Numerical simulation of thermal response behavior of floating-roof tanks exposed to pool fire

Abstract

In industrial plants, the fire spread of separative fuel tanks could be related to the tank rupture caused by the thermal radiation from nearby fires. The present paper develops a theoretical framework for analyzing the thermal response behavior and failure time of floating-roof atmospheric storage tanks when exposed to a pool fire. Multi-layer cylindrical flame radiation model is used to predict the radiant heat flux field on the surface of tanks. This radiant heat, considered as the thermal load for a finite element analysis (FEA), influences the tank transient response under thermo-mechanical coupling effects. The paper investigates the respective and combined effects of the tank thermo-physical properties, the non-uniform radiant heat flux distribution, the generated stress as well as the failure time of target tank. For comparative purposes, an empty tank is used as a reference. The results show that the empty and full-filled storage tanks differ in their thermal response modes and their thermos-mechanical behaviors. Within the values in the temperature range of interest adopted for the tank thermo-physical properties, their variations with the temperature have little influence on the tanks’ behavior. The non-uniform radiant heat along the vertical and around circumferential directions of tank has a significant effect on the tanks’ behavior. The stored liquid mediums considerably affect the tanks’ behavior. The failure time of empty tank is over three times as long as that of full-filled storage tank.