Modeling And Simulation Of Blocking Process In Microreactor

Microreactors have been widely used in the field of microchemicals and medicine.The microchannel blockage problem is a common problem in microreactor failure.The reaction efficiency will be decreased and the yield production cost will be greatly increased with the occurring of the blockage.In the research,firstly,using the population balance model（PBM）and the classical precipitation theory,the concept of mixed scale is introduced.The BaSO₄（Barium sulfate）particles（Na₂SO₄+BaCl₂）are used as the reaction example in the microchannel.The generated reaction background modeled the nucleation,growth and aggregation process of the blockage generated by the reaction in the microchannel,simulated the formation process of partial blockage,and applied the model to quantitatively analyze the initial concentration,mixing scale,etc.The effect of factors on the number density of blockage and the size of the blockage.At the same time,according to the force of the blockage in the microchannel,the precipitation process of the blockage in the microchannel is simulated.Considering the slight fluctuation of the concentration in the actual reaction,the minimum flow velocity V_offff required to discharge the blockage into the microchannel is defined,and an optimization problem that considers the microchannel energy consumption and flow stability is proposed.At this condition,the accumulation of the blockage can be avoided.The power consumption and controllability of the microreactor can be guaranteed.Furthermore,the inertial lift of the blockage in the microchannel and the lateral migration force through the secondary flow under partial blockage conditions are analyzed.By introducing inertial aggregation and Dean secondary flow,the microchannel with expansion and contraction structure unit is optimized,and the optimal design of the microchannel structure is used to remove the blockage.Finally,a simulation model of CFD（Computational Fluid Dynamics）is established to compare the effect of the expansion and contraction structure and the removal of the blockage in the straight microchannel.The results show that compared with the straight microchannel,the separation efficiency of the expansion and contraction structure microchannel improves the blockage by 340%.It is proved that the expansion and contraction structure can effectively separate the blockage in the solution,realize the separation and elimination of the blockage,and prevent the full obstruction in the microchannel due to the precipitation of the blockage.