Experimental study on flame radiation characteristic from line pool fires of n-heptane fuel in open space

This study experimentally investigated the flame radiation characteristic of line pool fires in open space. The n-heptane line fires burning in the pools with different aspect ratios of length to width (n) were conducted. The mass loss rate (MLR), radiation distribution (along the flame plane), and radiant fraction are investigated by using wide-view-angle and slit radiometers. Combined with a weighted multiple-point source (WMP) model, a radiant fraction of line pool fire can be derived based on the radiation distribution in a novel way. The results show that MLR rises with increasing n at different increase rate (d(m) over dot/dn) and an obvious bifurcation phenomenon occurs when w = 5 cm, the line pool fires transform into violent turbulent combustion from steady laminar. It is also found that with the increase of n, radiant fraction of line pool fire increases for various w due to the more asymmetric air entrainment and stronger turbulence degree, whose range is 0.28-0.37. A new multi-cylinder flame model has also been proposed for flame radiant fraction calculation, and the errors of results are within a certain degree compared with data calculated by the WMP model. (C) 2020 Elsevier Ltd. All rights reserved.