SBIR-STTR Award

A novel chemical fuel fired combustor is proposed for use as a low-cost heat source to simulate gas-cooled, nuclear reactors operating at temperatures above 2000°K. These reactors can operate very efficiently with magnetohydrodynamic (MHD) electric power generators, using inert or noble gases as the generator working fluid. The chemical fuel-fired combustor allows the heating of the MHD generator working fluid to conditions that can sharply increase the MHD generator performance to levels far beyond the best results reported to date in any MHD generator operating for periods of several seconds or more. It is also proposed to determine the feasibility of applying a novel high-efficiency condensing gas power cycle to a space-based nuclear-MHD power system or a space-based MHD system using the novel combustor. In Phase I of the project, the performance requirements for the combustor will be determined from nuclear-MHD cycle analyses and MHD generator analyses. The optimum performance conditions will be used in a conceptual design of a chemical fuel, combustor-MHD system. The output of the study will be the conceptual design of this combustor-MHD system at a scale suitable for low-cost experimental verification in subsequent project phases. Validation of the proposed combustor concept would represent a major advance in high-power generation technology, for both pulsed and continuous applications, using chemical or nuclear heat sources.Anticipated Results/Potential Commercial Applications as described by the awardee:Potential applications of this combustor are for terrestrial simulation of nuclear and non-nuclear space power systems, with or without the MHD generator and as a compact, transportable, high-temperature heat source for MHD power systems operating at one to thousands of megawatt output, for periods of several seconds to a fraction of an hour. Examples of the latter application are high power for use in remote geological testing or for high field pulsed magnets. Other potential applications of the combustor are as a heat source for specialized industrial processes or for aerodynamic wind tunnel testing.

The objective of this project is to validate experimentally one of the two most critical technical feasibility issues related to a novel very high-performance, non-equilibrium MHD generator using a chemical fuel as a direct heat source for the MHD generator working fluid. The novel feature of this concept, which will be validated in Phase 11, is to use the very high temperatures attainable with chemical fuels to directly heat a low atomic weight gas to conditions at which non-equihbrium MHD power output is obtained at levels considerably higher than has been achieved to date in steady state MHD generators. Enthalpy extractions approaching 50% are projected. To accomplish this validation at modest cost, a series of short timeduration experiments will be performed using a novel chemical fuel formulation especially prepared for the test effort. The short-duration tests will allow operation of both the MHD channel and the self-excited MHD magnet in the heat sink mode which simplifies the construction techniques. The project consists of 4 tasks. In task 1, the heat source and generator performance will be defined. This includes selection of the preferred fueloxidizer and matching the heat source to the generator output. In task 2, the chemical fuel combustor will be fabricated and checked experimentally. Also, the MHD channel and magnet will be designed and fabricated. In task 3, short-duration tests will be performed to verify that this concept can convert about 20% of the stagnation enthalpy in a channel that has several MW of thermal input and whose dimensions are a small fraction of present chemicaUy6fired, equilibrium MHD generators. In task 4, the initial work in Phase I on the use of this system in a space-based power application will be extended to select and optimize the preferred space power cycle system configuration.Anticipated Results Potential Commercial Apphcations as described by the awardee:Potential applications of the MHD concept are the following- a compact, transportable, high power-density electric system operating at 1 to 1000 megawatts of output for periods of a fraction of one second to a fraction of an hour and applicable to land, sea, air, and space-based enviromnenta Special applications are as follows: the terrestrial simulation of nuclear and nonnuclear space power systems, portable self-contained power supply for remote geological testing, and pulsed power supply for large (100 MWe) fusion test facilities.