单叶片离心泵蜗壳内二次流的非定常特性研究  

Investigation on Unsteady Characteristics of Secondary Flow in Volute of Single-blade Centrifugal Pump

作　　者：周佩剑[1] 刘涛 牟介刚[1] 谷云庆[1] 吴登昊[1] 任芸 

机构地区：[1]浙江工业大学机械工程学院,杭州310014

出　　处：《农业机械学报》2018年第1期130-136,共7页Transactions of the Chinese Society for Agricultural Machinery

基　　金：国家自然科学基金项目(51709234;51609212);浙江省自然科学基金项目(LQ17E090005);浙江省公益技术应用研究项目(2017C31025)

摘　　要：单叶片离心泵蜗壳内易形成二次流旋涡,容易诱发高幅值的压力脉动,严重时还会降低水泵运行的安全稳定性。基于SST k-ω模型,对单叶片离心泵在典型工况下的非定常流动进行数值模拟,得到了其内部流场和压力脉动特性。结果表明,数值计算结果与实验结果基本一致。对压力脉动特性进行分析,发现在不同流量工况下,泵内流场均表现出明显的周期性变化的压力脉动特性,蜗壳第一断面压力脉动强度最低,第二断面压力脉动强度最高。压力脉动的主频均是叶片通过频率,随着流量的增加主频幅值呈现减小的趋势。进一步对单叶片离心泵的蜗壳内二次流的非定常特性进行分析,发现不同流量工况下,蜗壳内均出现二次流旋涡,并随着叶轮旋转也呈现出周期性变化。蜗壳内的横向速度在额定流量下较小,在非额定流量下显著增大。该研究可为单叶片离心泵机组运行稳定性提供一定参考。The impeller of a single-blade centrifugal pump has an asymmetric characteristic,and the secondary flow vortex is easy to form in the spiral volute,which will induce high pressure fluctuation and affect the safety and stability of the pump system. In order to reveal the unsteady characteristics of the secondary flow inside the spiral volute,a single-blade centrifugal pump was chosen as the research object to investigate by numerical simulation. The SST k-ω model was applied to simulate the three-dimensional unsteady viscous incompressible flow in the centrifugal pump. The predictions of the numerical model were compared with experimental results,and it showed good agreement between the simulation and experiment results. The pressure fluctuation characteristics of single-blade centrifugal pump under multiple conditions were studied. The results showed that the flow field in the pump presented obvious pressure fluctuation characteristics under different flow conditions. The pressure fluctuation intensity of the first section of the volute was the lowest,and the pressure fluctuation intensity of the second section was the highest. The dominant frequency of pressure fluctuations was the blade pass frequency. With the increase of the flow rate,the amplitude of the dominant frequency was decreased. Then the secondary flow inside the spiral volute of the single-blade centrifugal pump was further analyzed. Under the three flow rate conditions,the secondary flow vortex appeared in the volute,the shape of which showed obvious periodicity. The magnitude of cross flow velocity was decreased firstly and then increased with the increase of the flow rate. It was relatively small under the design flow condition while it was increased significantly under off-design condition. The research can provide theoretical basis for the safe and stable operation of single-blade centrifugal pumps.

关 键 词：单叶片离心泵 蜗壳 压力脉动 二次流 非定常数值模拟 

分 类 号：TH311[机械工程—机械制造及自动化]