A model for radiation evaluation and cooling system design in case of fire in tank farms

摘要

The effects on surrounding tanks of the heat radiated by a pool fire occurring over a storage tank of liquid hydrocarbons are studied by means of a solid flame model. The irradiation to the surroundings is calculated with a set of empirical correlations for flame parameters and by means of a complete 3D view factor model, implemented in a self-built code, which solves the view factor problem regarding the infinitesimal surfaces that describe the source and target surfaces. The calculation of irradiation on target surfaces is then applied to evaluate the local and overall amount of cooling water needed to prevent the fire from propagating to the surroundings. The cooling water, which protects the tanks facing the flame, is expected to be distributed as a film moving downward from a pipe around the top of the vessel, while tank top is equipped with foam systems. Once validated in terms of available literature data, the present model is applied to a series of test cases regarding different separation distances between tanks in order to evaluate the mass flow rates of water needed for cooling the target tank side for a variety of operating conditions.