Particle image velocimetry and particle scattering measurements are taken over a flat multi-row film cooled surface. The effect of coolant mass flow (characterized by blowing ratio, momentum flux ratio or velocity ratio) is investigated. The array investigated has 8 rows containing 52 holes of 3.8 mm diameter with inclination angles of 20° and hole length-to-diameter ratios of 11.2. The lateral and streamwise pitches are 7.5 times the diameter. The holes are in a staggered arrangement.
PIV measurements are taken with CO2 as coolant injecting into an air primary stream. Two streamwise aligned planes are measured; a centerline plane and a plane spaced laterally half a diameter from centerline. The PIV results provide a quantitative view of the flow over eight rows of injection as well as the recovery region. Images are acquired at 8 Hz and have a spatial resolution of 10.3 interrogation windows per hole diameter. The tunnel has low freestream turbulence (1%) and is low speed, so the primary turbulence production mechanism is shearing. As a result, the M = 0.45 blowing ratio case shows higher levels of turbulent kinetic energy compared with the M = 1.05 blowing ratio case. Uncertainty in the PIV measurements is estimated via the correlation statistics method.