基于密度修正的滤波器模型在轴流泵叶顶区空化数值模拟中的应用与验证

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振动与冲击 ›› 2016, Vol. 35 ›› Issue (14) : 41-46.

论文

石磊张德胜陈健潘大志耿琳琳

作者信息 +

Application and Verification of Density Correction Method Based Filter Based Method for Numerical Simulation of Cavitation in Tip Region of Axial-flow Pump

Shi Lei, Zhang Desheng, Chen Jian, Pan Dazhi, Geng Linlin

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文章历史 +

摘要

为了准确揭示轴流泵叶轮叶顶区的流场结构和空化形态，选用某一模型轴流泵进行数值模拟和空化可视化实验研究。研究结果表明，基于密度修正的滤波器湍流模型（Density Correction Method Based Filter Based Method, DCMFBM）可准确预测汽蚀余量NPSH值，预测最大误差比SST k-ω模型小3%；在小流量工况下，叶顶泄漏流和泄漏涡在叶顶区充分发展，随着流量的增大，泄漏流向叶顶中后部发展，且泄漏涡与叶片吸力面的夹角减小，泄漏流对相邻叶片压力面的影响减小；叶顶区轴向速度先减小后增大，泄漏流进入间隙时在压力面拐角处发生流动分离，在叶顶端面附近卷吸形成角涡，在离开间隙区前泄漏流又会重新附着在叶顶端面上；湍动能呈现先增大后减小的趋势，且峰值随着弦长系数的减小而增大。通过空化性能曲线和叶顶泄漏涡的空穴形态对比分析，验证了DCMFBM湍流模型的适用性。从高速摄影结果可见，随着空化的发展，叶轮叶顶区泄漏流空化、射流剪切层空化以及泄漏涡空化共同构成三角形云状空化结构，且叶片尾缘存在空泡脱落，揭示了叶顶泄漏涡不稳定的空化特性。

Abstract

A model axial flow pump was selected to deeply understand structure of flow field and cavitation morphology in tip region of impeller by numerical simulation and visualization experimental research. Research indicated that density correction method based Filter Based Method (DCMFBM) can accurately predict the cavitation number NPSHR value. The biggest prediction error of DCMFBM is smaller by 3% than SST k-ω turbulence model. Tip leakage flow and leakage vortex developed fully in tip region, the leakage flow developed towards the middle and back of rim with increase of flow rate, and the angle between leakage vortex and suction side decreased, the effect on the pressure side of the neighboring blade was also decreased with leakage flow. Axial velocity in tip region decreased first and then increased, separation occurring on the corner of pressure side while the leakage flow entered into the gap, forming angle vortex near wall of the tip, and leakage flow would re-attached to the wall of tip when left the gap. The turbulent kinetic energy increased at first and then decreased, and the peak decreased with increase of the chord length coefficient. The cavitation performance curve and the comparison of tip leakage vortex cavitation morphology verified the application of DCMFBM turbulence model. With the development of cavitation from high speed photography, tip leakage flow cavitation, jet shear layer cavitation and leakage vortex cavitation constituted the triangle structure, cavity fell off from the trailing edge, showing that the unsteady characteristic of tip leakage vortex cavitation.

导出引用

石磊张德胜陈健潘大志耿琳琳. 基于密度修正的滤波器模型在轴流泵叶顶区空化数值模拟中的应用与验证[J]. 振动与冲击, 2016, 35(14): 41-46

Shi Lei, Zhang Desheng, Chen Jian, Pan Dazhi, Geng Linlin. Application and Verification of Density Correction Method Based Filter Based Method for Numerical Simulation of Cavitation in Tip Region of Axial-flow Pump[J]. Journal of Vibration and Shock, 2016, 35(14): 41-46

