, and second, to determine reasonable worst case EMP induced surges on overhead electric power system transmission and distribution lines for reasonable assumptions, using unclassified HEMP and MHD-EMP electric field waveforms.

Zaininger, H.W.

1984-08-01

461

Intensive Mhd-Structures Penetration in the Middle Atmosphere Initiated in the Ionospheric Cusp under Quiet Geomagnetic Conditions.  

National Technical Information Service (NTIS)

In connection with the recently detected quasiperiodical magnetic disturbances in the ionospheric cusp, the penetration of compressional surface magnetohydrodynamic (MHD) waves through the middle atmosphere is modelled numerically. For the COSPAR Internat...

L. N. Mateev P. I. Nenovski P. I. Vellinov

1989-01-01

462

Hypersonic MHD Propulsion System Integration for the Mercury Lightcraft  

NASA Astrophysics Data System (ADS)

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 & 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.; Rosa, R. J.

2004-03-01

463

Magnetohydrodynamic Augmentation of Pulse Detonation Engines  

NASA Astrophysics Data System (ADS)

Pulse detonation engines (PDEs) are the focus of increasing attention due to their potentially superior performance over constant pressure engines. Yet due to its unsteady chamber pressure, the PDE system will either be over- or under-expanded for the majority of the cycle, with energy being used without maximum gain. Magnetohydrodynamic (MHD) augmentation offers the opportunity to extract energy and apply it to a separate stream where the net thrust will be increased. With MHD augmentation, such as in the Pulse Detonation Rocket-Induced MHD Ejector (PDRIME) concept, energy could be extracted from the high speed portion of the system, e.g., through a generator in the nozzle, and then applied directly to another flow or portion of the flow as a body force. The present high resolution numerical simulations explore the flow evolution and potential performance of such propulsion systems. An additional magnetic piston applying energy in the PDE chamber can also act in concert with the PDRIME for separate thrust augmentation. Results show that MHD can indeed influence the flow and pressure fields in a beneficial way in these configurations, with potential performance gains under a variety of flight and operating conditions. There are some challenges associated with achieving these gains, however, suggesting further optimization is required.

Zeineh, Christopher; Cole, Lord; Karagozian, Ann

2010-11-01

464

Magnetohydrodynamics on an unstructured moving grid  

NASA Astrophysics Data System (ADS)

Magnetic fields play an important role in astrophysics on a wide variety of scales, ranging from the Sun and compact objects to galaxies and galaxy clusters. Here we discuss a novel implementation of ideal magnetohydrodynamics (MHD) in the moving-mesh code AREPO which combines many of the advantages of Eulerian and Lagrangian methods in a single computational technique. The employed grid is defined as the Voronoi tessellation of a set of mesh-generating points which can move along with the flow, yielding an automatic adaptivity of the mesh and a substantial reduction of advection errors. Our scheme solves the MHD Riemann problem in the rest frame of the Voronoi interfaces using the HLLD Riemann solver. To satisfy the divergence constraint of the magnetic field in multiple dimensions, the Dedner divergence cleaning method is applied. In a set of standard test problems, we show that the new code produces accurate results and that the divergence of the magnetic field is kept sufficiently small to closely preserve the correct physical solution. We also apply the code to two first application problems, namely supersonic MHD turbulence and the spherical collapse of a magnetized cloud. We verify that the code is able to handle both problems well, demonstrating the applicability of this MHD version of AREPO to a wide range of problems in astrophysics.

Pakmor, Ruediger; Bauer, Andreas; Springel, Volker

2011-12-01

465

Gravitational Radiation from Primordial Helical Inverse Cascade MHD Turbulence  

Microsoft Academic Search

We consider the generation of gravitational waves by primordial helical\\u000ainverse cascade magnetohydrodynamic (MHD) turbulence produced by bubble\\u000acollisions at the electroweak phase transition. We extend the previous study\\u000a\\\\cite{kgr08} by considering both currently discussed models of MHD turbulence.\\u000aFor popular electroweak phase transition parameter values, the generated\\u000agravitational wave spectrum is only weakly dependent on the MHD turbulence\\u000amodel.

Tina Kahniashvili; Leonardo Campanelli; Grigol Gogoberidze; Yurii Maravin; Bharat Ratra

2008-01-01

466

MHD augmented chemical rocket propulsion for space applications  

SciTech Connect

A performance analysis is carried out of a magnetohydrodynamic (MHD) augmented chemical thruster (based on a gaseous hydrogen-oxygen system) for space applications such as orbit transfer. The mathematical model used in the analysis is a one-dimensional flow model using equilibrium chemistry for the combustor, choked nozzle, and MHD channel portions of the system, and chemical nonequilibrium kinetics for the high area-ratio gas dynamic nozzle portion of the system. The performance of the chemical-MHD-augmented thruster is compared with that of a pure electric thruster of the same specific impulse level. 13 refs.

