Gas-rigid-flexible compound blade coupling enhanced experimental study on chaotic mixing of multiphase flow

Efficient fluid mixing is essential for process intensification. This study proposes a new method in which gas-rigid-flexible composite blades are coupled to enhance chaotic mixing in multiphase flow systems. The rigidity and flexibility of the blades were adjusted by intermittent gas injection, which increased the effectiveness of mixing of the liquid-liquid two-phase fluid. This study investigates the influence of different process parameters on the mixing efficiency and quantifies the chaotic characteristics of fluid mixing through pressure-time series analysis of multiscale entropy and the 0–1 test. A high-speed camera recorded the bubble movement in the flow field, while particle image velocimetry (PIV) revealed the enhancement of the properties of the flow field in the system due to the suspended motion of the particles. Using suitable process parameters, gas-rigid-flexible composite blade coupling significantly enhanced the mixing effect, where the mixing time of the G-RFCP system was reduced by 1.42 times compared to that of the CP system. Bubble motion, deformation, and rupture enhanced the mechanical agitation, increasing the intensity of the turbulence and chaotic behaviour. Flow-field analysis indicated a three-fold increase in the vorticity and a 1.04-fold increase in the velocity difference for the G-RFCP system compared with those of the CP system. This study provides theoretical and experimental foundations for understanding chaotic mixing in liquid-liquid two-phase fluids.