pratibha

The respiratory system undergoes various physiological and immunological changes with age. After birth, alveolization is one of the main factor associated with progressive growth of lung, which is relatively poorly analysed in respect of lung function. In this study we considered growth of lung caused by progressive increment in number of alveoli and simultaneously calculated its effect on airflow dynamics and filtration efficiency of human lung from childhood to age of 30. Incorporating the idea of filtration through lung with respect to age biofilter model is used by assuming porosity of lung varied with respect to number of alveoli and their surface area. Transportation and deposition properties of nanoparticles of various shapes during inhalation is taken under consideration by using particle shape factor. Generalized Navier Stokes equation is used for flow dynamics and finite difference scheme is used to solve the problem numerically. Simulation is done by using user defined code on MATLAB at very fine grid. Results indicate that the filtration efficiency of lung decreases as age increases from childhood to age of 30; additionally, nonspherical nanoparticles with high aspect ratio’s will take a longer time to be filterd from lung as compared to spherical nanoparticles of the same diameter.

Airway mucus is difficult to clear and to improve lung function clearance of mucus is necessary. The deep coughing, chest physiotherapy, high frequency chest wall oscillation etc. are some of the best methods to clear excessive mucus from lung airways. In this article we analysed the behavior of fluid flow between parallel walls , where both walls are porous and the flow is induced by the oscillation of these walls and pressure gradient; which is applicable for clearance of mucus from lung airways. Generalized couette flow is applicable to model the oscillation of parallel walls, however the laminar flow of viscous fluid is taken under consideration. The generalized Navier-Stokes equations are applied to make various hypotheses and finite difference scheme is used to solve the problem numerically. Effect of wall oscillation, wall porosity, pressure due to porous media on mucus clearance and particle aspect ratio on the deposition of nonspherical nanoparticles are analysed graphycally after simulating the problem on MATLAB R2013a by user defind code. Simulation show an excellent agreement of unsteady flow of viscous fluid at large values of time and significant correlation between pressure gradient and porosity of walls, frequency of wall oscillation and their imapct on mucus clearance are obtained. In addion it is observed that fluid and particle velocity are increased with the enhancement of media porosity, breathing frequency and aspect ratio. The aim of this paper is to study the influence of wall movement, wall porosity, pressure on wall, wall oscillating frequency on the clearance of mucus from lung airways.