液体连续相撞击流反应器中流体混合时间的数值模拟

在混合时间理论计算基础上利用CFD技术模拟连续操作的LISR混合过程, 数值计算与验证混合时间的变化规律。结果表明, 随着输入比有效功率增大, 混合时间先急剧减小后逐渐趋于平稳;LISR撞击区一次撞击局部混合时间在0.25 s以内, 与经验公式或理论公式计算所得结果在数量级上完全一致, 证明数值方法分析一次撞击局部混合时间是可行的, 而且可以弥补实验无法测定中间过程参量的不足;进一步数值分析宏观混合时间与微观混合时间发现, 二者大小相差1个数量级, 但二者变化规律处于一种联动平衡状态, 该结果与前期理论分析结果一致;本研究所得结论可为后续LISR混合强化机理与性能研究提供定量参考。

Numerical simulation of fluid mixing time in liquid impinging streams reactor

On the basis of theoretical calculation, the mixing process under continuous operation in liquid impinging streams reactor (LISR) was simulated by CFD and the change of mixing time was calculated and verified numerically. With increasing effective specific power, mixing time decreased rapidly at first and then tended to be smooth and steady. The local mixing time in one stroke of impinging mixing was less than 0.25 s, which fully agreed with the order of magnitude figured out by empirical model and theoretical model. It was demonstrated that using the numerical method to analyze local mixing time is feasible. It could also make up for the deficiency of experimental research. To further study macromixing time and micromixing time numerically, it was found that macromixing time was one order of magnitude greater than micromixing time, but both changes were fundamentally consistent and were in a linkage state of equilibrium which was in accordance with our previous theoretical analysis. These conclusions could be used as the mechanism methods and quantitative reference for follow-up study of mixing enhancement mechanism of LISR.