Search Results

When a permanent human outpost is established on the Moon, various methods may be used to reject the heat generated by the base. One proposed concept is the use of a heat pump operating with a vertical, flow-through thermal radiator mounted on a Space Station type habitation module [1]. Since the temperature of the lunar surface varies over the day, the vertical radiator sink temperatures can reach much higher levels than the comfort and even survivability requirements of a habitation module. A high temperature lift heat pump will not only maintain a comfortable habitation module temperature, but will also decrease the size of the radiators needed to reject the waste heat. Thus, the heat pump will also decrease the mass of the entire thermal system. Engineers at the Johnson Space Center (JSC) have tested a High Lift Heat Pump design and are developing the next generation heat pump based on information and experience gained from this testing.

The SHARE II (Space Station Advanced Radiator Experiment II) Mid-deck Experiment was flown on board the Space Shuttle (STS-37) from April 5 to 12, 1991. The purpose of the experiment was to demonstrate the operation of several design changes proposed for the NASA/Grumman SHARE II heat pipe as a result of the lessons learned during the first SHARE flight (STS-29) in March 1989. Two test articles flew during the mission. The first, the Bubble Management Test Article, was a Plexiglas model of the monogroove heat pipe. This test article was primarily used to evaluate the performance of two 0-g bubble management devices; the re-designed evaporator screen artery and the condenser bubble trap. The second, the Blended Manifold Priming Test Article, also constructed of Plexiglas, was used to demonstrate passive self-priming of a heat pipe blended manifold connecting three evaporator legs to a single condenser leg.

This paper presents the analytical results of a thermal hydraulic study to determine an “optimum” two-phase heat pipe/heat exchanger radiator panel configuration for the Space Station Freedom. The study was based on using conventional axially grooved heat pipes in combination with integral two-phase heat exchangers. Various design parameters were traded to arrive at an optimized panel design that satisfied the thermal requirements. For two-phase flow across a radiator array consisting of eight panels with fourteen heat pipes per panel, small diameter lines acting as flow restrictions are needed at the exit of each heat exchanger to balance the flow across each panel and the radiator array. The paper also presents the test results with a representative subscale heat pipe/heat exchanger radiator panel. In general, the heat pipes exhibit transport capabilities that exceed the design requirements. Balanced flow across each heat exchanger was also demonstrated.