不同元件长径比对液液静态混合的影响

应用FLUENT软件对5种不同长径比的静态混合器进行液液两相混合的数值模拟,得出各混合密度云图、混合不均匀系数Ψ和压力降进行比较分析。进而得出以下结论,当混合元件长径比Ar从1.0逐渐增大到2.0时,从混合密度云图和混合不均匀系数Ψ值来看,在达到预期混合效果即Ψ值达到0.05时,所需的混合元件个数随着长径比Ar的增大而减小。所需混合长度L相差不大,约为混合管直径D的1~1.5倍,混合压降相差大约7倍。所以在混合管直径D不大的情况下,选取Ar=2.0的混合器则更理想,而且单纯依靠入口流速的变化并不能对混合效果产生太大影响。

Influence of Different Ratio of Length to Diameter on Liquid-liquid Mixing in a Static Mixer

FLUENT software was used to simulate the mixing processes of liquid-liquid in 5 static mixers with different ratios of length to diameter. The mixed density image, nonuniform coefficient and pressure drop were calculated, compared and analyzed. The results showed that, when the ratio of length to diameter (Ar) increased from 1.0 to 2.0,expected mixing effect was achieved (Ψreached 0.05), the number of required mixing elements decreased with the increase of the Ar. The required mixing lengthL had little difference with others, the mixing length was 1～1.5 times of tube diameter, while pressure drop differed 7 times. The mixer withAr=2.0 was more ideal when the mixing tube diameter was small. And the change of inlet velocity alone cannot exert a great influence on the mixing effect.