Measurements of vortex shedding and wake decay downstream of a turbine inlet guide vane

Abstract

The flow in the second stage stator of a gas turbine with contoured end-wall is measured in a low speed wind tunnel. The investigation is focused on the flow in proximity to the blade trailing edge and in the wake. The measurements include mean velocity, total and static pressure at the cascade exit together with the analysis of intensity and spectral characteristic of turbulence. Measurements have been carried out using a miniaturized five-hole pneumatic probe developed in-house and a single hot wire anemometer on a measurement grid covering different distances from the blade trailing edge. The very fine measurement grids allow a detailed description of secondary flows and the possibility to trace the development of the vortex structures in the trailing edge region. The combined use of the pneumatic probe and of the hot-wire measurements allow to get a wide set of information on mean and turbulent characteristics of the three-dimensional flow at the exit of the cascade and identify the changes in the flow at different blade spans.