Film cooling technique is one of the gas turbine components saving from thermal failure. This article presents a numerical
study of flm cooling efectiveness due to two rows of simple and compound angle holes. The holes are inclined with 30°
on a fat surface for all studied cases. Two orientation angles of the flm cooling holes are applied (0° and 30°). Six cases
are used to represent diferent confgurations for the two rows. Three diferent values of velocity ratios (namely 0.5, 1.0 and
2.0) are represented during this study. The numerical model is validated through comparing the results of single row with
simple holes with the available experimental works in the literature. As an interesting observation, it is found that the staggered arrangement provides better flm cooling efectiveness than the in-line one for zero orientation angle confgurations,
while the in-line arrangement represents the highest efectiveness if all holes in the two rows have 30° orientation angle.
The enhancement ratio of overall efectiveness corresponding to averaged flm cooling has been calculated. The maximum
enhancement ratio has been achieved with compound/compound in-line confguration with about 336.5% at velocity ratio
equal 2. Using compound angle holes enhances the flm cooling efectiveness with inline arrangement, while using it with
staggered arrangement reduces the overall averaged flm cooling efectiveness, especially at high velocity ratio. |
