Laminar flame propagation on a horizontal fuel surface: Verification of classical Emmons solution |
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Authors: | V. Raghavan A. S. Rangwala J. L. Torero |
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Affiliation: | 1. 206 A Thermodynamics and Combustion Engineering Lab, Department of Mechanical Engineering , Indian Institute of Technology Madras , Chennai, 600036, India;2. Department of Fire Protection Engineering , Worcester Polytechnic Institute , 100 Institute Road, Worcester, MA, 01609, USA;3. BRE Trust/RAEng Chair in Fire Safety Engineering, Edinburgh Fire Research Centre, School of Engineering and Electronics , University of Edinburgh , Edinburgh, UK |
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Abstract: | This work analyses the classical Emmons (1956) solution of flat plate laminar flame combustion on a film of liquid fuel. A two-dimensional (2D) numerical model developed for this purpose has been benchmarked with experimental results available in the literature for methanol. In the parametric study, numerical predictions have been compared with Emmons classical solution. The study shows that the Emmons solution is valid in a range of Reynolds numbers where flame anchors near the leading edge of the methanol pool and the combustion zone is confined around the hydrodynamic and thermal boundary layers. However, in cases of low free stream velocities the combustion zone is beyond the boundary layer zone and the Emmons solution deviates. In cases of very high free stream velocities, the flame moves away from the leading edge and anchors at a location downstream. The Emmons solution is not applicable in this case as well. For the fuel considered in this study (methanol), accounting for thermal radiation, employing an optically thin radiation model, allows better agreement between experimental and numerical temperature profiles but does not affect the mass burning rates. |
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Keywords: | Emmons laminar boundary layer diffusion flame methanol combustion B-number Damkohler number |
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