Effects of wick structure and installation angles on the heat transfer characteristics of concentric annular heat pipes: Experimental investigation

Abstract

Thermal protection of the infrared sensor is critical in the temperature measurement of the turbine disk. One of the infrared sensors' most critical thermal protection structures is the Concentric Annular Heat Pipe (CAHP) due to its excellent heat transfer capability. In this study, specific CAHPs are designed with circumferential uniform wick (CUW) and circumferential grid wick (CGW) configurations according to the temperature measurement scenario of the turbine disk chamber. The effects of wick structure on the CAHP's startup characteristics and heat transfer performance are examined through experiments. Results show that, compared to CUW, CGW has a shorter startup time and smaller thermal resistance, but the critical heat flux is lower. Results also that, the circumferential temperature distribution at the evaporator of CUW is more uniform than CGW. An increase in the number of grids can enhance temperature uniformity. When the evaporator is positioned below the condenser, the thermal resistance of the heat pipe is lower, so this configuration is more suitable in engineering applications.

Keywords

• Concentric annular heat pipe
• Wick distribution
• Installation angles
• Infrared sensors thermal protection