Gas core nuclear rocket with fuel separation by MHD driven rotation
Operating characteristics and performance predictions for gas-core nuclear rocket with fuel separation by MHD-driven rotation
Love, W. L.↗
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Gas core reactors for MHD power systems
Gas core reactors and MHD generator to solve problems of growing demand for electric power without thermal pollution
Shelton, S. V.↗
MHD boundary layers with non-equilibrium ionization and finite rates
MHD boundary layers with nonequilibrium ionization and recombination at finite rates
Mcassey, E., Jr.↗
The effect of Alfven waves on MHD fast shocks
Alfven waves effect on MHD fast shock from numerical solution of extended Rankine-Hugoniot equations
Belcher, J. W.↗
The potential of nuclear MHD electric power systems
Turbo-MHD cycle technology of nuclear electric power systems with high temperature reactor for space and terrestrial applications
Nichols, L. D.↗
Dispersive waves in a seeded MHD generator.
The equations giving the response of a slightly ionized plasma with monatomic components to sinusoidal perturbations have been formulated. Included in the model equations were the electron Hall effect, electron thermal diffusion, radiation, and electron-atom rate processes. Plasma conditions were limited to those where viscous effects, the induced magnetic field, ion slip, and atom-atom inelastic processes can be neglected. Presented are results of numerical calculations for MHD generators with a working fluid of potassium seeded argon.
Harstad, K. G.↗
MHD Generator Performance Limitations
The electrical properties of the gas are the primary limiting factor to MHD generator performance; the most relevant electrical properties are the conductivity and the Hall parameter. The maximum allowable pressure at several given levels of power extration vs. temperature is represented graphically.
Rosa, R. J.↗
NaK-nitrogen liquid metal MHD converter tests at 30 kW.
Description of the tests performed and test results obtained in an experiment where a NaK-nitrogen liquid metal MHD converter was operated over a range of nozzle inlet pressures of 100 to 165 N per sq cm, NaK flow rates of 46 to 72 kg/sec, and nitrogen flow rates of 3.4 to 3.8 kg/sec. The test results indicate: (1) smooth and stable operation, (2) absence of unexpected electrical or flow losses, and (3) possibility of operation with the expected full power output of 30 kW.
Cerini, D. J.↗
The ratio of specific heats for postshock plasmas of a detached bow shock - An MHD model
The empirical relationship between the standoff distance of a detached bow shock (generated by the flow of a supersonic gas past an impenetrable obstacle), the size of the obstacle, the Mach number of the gas, and the ratio of specific heats has been generalized to include the magnetic field. The value of the ratio of specific heats (gamma-prime) in the postshock plasma has been calculated in terms of the preshock Alfvenic and sonic Mach numbers and orientation of the magnetic field. The empirical relationship is further generalized by taking into consideration the normal momentum and energy flux due to waves and/or turbulence and/or heat flow in association with high Mach number shocks. The computed value of gamma prime is substantially modified in comparison with that given by the MHD or the gas dynamic model. For this generalized model the computed gamma prime can be considered to be a more precise thermodynamic quantity, since the macroscopic parameters of the plasma have been separated out. Application of this empirical relationship to the earth's bow shock has been given.
Chao, J. K.↗
Closed cycle MHD power generation experiments using a helium-cesium working fluid in the NASA Lewis Facility
A MHD channel, which was previously operated for over 500 hours of thermal operation, ten thermal cycles, and 200 cesium injection tests, was removed from the facility and redesigned. The cross sectional dimensions of the channel were reduced to 5 by 16.5 cm to allow operation over a variety of conditions. The redesigned channel has been operated for well over 300 hours, 10 thermal cycles, and 150 cesium injection tests with no problems. Experiments have been run at temperatures of 1900-2100 K and Mach numbers from 0.3 to 0.55 in argon and 0.2 in helium. The best results to date have been obtained in the helium tests. Power outputs of 2.2 kw for tests with 28 electrodes and 2.1 kw for tests with 17 electrodes were realized. Power densities of 0.6 MW/cu m and Hall fields of about 1,100 V/m were obtained in the tests with 17 electrodes.
Sovie, R. J.↗
Results and progress on the NASA Lewis H2-O2 MHD program
It was found that flame sprayed ceramic coatings on combustion chamber and nozzle walls permit operation with hot walls, thereby eliminating possible problems associated with seed condensation. However, under the conditions of experiment the net heat transfer was unexpectedly increased over that of cold copper walls. Pressure disturbances associated with oblique pressure waves were measured in a MHD channel. These disturbances are due to a rocket-type nozzle which was designed to achieve low weight rather than perfectly parallel flow at the exit. A new nozzle with parallel flow at the exit was designed. Electrical conductivity measurements agreed well with theory except at low combustion pressures and/or high ratios of seed/oxygen mass flows (seed was injected into oxygen flow line). The discrepancy is believed to be the result of poor atomization of the seed at high ratios of seed/oxygen mass flows which results in droplet sizes which do not completely vaporize the combustor.
Smith, J. M.↗
Energy Conversion Alternatives Study (ECAS), Westinghouse phase 1. Volume 8: Open-cycle MHD
Electric power plant costs and efficiencies are presented for three basic open-cycle MHD systems: (1) direct coal fired system, (2) a system with a separately fired air heater, and (3) a system burning low-Btu gas from an integrated gasifier. Power plant designs were developed corresponding to the basic cases with variation of major parameters for which major system components were sized and costed. Flow diagrams describing each design are presented. A discussion of the limitations of each design is made within the framework of the assumptions made.
