高压环境下剪切稀化非牛顿撞击射流直接数值模拟
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摘要
高压环境下的撞击射流是液体火箭推进系统中广泛采用的一种燃料雾化方法,其雾化效果将直接决定最终燃烧效率。采用直接数值模拟(DNS)工具,对10MPa高压环境下剪切稀化非牛顿直角撞击射流的三维非定常雾化特征、机理及非牛顿特性进行了研究。结果表明:高压环境下该撞击射流的雾化流场呈圆形辐射状分布并形成Mushroom头部和Ω状的局部凸起,气体中的涡量分布表现为有序贴附区和无序爆炸区两类,液膜向液丝的破碎主要受平均气体力和平均黏性力作用影响,而液丝向液滴的破碎则主要受局部流场参数影响,撞击雾化过程中液体无量纲表面积不断增长并可分为5个阶段。此外,撞击射流头部在局部强剪切力作用下其无量纲黏性系数最低降至仅0.7。
Impinging liquid jets have been widely used in liquid rocket propulsion systems as a fuel atomization method.The breakup efficiency of impinging liquid jets directly determines the mixing and combustion efficiency of the fuel.The present work applies a Direct Numerical Simulation(DNS)tool to study the three-dimensional unsteady impinging jet breakup with non-Newtonian shear thinning properties at high ambient pressure 10 MPa,including the three-dimensional structure,breakup mechanism,and non-Newtonian feature of the liquid.The results indicate that the impinging jet breakup exhibits a radial circular flow structure and forms a Mushroom head and anΩshape local protruding.The distribution of gas vorticity is split into two categories that include the regulated attached region and irregular blasting region.The breakup from liquid sheet to ligament is determined by the average air force and viscous force,whereas the breakup from ligament to droplet is determined by local flow parameters.The dimensionless liquid surface area increases with time and can be divided into five phases.Additionally,the non-dimensional viscosity of the liquid at the impinging jet head decreases to only 0.7 due to high local shear stresses.
Impinging liquid jets have been widely used in liquid rocket propulsion systems as a fuel atomization method.The breakup efficiency of impinging liquid jets directly determines the mixing and combustion efficiency of the fuel.The present work applies a Direct Numerical Simulation(DNS)tool to study the three-dimensional unsteady impinging jet breakup with non-Newtonian shear thinning properties at high ambient pressure 10 MPa,including the three-dimensional structure,breakup mechanism,and non-Newtonian feature of the liquid.The results indicate that the impinging jet breakup exhibits a radial circular flow structure and forms a Mushroom head and anΩshape local protruding.The distribution of gas vorticity is split into two categories that include the regulated attached region and irregular blasting region.The breakup from liquid sheet to ligament is determined by the average air force and viscous force,whereas the breakup from ligament to droplet is determined by local flow parameters.The dimensionless liquid surface area increases with time and can be divided into five phases.Additionally,the non-dimensional viscosity of the liquid at the impinging jet head decreases to only 0.7 due to high local shear stresses.
引文
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[22] SCHROEDER J,LEDERER M L,GAUKEL V,et al.Effect of atomizer geometry and rheological properties on effervescent atomization of aqueous polyvinylphrrolidone solution[C]∥24th ILASS Europe,2011.
[23] ZHU C X,ERTL M,WEIGAND B.Numerical investigation on the primary breakup of an inelastic non-Newtonian liquid jet with inflow turbulence[J].Physics of Fluids,2013,25:083102.
[24]朱呈祥,尤延铖.横向气流中非牛顿液体射流直接数值模拟[J].航空学报,2016,37(9):2659-2668.ZHU C X,YOU Y C.Direct numerical simulation of a non-Newtonian liquid jet in crossflow[J].Acta Aeronautica et Astronautica Sinica,2016,37(9):2659-2668(in Chinese).
[25]朱呈祥,陈荣钱,尤延铖,低韦伯数非牛顿射流撞击破碎直接数值模拟[J].航空学报,2017,38(8):120764.ZHU C X,CHEN R Q,YOU Y C.Direct numerical simulation of impinging jet breakup with non-Newtonian properties at low Weber number[J].Acta Aeronautica et Astronautica Sinica,2017,38(8):120764(in Chinese).
