Experimental study on ceiling smoke temperature distributions in near field of pool fires in the subway train

Several existing studies have been performed on the fire characteristics of traditional tunnel and enclosure models; however, these findings may not be applicable to a subway train with a special confined structure. Therefore, to investigate the smoke temperature distributions under conditions involving different fire locations and door statuses, a set of experiments were conducted by using a reduced-scale subway train model. The results indicated that the longitudinal and transverse temperature distributions correspond to the exponential decay law, although the transverse temperature does not exhibit a regular distribution under certain conditions. Furthermore, the previously developed empirical models were not applicable to the subway train considered in this work. Consequently, empirical models similar to those involving the exponential function were developed to predict both the longitudinal and transverse smoke temperature distributions. The corresponding results exhibited a reasonable fit with the experimental data. The powers of the exponential functions were noted to be proportional to the dimensionless heat release rate, with values of 0.4 and 0.3 for the longitudinal and transverse smoke temperature distributions, respectively. The research findings and empirical models provide a reference for the fire risk assessment of subway train or other similar frameworks.