CFD Simulation And Experimental Study On Micromixing Of T-type Microreactor

Microreactors have showed excellent heat and mass transfer performance and are considered as one of the main ways to achieve process intensification and continuous production.The conversion and selectivity of chemical reactions in the liquid phase may depend significantly on the mixing process.Mixing has a huge impact in reactions such as polymerization,crystallization and precipitation.Mixing efficiency is an important performance index of chemical reactors.In this work,a simple T-shaped microreactor was used to facilitate fundamental studies of reactor micromixing.CFD simulations combined with experiments were used to study the fluid flow and mixing performance in the reactor,and the effects of operating parameters and reactor parameters on the mixing performance were investigated.The main contents and finding are as follows:The fluid flow inside the T-shaped microreactor was simulated and studied to obtain the velocity distribution and turbulent kinetic energy distribution inside the reactor.The physical mixing process of water and ethanol was then studied and the mixing intensity was used to quantify the mixing performance of the microchannel reactor,and the effects of Reynolds number(Re),tube inner diameter(d)and inlet volumetric flow ratio(R)on the mixing performance were investigated.The mixing intensity can be used to determine the end point of mixing process and to calculate the mixing time,which was obtained within the range between 2 and 50 ms.The effects of Reynolds number and tube diameter on the mixing performance of the reactor were studied both numerically and experimentally using the Villermaux/Dushman method.As the Reynolds number increased,the mixing performance was firstly improved significantly and then maintained stable;at the same Reynolds number,a smaller tube diameter benefited the mixing,and the optimal inlet volumetric flow ratio was 1.The species concentrations of the Villermaux/Dushman reaction in the reactor were also investigated.The results showed that the Villermaux/Dushman reactions were completed before the solution was mixed uniformly,and the subsequent reactor structure could not further affect the experimental results after the reaction was finished.Changing the initial hydrogen ion concentration can only adjust the reaction completion time in a small range.The Villermaux/Dushman system is difficult to match the reaction time with the reactor mixing time and is not suitable for asymmetric flow conditions,so the practical application of the system is narrower than assumed.In CFD simulations,the mixing intensity can be used to study the mixing performance of the reactor,which can save the simulation efforts significantly without involving the reaction processes.