EFFECT OF MAINSTREAM ACCELERATION ON ADIABATIC WALL TEMPERATURE AND HEAT TRANSFER DOWNSTREAM OF GAS INJECTION.

The local film cooling effectiveness and the heat transfer downstream of air injection through a single hole and two staggered rows of holes are measured. The mainstream velocity increases by factors of either 1. 8 or 3. 0 over the length of the test plate, which extends fifty hole diameters downstream of injection. The mainstream acceleration increases the effectiveness downstream of the single hole while it decreases the effectiveness from the staggered rows by about 15%. The heat transfer coefficient normalized by the heat transfer coefficient without injection is not affected by acceleration at low blowing rates. At higher blowing rates a slight drop in normalized heat transfer coefficient is observed.