Computational fluid dynamics studies on the effectiveness of sidewall sprinklers to suppress the fire at the undercarriage of mass rapid transit train

Abstract

This paper reports the computational fluid dynamics (CFD) studies of sidewall automatic fire sprinklers installed adjacent to and in close proximity to the trains to suppress the fire at the undercarriage of the trains in the stabling yard, for the sake of protection of the train assets. Plume cooling due to water spray from fast response sprinklers is simulated with the sprinkler model available in Fire Dynamics Simulator (FDS). Concurrently, fire suppression due to the interaction between the water and fire source is simply modelled with the assumption of an exponential reduction of the prescribed burning/pyrolysis rate. The objective is to gain some insight about the effectiveness of sidewall sprinklers proposed to prevent the fire from spreading to adjacent trains. CFD simulation results demonstrate that it is highly likely that the undercarriage fire will spread to both the connected train-car and its adjacent train, if only overhead sprinklers are provided in the design. Due to the obstruction posed by the train, water cannot reach the fire source. Sidewall sprinklers are very effective to detect, control, suppress and even extinguish the fire, hence preventing the spread of fire. When sidewall sprinklers are installed on both sides of the trains, further asset protection may be extended successfully to the connected train cars. This study implies that the installation of sidewall sprinklers may be a practical solution for the protection of train assets in the stabling yard.