Material Selection, Manufacturing and Performance Test of Ceramic High‐Temperature Heat Pipes Using Liquid Metals as Working Fluids

Abstract

Heat exchange applications at high temperatures of greater than 800°C under corrosive or abrasive conditions require heat exchangers based on ceramic materials instead of conventionally used metals. Heat exchangers based on heat pipes are exceptionally suitable since temperature gradients and correspondent thermal stresses are inherently low for this design. At high temperatures greater than 800°C, the structural material SSiC and working fluids sodium or zinc appear to be the most promising options. Encapsulating the working fluid in ceramic heat pipes with a sealing joint ensuring long term stability and high temperature resistance is particularly challenging. A nickelbased alloy has been identified as solder material for SSiC heat pipes using sodium as working fluid and a glass solder was used in case of zinc filled heat pipes. Manufactured heat pipes were tested in a hot-gas test rig at temperatures up to 1000°C.

Calculation Approach for Ceramic Heat Pipe Heat Exchangers for High‐Temperature Applications

“…Information on the manufacturing and filling of ceramic heat pipes and the special laser joining process can be found in , .…”

Micro Reactor Instrumentation and Control FY2019 Report

“…Heat pipes have been built and tested up to the temperature range of liquid metals, primarily using thermocouples to monitor temperature. The temperatures concerned were 600 °C for a space station test [22] and 1000 °C for a ceramic heat pipe test [23] (the latter also used a thermal camera). On a smaller scale, thin film thermistors and pressure transducers have been used on micro heat pipes meant for electronic circuits below 100 °C [24] [25].…”

Corrosion of laser joined silicon carbide in gasification environment

“…Recent research work has shown that SSiC is stable and does not react with the molten zinc. 16 Most promising is the use of glass filler systems. 17 Especially, silicate glasses of the systems…”

“…EDX mapping of outside of joint 1 (EG 002) after exposure at 9008C to gasifier atmosphere only (left) and ash (middle) compared to original state (right)16 Phase transition and crack formation caused by potassium and beginning crack propagation in joint 3 after exposure to gas atmosphere at 9008C [joint 3 (EG 2410), gas, outside]…”