A New Method to Investigate Unsteady Heat Transfer in a Turbine Research Rig

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One of the most difficult areas of experimental heat transfer is that of determining the thermal response of solid surfaces placed inside the flow to highly non-steady fluctuations in temperature, pressure, velocity, etc. In recent years, very sophisticated computer codes have been developed which are capable of analyzing such flows, but typically, they involve some semi-empiricism. Experimental validation of these non- steady codes is therefore of great importance. However, the progress of experimental techniques has not kept pace with such computational developments, and much work is needed to provide such validation. One area where non-steady effects are of great importance is the area of turbo-machinery where high non-steadiness is produced by rotor-stator flow interactions, shock wave generation, turbulence, blade-boundary layer interaction, and the like. The Axial Flow Turbine Facility at Penn State with its instrumentation in the rotor frame of reference is uniquely equipped to attempt such validation. The innovation of the proposed research is to attempt to simulate non-steady heat transfer in a turbo-machine by introducing a slug of high temperature air flow at a relatively small segment of the periphery of the turbo- machine, over a very small increment of time. If the simulation proves valid, then the experimental study of non-steady transfer characteristics in turbo-machines will be greatly simplified, and lead to relatively rapid progress in this important field. In addition, fundamental information on non-steady heat transfer will emerge from this study.