多层搅拌桨流动场的测量与数值模拟

应用商业计算流体力学软件CFX对搅拌槽内多层搅拌桨的流场进行了模拟，并与LDV测试结果进行了比较.低Reynolds数k-ε模型和代数应力模型流型吻合较好；标准k-ε双方程模型和RNG k-ε模型下层桨流场出现不同程度的扭曲，与实验测试结果不符.速度分量的对比结果表明，低Reynolds数k-ε模型和代数应力模型能较准确地模拟搅拌槽内的流动场，其中尤以代数应力模型最为准确.

MEASUREMENT AND NUMERICAL SIMULATION OF FLOW FIELD IN STIRRED TANK WITH MULTIPLE IMPELLERS

In this paper the commercial software package CFX-4 is used with k-ε model, RNG k-ε model, Low Reynolds Number k-ε model and algebraical stress model to simulate the flow generated by multiple impellers in a cylindrical baffled tank. The equations are discretised by the finite-volume approach. The mesh is divided into two parts which are fixed to their respective frames of reference, one being stationary and the other rotating with the impeller. At the interface between these two parts the rotating mesh slides over the fixed one at each time interval. The computation proceeds simultaneously over the whole flow field and the solutions in both rotating and stationery domains are coupled at all times.The simulation results show that the algebraical stress model predictions successfully reproduce the characteristics of flow, and are in good agreement with those obtained by LDV measurement. However the flow field simulated by k-ε model and RNG k-ε model is contorted by the underlayer impeller, and showes significant variation with experimental results.