호흡주기 동안 방독면 내 호흡저항 및 내부 온도 변화에 대한 수치해석 연구

Abstract

We perform numerical simulations of unsteady thermal flows inside a gas mask. Time-dependent respiratory profiles for normal and heavy breathing conditions are imposed at two different inlets, depending on the exhalation and inhalation periods. We assess the respiration resistance (pressure drops) and the regional averaged temperature, considering the effects of nosecup in the gas mask. Simulation results show that the nosecup significantly reduces the exhaled hot airflows to the eye area, reducing the temperature to approximately 26.5°C. In contrast, the maximum of the averaged temperature inside the nosecup is increased by less than 3.6°C during the exhalation period. Under normal and heavy breathing conditions, the nosecup-induced pressure drops during inhalation are approximately 4 Pa and 20 Pa, respectively. However, the induced pressure drops are relatively small than expected from an air purification filter. Thus, the results imply that the nosecup can improve visibility by reducing condensation near the goggles while it can slightly worsen breathing and thermal comfort.