Моделювання теплового впливу пожежі в резервуарі з нафтопродуктом на сусідній резервуар

Abstract

The forecasting of the consequences of emergencies caused by the fire of a vertical steel tank with oil product in the tank group is considered. Due to the thermal impact of the fire on the next tanks, there is a threat of cascading fire.. Assumptions based on the model of heating the tank shell under the thermal influence of a fire in the adjacent tank are substantiated. This model is a differential equation that describes the process of heat transfer inside the tank shell, with boundary conditions on the outer and inner surfaces of the shell. These boundary conditions describe the heat exchange of the shell surfaces with the torch, the environment and the vapor-air mixture in the gas space of the tank. The model takes into account heat exchange by radiation and convection. An estimation of the value of the mutual irradiation coefficient with a torch for an arbitrary point on the tank shell is obtained. It is shown that after transition to dimensionless coordinates the value of the irradiation coefficient for all tanks with a capacity of up to 20000 m3 depends only on the type of liquid – flammable or highly flammable. An estimation of the convective heat transfer coefficient under free convection conditions with ambient air for the outer surface of the tank shell and with a vapor-air mixture in the gas space of the tank for the inner shell surface is obtained. The estimation is obtained by using the methods of similarity theory. Numerical solution of the heat balance equation for the tank shell allows finding the temperature distribution on the shell at an arbitrary time. This allows determining the area on the tank shell that needs cooling and determining the time limit of its onset. It is shown that within 5 minutes after the start of the fire, the temperature of the part of the adjacent tank shell that facing the fire reaches dangerous values.