This document summarizes a collaborative investigation between the Pennsylvania State University and University of Minnesota on aerodynamics and heat transfer performed near the tip region and endwall of a turbine rotor blade with and without coolant ejection. For the design of gas turbines, designers need reliable flow and heat transfer information for the hot section components. Such information is still missing for several locations on the gas flow path which are exposed to deterioration and destruction by the hot gas. A recent research proposal from the University of Minnesota highlights three needed areas :

• Flow and Heat Transfer in the tip region of turbine blades.

• Heat Transfer caused by misalignment or leakage between turbine blades or with adjoining flow channels at the base region.

• Reduction of the strength of the horseshoe-passage-vortex system.

The current University of Minnesota study uses a linear cascade facility and special instrumentation for naphthalene sublimation based mass/heat transfer measurements as well as tracers in the fluid stream and on surfaces. The proposed investigation includes validation of CFD models by using the measured data. The computational models are then suggested to extend the range of conditions to high Mach numbers, large temperatures and high rotation rates. The final outcome of the Minnesota study is a set of design recommendations for industry. The details of the specific approach is explained in a proposal " Edge Cooling Heat Transfer on Turbine Blades," by R.J.Goldstein, S.V.Patankar and E.R.G.Eckert submitted to AGTSR, SCERDC (RFP No. AGTSR 97-01). The Pennsylvania State University currently operates a large scale Axial Flow Turbine Research Facility in its Turbomachinery Laboratory. The turbine rotor is instrumented for internal aerodynamics and heat transfer studies including cooling in the rotor frame of reference. The collaborative investigation was in the areas of assessing the additional effects caused by rotational effects in a turbine rotor frame of reference.

The organization of this report is as follows: chapter 2 describes the measurement facilities used in the University of Minnesota for flow and mass transfer measurements, and the flow visualization procedure. Chapter 3 presents the effects of tip clearance on the pressure distribution around the blade, and also gives flow visualization results. Chapter 4

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