Numerical Study of Film-Cooling Performance on a Rotating Model

摘要

Flow characteristics, adiabatic effectiveness, and discharge-coefficient distributions are numerically investigatednon a rotating film-coolingmodel under different operating conditions. The computationalmodel originates fromthenmidspan section of a typical turbine rotor with two rows of 14 staggered injection holes angled at 30, 60, and 90 deg,non both the suction surface and pressure surface, and the flowthrough the coolant plenumand all of the hole pipes arenresolved as a part of the computational domain by specifying the coolant mass flux in the plenum. The commercialncomputational fluid dynamics code Star-CD with structured body-fitted grids is employed for the computations, andnthe Wilcox u0001-! model is chosen for turbulence closure. In the present study, the Reynolds number Re based onnmainstreamvelocity and injection-hole diameter varies from1835 to 5507, and the averaged blowing ratioM rangesnfrom 0.5 to 1.5. Results show that the coolant will move to the high-radius locations near the suction and pressurensurfaces due to the strong centrifugal effect, which leads to the decrease in adiabatic effectiveness accordingly. Thendischarge coefficients Cd on the pressure surface are much higher than those on the suction surface under a givennoperating condition. In addition, the critical values of angular speed that represent the equilibrium of centrifugalnforce and Coriolis force near the pressure surface are also presented in this paper.