Study On The Characteristics Of Fluid Mixing Process In Millimeter Channel

Liquid-liquid mixing process is common in industrial production,and it directly affects the subsequent reaction process and even the distribution of products.T-channel is a simple micro-mixing device.In this study,the velocity distribution and concentration distribution before and after the impact point of T-channel were investigated by PIV and mixing experiments.Then ANSYS fluent is used to carry out the corresponding numerical calculation,and the simulation results are compared with the experimental results to verify the reliability of the simulation method.Then the new channels are studied by numerical simulation,and the mixing effect is compared with the traditional T-channel.Finally,the influence of the structural variables of the new channel T2 on the mixing quality is investigated.By changing the inlet velocity,the experimental study and numerical calculation of the flow and mixing in five different Reynolds numbers of T-channel are carried out.From the contours of velocity and concentration distribution before and after meet,and the quantitative comparison of concentration and velocity at y=1 mm and y=4 mm,and the judgment of dimensionless number K on fluid flow pattern in the references,it is proved that the simulation method is available.With the increase of Reynolds number,the traditional T-channel experiences separated flow,vortex flow and engulfment flow in turn,and the mixing effect is getting better.In order to make use of vortex and increase the contact area of separated flow,a cross baffle was added at the inlet of the channel and flow stream crosses into the channel.Thus,a new channel T1 is constructed.At the same time,the flow of the engulfment flow was studied,and two intersecting baffles were added at the outlet of the channel in order to cause the fluid to rotate,and a new channel T2 was constructed.By comparing the flow patterns in the three channels and the concentration distribution at different exit positions,and analyzing the mixing index,mixing time and pressure drop quantitatively,it is concluded that T2 channel can achieve millisecond rapid mixing.By changing the baffle height and tilt angle in channel T2,the influence of baffle height and tilt angle on mixing effect and pressure drop was analyzed.After weighing the mixing mass and pressure drop,the size combination is B0.8D45 in the separated flow state;B0.8D30 or B0.6D30 in the vortex flow;B0.8D30 or B0.4D15 in the engulfment flow.