Study on full-coverage film cooling characteristics on turbine vanes under the effect of trailing-edge shock wave.

In transonic turbines, the oblique shock wave emanating from the stator's trailing edge impinges on the neighboring suction side, which has a complex effect on boundary layer flow. Numerical studies were performed to investigate the influence of oblique shock wave on suction-side film cooling, and the numerical results were validated by model experiments. The sudden increase of static pressure downstream of shock wave is adverse to coolant outflow, and cooling effectiveness shows a notable drop. Furthermore, injecting coolant into boundary layer can increase kinetic energy, and weaken flow separation caused by shock wave. Detailed influences of geometric and thermodynamic parameters on film cooling performance were analyzed. The increase of pressure ratio causes the downward motion of shock wave, which is beneficial to film cooling. The increase of hole size improves cooling effectiveness before shock wave, but reduces cooling effectiveness after shock wave. Cooling effectiveness decreases as hole inclination angle, hole pitch and spacing increases. Adding hole diameter or reducing hole inclination angle, hole pitch and spacing can increase discharge coefficient. Laminated cooling and film cooling were compared. By introducing jet impingement and pin fins, laminated structures can generate higher cooling effectiveness but lower discharge coefficient. [ABSTRACT FROM AUTHOR]