Abstract! This presentation discusses the current state-of-technology and some of the more-pressing research needs and challenges associated with the possible use of high-temperature materials in future high-energy space power systems. Particularly, emphasis is on the need to improve and quantify the fundamental ATTACHMENT : understanding of the effects of the following: (1) fast-neutron radiation on the properties and behavior of nuclear reactor fuels and claddings; and (2) long-term, high-temperature, space (vacuum) exposure on the properties of refractory metals considered for use as structural materials in various power conversion systems. The data presented were abstracted from published papers prepared by numerous authors from several different organizations. Title: A survey of recent advances in and future prospects for thermionic energy conversi on Source: Proceedings of the AFOSR Special Conference of Prime-Power for High Energy Space Systems, Norfolk, Virginia, USA, Feb. 22-25, 1982. (Paper No. IX-3) Authors: Lawless, John; <Carnegie-Mel1 on University? Date: 02-22-82 Classification: u Keywords: space energy conversion, alternative systems Abstract: Some powerful advances in the fundamental understanding of Thermionic Conversion have occurred recently. These include numerical computer simulations and simple analytical models. As a consequence of these advances, many new ideas are being developed with the potential for major improvements in ATTACHMENT : thermionic converter performance. In particular, structured electrodes and oscillation effects now show strong possibilities for important improvements. Further, modeling techniques now exist to consider pore converters and third electrode converters in detail whereas past studies have been mainly empirical. In summary, greatly superior performance can be expected from future thermionic converters. Title: The liquid droplet radiator. Source: Proceedings of the AFOSR Special Conference on Prime-Power for High Energy Space Systems, Norfolk, Virginia, USA, Feb. 22-25, 1982. (Paper No. X-2) Authors: Mattick, A. T. ; Hertzberg, A.; <University of Washington, Seattle, WA> and Taussig, R.; <Mathematical Sciences Northwest, Inc., Bellevue, WA> Date: 02-22-82 Classification: u Keywords: thermal control, space energy conversion Abstract: A new type of radiator will be discussed which uses a recirculating stream of liquid droplets as a radiating element in place of the solid surfaces used in conventional tube and fin radiators for space. By virtue of the large surface to volume ratio of small droplets the liquid droplet radiator (LDR) has ATTACHMENT : the potential of being many times lighter than the lightest solid surface radiators yet developed (heat pipes). In addition the LDR may be much more simply and economically deployed since the radiating element is transported as a liquid. Preliminary studies of the physics and engineering of the LDR have not revealed any exceptional obstacles to development of a practical LDR based on existing technology. Generation of droplets (100 micrometers diameter) may utilize the methods developed for ink-jet printing, and collection devices using rotation to simulate gravity appear workable. Liquids have been identified which have low enough vapor pressures that evaporation losses over durations of tens of years are tolerable. Liquid tin is best for heat rejection between 500K and lOOOK, tin eutectics between 370K and 600K, and silicone oil between 260K
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