Study on the evolution of flame morphology and burning rate of pool fires under the combined influence of crosswind and ullage height

Pool fires with varying ullage heights under windy conditions represent critical scenarios in tank fire incidents, posing significant challenges to the energy storage and utilization safety. This study investigates the behavior of pool fires with different ullage heights subjected to varying crosswind velocities, focusing on flame morphology, radiative heat feedback, and burning rates. Experimental results reveal that during the steady burning phase, flame morphology parameters—such as down-reaching flame retraction length and back-dragging length, down-reaching flame tilt degree, upper flame height, and upper flame tilt angle—demonstrate non-monotonic variations in response to changes in crosswind speed and ullage height, underscoring the complex nature of fire behavior. By applying dimensionless analysis, predictive correlations were established for down-reaching and upper flame tilt angles. Furthermore, variations in down-reaching flame morphology were found to significantly influence radiative heat feedback and associated burning rates, which exhibit complex dependencies on both crosswind velocity and ullage height. Insights from flame morphology and heat transfer mechanisms were used to refine existing burning rate models. These findings can provide valuable insights for optimizing fire prevention and energy storage strategies nowadays.