黏度变化范围大的组合桨的数值模拟与应用

利用计算流体力学的方法研究了ZBK+BKS组合桨和螺带桨(LD)的流场和混合性质。对比研究了组合桨的流型、功率消耗、混合时间及混合能。结果表明:ZBK+BKS组合桨在过渡流区域,BKS起主要的流体混合作用,形成很好的整体轴向混合,而在层流区ZBK与BKS同等重要并且ZBK加强了轴向混合。ZBK+BKS组合桨的混合时间在过渡流区域要小于螺带桨,而层流区相差很小,并且二者的混合能相差较小。所以ZBK+BKS组合桨能够适用于黏度变化较大的混合过程。

Numerical simulation and application of multiple impellers with wide viscosity range

The hydrodynamics characteristics of ZBK+BKS mixer and double helical ribbon impeller were studied by using Computational Fluid Dynamics(CFD) method.The flow patterns,power consumption,mixing time and mixing energy for the two mixers were investigated.The results show that in ZBK+BKS,the main function of the ZBK impeller is in the laminar flow regime to enhance axial pumping,while the BKS impeller contributes to flow for wide Re ranges especially in the transitional flow regime.The mixing time of ZBK+BKS mixer is lower than that of double helical ribbon in the transitional flow regime,but is similar to it in the laminar flow regime.The mixing energy is approximate between the ZBK+BKS mixer and double helical ribbon.Therefore,the mixing characteristics of the ZBK+BKS mixer are excellent in a wide range of Reynolds numbers.