By using the NUMERCA software

the external heat exchange behavior of first-steage blades

such as the surface temperature of blades

the effectiveness of air film

and the distribution of heat exchange coefficient etc.

boasting many rows of air film orifices opened on them of one gas turbine has been calculated and numerically analysed

and the heat exchange behavior of blade cascade being numerically verified.It shows that the predicted value Nu tallies well with the tested value.On the pressurized area

the surface temperature of blades can be reduced by 40% on the average

the average effectiveness of air film being about 0.7;on the suction area

the temperature reduced 30% on the average

the average effectiveness of air film being about 0.5;but

the temperature on cord-length region relative to 20% of the pressurized area

at standing points on front edge and on the tail edge of the suction area was higher

and the effectiveness of air film being lower.The given external behavior of blades can be used as design basis of blades' internal structure;at standing point on front edge inside the blades and on the cord-length rigion relative to 20% of the suction area

impact cooling has to be used

increasing the flow rate of cooling air at tail edge of the suction area

reducing thermal load on said region

so as to make the blades to be uniformly cooled.