Profile and secondary flow losses in a high-lift LPT blade cascade at different reynolds numbers under steady and unsteady inflow conditions

Abstract

The aerodynamic flow field downstream of a Low-Pressure High-Lift (HL) turbine cascade has been experimentally investigated for different Reynolds numbers under both steady and unsteady inflows, in order to analyse the cascade performance under real engine operating conditions. The Reynolds number has been varied in the range 100000<Re<300000, where lower and upper limits are typical of cruise and take-off/landing conditions, respectively. The effects induced by the incoming wakes at the reduced frequency f +=0.62 on both profile and secondary flow losses have been investigated. Total pressure, velocity and secondary kinetic energy distributions at the downstream tangential plane have been measured by means of a miniaturized 5-hole probe. These quantities provide information on both blade wake and secondary flow structures (passage and horse-shoe vortices). The analysis of the results allows the evaluation of the aerodynamic performance of the HL front-loaded blade in terms of both profile and secondary losses.