Modeling And Visualization Of Coalescence Process Of Smooth Bubble Surface

Bubble phenomenon can be seen everywhere in life,and it also plays an important role in the fields of chemistry,food,environment and animation production.Coalescence is one of the bubble movement behaviors,but up to now there are few studies on the visualization of the bubbles' coalescence process in liquid.Therefore,the purpose of this paper is to visually study the coalescence behavior of multiple bubbles in liquid at different initial relative positions,and to obtain the shape change of bubbles during coalescence,which can be used to predict the change of gas-liquid two-phase contact area,and also provide reference for the design and optimization of gas-liquid contact equipment.The main work is as follows:(1)On the basis of previous studies on bubble coalescence,a method combining edge detection and curve fitting is proposed to visualize the coalescence process of parallel bubble pairs with equal and unequal sizes.In this method,the problem of unsmooth points between the segmented curves is secondary-processed by limiting the continuity condition on the segmented points,that is,the values of the functions and the left and right derivatives are equal correspondingly,to guarantee that the fitted bubble contour tends to be smooth.(2)In order to simulate the continuous change of the whole process of bubble coalescence,the transition function between adjacent moments is designed after obtaining the contour equation of each moment.Then the 3D visualization is obtained through the rotation of the 2D graph.(3)On the basis of fitting the bubble pairs of piecewise polynomial curves,closed B-spline fitting is used to realize the fast and efficient bubble clustering and fitting.The simulation results show the coalescence behaviors of the initial radius and spacing of different bubbles,in different angles,and the coalescence behavior of different arrangement of bubbles in the rising process.