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This paper presents the heat transfer characteristics of a Reservoir Embedded Looped Heat Pipe (RELHP) with stainless steel porous wick with pore diameter of 1μm and working fluid of ammonia. The core of evaporator is used as a liquid reservoir to enhance operational reliability. Mathematical models for predicting static and transient heat transfer characteristics of RELHP were developed. Evaporative heat transfer coefficient in wick and heat transfer between vapor phase and liquid puddle in reservoir are taken into consideration in these models. Experiments using the reservoir visual inspection model and practical RELHP were conducted and compared with the prediction. The evaporator of the practical model has the length of 1000mm and diameter of 38mm and the total loop length is 11.5m. The practical RELHP model has the same configuration, as that will be experimented in ETS-VIII.

This paper presents a design of deployable radiator and engineering model test for ETS-VIII (Engineering Test Satellite VIII). ETS-VIII will be launched in 2003, which establishes and verifies an advanced 3-ton-class spacecraft bus and an advanced communication technology via satellite. Developed deployable radiator uses LHP (Loop Heat Pipe) whose reservoir is embedded in an evaporator (RELHP) and wick is 0.5 micron fine pore radius stainless steel. Further, CFRP (Carbon Fiber Reinforced Plastic) face-skin with high thermal conductive graphite fiber is used for panel face-skin to reduce panel thickness as well as the panel weight. Thin panel is necessary to reduce stowed panel space. RELHP (Reservoir Embedded Loop Heat Pipe) condenser, aluminum alloy channel, is embedded in the CFRP face-skin radiator panel. Further, engineering model test of the developed deployable radiator has already finished.

Nowadays, it becomes more important to predict the heat transport capability of axial grooved wick heat pipes with asymmetrical heating accurately. The authors succeeded in calculation by applying transient analysis. It was found that the heat transport limit is the point where all the grooves began to have dry out region. The prediction of the heat pipe agreed well with the test data with asymmetrical heating under micro-gravity as well as under normal gravity. In addition, it also showed there is no marked difference between symmetrical heating and asymmetrical heating to extent of tested heat pipe design.