Design and Validation of a Test Rig for Heat Transfer Measurements on a Rotating Cone

The paper presents the setup of a test rig to measure heat transfer coefficients on an actively cooled rear cone of a high pressure compressor. First results of an experimental heat transfer study on two different cooling assemblies are discussed. To derive local heat transfer coefficients on a rotating cone under varying engine related conditions, a new test rig was built at the Institut für Thermische Strömungsmaschinen in Karlsruhe/Germany. The test rig mainly consists of a rotating cone and an adjacent conical casing. The cooling concept consists of holes uniformly distributed around the circumference of the conical casing. Heat transfer measurements are performed in the gap between cone and casing whereby the gap width can be varied. The geometry of the cooling air supply holes can be modified by inserting different rings in the conical casing which include various cooling air geometries. The test rig operating conditions can be varied over a wide range of Reynolds numbers and air mass flow rates to cover the load ranges of several jet engines. Experimental results for the heat transfer of two different cooling air inlets are presented. An analysis of the measurement uncertainty is conducted. Errors are less than 10 %. Therefore, the results facilitate the design and optimization of the secondary air system of a high pressure compressor of a jet engine in terms of compressor rear cone cooling.