Stirling space power demonstrator engine test/analytical comparison

Abstract

The U.S. Government is evaluating power requirements for future space applications. As power requirements increase, solar or nuclear dynamic systems become increasingly attractive. Free Piston Stirling Engines (FPSE) have the potential to provide high reliability, long life, and efficient operation at reasonable hot-side temperatures. Therefore, they are excellent candidates for the dynamic power conversion module of a space-based, power-generating system. FPSEs are at an early stage of technological development; however, they are recognized as a potential backup and/or growth version within the SP-100 program, which is developing a space power system utilizing a liquid metal nuclear reactor as a heat source and thermoelectric cells for power generation. As part of the SP-100 technology assessment program and the continuing NASA advanced technology development program, Mechanical Technology Incorporated (MTI) was awarded a contract (managed by NASA/Lewis Research Center) to design, fabricate, test, and demonstrate a 25-kW e Space Power Demonstrator Engine (SPDE). Full pressure testing of the SPDE was initiated in November 1985. Initial test results indicated that the SPDE was significantly down in power compared to analytical predictions at the design pressure. The first three months of 1986 were spent performing an extensive diagnostic test series to identify and correct the cause of the power discrepancy. The diagnostic test phase has been completed successfully with a resolution of the SPDE power discrepancy. This paper briefly reviews the SPDE design and presents the experimental results generated to date compared with analytical predictions.