According to the heat transfer enhancement with vortex

experiments were performed to investigate the discharge coefficient of film outflow in narrow confined space

which the ratio of the internal cooling channel height to the diameter of film cooling hole (h/d) was smaller than 1.In experiments

the rules of discharge coefficient Cd varying with the film cooling hole Reynolds number (4800~26000)

blowing rate M(0.36~2.74)

dimensionless of film cooling channel height h/d(0.33~2.0)were studied in detail

and the similarity criteria for discharge coefficients varying with these parameters were concluded.The experimental results show that the film cooling hole discharge coefficient increase with the film cooling hole Reynolds number when the main flow Reynolds number is constant.In the constant film cooling hole Reynolds number cases

Cd increase with the blowing rate M rising especially when M is smaller than 1.It is also found in experiments that the Cd decrease with dimensionless of film cooling channel height h/d increasing

especially in the cases which the film cooling hole Reynolds number is larger than 9500.