叶片出口边侧斜对船用离心泵外辐射噪声的影响

Effect of inclined trailing edge of blade on exterior radiation noise of marine centrifugal pump

以125CLLA-13型船用离心泵为研究对象,分析叶片出口边侧斜对船用离心泵外辐射噪声的影响.首先对出口边非侧斜和侧斜2种叶轮模型泵进行了全流场瞬态数值计算,提取蜗壳及泄漏流道壁面脉动激励作为载荷,对原模型泵进行基于模态响应的振动计算,并试验验证了振动噪声数值预测的可行性.进一步以提取的载荷对2种叶轮模型泵进行了基于声振耦合的外辐射噪声计算,结果表明:相同工况下2种叶片出口方式模型泵声功率频谱变化趋势基本一致,侧斜出口模型泵声功率级明显低于非侧斜出口模型泵声功率级LW,声功率级均在叶频(BPF)处最大,且叶频处声功率级在设计工况下最小,在小流量工况下最大;离心泵外辐射噪声分布具有一定偶极性和指向性,各工况下侧斜出口模型泵指向性声压整体较非侧斜模型泵有所减小,设计工况下指向性声压最小,小流量工况下指向性声压最大,从降噪角度考虑,侧斜出口方式优于非侧斜出口方式.该研究可为船用离心泵减振降噪设计提供参考.

In order to analyze the effect of inclined trailing edge of blade on the exterior radiation noise of marine centrifugal pump,a 125CLLA- 13 type marine centrifugal pump was chosen as the research object. The blade with inclined trailing edge and the blade without inclined trailing edge were used in the unsteady numerical simulation of the pump＇ s whole flow passage respectively. Then the pressure fluctuation of the wall of volute and leakage flow was obtained as the vector load. By loading the vector as the vibration source,the simulation of vibration based on modal response were conducted,and the vibration experiment of the pump without inclined trailing edge was done to verify the feasibility of simulation of noise of vibration. The further work was to simulate and analyze the exterior radiation noise of the model pump with different blade styles based on the acoustic- vibro coupling method. The results show that the changing trend of the sound power spectrum of the two blade styles is consistent at thesame condition,but the LWof the blade with inclined trailing edge is obviously less than the other one.The maximum LWis at the BPF,and the design condition has the minimum value of LWat the BPF,the small flow rate condition has the maximum value of LWat the BPF. The exterior radiation noise of centrifugal pump has certain dipolarity and directivity,and the inclinded trailing edge of blade can reduced the sound pressure at the directivity field point. The minimum of sound pressure is at the design condition,and the maximum is at the small flow rate condition. Considering the terms of vibration and noise reduction,the blade with inclined trailing edge is superior to the blade without inclined trailing edge.The research results are useful for the vibration and noise reduction design of the marine centrifugal pump.