环形自激振荡射流泵在气液掺混传质中的应用
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摘要
较传统环形射流泵而言,环形自激振荡射流泵,可以在无外界激励的作用下仅靠自身合理的尺寸设计在自激振荡腔室内形成循环的振荡效果,利用自激振荡腔室产生的强烈自激振荡涡旋来提高气液两相传质的效果。本文采用计算与实验相结合的方法,使用k-ε湍流模型对环形自激振荡射流泵进行CFD(Computational fluid dynamics)流场仿真,并针对脱氧后的水溶解氧的能力进行了研究。结果表明,环形自激振荡射流泵掺混能力较传统环形射流泵提升15%～20%,与传统曝气头相比,混合能力提升30%以上。混合过程中由于自激振荡产生的脉冲效果使气相和液相之间产生了剧烈的剪切场,在剪切力的作用下使混合液中的气泡数量增多,气泡粒径变小,从而增加了气相与液相接触的面积,进而达到提高气液两相掺混传质的目的。
Compared with the conventional annular jet pump,the annular self-excited oscillating jet pump can form a circular oscillation effect in the self-excited oscillating chamber only by its own reasonable size design without external excitation. The self-excited oscillation chamber generates a strong self-oscillating vortex to enhance the effect of gas-liquid two-phase mass transfer. In this paper,a three-dimensional computational fluid dynamics of a ring-shaped self-oscillating jet pump is performed using the k-ε turbulence model and combining computational and experimental methods. The ability of dissolved oxygen in water after deoxygenation is studied. The results show that the mixing capacity of the annular self-oscillating jet pump is 15% ～ 20% higher than that of the traditional annular jet pump. Compared with the traditional aerator,the mixing capacity is increased by more than 30%. In the mixing process,the pulse effect due to self-oscillation causes a sharp shear field between the gas phase and the liquid phase. Under the action of the shear force,the number of bubbles in the mixed liquid increases,and the bubble particle size becomes smaller,thereby increasing the area in which the gas and liquid phases are in contact with each other increases the mass transfer of the gas-liquid two-phase mixture.
Compared with the conventional annular jet pump,the annular self-excited oscillating jet pump can form a circular oscillation effect in the self-excited oscillating chamber only by its own reasonable size design without external excitation. The self-excited oscillation chamber generates a strong self-oscillating vortex to enhance the effect of gas-liquid two-phase mass transfer. In this paper,a three-dimensional computational fluid dynamics of a ring-shaped self-oscillating jet pump is performed using the k-ε turbulence model and combining computational and experimental methods. The ability of dissolved oxygen in water after deoxygenation is studied. The results show that the mixing capacity of the annular self-oscillating jet pump is 15% ～ 20% higher than that of the traditional annular jet pump. Compared with the traditional aerator,the mixing capacity is increased by more than 30%. In the mixing process,the pulse effect due to self-oscillation causes a sharp shear field between the gas phase and the liquid phase. Under the action of the shear force,the number of bubbles in the mixed liquid increases,and the bubble particle size becomes smaller,thereby increasing the area in which the gas and liquid phases are in contact with each other increases the mass transfer of the gas-liquid two-phase mixture.
引文
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[9]龙新平,鄢恒飞,张松艳,等.喉管长度对环形射流泵性能影响的数值模拟[J].排灌机械工程学报,2010,28(3):198-201,206Long X P,Yan H F,Zhang S Y,et al. Numerical simulation for influence of throat length on annular jet pump performance[J]. Journal of Drainage and Irrigation Machinery Engineering,2010,28(3):198-201,206(in Chinese)
[10]邓晓刚,张贤明.环形水气自激振荡射流卷吸特性模拟及优化[J].真空科学与技术学报,2013,33(11):1080-1085Deng X G,Zhang X M. Improvement of air extracting characteristics for annular water-air self-excited oscillation jet[J]. Chinese Journal of Vacuum Science and Technology, 2013,33(11):1080-1085(in Chinese)
[11]洪守胜.环形自激振荡射流泵设计及其性能研究[D].武汉:武汉科技大学,2016Hong S S. The design and performance research of annular self-oscillating jet pump[D]. Wuhan:Wuhan University of Science and Technology, 2016(in Chinese)
[12]张强.流动诱导空腔振荡频率方程的改进[J].振动工程学报,2004,17(1):53-57Zhang Q. Development of the frequency equation used for prediction of fluid induced pressure oscillation in cavities[J]. Journal of Vibration Engineering,2004,17(1):53-57(in Chinese)
