Studies of Dynamics Multiphase Flow of Bubble and Water System using Computational Fluid Dynamics Method and Electrical Capacitance Volume Tomography (ECVT) Imaging Technique
Sutarto, MS Thesis, Dept. of Physics, University of Indonesia, 2011
A Series of transient simulations for multiphase flow system had been done for a single bubble rising through stagnant water, a single water droplet falling down to a liquid, and in bubble column reactor. Experimental studies also performed to clarify the simulation results using Electrical 4D Capacitance Volume Tomography (ECVT) with 16 Electrodes. Navier–Stokes was employed to simulate the single bubble rising and water droplet system. Phase field model is used to track the interface of the two phases but the bubble shape’s deformation shows unnatural behavior indicating that the phase field method could not hold the bubble–water interface. Moreover, the phase field method could not prevent the mass loss of the gas phase in quite significant amount. Different series of simulations had been done to clarify the problem by adding the so–called effective bubble’s viscosity constant. 4D ECVT experimental result shows good agreement with the simulations results. The unnatural behavior of the bubble rising maybe caused by an interface controlling parameter and the surface tension which is directly connected to the surface tension coefficient. In water droplet system, using standard physical properties of air and water, the phase field method shows an excellent performance. It is also found that water droplet system has laminar behavior rather than turbulence. Transient simulation for the bubble column using k– turbulence model revealed water circulation and coherent bubble plume flows. Qualitatively, the simulations of the bubble column had shown well agreement with experimental data.
Keywords: multiphase flow, bubble, bubble column, 4D ECVT, laminar, k– turbulence, effective viscocity, phase field method