To explore the influence of thin wall size on film cooling performance

numerical simulation was carried out to investigate the flow field

temperature field and cooling effectiveness under conditions with wall thickness of one time

two times and three times of diameter of the film-cooling hole.The results show that

high-speed region appears at the hole exit with the wall thickness of one time of the hole diameter

resulting in an increase in the jet momentum and promoting the coolant being lifted off the wall.The lateral velocity of the coolant is towards to the center line of the hole

which weakens the spanwise diffusion.Compared with the wall thickness of three times of the hole diameter

the values of spanwise averaged film cooling effectiveness for one times of the hole diameter are about 9%~45%

21%~43% and 9%~62% lower at blowing ratios of 1.0

1.5 and 2.0

respectively.There is little difference in spanwise averaged film cooling effectiveness between the wall thickness of two times and three times of the hole diameter.