Numerical analysis of extensional flow through the pharyngeal duct

2nd International Conference on Rheology and Modeling of Materials

Preciado-Méndez, M.^1 ; Salinas-Vázquez, M.^2 ; Vicente, W.^2 ; Brito-De La Fuente, E.^3 ; Ascanio, G.^4

Programa de Maestría y Doctorado en Ingeniería, Universidad Nacional Autónoma de México, Ciudad Universitaria, Mexico^1

Instituto de Ingeniería, Universidad Nacional Autónoma de México, Circuito Escolar, Mexico^2

Fresenius-Kabi Deutschland GmbH, Bad Homburg, Germany^3

Centro de Ciencias Aplicadas y Desarrollo Tecnológico, Universidad Nacional Autónoma de México, Circuito Exterior Ciudad Universitaria, Mexico^4

关键词: Non-Newtonian fluids;    Nutritional supplements;    Recirculation zones;    Rheological characterization;    Rheological indices;    Strong dependences;    Swallowing disorders;    Three-dimensional model;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/790/1/012025/pdf
DOI  :  10.1088/1742-6596/790/1/012025

来源: IOP

【 摘 要 】

The flow through the pharynx from the glossopalatal junction (GPJ) to the upper esophageal sphincter (UES) has been numerically investigated with a non-Newtonian fluid obeying the power-law with similar rheological indices to a contrast medium used in videofluroscopy. For that purpose, a three-dimensional model of the transport of food bolus along the pharynx has been proposed using the immersed boundaries method, which allow representing the shape of the pharynx using Cartesian grids. The pharyngeal wall has been considered to be an elastic membrane. Flow fields in terms of the axial velocity, pressure, shear rate and strain rate were obtained. Results show that the highest velocity concentrates in the central stream as the fluid enters into the pharynx. In addition, as the flow quits the pharynx, a recirculation zone appears inside the cavity, resulting in low velocity zone, which increases with the coefficient of elasticity. A strong dependence on the coefficient of elasticity was observed on the pressure fields; so that as such a coefficient increases, the pressure in the pharyngeal wall will increase. It has been also observed that the bolus head travels faster than the bolus tail, which indicates that the bolus is not only subjected to shear but also to elongation. Results from this work can be further used for a rheological characterization (shear and extension) of oral nutritional supplements for patients suffering from swallowing disorders.