Abstract:
Rotor tip clearance (TC) is an importance parameter for the turbomachinery design and operation because of its contribution in loss and noise production. This study is focused on the effects of tip clearance on aerodynamic performance and tonal noise behavior of a single stage axial fan based on flow-field/acoustic-field hybrid model. The results indicate that the wake width and wake strength at the rotor exit increase with the tip clearance, but the phase distribution is almost unchanged; when the wake interacts with the stator, the rotor tip clearance increases unsteady loading fluctuation on the stator surface, but has little effect on its phase distribution. 2.5 mm TC lowers about 2% of the fan mass flow and about 1% of the fan efficiency, and also, it increases sound power level of 1BPF about 1.5 dB in the forward propagation and about 0.7 dB in the backward propagation. However, the influence of tip clearance on the tone noise intensity at 2BPF and 3BPF is more complex, and the variation range is less than 1 dB.