[26]朱呈祥,吴猛,陈荣钱,等.剪切稀化非牛顿射流撞击液膜破碎直接数值模拟[J].航空学报,2018,39(5):121982.ZHU C X,WU M,CHEN R Q,et al.Direct numerical simulation of sheet breakup formed y two impinging jets with non-Newtonian shear thinning properties[J].Acta Aeronautica et Astronautica Sinica,2018,39(5):121982(in Chinese).
[27] BATCHELOR G K.The theory of homogeneous turbulence[M].Cambridge:Cambridge University Press,1953:133-168.
[28] BREMOND N,CLANET C,VILLERMAUX E.Atomization of undulating liquid sheets[J].Journal of Fluid Mechanics,2007,585:421-456.
[29] SHINJO J,UMEMURA A.Simulation of liquid jet primary breakup:Dynamics of ligament and droplet formation[J].International Journal of Multiphase Flow,2010,36(7):513-532.
[2] SHIM Y S,CHOI G M,KIM D J.Numerical and experimental study on hollow-cone fuel spray of high pressure swirl injector under high ambient pressure condition[J].Journal of Mechanical Science&Technology,2008,22(2):320-329.
[3] JUNG K,LIM B,KHIL T,et al.Breakup characteristics of laminar and turbulent liquid sheets formed by impinging jets in high pressure environments[C]∥AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit.Reston,VA:AIAA、2013.
[4] KAMPEN J V,CIEZKI H K,TIEDT T,et al.Some aspects of the atomization behavior of Newtonian and of shear-thinning gelled non-Newtonian fluids with an impinging jet injector[C]∥Spray Workshop,2006.
[5] LEE J G,FAKHI S,YETTER R.Atomization and spray characteristics of gelled-propellant simulants formed by two impinging jets[C]∥AIAA/ASME/SAE/ASEE Joint Propulsion Conference&Exhibit.Reston,VA:AIAA,2009.
[6]杜青,杨子明,白富强,等.高环境压力下幂律流体射流液滴粒度特性试验[J].天津大学学报(自然科学与工程技术版),2017,50(7):689-695.DU Q,YANG Z M,BAI F Q,et al.Experiment on droplets size distribution of the cylindrical power-law liquid jet under high ambient pressure[J].Journal of Tianjin University(Science and Technology),2017,50(7):689-695(in Chinese).
[7]成晓北,鞠洪玲.高压喷射雾化液滴的二次破碎机理[J].华中科技大学学报(自然科学版),2008,36(10):125-128.CHENG X B,JU H L.Secondary breakup mechanisms of ajet atomized liquid drop[J].Journal of Huazhong University of Science&Technology(Natural Science Edition),2008,36(10):125-128(in Chinese).
[8]曹伟.幂律流体双股射流碰撞雾化的试验研究[D].哈尔滨:哈尔滨工业大学,2016.CAO W.Experimental study on the atomization characteristics of impinging jets of power-law fluids[D].Harbin:Harbin Institute of Technology,2016(in Chinese).
[9]夏振炎,李珍妮,李建军,等.撞击式射流破碎特性的实验研究[J].天津大学学报,2016,49(7):770-776.XIA Z Y,LI Z N,LI J J,et al.An experimental study on breakup characteristics of impinging jets[J].Journal of Tianjin University,2016,49(7):770-776(in Chinese).
[10]邓寒玉,封锋,武晓松,等.基于扩展TAB模型的凝胶液滴二次雾化特性研究[J].推进技术,2015,36(11):1734-1740.DENG H Y,FENG F,WU X S,et al.Characteristics of second atomization for gelled droplet based on extended TAB model[J].Journal of Propulsion Technology,2015,36(11):1734-1740(in Chinese).
[11] BAI B F,ZHANG H B,LIU L,et al.Experimental study on turbulent mixing of spray droplets in crossflow[J].Experimental Thermal and Fluid Science,2009,33(6):1012-1020.
