Dynamics and heat transfer of a hollow droplet impact on a wetted solid surface
Dynamics and heat transfer of a hollow droplet impact on a wetted solid surface
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DOI：
10.1016/j.ijheatmasstransfer.2018.02.017
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发表时间：
2018-07-01
影响因子：
5.2
通讯作者：
Liu, Yusen
中科院分区：
文献类型：
--
作者：
Li, Dashu;Duan, Xili;Liu, Yusen
建立了基于水平集和分数体积（CLSVOF）耦合方法的数值模型，研究了空心液滴撞击湿固体表面的动力学和传热过程。数值结果表明，空心液滴与连续致密液滴的碰撞行为不同。中空液滴的独特流动特征之一是中心反射流，这在连续的致密液滴中是不存在的。压力分布分析表明，中心反喷主要是由于空心液滴在冲击和扩散过程中内部的压力梯度造成的。仿真结果还表明，空心液滴的冲击速度决定了其扩散系数、无因次扩散边缘射流高度和中心反射流高度，三者均成正相关关系。分析了冲击液滴与表面之间复杂的瞬态传热过程。平均热流密度随冲击速度的增大而增大。空心液滴撞击时的总换热量低于连续致密液滴撞击时的总换热量。这些结果有助于更好地理解空心液滴在湿表面上的撞击和传热。(C) 2018 Elsevier Ltd.版权所有。
A numerical model based on the coupled level set and volume of fraction (CLSVOF) method is developed to investigate dynamics of a hollow droplet impacting on a wetted solid surface and the associated heat transfer process. Numerical results show different impact behaviors of the hollow droplet as compared to a continuous dense droplet. One of the distinctive flow features of the hollow droplet is a central counter jet, which is not present in continuous dense droplets. Analysis of pressure distribution indicates that the central counter jet is mainly due to the pressure gradient inside the hollow droplet during the impact and spreading. Simulation results also show that the impact velocity of the hollow droplet determines its spread factor, dimensionless spreading edge-jet height and central counter-jet height, all with positive relations. The complicated transient heat transfer between the impacting droplet and the surface was analyzed. The average heat flux increases with higher impact velocity. Overall heat transfer during hollow droplet impact is found to be lower than that during continuous dense droplet impact. These results provide better understanding of hollow droplet impingement and heat transfer on wetted surfaces. (C) 2018 Elsevier Ltd. All rights reserved.