撞击速度对连续液滴撞击热圆柱壁面局部传热特性影响的实验  

Experiment on the effect of impact velocities on the local heat transfer characteristics for successive droplets impacting on heated cylindrical surface

作　　者：罗佳[1,2] 吴双应[1,2] 肖兰[1,2] 周世耀 陈志莉 LUO Jia;WU Shuangying;XIAO Lan;ZHOU Shiyao;CHEN Zhili(Key Laboratory of Low-grade Energy Utilization Technologies and Systems,Ministry of Education,Chongqing University,Chongqing 400044,China;School of Energy and Power Engineering,Chongqing University,Chongqing 400044,China;College of Environmental Science and Engineering,Guilin University of Technology,Guilin 541006,Guangxi,China)

机构地区：[1]重庆大学低品位能源利用技术及系统教育部重点实验室,重庆400044 [2]重庆大学能源与动力工程学院,重庆400044 [3]桂林理工大学环境科学与工程学院,广西桂林541006

出　　处：《化工学报》2022年第7期2944-2951,共8页CIESC Journal

基　　金：国家自然科学基金项目(51966003);广西自然科学基金重点项目(2018GXNSFDA050004);中央高校基本科研业务费专项资金项目(2018CDXYDL0001)。

摘　　要：借助高速摄像机捕获连续液滴撞击热圆柱壁面后的动力学行为,通过直接测试与数值计算方法相结合,获得了不同撞击速度下沿周向和轴向的局部对流传热特性。结果表明,当液滴撞击速度较小,液膜未发生飞溅时,由于圆柱面的各向异性,沿轴向的对流传热系数单调减小,而沿周向,对流传热系数先减小后略有增大;根据对流传热系数沿周向的变化,将圆周划分为撞击区域、热扩散区域和尾部脱离区域;增大液滴撞击速度主要提高撞击区域和热扩散区域的对流传热系数,而对尾部脱离区域对流传热系数的影响并不明显。当液滴撞击速度超过某一临界值(在本文的实验条件下约为1.53 m/s)时,液膜发生飞溅,此时继续增大撞击速度,壁温的降低不再明显。With the help of high-speed camera,the hydrodynamics of successive droplets impacting on heated cylindrical surface were captured.Under different impact velocities,the local convective heat transfer characteristics along the circumferential and axial directions were obtained by combining the directly measured experimental data with numerical calculation method.The results show that,when the droplet impact velocity is small and liquid film does not splash,due to the anisotropy of cylindrical surface,the convective heat transfer coefficient monotonically decreases in the axis,while in the circumference,the convective heat transfer coefficient firstly decreases and then augments slightly.According to the change of convective heat trasnfer coefficient along the circumference direction,the circumference is divided into impingement zone,heat diffusion zone and tail detachment zone.The improvement of convective heat transfer coefficient by increasing the droplets impact velocity is mainly reflected in the impingement and heat diffusion zones,but not obvious in the tail detachment zone.When the droplet impact velocity exceeds a certain critical value(about 1.53 m/s under the current experimental condition),the liquid film will splash.If continuously increasing impact velocity,the reduction of wall temperature is no longer obvious.

关 键 词：流体动力学 传热 对流 热圆柱壁面 撞击速度 液膜飞溅 

分 类 号：TK121[动力工程及工程热物理—工程热物理]