CIESC Journal ›› 2020, Vol. 71 ›› Issue (10): 4611-4620.doi: 10.11949/0438-1157.20200675

• Fluid dynamics and transport phenomena • Previous Articles     Next Articles

Chaotic mixing and droplet dispersion characteristics of liquid - liquid with elastic combined impeller

Zuohua LIU1(),Chuang WANG1,Wei SUN1,Changyuan TAO1,Yundong WANG2   

  1. 1.School of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400044, China
    2.Department of Chemical Engineering, Tsinghua University, Beijing 100084, China
  • Received:2020-06-02 Revised:2020-07-29 Online:2020-10-05 Published:2020-08-15
  • Contact: Zuohua LIU


Traditional mixing and clarification tanks generally use rigid stirring blades to achieve liquid-liquid two-phase mixed extraction, which generally suffers from low efficiency and high energy consumption. A kind of elastic combined impeller was used in the mixing clarifier in this work to enhance the liquid-liquid biphase mixing behavior. Lyapunov exponent (LLE) and multiscale entropy (MSE) were used to characterize the chaotic state of the system, the particle size distribution and D32 were used to characterize the dispersion effect. The influence of impeller type (elastic combined impeller, rigid-flexible combined impeller and rigid impeller), spring length, wire diameter and outer diameter on mixing effect was studied. The results indicated that compared with the rigid impeller and the rigid-flexible combined impeller, the elastic combined impeller strengthens the energy dissipation mode of the flow field through the deformation and energy storage of the spring, improves the dispersion effect of the dispersed phase, and was conducive to the chaotic mixing of the liquid-liquid biphase. When stirring speed N = 200 r/min, the spring wire diameter was 0.6 mm, the relative length of the spring was 1.2, and the external diameter of the spring was 7 mm, the LLE value and the amplitude of MSE were the largest and the MSE values fluctuate most strongly. At the same time, there was a log-linear relationship between the D32 of dispersed phase and the stirring speed in each stirring system, and the droplet size of dispersed phase in the elastic combined impeller system was smaller and more.

Key words: elastic combined impeller, mixing, mixer-settler, Lyapunov exponent, multiscale entropy, particle size distribution, D32

CLC Number: 

  • TQ 027.2


Schematic diagram of elastic combined impeller enhancing mixing"


Physical property of mediums"



SOPAT measurement system"


Structure of mixer-settler"


Impellers used in experiment"


Effect of impeller type on LLE"


Effect of outer diameter of spring on LLE"


Effect of length of spring on LLE"


Effect of wire diameter of spring on LLE"


Effect of impeller type on MSE"


Effect of outer diameter of spring on MSE"


Effect of length of spring on MSE"


Effect of wire diameter of spring on MSE"


The distribution of dispersed phase droplets in different impeller systems at different stirring speeds"


Effect of stirring speed on droplet distribution"


The effect of stirring speed on D32"

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