上下并联轴流风机室外机气动声学预测模型

本文基于CFD模拟方法,分析了空调器室外机上下并联轴流风机系统噪声源分布,建立了室外机气动声学预测方法.研究发现,上下并联轴流风机系统由宽频和离散频率噪声组成,宽频噪声是影响室外机噪声总声压级的重要因素.涡声分析表明,涡脱落噪声是宽频噪声的主要影响因素.基于CFD的叶片尾缘涡脱落噪声预测方法计算得到宽频声压误差为2 dB,考虑离散频率影响时,室外机A计权总声压级预测误差小于2 dBA.基于CFD的点源时域预测模型,捕捉到了上下并联轴流风机系统的离散频率噪声峰值,且在上下叶轮前二阶谐波处预测值与实验值吻合较好.

AEROACOUSTIC PREDICTION OF COLLATERAL AXIAL FAN INSIDE OUTDOOR UNITS

Aerodynamic noise source of collateral axial fan inside outdoor units is studied and aeroacoustic prediction of outdoor units is built based on CFD simulation.It is shown that noise spectrum of outdoor units is composed of broadband and discrete frequency noise,and broadband noise is a major factor at total sound pressure level (SPL)of outdoor units.Vortex shedding noise is a major source of broadband noise by analysis of vortex-sound theory.Broadband noise is predicted by vortex shedding noise model based on CFD simulation with an error of 2 dB.When discrete frequency is considered.the error of A-weighed total SPL of units is less than 2 dBA.The frequency of discrete noise of units is captured by point-source prediction in time domain based on CFD simulation.and prediction at first two harmonics of coilateral axial fan is consistent with experimental noise.