摘要
对液滴撞击过热液池的动态过程进行数值模拟,着重关注由液池表面不均匀温度引起的马兰戈尼效应(Marangoni effect)对液池内的流场和温度场演化过程的影响。当乙醇液滴落入过热油池后,液池表面温度随着液滴的靠近而迅速下降,从而在径向上产生很大的温度梯度。由此引发的沿径向向内的Marangoni力会与沿径向向外的蒸汽剪切应力相抗衡,进而在蒸汽层最薄的位置形成一个“热射流”结构。随着时间的推进,占据主导地位的Marangoni力逐渐将“热射流”向内推动,直至在液滴下方形成下沉羽流。此外,随着液池黏度的增加,液池内由表面蒸汽应力引起的流动将被抑制,进而导致界面附近的换热效率大幅下降。
We numerically investigate the dynamic behaviors of a droplet impacting onto the non-volatile superheated liquid pool,and focuse on the influence of the Marangoni effect resulted from the inhomogeneous temperature distribution at the surface of liquid pool.Particularly,the time evolution of the flow field and the temperature field inside the pool during and after the impacting are studied.We find that the pool surface,made of oil,is cooled quickly as the ethanol droplet approaches,and a large temperature gradient is produced along the radial direction.Correspondingly,the Marangoni force directs radially inwards to resist the radial outward vapor stress,and a“jet”like structure is formed at the position where the vapor layer becomes thinnest.As the time advances,the Marangoni force becomes dominant and the“jet”is pushed radially inwards until the rear of the droplet and form the downward plume flow.In addition,as the viscosity of the liquid pool increases,the flow induced by the vapor stress is suppressed which further reduce the heat exchange efficiency near the interface.
作者
赵烁
张杰
倪明玖
ZHAO Shuo;ZHANG Jie;NI Mingjiu(School of Engineering Science,University of Chinese Academy of Sciences,Beijing 100049,China;State Key Laboratory for Strength and Vibration of Mechanical Structures,School of Aerospace,Xi’an Jiaotong University,Xi’an 710049,China)
出处
《中国科学院大学学报(中英文)》
CAS
CSCD
北大核心
2024年第3期289-297,共9页
Journal of University of Chinese Academy of Sciences
基金
国家自然科学基金(51636009,11872296,U1732276)资助。