Experimental Study on Aerodynamic Loss and Heat Transfer for Various Squealer Tips

This paper presents aerodynamic loss data for five squealer configurations of a full squealer (FS), a pressure-side squealer (PS), a suction-side squealer (SS), a camberline squealer (CS), and a full-camberline squealer (FCS) in a low-speed turbine cascade. In addition, tip thermal load data are also reported for the FS, PS, and SS tips. The results show that when h/s (tip clearance-to-span ratio) ≥ 0.96%, the mass-averaged loss for the FS tip decreases, has a minimum value, and then increases, as the squealer height (hst) increases. for h/s = 0.48%, however, the loss changes with hst/s are found to be minute. For the FS tip, the loss tends to increase, as the squealer thickness increases. Adding a camberline squealer to the FS tip is not beneficial in the loss reduction. When hst/s < 3.82% for h/s = 0.96%, the FS tip has the lowest mass-averaged loss, the SS tip has the second-lowest loss, the PS tip has higher loss compared to the SS tip, and the CS tip loss is highest, regardless of hst/s. For h/s = 0.96%, the average tip thermal load for the FS tip is lower than the PS tip one but is higher than the SS tip one. Thus, the SS tip delivers the lowest average thermal load, irrespective of hst/s.