Materials engineering and development for coal fired MHD power generators

This paper attempts to describe the unique stresses imposed on MHD generator materials. This is done by reviewing experimental test histories of two generator designs represent-ing extremes in operating conditions and materials selection. Related experimental work, bearing on the importance of coal-ash slag properties to design functions, is also re-viewed. This latter is particularly critical to U.S. MHD development goals. The range of engineering conditions and materials attending the tests described in this review sug-gests a breadth of design choice which is probably less real than apparent. Engineering development, currently in progress and planned, is directed towards quantitative deter-mination of specific design and material influences on generator performance and dura-bility. Material requirements are closely interrelated with thermal, electrical, and ge-ometric design conditions, as this review will show. Finally, MHD test experience sum-marized here affirms the necessity for close engineering design and test discipline in the development of materials for power machinery applications. This paper is based on a presentation made at a symposium on “Materials Requirements for Unconventional Energy Systems” held at the Niagara Falls meeting of The Metallurgical Society of AIME, September 22, 1976, under the sponsorship of Non-Ferrous Metals and Ferrous Metals Committees.