Turbulence and Heat Transfer Measurements in an Inclined Large Scale Film Cooling Array: Part II—Temperature and Heat Transfer Measurements

The second of a two-part paper, this study focuses on the temperature field and surface heat transfer measurements on a large-scale models of an inclined row of film cooling holes. Detailed surface and flow field measurements were taken and presented in Part I. The model consists of three holes of 1.9-cm diameter that are spaced 3 hole diameters apart and inclined 30° from the surface. Additionally, another model with an anti-vortex adaptation to the film cooling holes is also tested. The coolant stream is metered and cooled to 20°C below the mainstream temperature. A thermocouple is used to obtain the flow temperatures along the jet centerline and at various streamwise locations. Steady state liquid crystal thermography is used to obtain surface heat transfer coefficients. Results are obtained for blowing ratios of up to 2 in order to capture off-design conditions in which the jet is lifted. Film cooling effectiveness values of 0.4 and 0.15 were found along the centerline for blowing ratios of 1 and 2 respectively. In addition, an anti-vortex design was tested and found to have improved film effectiveness. This paper presents the detailed temperature contours showing the extent of mixing between the coolant and freestream and the local heat transfer results.