Total pressure losses from planar Particle Image Velocimetry data: A practical approach for accurate wake flow assessment at turbomachinery-relevant Mach & Reynolds numbers

This work presents a hybrid approach for determining total pressure fields, which were reconstructed from Particle Image Velocimetry data and whose accuracy was raised through in-situ correction with probe-based reference data. The quality of this general approach is validated for turbomachinery-relevant Mach and Reynolds numbers using a cylinder in crossflow as a test case. Furthermore, the approach is applied to investigate the total pressure losses in the wake of a lowpressure turbine cascade. It is shown that the hybrid approach delivers total pressure loss fields over a wide Reynolds and Mach number range, which deviate from the highly accurate integral loss coefficients of a conventional loss traverse with probe-based measurement techniques for compressible flows by an absolute maximum of less than 2 %, but which delivers results at a much higher level of spatial resolution. For incompressible flows, the deviations are almost negligible at 1%. The paper presents and discusses the exact methodology for both, the collection of experimental data and the outline of the developed approach.