[12] XIAO H,SHI Y,XU Z,et al.Atomization characteristics of gelled hypergolic propellant simulants[J].International Journal of Precision Engineering and Manufacturing,2015,16(4):743-747.
[13] HUO Y P,WANG J F,ZUO Z W,et al.Visualization of the evolution of charged droplet formation and jet transition in electrostatic atomization[J].Physics of Fluids,2015,27(11):114105.
[14] HIRT C W,NICHOLS B D.Volume of fluid(VOF)method for the dynamics of free boundaries[J].Journal of Computational Physics,1981,39:201-225.
[15] RIDER W J,KOTHE D B.Reconstructing volume tracking[J].Journal of Computational Physics,1998,141:112-152.
[16] SCHLOTTKE J,WEIGAND B.Direct numerical simulation of evaporating droplets[J].Journal of Computational Physics,2008,227:5215-5237.
[17] GOMMA H,KUMAR S,HUBER C,et al.Numerical comparison of 3Djet breakup using a compression scheme and an interface reconstruction based VOF-code[C]∥24th ILASS Europe,2011.
[18] MATSUHISA S,BIRD R B.Analytical and numerical solutions for laminar flow of the non-Newtonian Ellis fluids[J].AIChE Journal,1965,11:588-595.
[19]杨卫东,张蒙正,凝胶推进剂流变及雾化特性研究与进展[J].火箭推进,2005,31(5):37-42.YANG W D,ZHANG M Z.Research and development of rheological and atomization characteristics of gelled propellants[J].Journal of Rocket Propulsion,2005,31(5):37-42(in Chinese).
[20] MOTZIGEMBA M,ROTH N,BOTHE D,et al.The effect of non-Newtonian flow behavior on binary droplet collisions:VOF-simulation and experimental analysis[C]∥18th ILASS-Europe,2002.
[21] FOCKE C,BOTHE D.Computational analysis of binary collisions of shear thinning droplets[J].Journal of NonNewtonian Fluid Mechanics,2011,166:799-810.
[22] SCHROEDER J,LEDERER M L,GAUKEL V,et al.Effect of atomizer geometry and rheological properties on effervescent atomization of aqueous polyvinylphrrolidone solution[C]∥24th ILASS Europe,2011.
[23] ZHU C X,ERTL M,WEIGAND B.Numerical investigation on the primary breakup of an inelastic non-Newtonian liquid jet with inflow turbulence[J].Physics of Fluids,2013,25:083102.
[24]朱呈祥,尤延铖.横向气流中非牛顿液体射流直接数值模拟[J].航空学报,2016,37(9):2659-2668.ZHU C X,YOU Y C.Direct numerical simulation of a non-Newtonian liquid jet in crossflow[J].Acta Aeronautica et Astronautica Sinica,2016,37(9):2659-2668(in Chinese).
[25]朱呈祥,陈荣钱,尤延铖,低韦伯数非牛顿射流撞击破碎直接数值模拟[J].航空学报,2017,38(8):120764.ZHU C X,CHEN R Q,YOU Y C.Direct numerical simulation of impinging jet breakup with non-Newtonian properties at low Weber number[J].Acta Aeronautica et Astronautica Sinica,2017,38(8):120764(in Chinese).
[26]朱呈祥,吴猛,陈荣钱,等.剪切稀化非牛顿射流撞击液膜破碎直接数值模拟[J].航空学报,2018,39(5):121982.ZHU C X,WU M,CHEN R Q,et al.Direct numerical simulation of sheet breakup formed y two impinging jets with non-Newtonian shear thinning properties[J].Acta Aeronautica et Astronautica Sinica,2018,39(5):121982(in Chinese).
[27] BATCHELOR G K.The theory of homogeneous turbulence[M].Cambridge:Cambridge University Press,1953:133-168.
[28] BREMOND N,CLANET C,VILLERMAUX E.Atomization of undulating liquid sheets[J].Journal of Fluid Mechanics,2007,585:421-456.
[29] SHINJO J,UMEMURA A.Simulation of liquid jet primary breakup:Dynamics of ligament and droplet formation[J].International Journal of Multiphase Flow,2010,36(7):513-532.