Ceramic Heat Pipes for High Temperature Application

Abstract

High temperature heat pipes with a ceramic container consisting out of sintered silicon carbide (SSiC) and with zinc as working fluid are investigated. To summarize the results, the performance of a singular bench-scale ceramic heat pipe (length 1,070 mm, outer diameter 22 mm) can achieve up to more than 1,000 W under test conditions. The best performance is reached with a filling amount of 100 g zinc as working fluid, which comes up to a filling height of about 11% of the total heat pipe length under liquid conditions. The present operating temperature of the heat pipes on the heating gas side could be tested up to 980 °C, so that the temperature inside the heat pipe, which is equal to the boiling temperature of the working fluid, has to be a little bit lower than that point. The pressure inside the heat pipe is beneath the ambient pressure at up to 907 °C working fluid temperature.