Role of Pressure Gradient and Porosity Parameter in Enhancing Mucus Transport in Lung Airways

Abstract

In this paper, a two-layer unsteady state planar mathematical model is proposed to study mucus transport in human lung airways by considering mucus as a viscoelastic fluid and serous layer as a Newtonian fluid by taking into account the effect of porosity parameter due to immotile cilia forming porous matrix in the serous sub-layer in contact with the epithelium. The effect of shear stress induced by air-motion due to forced expiration and acceleration due to gravitational force are also considered in the model. It is observed that mucus transport rate increases as the pressure gradient, the shear stress and porosity parameter increase, but it decreases as its viscosity increases. It is also observed that mucus transport rate decreases as the viscosity of serous layer fluid increases, but any increase in mucus viscosity at its higher values does not seem to affect the mucus transport. It is also shown that mucus transport rate decreases as its modulus of elasticity or its density increases. It is also observed that the mucus transport rate decreases as the thickness of serous layer fluid or transport duration increases