【摘要】 采用FLUENT软件的多重参考系(MRF)及标准k-ε模型,将速度场与浓度场方程分开进行求解,对单层轴流式三叶CBY翼形桨搅拌槽内的混合过程进行了数值模拟,所得的混合时间的模拟结果与实验值相吻合。同时采用数值模拟的方法研究了不同的示踪剂加料点、监测点位置及操作条件对混合时间的影响规律;模拟结果表明,混合过程主要由搅拌槽内的流体流动所控制,混合时间与示踪剂加料点及监测点位置密切相关。上述的研究结果对于工业搅拌反应器的优化具有一定的参考意义。更多还原

【Abstract】 Stirred reactors are widely used in many industrial processes and the mixing time is one of the key parameters for the reactor design. The mixing process in a stirred tank of 0.476m diameter with single narrow blade hydrofoil CBY impeller was numerically simulated by using computational fluid dynamics (CFD) package FLUENT 6.0. The multi-reference frame (MRF) and standard k -εturbulent model were used in the simulation. The mixing time predicted by CFD is in good agreement with the experiment. The effects of tracer feeding and detecting positions on mixing time were investigated. The mixing process is dominated by the flow field in the stirred tank. For certain detecting positions, comparing with the tracer feeding at the liquid surface, the mixing time detected is much shorter when the tracer is feeded at the impeller region. For certain feeding positions , the shortest mixing time is detected by the detectors located at the bottom region, the next shortest and the considerably longer mixing time are detected by the detectors located at the impeller region and the liquid surface, respectively. The results are of importance to the optimization of industrial stirred reactors.更多还原