Abstract: To reduce aerodynamic noise during the operation of centrifugal fans and improve the flow adaptability and acoustic performance of the volute structure, proposes a three-dimensional curved surface volute structure based on non-uniform NURBS parametric modeling. Using a traditional volute as a reference, CFD and FW-H acoustic analogy methods are employed to conduct integrated numerical simulations of the flow field and acoustic field. The results show that the curved volute structure, by creating a “high in the middle, low on both sides” tangential flow channel, significantly improves the flow path from the impeller outlet to the volute tongue region, making the main flow more stable, reducing flow separation, and decreasing the peak turbulent kinetic energy by over 30%. Based on this, the pressure distribution on the volute wall becomes more uniform, the amplitude of unsteady fluctuations decreases, and the sound source intensity is significantly reduced. Spectral analysis shows that the sound pressure amplitude in the main frequency band below 1000 Hz decreases by approximately 4.2 dB(A), with an average reduction in total sound pressure of 3.6 dB(A), demonstrating excellent broadband noise reduction capabilities. The research results validate the comprehensive advantages of the curved volute structure in terms of aerodynamic and acoustic performance, providing theoretical basis and structural design methods for the development of high-efficiency, low-noise centrifugal fans.

Key words: Centrifugal fan, Curved volute, NURBS modeling, Aerodynamic noise, FW-H method