A Microfabricated Segmented-Involute-Foil Regenerator for Enhancing Reliability and Performance of Stirling Engines: Phase III Final Report for the Radioisotope Power Conversion Technology NRA Contract NAS3-03124

1 1.0 Introduction 2 2.0 Nomenclature 4 2.1 Abbreviations 4 3.0 Regenerator Final Design (Summarized by Gedeon Associates) 5 3.1 Detailed Specifications 5 3.2 Jet Diffuser Design 6 3.3 Thermal Expansion and Assembly Issues 7 3.4 Jet Boundary Conditions 7 4.0 Analysis Tools and CFD Results (Cleveland State University) 8 4.1 CFD Geometry 8 4.2 CFD Results 8 5.0 Regenerator Fabrication (International Mezzo Technologies) 11 5.1 LiGA Process Overview 11 5.2 Manufacturing Process for Stirling Regenerator 12 5.3 Stirling Engine Regenerator Results 15 6.0 FTB Test Results and Analysis (Gedeon Associates and Sunpower) 15 6.1 Regenerator Inspection and Installation 15 6.1.1 Outer Diameter Measurements 16 6.1.2 Overall length 17 6.1.3 Disk Thickness Variation 17 6.1.4 Optical Comparator Methodology 18 6.2 Test Results Versus Sage Predictions 18 6.2.1 Correcting for Nickel Regenerator Conduction 20 6.2.2 Regenerator Flow Friction and Enthalpy Loss Trades 20 6.2.3 Estimated Alternator Efficiency 21 6.2.4 Net Heat Input 21 7.0 Summary 22 8.0 Phase III Conclusions and Recommendations for Future Work 24 Appendix A—Estimated Alternator Efficiency (Gedeon Associates) 27 References 28