Numerical Simulation Study Of Residence Time Distribution In An Oscillatory Flow Reactor

Great interest has been input on Oscillatory Flow Reactors (OFR), which has good performance in momentum, heat, and mass transfer. The transfer processes in an OFR can be well controlled by changing the frequency and amplitude of fluid oscillation. Many potential applications of OFR in chemical engineering have been explored, such as particle suspension and separation, flocculation, filter, chemical reactors, separation processes in bioengineering and pharmaceutical engineering.In this thesis, CFD method was used to simulate the Residence Time Distribution (RTD) in an OFR. The influence of some main factors on RTD, such as oscillatory Reynolds number (Red), number of cells in an OFR, and net flow rate, were studied.Our work focused on computating the residence time of tracing particles in three-dimensional laminar flow with a constant net flow rate in an OFR. The RTD curves in different Reo were obtained through post-treatment for four-cell, eight-cell OFRs and baffled and non-baffled tube reactors. Based on the shape RTD curves, a kind of phenomenological models of mixing patterns was built up.It's the first time to implememt the simulation of RTD in three-dimensional OFR flow field, and to obtain RTD curves with 1000 tracing particles. Referring to the results with 4 and 8 cells, the phenomenological models of 4 and 8 CSTRs in series with inter-stage back-mixing were used to carry out a comparitive study. By optimal reconciliation of the back-mixing ratio, the phenomenological models can describe RTD figures of OFR quite well. The adjustable model parameter, back-mixing ratio, varied obviously with Reo and number of cells changing.The work presented here will be very helpful to the following research. Base on the result of numerical simulation of RTD in OFR, futher simulation study on chemical reaction process in OFR can be carried out.