Heat Pipe Cooling of Turboshaft Engines

Abstract

Reduction in turbine engine cooling flows is required to meet the IHPTET Phase II engine performance levels. Heat pipes, which are devices with very high thermal conductance, can help reduce the required cooling air. A survey was conducted to identify potential applications for heat pipes in turboshaft engines. The applications for heat pipe cooling of turbine engine components included the power turbine first stage vanes, shroud, and case, the HP turbine vanes and shroud, and the T5 temperature probe. Other potential applications for heat pipe cooling include regenerative cycle and intercooling, bearing cooling, IR signature reduction, and active clearance control. Calculated performance benefits included an increase in specific shaft horsepower, and a decrease in specific fuel consumption, as determined with an IHPTET Phase II turboshaft engine performance model. For example, using heat pipes to cool the power turbine vanes, shroud, and case would increase the specific shaft horsepower by 6 percent, while decreasing the specific fuel consumption by 2.2 percent. While this study examined turboshaft engines, most of the applications are also applicable to turbofan engines.