Midline Heat Transfer and Pressure Measurements on an Incident Tolerant Blade Section for a Variable Speed Power Turbine at Low to Moderate Reynolds Numbers in a Transonic Turbine Cascade

Abstract

Midspan heat transfer and pressure measurements have been acquired in a steady state transonic linear cascade at low to moderate Reynolds numbers. These results were used to investigate boundary layer development and separation on a 2-D variable-speed power turbine rotor blade. These distributions were acquired at 8 separate incidence angles ranging from +5.8 to – 51.2. At each angle measurements were acquired at four Reynolds numbers ranging from 50,000 to 568,000 based on true chord and exit conditions. These four Reynolds number cases were tested at the design exit Mach number of 0.72. Reynolds numbers of 228,000 and 568,000 were also run for selected angles at an exit Mach number of 0.35 to constitute match points for similar measurements which were conducted at NASA Glenn. These measurements were conducted at both a lower (~0.4%) and a higher (~4%) turbulence condition. The surface pressure distributions are plotted in terms of local isentropic Mach number. They show changes in loading, the movement of the stagnation line, and regions of separation with changing incidence angle and Reynolds number. Heat transfer measurements show areas of laminar flow, regions of transition, locations of separation as well as information on reattachment.