Experimental study on the ejected flame behavior and near-field flame radiation characteristics from building compartment with double openings under crosswinds

With the acceleration of urbanization and the densification of high-rise building complexes, the integration of energy systems and the functional complexity of building spaces have led to the uncontrollable combustion within the energy building system. This study investigates the evolution of ejected flame behavior, flow field characteristics, and near-field flame radiation from a building compartment with double openings under crosswind conditions, combining numerical simulation and experimental methods. Experiments were performed using a reduced compartment with double openings of different separation distances. The results show the interaction between the ejected flame from a double-opening compartment, and it reveals three different stages with the variation of HRR and crosswind speed. During the most hazardous stage II, the interaction between the flames including the merging of the flames is analyzed, which can easily cause three-dimensional fires on the building facade, the upstream and downstream flame inclination angles were defined, and a quantitative model for these inclination angles was developed based on effective crosswind speed. Additionally, a quadrangular prismatic flame model was proposed based on the actual flame geometry. The study further analyzes the flame surface area, radiative fraction, and view factor to predict the near-field thermal radiation. In this work, the effect of crosswinds on the flame radiation distribution caused by ejected fires with two openings was studied and discussed, and the interaction mechanism between the two ejected flames from a compartment under crosswinds was revealed, thereby enhancing the understanding of combustion processes and near-field flame radiation characteristics in ejected flames from double openings along the facade.