A Contraction-expansion Helical Mixer in the Laminar Regime

doi:10.1016/S1004-9541(14)60035-5

Abstract

Abstract: A contraction-expansion helical mixer which combines several features, viz. helical pipes for induction of secondary flows and sudden expansion and contraction array for expansion vortices, has been designed to enhance flow mixing. A fast competitive-consecutive diazo coupling reaction is used to test the mixing efficiency of contraction-expansion helical mixer. Furthermore, an image processing technique is applied for data visualization and monitoring the extent of mixing. The mixing performance is found to be superior in comparison to the regular helical mixer in the range of Reynolds number from 170 to 1540. Moreover, the mixing time of contraction-expansion helical mixer was found to be reduced by more than 25% compared to the regular helical pipe. Finally, a simple correlation is proposed for predicting the mixing time.

Key words: contraction-expansion, helical pipe, mixing, laminar flow

摘要： A contraction-expansion helical mixer which combines several features, viz. helical pipes for induction of secondary flows and sudden expansion and contraction array for expansion vortices, has been designed to enhance flow mixing. A fast competitive-consecutive diazo coupling reaction is used to test the mixing efficiency of contraction-expansion helical mixer. Furthermore, an image processing technique is applied for data visualization and monitoring the extent of mixing. The mixing performance is found to be superior in comparison to the regular helical mixer in the range of Reynolds number from 170 to 1540. Moreover, the mixing time of contraction-expansion helical mixer was found to be reduced by more than 25% compared to the regular helical pipe. Finally, a simple correlation is proposed for predicting the mixing time.

关键词: contraction-expansion, helical pipe, mixing, laminar flow

LIANG Dong, ZHANG Shufen. A Contraction-expansion Helical Mixer in the Laminar Regime[J]. Chin.J.Chem.Eng., 2014, 22(3): 261-266.

梁栋, 张淑芬. A Contraction-expansion Helical Mixer in the Laminar Regime[J]. Chinese Journal of Chemical Engineering, 2014, 22(3): 261-266.

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