A numerical study on effects of swirling coolant on film cooling performance is conducted for cylindrical, clover shaped and compound angle holes on a gas turbine endwall model. Various swirl numbers and positive and negative swirling direction of the swirling coolant jet are attained inside a swirl chamber by adjusting two small jet holes, which are installed on the swirl chamber bottom wall and incline at a certain jet angle to vertical direction. Reynolds-averaged Navier-Stokes (RANS) with SST k-omega turbulence model simulation is performed at a constant density ratio of 1.5 and a range of blowing ratio from 0.5 to 1.5. Compared with the case for non-swirling coolant, the results show that properly applying swirling motion into the coolant could dramatically improve the filth cooling effectiveness for the three types of typical film holes. The film cooling effectiveness of the compound angle film hole is sensitive to not only the swirling strength but also the swirling direction. Heat transfer with film cooling is more or less enhanced by swirling jet in the case of cylindrical and clover shaped film holes, while the heat transfer enhancement by injection could be reduced by swirling jet at high blowing ratio for the compound angle film hole. The reduction of net heat transfer to the endwall with film cooling can achieve its maximum value at jet angle of theta = +/- 20 degrees for the clover shaped hole, while as to the cylindrical and compound angle holes it depends on blowing ratio and swirling direction. (C) 2015 Elsevier Ltd. All rights reserved.