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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280r/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.
Aiming at the phenomena of floating, sinking, sticking and hanging in rubber asphalt mixed with matrix asphalt, the geometric model of rubber asphalt mixing tank was established. Based on computational fluid dynamics software, unsteady solid-liquid two phase Flow numerical simulation and analysis of the factors that affect the uniformity of mixing, such as the blade diameter, blade position, baffle and stirring speed, etc. The results show that the size of the appropriate blade diameter and the appropriate blade position is conducive to the formation of the cycle axis And the steady flow is reduced, the tangential flow is effectively reduced by installing the baffle, and the agitator speed does not affect the basic flow pattern of the internal flow field, but the suitable stirring speed improves the mixing uniformity. The mixing uniformity and simulation results confirm that, When the diameter of the stirrer is 800 mm, the distance between the blades and the bottom of the tank is 680 mm, the blade width is 100 mm and the stirring speed is 280 r / min, the rubber powder is more evenly distributed and the mixing uniformity is 0.24, The simulation results are in good agreement with the experimental results.