Modeling an Ascending Flow over a Burning Oil Spill

Abstract

A significant number of emergencies that occur in the chemical, process, and transportation industries begin with accidental spillage and ignition of combus-tible liquids. In such cases a special danger is the spread of fire to adjacent sites. As a rule, only the radiant heat transfer from the fire is taken into account when developing fire-fighting measures for combustible liquids storage facilities. How-ever, in some cases, the convection component of the heat flux can make a signif-icant contribution to the overall heat transfer. Ignoring it can lead to an incorrect safety assessment of an industrial facility. This paper proposes a model of the velocity and temperature distribution in the plume above a spill fire. The model is based on the Navier-Stokes equation and is a nonlinear second order parabolic differential equation. The properties of the combustion center determine the first-type boundary condition. The spillage of flammable liquid can have any shape. The presence of wind is taken into account by introducing a constant horizontal component of the flow velocity. The finite difference method is used to numeri-cally solve the equation. The dependence of kinematic viscosity on the flow tem-perature is taken into account. An empirical relationship is used for correlation between temperature and velocity. It is shown that the presence of wind inclines the ascending flow. The angle of inclination is not constant and increases with distance from the combustion center due to the decrease in velocity and cooling of the flow.