Research On The Mixing And Reaction Process Of Top-blown Immersion Stirred Liquid Phase Based On PLIF Technology

In order to make an intuitive visual measurement of the top blown immersion agitation,the liquid mixing process and liquid reaction process in top submerged blow stirred was studied by planar laser induced fluorescence?PLIF?technology.In the study of the liquid mixing process,the two-dimensional mixing process and mixing effect of the liquid phase were quantitatively evaluated by the fluorescence intensity of the fluorescent tracer?sodium fluorescein?was proportional to the concentration combination with the plane mixing uniformity U?t?and the mixing time t_95?m?.In the study of the liquid reaction process,the linear relationship between the fluorescence intensity of the fluorescent tracer?sodium fluorescein?and the fluorescence quencher(Fe³⁺)concentration,combined with the reactivity??t?and the reaction time t_95?r?The liquid phase two-dimensional reaction process and reaction effects were evaluated.The results show that:?1?The mixing process of liquid phase is divided into three periods:initial stage of mixing?0.9<U<1?,medium of mixing?0.1<U<0.9?and end of mixing?0<U<0.1?.Increasing the air flow rate Q and increasing the immersion depth L of the spray gun in the experiment can accelerate the liquid phase mixing and shorten the mixing time.There is a local mixing difference in the liquid phase.Increasing the air flow rate in the experiment can reduce the local mixing difference of the liquid phase from 8.2%to 3.7%.Increasing the immersion depth of the spray gun can reduce the local mixing difference of the liquid phase from 8.2%to 1.9%.When L=3 cm,the lower the horizontal line,the longer the reaction time.The mixing time of the fluorescent tracer at the bottom injection?26.08s?is much larger than the mixing time at the top injection?15.36s?when L=3cm,and the mixing time?9.52?of the fluorescent tracer at the bottom injection is close to the mixing time?9.44 s?at the top injection when L=11cm.In addition,the tendency of the horizontal line mixing time of the fluorescer at the bottom injection is consistent with that at the time of the top injection.?2?Increasing the air flow rate and increasing the immersion depth of the spray gun in the experiment can accelerate the diffusion speed of Fe³⁺,accelerate the liquid phase reaction,and shorten the reaction time.There is also a local reaction difference in the liquid phase.the maximum monitoring time?26.02s?exceeds the minimum?20.34s?by 27.9%when L=3cm,Q=0.2L·min^-1,there is no obvious trend in the change of horizontal line reaction time.The fluidity at the bottom of the reactor is poor when the immersion depth of the spray gun is shallow,and Fe³⁺is difficult to diffuse after the bottom injection,so that the reaction time is much larger than the top injection.The reaction time of the bottom injection?29.32s?exceeded the reaction time?23.04s?at the top injection by 27.3%when L=3cm,Q=0.2L·min^-1.the reaction time of the bottom injection exceeded the reaction time of the top injection by 19.7%when L=3cm,Q=0.6L·min^-1.The reaction time of the two injection points is nearly uniform when L=9,11 cm.The change in the initial volume of Fe³⁺had no significant effect on the reaction time.Increasing the initial concentration of Fe³⁺can shorten the reaction time.The research content of this paper has guiding significance for how the top-blown immersion agitation process in the actual production process can improve the mixing reaction efficiency,shorten the production time.