中比转速离心泵小流量工况下压力脉动特性
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摘要
采用Navier-Stokes方程和RNG k-ε湍流模型,对不同流量工况下离心泵内部非定常流动进行了数值计算,计算得到的离心泵外特性与试验结果吻合较好。数值模拟结果表明,不同流量工况下叶轮内压力脉动具有明显的周期性变化,压力脉动强度随着流量的减小而增强,叶片压力面脉动强度更加剧烈,叶轮旋转频率始终占主导作用。由叶轮进口至出口,叶片压力面和吸力面压力脉动最大幅值均渐渐增大。相同监测点的压力脉动最大幅值在30%设计流量工况时最大,约为设计流量工况下3~4倍。随时间叶轮流道内存有旋涡的产生、发展、脱落的周期性变化过程,这是造成离心泵运行效率低、压力脉动副值增大、脉动波形紊乱的主因。
The unsteady flows for different operating conditions in centrifugal pump are numerically investigated by using Navier-Stokes equations and RNG k-ε turbulence model. The calculation results of external characteristic are in good agreement with experimental data. The pressure fluctuation in impeller has obvious periodic property under different flow conditions,the intensity of pressure fluctuation increases with the decrease of flow rate. The influence of low flow condition on impeller suction side is the most obvious. The dominant frequencies of pressure fluctuation on blade surface are the impeller rotating frequency.The amplitudes of pressure fluctuation increase gradually from impeller inlet to outlet. The maximum amplitude of pressure fluctuation appears in the condition of 30% design flow and the value is about 3-4 times of that under design flow condition.The vortex in impeller is also periodically generated,developed and shed,which is the main cause of low operating efficiency,large pressure fluctuation and disturbed fluctuation waveform of centrifugal pump.
The unsteady flows for different operating conditions in centrifugal pump are numerically investigated by using Navier-Stokes equations and RNG k-ε turbulence model. The calculation results of external characteristic are in good agreement with experimental data. The pressure fluctuation in impeller has obvious periodic property under different flow conditions,the intensity of pressure fluctuation increases with the decrease of flow rate. The influence of low flow condition on impeller suction side is the most obvious. The dominant frequencies of pressure fluctuation on blade surface are the impeller rotating frequency.The amplitudes of pressure fluctuation increase gradually from impeller inlet to outlet. The maximum amplitude of pressure fluctuation appears in the condition of 30% design flow and the value is about 3-4 times of that under design flow condition.The vortex in impeller is also periodically generated,developed and shed,which is the main cause of low operating efficiency,large pressure fluctuation and disturbed fluctuation waveform of centrifugal pump.
引文
[1]周佩剑,王福军,姚志峰.叶片数对离心泵叶轮失速特性影响研究[J].机械工程学报,2016,52(10):207-212.
[2]潘中永,李俊杰,李晓俊,等.斜流泵不稳定特性及旋转失速研究[J].农业机械学报,2012,43(5):64-68.
[3]WANG H,TSUKAMOTO H.Experimental and numerical study of unsteady flow in a diffuser pump at off-design conditions[J].Journal of Fluids Engineering,2003,125(5):767-778.
[4]周佩剑,王福军,姚志峰.旋转失速条件下离心泵隔舌区动静干涉效应[J].农业工程学报,2015,31(7):85-90.
[5]KRAUSE N,PAP E,THEVENIN D.Part-load flow instabilities in a radial pump measured with TR-PIV[C]∥Proceeding of the 4th WSEAS International Conference on Fluid Mechanics and Aerodynamics,Greece,2006:319-324.
[6]李景悦,罗丽.核主泵压水室非定常流动特性分析[J].水力发电,2016,42(6):53-56.
[7]谭磊,王玉川,曹树良,等.离心泵蜗舌区非定常流动特性[J].北京理工大学学报,2014,34(7):670-675.
[8]王玉川,谭磊,曹树良,等.离心泵叶轮区瞬态流动及压力脉动特性[J].机械工程学报,2014,50(10):163-169.
[9]瞿丽霞,王福军,丛国辉,等.双吸离心泵叶片区压力脉动特性分析[J].农业机械学报,2011,42(9):79-84.
[10]王业芳,袁寿其,张金凤,等.低比转数离心泵小流量工况下的压力脉动特性[J].排灌机械工程学报,2016,34(5):399-405.
[11]邱勇,季燕羽,杨洪镔,等.低比转数离心泵叶轮内流动分离的PIV实验研究[J].中国农村水利水电,2016(10):182-185.
[12]孟根其其格,谭磊,曹树良,等.离心泵蜗壳内非定常流动特性的数值模拟及分析[J].机械工程学报,2015,51(22):183-190.
[13]谭磊.离心泵叶轮的优化设计理论及方法研究[D].北京:清华大学,2011.
[2]潘中永,李俊杰,李晓俊,等.斜流泵不稳定特性及旋转失速研究[J].农业机械学报,2012,43(5):64-68.
[3]WANG H,TSUKAMOTO H.Experimental and numerical study of unsteady flow in a diffuser pump at off-design conditions[J].Journal of Fluids Engineering,2003,125(5):767-778.
[4]周佩剑,王福军,姚志峰.旋转失速条件下离心泵隔舌区动静干涉效应[J].农业工程学报,2015,31(7):85-90.
[5]KRAUSE N,PAP E,THEVENIN D.Part-load flow instabilities in a radial pump measured with TR-PIV[C]∥Proceeding of the 4th WSEAS International Conference on Fluid Mechanics and Aerodynamics,Greece,2006:319-324.
[6]李景悦,罗丽.核主泵压水室非定常流动特性分析[J].水力发电,2016,42(6):53-56.
[7]谭磊,王玉川,曹树良,等.离心泵蜗舌区非定常流动特性[J].北京理工大学学报,2014,34(7):670-675.
[8]王玉川,谭磊,曹树良,等.离心泵叶轮区瞬态流动及压力脉动特性[J].机械工程学报,2014,50(10):163-169.
[9]瞿丽霞,王福军,丛国辉,等.双吸离心泵叶片区压力脉动特性分析[J].农业机械学报,2011,42(9):79-84.
[10]王业芳,袁寿其,张金凤,等.低比转数离心泵小流量工况下的压力脉动特性[J].排灌机械工程学报,2016,34(5):399-405.
[11]邱勇,季燕羽,杨洪镔,等.低比转数离心泵叶轮内流动分离的PIV实验研究[J].中国农村水利水电,2016(10):182-185.
[12]孟根其其格,谭磊,曹树良,等.离心泵蜗壳内非定常流动特性的数值模拟及分析[J].机械工程学报,2015,51(22):183-190.
[13]谭磊.离心泵叶轮的优化设计理论及方法研究[D].北京:清华大学,2011.