Numerical investigation of a two-phase system on swallowing behavior in dysphagia: A case study on cress seed gum–xanthan gum thickened liquids

Abstract

In this paper, a new approach for predicting the swallowing behavior of dysphagia was developed by a simulation of the pharyngeal area through a novel two-phase finite volume model. The physical properties of a bolus (surface tension, density, and viscosity), and the tongue driving pressure, which can affect the bolus transmission in the pharynx, were implemented in the proposed model to ameliorate the swallowing scenario simulation. Furthermore, the paper deals with the effect of cress seed gum (CSG) and xanthan gum (XG), as thickeners, at different concentration levels on the developed model for the swallowing behavior. The tongue pressure was assumed as a linear distribution with bolus axial-radial motion couplings. All samples containing the thickeners exhibited a typical shear-thinning behavior. The non-Newtonian fluids were demonstrated that these fluids are relatively safer and more effective than Newtonian fluids to swallow for patients with dysphagia by decreasing swallowing flow rate. Moreover, the results of pressure-inlet and flow rate diagrams confirmed that non-Newtonian fluids might lead to swallowing amelioration as well as aspiration risk reduction with increasing the thickeners’ concentration. The presented computational fluid dynamic (CFD) method showed that the proposed model could provide a practical procedure for classifying dysphagia products to ameliorate the swallowing scenario simulation.