EXPERIMENTAL INVESTIGATIONS FOR EFFECTIVENESS OF COMBINED IMPINGEMENT FILM COOLING

Abstract

Protecting the gas turbine blades from high-temperature gases and increasing the specific work output is one of the most challenging tasks for most gas turbine design engineers. Combined impingement and film cooling can be used as a hybrid cooling technology to improve the film cooling performance over the gas turbine blade surfaces. In the present work, experimentations were performed on a flat plate with combined impingement film cooling for two thermally conductive materials (Perspex and stainless steel) at different blowing ratios and compared with the computational results. Thermo chronic liquid crystal sheets were used for measuring the temperature distribution. Effectiveness is the parameter that plays a vital role in determining thermal performance. Uniform effectiveness distribution was observed in stainless steel material because of its more thermal conductivity. Combined impingement film cooling showed higher effectiveness compared to film cooling. Uncertainty of ± 7% present in TLC data and experimental results agreed with the computational results.