高入口浓度下PV型旋风分离器的分离效率计算

基于Muschelknautz 分离模型,以PV型旋风分离器为对象,针对高入口浓度的分离效率的计算,将旋风分离器分离空间的气固分离过程划分为2个区域,提出了串级分离模型。当入口浓度大于临界入口浓度时,旋风分离器内有器壁附近的颗粒支配区和中心区域的气体支配区。颗粒支配区内颗粒速度大于气体速度,颗粒夹带气体沿器壁螺旋下行进入灰斗被全部捕集,形成了颗粒的一级分离;气体支配区内气体速度大于颗粒速度,气体携带颗粒做旋转运动进行离心分离过程,形成了颗粒的二级分离。旋风分离器总的气固分离过程是一级分离和二级分离的叠加。通过高入口浓度的实验对串级分离模型进行了验证,基于串级分离模型给出的PV型旋风分离器的分离效率与实测值较吻合。研究表明旋风分离器临界入口浓度对总效率的计算影响较大。串级分离计算模型包含了结构参数和气、固相物性等参数,具有很好的通用性,可以满足PV型旋风分离器的工程计算和设计要求。

A new collection efficiency model for PV cyclone under high inlet solids loading

A new collection efficiency model for PV cyclones under high inlet solids loading is proposed based on the Muschelknautz model.The separation space is divided into two regions,particle controlling region near the wall and gas controlling region in the center.The tandem separation model is used for the first and second separation processes of the cyclone operated under high inlet solids loading.When the inlet concentration is higher than the critical concentration,there are two regions in the cyclone.In the particle controlling region,the particles velocity is larger than the gas velocity and all the particles are collected,which is the first separation stage.In the gas controlling region,the particles velocity is less than the gas velocity,so that the particles are collected by centrifugal force,which is the second separation stage.The total separation efficiency is the sum of the efficiencies in the two stages.The results by tandem separation model are in agreement with the experimental results for the inlet concentration in the range of 0.002—1 kg·m^-3.It is shown that the critical concentration has a significant effect on the calculation for the total efficiency.In the tandem separation model,the structure factors and particle properties are taken into account,which meets the requirement of engineering design and calculation.design and calculation.