The influences of different cooling holes at different mass flow rates on film cooling effect were studied by researching the relationship between the film cooling hole shape and counter jet flowing. The CFD method was used to study 4 kinds of working conditions of the cylindrical hole

the shrinkage hole

the expansion hole and the shrinkage-expansion hole under flight height 50 km

flight Mach number 15 condition. Results show that: under the small mass flow rate

long penetration model (LPM) will occur in the shrinkage hole and the cylindrical hole

unlike the case of the expansion hole and the shrinkage-expansion hole. With the increase of the jet mass flow rate

the jet will change from LPM mode to short penetration model (SPM) mode

and the cooling benefit will not appreciably increase with the increasing jet mass flow rate. Considering the changes of the whole working states

the expansion hole is a relatively stable and reliable film cooling hole in the counter-jet film cooling.