Experiments were performed to study the effect of film hole location on local heat transfer coefficient distribution of a turbine blade model with air or CO2 film injection to simulate coolant density effect. Tests were performed on a five blade linear cascade at the chord Reynolds number of 3×105 at cascade inlet. The test blade had three rows of film holes in
the leading edge region and two rows each on the pressure and suction surfaces. Film hole
locations were varied by leaving the desired ones open and plugging the rest. A combination
of turbulence grid and unsteady wake was used to generate upstream high turbulence
condition. Results indicate that film injection by itself causes a substantial increase in
Nusselt numbers over a blade model without film holes. An increase in mainstream
turbulence intensity causes an increase in Nusselt numbers over most of the blade surface,
for both coolants, and at all blowing ratios. Film injection promotes an earlier boundary
layer transition on the suction surface and the onset of transition depends on the film
injection location; but at high turbulence levels, transition location is almost independent of
film injection location.
