Numerical Study Of The Gas-liquid Two-phase Taylor Flow In Micro-channel

The micro-reactor has been widely used which made the Taylor in microchannelgas-liquid two-phase flow become a research focus in recent years, the Chemicalreaction could carry out in the microchannel, it plays the role of strengthening theprocess. The characteristics of Taylor flow is reduce the back mixing in channel, thelager phase interface could promote gas-liquid mass transfer and heat transferbetween the two-phases. The length of bubble and liquid column not only affect thechannel interface mass transfer conditions but also could affect the flow in channel,specific surface area represents the size of mass transfer interface, the lager ofinterface the better of mass transfer. How to get longer and high frequency bubblesand keep the Taylor flows in microchannel, those are the basic ways to speed up thechemical process in microchannel. So it is very necessary to research the Taylor flowin microchannel.This article adopts the method of computational fluid dynamics (CFD),respectively change the equivalent diameter, liquid fluid viscosity, surface tensioncoefficient and so on, and inspect the influence to Taylor flow. Simulation show that:the length of bubbles and liquid column become shorter as the decrease of theequivalent diameter and the increase of liquid viscosity, surface tension coefficienthas little influence to the length of the bubbles and liquid column. Based on theresearch of the influence factors, and the data in the simulation, we get thecorrelations for this model which could predict the length of bubbles and liquidcolumn, the correlations be verified is reasonable.When the fluid flow is unsteady, keep the gas liquid velocity change over time.we got the detailed process of Taylor flow become churn flow or annular flow and theprocess pressure figures. On the basis of drawing the transition line of Taylor flow.The results show that: under the fixed liquid flow rate, the transition line of Taylorflow become slug-annular flow or churn flow tend to the direction of the gas phase flow velocity as the the decrease of the equivalent diameter, the increase of liquidviscosity and surface tension coefficient.Through the numerical simulation of gas-liquid two-phase Taylor flow, we foundthat micro-reactor should reduce the equivalent diameter to make the Taylor not easyto change, reduce the viscosity of liquid phase to keep the bubble and liquid columndistribution uniform, so the micro-reactor could have optimized mass and heattransfer effects.