Reduced-scale experimental study of the temperature field and smoke development of the bus bar corridor fire in the underground hydraulic machinery plant

•Reduced-scale (1:12) experiments are conducted in an underground bus bar corridor.•Parameters used in numerical simulation were validated based on the experiments.•More fire scenarios analyses are realized in the numerical simulation.•The smoke spreading with natural filling in the underground space is provided.

While fire once occurs in a long tunnel, both heat and toxic smoke will be continuously released and become the fatal factors threatening the indoor occupants. This paper mainly studied the characteristics of smoke in the reduced-scale (1:12) corridor model under the natural filling condition. The temperature distribution of the fire-induced smoke and the smoke layer height are tested. The test data are used to access the temperature field for different heat release rates (HRRs) without ventilation in the corridor. The maximum smoke temperatures under the ceiling are all lower than 200 °C for HRR less than 1500 kW. The smoke temperature stratifies vertically. The stratification can be described by the exponential fit. Besides the temperature field, the smoke layer height is also recorded. Smoke sinks quickly after the ignition. 60 percent of the space has been filled of smoke by the dimensionless time of 300. Then the smoke slows down gradually. In order to achieve more results with different working conditions, full-scale numerical simulation is conducted. There is a good agreement between the reduced-scale experimental and predicted results for the temperature and the smoke layer height, respectively. These provide the basic data of fire scenario in the bus bar corridor. It also affords to predict the smoke development in other underground corridors.