非均匀进流下喷水推进泵的内流特性和载荷分布
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摘要
为描述实际航行时喷水推进泵非均匀进流的结构特点,解释喷水推进泵实际性能与试验测试值之间的差异,采用雷诺时均模型和RNG k-ε湍流模型数值计算非均匀进流下喷水推进泵的外特性,对比后获得了非均匀进流下喷水推进泵外特性降幅曲线,其中扬程和效率的最大降幅均为30%。进一步求解内流场,结果表明:非均匀进流中的低能螺旋流受旋转叶片的诱导,在轮缘处演变为以周向分离涡为主的进口畸变流,流道堵塞,受排挤的工作流体因液流角过大在叶片轮毂处发生流动分离,最终卷吸形成螺旋分离涡;此分离涡沿径向扰动叶片前缘流场,诱发回流和二次流,加剧了水力损失。同时,分离涡破坏绕翼环流,改变叶片静压分布,导致叶片载荷由前载型转变为中载型,削弱了叶片做功能力。因此,内流特性和载荷突变共同证实了非均匀进流是喷水推进泵性能下降的主要原因。
Insufficient understanding of large deviations between experiment performance and actual performance is a major problem encountered in the water-jet pump application. This study describes the non-uniform flow structure from the intake duct,and explains the physical mechanism and blade loading for deviations. The description and explanation are based on numerical simulations by means of RANS and RNG k-ε Model,corroborated by experiments. As a result,the non-uniform inflow has been proved as a major factor to weaken a waterjet pump,according to the blockage of an inlet distortion upstream the blade shroud and the considerable disturbance of a hub separation vortex. In detail,the inlet distortion is actually a circumferential separation vortex revolution from the lower energy flow of the non-uniform suction flow. The lower the attack angle,the higher the pattern of separation flow with consequent a spiral focus-type vortex on the pressure side of blade hub. Then,the crossflow gives rise to radial shedding of the separation vortex and the consequent formation of secondary flow and reverse flow. Meanwhile,the separation vortex reduces the bound vortex of the hub,with a drop of the lift owing to a mid-loaded distribution instead of the fore. Eventually,the separation,vortexes formation and propagation successively,explain the flow mechanism of the non-uniform inflow and the reduction of performance,maximum is 30%.
Insufficient understanding of large deviations between experiment performance and actual performance is a major problem encountered in the water-jet pump application. This study describes the non-uniform flow structure from the intake duct,and explains the physical mechanism and blade loading for deviations. The description and explanation are based on numerical simulations by means of RANS and RNG k-ε Model,corroborated by experiments. As a result,the non-uniform inflow has been proved as a major factor to weaken a waterjet pump,according to the blockage of an inlet distortion upstream the blade shroud and the considerable disturbance of a hub separation vortex. In detail,the inlet distortion is actually a circumferential separation vortex revolution from the lower energy flow of the non-uniform suction flow. The lower the attack angle,the higher the pattern of separation flow with consequent a spiral focus-type vortex on the pressure side of blade hub. Then,the crossflow gives rise to radial shedding of the separation vortex and the consequent formation of secondary flow and reverse flow. Meanwhile,the separation vortex reduces the bound vortex of the hub,with a drop of the lift owing to a mid-loaded distribution instead of the fore. Eventually,the separation,vortexes formation and propagation successively,explain the flow mechanism of the non-uniform inflow and the reduction of performance,maximum is 30%.
引文
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[8]Zangeneh M,Daneshkhah K,Da Costa B.A Multi Objective Automatic Optimization Strategy for Design of Waterjet Pumps[C].London:International Conference on Waterjet Propulsion V,2008.
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[16]刘瑞华,曹璞钰,王洋,等.无轴式喷水推进泵的水动力特性[J].排灌机械工程学报,2015,33(5).
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[18]Engeda A,Kim Y,Aungier R,et al.The Inlet Flow Structure of a Centrifugal Compressor Stage and Its Influence on the Compressor Performance[J].Journal of Fluids Engineering,2003,125(5):779-785.
[19]金平仲.船舶喷水推进[M].北京:国防工业出版社,1986.
[20]胡伟波,程邦勤,陈志敏,等.整体涡旋流畸变对压气机性能影响的研究[J].推进技术,2015,36(9):1324-1330.(HU Wei-bo,CHENG Bang-qin,CHEN Zhi-min,et al.Investigation on Effects of Bulk Swirl Distortion on Compressor Performance[J].Journal of Propulsion Technology,2015,36(9):1324-1330.)
[21]林万来,曾松祥,王立祥.轴流泵变轴向速度的研究及试验[A].船舶喷水推进及轴流式推进泵论文集[C].上海:中国船舶工业集团公司第708研究所,1991:172-179.
[22]马丁·宋贝,刘尚培.“伯努利升力原理”批判[J].力学与实践,1993,15(4).
