Study On Flow Field Energy And Mixing Characteristics Of Two-component Impinging Stream Reactor

The study of the flow field characteristics of the impinging stream reactor is one of the key points in the study of turbulent fundamental theory.The study of the flow characteristics and mixing characteristics of the internal flow field is helpful for people to further understand the impact flow and is crucial for its engineering application.In this paper,the traditional single-layer impinging stream reactor can only achieve the single impact of material,and the two-component layer impinging stream reactor test platform is designed and constructed.Two-dimensional high-speed particle image velocimetry（TR-PIV）technology and plane laser induction are used.Fluorescence（PLIF）technique was used to study the flow field energy distribution and mixing characteristics of the nozzles with the same jet motion conditions in the two-component impinging stream reactor under the same asymmetric impact conditions.The influence of different working conditions on the flow field energy and mixing time,and the combination of the flow field energy and the mixing rate.The main work of the full text is as follows:The TR-PIV and PLIF techniques were used to measure the velocity field and concentration field in the reactor,and the instantaneous velocity field,time-average velocity field,energy field and mixing characteristics in the reactor were obtained.The POD analysis method was used to measure the two-dimensional transient.The time series of state velocity field is decomposed and reconstructed,and the large-scale structure of the flow field is extracted.The main energy of the flow field is concentrated in the first-order mode,so that the first-order modal energy is used as a measure of symmetry and no The energy distribution law of the symmetric flow field was analyzed.Under symmetrical impact:the operating parameters of the upper and lower nozzles are fixed at the same time,and the influence of single variable Re,nozzle diameter or nozzle spacing on the energy distribution of the flow field is investigated.It is concluded that the first-order modal energy of the flow field increases with the increase of Re.With the increase of nozzle diameter and nozzle spacing,the trend is first increased and then decreased,and the mixing behavior is consistent with it.Based on the preliminary understanding of the flow field energy,the flow field（asymmetric）stagnation point is further investigated by changing the nozzle diameter,controlling the Reynolds number and the nozzle spacing to change the axial and radial impact stagnation position changes of the two layers of fluid.The offset of the upper and lower axial impact stagnation points,radial impact stagnation points on the overall flow field energy and mixing.The results show that the asymmetric flow field energy is always larger than the symmetric flow field,while the uniform mixing rate is lower than the symmetric flow field.For the energy,the same as the nozzle diameter,the upper and lower left and right jets have different Reynolds number,the asymmetric flow field energy is always larger than the symmetrical flow field,the nozzle diameter d=10mm is the best working condition,and the flow field energy on the same side of the stagnation point is less than the stagnation point.At different intervals,the flow field energy increases with the increase of the Reynolds number of the nozzle jet,and decreases with the increase of the nozzle spacing.When the nozzle diameter is different,the flow field energy increases with the increase of the diameter ratio K.For mixing,under the different jet Reynolds number of the same diameter,the lower tracer（stationary point）is left（full development）can promote the flow field mixing;at different diameters,the flow field stagnation point mixing time is higher than the stagnation point In the same kind of impact mode,K₁ mixes faster than K₂.Therefore,this asymmetry of the jet is beneficial to increase the flow field energy,and the initial development of the tracer is beneficial to the flow field mixing.