Summary

Low emission combustors produce turbine gas path radial temperature profiles which are relatively flat. This has resulted in endwall region over-temperature problems, specifically the blade and vane tip and platform regions. The desire to use less film cooling also puts an additional burden on the heat transfer design in these regions. Both data and comparison to CFD solutions are needed to provide a detailed and quantitative definition of both the complex 3-D flow and heat transfer phenomena.

The primary objective of this research is to investigate and quantify airfoil tip, platform and endwall region flow and heat transfer. Specific objectives include the acquisition and analysis of high-quality detailed data quantifying the complex flow in these regions in a research turbine with representative parameters, and comparison of these data to solutions obtained with state-of-the-art CFD tools.

Toward this end an investigation is performed on the first stage of the Purdue Research Turbine using Particle Image Velocimetry (PIV). The flow field is interrogated in the near-hub region of the intra-stage space, downstream of the first vane row. Purge air is introduced through a planar seal at three different flow rates which characterize the typical range of dimensionless seal flow rates encountered in practice. Two-dimensional (radial and axial) velocity data from four measurement planes spaced from vane pressure to vane suction side are acquired. These data are phase-locked to rotor position. The ensemble-averaged data from each rotor position provides a characterization of the effect of the rotor potential field on the emergent seal flow.

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