CFD Simulation And Experimental Research On Hydrodynamics In Bubble Column

In this thesis, we investigate the liquid flow in countercurrent bubble column through the method of CFD(computational fluid dynamics), and present a correlation formula to predict the velocity distribution of liquid phase with the improved quasi single-fluid model , and have studied the mixing characteristic by using back mixing model to regress the RTD curves which are attained in CFD simulation, in order to compare with experimental work.The improved quasi single-fluid model is found not only simple in the liquid flow simulation of bubble column, but also it has higher computation precision. In the fully developed flow region ,the liquid axial velocity is mostly devoted by fluid velocity, gas velocity, column height and radial position. In this paper, three assumptions for gas velocity were put forward, then correlation formulas for the axial velocity of liquid including the parameters were achieved. Compared with the experiments, it indicated that the radial parabola assumption for gas velocity can be used more correctly to calculate liquid axial velocity.In the experiment, the hot-film anemometry was applied to the countercurrent bubble column and local measurements of gas hold-up were obtained. Backflow region is also found to have the same characteristic in experiment as that found in the simulation. The gas hold-up value is lower in the center of the column and higher near the wall. And in each section it arise from the center to the wall, and at the same radial position arise from bottom to top.Based on the formed research on the cells of structured packing, a systemic simulation research on liquid flow and the mixing characteristic of the cells at different liquid velocity is carried out. And we find the liquid velocity distribution and the mixing coefficients of liquid are affected by superficial velocity of liquid in some sense.