This report was prepared at the request of the Tennessee Valley Authority (TVA) to clarify the development status of the pressurized fluidized bed combustor (PFBC) and to place in perspective the problems which are yet to be solved before commercialization of the concept is practical. The report is viewed as preliminary to a more complete and comprehensive work to be carried out during FY 1979. An evaluation of the PFBC concept cites potential advantages over atmospheric pressure fluidized bed combustors (AFBC) in the areas of combustion efficiency, sulfur retention, furnace design, power plant efficiency, and others. The key disadvantage of unproven hot gas cleanup and associated gas turbine technology is discussed in considerable detail. A survey of existing and developing PFBC experimental facilities is presented plus some results from the experimental programs. Recent design studies for full-sized PFBC power plants are reviewed with emphasis on key design parameters. Results for similar AFBC design studies are presented in contrast. The general conclusion drawn from this preliminary survey is that the potential advantages of the PRBC used in conjunction with a high-temperature (850/sup 0/C (1560/sup 0/F)) gas turbine will be difficult to realize due primarily to the formidable task of developing adequate …

Test procedures are formulated to ensure that the alternator stator, P/N 719134, satisfies the requirements set forth within the KIPS Technology Verification Plan.

The solar heating and hot water system installed in existing buildings at the Cherry Hill Inn in Cherry Hill, New Jersey is described in detail. The system went into operation November 8, 1978 and is expected to furnish 31.5% of the overall heating load and 29.8% of the hot water load. The collectors are General Electric Company liquid evacuated tube type. The storage system is an above ground insulated steel water tank with a capacity of 7,500 gallons.

A new two-phase turbine was designed and built for testing in the laboratory, using a low quality steam-water mixture as a working fluid. The measured performance compares well with performance predictions of a numerical model of the expander. Details of the selection of the type of expander are given. The design of an experimental expander for use in a clean two-phase flow laboratory experiment and the development of a numerical model for performance analysis and extrapolations are described. Experiments including static cascade performance with two-phase fluid, disk friction and windage measurements, and two-phase performance measurements of the experimental expander are reported. Comparisons of the numerical model and experimental results, and the prediction of the performance of an advanced design, indicating how performance improvements can be achieved, are also included. An engine efficiency of 23 percent for a single-nozzle test was measured. Full admission performance, based upon the numerical model and achievable nozzle thrust coefficients indicate that an engine efficiency of between 38 and 48 percent can be realized with present technology. If maximum liquid removal loss is assumed, this performance range is predicted to be 38 to 41 percent. Droplet size reduction and the development and implementation of enhanced two-phase …

Research was conducted to improve on presently used techniques for mapping soundspeed variations in the earth by monitoring the return from seismic probes. For small variations in the propagation speed, a linear integral equation was derived for that soundspeed variation. The integral equation is sufficiently general to characterize the placement of sources and receivers. The integral equation was solved in closed form for most of the source-receiver configurations of practical interest. The problem of dealing with the imperfect and incomplete data obtained in the real world was also confronted. The realistically constrained solution was implemented on the computer for a source-receiver configuration commonly used in seismic profiling. This latter project has dominated much of the research effort over the recent contract period.

A new, axial-flow impulse turbine was tested at LLL as part of the geothermal energy development program. Engine efficiency of this single-stage, two-phase expander was measured at 23% during a single-nozzle test. Performance predictions of a numerical model agreed with these results. Full-admission performance (based on the numerical-model and attainable nozzle thrust coefficients) indicates that engine efficiency can reach between 38 and 40% with present technology. Improved techniques for analyzing two-phase flow and further reduction of droplet sizes should provide 70% engine efficiency.

In order to qualify Milliwatt Generator heat sources for an extended design life, multi-axial mechanical tests were performed on the strength member components. The results of these tests indicated that failure occurred predominantly in the middle of the weld ramp-down (down-slope) zone. Examination of the failure zone by standard metallographic techniques failed to indicate the cause of failure. A modified technique utilizing chemical etching, scanning electron microscopy, and energy dispersive x-ray analysis was employed and dramatically indicated the true cause of failure, viz., inclusions in the parent material which were precipitated along the welds. As a result of the initial investigation, weld parameters for the heat sources were altered and preliminary tests on sample welds suggested that pulse-arc welding eliminate this type of failure.

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This report addresses the research and ecology semiannual progress report from July through December 1972.

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