搅拌容器内氧气非均相传质过程的数值模拟

着重考察了搅拌器类型以及搅拌转速对氧气动态传质过程的影响，通过采用计算流体力学 (computational fluid dynamics，CFD) 对氧气动态传质过程进行了数值模拟,同时结合实验，对模拟结果进行了验证.结果表明，（1）采用Fluent软件并结合用户自定义方程（user defined function，UDF）能够很好地模拟出实际搅拌器内流场分布，模拟结果与采用粒子成像技术（particle image velocity，PIV）的实验测量结果相符;（2）采用氧气传质模型能预测氧气在搅拌器内的动态传质过程，同时氧气浓度与溶解时间的对数关系式能较好描述试验搅拌器内氧气动态传质过程;（3）在相同搅拌速度下,圆盘涡轮式搅拌器产生的湍流动能分布范围要大于桨式搅拌器产生的湍流动能,而且湍流动能分布更均匀，湍流强度更大.因此采用圆盘涡轮式搅拌器有利于增强氧气传质过程的进行;（4）在搅拌器类型相同时，随着转速的增加，容器内溶解氧浓度随之增加；圆盘涡轮式搅拌器比桨式搅拌容器内溶解氧的浓度要高，圆盘涡轮式搅拌器更有助于氧气的传质.

Numerical simulation on process of heterogeneous mass transfer of oxygen in stirred tank

The influences of impeller type and stirring rate of agitator on the process of oxygen mass transfer in a vessel were investigated by experimental studies and computational fluid dynamics(CFD) simulations.To verify the accuracy of CFD simulations,experiments were carried out.The results of simulations with user defined function(UDF) of the effects of impeller type and stirring rate on the velocity field were in good agreement with the output of particle image velocity(PIV).The oxygen mass transfer model can be used to predict the process of oxygen mass transfer in a vessel,and the logarithmical expression can successfully describe the relation between the oxygen concentration and the dissolution time. The disc impeller can bring larger turbulent kinetic energy dissipation than the narrow impeller,thus accelerating the oxygen mass transfer in the vessel. In the case of same impeller type and vessel geometry,the dissolution oxygen concentration grows faster with increasing impeller speed.