화학공학소재연구정보센터
Chemical Engineering and Processing, Vol.122, 1-9, 2017
Intensification of chaotic mixing in a stirred tank with a punched rigid-flexible impeller and a chaotic motor
Laminar mixing of non-Newtonian CMC solution was investigated experimentally in a stirred tank with a rigid impeller, a rigid impeller coupled with a chaotic motor, a rigid-flexible impeller, a rigid-flexible impeller coupled with a chaotic motor, a punched rigid-flexible impeller, and a punched rigid-flexible impeller coupled with a chaotic motor. Visualization experiment was used to reveal the presence of segregated regions, and observe the structure changes of segregated regions. The mixing performance was characterized by the largest Lyapunov exponent (LLE) and dimensionless mixing time (NTm). Results showed that punched rigid-flexible impeller could further enhance the value of LLE, namely, the chaotic extent of mixing system compared with rigid impeller and rigid-flexible impeller, and the NTm for punched rigid-flexible impeller was shorter than that for rigid impeller and rigid-flexible impeller at the same consumption per unit volume (P-v). The chaotic motor could further increase LLE value, and reduce the NTm on the basis of the normal motor. Moreover, the optimum aperture diameter and aperture ratio of punched rigid-flexible impeller were 8 mm and 12%, respectively, and the variable speed period of 10 s and constant speed period of 5 s of chaotic motor were particularly suitable for the laminar mixing process.