Numerical Simulation of Concentration Field on Liquid Side around Bubble during Rising and Coalescing Process in Non-Newtonian Fluid

根据 Navier-Stockes 方程和传送对流散开方程，与表面紧张和穿入模型，结合了在水泡和周围的非牛顿的液体之间的时刻和集体转移的方程被建立。从从进周围的液体的一个人工地固定的水泡的 1.0 公里直径和集体转移的一张在水下的嘴的一个单个水泡的形成被体积模仿 -- 液体(VOF ) 方法。在模拟结果和试验性的数据之间的好同意证实了数字方法的有效性。而且，在升起附近的集中分发起泡在砍变瘦非牛顿的液体被模仿。当有低于 2.0 的水泡变丑率的一个单个椭圆体的水泡的过程升起时，集中分发是一在水泡的家单个尾巴醒来，但是当水泡变丑率比 2.0 大时，它是分数维的。为追上二个同轴的升起水泡，在二个水泡之间的集中分发区域逐渐地拓宽然后结合发生。集中分发的分叉出现在结果的水泡的尾部。

On the basis of Navier-Stockes equation and convection-diffusion equation, combined with surface tension and penetration models, the equations of moment and mass transfer between bubble and the ambient non-Newtonian liquid were established. The formation of a single bubble from a submersed nozzle of 1.0 mm diameter and the mass transfer from an artificially fixed bubble into the ambient liquid were simulated by the volume-of-fluid （VOF） method. Good agreement between simulation results and experimental data confirmed the validity of the numerical method. Furthermore, the concentration distribution around rising bubbles in shear thinning non-Newtonian fluid was simulated. When the process of a single ellipsoidal bubble with the bubble deformation rate below 2.0 rises, the concentration distribution is a single-tail in the bubble＇s wake, but it is fractal when thebubble deformation rate is greater than 2.0. For the overtaking of two in-line rising bubbles, the concentration distribution area between two bubbles broadens gradually and then coalescence occurs. The bifurcation of concentration distribution appears in the rear of the resultant bubble.