Upstream and Passage Endwall Film Cooling of a Transonic Turbine Vane

Abstract

Adiabatic film cooling effectiveness was measured on the endwall of a turbine vane under transonic flow conditions using binary pressure-sensitive paint. The combined effect of upstream and passage film cooling holes was evaluated. The experiments used a five-vane annular cascade in a blowdown wind tunnel. The mainstream velocity was set to exit isentropic Mach numbers of 0.7 and 0.9. The total coolant-to-mainstream mass flow ratio (MFR) was varied from 0.75 to 2.50%. Coolant-to-mainstream density ratios (DRs) of 1.0 and 2.0 were investigated. The first row was located upstream of the vanes, and the second and third rows were located in the passage between the vanes. Coolant was supplied by a divided plenum, allowing independent control of the MFR to the upstream and the passage holes. The coolant MFR was evenly split between the upstream and passage holes. Generally, increasing the MFR, the DR, and the Mach number increased the film cooling effectiveness. However, increasing the DR at MFRs of 0.625% and below decreased the laterally averaged film cooling effectiveness by as much as 60%, largely because mainstream flow was ingested through the second row. Upstream coolant provided some protection through the passage, with effectiveness as high as 0.2 at the second row.

Experimental Study on the Improvement of Film Cooling Effectiveness of Various Modified Configurations Based on a Fan-Shaped Film Cooling Hole on an Endwall

“…The measurement of adiabatic film cooling effectiveness was conducted using Pressure Sensitive Paint (PSP), as previously employed in the study by Kim et al [22]. Pressure-sensitive paint has been utilized in various studies for conducting film cooling measurement experiments [4][5][6][7][8][9][20][21][22][24][25][26][27]. PSP has the characteristic of changing luminescence intensity based on the surface oxygen partial pressure when exposed to specific frequencies of light.…”

Numerical Study of Endwall Modification with Micro-Scale Ribs in a Turbine Cascade

“…Chen et al [12] numerically studied the effects of a cooling jet in a special position to counter the horseshoe vortex of an LE leg. Burdett et al [13] carried out experimental research on a contour endwall with upstream holes. The results showed that the negative effect of the PV on cooling could be inhibited when the mass flow ratio (MFR) of the upstream coolant was more than 0.75%.…”