挡板结构对陶瓷干法造粒室内粉体混合效果的影响
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摘要
为研究干法造粒室中挡板结构对粉体混合效果的影响,通过构造欧拉两相流模型模拟粉体与空气的相互作用,采用k-epsilon RNG离散模型模拟湍流情况,采用滑移网格法和多重参考坐标系法分别求解动区域和静区域流场,分析了在造粒室内分别加装三种结构的挡板后对颗粒体积分数和速度场的影响。结果表明:当挡板横截面分别为长方形、三角形和半圆形时,颗粒体积分数径向云图显示体积分数小于0. 31的面积占比分别约为26%、18%、2%;体积分数大于0. 37的面积占比分别约为1%、15%、27%;颗粒速度大于0. 54 m/s的面积占比分别约为45%、20%、40%;颗粒轴向速度大于0. 4 m/s的面积占比分别约为80%、40%、35%。该结果显示长方形挡板造粒室更有利于促进粉体混合,提高粉体流动性。
In order to study the influence of baffle shape on the mixing effect of powder in dry granulation chamber,the Euler two-phase flow model was used to simulate the interaction between powder and air,the k-epsilon RNG discrete model was used to simulate turbulence,the moving mesh and multiple reference coordinate were used to solve the flow field in the moving area and the static area respectively,the influence of add three kinds of baffles on particle volume fraction and velocity field were analyzed,the experimental and numerical results were compared and analyzed. The results show that when the baffle cross-section are rectangular,triangle and semicircle,the volume fraction of particles less than 0. 31 in radial-cloud map are 26%,18%,2% respectively; the volume fraction of particles more than 0. 37 are1%,15%,27% respectively; the particles speed more than 0. 54 m/s are 45%,20%,40%respectively. Particle axial velocity more than 0. 4 m/s area accounted for about 80%,40%,35%. This results express rectangular baffle granulating chamber promoted the mixing of powders and improved the fluidity.
In order to study the influence of baffle shape on the mixing effect of powder in dry granulation chamber,the Euler two-phase flow model was used to simulate the interaction between powder and air,the k-epsilon RNG discrete model was used to simulate turbulence,the moving mesh and multiple reference coordinate were used to solve the flow field in the moving area and the static area respectively,the influence of add three kinds of baffles on particle volume fraction and velocity field were analyzed,the experimental and numerical results were compared and analyzed. The results show that when the baffle cross-section are rectangular,triangle and semicircle,the volume fraction of particles less than 0. 31 in radial-cloud map are 26%,18%,2% respectively; the volume fraction of particles more than 0. 37 are1%,15%,27% respectively; the particles speed more than 0. 54 m/s are 45%,20%,40%respectively. Particle axial velocity more than 0. 4 m/s area accounted for about 80%,40%,35%. This results express rectangular baffle granulating chamber promoted the mixing of powders and improved the fluidity.
引文
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[2] Tian S S,Sun S H,Zhang Y,et al. Study on dry granulation technology for Ejiao granules[J]. Chinese Traditional&Herbal Drugs,2014.
[3]廖达海,朱祚祥,吴南星,等.陶瓷干法造粒过程坯料颗粒成形与雾化液含量的影响[J].人工晶体学报,2017,46(8):1442-1449.
[4] Huang S,Zheng M,Wang H. Numerical analysis of two-phase flow and mixing process in stirredtank[J]. China Synthetic Rubber Industry,2008,6(1):77-90.
[5]余冬玲,花拥斌,吴南星,等.陶瓷墙地砖干法造粒过程坯料粉体成形与造粒室转速的影响[J].硅酸盐通报,2017,36(10):3353-3360.
[6]王星星,刘志炎,龙伟民,等.椭圆底封头十字形挡板搅拌釜内流场研究[J].机械工程学报,2014,50(6):156-164.
[7]郭聪聪,赵恒文,许卓,等.搅拌槽内挡板对搅拌效果的数值模拟[J].给水排水,2011,47(S1):199-202.
[8]吴南星,成飞,余冬玲,等.陶瓷墙地砖干法制粉造粒过程湿含量数值分析[J].人工晶体学报,2016,45(10):2536-2541.
[9]钟天铖,汤文成,刘碧茜.推进式搅拌器固液混合的计算流体力学模拟[J].东南大学学报(自然科学版),2016,46(4):713-719.
[10]刘玉玲,郑艳,魏文礼.搅拌槽流场特性的大涡模拟研究[J].计算力学学报,2014,31(5):634-639+651.
[11]许卓,赵恒文,郑建坤.立式搅拌槽中挡板结构对搅拌能耗影响的数值模拟[J].水电能源科学,2013,31(5):162-165+197.
[12]杨锋苓,周慎杰,王贵超,等.非标准挡板搅拌槽内湍流流场的数值模拟[J].高校化学工程学报,2012,26(6):952-958.
[13]施阳和,赵进.两种不同挡板的双层桨搅拌槽三维流场数值模拟[J].化工机械,2014,41(2):211-214+231.
[14]沈春银,陈剑佩,张家庭,等.机械搅拌反应器中挡板的结构设计[J].高校化学工程学报,2005(2):162-168.
[15]孟振亮,刘梦溪,李飞,等.新型气固环流反应器内颗粒流动的CFD模拟[J].化工学报,2016,67(8):3234-3243.