Flame heat fluxes and correlations of upward flame spread along vertical cylinders in various oxygen environments

TLDR: In this paper, the authors verify theoretical dimensionless correlations for upward fire spread and determine heat fluxes on a vertical cylinder burning in various oxygen environments, using a flame spread theory, developed and verified for single-wall fires.

Abstract: The objectives of this work are to verify theoretical dimensionless correlations for upward fire spread and determine heat fluxes on a vertical cylinder burning in various oxygen environments. A flame spread theory, developed and verified for single-wall fires, provides (1) a relation between normalized pyrolysis front and normalized time starting from the beginning of the fire spread process and (2) a relation between flame height and pyrolysis length. These relations are used to analyze experimental upward fire spread data on clear poly(methyl methacrylate) (PMMA) cylinders. Experiments, reported elsewhere, were run in a flammability apparatus under well-ventilated conditions for fire spreading along clear PMMA vertical cylinders 0.025 m in diameter and 0.61 m high at three mass oxygen concentrations of supply air, 0.233, 0.279, and 0.446. The pyrolysis front location and flame heights were measured as function of time. Flame heat fluxes to the surface were not measured in these tests. By comparing the experimental results with the theoretical predictions, the theoretical scaling correlations are verified, and the flame heat fluxes to the cylinder surface are deduced for various oxygen concentrations.