Limiting Distances for Flame Merging of Multiple n-Heptane and Di-tert-Butyl Peroxide Pool Fires

Abstract

Experiments to determine the limiting distances for flame merging of multiple pool fires are presented. As model substances n-heptane and di-tert-butyl peroxide are used. Laboratory scale tests with a diameter d = 6 cm and relative distances between the pools of 0.08 = D/d = 4 are described and complemented with field experiments with a diameter d = 1.5 m and relative distances between the pools of 0.17 = D/d = 1. Three regions for flame merging are observed and limiting distances are determined. A merging region with the limiting distance D_merg/d within which all flames merge together over the complete burning time. A transition region with the limiting distance D_tran/d within which some flames merge together while other flames are separated from each other. A separated region within which all flames are completely separated from each other. A correlation against the number of burning pools is presented to predict the limiting distances D_merg/d und D_tran/d.