Abstract Effect of content of hydrogen (H2) in fuel stream, mole fraction of H2 ( X H 2 ) in fuel composition, and velocity of fuel and co-flow air (… Click to show full abstract
Abstract Effect of content of hydrogen (H2) in fuel stream, mole fraction of H2 ( X H 2 ) in fuel composition, and velocity of fuel and co-flow air ( V a v g ) on the flame characteristics of a co-flow H2/N2 laminar diffusion flame is investigated in this paper. Co-flow burner of Toro et al. [1] is used as a model geometry in which the governing conservation transport equations for mass, momentum, energy, and species are numerically solved in a segregated manner with finite rate chemistry. GRI3 reaction mechanisms are selected along with the weight sum of grey gas radiation (WSGG) and Warnatz thermo-diffusion models. Reliability of the newly generated CFD (computational fluid dynamics) model is initially examined and validated with the experimental results of Toro et al. [1]. Then, the method of investigation is focused on a total of 12 flames with X H 2 varying between 0.25 and 1, and V a v g between 0.25 and 1 ms−1. Increase of flame size, flame temperature, chemistry heat release, and NOx emission formation resulted are affected by the escalation of either X H 2 or V a v g . Significant effect on the flame temperature and NOx emission are obtained from a higher X H 2 in fuel whereas the flame size and heat release are the result of increasing V a v g . Along with this finding, the role of N2 and its higher content reducing the flame temperature and NOx emission are presented.
               
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