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| DMD analysis on the unsteady flow in a centrifugal pump impeller |
| CHEN Xuebing1，ZHANG Renhui1,2，JIANG Lijie1，GUO Guangqiang1 |
1. School of Energy and Power Engineering, Lanzhou University of Technology, Lanzhou 730050, China;
2. Key Laboratory of Fluid Machinery and Systems, Gansu Province, Lanzhou University of Technology, Lanzhou 730050, China |
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Abstract In order to accurately analyze the complex unsteady flow characteristics in centrifugal pump impeller, the large eddy simulation (LES) of unsteady flow in the pump was carried out to obtain the flow field distribution within the impeller. Dynamic modal decomposition (DMD) was performed on the transient relative velocity field of impeller under the designed flow rate condition and small flow rate condition, and the first four modes and corresponding frequency information that can reflect the complex flow characteristics were obtained. The analysis results show that DMD method can effectively identify the pulsation frequencies of complex flow in impeller and extract the corresponding flow field structures. The complex flow field characteristics in impeller can be divided into basic mode, high order dynamic mode reflecting flow separation and unsteady vortex structure within the impeller channel. The basic mode can reflect the steady-state flow field characteristics caused by flow passage, including the high-speed jet region and low-speed wake region at the impeller outlet and flow separation region on the blade suction side. The second to fourth dynamic modes of the relative velocity under the designed flow rate condition reflect the flow field characteristics of the flow separation and unsteady vortex structure shedding on the blade suction side caused by the interference of the volute. The dynamic modes of the relative velocity field under small flow rate condition represent the flow field characteristics such as flow separation and stall in the channel due to impeller rotation and volute interference. The DMD method can effectively approximate the important flow field structures in the impeller, and clearly analyze the complex transient flow characteristics in centrifugal pump impeller.
Key words: centrifugal pump; unsteady flow; large eddy simulation(LES); flow separation; dynamic modal decomposition(DMD)
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Received: 10 November 2021
Published: 28 July 2022
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[1] WU Chengshuo, ZHANG Wenqi, WU Peng, et al. Effects of blade pressure side modification on unsteady pressure pulsation and flow structures in a centrifugal pump[J]. Journal of Fluids Engineering, 2021, 143(11): 111208.
[2] 裴吉，王文杰，袁寿其，等. 低比转数离心泵内部非定常流动特性数值预测[J]. 农业机械学报，2014, 45(1): 79-83,88.
PEI Ji, WANG Wenjie, YUAN Shouqi, et al. Numerical prediction of inner flow unsteadiness in a low-specific speed centrifugal pump[J]. Transactions of the Chinese Society for Agricultural Machinery, 2014, 45(1): 79-83,88.(in Chinese)
[3] KELLER J, BLANCO E, BARRIO R, et al. PIV measurements of the unsteady flow structures in a volute centrifugal pump at a high flow rate[J]. Experiments in Fluids, 2014, 55: 1820.
[4] 朱相源，赖芬，谢昌成，等. 离心泵动静干涉的试验及数值研究[J]. 哈尔滨工程大学学报，2020, 41(8): 1176-1183.
ZHU Xiangyuan, LAI Fen, XIE Changcheng, et al. Experimental and numerical studies on the rotor-stator interaction of a centrifugal pump[J]. Journal of Harbin Engineering University, 2020, 41(8): 1176-1183.(in Chinese)
[5] 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.
MENG Genqiqige, TAN Lei, CAO Shuliang, et al. Numerical simulation and analysis of unsteady flow characteristics in centrifugal pump volute[J]. Journal of Mechanical Engineering, 2015, 51(22): 183-190.(in Chinese)
[6] POSA A, LIPPOLIS A. Effect of working conditions and diffuser setting angle on pressure fluctuations within a centrifugal pump[J]. International Journal of Heat and Fluid Flow, 2019, 75: 44-60.
[7] 王文杰，邓起凡，裴吉，等. 双吸离心泵压力脉动特性数值模拟及试验研究[J]. 振动与冲击，2020，39(19): 107-113.
WANG Wenjie, DENG Qifan, PEI Ji, et al. Numerical simulation and tests for pressure fluctuation characteristics in a double-suction centrifugal pump[J]. Journal of Vibration and Shock, 2020, 39(19): 107-113.(in Chinese)
[8] ZHOU P J, WANG F J, YANG M. Internal flow numerical simulation of double-suction centrifugal pump using DES model[J]. IOP Conference Series: Earth and Environmental Science, 2012, 15: 032051.
[9] 代翠，董亮，刘厚林，等. 离心泵叶轮全流道非定常数值计算及粒子图像测速试验[J]. 农业工程学报，2013, 29(2): 66-72.
DAI Cui, DONG Liang, LIU Houlin, et al. Unsteady constant value calculation and particle image velocimetry experiment in full passages of centrifugal pump impeller[J]. Transactions of the Chinese Society of Agricultural Engineering (Transactions of the CSAE), 2013, 29(2): 66-72.(in Chinese)
[10] 司乔瑞，袁寿其，袁建平. 叶轮隔舌间隙对离心泵性能和流动噪声影响的试验研究[J]. 振动与冲击，2016，35(03): 164-168.
