Modeling film-coolant flow characteristics at the exit of shower-head holes

Abstract

Abstract The coolant flow characteristics at the hole exits of a film-cooled blade are derived from an earlier study where the hole pipes and coolant plenum were also discretized. The blade chosen is the VKI rotor with three staggered rows of shower-head holes. The present analysis applies these flow characteristics at the shower-head hole exits. A multi-block three-dimensional Navier–Stokes code with Wilcox's k – ω model is used to compute the heat transfer coefficient on the film-cooled turbine blade. A reasonably good comparison with the experimental data as well as with the more complete earlier analysis where the hole pipes and coolant plenum were also gridded is obtained. If the 1/7th power law is assumed for the coolant flow velocity and temperature distributions at the hole exits, considerable differences in the heat transfer coefficient on the blade surface, especially in the leading-edge region, are observed even though the span-averaged values of h match well with the experimental data. This calls for spatially-resolved experimental data near film-cooling holes on a blade for better validation of the code.