Mathematical modelling of LPG tanks subjected to full and partial fire engulfment

Abstract

SUMMARYThis paper describes the use of field and zone modelling techniques in studying the behaviour of LPG tanks when subjected to accidental fire conditions. The field modelling approach is used to determine the free convective flows and heat transfer in both the vapour and the liquid regions, and also the heat transfer through the tank wall. Zone modelling techniques are employed to calculate the fire heat flux and the radiation heat transfer from the vapour wetted wall to the liquid/vapour interface. The model is verified by comparing predicted results with full scale experimental data obtained by the Health and Safety Executive, U.K. ' The comparisons indicate that the model can accurately predict the tank pressure and time to first valve opening. The model is used to investigate the effect of fire exposure level on the tank behaviour.

The boiling liquid expanding vapour explosion (BLEVE): Mechanism, consequence assessment, management

“…It has been surmised [68][69][70] that when a fire engulfs a PLG tank, the liquid near the wall is heated, becomes less dense and rises to the top, rendering the liquid thermally stratified. As this top liquid dictates the tank pressure, the actual tank pressure in such a situation would be higher than the one expected from the average liquid temperature.…”

A simplified model to predict the thermal response of PLG and its influence on BLEVE

“…(12) is only suitable for the PLG being uniformly heated. However, under some circumstances, the maximum temperature difference can reach 20 K [10]. So stratification should be considered.…”

“…So a BLEVE is severely affected by the mass and the temperature of the loading. Many researchers have studied the mechanism of BLEVE [2][3][4][5][6][7][8][9][10][11].…”

Fire Dynamics and Solar Heating Influence on an Oval-Shaped Chemical Tank Lorry

“…Although few studies have been done on the thermal response models of cylindrical horizontal storage tanks, little attention has been devoted to the tanks with the oval shape. Many investigators have proposed mathematical models describing the thermal response of cylindrical horizontal LPG tanks, − yet the simulation concepts and approaches were not identical. While Ramskill 2 left out the important differential equations in his lumped-parameter model because of trade secrets and proprietary information, Beynon and co-workers 3 used a distributed-parameter approach.…”

“…Aydemir and co-workers 4 also used a lumped approach for the tank content with two control volumes linked by the evaporation of a stratified interface. Hadjisophocleous and co-workers 5 used field and zone modeling techniques in studying the behavior of liquefied petroleum gas (LPG) tanks when subjected to accidental fire conditions. Thermal radiation hazard and assessment of safety spacing between tanks were discussed by Chen and coworkers 6 in addition to a description of a detailed thermal response model.…”