SI Qiaorui, YUAN Shouqi, YUAN Jianping. Experimental study on the influence of impeller-tongue gap on the performance and flow-induced noise characteristics of centrifugal pumps[J]. Journal of Vibration and Shock, 2016, 35(03): 164-168.(in Chinese)
[11] 高波，王兴宁，李忠，等. 离心泵非设计工况内部流动特性研究[J]. 工程热物理学报，2015, 36(12): 2624-2628.
GAO Bo, WANG Xingning, LI Zhong, et al. Study on the internal flow characteristics of a centrifugal pump under off-design conditions[J]. Journal of Engineering Thermophysics, 2015, 36(12): 2624-2628.(in Chinese)
[12] PEDERSEN N, LARSEN P S, JACOBSEN C B. Flow in a centrifugal pump impeller at design and off-design conditions-part I: particle image velocimetry (PIV) and laser doppler velocimetry (LDV) measurements[J]. Journal of Fluids Engineering, 2003, 125(1): 61-72.
[13] BYSKOV R K, JACOBSEN C B, PEDERSEN N. Flow in a centrifugal pump impeller at design and off-design conditions-part II: large eddy simulations[J]. Journal of Fluids Engineering, 2003, 125(1): 73-83.
[14] ZHANG Ning, LIU Xiaokai, GAO Bo, et al. DDES analysis of the unsteady wake flow and its evolution of a centrifugal pump[J]. Renewable Energy, 2019, 141: 570-582.
[15] 郭荣，李仁年，张人会，等. 射流式离心泵内场流体动力噪声特性分析[J]. 农业机械学报，2018, 49(4): 156-164.
GUO Rong, LI Rennian, ZHANG Renhui, et al. Characteristic analysis of interior hydrodynamic noise in jetting centrifugal pump[J]. Transactions of the Chinese Society for Agricultural Machinery, 2018, 49(4): 156-164.(in Chinese)
[16] 寇家庆，张伟伟. 动力学模态分解及其在流体力学中的应用[J]. 空气动力学学报，2018, 36(2): 163-179.
KOU Jiaqing, ZHANG Weiwei. Dynamic mode decomposition and its applications in fluid dynamics[J]. Acta Aerodynamica Sinica, 2018, 36(2): 163-179.(in Chinese)
[17] LIU Ming, TAN Lei, CAO Shuliang. Dynamic mode decomposition of gas-liquid flow in a rotodynamic multiphase pump[J]. Renewable Energy, 2019, 139: 1159-1175.
[18] 韩亚东，谭磊. 文丘里管空化流动的试验研究及动力学模态分解[J]. 机械工程学报，2019, 55(18): 173-179.
HAN Yadong, TAN Lei. Experiment and dynamic mode decomposition of cavitating flow in venturi[J]. Journal of Mechanical Engineering, 2019, 55(18): 173-179.(in Chinese)
[19] LIU Yingzheng, ZHANG Qingshan. Dynamic mode decomposition of separated flow over a finite blunt plate: time-resolved particle image velocimetry measurements[J]. Experiments in Fluids, 2015, 56: 148.
[20] KOU Jiaqing, ZHANG Weiwei. An improved criterion to select dominant modes from dynamic mode decomposition[J]. European Journal of Mechanics B/Fluids, 2017, 62: 109-129.
[21] SCHMID P J. Dynamic mode decomposition of numerical and experimental data[J]. Journal of Fluid Mechanics, 2010, 656: 5-28.
[22] SCHMID P J. Application of the dynamic mode decomposition to experimental data[J]. Experiments in Fluids, 2011, 50: 1123-1130.
[23] ROWLEY C W, MEZIĆ I, BAGHERI S, et al. Spectral analysis of nonlinear flows[J]. Journal of Fluid Mechanics, 2009, 641: 115-127.
[24] 洪树立，黄国平，陆惟煜，等. 采用DMD方法研究叶栅不同攻角的拟序结构[J]. 航空动力学报，2018, 33(9): 2150-2160.
HONG Shuli, HUANG Guoping, LU Weiyu, et al. Coherent structures of cascade under different attack angles with DMD method[J]. Journal of Aerospace Power, 2018, 33(9): 2150-2160.(in Chinese)
[25] 张人会，王少华，OSMAN JUMA S A. 螺旋轴流式油气混输泵导叶内非定常流动DMD分析[J]. 农业机械学报，2020, 51(9): 118-126.
ZHANG Renhui, WANG Shaohua, OSMAN JUMA S A. Transient gas-liquid flow in helical axial pump diffuser and its DMD analysis[J]. Transactions of the Chinese Society for Agricultural Machinery, 2020, 51(9): 118-126.(in Chinese)
[26] 吴亚东，李涛，赖生智. POD和DMD方法分析不同间隙压气机旋转不稳定性特性[J]. 航空动力学报，2019, 34(9): 2018-2026.
WU Yadong, LI Tao, LAI Shengzhi, et al. Analysis of rotating instability characteristics in compressor with different tipclearances by POD and DMD methods[J]. Journal of Aerospace Power, 2019, 34(9): 2018-2026.(in Chinese)
[27] RUHE A. Rational Krylov sequence methods for eigenvalue computation[J]. Linear Algebra and its Applications, 1984, 58: 391-405. |
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