液-液喷射器性能优化及内部流动特性分析?
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摘要
为了探索液-液喷射器的性能优化问题,改变喷射器喷嘴结构和射流类型,设计并建立了4种喷射器的三维模型,采用大涡模拟方法对4种模型进行模拟,得到各喷射器的内部流动特性及工作性能。工作流体从喷嘴射入吸入室,压力沿轴线呈现对称性的下降趋势,使得引射流体被卷吸进入喷射器并与工作流体进行掺混。随着两股流体的混合,势流核心区缩小,中速流体区域扩大,最终在扩散段内完成混合。通过分析各喷射器的内部流动特性,比较出4种喷射器的性能优劣。结果表明:椭圆喷嘴脉冲射流喷射器的卷吸性能、混合性能、效率均优于其他3种喷射器。
In order to optimize the performance of liquid-liquid ejectors, nozzle structures and jet types of ejectors were adjusted, and three-dimensional models of four ejectors were designed. A large eddy simulation method was used to study the internal flow characteristics and performance of these models. Working fluids were ejected from nozzles into a suction chamber and the pressure symmetrically decreased along the axis.Therefore, suction fluids were entrained into the ejector and mixed with working fluids. The potential core reduced and the medium-speed fluid area expanded, which completely mixed with each other in the diffuser.The performance of the four ejectors was compared by analyzing the internal flow characteristics. The results show the elliptical nozzle pulsed jet ejector has superior entrainment performance, mixing performance and efficiency than the other three ejectors.
In order to optimize the performance of liquid-liquid ejectors, nozzle structures and jet types of ejectors were adjusted, and three-dimensional models of four ejectors were designed. A large eddy simulation method was used to study the internal flow characteristics and performance of these models. Working fluids were ejected from nozzles into a suction chamber and the pressure symmetrically decreased along the axis.Therefore, suction fluids were entrained into the ejector and mixed with working fluids. The potential core reduced and the medium-speed fluid area expanded, which completely mixed with each other in the diffuser.The performance of the four ejectors was compared by analyzing the internal flow characteristics. The results show the elliptical nozzle pulsed jet ejector has superior entrainment performance, mixing performance and efficiency than the other three ejectors.
引文
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[14]ALLOUCHE Y,BOUDEN C,VARGA S.A CFD analysis of the flow structure inside a steam ejector to identify the suitable experimental operating conditions for a solar-driven refrigeration system[J].International Journal of Refrigeration,2014,39(1):186-195.
[15]HUNT J C R,WRAY A A,Moin P.Eddies,streams,and convergence zones in turbulent flows[C]//Studying Turbulence Using Numerical Simulation Databases.California:Center for Turbulence Research,1988:193-208.
[16]FU W S,LAI Y C,LI C G.Estimation of turbulent natural convection in horizontal parallel plates by the Q criterion[J].International Communications in Heat&Mass Transfer,2013,45(7):41-46.
[2]毕荣山,谭心舜,林柯利,等.结构尺寸对液-液喷射器湍流混合性能的影响[J].高校化学工程学报,2010,24(5):752-757.BI R S,TAN X S,LIN K L,et al.The effect of configuration diminsion on turulent mixing in liquid-liquid ejectors[J].Journal of Chemical Engineering of Chinese Universities,2010,24(5):752-757.
[3]耿利红,马新灵,魏新利,等.喷射器几何结构对压缩/喷射制冷循环性能的影响研究[J].高校化学工程学报,2015,29(5):1073-1081.GENG L H,MA X L,WEI X L,et al.Effects of ejector geometry on performance of compression/ejection refrigeration cycle[J].Journal of Chemical Engineering of Chinese Universities,2015,29(5):1073-1081.
[4]DAOTONG CHONG Q Z F Y.Research on the steam jet length with different nozzle structures[J].Experimental Thermal and Fluid Science,2015,64:134-141.
[5]CHANG Y J,CHEN Y M.Enhancement of a steam-jet refrigerator using a novel application of the petal nozzle[J].Experimental Thermal&Fluid Science,2000,23(6):677-686.
[6]GUILLAUME D W,JUDGE T A.Improving the efficiency of a jet pump using an elliptical nozzle[J].Review of Scientific Instruments,1999,70(12):4727-4729.
[7]YANG X,LONG X,YAO X.Numerical investigation on the mixing process in a steam ejector with different nozzle structures[J].International Journal of Thermal Sciences,2012,56:95-106.
[8]别海燕,李春红,安维中,等.喷嘴结构对液-液喷射器性能影响的CFD模拟[J].计算机与应用化学,2016,33(10):1068-1073.BIE H Y,LI C H,AN W Z,et al.CFD simulation of the influence of nozzle structure on the performance of liquid-liquid ejector[J].Computers and Applied Chemistry,2016,33(10):1068-1073.
[9]王玲花,高传昌.脉冲射流泵研究进展[J].水利电力机械,2006,28(6):33-35.WANG L H,GAO C C.Study progress of pulse jet pump[J].Water Conservancy&Electric Power Machinery,2006,28(6):33-35.
[10]CROW S C,CHAMPAGNE F H.Orderly structure in jet turbulence[J].Fluid Mechanics,1971,48(3):547-591.
[11]王玲花,高传昌,王为术,等.脉冲频率对液体喷射泵性能影响的试验研究[J].水利学报,2008,39(3):318-324.WANG L H,GAO C C,WANG W S,et al.Experimental study on effect of pulse frequency on performance of pulse liquid jet pump[J].Journal of Hydraulic Engineering,2008,39(3):318-324.
[12]BIE H Y,LI C H,AN W Z,et al.CFD simulation of the effect of pulsed jet on the performance of liquid-liquid ejector[J].Chemical engineering transactions,2017,61:865-870.
[13]SMAGORINSKY J S.General circulation experiments with the primitive equations[J].Monthly Weather Review,1963,91(1):99-164.
[14]ALLOUCHE Y,BOUDEN C,VARGA S.A CFD analysis of the flow structure inside a steam ejector to identify the suitable experimental operating conditions for a solar-driven refrigeration system[J].International Journal of Refrigeration,2014,39(1):186-195.
[15]HUNT J C R,WRAY A A,Moin P.Eddies,streams,and convergence zones in turbulent flows[C]//Studying Turbulence Using Numerical Simulation Databases.California:Center for Turbulence Research,1988:193-208.
[16]FU W S,LAI Y C,LI C G.Estimation of turbulent natural convection in horizontal parallel plates by the Q criterion[J].International Communications in Heat&Mass Transfer,2013,45(7):41-46.