The role of circular folds in mixing intensification in the small intestine: A numerical study

Jinping Zha (1) , Siyu Zou (1) , Jianyu Hao (2) , Xinjuan Liu (2) , Guillaume Delaplace (3) , Romain Jeantet (4) , Didier Dupont (4) , Peng Wu (1) , Xiao Dong Chen (1) , Jie Xiao (1)

1 Soochow University
2 CUMS - Capital University of Medical Sciences [Beijing]
3 UMET - Unité Matériaux et Transformations - UMR 8207
4 STLO - Science et Technologie du Lait et de l'Oeuf

The inner wall of the intestine has multiscale structures whose roles, beyond the increase of surface area for absorption, are yet to be discovered. In this study, the mixing process in a human duodenum with circular folds, driven by segmentation contraction, was simulated using a multiphysics model, making it possible to track the evolution of mixing level distributions and enabling quantitative evaluation of the structural role of folds in mixing intensification. It was found that, in a laminar flow regime, circular folds intensify both radial and axial mixing by synergistically offering prominent and long-lasting swirls/vortices, high fluid velocity and high shear rates. Tall and slim folds with enlarged segmentation amplitude, frequency and wavelength can enhance mixing. The maximum enhancement ratio can reach 6.18 under the investigated conditions. These findings will also be valuable for the improved design of biomimetic soft-elastic reactors for the chemical and pharmaceutical industries.

Mots clés: nutrition; digestion; plis circulaire; intestin grêle; bol alimentaire; étude numérique

Domaines: Alimentation et Nutrition

Jinping Zha, Siyu Zou, Jianyu Hao, Xinjuan Liu, Guillaume Delaplace, et al.. The role of circular folds in mixing intensification in the small intestine: A numerical study. Chemical Engineering Science, 2021, 229, pp.116079. ⟨10.1016/j.ces.2020.116079⟩. ⟨hal-02975862⟩