doi:10.3850/978-981-08-7724-8_04-05

ABSTRACT

Most of the current jet fire models used in the accidental fire risks department are semiempirical. They depend on experimental data and are limited to the experimentally studied fire. Moreover, they are not applicable to very large scales (flame length > 100 m) and tend to overestimate large-scale radiation effects. Therefore, predicting accurately the large-scale jet fires radiation effects is today a challenge in a context where the optimisation of industrial site dimensions is at stake. A 1D model based on physical laws has been developed by INERIS for predicting the flame shape and radiation field for large-scale gas or liquid released jet fires. This model is not based on an experimental correlation but takes into account the physical laws like energy balance, momentum balance through an iterative method. Moreover, the model includes the buoyancy forces which gives bent shape to the horizontal or lifted flame and takes into account wind velocity according to the release direction. At a small-scale, good agreement was noticed, first, between the new model predictions and experimental measurements and, second, between the new model predictions and the semi-empirical model results. We expect the agreement to be equally good for a large scale jet fire. Large scale experiments will be carried out in the near future to validate this physical approach.

Keywords: Jet fire, Thermal radiation, Buoyancy forces.

© 2011 CPD Unit, University of Leeds