Numerical study of film cooling characteristics on a rotating turbine blade model

Computations are performed to simulate the flow and heat transfer characteristics of film-cooled rotating turbine blade models under different operating conditions. The chosen blade is a mid-span segment of a typical turbine rotor with two rows containing 14 staggered injection holes on both leading surface and trailing surface. The inclination angles to the leading and trailing surfaces are φ=30°, 60° and 90°, respectively. Detailed distributions of adiabatic film cooling effectiveness, Nusselt number and discharge coefficient on the leading and trailing surfaces are presented at various values of averaged blowing ratio, mainstream Reynolds number, and rotation number. Results show that the coolant is strongly influenced by the centrifugal force and Coriolis force to deflect toward the high-radius locations beside the leading surface, and this will lead to lower adiabatic effectiveness. The high values of blowing ratio are not suitable for the thermal protection near the exit of cooling holes, and the enhancement of Reynolds number can reduce the adiabatic effectiveness slightly. For discharge coefficient distributions, all the coefficients decrease with the increase of rotation number and increase with the augmentation of blowing ratio. Moreover, the discharge coefficient values beside the trailing surface are much higher than that beside the leading surface under the same operating conditions.