CFD simulation of pressurised metered-does inhaler (pMDI)

Pressurised metered dose inhalers (pMDI) are the most widely used aerosol delivery devices to treat asthma and COPD due to its unique ability to produce numerous inhalable droplets. However the mechanism leading to droplet generation is elusive, mainly due to small length scales and short time scale, causing experimental difficulties to obtain flow information. Such lack of insight has - to date - limited predictive capability of theoretical approaches and impeded device optimisation. The main aim of this research is to improve understanding of the thermo-fluid dynamic processes leading to droplet generation by constructing validated numerical models to predict pMDI aerosol characteristics as a function of device geometry and formulation composition. The thesis presents a systematic study of existing two-phase flow models to predict the flow conditions and the rate of propellant flow through a pMDI actuator: the homogeneous equilibrium model (HEM), the slip equilibrium model (SEM) and the homogeneous frozen model (HFM). [Continues.]