Blade Tip Leakage Flow and Heat Transfer with Pressure-Side Winglet

[摘要] A numerical study has been conducted to explore the effect of apressure-side winglet on the flow and heat transfer over a bladetip. Calculations are performed for both a flat tip and a squealertip. The winglet is in the form of a flat extension, and is shapedin the axial chord direction to have the maximum thickness at thechord location, where the pressure difference is the largestbetween the pressure and suction sides. For the flat tip, thepressure-side winglet exhibits a significant reduction in theleakage flow strength. The low heat transfer coefficient“sweet-spot” region is larger with the pressure-side winglet,and lower heat transfer coefficients are also observed along thepressure side of the blade. For the flat tip, the winglet reducesthe heat transfer coefficient locally by as much as 30%, whilethe average heat transfer coefficient is reduced by about 7%.In the presence of a squealer, the role of the winglet decreasessignificantly, and a 5% reduction in the pressure losscoefficient is achieved with the winglet with virtually noreduction in the average heat transfer coefficient. On the otherhand, the suction-side squealer with constant width winglet showslower heat transfer (reduction of 5.5%) and pressure losscoefficient (reduction of 26%) than its baseline counterpart.

[学科分类] 力学，机械学