Date Approved


Graduate Degree Type


Degree Name

Engineering (M.S.E.)

Degree Program

School of Engineering

First Advisor

Wael Mokhtar

Second Advisor

John Farris

Third Advisor

Kris Bergman

Fourth Advisor

Scott Hower

Fifth Advisor

Parker Huston


Dysphagia, meaning difficulty in swallowing, is a symptom of disease that occurs in young children and elderly people. It occurs particularly due to two reasons, weak neural network and/or deformities in oral section/s. The Helen DeVos Children’s Hospital’s Intensive Feeding Program takes care of children suffering from Dysphagia. In order to make the swallowing process easier and in some cases safer, thickener is added to the liquids. Depending on the requirement of thickness, the amount of thickener is varied. Although the directions to prepare the mixtures are given by the thickener product company, the required thickness is not achieved when the thickeners are added to different fluids, reason being each base fluid having its own viscosity. The hospital follows the viscosity scale given by National Dysphagia Diet (NDD) and volumetric measures for preparing Nectar thick and Honey thick liquids with various base liquids are to be determined through experimentation. The effect of time on the viscosity of the samples was studied after 24 hours of refrigeration. A Computational Fluid Dynamics (CFD) study was carried out in order to study the flow of the fluid in the oropharyngeal track to identify the necessity of specific viscosity in typical geometry, geometry affected due to cleft palate and geometry with poor Velo-Pharyngeal Range of Motion (VPROM). Using a viscometer, the viscosity values of Nectar and Honey thick samples were recorded and the necessary volumetric measures for Nectar and Honey thick scales were determined, followed by the viscosity analysis of the selected samples before and after 24 hours of refrigeration. The CFD study for the base case and two selected cases were carried out to study the flow patterns and the requirements of specific scale of viscosity for the specific oropharyngeal geometries were analysed. 4 After the experimental and numerical study on Dysphagia diet fluids regarding their viscosity, followed by the analysis of the results so obtained, the volumetric measures were provided to the clinic and time effect analysis was presented. The analysis of the flow patterns in the oropharyngeal track with different viscosities was carried out and the results were presented. It was found that the thickener contents react with the base fluids differently. Therefore, the amount of thickener to be added to each of these base fluids varies, to get the desired consistency. The numerical study reveals that altering the viscosity of the samples helps for easy swallowing. People suffering from Dysphagia with deformities in their oropharyngeal track can swallow easily by altering the viscosity of the sample. With the poor VPROM case, it was also noted that increasing the viscosity of the sample does not always help for easier swallowing.