基于CFD的陶瓷干法制粉造粒室挡板数目优化

Optimization of Baffle Number of Granulation Chamber for Ceramic Dry Powder Based on CFD

为研究造粒室底部挡板数目对干法制粉混料过程的影响,构建了欧拉-欧拉气固两相流数学控制方程,建立不同挡板数目物理模型,采用修正后的RNGk-ε模型模拟造粒室内湍流情况,对不同挡板数目的干法制粉造粒室内的流场进行数值模拟,分析了不同挡板数目的造粒室内颗粒体积分布、速度场、湍动能、湍动能耗散的差异,并将数值模拟与实验进行对比。结果表明:挡板数目对混料过程有一定影响,分布适当挡板数目能够提高颗粒体积分布、改善合成速度,具有良好的湍动能及湍动能耗散,有利于促进颗粒混合;带挡板的造粒室流场分布优于无挡板造粒室,挡板数目增加时,造粒效果随着挡板数目的增加先增强后减弱;当挡板数目为4片时,颗粒体积分布达到了72%,堆积现象有较大改善,速度较好,耗散情况得到改善,有利于造粒室内流体介质的有效混合;当挡板数目分别为0、2、4、6片时,颗粒的合格率分别为82%、84%、90%、85%,处于30~60 mesh之间的优良颗粒分别占58%、62%、71%、64%;实验结果验证了数值模拟的正确性,为旋转流场式造粒设备的结构优化和设计提供了一定的理论指导。

In order to study the influence of the number of baffles at the bottom of the granulation chamber on the mixing process of dry powder,the Euler Euler gas solid two phase flow mathematical control equation was constructed,and the physical model of different baffle number was established. The modified RNG k-ε model was used to simulate the turbulent flow in granulation chamber. Numerical simulation of flow field in granulation chamber for ceramic dry powder with different number of baffles was carried out. Analyzing the different baffle number of granulation chamber particle volume distribution,velocity field,turbulent kinetic energy,turbulent kinetic energy dissipation,and the simulated results were compared with the experimental results. The results show that： the number of baffle plates have a certain impact on the mixing process,the appropriate number of baffle plates can improve the distribution of volume distribution,improve the speed of synthesis of particles,have better turbulent kinetic energy and turbulent kinetic energy dissipation,is conducive to the promotion of particle mixing; the distribution of flow field in the prilling chamber with baffles is better than that without baffle,when the number of baffles increases,the granulation effect increases first and then decreases with the increase of bafflenumber; when the number of baffles is 4,the particle size distribution is 72%,the accumulation phenomenon is greatly improved,the speed is better,the turbulence energy dissipation is improved,and it is beneficial to the effective mixing of the fluid medium in the granulation chamber; when the number of baffles is 0,2,4 and 6,the qualified rate of particles is 82%,84%,90% and 85%,respectively,the fine particles between 30-60 mesh accounted for 58%, 62%, 71% and 64% respectively; the experimental results verify the accuracy of the numerical simulation, and provide some theoretical guidance for the structural optimization and design of the rotary flow granulator.