LAUSR

Abstract A wake is induced in turbine passages due to the interaction of turbine stators and rotors. Each stage of the turbine blade has different geometric parameters, namely, the turning angle, leading edge radius, and solidity, which all vary. Comparison of flow and thermal characteristics between the first and second-stage blades was carried out. The flow and thermal characteristics of the first-stage blade endwall were investigated for various Strouhal numbers to determine the wake effect. Numerical simulations and experiments were performed to compare the flow and thermal characteristics of the different stage blades. Experiments were performed using a five-bladed linear cascade with moving cylindrical rods simulating the wake effect. The effective area and strength of secondary vortices differed in each stage of blade, which resulted in different local heat transfer distributions. In addition, the local heat transfer characteristics changed depending on the Strouhal number. The ‘without wake’ case ( St  = 0) showed non-uniform heat transfer distribution on the endwall with the occurrence of horseshoe, passage and corner vortices. The ‘with wake’ effect cases ( St  ≠ 0) showed a more uniform heat transfer distribution on the endwall. The wake effect disturbs the occurrence of secondary vortices. With an increase in the Strouhal number, the endwall is exposed to higher thermal load.