Numerical Investigation of the Effect of Part-span Sweep and Dihedral on the Performance of a Low-speed, High Hub-tip Ratio Axial Compressor Blade

摘要

The rear stages of an axial compressor suffer from larger effect of tip clearance related losses as the tip gap-span ratio is larger than the front stages of the compressor. This paper reports the effect of applying blade tip modifications for tip clearance loss management by means of sweep and dihedral. The performance benefits of applying non-radial stacking techniques namely, sweep and dihedral at the design point are highlighted. The simulations were performed using the commercial CFD package ANSYS CFX. The blade geometry chosen for the purpose of simulations is a high hub to tip ratio, low-speed blade, reminiscent of the rear stage blade of a multistage compressor. The performance benefits of sweep and dihedral are investigated. It is observed that certain orientations of sweep and dihedral result in significant benefits in terms of re-distribution of the blade loading and weakening of the tip leakage vortex strength.