CFD Heat Transfer Simulation of the Human upper Respiratory Tract for Oronasal Breathing Condition

Injuries due to inhalation of hot gas is commonly encountered when dealing with fire and combustible material posing a threat to the human life. Various studies have been carried out in the literature investigating the heat and mass transfer characteristics in the human respiratory tract. 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 a CFD software to study the temperature profile through the upper human respiratory tract consisting of nasal, oral, trachea and the first two generations of bronchi. The model developed is for the simultaneous oronasal breathing during the inspiration phase with high volumetric flow rate of 90 liters/minute and the inspired air temperature being 100 degrees Centigrade. The geometric model depicting the upper human respiratory tract 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. The temperature distribution can be utilized in the design of the respirator systems where the inlet temperature is regulated favoring the human body conditions.