Schulz, R.J.; Chapman, J.N.; Rhodes, R.P. (Tennessee, University, Tullahoma (United States))

1992-07-01

467

Magnetohydrodynamic waves and coronal seismology: an overview of recent results.  

PubMed

Recent observations have revealed that magnetohydrodynamic (MHD) waves and oscillations are ubiquitous in the solar atmosphere, with a wide range of periods. We give a brief review of some aspects of MHD waves and coronal seismology that have recently been the focus of intense debate or are newly emerging. In particular, we focus on four topics: (i) the current controversy surrounding propagating intensity perturbations along coronal loops, (ii) the interpretation of propagating transverse loop oscillations, (iii) the ongoing search for coronal (torsional) Alfvén waves, and (iv) the rapidly developing topic of quasi-periodic pulsations in solar flares. PMID:22665899

De Moortel, Ineke; Nakariakov, Valery M

2012-07-13

468

The space-time CE/SE method for solving one-dimensional special relativistic magnetohydrodynamics equations  

NASA Astrophysics Data System (ADS)

The development of powerful computational tools for simulating phenomena that inhibits the relativistic magnetohydrodynamic (MHD) structure has become one of the core research issues in astrophysics and is one of the compelling fields. The relativistic MHD equations are more complex than the non-relativistic ones due to non-linear relations between conserved and state (primitive) variables. The non-linearity of the systems and the flow near speed of light pose major challenges to the theoretical investigation of the models and to the numerical solution techniques. The current numerical study is related to the implementation of the space-time conservation element and solution element (CE/SE) method for solving one-dimensional special relativistic magnetohydrodynamic (SRMHD) equations. In contrast to the existing upwind finite volume schemes, the Riemann solver and reconstruction procedure are not the building blocks of the suggested method. The method differs from previous techniques because of global and local flux conservation in a space-time domain without resorting to interpolation or extrapolation. For validation, the numerical results of the method are compared with the second order central and kinetic flux-vector splitting schemes. The one-dimensional computations of this paper verify the method's efficiency, robustness and accuracy which are the key parameters in the context of astrophysical scenario.

Qamar, Shamsul; Ahmed, Sidrah

2013-04-01

469

Wall functions for numerical modeling of laminar MHD flows  

Microsoft Academic Search

A general wall function treatment is presented for the numerical modeling of laminar magnetohydrodynamic (MHD) flows. The wall function expressions are derived analytically from the steady-state momentum and electric potential equations, making use only of local variables of the numerical solution. No assumptions are made regarding the orientation of the magnetic field relative to the wall, nor of the magnitude

Ola Widlund

2003-01-01

470

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

471

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

472

Numerical investigation of unsteady real gas flowfields with MHD effects  

Microsoft Academic Search

The design of ground based test facilities to simulate high temperature flight environments has received much attention in recent years. This dissertation deals with the numerical simulation of such facilities in order to assist their design and estimate their importance in modern aerodynamic research. The central problem addressed here is the simulation of a Magnetohydrodynamics (MHD) based accelerator which can

Ramakanth Munipalli

1998-01-01

473

MHD waves and heating of the solar corona  

Microsoft Academic Search

Magnetohydrodynamic (MHD) waves play an important role in the solar atmosphere both directly (or intrinsically), e.g. as the main drivers or causes of atmospheric phenomena, and indirectly, e.g. as diagnostic tools for investigating the inner structure and physical properties of the magnetic configurations observed on the Sun. As a matter of fact, this research domain is actually a 'hot topic'

Stefan Poedts

2002-01-01

474

Simulation of Charged Particle Diffusion in MHD plasmas  

Microsoft Academic Search

Magnetohydrodynamical simulations of turbulent plasmas have been performed to study the transport of energetic test particles. Several parameters of the underlying MHD simulation have been varied to gain insight into the main processes governing transport. Here also the distinct effects of wave-particle resonance and field line wandering shall be studied.

F. Spanier; M. Wisniewski

2011-01-01

475

Experimental determination of the MHD-EMP effects on power distribution transformers  

Microsoft Academic Search

It is a well-established fact that geomagnetic storms influence electrical power transmission and distribution systems. Previous cases of such storms in the northern latitudes have resulted in occasional power disruptions, and in some cases, damage to transformers. These effects are caused by a time variation of the earth's magnetic field creating an induced electric field along the surface of the

B. W. McConnell; Paul R. Barnes; Frederick M. Tesche

1991-01-01

476

MHD coal-fired flow facility. Quarterly technical progress report, January-March 1979  

Microsoft Academic Search

The overall objective is to advance the technology of direct coal-fired MHD components and systems required for MHD power systems operating under engineering simulation of central power station power conditions. The specific objectives of the UTSI R and D MHD Facility and the MHD Coal-Fired Flow Facility are to resolve experimentally and analytically the key technical problems which have been

J. B. Dicks; H. P. Markant; L. W. Crawford

1979-01-01

477