缩放管-液固两相流换热器的流场特征影响因素  

Influencing factors of flow field characteristics of liquid-solid two-phase flow in converging-diverging tube heat exchangers

作　　者：彭德其[1] 刘建 付翁 俞天兰[2] 谭卓伟 吴淑英[1] 李方 PENG Deqi;LIU Jian;FU Weng;YU Tianlan;TAN Zhuowei;WU Shuying;LI Fang(School of Mechanical Engineering and Mechanics,Xiangtan University,Xiangtan 411105,China;School of Mechanical Engineering,Hunan University of Technology,Zhuzhou 412007,China)

机构地区：[1]湘潭大学机械工程与力学学院,湖南湘潭411105 [2]湖南工业大学机械工程学院,湖南株洲412007

出　　处：《中国粉体技术》2025年第3期67-77,共11页China Powder Science and Technology

基　　金：国家自然科学基金项目,编号:5217525;湖南省自然科学基金项目,编号:2024JJ7546。

摘　　要：【目的】研究缩放管内液固两相流的流场特征,实现缩放管-液固两相流换热器的优化设计。【方法】搭建可视化实验平台,采用粒子图像测速技术对立式上行缩放管内液固两相流流场特征进行研究,探索入口处流体速度、颗粒体积分数和颗粒粒径对缩放管内流体径向速度和涡量的影响规律。【结果】液固两相流的径向速度的峰值出现在轴向高度大约为0、6、24mm处,即扩放段与收缩段的交接处;平均径向速度随着入口处流体速度、颗粒体积分数的增大而增大,随着颗粒粒径的增大而减小;涡量在管壁附近最大而在管中心处最小,整体平均涡量与近壁区域平均涡量均随着入口处流体速度、颗粒体积分数的增大而增大,随着颗粒粒径的增大而减小;在入口处流体速度为1.0m/s、颗粒体积分数为5%、颗粒粒径为1.5mm的条件下,缩放管-液固两相流换热管内的流体运动最为剧烈,能有效促进管内传质与传热作用。【结论】在缩放管-液固两相流换热器中,液固两相流的平均径向速度的影响因素由强到弱依次为入口处流体速度、颗粒体积分数、颗粒粒径;近壁区域液固两相流的平均涡量的影响因素由强到弱依次为入口处流体速度、颗粒体积分数、颗粒粒径。Objective To optimize the design of the converging-diverging tube liquid-solid two-phase flow heat exchanger,a visual experi-mental platform was constructed.Particle image velocimetry(PIV)was employed to investigate the two-dimensional flow field characteristics within a vertical upward converging-diverging tube liquid-solid two-phase flow heat exchanger.The study ana-lyzed the influence of inlet fluid velocity,particle size,and particle volume fraction on the radial velocity and vorticity of the fluid,aiming to elucidate the mechanisms of enhanced mass and heat transfer in the liquid-solid two-phase flow within the converging-diverging tube.Methods A visual experimental platform was established,utilizing tap water as the circulating liquid medium,spherical acrylic particles as the solid phase material,and quartz glass as the converging-diverging tube structure.Based on the general prin-ciples of particle settling velocity in engineering applications and considering the constraints of experimental conditions,three key parameters were selected,i.e.,inlet fluid velocity,particle size,and particle volume fraction.Each parameter was set at five gradient levels.Two-dimensional PIV technology was employed to systematically investigate the flow field characteristics within a vertical upward converging-diverging tube liquid-solid two-phase flow heat exchanger.The influence of inlet fluid velocity,particle size,and particle volume fraction on the radial velocity and vorticity of the fluid was explored,and the optimal combination of operating conditions was determined.Results and Discussion The increase in the average radial velocity of the liquid-solid two-phase flow indicated enhanced radial fluid motion,which strengthened fluid exchange between different regions and promoted heat and mass transfer among these regions.Within a single pitch of the converging-diverging tube,the radial velocity of the liquid-solid two-phase flow at various radial positions exhibited positive and negative fluctuations as the axial height inc

关 键 词：缩放管 液固两相流 流场特征 粒子图像测速技术 换热器 

分 类 号：TB4[一般工业技术] TK124[动力工程及工程热物理—工程热物理]