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应用旋转模态理论和CFD方法研究贯流叶轮的离散噪声特性,并分析贯流风机远场噪声主要呈现宽频的原因.设计了三种不同的蜗壳匹配方案,以控制贯流风机内主要的涡结构。通过采用CFD方法计算不同方案中贯流风机内部涡流动结构主要位置,确定出贯流叶轮上下游发生干涉的叶片数。根据模态分析理论,计算了不同蜗壳及蜗舌匹配方案中贯流叶轮的截止率。计算结果表明,由于叶轮内主流速度较低,使得贯流风机的离散噪声不明显。
The rotational mode theory and the CFD method are used to study the discrete noise characteristics of the tubular impeller and to analyze the reason why the far-field noise of the tubular fan mainly presents wide frequency. Three different schemes of volute matching are designed to control the main Vortex structure. By using CFD method to calculate the main position of the vortex flow structure inside the cross flow fan in different schemes, the number of blades interfering with the upstream and downstream of the cross flow impeller is determined. According to the modal analysis theory, the cut-off rates of the turbine impellers in different volute and worm tongue matching schemes were calculated. The calculation results show that due to the low main flow velocity in the impeller, the discrete noise of the cross flow fan is not obvious.