Internal Explosion Load Computation and Structural Response of Storage Tank Based on Heat-Fluid-Solid Coupling

Storage tanks are usually used for the storage of various inflammable and explosive media. When the concentration of inflammable gases volatilized from the media in the tank lies in the range between the lower and upper explosive limits, combustion and explosion are very likely to happen under the condition of accidental ignition. The storage tank will be damaged by the explosion-generated overpressure and temperature rise. Here, starting from the perspective of inflammable gas combustion and explosion accidents within the storage tank, the internal explosion load and structural dynamic response of the storage tank were characterized. Radiative heat transfer following combustion and explosion of the inflammable gases and the heat transfer process within the tank structure were considered. The computational fluid dynamics method was used to build the numerical computational model depicting the combustion process of inflammable gases within the tank. Simulation and comparison with the experimental results were then conducted for a small-sized storage tank, which verified the accuracy of the numerical model. Based on heat-fluid-solid coupling, the problems of fluid-solid coupling and coupled heat transfer during internal explosion of inflammable gases within the tank were investigated. The temperature rise pattern and overpressure load distribution of the shells as well as the structural response of tank structure were characterized. The results showed that strain rate hardening and temperature softening of the storage tank material caused by internal explosion pressure and radiant heat were two primary reasons for structural stress. Due to inconsistent radial deformation of the roof and shells, considerable stress concentration occurred at the roof-to-shell connection. This was where failure of the storage tank was most likely to happen.