喷射反应器内液-液湍流微观混合的研究

Research on turbulent micro-mixing in a jet reactor

通过定义局部分离度,来定量表征喷射器内液-液湍流微观混合规律。其定义式为:(实验所得H^+浓度-模拟所得H^+浓度)/模拟所得H^+浓度。选用酸碱反应体系,利用PLIF技术得到沿喷射器轴线的H^+浓度;采用Fluent软件,利用Standard k-ε模型,模拟获得相同操作条件下的H^+浓度变化趋势。得到不同操作条件下,分离度沿喷射器轴线的变化,结果表明:(1)引流速度不变,喷嘴速度越大,两流体越容易达到微观尺度的均匀混合;(2)喷嘴速度不变,引流速度越大,两流体反而不容易达到微观尺度上的均匀混合;(3)速度比一定的情况下,喷嘴速度越大,越有利于流体的微观混合。

Local separating degree was defined to quantificationally characterise liquid-liquid turbulent micro-mixing in a jet reactor, which was defined as：（the experimental H^＋ concentration-the simulative H^＋ concentration）/the simulative H^＋ concentration. Acid-base reaction was selected to study micro-mixing character. H^＋ concentration along the axis of jet reactor was got by the means of PLIF; Using Fluent, H^＋ concentration under the same operational conditions was obtained through standard k-ε. The change of separating degree along the axis of jet reactor under different operational conditions was received. The result shows： （1） With constant suction flow speed, the bigger the ejection flow speed is, the easier it is to be uniform at micro-scale. （2） With constant ejection flow speed, the bigger the suction flow speed is, the more hard it is to be uniform at micro-scale. （3） With constant speed ratio, the bigger the ejection flow speed, the easier it is to be uniform at micro-scale.