Dynamic evolution behaviors and heat feedback characteristics in the co-burning of a large-area dike fire and multiple tank fires

The co-burning of multiple tank fires and dike fire is a typical fire phenomenon in massive fire accidents, which involved intricate heat and mass transfer processes. This study aims to investigate the dynamic evolution behaviors and explore the heat feedback characteristics exhibited by co-burning fires. A series of co-burning fires (CBFs) experiments with different tank spacings were conducted. For comparison, the experiments of double tank fires (DTFs) and dike fire (DF) were also conducted. The flame morphology of CBFs shows that the burning process can be divided into four stages, i.e., elevated and ground fire of initial stage, boiling over stage, quasi-stable co-burning stage, and extinguishing stage. During the quasi-stable stage, the fuel of the tank is in film boiling. And the mass loss rate of the tank increases sharply accompanied by flame lift-off compared with discrete double tank fires. It indicates that the heat feedback enhancement plays a dominant role due to the direct heating of sidewall by the dike fire. The analysis of heat feedback reveals that the mode of heat conduction changes and the dominated heat feedback for CBFs has shifted from radiation to conduction compared with DTFs, accounting for about 65 % of the total heat feedback.