Discrete frequency noise reduction of the cross-flow fan of the split typeroom air-conditioners using the skewed stabilizers

The cross-flow fan system of the split type room air-conditioners often gen erates the discrete noise component that is called the (B) under bar lade ( P) under bar assing (F) under bar requency tone. It has been known that the BPF tone is generated due to the fluctuating pressure field of the aerodyn amic interaction between the rotating fan blades and the stationary stabili zer (or cut-off). Several methods have been invented to reduce this BPF noi se. One of the promising schemes is to skew the stabilizer with respect to the fan blade span, which shifts the phase of the pressure fluctuations alo ng the fan span. In this study some experiments have been carried out to in vestigate influences on the performance and the noise characteristics of th e various skew shapes of the stabilizer with the experimental rig which sim ulates the indoor unit of the split type room air-conditioners. Also a guid e is proposed to develop an optimal skew shape of the stabilizer, which dos e not significantly impede the aerodynamic performance and has a better noi se characteristics.