Solid-liquid mixing performance in a stirred tank with a double punched rigid-flexible impeller coupled with a chaotic motor

Abstract

The mixing performance of solid-liquid system was investigated in a stirred tank with a double rigid impeller, a double rigid-flexible impeller, a double punched rigid-flexible impeller, and a double punched rigid-flexible impeller coupled with a chaotic motor. The effects of the impeller types, the flexible connection piece width/length, the aperture size/ratio, and the variable/constant speed periods were investigated. The mixing performance was characterized by the largest Lyapunov exponent (LLE) and axial local solid concentration profile. The results indicated that the double punched rigid-flexible impeller and chaotic motor could enhance the LLE value of solid-liquid mixing system on the basis of the double rigid-flexible impeller and traditional motor under the same power consumption. The variation in solid homogeneous degree was in good agreement with that of LLE. It was found that the double punched rigid-flexible impeller coupled with a chaotic motor could further improve the solid suspension quality and energy efficiency compared with the double rigid impeller or double rigid-flexible impeller coupled with a traditional motor in the solid-liquid mixing process.