Arvind Pattamatta

The main objective of the present work is to study the effect of lip thickness and the lip cross section on the fluid flow behavior and effectiveness in tangential film cooling in a combustor liner. A three-dimensional jet exiting from a circular hole of diameter 2 mm is considered as coolant and the hot mainstream as a co-flow. The coolant and the mainstream are separated by a thick slab called the lip. A three-dimensional, steady-state numerical study is performed for different lip thicknesses (t) ranging from 0.25D to 2.5D and a blowing ratio of 0.5, 0.9, 1.5, and 2.5. Results are presented for a dimensionless stream-wise distance between 0 and 35. At all blowing ratios, a lip thickness of 0.25D (thin lip) performs better than the other lip thicknesses under consideration due to the attached flow. Additionally, it is observed that a change in the cross section (tapered) of the lip shows improvement in the film effectiveness, which may be attributed to the Coanda effect.