Numerical Modeling Of Bubble Column With Vertical Internals

The bubble column reactors were widely used in the fields like coal chemical industry, petrochemical engineering, biological engineering and environmental engineering for the advantages of good heat and mass transfer performance, simple structure and low cost. The Euler-Euler method was applied for the simulation of bubble column with vertical internals in this paper. The preferable turbulent closure model for the simulation of bubble column with internals was confirmed, and other interaction closure models were studied in the vertical upflow. The following subjects were included.The present PBM models were critically reviewed and numerically analyzed, the coupled models was proposed which was able to describe the bubble coalescence and breakup taking into account more factors of collision induced coalescence, and the resulted daughter bubble size distribution showed a M-type based on the balance of the surface energy and pressure energy. The coupled model was applied in the simulation of the Kukarni experiment, the result showed that the model can well predict the bubble size distributions. The coupled model was further applied in the three-dimensional simulations of a lab-scale bubble column with vertical internals. It was confirmed that the anisotropic RSM turbulent model was preferable in the simulation of bubble column with internals, and the predicted results of axil liquid velocity, gas holdup and turbulent kinetic energy agreed with the literature data. The results showed that the turbulent kinetic energy and turbulent dissipation rate reduced and the bubble size became larger when the internals were added into the bubble column.The turbulent closure models were investigated for the simulation of a vertical upflow bubbly flow. The results showed that the lift force was dominant among the radial forces, and turbulent dissipation force was not strong enough to overcome the lift force. Meanwhile, the wall peak of gas holdup near the wall in the experiment can be realized when the wall lubrication force was taken into account. The influence of bubble induced turbulence (BIT) on the simulation results of gas-liquid two phase flow was significant, especially on the turbulent kinetic energy and turbulent dissipation rate, which can provide the references for the PBM. Troshko model prevailed over Sato model in describing the effect of bubble induced turbulence; The effect of BIT is significant at a high superficial velocity. In contrast, the effect of BIT can be negligible at a low superficial gas velocity due to the little contribution of gas to liquid turbulence when gas holdup is low.