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International Standard Serial Number:
ISSN 1001-4551
Sponsor:
Zhejiang University;
Zhejiang Machinery and Electrical Group
Edited by:
Editorial of Journal of Mechanical & Electrical Engineering
Chief Editor:
ZHAO Qun
Vice Chief Editor:
TANG ren-zhong,
LUO Xiang-yang
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Abstract: Aiming at controlling the noise radiated from an large axial-flow fan, the numerical study was conducted to study the influence of conical diffuser angle design on the aerodynamic noise of the axial flow fan. Firstly, the flow and acoustic characteristics of an evaporative cooling axial fan were investigated through the experiments conducted in a wind chamber and anechoic chamber. Moreover, the flow field was simulated using the large eddy simulation(LES)method, and the aerodynamic noise was predicted using acoustic analogy based on the Ffowcs Williams-Hawkings (FW-H) equation. Then simulation results were successfully validated compared to the performance experimental data of the axial flow fan. Finally, the impacts of three diffuser angles (8°,9°,10°) on the static recovery coefficient and the noise spectrum were numerically analyzed with Fluent. The results show that three conical diffusers could made a decrease in the aerodynamic noise. The research results show that: (1) the diffusers with three different expansion angles can reduce the aerodynamic noise of the fan; (2) when the diffusion angle was 9°, the vortex at the fan outlet was significantly reduced, the static pressure recovery coefficient was 0.654, and the Compared with no diffuser, the noise reduction in the most sensitive area of the human ear from 2000Hz to 4000Hz was the largest, which can be reduced by 4.7%. This study can provide a reference for reducing noise reduction of axial fans for largescale evaporative air conditioners.
Key words: ventilating fan; static recovery coefficient; aerodynamic noise; noise spectrum; fan performance; numerical simulation