Abstract: The phenomena of floating, sinking, wall hanging and sticking in the mixing process of rubber powder and asphalt in a stirred tank were studied, the mixing tank model of rubber asphalt was established, and the mixing process inside the tank with solid-liquid two-phase numerically simulated in a unsteady state based on CFD software. The effects of the blade diameter, blade position, baffle and stirring speed on the mixing uniformity were analyzed. The results showed that the suitable size and position of blade were beneficial to the form of cyclic axial flow and reduction of steady flow. The installation of the baffle reduced the occurrence of tangential flow. The stirring speed did not affect the basic form of internal flow, but the suitable speed improved the mixing uniformity. In addition, the mixing uniformity matched up with the simulation results, and under the agitator parameters of blade diameter 800 mm, blade position 680 mm, blade width 100 mm, and rotational speed 280 r/min, the distribution of rubber particles after optimization was more uniform at the mixing uniformity of 0.24, which was in the complete off-bottom suspension, fitting well to the simulation results.

Key words: numerical simulation, rubber powder, asphalt, mixing, stirred tank, flow field

摘要： 针对橡胶粉与基质沥青混合过程中出现的漂浮、沉底、粘壁及挂料现象，建立了橡胶沥青搅拌罐的几何模型，基于计算流体力学软件对罐内混合过程进行非定常固液两相流数值模拟，分析了影响混合均匀性的因素，如桨叶直径、桨叶位置、挡板及搅拌速度等. 结果表明，尺寸适宜的桨叶直径与合适的桨叶位置有利于形成循环的轴向流，并减少定常流现象，安装挡板有效减少了切向流，搅拌器转速不影响内部流场的基本形态，但适宜的搅拌转速提高了混合均匀性. 混合均匀度与模拟结果印证，且当搅拌器直径800 mm、桨叶距离罐底680 mm、桨叶宽100 mm、搅拌速度280 r/min时，优化后橡胶粉的分布较均匀，混合均匀度为0.24，处于完全离底悬浮状态，模拟结果与实验结果较吻合.

关键词: 数值模拟, 橡胶粉, 沥青, 混合, 搅拌罐, 流场