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多翼离心风机并联系统有限的出口面积使风机性能受到制约,为提高并联运行状态下的风机性能,需对蜗壳的出口结构进行相应的优化.本文引入系数ε表征蜗壳出口段流道的收缩程度,详细分析了该收缩度ε对风机性能的影响,并根据不同方案的计算结果提出了一种针对并联系统风机的等面积优化法.基于该方法对原风机蜗壳结构进行了局部改型,模拟及试验结果表明:等面积优化法消除了流道中出口面积受限造成的压力损失,蜗舌附近流动得到明显改善,气动性能也得到较大提升.“,”The fixed discharge area of multi-blade centrifugal fan parallel system restricts its'aerodynamic performance.In order to improve the performance of fans operating in such a parallel system,a structure optimization should be implemented at the outlet zone of volute.In this paper,coefficient ε was used to characterization the degree of flow channel's contraction at the outlet,its' effects on the performance of fans had been studied detailedly.Ahomalographic optimized method was proposed by comparing the calculated aerodynamic performances of modified cases with different contraction coefficient.The structure of volute outlet zone was modified based on this method.The numerical and experimental results showed that homalographic optimization eliminated the pressure loss caused by the limited discharge area,the flow field near the volute tongue was significantly improved and the performance of parallel system has been increased obviously.