An Analytical Study of Turbine Disks Incorporating Radially Rotating Heat Pipes

Abstract

Abstract In modern aero-engines, a turbine disk is normally cooled by compressed air bled from the engine compressor. A literature survey regarding the turbine disk cooling reveals that although the average air-cooling heat transfer coefficient is generally high, the local heat-transfer coefficient at the disk rim is low. Impinging jet cooling could be used to enhance the heat transfer at the rim, but its implementation is costly. One of the major causes of the high temperature at the rim is the low thermal conductivity associated with the turbine disk material. Based on this understanding, a turbine disk that incorporates radially rotating heat pipes has been introduced. The incorporation of the heat pipe would significantly increase the effective thermal conductance of the disk and spread the heat from the disk rim to a much large surface area, A unique disk design that employs interconnected heat pipe branches is also described for the purpose of cost reduction. To evaluate the effectiveness of the new turbine disk, a simplified analysis based on the one-dimensional and steady-state assumptions is made. The analytical results indicate that a disk that incorporates the heat pipe could reduce the disk rim temperature by more than 300°C, with only a moderate increase in the disk bore temperature. A turbine disk that employs rotating heat pipes is very effective for the disk rim temperature reduction. It also represents a new approach for cooling turbine rotor blades, and could find important applications in advanced gas turbines working at very high inlet temperatures.