In this paper, we present a ‘simplified’ approach for the numerical modelling of the convective currents that occur within a liquid fuel in the case of a pool fire and which are induced by in-depth thermal radiation. This approach is based on the concept of ‘effective’ thermal conductivity, which is calculated herein based on the analytical solution of a steady-state one-dimensional heat conduction equation including a source term for in-depth radiation. This solution leads to a temperature profile which displays a horizontal liquid layer (of a given depth) that is bounded by a temperature that is higher at its bottom than its top. This thermal structure generates Rayleigh-Bénard instabilities which enhance heat transfer within the liquid. This effect is modeled via an increase of the ‘actual’ thermal conductivity of the liquid by a dimensionless heat transfer number, namely the Nusselt number. The Nusselt number is calculated based on the ‘classical expression’ of the Rayleigh number for the case of a ‘horizontal cavity heated from below’. The paper provides the details of the derived solution for the ‘effective’ thermal conductivity along with examples of application to several fuels.

International Seminar on Fire and Explosion Hazards (9; 2019; Saint Petersburg, Russia). Proceedings of the Ninth International Seminar on Fire and Explosion Hazards [Электронный ресурс]: 21-26 April 2019, Saint Petersburg, Russia. Vol. 1 / Peter the Great St. Petersburg Polytechnic University, Autonomous Non-Profit Organization "Fire and Explosion Safety", Gefest Holding Ltd ; [edited by A. Snegirev [et al.]. — Электрон. текстовые дан. (1 файл : 118 Мб). — Saint Petersburg, 2019. — Загл. с титул. экрана. — Свободный доступ из сети Интернет (чтение, печать, копирование). — Adobe Acrobat Reader 7.0. — <URL:http://elib.spbstu.ru/dl/2/k19-45.pdf>. — <URL:http://doi.org/10.18720/SPBPU/2/k19-45>.