Venturi式掺混器几何参数对性能的影响
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摘要
微气泡发生器在污水处理中具有重要用途, Venturi式气液两相掺混器在微气泡生成方面具有众多优良特性.采用数值模拟方法研究了Venturi式掺混器结构几何参数对其掺混性能的影响.运用单一变量法分别研究了不同收缩段曲线,进气孔数目,扩张角的角度对掺混性能的影响,通过对比不同模型仿真结果的出口段气体体积分数、沿轴向压力变化及沿轴向湍动能变化,得出掺混性能最佳的几何参数.研究收缩段曲线时,发现一次直线的气液掺混性能在所选的5条收缩段曲线中最好;研究进气孔数量时,比较了1, 2, 4个进气孔对掺混性能的影响,发现在一定的进气孔数目范围内,进气孔数目的增加可以提高气液掺混效率;研究扩张角变化对掺混效率的影响时,得出在6～9°的范围内,随着扩张角的增大,气液掺混效率随之显著增大.
Microbubble generators have important applications in wastewater treatment. The Venturi gas-liquid two-phase blender has many excellent characteristics in the generation of microbubbles. In this paper, numerical simulation method was used to study the influence of geometric parameters of the Venturi-type blender on its blending performance. A single variable method was used to study the influence of the different shrinkage curves, the number of inlet holes, and the angles of expansion on the blending performance. By comparing the gas volume fraction of the outlet section, the pressure and turbulent kinetic energy variations along the axial of different models, the optimum geometric parameters of mixing performance were obtained. When studying the contraction curves, it was found that the gas-liquid blending performance of a straight line was the best among the five selected contraction curves. The number of intake holes was studied. The effects of one, two and four intake holes on the mixing performance were compared. It was found that the increase of the number of intake holes could improve the mixing efficiency within a certain range and the effect of the change in the expansion angle on the blending efficiency was found in this paper. In the studied range of 6 to 9°, with the increase of the expansion angle, the gas-liquid mixing efficiency increases significantly.
Microbubble generators have important applications in wastewater treatment. The Venturi gas-liquid two-phase blender has many excellent characteristics in the generation of microbubbles. In this paper, numerical simulation method was used to study the influence of geometric parameters of the Venturi-type blender on its blending performance. A single variable method was used to study the influence of the different shrinkage curves, the number of inlet holes, and the angles of expansion on the blending performance. By comparing the gas volume fraction of the outlet section, the pressure and turbulent kinetic energy variations along the axial of different models, the optimum geometric parameters of mixing performance were obtained. When studying the contraction curves, it was found that the gas-liquid blending performance of a straight line was the best among the five selected contraction curves. The number of intake holes was studied. The effects of one, two and four intake holes on the mixing performance were compared. It was found that the increase of the number of intake holes could improve the mixing efficiency within a certain range and the effect of the change in the expansion angle on the blending efficiency was found in this paper. In the studied range of 6 to 9°, with the increase of the expansion angle, the gas-liquid mixing efficiency increases significantly.
引文
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[11]李鹏,陆海峰,郭晓镭,等.文丘里管收缩段高固气比气固两相流压降模型[J].化学工程,2017,45(6):39-43.Li P,Lu H F,Guo X L,et al.Pressure drop model for gas/solid flow in contraction section of Venturi with high solid-gas ratio[J].Chemical Engineering(China),2017,45(6):39-43(in Chinese).
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[13]Cui P,Zhang A M,Wang S P,et al.Ice breaking by a collapsing bubble[J].Journal of Fluid Mechanics,2018,841:287-309.
[14]YU P N,XU Y,ZHANG T,et a1.A study on the modeling of static pressure distribution of wet gas in Venturi[J].Aiche Journal,2015,61(2):699-708.
[15]Fujiwara A,Takagi S,Matsumoto Y.Bubble breakup phenomena in a venturi tube[C].ASME/JSME 2007,Joint Fluids Engineering Conference,2007:553-560.
