Experimental investigation of conjugate heat transfer in a rib-roughened trailing edge channel with crossing-jets

The present contribution is devoted to the experimental study of the conjugate heat transfer in a turbine blade cooling cavity located near the trailing edge. The cooling scheme is characterized by a trapezoidal cross-section, one rib-roughened wall and slots along two opposite walls. The Reynolds number, defined at the inlet of the test section, is set at 67500 for all the experiments. The values of all the important non-dimensional parameters characterizing the experiment, including the solid-to-fluid conductivity ratio, are engine-representative. Uniform heat flux is imposed along the outer side of the rib-roughened wall. The measurements are performed using three different ribbed walls, with thermal conductivities ranging from 1 to 18 Wm-1K-1. Highly resolved distributions of non-dimensional temperature and Nusselt number over the rib-roughened wall are obtained by means of infrared thermography and finite element analysis. The impact of the conduction through the wall on the thermal performance is demonstrated by comparison with purely convective results, previously published by the authors on the same configuration.