14th European Conference on Turbomachinery Fluid dynamics & Thermodynamics
The understanding of heat transfer and fluid motion in compressor rotor drums is a key piece of knowledge for highly efficient aero engines. Since rotor blade tip clearance is depending on the thermal growth of the discs, the prediction of the temperature and Nusselt number distribution of these structures is very important. Historically the calculation of heat transfer coefficients was done with respect to the inlet temperature of the air entering the cavity. This only leads to normalized heat fluxes. For a more accurate prediction of the heat transfer the air and metal temperature distribution of the cavity is needed. The latest published theoretical model for disc temperatures and Nusselt numbers takes the interaction of buoyancy driven flow with the recirculating air from the Ekman layer into account (Tang, Owen 2015,2017). This paper presents the results of a single cavity rig that consists of a pair of identical discs, a cylindrical shroud and a stationary inner shaft. The discs and the shroud of the rig can be heated individually to generate an axial gradient to the cavity as found in real engines. Disc and fluid temperature as well as static pressure measurements of the cavity are carried out by a two-sided telemetry system. The operating conditions are analogous to the available prior published data of the Sussex Multiple Cavity Rig. There are additionally new test conditions with asymmetric heating on top of the disc of cavity.