采用计算流体力学组分输运模型和SST k?ω湍流模型,在Re=3000~9000范围内研究Lightnin静态混合器内萘酚(组分A)与对氨基苯磺酸(组分B)偶合氮化串联竞争反应,分析化学反应场中各组分浓度分布规律、湍流流动及微观混合特性。Lightnin内插件能够推进管内主反应的高效进行,副产物S较少且其浓度在0.0004~0.03 mol/L,而主产物R的浓度较副产物S高两个数量级。湍流强度随着雷诺数的增大呈现明显上升趋势,Re=3000时z/l=2处的湍流强度峰值(达到2.95)是出口处的2.02倍。湍流耗散率ε随径向位置的增加而减小,wA=0.5~0.6时浓度对ε的影响微弱,而wA=0.7~0.9时ε的轴向和径向分布随着浓度的增大逐渐减小,wA=0.6~0.9时z/l=10处的ε相比于wA=0.5时依次减小2.43%, 8.86%, 19.80%, 42.25%。Re=6000~9000时径流数呈周期规律分布,偶数旋流元件内形成小峰值,奇数元件内则内凹。组分A与组分B在摩尔比一定的条件下,Re=4000~9000出口位置处的微观混合特性相比于Re=3000时分别增强18.22%~55.34%。
Using the computational fluid dynamics (CFD) component transport model and SST k?ω turbulence model, A series competitive nitride reaction between naphthol (component A) and para aminobenzene sulfonic acid (component B) was used as the working system to determine the concentration distribution of materials in the range Re=3000~9000 in the Lightnin static mixer. The concentration distribution, turbulent flow, and micromixing characteristics of each component in the chemical reaction field were analyzed. The Lightnin insert can promote the efficient process of the main reaction in the tube. The by-product S was small and its concentration was between 0.0004 and 0.03 mol/L, while the concentration of the main product R was two orders of magnitude higher than that of the by-product S. The turbulence intensity increased obvously with the increasing of Re. The peak value of turbulence intensity reached 2.95, which was 2.02 times than the minimum value at the exit when z/l=2 and Re=3000. The critical value of turbulent kinetic energy appears when wA=0.7, and the turbulent kinetic energy increases with the increase of concentration when wA<0.7, and turbulent kinetic energy decreases with the increase of concentration when wA>0.7. The turbulent dissipation rate decreases gradually with increasing of radial distance and concentration. Compared with wA=0.5, the turbulent dissipation rate of z/l=10 decreases by 2.43%, 8.86%, 19.80%, and 42.25% under wA=0.6~0.9. The radial-flow number is distributed periodically which is formed a small peak value in an even number of the swirl element, while a concave trend in the odd number at Re=6000~9000. Under the condition of the same mole ratio and concentration of components A and B, the micromixing characteristics at the outlet increased by 18.22%, 30.38%, 38.91%, 45.52%, 50.97%, and 55.34% respectively at Re=4000~9000 compared with Re=3000.