Research and development of heat pipe with ampule filling

Heat pipes are successfully used for thermal control systems of spacecrafts for more than fifty years. Heat pipes start working immediately after filling with the fluid and transfer heat flow from the hot zone to the cold one, equalizing the temperature along the entire length of the heat pipe. There are tasks in spacecraft thermal control systems that require the heat pipe not to transfer heat until a certain time point, but to start working on a command from the onboard control system. Heat pipe with ampule filling is one of the possible ways to solve the problem. In the evaporator zone there is a welded ampoule-reservoir, which contains the main part of the work fluids. The fluid in the reservoir is separated from the main volume of the heat pipe by a sealed membrane. The membrane may be destroyed by heating the fluid in the reservoir. After the membrane destruction, the fluid enters the main volume of the heat pipe. Heat pipe with ampule filling created on the basis of an axial groove heat pipe with Ammonia. The paper will present the results of thermal tests of a heat pipe and the procedure for optimizing the mass of the fluid. The Reservoir is made of stainless steel and is connected to the heat pipe body by welding through a bimetallic connector. The membrane is made of Nickel. The thickness of the membrane was determined based on the required temperature 95�10oC. The results of the experiments and their analysis will be presented in the paper. The created heat pipe is used in the service thermal control system of the Russian meteorological satellite.