Critical Conditions for Fire-Induced Smoke Confinement by Air Curtain in Long Channels

The air curtain can be adopted to slow down or stop smoke spread, in case of channel fires, with no influence of the normal usage of the channels and on the human evacuation. The flow field of air curtain jet from ceiling to floor was divided into 3 sections, i.e. the section of impinging mixing, non-isothermal jet and impinging floor and the theoretical analysis of fire-induced smoke control by air curtain in long channels was carried out. The formulas of the critical conditions for absolutely preventing smoke from intruding the protected side were obtained. With the Realizable k–ε model and the numerical solutions of the formulas as the initial and boundary conditions, an application example was simulated. Results showed that the three-section analysis method was reasonable and the simulated results verified the rationality of the theoretical prediction model.