搅拌釜内稠密固-液混合的数值模拟  

Numerical study on dense solid-liquid mixing in a stirred tank

作　　者：徐子龙 孙宁 杨潮 刘宝庆[1] 金志江[1] XU Zi-long;SUN Ning;YANG Chao;LIU Bao-qing;JIN Zhi-jiang(Institute of Process Equipment,Zhejiang University,Hangzhou 310027,China)

机构地区：[1]浙江大学化工机械研究所,浙江杭州310027

出　　处：《高校化学工程学报》2020年第4期890-896,共7页Journal of Chemical Engineering of Chinese Universities

基　　金：国家自然科学基金(21978255,21776246);中央高校基本科研业务费项目(2019QNA4020)。

摘　　要：基于颗粒动力学理论对稠密固-液搅拌釜进行模拟,探究固相分布、固相悬浮高度及沉积高度随转速的变化规律。结果表明,采用颗粒动力学理论(KTGF)模型能够较好地预测稠密固-液混合状态。在较低的转速下,釜底的固相浓度较高,桨叶下方、釜壁与釜底的连接处易形成固相的沉积,且搅拌釜上方会出现清液区域。随着转速的增加,固相在轴向分布逐渐均匀,固相沉积区域及固相悬浮高度分别缩小和升高。但是,当转速达到一定程度后,固相均匀度及固相悬浮高度的改善不明显。此外,将固相均匀度法、固相沉积高度法及固相悬浮高度法预测的临界离底悬浮转速与实验数据进行比较,模拟值分别低于、高于和低于实验值。The dense solid-liquid flow in a stirred tank was simulated based on the kinetic theory of granular flow(KTGF),and the effects of impeller speed on solid distribution,cloud height and sedimentation bed height were investigated.The results show that the KTGF model can well predict the dense solid-liquid mixing state in the stirred tank.At the lower impeller speed,the solids have higher concentration at tank bottom and clear liquid forms in the upper zone,and solids are easy to sediment at location below the impeller and near the junction of tank wall and bottom.With the increase of impeller speed,the solid distribution in axial direction is gradually uniform,cloud height increases and the sedimentation area reduces.However,the improvement in solid homogeneity and cloud height is not obvious when the impeller speed increase and reaches a certain value.In addition,the critical just off-bottom suspension impeller speed predicted by the solid homogeneity method,sedimentation bed height method and cloud height method is lower,higher and lower than the experimental data,respectively.

关 键 词：搅拌釜 颗粒动力学理论 稠密固-液两相流 计算流体力学 

分 类 号：TQ051.7[化学工程]