Experimental and numerical investigation on the film-cooling a gas turbine vane pressure side with various internal rib angles

Abstract

To study the effects of the internal rib angles on the film cooling performance of turbine vane, a single row of film cooling holes on the pressure side was investigated using pressure sensitive paint (PSP) technology and numerical approaches. For the four internal ribbed cooling channels (smooth channel, 30°, 60° and 90° ribs), the distributions of film cooling effectiveness at three blowing ratios (0.3, 0.5, 0.8) and two density ratios (1.0, 1.5) were studied. Experimental results showed that the 30° rib is the most effective for most working conditions, followed by the smooth channel. When the blowing ratio (M) increases from 0.3 to 0.8, the film cooling effectiveness improvement of the 30° rib increases from 32.2% to 96.4% compared with the smooth channel. With the exception of slight variations at the local level, the area-average film cooling effectiveness for various angled ribs decreases as the blowing ratio increases within the scope of the experiment. The adherence of the cooling jet improves as the density ratio increases. For different angled ribs, the spanwise coverage of the film expands, the area with high cooling effectiveness expands, and the spanwise average film cooling effectiveness increases at the downstream regions of the film holes. With the increase of blowing ratio, the increment of density ratio on film cooling effectiveness is increased. The increment ratio for the smooth channel is the largest as the density ratio increased from 1.0 to 1.5 and it reaches 135 % when blowing ratio is 0.8. The film cooling effectiveness of film discharge for a turbine vane is systematically investigated with different rib configurations. The current study is useful for designing the pressure side of turbine vanes.