Fabrication of Sodium/Inconel 718 Heat Pipes for Combustor Cooling

Cooling channel involved heat pipes, which synergistically combined the high conductivity of heat pipe and thermal efficiency of regenerative cooling, were considered for combustor cooling. In this study, cooling channels were fabricated in sodium/Inconel 718 heat pipes in China Academy of Aerospace Aerodynamics (CAAA). And their startup properties and thermal response were investigated systematically. It was found that the frozen startup limit of fabricated heat pipes were 2.60 and 2.76, satisfying the criterion for frozen startup. During startup tests, the sodium/Inconel 718 heat pipes startup successfully, displaying uniform temperatures of about 900 K and 830 K, respectively. Moreover, sodium/Inconel 718 heat pipes decreased operating temperatures and alleviated thermal stresses in combustor sidewalls. Under simulated Ma6 aerothermal environment, the operating temperature of sodium/Inconel 718 heat pipe was 1007 K, being 224 K lower than that of regenerative cooling model. Therefore, it was concluded that heat pipes could increase the thermal margin of regenerative cooling system, being suitable for applications in combustor cooling.