CFD heat transfer simulation of the human upper respiratory tract for oronasal breathing condition

Abstract

Injuries due to inhalation of hot gas are commonly encountered when dealing with fire and combustible material, which is harmful and threatens human life. In the literature, various studies have been conducted to investigate heat and mass transfer characteristics in the human respiratory tract (HRT). This study focuses on assessing the injury taking place in the upper human respiratory tract and identifying acute tissue damage, based on level of exposure. A three-dimensional heat transfer simulation is performed using Computational Fluid Dynamics (CFD) software to study the temperature profile through the upper HRT consisting of the nasal cavity, oral cavity, trachea, and the first two generations of bronchi. The model developed is for the simultaneous oronasal breathing during the inspiration phase with a high volumetric flow rate of 90 liters/minute and the inspired air temperature of 100 degrees Celsius. The geometric model depicting the upper HRT is generated based on the data available and literature cited. The results of the simulation give the temperature distribution along the center and the surface tissue of the respiratory tract. This temperature distribution will help to assess the level of damage induced in the upper respiratory tract and appropriate treatment for the damage. A comparison of nasal breathing, oral breathing, and oronasal breathing is performed. Temperature distribution can be utilized in the design of the respirator systems where inlet temperature is regulated favoring the human body conditions.

A novel modelling approach to energy transport in a respiratory system

“…29,30 For much more comprehensive and detailed study, a full 3-dimensional model may be used. A fully 3-dimensional model of the entire respiratory tract is extremely complex to build and thus many authors have only focused on the upper part of the respiratory tract [31][32][33][34][35] although comprehensive lower airway models have been recently investigated. 36,37 While 1-dimensional fluid-structure interaction model can give a better result than the lumped models and the 3-dimensional models can give every details of the flow, both these approaches can be extremely difficult to implement to capture the details.…”