Characterization of large LPG pool fires and mucus clearance dynamics in upper airway using CFD method

Abstract

A large pool fire can be generated if there is a liquefied petroleum gas (LPG) leakage during transportation or at storage sites, while the underlying mechanisms of how the hazardous matter can be generated from the LPG pool fire and delivered dose into the human lung, and evaluation of the exposure risks are still ambiguous. Thus, it is necessary to systematically study the LPG pool fire rheology and the generation, transport, and deposition of the generated aerosolized toxicants from the pool fire to the human respiratory system. To partially address the above-mentioned concerns, this study has conducted novel research efforts to investigate the characteristics of large LPG pool fires and cough-driven mucus transport behaviors in upper lung airways, which can be employed to assess the health risks from LPG fires to the pulmonary system future work. Specifically, Chapter I reviewed the previous studies concerning the LPG pool fires and mucus movement behaviors in lung airways using experimental methods and numerical approaches, as well as presented the research objectives. Chapter II was to develop an experimentally validated CFD model to estimate the surface emissive power, and predict the incident radiation from large LPG pool fires to the surrounded objects and develop the reasonable minimum distances between the pool fire and objects using CFD simulations. Chapter III performed numerical simulations using an experimentally validated CFD model to simulate large LPG pool fires and predict the fire configuration characteristics, including flame height and flame tilt. The impacts of pool diameter and wind velocity on the fire configuration characteristics were investigated. Based on the CFD results and the parametric analysis, new correlations are proposed to provide more accurate estimations of flame height and tilt specifically for large LPG pool fires. Chapter IV has built an experimentally validated Volume of Fluid (VOF) model to conduct a quantitative analysis to investigate the effects of cough intensity and initial mucus thicknesses on the mucus transport and clearance in a mouth-to-trachea airway geometry. The VOF model developed in this work can be further refined and integrated with Discrete Phase Models (DPMs) to predict the mucus clearance effect on inhaled toxic particles from LPG pool fires explicitly. In addition, Chapter V summarized the essentials of the research work done and outlined the future work.