Mixing In A Soft-elastic Reactor(SER):A Simulation Study

Traditional chemical reactors are usually hard and made by rigid materials,vessel walls can not actively join in the mixing and reaction inside the container,therefore,the mixing of material in the reactors have to rely on auxiliary devices,i.e.agitators,static mixers etc.However,there are obvious limitations for the conventional mixing methods,especially for mixing highly viscous fluid at relatively low Reynolds numbers(Re).Moreover,because the walls of traditional rigid reactors are stationary,it is prone to fouling on the inner walls for materials due to adhesion and deposition.Inspired by the animal upper digestion tract,a strategy of developing SER for potential industrial usage has evolved which is under the framework of bioinspired chemical engineering.SER was constructed by silicone rubber with good transparency,toughness and elasticity,the periodic movement of the wall is realized under drive system.SER mainly promote mixing through the movement of its elastic wall,which can also prevent the fouling on the reactor wall.The mechanisms of SER are,however,not yet fully understood.Here we present a CFD study on the mixing behavior of SER to reveal the SER characteristics.For simplicity and also for gaining more precise understanding of a SER,two-dimensional situations are analyzed numerically with a successful implementation of a moving mesh method in ANSYS Fluent.The approach allows versatile movement of the reactor wall to be effectively simulated.Systematic investigations were then carried out to investigate two wall motion modes.With simulated dye injection in glycerin,the effects of such motion modes have been demonstrated through tracking the evolution of the flow fields and analyzing the mixing time.The results show that high viscosity fluid mixing can be realized in SER and the mixing behavior can be effectively controlled by the tracer injection locations,the frequency and degree of boundary movement.This way suggests rooms for potential improvement of SER by devising different wall movements.On the basis of the simulation of SER,we further developed numerical models of elliptical ball-shaped soft-elastic reactor,human stomach and small intestine to investigate the flow filed information in the gastrointestinal tract.