撞击流急冷箱流动混合特性研究

Flow mixing characteristics in impingement quench box

撞击流过程强化技术在能源化工、生物材料等行业都有广泛的应用价值。利用数值模拟技术,对不同工况条件下加氢反应器急冷箱内的流动性能及混合效果进行研究。结果表明:操作负荷的变化对液相降温性能的影响同时存在混合强度和混合时间之间的竞争。当操作负荷减小时,气液相速度减小,导流板使流体折流产生湍流,气液相之间相互卷吸缠绕,形成折叠涡旋,最终形成气液相混合缠绕的流体界面,气液相混合程度会相对增大,即高温液相与低温冷氢气间的热交换程度相对增大;当操作负荷增加时,气液对撞速度也增大,气液相对撞强度增大,混合箱内部以撞击流强化为主,形成相互撞击的层状流体接触界面,增加了2股反应物间的接触面积,混合程度显著提升。

The impinging stream process intensification technology has a wide range of application value in the energy,chemical industry,biomaterials and other industries.Computer simulation technology was used to study the flow performance and mixing effect in the quench box of the hydrogenation reactor under different working conditions.The results show that the change of operating load has the opposite effect on mixing intensity and mixing time,and has an impact on the cooling performance of the liquid phase.When the operating load decreases,the velocity of the gas phase and liquid phase decreases,and the baffle makes the fluid flow turbulence.The gas phase and liquid phase entangle with each other to form a vortex,and finally form a fluid interface where the gas and liquid phases are mixed,which increases the mixing time.The degree of gas-liquid mixing will relatively increase,so the degree of heat exchange between the high-temperature liquid phase and the low-temperature cold hydrogen will also increase relatively.When the operating load increases,the gas-liquid collision speed increases,and the collision intensity increases.The interior of the mixing box is dominated by impingement,forming a layered fluid contact interface that collides with each other,increasing the interface contact area between the reactants,and the mixing degree is significantly improved.