Design of Medical Devices Involving Multi-disciplinary Processes and Based on Fundamental Physical Principles

Abstract

This dissertation focuses on the optimal design of medical devices through the use of numerical simulation and the utilization of first principles of the participating phenomena. Through three broadly ranging case studies, the dissertation explores a wide variety of physical phenomena found within medical devices and in other applications. Pressure drop and sound generation are the primary focii of the leading case study which constitutes the first-ever analysis of the fluid mechanics of a therapeutic device for the treatment of cystic fibrosis. The treatment utilizes a time varying pressure that acts on the abdomen of the patient in order to break up masses of mucus. The second study is the first known effort to design peristaltic pumps using the principles of fluid-structure interaction. The time-dependent mechanics of peristaltic pumping were utilized to determine the deformations and pressures in the flexible-walled plastic tubing. The change of volume of the tubing serves to propel a liquid contained within the tube. Finally, the third study investigates the fluid mechanics and heat transfer mechanisms found in an enhanced-surface fluid warming device. The key analysis and design tools used throughout the aforementioned case studies of this dissertation are physical model formulation adapted to computational fluid dynamics (CFD), the theory of turbulence-based sound generation, Ogden’s hyperelastic model of polymeric materials, and the theory of heat transfer. The fluid flow phenomena dealt with in this work include three-dimensional, unsteady, laminar and turbulent flows. Heat transfer concepts utilized include conduction within both fluids and solids, advection within interacting parallel flow regions, and the theory of heat transfer enhancement. Each chapter contains multiple results pertaining to the device in question. These results serve to expand the reader’s knowledge of the underlying physical processes which control the function and effectiveness of the medical device.