双层intermig桨式搅拌槽流动场数值模拟

搅拌器被广泛应用于许多工业过程中。本文对双层intermig桨式搅拌槽内的混合过程进行了三维模拟,采用多重参考系法(MRF)及标准k-ε模型,分析了不同工况下,桨叶直径及离底高度对流场及搅拌功率的影响,绘制了Np-Re关系图。结果表明:离底高度的变化对搅拌槽流场性能的影响非常明显,流动模拟可获得详细的流场分布及各项特性参数,计算结果可为工业搅拌过程提供工艺参考。

种分槽改进Intermig桨搅拌性能的实验研究

为了研究改进的Intermig桨的搅拌性能,在无挡板的氧化铝种分搅拌槽内,采用PC6D颗粒浓度测量仪对水-玻璃珠液-固体系在不同条件下的颗粒轴向和径向局部浓度进行了测量与分析.结果表明,较高的搅拌转速和体系粘度更有利于固体颗粒的悬浮.粘度μ=3.50×10-3Pa·s、转速n=172r/min时,实验浓度平均值是理论浓度平均值的1.011倍,可见该条件下实验浓度值与理论浓度值更接近,混合更均匀.

Experimental and CFD studies of solid-liquid slurry tank stirred with an improved Intermig impeller

The improved Intermig impeller has been used in the seed precipitation tank in China, which could enhance the mixing and suspension of Al(OH)3 particles and the power consumption declined largely. The flow field, solids hold-up, cloud height, just off-bottom speed and power consumptions were investigated in solid-liquid mixing system with this new type of impeller by CFD and water experiment methods. Compared with the standard Intermig impeller, the improved one coupled with specially sloped baffles could promote the fluid circulation, create better solids suspension and consume less power. Besides lower impeller off-bottom clearance is good for solid suspension and distribution. The just-off-bottom speed was also determined by a power number criterion. Meanwhile, the predicted results were in good agreement with the experimental data.

种分槽高性能HSG/HQG搅拌装置的研发

用fluent软件对铝酸钠氢氧化铝料浆在搅拌槽内的流动特征、桨叶搅拌效果和功率消耗等进行了数值模拟,通过小型实验槽和中型工业搅拌槽的测试验证,得到正确的数学模型和边界条件,使模拟和实测达到吻合一致。模拟计算采用多面体网格、滑移网格法和标准k-ε瑞流方程,氢氧化铝体积分数为33%。然后用fluent软件模拟得到了优化的桨叶形状等参数,开发了高性能HSG/HQG组合搅拌桨。新型搅拌桨首先应用在山西铝厂的Φ6.5×10米氢氧化铝搅拌槽,之后,东方希望氧化铝厂Φ14×35.5米种分槽上也获得应用,搅拌效果良好无沉淀结疤,节能效果显著。将HSG/HQG組合搅拌桨与大型搅拌槽使用的INTERMIG搅拌桨和CBY长薄叶搅拌桨进行性能对比。结果表明,在同样的物性参数下,HSG/HQG组合搅拌桨比INTERMIG搅拌桨和CBY长薄叶搅拌桨能耗降低40%左右,槽底部无结疤,同时具有大排量和低剪切的特点。