[23]康顺,王仲奇.拓扑方法在叶栅三元流动分析中的应用(II):表面摩擦力矢量场和截面流线矢量场图画的拓扑分析[J].应用数学和力学,1990,11(12).
[24]Zangeneh M,Goto A,Harada H.On the Design Criteria for Suppression of Secondary Flows in Centrifugal and Mixed Flow Impellers[J].Journal of Turbomachinery,1997,120(4):723-735.
[2]Verbeek R.Recent Development in Waterjet Design[C].Amsterdam:International Conference on Water-Jet Propulsion II,1998.
[3]Tervisga V.The Effect of Waterjet-Hull Interaction on Thrust and Propulsion Efficiency[C].Trondheim:Proceedings of International Conference on Fast Sea Transportation Conference,1991.
[4]Hu P,Zangeneh M.Investigations of 3D Turbulent Flow Inside and Around a Water-Jet Intake Duct Under Different Operating Conditions[J].Journal of Fluids Engineering,1999,121(2):396-404.
[5]Seil G J.The Effect of the Shaft,Shaft Rotation and Scale on the Flow in Waterjet Inlets[C].Gothenburg:International Conference on Waterjet Propulsion III,2001.
[6]Bulten N W H.Numerical Analysis of Waterjet Propulsion System[D].Eindhoven:Technical University of Eindhoven,2006.
[7]魏应三,王永生.喷水推进器进水流道不均匀度统一描述[J].武汉理工大学学报,2009,30(8):159-163.
[8]Zangeneh M,Daneshkhah K,Da Costa B.A Multi Objective Automatic Optimization Strategy for Design of Waterjet Pumps[C].London:International Conference on Waterjet Propulsion V,2008.
[9]肖若富,陶然,王维维,等.混流泵叶轮反问题设计与水力性能优[J].农业机械学报,2014,45(9):1000-1298.
[10]Bonaiuti D,Zangeneh M,Aartojarvi R,et al.Parametric Design of a Waterjet Pump by Means of Inverse Design,CFD Calculations and Experimental Analyses[J].Journal of Fluids Engineering,2010,132(3).
[11]常书平,王永生,靳栓宝,等.载荷分布规律对混流泵叶轮设计的影响[J].排灌机械工程学报,2013,31(2):123-127.
[12]Van Esch B P M.Performance and Radial Loading of a Mixed-Flow Pump Under Non-Uniform Suction Flow[J].Journal of Fluids Engineering,2009,131(5).
[13]Svensson R,Grossi L.Trail Result Including Wake Measurements from the World’s Largest Waterjet Installation[C].Amsterdam:International Conference on Waterjet Propulsion II,1998.
[14]Bulten N W H,Verbeek R.CFD Simulations of the Flow Through a Waterjet Installation[C].London:International Conference on Waterjet Propulsion IV,2004.
[15]常书平,王永生.采用k-ε湍流模型的喷水推进器性能预报[J].华中科技大学学报,2012,40(4):88-90.
[16]刘瑞华,曹璞钰,王洋,等.无轴式喷水推进泵的水动力特性[J].排灌机械工程学报,2015,33(5).
[17]Kim Y,Engeda A,Aungier R,et al.The Influence of Inlet Flow Distortion on the Performance of a Centrifugal Compressor and the Development of an Improved Inlet Using Numerical Simulations[J].Proceedings of the Institution of Mechanical Engineers,Part A:Journal of Power&Energy,2001,215(3):323-338.
[18]Engeda A,Kim Y,Aungier R,et al.The Inlet Flow Structure of a Centrifugal Compressor Stage and Its Influence on the Compressor Performance[J].Journal of Fluids Engineering,2003,125(5):779-785.
[19]金平仲.船舶喷水推进[M].北京:国防工业出版社,1986.
[20]胡伟波,程邦勤,陈志敏,等.整体涡旋流畸变对压气机性能影响的研究[J].推进技术,2015,36(9):1324-1330.(HU Wei-bo,CHENG Bang-qin,CHEN Zhi-min,et al.Investigation on Effects of Bulk Swirl Distortion on Compressor Performance[J].Journal of Propulsion Technology,2015,36(9):1324-1330.)
[21]林万来,曾松祥,王立祥.轴流泵变轴向速度的研究及试验[A].船舶喷水推进及轴流式推进泵论文集[C].上海:中国船舶工业集团公司第708研究所,1991:172-179.
[22]马丁·宋贝,刘尚培.“伯努利升力原理”批判[J].力学与实践,1993,15(4).
[23]康顺,王仲奇.拓扑方法在叶栅三元流动分析中的应用(II):表面摩擦力矢量场和截面流线矢量场图画的拓扑分析[J].应用数学和力学,1990,11(12).
[24]Zangeneh M,Goto A,Harada H.On the Design Criteria for Suppression of Secondary Flows in Centrifugal and Mixed Flow Impellers[J].Journal of Turbomachinery,1997,120(4):723-735.