小流量工况下旋涡自吸泵流动降噪优化研究

发布时间：2018-07-23 13:57

【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。
[Abstract]:In order to study the internal sound field characteristics of vortex self-priming pump and reduce the noise of vortex self-priming pump operating under small flow conditions, the sound field of vortex pump is solved by CFD Lighthill acoustic analogy theory, and the noise reduction optimization is carried out. Firstly, using the RNG k- 蔚 model provided by CFX software, the unsteady numerical simulation of the vortex pump is carried out with 0.4Qdl0.8Qd and Qd3 flow points, and the pressure fluctuation inside the vortex self-priming pump under different working conditions is obtained. The pulse force is extracted from the unsteady calculation, and the acoustic field is calculated in the acoustic software ACTRAN. The magnitude of the sound pressure level at the outlet of the vortex pump, the distribution of the sound pressure inside the pump body and the distribution of the main noise sources inside the pump are obtained under different working conditions. Four different pitch impellers with modulation angle A of 2 掳and 4 掳/ 6 掳/ 8 掳are designed by using sinusoidal modulation vane distribution mode. By calculating the sound field of the model pump, the impeller with different pitch with better noise reduction effect is selected for 3D printing. The external characteristics and noise of 3D printed samples were verified. The results show that the noise induced by flow in the vortex pump is closely related to the pressure pulsation, which is mainly caused by the dynamic and static interference between the impeller and the pump body, and its frequency characteristic is similar to that of the pressure pulsation. The smaller the flow rate, the greater the sound pressure level at the outlet of the vortex pump. The noise source is mainly distributed in the pump body channel and near the outlet tongue of the pump. The variable pitch blade with modulation angle of 4 掳has little effect on the external performance of vortex pump under the condition of small flow rate, and can reduce the noise of 0.4Qd and design condition by 2 dB and 4 dB respectively.
【作者单位】：江苏大学流体机械工程技术研究中心;
【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)
【分类号】：TH317

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