运用流场声场数值模拟的浴室排气离心风机多目标优化研究

Multi-objective Optimization Study of Bathroom Exhauster Centrifugal Fan Based on Numerical Simulation of Flow Field and Acoustic Field

针对某浴室排气离心风机效率降低、噪声大的问题,通过建立风机流量和噪声等多目标优化的方法,采用理想点法求解多目标优化函数,计算得到了风机设计参数的最优组合方案。在此基础上进行三维流动计算域建模,对离心风机内的流场和声场进行数值模拟计算,其中流场计算是对雷诺平均N-S方程进行数值求解,而声场计算是求解Lowson方程。计算结果表明改型后的风机内部气体流场较为均匀,出口处的回流现象得以消除。改型风机蜗壳蜗舌位置的湍流噪声源有明显的缩小。风机的总体性能指标有显著改善,最大流量增加12%,工作区间内全压效率提高3%~10%,进出口压差提高20 Pa左右,风机噪声下降1~2 dB。表明所采用的多目标优化和流场声场数值模拟相结合的方法对浴室排气离心风机优化设计是切实可行的。

Aiming at the problem that the reduced efficiency and pneumatic noise of centrifugal fan in a certain bathroom air-heater,a multiobjective optimization method was carried out and the flow rate and SWL of the centrifugal fan were taken as objective parameters.The multiobjective optimization was solved by ideal point method.A three-dimensional model was built based on the optimal combination of parameters,and the total pressure performance and noise of optimal centrifugal fan were obtained by numerical simulation and Lowson model.The simulation result showed that the gas flow field inside the modified fan is relatively uniform,and the backflow phenomenon at the outlet can be eliminated.The turbulence noise source at the volute tongue position of the modified fan is obviously reduced.The overall performance index of the fan has been significantly improved,with the maximum flow increased by 12%,the total pressure efficiency in the working range increased by 3%~10%,the inlet and outlet differential pressure increased by about 20 Pa,and the fan noise decreased by 1~2 dB.It shows that the method of multi-objective optimization combined with numerical simulation of flow field and sound field is feasible for the optimization design of bathroom exhaust centrifugal fan.