Experimental study and modeling of external heat radiation from a burning oil layer with an embedded obstacle

Accurate assessment of heat radiation from the flame to the environment in fire scenarios can provide critical support for fire suppression. A burning oil layer affected by an embedded obstacle represents a typical flame configuration. This work conducts experiments on a burning oil layer with embedded obstacles of different sizes. Results showed that as the obstacle diameter increases, both the flame height and burning rate decrease. Distribution of the obstacle sidewall temperature is characterized, with a maximum temperature of 630 °C, and the sidewall is covered by soot. A dimensionless formula of flame temperature is established. The weights for the radiant heat distribution of point sources are calculated, and a multipoint source radiation model is established to predict the radiation from the flame. Using complex view factors and flame transmittance, a multi-section cylindrical model was established to predict radiation from embedded obstacles. Then, an integrated model for total external heat radiation from a burning oil layer under the influence of the embedded obstacle is developed. Comparisons with point source, multipoint source, and solid radiation models demonstrate that the model developed in this work exhibits the highest accuracy. When the obstacle height is comparable to or exceeds the height of the continuous flame zone, the proportion of total radiant heat contributed by external radiation from the obstacle can reach approximately 30%. When the obstacle height is relatively low compared with the continuous flame zone, this proportion is below 10%. This highlights the radiation from the embedded obstacle is nonnegligible when evaluating the radiant heat received by adjacent equipment or personnel in fire scenarios. This work presents a method for calculating external heat radiation affected by an embedded obstacle.