Numerical analysis of laminar diffusion flames—Effects of preferential diffusion of heat and species

✍ Scribed by Toshimi Takagi; Zhe Xu

• Publisher: Elsevier Science
• Year: 1994
• Tongue: English
• Weight: 641 KB
• Volume: 96
• Category: Article
• ISSN: 0010-2180
• DOI: 10.1016/0010-2180(94)90157-0

✦ Synopsis

Numerical computations were made of axisymmetric laminar jet diffusion flames, taking into account detailed chemical kinetics and multicomponent diffusion. The computations are in good agreement with the experimental results of temperature and species concentration in hydrogen/methane/nitrogen fuel flames with coflowing air obtained by Ishizuka and Sakai. It was shown that preferential diffusion of heat and species causes significant amount of excess and deficit of enthalpy, and also an increase and decrease of H 2 mole fraction in the flame. These effects result in higher flame temperature than the maximum adiabatic temperature for the original fuel in the upstream region, and significantly lower temperature near the flame tip. The temperature decrease induced by the decrease of H 2 mole fraction and decrease of excess enthalpy near the flame tip resulting from preferential diffusion is presumed to be the rational explanation for the flame tip extinction (flame tip-opening).