Experimental study on the characteristics of buoyancy-driven turbulent flame generated by rectangular fire sources with different length–width ratios in an open space

Abstract Fires caused by fuel leakage pose serious hazards to the city’s environment and safety. Different leakage conditions will lead to different shapes of fire sources and produce different hazards to the surrounding environment. To study the characteristics of rectangular fires, this paper conducted experimental studies on rectangular burners with different length–width ratios (n) in an open space. Propane was used as fuel. This study provides for the first time both primary data and new relationships for the temperature and velocity distribution of the flame on the horizontal section at different heights. When the heat release rate is constant, the plume mass flow rate on the horizontal section at the same height increases with the increase of the n. The expressions of temperature and velocity along the rectangular fire centerline are proposed. The empirical equations for calculating the Gaussian half-width of the square and rectangular fire plumes are presented. Finally, combining the expressions above, the correlations of flame mass flow rates in continuous and intermittent flame regions are derived and the calculated values are compared with the experimental data. It is found that the error range is less than 15%. This work can be used to predict the combustion characteristics of buoyancy-driven turbulent flames formed by gaseous fuel. It plays a guiding role in the risk assessment of the gaseous fuel transportation systems. Experimental data and related conclusions also provide important reference data and theoretical support for computational fluid dynamics (CFD) models.