参考文献

[1] 施卫东，张华，陈斌，等. 不同叶顶间隙下的轴流泵内部流场数值计算[J]. 排灌机械工程学报，2010, 28(5): 374-377.
Shi Wei-dong，Zhang Hua, Chen Bin, et al. Numerical simulation of internal flow field in axial-flow pump with different clearance sizes[J].Journal of Drainage and Irrigation Machinery and Engineering, 2010, 28(5): 374-377.
[2] 梁开洪, 张克危, 许丽. 轴流泵叶顶间隙流动的计算流体动力分析[J]. 华中科技大学学报: 自然科学版, 2004, 32(9): 36-38.
Liang Kai-hong，Zhang Ke-wei，Xu Li. Analysis of the flow through the blade tip clearances of axial pumps by CFD[J]. Journal of Huazhong University of Science and Technology (Natural Science Edition), 2004, 32(9): 36-38.
[3] 戴辰辰, 郭鹏程, 罗兴锜. 轴流泵端壁间隙流动特性的数值分析[J]. 流体机械, 2009, 37(6): 32-35.
Dai Chen-chen，Guo Peng-cheng, Luo Xing-qi. Numerical analysis of tip clearance flow characteristic in axial flow pump[J]. Fluid Machinery, 2009, 37(6): 32-35.
[4] Wu H, Miorini R L, Katz J. Measurements of the tip leakage vortex structures and turbulence in the meridional plane of an axial water-jet pump[J]. Experiments in fluids, 2011, 50(4): 989-1003.
[5] Wu H, Tan D, Miorini R L, et al. Three-dimensional flow structures and associated turbulence in the tip region of a waterjet pump rotor blade[J]. Experiments in fluids, 2011, 51(6): 1721-1737.
[6] Miorini R L, Wu H, Katz J. The internal structure of the tip leakage vortex within the rotor of an axial waterjet pump[J]. Journal of Turbomachinery, 2012, 134(3): 031018.
[7] 张德胜, 陈健, 施卫东, 等. 轴流泵叶顶泄漏涡空化的数值模拟与可视化实验研究[J]. 工程力学, 2014, 31(9): 225-231.
Zhang De-sheng, Chen Jian, Shi Wei-dong, et al. Numerical simulation and visualization study on tip leakage vortex cavitation in an axial-flow pump[J]. Engineering Mechanics, 2014, 31(9): 225-231.
[8] Wu H, Soranna F, Michael T, et al. Cavitation in the tip region of the rotor blades within a waterjet pump[C]//ASME 2008 Fluids Engineering Division Summer Meeting collocated with the Heat Transfer, Energy Sustainability, and 3rd Energy Nanotechnology Conferences. American Society of Mechanical Engineers, 2008: 193-202.
[9] 张德胜, 吴苏青, 施卫东, 等. 轴流泵小流量工况条件下叶顶泄漏空化特性[J]. 农业工程学报, 2013, 29(22): 68-75.
Zhang De-sheng, Wu Su-qing, Shi Wei-dong, et al. Characteristics of tip leakage vortex cavitation in axial flow pump at small flow rate condition[J]. Transactions of the Chinese Society of Agricultural Engineering, 2013, 29(22): 68-75.
[10] 黎耀军, 沈金峰, 刘竹青, 等. 轴流泵轮缘间隙非定常流动的大涡模拟[J]. 农业机械学报, 2013, 44(z1): 113-118.
Li Yao-jun, Shen Jin-feng, Liu Zhu-qing, et al. Large eddy simulation of unsteady flow in tip region of axial-flow pump[J]. Transactions of the Chinese Society for Agricultural Machinery, 2013, 44(z1): 113-118.
[11] 黎耀军, 沈金峰, 严海军, 等. 叶顶间隙对轴流泵轮缘泄漏流动影响的大涡模拟[J]. 水利学报, 2014, 45(2): 235-242.
Li Yao-jun, Shen Jin-feng, Liu Zhu-qing, et al. Investigation of the effects of tip-gap size on the tip-leakage flow in an axial-flow pump using LES[J]. Journal of Hydraulic Engineering, 2014, 45(2): 235-242.
[12] Zhang De-sheng, Shi Wei-dong, van Esch B P M B, et al. Numerical and experimental investigation of tip leakage vortex trajectory and dynamics in an axial flow pump[J]. Computers & Fluids, 2015, 112: 61-71.
[13] Zhang De-sheng, Pan Da-zhi, Shi Wei-dong, et al. Study on tip leakage vortex in an axial flow pump based on modified shear stress transport k-ω turbulence model[J]. Thermal Science, 2013, 17(5): 1551-1555.
[14] 施卫东, 吴苏青, 张德胜, 等. 叶片数对高比转数轴流泵空化特性的影响[J]. 农业机械学报, 2013, 44(11): 72-77.
Shi Wei-dong, Wu Su-qing, Zhang De-sheng, et al. Effects of number of blades on cavitation of high specific speed axial flow pump[J]. Transactions of the Chinese Society for Agricultural Machinery, 2013, 44(11): 72-77.
[15] 施卫东, 吴苏青, 张德胜, 等. 叶顶形状对轴流泵空化性能的影响[J]. 农业机械学报, 2014, 45(9): 101-106.
Shi Wei-dong, Wu Su-qing, Zhang De-sheng, et al. Effects of blade tip shape on cavitating flow in axial flow pumps[J]. Transactions of the Chinese Society for Agricultural Machinery, 2014, 45(9): 101-106.
[16] Coutier-Delgosha O, Reboud J L, Fortes-Patella R. Evaluation of the turbulence model influence on the numerical simulations of unsteady cavitation[J]. Journal of Fluids Engineering, 2003, 125(1): 38-45.
[17] Knapp R T, Daily J T, Hammit F G. Cavitation[M]. New York, 1970.
[18] 张博，王国玉，张淑丽，等. 修正的RNG k-ε 模型在云状空化流动计算中的应用评价[J]. 北京理工大学学报, 2008, 28(12): 1065-1069.
Zhang Bo, Wang Guo-yu, Zhang Shu-li, et al. Evaluation of a modified RNG k-ε model for computations of cloud cavitating flows. Transactions of Beijing Institute of Technology, 2008, 28(12): 1065-1069.
[19] Wu J, Wang G, Shyy W. Time-dependent turbulent cavitating flow computations with interfacial transport and filter-based models[J]. International Journal for Numerical Methods in Fluids, 2005, 49(7): 739-761.