Effect of Hydrogen Combustion on Film Cooling Characteristics in Gas Turbines

Abstract Hydrogen gas turbines offer a promising solution for carbon-free power generation. This study investigates the impact of hydrogen combustion on turbine-side cooling by numerically analyzing film cooling characteristics through coupled combustion and fluid dynamics simulations. Thermophysical property changes induced by hydrogen combustion were incorporated using combustion results and a realistic mixing model for mainstream gas properties. Constraints were carefully chosen to enable accurate comparison. Six scenarios of methane-hydrogen blending ratios (HBR) by volume fraction were considered, and species transport equations were solved to model the mixing of combustion gas and cooling air. Two blowing ratios were examined to assess the film cooling dynamics for each HBR case. The results show that increased HBR reduces density, promoting coolant liftoff at the leading edge and pressure side holes, leading to lower overall film effectiveness for higher HBR cases. On the suction side, where liftoff is weak, the increased specific heat capacity of the mainstream further reduced film effectiveness. Overall, hydrogen combustion reduces film cooling efficiency, highlighting the need for advanced cooling techniques in hydrogen gas turbines. These findings and the proposed framework can serve as a basis for future studies on hydrogen gas turbine film cooling.