GAS CYCLE COOLING SYSTEMS FOR SPACE VEHICLES

摘要

The large weight penalties (imposed by radiators on space vehicles require that every effort be made to reduce radiator size. The primary purpose of this study was to determine the conditions at which gas cycle cooling systems required the smallest radiators, and to compare these radiator sizes with that required for a simple passive cooling system (a system transporting heat from vehicle compartments to a radiator by natural means). Performance characteristics of gas cycle systems were determined to establish radiator sizes. The radiator area required for the power unit needed to drive the gas cooling systems was also determined. In calculating the radiator sizes for a one kilowatt cooling load, the power unit's radiator temperature was held constant at 700°F while the cooling system's radiator temperature was varied from 58°F to 950°F. Cooling systems providing temperature control for both cabin and electronic equipment compartments were considered. Both air and hydrogen, representing- low & high specific heat gases respectively, were evaluated. Radiator size decreased with an increase in radiator temperature, but when the radiator area required for a power unit to drive the cooling system was considered, the total radiator area increased with an increase in radiator temperature. Since the smallest radiator was obtained with the simple passive cooling system, gas cycle cooling systems were considered undesirable for space vehicle applications.