An Investigation of Secondary Cooling Effect on the Endwall Surface With Vane Trailing Edge Coolant Injection

Considering the adequate use of coolant, the secondary cooling effect of trailing edge coolant injection on the downstream endwall surface is investigated in this study. Distributions of adiabatic cooling effectiveness on the endwall surface are obtained through pressure-sensitive paint (PSP) technique in a linear cascade at four mass flowrate ratios (MFR = 1%, 2%, 3%, and 4%) and two density ratios (DR = 1.0 and 1.5). The configurations of trailing edge pressure-side cutback (PC) and central cutback (CC) with three compound angles (β = 15 deg, 30 deg, and 45 deg) are implemented in this study. Reynolds-averaged Navier-Stokes simulations are performed to present the flow field. Results show that the geometry of the cutback slot has a significant effect on the endwall cooling performance. As the compound angle increases, the coolant coverage is expanded in width. A higher density ratio leads to a decrease in the area of coolant coverage, while the distribution is more uniform. Generally, with a higher mass flow ratio, the coolant coverage is greatly improved in area and value, which almost covers the entire downstream endwall surface.