Research on Diffusion Characteristics and Parameters of Artificial Component Air Ventilation in Underground Refuge Chamber

Abstract

The traditional ventilation system of the underground refuge chamber (URC) relies on external ambient air, which may be affected in emergency and has certain limitations. Therefore, this study proposed a self-sufficient artificial component air (ACA) ventilation system to overcome this key issue. Through smoke experiments and computational fluid dynamics (CFD) simulation, the effects of factors such as supply air velocity, temperature, oxygen concentration, and the inlet-to-deflector distance on the diffusion of ACA were analyzed, and the semi-theoretical models were established to describe the descent of the airflow trajectory, the decay of axial velocity and oxygen concentration, which provides a quantitative basis for system design. At the same time, the contribution ratio of indoor oxygen concentration indicated that the ventilation system reaches dynamic equilibrium after 2 minutes of operation. Moreover, the orthogonal experiments and range analysis showed that the supply oxygen concentration is the dominant factor in controlling the oxygen supply efficiency, followed by the supply air temperature, inlet-to-deflector distance, and supply air velocity. The results showed that oxygen concentration of 25%, the airflow velocity of 3.5 m/s, and the inlet-to-deflector distance of 0.1 m achieved the optimal state, ensuring efficient oxygen supply and uniform distribution. This study provides a comprehensive theoretical support and parameter design basis for the ACA ventilation system, and offers a reliable solution for creating a safe and self-sufficient living environment in underground refuge chamber.