四旋静态混合器内气泡聚并破碎行为的CFD-PBM模拟OA

The bubble coalescence and breakup processes significantly influence the mixing and mass transfer efficiency of static mixers by changing the bubble size distribution.The bubble coalescence and breakup behaviors in the static mixer with four spiral leaves(FKSM)was studied by CFD-PBM coupling method.Based on the experimental data,the prediction results of eight model combinations on the dimensionless Sauter mean diameter(d32/D0)were analyzed.When the Reynolds number(Re)was 18200 and the dispersed phase volume fraction was 0.05,the average deviation between the d32/D0 predicted by Luo-Lehr model and the experimental value was 2.68%compared with other coalescence and breakup models.Furthermore,the variation law of gas holdup and bubble size distribution was revealed,and the influences of the element aspect ratio(Ar)and dimensionless spacing ratio(Gp/D0)on the mixing characteristics were also discussed.The results demonstrated that the radial gas holdup and bubble number density in FKSM showed a bimodal distribution trend.When the Ar was 1.5,the swirling element could optimize the flow path of fluids and effectively promote bubble breakup,and FKSM had better gas-liquid dispersive mixing performance.In terms of energy consumption and mass transfer characteristics,Gp/D0=0.25 performed well.