Theoretical and Numerical Analysis of Fuel Droplet Combustion Parameters via Different Combustion Models
Engineering and Technology Journal,
2008, Volume 26, Issue 10, Pages 1282-1300
AbstractThe study introduces a theoretical analysis and numerical solution for the combustion
of two kinds of hydrocarbon fuel droplet inside the combustion chamber. The study employs
three mathematical models to analyze the combustion process, conventional (classical) model,
transient model, and moving droplet model. The combustion process of a stagnant droplet in
the steady state was analyzed in the classical model, while, in the transient model, it was
assumed that there is a period of time in the stages of the droplet combustion in which the
droplet is heated before combustion, For the moving droplet model, the film boundary
approximation was incorporated to express the effects of the relative motion on the combustion
process parameters. The effect of change in temperature on the thermo-physical properties of
the fuel was adopted through the three models. For the classical and moving droplet models, a
convenient approximation was adopted for the heat transferred inside the droplet.
Computer programs were created to evaluate the required properties, solving the
ordinary differential equations evaluated from heat and mass transfer balances, and then
construct systems of non-linear equations.
The three models show that thermo physical properties are strong functions to
reference temperature. The transient model shows that the period of droplet heat up is most
effective. For the moving droplet combustion model it was shown that the relative movement
between droplet and ambient surrounding gas enhanced the mass burning rate and reduced the
droplet lifetime. The film theory approach was adopted in moving droplet model.
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