Experimental study of the effect of a transverse trench depth on film cooling effectiveness

The experimental results of film cooling effectiveness of a wall gas jet injected through inclined cylindrical holes into a transverse trench are presented. Measurements were carried out using IR thermography. The results of film cooling effectiveness through holes embedded into a trench were compared with the traditional well-known method of cooling with injecting without a trench. The thermal efficiency of the wall jet is much higher when injecting through the holes into the trench than the corresponding value when the wall jet is fed through inclined holes without a trench (the maximal value is more than 3 times higher). The particular advantage of this method of coolant supply is achieved at high injection parameters. The results of our measurements are compared with the experimental and numerical data of other authors, and a reasonable agreement is obtained.