Evaluation of air curtain and emergency exhaust system for smoke confinement of an enclosure

Abstract

This paper analyses the various configuration for the emergency ventilation system consisting of an air curtain and exhaust fan to manage the dispersion of heat and toxicity inside an enclosure for different fire scenarios. Employing this ventilation system is helpful to secure an escape route or extinguishing the fire. The air curtain discharge velocity is 10, 18, and 30 m/s and its discharge angle is set to be 0°,15°, and 30°. Three values of 0.5, 1, and 2m3/s are considered for the exhaust flow rate. Computational Fluid Dynamics simulations have been conducted with a steady laminar flamelet model and buoyant standard k−ε turbulence model to assess the performance of the air curtain and emergency exhaust system for smoke confinement. Evaluation of an optimized state of the emergency ventilation system is provided by the Taguchi method due to computational limitations in solving various cases for the ventilation system configuration. Results show that for each location and heat release rate of fire, it is possible to manage heat, CO, and CO2 dispersion with the adjustment air curtain parameters and emergency exhaust system. Finally, the optimum state of the system is reported for each scenario, and the temperature and concentration of toxic gas have been compared. Results show that for the 200 kW fire, 2 m3/s exhaust flow rate with air curtain discharge velocity of 18 m/s and 15° would be adequate. However, 500 kW fire requires 30 m/s with 30° discharge velocity to contain the fire inside the compartment.