MODELING GRAVITY EFFECT ON DIFFUSION FLAMES STABILIZED AROUND A CYLINDRICAL WICK SATURATED WITH LIQUID FUEL

• Published in: Combustion science and technology Vol. 176; no. 12; pp. 2165 - 2191
• Main Authors: ALSAIRAFI, AMMAR, LEE, SHIH-TUEN, T'IEN, JAMES S.
• Format: Journal Article
• Language: English
• Published: London Taylor & Francis Group 01-12-2004; Taylor & Francis
• Subjects: Applied sciences; candle flame; Combustion. Flame; diffusion flame; Energy; Energy. Thermal use of fuels; Exact sciences and technology; gravity effect; Theoretical studies. Data and constants. Metering; candle flame; Combustion; Reaction rate; Modeling; gravity effect; Quenching; Liquid fuel; Numerical analysis; Diffusion flame; Navier Stokes equation; Gas phase; Gravity; Discrete ordinate method
• ISSN: 0010-2202; 0010-2203; 1563-521X
• DOI: 10.1080/00102200490515038

The familiar flames from candles and oil lamps are representative examples of wick-stabilized diffusion flames. The shape and burning characteristics of these flames depend strongly on gravity-induced buoyant flows. To obtain a better understanding of the gravity effect, a diffusion flame model has been formulated and numerically solved. In the computation, gravity is treated as a parameter, spanning from zero to the high blowoff limit. The model includes realistic wick and candle geometry but assumes that the wick surface is coated with liquid fuel. The gas-phase formulation consists of the full Navier-Stokes equations with a one-step finite-rate overall chemical reaction. Gas-phase flame radiation, important in low gravity near the quenching limit, is included by solving the axisymmetric radiation transfer equation using the S
N
discrete ordinates method. The computed results include flame and flow structures, heat flux distributions, the energy budget, and the overall burning characteristics as a function of gravity and wick diameter.