三股对撞式撞击流反应器微观混合性能研究

Micromixing efficiency of three-impinging-jet reactor

采用高速数码相机对三股对撞式撞击流反应器不同入口雷诺数下的流场特征进行了研究,并采用碘化物-碘酸盐平行竞争反应体系,考察了不同喷嘴直径下的入口雷诺数、不同溶液体积流量比对离集指数的影响。结果表明:入口雷诺数、溶液体积流量比对离集指数有明显的影响。增大入口雷诺数,三股流体高速撞击破碎成的液滴粒径逐渐减小,液滴雾化程度增加,离集指数减小,微观混合效果增加;增大体积流量比,溶液局部浓度增大,导致混合不均匀,离集指数增大。与传统撞击流反应器相比,三股对撞式撞击流反应器离集指数为传统撞击流反应器的2/5,表现出了较好的微观混合性能,更适用于不等溶液体积流量比的液液快速混合反应。

High-speed digital camera was used to visualize and investigate the evolution of the flow characteristics at different injection Reynolds numbers in three-impinging-jet reactor. The iodide-iodate parallel-competitive reactions were applied to study the effects of injection Reynolds numbers at different nozzle diameter and volume flow rate ratio on segregation index. The experimental results show that injection Reynolds number and volume flow rate ratio have noticeable effects on segregation index. With increasing of injection Reynolds number,the smaller droplets and the intensive atomization of the liquid sheet were observed in captured high-speed digital camera images when three streams rapidly collided, leading to decreasing of segregation index, improving micromixing quality.Increasing volume flow rate ratio increased the local concentration of one stream,producing inhomogeneous flow field whose micromixing efficiency was poor and segregation index was high. Compared with conventional impinging jets reactor,the value of segregation of three-impinging-jet reactor is 2 /5 than that of conventional impinging jets reactor,which behaviors better micromixing efficiency. It is more suitable for fast mixing reactions at unequal volume flow rate ratio.