Cavitation Effects on the Work of Disperse Sheet Collectors of Frameless Heat Removal Systems in Outer Space
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Journal of Engineering Physics and Thermophysics, Vol. 93, No. 6, November, 2020
HEAT AND MASS TRANSFER IN DISPERSED AND POROUS MEDIA CAVITATION EFFECTS ON THE WORK OF DISPERSE SHEET COLLECTORS OF FRAMELESS HEAT REMOVAL SYSTEMS IN OUTER SPACE A. A. Koroteev,a A. A. Safronov,b N. A. Safronova,c N. I. Filatov,b and A. L. Grigor′evb
UDC 532.529
The effects of cavitation processes on the work of the droplet collectors of frameless heat removal systems in outer space have been considered. The low cavitation steadiness of the centrifugal-type collectors has been substantiated. A procedure has been created for the calculation of flow characteristics of a belt-rotor droplet collector. A comparison has been made of the results of numerical calculation with the experimentally obtained characteristics of the functioning of such devices. Keywords: droplet collector, disperse sheet, droplet cooler–radiator. The solution of a number of problems of current importance for space science and exploration connected with the creation of multi-reentry systems of transportation of space vehicles to high orbits, removal of space debris, Earth′s remote sensing, etc. is impossible without using powerful space power units. Their creation is inevitably connected with solving the problem of removal of low-potential heat. Traditionally, this is solved using panel cooler–radiators. However, with a rise in power there is a rapid growth in the area of the radiating surface and meteoritic vulnerability of such systems. Armoring panel radiators is unacceptable, since this increases their mass significantly. The solution appears to be the use of a droplet cooler–radiator based on radiative cooling in space of a disperse flow of superhigh-vacuum heat-transfer agent formed in a special way [1]. The collection of cooled particles is carried out by a droplet collector wherefrom the collected working body (fluid) passes to a transfer pump returning the fluid to the hydrosystem of the droplet cooler–radiator. The space vehicle′s own outer atmosphere is rarefied. Thus, for example, near the international space station, during the work of the liquid rocket engines the pressure values do not exceed 10–1 Pa [2]. The effects of the forces of gravity and inertia on the liquid flow are negligible. Under these conditions, it is necessary to ensure a minimum pressure of the working fluid at the droplet collector outlet sufficient for steady cavitation-free work of the transfer pump. The value of this pressure is considered to be ~0.1 atm [3]. At present, the concepts of centrifugal and belt-rotor droplet collectors are the most developed. In centrifugal collectors, the droplet flow is received by the revolving surface with the formation of a fluid film on it which moves to the surface periphery under the action of centrifugal forces. As the fluid volume accumulated there rotates due to the action of centrifugal forces there occurs a pressure gradient used for the transfer of the working fluid. In the USA and Japan, investigations have been made into centrifugal
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