关键词: 格子Boltzmann方法/
液滴/
液膜
English Abstract
Lattice Boltzmann simulation of the droplet impact onto liquid film
Huang Hu1,Hong Ning2,
Liang Hong3,
Shi Bao-Chang1,4,
Chai Zhen-Hua1
1.School of Mathematics and Statistics, Huazhong University of Science and Technology, Wuhan 430074, China;
2.School of Information and Engineering, Wuchang University of Technology, Wuhan 430223, China;
3.Department of Physics, Hangzhou Dianzi University, Hangzhou 310018, China;
4.State Key Laboratory of Coal Combustion, Huazhong University of Science and Technology, Wuhan 430074, China
Fund Project:Project supported by the National Natural Science Foundation of China (Grant Nos. 51576079, 11272132) and the National Natural Science Foundation of Hubei Province, China (Grant No. 2015CFB440).Received Date:23 November 2015
Accepted Date:28 December 2015
Published Online:05 April 2016
Abstract:The process of the droplet impact onto the liquid film, as one of the basic multiphase problems, is very important in many fields of science and engineering. On the other hand, the problem is also very complicated since there are many parameters that may influence the process of the droplet impact on the liquid film. To clearly understand the physical phenomena appearing in the process droplet impact on the liquid film, a parametric study on this problem is conduced based on a recently developed lattice Boltzmann method in which a lattice Boltzmann model is used to solve the Navier-Stokes equations, and the other is adopted to solve the Cahn-Hilliard equation that is used to depict the interface between different phases. In this paper, we mainly focus on the effects of the Reynolds number (Re), the Weber number (We), the relative thickness of film (h) and the surface tension () on the dynamic behavior of interface between different phases, and the velocity and pressure fields are also presented. It is found that with the increase of Re and We, the phenomena of crown and entrainment can be observed obviously during the process of droplet impact onto the liquid film, and the radius of the crown seems not dependent on the We and Re where the relative thickness of film and surface tension are fixed to be 0.5 and 0.003. However, when Re becomes much larger, the splashing phenomenon is produced, and the small droplets caused by the splashing can fall and then impact onto the liquid film again. We also find that if the relative thickness of film is small, the surface tension, Re and We are set to be 0.003, 480 and 500, the film can break up during the process of the droplet impact onto the liquid film, while with the increase of relative thickness, although more liquid are induced in the splashing process, the film cant break up. In addition, with the increase of surface tension, the resistance which prevents the change of interface becomes large, and thus the change of interface is not large when the droplet impacts onto liquid film, as expected. And finally, a quantitative study on the relation between the radius of crown (formed by droplet impact onto liquid film) and the time is also performed, and the expression r/(2R) Ut/(2R) where the parameter is about 1.0 and is also independent of We and Re, can be used to describe the relation.
Keywords: lattice Boltzmann method/
droplet/
liquid film
