ANALYSIS OF THE MAGNETOHYDRODYNAMIC FLOW OF A FISSIONING GAS IN A DISK MHD GENERATOR By GERARD EDWARD WELCH A DISSERTATION PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS OF THE DEGREE OF DOCTOR OF PHILOSOPHY UNIVERSITY OF FLORIDA 1992 UNIVERSITYOFFLOHIDALIBRARIES iiiiiili 31262085524535 Copyright 1992 by Gerard E. Welch "Myeyes are ever toward the Lord, for he will free my feet from the snare." (Psalm 25:15) To myparents, in the name ofourLordJesusChrist. ACKNOWLEDGEMENTS The author wishes to extend his sincere appreciation and thanks to the members ofhis supervisory committee, Dr. Edward T. Dugan, Dr. William E. Lear, Jr.,Dr. William G. Vemetson, Dr. Alan M. Jacobs, Dr. Calvin C. Oliver, and Dr. Robert J. Hanrahan, for their assistance and direction throughout the course ofthis work. The author considers it a privilege to have worked under these outstanding academicians. Special thanks isextended to Dr. Dugan for the hours devoted to reviewing this dissertation, and for his guidance, patience, example, and friendly support over the many years ofthe author's graduate career. The author thanks Dr. Lear for the many enjoyable hours ofdiscussion on MHD and gas dynamics. Thanks is also extended to Dr. Oliver for his detailed insights into all facets ofthermal fluid flow,and for hours ofenjoyable and educational conversation. The author willalways be thankful for the support and constant encouragement provided by Dr. Vernetson throughout his graduate career. Thanks isalso extended to Dr. T. I-P. Shih ofCarnegie-Mellon University for his time spent in answering detailed questions on computational fluid mechanics, and to Dr. J.G. Appelbaum for the interesting discussions and help on the plasma physics modeling. Support for the author's graduate work has been provided in part by the University ofFlorida. The early phase ofthis dissertation work was supported by the Air force Wright Aeronautical Laboratories for work performed within the Innovative Nuclear Space Power Institute ofthe University ofFlorida. The author's masters work was supported byInstitute ofNuclear Power Operations. All this support isgreatly appreciated. The author thanks his friends and family in Gainesville for their moral support throughout this work. A special thanks isextended Jean Roach for her true friendship through some ofthe roughest periods ofthe author's graduate career and for the many prayers made on the author's behalf by her, and the members ofher intercessory prayer group. Finally, the author thanks his parents, Gerard J. Welch and Mary G. Welch, for their patience and love, for the hope they communicated to the author during these past years, for their many sacrifices in devoting time and financial support during the author's graduate career, and especially for their faithful presence and prayers to the Lord who has sustained the author. 1 TABLE OF CONTENTS Eage ACKNOWLEDGMENTS iv LIST OF TABLES viii LIST OF FIGURES x ABSTRACT xviii CHAPTERS INTRODUCTION 1 1 LO Overview 1 1.1 Outflow Disk MHD Generator Power Generation 3 1.2 Background 13 1.3 Problem Statement 17 1.4 Organization ofDissertation 18 2 THEORETICAL MODELING 19 2.0 Introduction 19 2. Overview ofAssumptions 19 2.2 Fluid Mechanics 26 2.3 Electromagnetics 68 2.4 Plasma Physics Modeling and Transport Properties .... 83 2.5 Overall MHD Solution 96 3 ANALYSIS 98 3.0 Introduction 98 3.1 Solution Method Modifications for MHD Calculations .. 99 3.2 Duct Geometry Selection 127 33..34 CUonmipfaorrimsoPnlsasmwiathPrQoupaesrit-yOnMe-HDDimeSnosliuotnioanls Flow Solver . 114544 3.5 Nonuniform Plasma Transport Properties 180 1 CHAPTERS Bags 3 ANALYSIS (cont.) 3.6 Nonuniform Fission-Model Plasma Property MHD Solutions 202 3.7 Comparison ofTwo-Dimensional and Quasi-One- Dimensional Predictions for Reference Equilibrium/ Fission-Model Generator 242 4 SUMMARY, CONCLUSIONS, AND RECOMMENDATIONS 253 4. Summary ofResults 253 4.2 Conclusions 262 4.3 Recommendations for Future Study 265 APPENDICES A QUASI-ONE-DIMENSIONAL DISK MHD FLOW SOLVER 271 B GRID GENERATION 279 C SHOCK CAPTURING 292 LIST OF REFERENCES 300 BIOGRAPHICAL SKETCH 307 LIST OF TABLES Table Cage LI Disk MHD Generator Current Density Component 11 2.1 Governing Equations ofMagnetohydrodynamics 20 2.2 Governing Equations ofMagnetohydrodynamics with Fission Density Terms in Cylindrical Coordinates with Tangential- Symmetry 30 2.3 Transformed Governing Equations ofMHD with Thin-Layer Approximation in Boundary-Fitted Curvilinear Coordinate System (I.tj) 35 2.4 Pure UF4 and He Gas Properties and UF4-(94%)He Working Fluid Mixture Properties 44 2.5 Explicit Method ofMacCormack with Generalized Finite- Differencing Sequence 66 2.6 Transformed MHD Electromagnetics Equations in Boundary- Fitted Curvilinear Coordinate System (1,77) 73 2.7 Constants ofPlasma PhysicsTransport Property Models 92 3.1 Uniform Plasma Property MHD Generator Parameters 156 3.2 Fluid Property Data for a UF4-(85%)He Working Fluid Mixture for Example Fissioning Plasma Transport Property Calculations .... 186 3.3 Wall-to-Free Stream Plasma Property Ratios for Hot and Cold Generator Walls with Example Generator Free Stream Flow Conditions 199 3.4 Working Fluid Properties for Equilibrium Electron Temperature/ Fissioning Plasma (Sff > SjahJ MHD Generator Calculations 203 Table page 3.5 MHD Generator Inlet Conditions and Specified Global Parameters for Nonuniform Fission-Model Plasma Property MHD Generator Calculations 206 3.6 Comparison ofTwo-Dimensional MHD Solver and Quasi-One- Dimensional Euler Solver Predictions for Reference Fissioning Plasma Generator 245