Hoover, D. Q.↗
Acceleration of charged particles in oblique MHD shocks
The motion of high energy charged particles in ideal oblique MHD shocks has been studied extensively. The orbits of charged particles can be solved exactly from Lorentz force equation. It is found that a charged particle may cross the shock front many times before it leaves the shock and it is energized during crossings. The most energetic particles are those with initial pitch and phase near the boundary between crossing and reflected particles. The reflected particles cross the shock about twice as many times as the passing particles do. The energy gain increases for larger values of shock strength and speed. If reflection occurs, the energy gain is larger for smaller angles between the field and shock surface. The introduction of scattering results in a few more higher energy particles.
Chen, G.↗
Closed cycle MHD power generation experiments using a helium-cesium working fluid in the NASA Lewis Facility
The MHD channel in the NASA Lewis Research Center was redesigned and used in closed cycle power generation experiments with a helium-cesium working fluid. The cross sectional dimensions of the channel were reduced to 5 by 16.5 cm to allow operation over a variety of conditions. Experiments have been run at temperatures of 1900-2100 K and Mach numbers from 0.3 to 0.55 in argon and 0.2 in helium. Improvements in Hall voltage isolation and seed vaporization techniques have resulted in significant improvements in performance. Typical values obtained with helium are Faraday open circuit voltage 141 V (92% of uBh) at a magnetic field strength of 1.7 T, power outputs of 2.2 kw for tests with 28 electrodes and 2.1 kw for tests with 17 electrodes. Power densities of 0.6 MW/cu m and Hall fields of about 1100 V/m were obtained in the tests with 17 electrodes, representing a factor of 18 improvement over previously reported results. The V-I curves and current distribution data indicate that while near ideal equilibrium performance is obtained under some conditions, no nonequilibrium power has been generated to date.
Sovie, R. J.↗
Results and progress on the NASA Lewis H2-O2 MHD program
A rocket test facility at the NASA Lewis Research Center has been used to develop interelectrode insulating materials, measure heat losses, and determine the fluid dynamic and electrical properties of MHD ducts and the cesium-seeded H2-O2 working fluid. Test results show that flame sprayed ceramic coatings on combustion chamber and nozzle walls permit operation with hot walls, eliminating problems associated with seed condensation; however, the net heat transfer was unexpectedly increased over that of cold copper walls. Pressure disturbances associated with oblique pressure waves were measured in a rocket nozzle designed to achieve low weight rather than perfectly parallel flow at the exit. Electrical conductivity measurements were in good agreement with theory except at low combustion pressures and/or high seed/oxygen mass flow ratios. The discrepancy is thought to result from poor atomization of the seed, producing droplets which do not completely vaporize during their residence time.
Smith, J. M.↗
Results of closed cycle MHD power generation test with a helium-cesium working fluid
The cross sectional dimensions of the MHD channel in the NASA Lewis closed loop facility were reduced to 3.8 x 11.4 cm. Tests were run in this channel using a helium-cesium working fluid at stagnation pressures of 160,000 n/M2, stagnation temperatures of 2000-2060 K and an entrance Mach number of 0.36. In these tests Faraday open circuit voltages of 200 V were measured which correspond to a Faraday field of 1750 V/M. Power generation tests were run for different groups of electrode configurations and channel lengths. Hall fields up to 1450 V/M were generated. Power extraction per electrode of 183 W and power densities of 1.7 MW/M3 were obtained. A total power output of 2 kW was generated for tests with 14 electrodes. The power densities obtained in this channel represent a factor of 3 improvement over those previously reported for the M = 0.2 channel.
Sovie, R. J.↗
Spectroscopic determination of electrical conductivity in an MHD duct from absolute intensity measurements
Measurements of the electrical conductivity in the NASA Lewis cesium seeded, H2-O2 MHD duct have been previously reported. In order to corroborate the above measurements and to analyze the possibility of nonuniform seed injection as a cause of the deviations, a spectroscopic investigation of the plasma conductivity has been undertaken. Transverse profiles of the absolute integrated intensity were measured from the optically thin lines of CSI-.5664 microns and .5636 microns. Radial profiles of emission coefficient were obtained from the measured transverse profiles of intensity by Abel inversion. Radial profiles of electrical conductivity were then obtained under two different assumptions. In the first, the Cs seed fraction is assumed uniform and equal to the measured flow rate at the time when the temperature and conductivity were obtained. In the second method, the local temperature and pressure are taken to be those given by a one-dimensional channel calculation including heat transfer and friction. In this case profiles of conductivity and seed fractions are obtained. The results of the two methods are compared to the previously measured conductivity.
Wang, S. Y.↗
Results of closed cycle MHD power generation tests with a helium-cesium working fluid
The cross-sectional dimensions of the MHD channel in the NASA Lewis closed loop facility have been reduced to 3.8 x 11.4 cm. Tests were run in this channel using a helium-cesium working fluid at stagnation pressures of 1.6 x 10 to the 5th N/sq m, stagnation temperatures of 2000-2060 K and an entrance Mach number of 0.36. In these tests Faraday open circuit voltages of 200 V were measured which correspond to a Faraday field of 1750 V/m. Power generation tests were run for different groups of electrode configurations and channel lengths. Hall fields up to 1450 V/m were generated. Power extraction per electrode of 183 W and power densities of 1.7 MW/cu m have been obtained. A total power output of 2 kW was generated for tests with 14 electrodes. The power densities obtained in this channel represent a factor of 3 improvement over those reported for the m = 0.2 channel at the last EAM Symposium.
Sovie, R. J.↗