[13]杨雪龙.环形射流泵内部流动机理及结构优化研究[D].武汉:武汉大学,2014Yang X L. Research on the flow mechanism and structure optimization of annular jet pumps[D]. Wuhan:Wuhan University,2014(in Chinese)
[14]高全杰,李海洋,汪朝晖,等.环形自激振荡射流泵内部流动特性的数值模拟[J].机械设计与制造,2017(7):103-106Gao Q J,Li H Y,Wang C H,et al. Numerical simulation for characteristics of the internal flow on annular selfexcited oscillation jet pump[J]. Machinery Design&Anufacture,2017(7):103-106(in Chinese)
[15]邓晓刚,曹柳.环形水气自激振荡射流泵提高传能效率分析与计算[J].机械科学与技术,2018,37(3):396-401Deng X G,Cao L. Analysis and numerical simulation of entrainment efficiency in annular water-air selfoscillating jet pump[J]. Mechanical Science and Technology for Aerospace Engineering,2018,37(3):396-401(in Chinese)
[16]王超,肖晓愚,江大波,等.一种增大气液传质界面途径的探讨[J].化肥设计,2018,56(2):22-24Wang C,Xiao X Y,Jiang D B,et al. An exploration on a way to increase gas-liquid mass transfer interface[J].Chemical Fertilizer Design,2018,56(2):22-24(in Chinese)
[2]陆宏圻.射流泵技术的理论及应用[M].北京:水利水电出版社,1989:5-15Lu H Q. The theory and application of jet pump technology[M]. Beijing:China Water and Power Press,1989:5-15(in Chinese)
[3]李江云,徐如良,王乐勤.自激脉冲喷嘴发生机理数值模拟[J].工程热物理学报,2004,25(2):241-243Li J Y,Xu R L,Wang L Q. Numerical simulation of mechanism of the self-excited pulse nozzle[J]. Journal of Engineering Thermophysics, 2004,25(2):241-243(in Chinese)
[4] Winoto S H,Li H,Shah D A. Efficiency of jet pumps[J].Journal of Hydraulic Engineering,2000,126(2):150-156
[5] Dirix C A M C,Wiele K V D. Mass transfer in jet loop reactors[J]. Chemical Engineering Science,1990,45(8):2333-2340
[6] Evans G M,Jameson G J,Atkinson B W. Prediction of the bubble size generated by a plunging liquid jet bubble column[J]. Chemical Engineering Science,1992,47(13-14):3265-3272
[7]向清江,王超,吴燕兰,等.液气射流泵扩散管内部流动试验研究[J].排灌机械工程学报,2014,32(7):558-562Xiang Q J,Wang C,Wu Y L,et al. Experimental study on flow in diffuser of liquid-jet gas pump[J]. Journal of Drainage and Irrigation Machinery Engineering(JDIME),2014,32(7):558-562(in Chinese)
[8]曾庆龙,龙新平,肖龙洲,等.环形射流泵结构优化设计[J].排灌机械工程学报,2014,32(2):98-102Zeng Q L, Long X P, Xiao L Z, et al. Structure optimization of annular jet pumps[J]. Journal of Drainage and Irrigation Machinery Engineering,2014,32(2):98-102(in Chinese)
[9]龙新平,鄢恒飞,张松艳,等.喉管长度对环形射流泵性能影响的数值模拟[J].排灌机械工程学报,2010,28(3):198-201,206Long X P,Yan H F,Zhang S Y,et al. Numerical simulation for influence of throat length on annular jet pump performance[J]. Journal of Drainage and Irrigation Machinery Engineering,2010,28(3):198-201,206(in Chinese)
[10]邓晓刚,张贤明.环形水气自激振荡射流卷吸特性模拟及优化[J].真空科学与技术学报,2013,33(11):1080-1085Deng X G,Zhang X M. Improvement of air extracting characteristics for annular water-air self-excited oscillation jet[J]. Chinese Journal of Vacuum Science and Technology, 2013,33(11):1080-1085(in Chinese)
[11]洪守胜.环形自激振荡射流泵设计及其性能研究[D].武汉:武汉科技大学,2016Hong S S. The design and performance research of annular self-oscillating jet pump[D]. Wuhan:Wuhan University of Science and Technology, 2016(in Chinese)
[12]张强.流动诱导空腔振荡频率方程的改进[J].振动工程学报,2004,17(1):53-57Zhang Q. Development of the frequency equation used for prediction of fluid induced pressure oscillation in cavities[J]. Journal of Vibration Engineering,2004,17(1):53-57(in Chinese)
[13]杨雪龙.环形射流泵内部流动机理及结构优化研究[D].武汉:武汉大学,2014Yang X L. Research on the flow mechanism and structure optimization of annular jet pumps[D]. Wuhan:Wuhan University,2014(in Chinese)
[14]高全杰,李海洋,汪朝晖,等.环形自激振荡射流泵内部流动特性的数值模拟[J].机械设计与制造,2017(7):103-106Gao Q J,Li H Y,Wang C H,et al. Numerical simulation for characteristics of the internal flow on annular selfexcited oscillation jet pump[J]. Machinery Design&Anufacture,2017(7):103-106(in Chinese)
[15]邓晓刚,曹柳.环形水气自激振荡射流泵提高传能效率分析与计算[J].机械科学与技术,2018,37(3):396-401Deng X G,Cao L. Analysis and numerical simulation of entrainment efficiency in annular water-air selfoscillating jet pump[J]. Mechanical Science and Technology for Aerospace Engineering,2018,37(3):396-401(in Chinese)
[16]王超,肖晓愚,江大波,等.一种增大气液传质界面途径的探讨[J].化肥设计,2018,56(2):22-24Wang C,Xiao X Y,Jiang D B,et al. An exploration on a way to increase gas-liquid mass transfer interface[J].Chemical Fertilizer Design,2018,56(2):22-24(in Chinese)