小流量工况下旋涡自吸泵流动降噪优化研究  

Flow-induced Noise of Self-priming Vortex Pump at Low-flow Rate

作　　者：王洋[1] 胡日新 汤海涛 汪群 余昊谦 贾静 

机构地区：[1]江苏大学流体机械工程技术研究中心,镇江212013

出　　处：《农业机械学报》2017年第11期188-195,共8页Transactions of the Chinese Society for Agricultural Machinery

基　　金：国家高技术研究发展计划(863计划)项目(2011AA100506);国家自然科学基金项目(51379091);江苏高校优势学科建设工程项目(PAPD)

摘　　要：为了研究旋涡自吸泵内部声场特性,减少旋涡自吸泵在小流量工况下运行时的噪声,采用CFD+Lighthill声类比理论对旋涡泵内部声场进行求解,并进行降噪优化。首先利用CFX软件提供的RNG k-ε模型,选取0.4Qd、0.8Qd及Qd3个流量点对旋涡泵进行非定常数值模拟,获得不同工况下旋涡自吸泵内部压力脉动情况。提取非定常计算所得的脉动力,导入声学软件ACTRAN中进行声场计算,得到不同工况下旋涡泵出口声压级的大小、泵体内部的声压分布以及泵内部主要噪声源分布。采用正弦调制叶片分布方式设计了调制角A为2°、4°、6°、8°的4种不同不等节距叶轮,通过对模型泵进行声场计算,最后选取降噪效果较好的调制角A=4°的不等节距叶轮进行3D打印,并对3D打印样品进行外特性和噪声试验验证。结果表明:旋涡泵内部流动诱导噪声与压力脉动密切相关,主要是由叶轮与泵体的动静干涉引起,其频率特性与压力脉动相似,2倍叶频时声压最大。流量越小,旋涡泵出口声压级越大,其噪声源主要分布在泵体流道及靠近流道出口隔舌处。调制角A=4°的不等节距叶片在小流量工况下对旋涡泵外特性性能影响不大,且能使小流量工况0.4Qd的噪声下降2 d B,设计工况噪声下降4 d B。In order to research the internal sound field characteristics and reduce the running noise of self-priming vortex pump at low-flow rate,the CFD and Lighthill sound analogy theory was adopted to solve the internal acoustic field and optimize the noise of self-priming vortex pump. Firstly,the pressure fluctuation of self-priming vortex at 0. 4 Qd,0. 8 Qdand Qdwere obtained from the unsteady simulation with the RNG k-ε turbulence model in CFX software. The datum of pressure fluctuation were extracted and input into the ACTRAN acoustics software,the SPL of the pump discharge,internal sound pressure distribution and main noise source in pumps at different flows were got by acoustic field calculation.Then,according to the laws of the Ewald frequency modulation,four different types of unequal spacing impellers were designed with modulation angle A of 2°,4°,6° and 8°. Finally,the acoustic field calculation of four different impellers was conducted,the impeller with unequal spacing and A value of 4°had lower noise,whose sample made by 3 D printing was chosen to conduct the performance and noise reduction test. The simulation results showed that the flow-induced noise of self-priming vortex pump was closely related to the pressure fluctuation which mainly caused by rotor-stator interaction,both of them had the same frequency characteristic,the maximum sound pressure appears at two times blade passing frequency. With the decrease of the flow rate,the SPL of the pump discharge was increased,the sound source of the self-priming vortex pump was mainly distributed in the channel and the tongue close to the pump discharge. The noise test results showed that the impeller sample with A value of 4°had little effect on the performance of the self-priming vortex pump and can reduce noise at low-flow rate,under the design point,noise can be decreased by 4 d B,and it can be decreased by 2 d B when low flow was 0. 4 Qd.

关 键 词：旋涡自吸泵 压力脉动 流动诱导噪声 不等节距叶片 数值模拟 

分 类 号：TH314[机械工程—机械制造及自动化]