抄録
The process of bubbles sliding along a wall under the effect of buoyancy and gravitation in vertical rectangular channels is studied using the VOF model in FLUENT along with the three-dimensional numerical simulation method. The impact of bubble size, flow field and other factors on the bubble behavior was studied considering the effects of surface tension, fluid viscosity and contact angle. The numerical simulation was verified using empirical data. The empirical data were collected using high-speed photography technique and post-processing software to capture the bubble slip process. The numerical simulation proved to be very close to the results obtained from the experiment. The simulation results showed that the bubble is half ellipsoid while sliding along the wall and its size fluctuates in all directions. The slip velocity becomes smaller with the increasing size of bubble diameter, which shows that the increasing rate of resistance is faster than that of flotation in the vertical direction. The system pressure has little impact on slip velocity and the shape of the bubble. Fluid viscosity mainly affects the bubble shape; the higher the fluid viscosity, the more stable the bubble. Surface tension mainly affects the slip velocity of the bubble and higher surface tension causes the bubble to become spherical. The larger the surface tension, the larger bubble slip velocity.
