Precursor flame characteristics of flame spread over aviation fuel

Research on flame spreading over liquids is indispensable to make a fire risk assessment of large-sized pool fires in their incipient stages. This precursor flame that is a unique behavior for flame spread over hydrocarbon oils is still not exhaustively understood. A series of tests on flame spread over aviation fuel of RP-5 is well designed and conducted by using a high-speed camera, an infrared camera and several high-sensitive thermocouples. Pulsating performance, spreading velocity, and temperature distribution of this flame are achieved and compared with previous hypotheses. The controlling mechanism of precursor flame is interpreted by coupling effects of gas- and liquid-phase flows in flame spread. The pulsation frequency is qualitatively predicted by Fick's second law and Raoult partial pressure law. The precursor flame attribute is achieved according to spreading velocity. This precursor flame velocity synchronously illustrates that hydrocarbon fuel spilling is potentially more hazardous than alcohol fuel owing to significant large speed of precursor flame. The precursor flame propagation is directly related to liquid surface temperature, hence, spatial temperature distribution near oil surface is revealed. The results of this study will help us understand hydrocarbon spilling fires and possess implications on fire protection design of such flames. (C) 2017 Elsevier Ltd. All rights reserved.