| Nonlinear Loss Mechanisms in Advanced Magnetohydrodynamic Generators. (2002) | |||||||||
Abstract | |||||||||
| Development of improved computer codes for solving the MHD problem has led to improved techniques for inverting the large matrixes that appear in the formulation and application of STD Research Corporation's direct solution of the electrical part of the MHD problem. Application of the STD Research MHD-generator-simulation computer codes to real MHD channels has verified the validity and accuracy of these codes by direct comparison with large-scale experiments. The influence of wall roughness on MHD channel performance has been studied theoretically and it has been found that roughness effects are calculable and in good agreement with experiments. A new phenomenon peculiar to MHD flows, electromagnetic roughness, has been discovered but its investigation was limited to qualitative predictions. The influence of electrode coatings, electron temperature elevation, thermochemistry and transport property changes in the boundary layer was investigated and it was concluded that most losses in MHD generators originate in the boundary layer and electrode voltage drops are calculable with high accuracy. Methods for significantly improving the performance and longevity of MHD generators by boundary layer and surface coating control were investigated theoretically and small-scale experiments for verifying these results are recommended. | |||||||||
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