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Modelling and validation of the formation and oxidation of cenospheres in a confined spray flame
Author(s) -
Yuan J.,
Semião V.,
Carvalho M. G.
Publication year - 1997
Publication title -
international journal of energy research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.808
H-Index - 95
eISSN - 1099-114X
pISSN - 0363-907X
DOI - 10.1002/(sici)1099-114x(199711)21:14<1331::aid-er351>3.0.co;2-2
Subject(s) - combustion , cenosphere , soot , turbulence , mechanics , diffusion flame , combustor , turbulent diffusion , heat transfer , work (physics) , chemistry , materials science , thermodynamics , physics , composite material , fly ash , organic chemistry
Oil combustion generated particulates are mainly soot formed during gas‐phase reactions and cenospheres, consisting of ash and unburnt carbon, formed by the liquid‐phase pyrolysis. Both kinds of particulates may lead to fouling, augment emissions and change the heat transfer process inside industrial furnaces. In this work, a model to predict the formation, oxidation and spatial distribution of cenospheres is presented and it is developed based on experimental results and on the governing physical mechanisms. This model was coupled to the standard dual eulerian–lagrangian framework to predict two‐phase flows combustion. The gas‐phase combustion‐related properties are calculated by means of time‐averaged eulerian conservation equations, in addition to the k –ε turbulence model. The droplets and cenospheres balance equations are solved in a lagrangian fashion, with a stochastic approach to turbulent dispersion. The gaseous turbulent‐diffusion flame is modelled using a clipped‐Gaussian pdf to account for fluctuations of scalar properties. Chemistry is assumed to be fast. Radiation is modelled by the discrete transfer method. In order to validate the model, the whole procedure was applied to the prediction of a cylindrical laboratory furnace, oil‐fired by an industrial‐type burner, where experimental data are available. The comparison of predictions against experimental values showed good agreement and, therefore, the validity of the model. The study has proved that the reduction of particulate emissions is achievable through control of aerodynamics, combustion and the quality of atomization. © 1997 by John Wiley & Sons, Ltd.