Segmented Line Heat Source Model for Thermal Radiation Calculation of Jet Fires in Chemical Plants

Abstract

The jet fire caused by the leakage of combustible materials is one of the biggest threats to the safety of chemical plants. Thermal radiation of the jet fire brings severe damage to nearby facilities and people's health. To evaluate the damage of jet fires, a precise model for the calculation of heat radiation is indispensable. Classical thermal radiation models of jet fires either have a lower prediction accuracy or a higher computation complexity. To overcome such deficiencies, this paper proposes a novel segmented line heat source (SLHS) model for jet fires. Because the length of the jet fire is often much larger than the width, the jet fire is viewed as a line heat source, with all the heat radiated from the centerline of the jet fire. The jet fire is divided into three segments along the flame length according to the temperature distribution and thermal radiation characteristics of the flame. Based on the SLHS model, three types of thermal radiation models, called cone-cylinder-cone, ellipsoid-cylinder-ellipsoid and ellipsoid-cylinder-cone models, are built for computing the radiant heat flux distribution around the jet fire. The effectiveness and advantages of the proposed models are illustrated with the experimental data and a numerical simulation.