[16]Yin J,Li J,Li H,et al.Experimental study on the bubble generation characteristics for an Venturi type bubble generator[J].International Journal of Heat&Mass Transfer,2015,91:218-224.
[17]Gordiychuk A,Svanera M,Benini S,et al.Size distribution and Sauter mean diameter of micro bubbles for a Venturi type bubble generator[J].Experimental Thermal&Fluid Science,2016,70:51-60.
[18]Kress T S.Mass transfer between small bubbles and liquids in cocurrent turbulent pipeline flow[D].Tennessee University,Knoxville,1972.
[19]颜攀,黄正梁,王靖岱,等.文丘里气泡发生器的气泡尺寸及分布[J].浙江大学学报(工学版),2017,51(10):2070-2076.Yan P,Huang Z L,Wang J D,et al.Bubble size and distribution of Venturi bubble generator[J].Journal of Zhejiang University(Engineering Science),2017,51(10):2070-2076(in Chinese).
[20]曹俊雅,马梦杰,李平平,等.进气方向对文丘里微气泡发生器气泡直径的影响[J].黄金科学技术,2017,25(5):127-134.Cao J Y,Ma M J,Li P P,et al.Effect of air intake direction on bubble diameter of Venturi microbubble generator[J].Gold Science and Technology,2017,25(5):127-134(in Chinese).
[21]谢菲,吴占松.文丘里管内气固两相流动的数值模拟和实验[J].动力工程学报,2007,27(2):237-241.Xie F,Wu Z S.Numerical simulation and experiment of gas-solid two-phase flow in Venturi tubes[J].Journal of Power Engineering,2007,27(2):237-241(in Chinese).
[22]莫政宇,杜敏,邵梓一,等.文丘里式气泡发生器内气泡输运过程研究[J].原子能科学技术,2016,50(6):1034-1039.Mo Z Y,Du M,Shao Z Y,et al.Study on bubble transport process in Venturi bubble generator[J].Atomic Energy Science and Technology,2016,50(6):1034-1039(in Chinese).
[2]管金发,邓松圣,张攀峰,等.文丘里管空化装置设计与数值模拟[J].后勤工程学院学报,2012,28(3):30-34.Guan J F,Deng S S,Zhang P F,et al.Design and numerical simulation of Venturi tube hydrodynamic cavitation equipment[J].Journal of Logistical Engineering University,2012,28(3):30-34(in Chinese).
[3]Barre S,Rolland J,Boitel G,et al.Experiments and modeling of cavitating flows in Venturi:attached sheet cavitation[J].European Journal of Mechanics-B/Fluids,2009,28(3):444-464.
[4]Uesawa S I,Kaneko A,Nomura Y,et al.Study on bubble breakup behavior in a Venturi tube[J].Multiphase Science and Technology,2012,24(3):257-277.
[5]Nomura Y,Uesawa S I,Kaneko A,et al.Study on bubble breakup mechanism in a Venturi tube[C].Proceedings of ASME-JSME-KSME 2011 Joint Fluids Engineering Conference,Hamamatsu:ASME,2011:2533-2540.
[6]王淼,黄兴法,李光永.文丘里施肥器性能数值模拟研究[J].农业工程学报,2006,22(7):27-31.Wang M,Huang X F,Li G Y.Numerical simulation of characteristics of Venturi Injector[J].Transactions of the CSAE,2006,22(7):27-31(in Chinese).
[7]马宁宁.开孔文丘里管掺气水流的水力和增氧特性研究[D].青岛:中国海洋大学,2015.Ma N N.Hydraulic and reoxygenation of characteristic research on aeration flow in Venturi tube with perforates[D].Qingdao:Ocean University of China,2015(in Chinese).
[8]居晓峰,孙立成,唐文偲,等.文丘里式气泡发生器工作特性分析[J].核技术,2014,37(12):67-72.Ju X F,Sun L C,Tang W C,et al.Analysis of the operating characteristics of a Venturi-type bubble generator for MSR[J].Nuclear Techniques,2014,37(12):67-72(in Chinese).
