基于OpenFOAM大规模并行计算的烟草气流干燥装置中气固流动数值模拟

Numerical simulation of gas/solid flow in pneumatic tobacco dryer based on OpenFOAM combined with large scale parallel computing

为了探索工业级烟草CTD流态化干燥设备的气固流动特性,将开源计算流体力学软件OpenFOAM与固相颗粒的高性能大规模超级计算相结合,对CTD流态化干燥设备进行了全三维的气相流场,以及颗粒停留时间分布的数值模拟研究。同时,对比分析了添加弧形导流板结构前后CTD的气固相流场变化。结果表明,固体颗粒在工业CTD垂直干燥管中径向分布存在偏料现象,颗粒在径向方向上存在明显的浓相区域和稀相区域。添加弧形导流板结构可以改善干燥器内的固体颗粒偏料问题,使得烟丝颗粒在塔内的分布更为均匀。此外,添加导流板结构使得CTD干燥器中颗粒平均停留时间较原始结构减少1.45s,颗粒停留时间分布的方差也明显降低,这表明烟丝颗粒在添加导流板结构的CTD干燥器中的停留时间分布更为均一。

In order to investigate the gas/solid flow characteristics in CTD （Comas Tower Dryer）, OpenFOAM, an open source hydrodynamics calculation software, was combined with high performance large scale parallel computing for solid particles to simulate the full three-dimensional gaseous flow field and particle residence time distribution in CTD numerically. Meanwhile, the variations of gas/solid flow fields before and after the installation of an arc deflection plate in CTD were comparatively analyzed. The results showed that solid particles unevenly distributed in the vertical duct in radial direction, there existed obvious dense phase area and dilute phase area. The arc deflection plate could improve the distribution of solid particles and allow tobacco distributed in the tower more evenly. The mean residence time of solid particles in CTD was reduced by 1.45 s after the installation of the arc deflection plate, and the variance of residence time distribution decreased significantly as well; which indicated that the residence time of tobacco particles was more uniform in the CTD with an arc deflection plate.