Response to fire of pressure vessels for the storage and transportation of hazardous materials
Bradley, Ian Michael
Pressure vessels present a serious hazard when exposed to fires. Boiling liquid expanding vapour explosions (BLEVEs) and other associated vessel failure events are known to have significant consequences, and be key propagators of industrial accident scenarios. Understanding the response of pressure vessels to fire, and especially the rate of pressurisation, remains a significant challenge. This study reviews the ability of existing models to capture the physical processes that drive vessel pressurisation, and the existing fire test evidence used to validate such models. The scope of existing test evidence is found to be inadequate to validate complex numerical models. This study defines and describes a set of test conditions and a novel piece of experimental apparatus that can provide detailed and reproducible test evidence in an economic manner for the purpose of numerical model validation. The equipment included a 2.6 m3 vessel with a full cross-section (Ø1 m) glass window. A pressure compensation system maintained the window integrity, allowing combined temperature and velocity field measurements, using thermocouples and particle imaging velocimetry (PIV), to be made during fire exposure. Initial studies using ANSYS CFX indicate that the Eulerian-Eulerian multiphase model and the RPI wall boiling model are capable, when used together, of providing a good basis for simulation of the pressurisation rate, given the use of appropriate bubble-related parameters obtained by experiment.