A Numerical Study of Leading Edge Anchoring Characteristics of Ethanol Sourced Laminar Boundary Layer Diffusion Flames

• Published in: Combustion science and technology Vol. 183; no. 10; pp. 1133 - 1145
• Main Authors: Sahu, Vaibhav Kumar, Ali, Seik Mansoor, Raghavan, Vasudevan
• Format: Journal Article
• Language: English
• Published: New York Taylor & Francis Group 01.10.2011; Taylor & Francis Ltd
• Subjects: Air flow; Anchoring; Boundary layer; Boundary layer flames; Convective extinction; Diffusion flames; Ethanol; Ethyl alcohol; Flame anchoring; Fuel burning rate; Fuels; Leading edges; Mathematical models; Movement; Numerical analysis; Oxidation; Radiation
• ISSN: 0010-2202; 1563-521X
• DOI: 10.1080/00102202.2011.584332

A numerical study of leading edge anchoring characteristics of diffusion flames established over a liquid ethanol film in a confined environment at atmospheric pressure under normal gravity with a forced air flow parallel to its surface is presented. A numerical model, which solves the transient, two-dimensional, gas-phase governing conservation equations with proper interface coupling conditions, is employed. The model uses a global single-step reaction for ethanol-air oxidation to model the finite rate chemical kinetics and an optically thin radiation model to account for thermal radiation losses by absorbing species in a nonluminous flame. Validation of the numerical model is carried out against the available experimental data in terms of temperature profiles. The effect of free stream air velocity on the fuel mass burning rate and the movement of the flame anchoring point is further investigated. The emphasis is on investigating flame anchoring point, located upstream of the leading edge at low air velocities, and its movement towards and away from the leading edge of the fuel surface, as the air velocity is increased. This is studied by defining and evaluating local or cell based chemical and flow time scales and their ratios.