碟式离心机内流场及固液两相分离过程的研究

摘要

Using disc centrifuge as the research object,the three-dimensional physical model of 20 floors of disc clearances and sediment area inside the drum was established,the fluid dynamics analysis software of fluent for numerical simulation was applied on solid-liquid two-phase separation study,the experimental separation was compared and analyzed.The results show that Solid-liquid two-phase substantially the same on circumferential velocity,the liquid in the disc area is almost no lag relative to the disc,while,in sediment bowl area exist lag relative to the drum ,the degree of hysteresis increases with drum speed;there is little difference in the radial velocity for solid-liquid two-phase;the largest centrifugal hydraulic inside drum get from simulation is small than theoretical calculation results;it appeared the phenomenon of uneven distribution of incoming material near the feed opening;the two-phase separation efficiency increased with the drum speed;the separation efficiency by experimental measured consistent with the simulation results.The results could be used as a guide for finite element analysis and of separation process optimization.%以碟式离心机为研究对象,建立了其转鼓内20层碟片间隙以及沉渣区域的三维物理模型,用流体分析软件FLUENT对转鼓内固液两相分离过程进行了数值模拟,并进行了分离效果的试验验证.结果显示,周向速度上,固液两相速度基本相同,在碟片间隙液体相对碟片滞后小,转鼓沉渣区域液体运动相对转鼓滞后较大,且滞后程度随转鼓转速的增加而增加;固液两相在径向上存在速度差;模拟得到的转鼓内最大离心液压比理论计算得到的结果小;碟片进料颗粒浓度逐层降低,碟片排液口浓度也逐层减小;在碟片进料孔附近会出现进料分布不均的现象;两相分离效率随着转鼓转速增加而提高;试验测得的分离效果与模拟结果较为吻合.研究结果对碟式离心机转鼓的有限元分析以及分离过程的优化具有指导意义.