A Multiphase Analysis of Liquid Plug Deposition Inside the Simplified Respiratory Air Tubes

Abstract

This work analyzes the deposition and spread efficacy of drug-loaded liquid bolus, which is displaced downstream using a fully developed velocity inlet inside the liquid-lined cylindrical airways. The dimensions of the cylindrical tube are chosen as per Weibel’s model [1] of airways at 7 generations, and the thickness of the annular liquid lining is varied from 0.07R to 0.13R to account for the different lung conditions of COVID-19 patients. The current approach is motivated by the fact that the SARS-CoV-2 virus that causes COVID-19 initially stays along the lower generations of airways before binding with the alveolar epithelial type-II cells to infect the human body. Therefore, they must be neutralized immediately using a high dose of antiviral drugs deposited as a liquid plug. Further, an in-house developed incompressible multiphase solver is used to track the evolution and deposition of the initially instilled liquid plug inside the cylindrical tube. The results suggest that a cut-off velocity exists for each film thickness below which the successful deposition and rupture of the liquid plug are not possible. Additionally, the rupture time increases with an increase in liquid film thickness.