An Investigation on the Effect of Blade Tip Clearance on the Performance of a Single-Stage Axial Compressor

In the present study, the numerical analysis of blade tip geometry effect on the performance of a single-stage axial compressor has been the focus of attention. The studied geometries included a rotor with variable tip clearance. For the first model, the tip clearance increases as it moves toward the blade trailing edge. The tip clearance of the second model reduces as it approaches the trailing edge, whereas in the third model, the tip clearance remains constant. The results indicated that the tip clearance of the first sample, as the worst tip clearance case, creates a ۱۰% reduction in the stall margin with respect to the third standard model, and the second sample tip clearance brings about a stall margin reduction of ۴% efficiency with respect to the third standard model. Then, the effect of blade tip clearance geometry on outlet flow angle of the rotor was inspected. The results showed that in the first model, the outlet flow angle has the largest deviation than the third standard model and the second model performance places somewhere between the two other tip clearance geometries. Also evident from the result is that taking advantage of the variable blade tip clearance is not an appropriate method for improving compressor performance.

Keywords:

Axial compressor , Variable tip clearance , Stall margin , Flow angle , Compressor performance