NUMERICAL RESEARCH ON THE INFLUENCE OF DIFFERENT SLOT CONFIGURATIONS ON FILM COOLING CHARACTERISTICS

摘要

Numerical approach has been conducted to compare the cooling and aerodynamic performance of different film cooling holes with one end or both ends embedded in transverse slots. The influence of different slot configurations with the same trench depth on the adiabatic cooling effectiveness and discharge coefficients from the point of view of flowing mechanism was revealed. The results show that: (1) Making the film holes embedded in transverse slots can improve the film cooling effectiveness. At low blowing ratio, the inclined trench is superior, at high blowing ratio, narrow trench wins; (2) Compared to the baseline untrenched configuration, the rectangular trench increases the aerodynamic loss, while the inclined trench along the streamwise direction avail the decrease of the aerodynamic loss.; (3) The cooling performance and the aerodynamic performance of the holes with both ends embedded in inclined slots is superior to the holes with only exit trenched. (4) Because of the interaction between the mainstream and injected fluid, a pair of taper vortex appears in the narrow trench, a column vortex appears in the wide trench, and a pair of counter rotating vortex appears in the inclined trench. Taper vortex and CRVP avail the lateral diffusion of the coolant flow, but the rotation of the column vortex goes against it. (5) The trailing edge wall of the trench plays an important role in the lateral diffusion of the cooling film, and the upstream edge of the trench plays an important role in the protection of the lateral diffusion of the cooling film.