[9]Kaneko A,Nomura Y,Shu T,et al.Bubble break-up phenomena in a Venturi tube[J].Nihon Kikai Gakkai Ronbunshu B Hen/transactions of the Japan Society of Mechanical Engineers Part B,2007,78(786):207-217.
[10]岳伟挺.基于文丘里管的气液两相流参数检测方法研究[D].杭州:浙江大学,2004.Yue W T.Research on gas-liquid two-phase flow parameters measurement with Venturi tube[D].Hangzhou:Zhejiang University,2004(in Chinese).
[11]李鹏,陆海峰,郭晓镭,等.文丘里管收缩段高固气比气固两相流压降模型[J].化学工程,2017,45(6):39-43.Li P,Lu H F,Guo X L,et al.Pressure drop model for gas/solid flow in contraction section of Venturi with high solid-gas ratio[J].Chemical Engineering(China),2017,45(6):39-43(in Chinese).
[12]唐文偲,阎昌琪,孙立成,等.文丘里式气泡发生器气泡碎化特性研究[J].原子能科学技术,2014,48(5):844-848.Tang W C,Yan C Q,Sun L C,et al.Characteristic of bubble breakup in Venturi-type bubble generator[J].A-tomic Energy Science and Technology,2014,48(5):844-848(in Chinese).
[13]Cui P,Zhang A M,Wang S P,et al.Ice breaking by a collapsing bubble[J].Journal of Fluid Mechanics,2018,841:287-309.
[14]YU P N,XU Y,ZHANG T,et a1.A study on the modeling of static pressure distribution of wet gas in Venturi[J].Aiche Journal,2015,61(2):699-708.
[15]Fujiwara A,Takagi S,Matsumoto Y.Bubble breakup phenomena in a venturi tube[C].ASME/JSME 2007,Joint Fluids Engineering Conference,2007:553-560.
[16]Yin J,Li J,Li H,et al.Experimental study on the bubble generation characteristics for an Venturi type bubble generator[J].International Journal of Heat&Mass Transfer,2015,91:218-224.
[17]Gordiychuk A,Svanera M,Benini S,et al.Size distribution and Sauter mean diameter of micro bubbles for a Venturi type bubble generator[J].Experimental Thermal&Fluid Science,2016,70:51-60.
[18]Kress T S.Mass transfer between small bubbles and liquids in cocurrent turbulent pipeline flow[D].Tennessee University,Knoxville,1972.
[19]颜攀,黄正梁,王靖岱,等.文丘里气泡发生器的气泡尺寸及分布[J].浙江大学学报(工学版),2017,51(10):2070-2076.Yan P,Huang Z L,Wang J D,et al.Bubble size and distribution of Venturi bubble generator[J].Journal of Zhejiang University(Engineering Science),2017,51(10):2070-2076(in Chinese).
[20]曹俊雅,马梦杰,李平平,等.进气方向对文丘里微气泡发生器气泡直径的影响[J].黄金科学技术,2017,25(5):127-134.Cao J Y,Ma M J,Li P P,et al.Effect of air intake direction on bubble diameter of Venturi microbubble generator[J].Gold Science and Technology,2017,25(5):127-134(in Chinese).
[21]谢菲,吴占松.文丘里管内气固两相流动的数值模拟和实验[J].动力工程学报,2007,27(2):237-241.Xie F,Wu Z S.Numerical simulation and experiment of gas-solid two-phase flow in Venturi tubes[J].Journal of Power Engineering,2007,27(2):237-241(in Chinese).
[22]莫政宇,杜敏,邵梓一,等.文丘里式气泡发生器内气泡输运过程研究[J].原子能科学技术,2016,50(6):1034-1039.Mo Z Y,Du M,Shao Z Y,et al.Study on bubble transport process in Venturi bubble generator[J].Atomic Energy Science and Technology,2016,50(6):1034-1039(in Chinese).