Heat transfer analysis of supercritical CO2 in a High-Speed turbine rotor shaft cooling passage

Abstract

This study investigated the turbulent flow heat transfer in a high-speed turbine rotor shaft cooling passage using CFD. Supercritical CO2 is used as the coolant. The coolant temperature, heat transfer coefficient, convection heat transfer, and frictional heat transfer are investigated. The effect of clearance, mass flow rate, shaft rotational speed, and shaft temperature is also investigated. The result showed that the coolant temperature and heat transfer coefficient are independent of the radial clearance. The significant effect of mass flow rate on the coolant temperature is predicted. The convection heat transfer is substantially higher than the frictional heat transfer. This implies that the convection heat transfer is highly dominant over the frictional heat transfer by which the significant cooling provision could be achieved by the supercritical CO2 fluid through the annulus passage. A little agreement is found when the quantity of heat transfer is predicted using correlation and compared with the result obtained by CFD.