Development of low-noise centrifugal fans for a refrigerator using inclined S-shaped trailing edge

Low-noise centrifugal fans are developed by modifying the linear trailing edge lines of the fan blades into inclined S-shaped lines. The noise reductions achieved by using the inclined S-shaped trailing edges in the existing fans are confirmed by comparing the predicted BPF noise components of the developed fans with those of the existing fan. In addition, the turbulent kinetic energy of the fluid for the inclined S-shaped fans is predicted to be less than that for the existing fan. Finally, experiments using four prototype fans show that the levels of broadband noise from the newly developed fans are less than those of noise from existing fans. An additional experiment performed by using a selected low-noise fan installed in a household refrigerator show that the overall noise from the new fan is reduced by approximately 2.2 dB in comparison with that from the existing fan in the refrigerator.