摘要

In 2004-2006 the engineering model of a deploy able radiator based on a loop heat pipe (LHP) was developed. It was designed for qualification tests.
Application of ammonia as the LHP working fluid is attributable to its high thermal physical properties. However, the freezing temperature of ammonia is minus 77° C. This fact impedes the application of ammonia when the operating temperatures of the LHP radiator are lower than this value. Application of other working fluids with lower freezing temperatures (propylene, for example) leads to a rather substantial decrease in the heat power transferred or increase in the LHP dimensions and mass, which is not acceptable in many cases.
An important problem to be solved for ammonia LHP application is the recovery of the LHP operating capacity after the freezing of a working fluid in a radiator-condenser. To recover the working fluid circulation in an LHP, it is necessary to defreeze the entire LHP. During multiple freezing/melting cycles of the LHP working fluid, the LHP depressurization may occur. This paper is devoted to solving some aspects of the recovery of the radiator operating capacity after freezing.
The aspects of passive temperature control of the LHP evaporator using a pressure regulator and the aspects of the LHP active temperature control using heaters and Peltier elements mounted in the compensation chamber are also considered in this paper.
The development of new key components made it possible to design a deployable radiator with a specific mass of less than 10 kg/kW. The deployable radiator parameters are described in the paper.