Combustion Characteristics on Colorless Distributed Combustion (CDC) in a Cyclonic Burner

Abstract

Colorless distributed combustion (CDC) is a novel combustion method. Ultra-low NOx and CO pollutant emissions, more uniform thermal field, stable flame formation, equally temperature distribution, etc. can be provided by CDC conditions. CDC can be performed to different type of burners likewise cyclonic burner. Cyclonic burners could provide more residence time on account of intensely internal circulation compared to conventional designated burners. On the other hand CDC is attained by external recirculation. Therefore, non-premixed combustion of methane using a cyclonic burner was modelled through a commercial computational fluid dynamics (CFD) code to enable both external and internal recirculation in the study presented. In the modelings, Reynolds Stress Model that predicts accurately higher level turbulence closures was used as the turbulence model. The assumed-shape with β-function Probability Density Function non-premixed combustion and P-1 radiation models were also used as the combustion and radiation models, respectively. In order to achieve transition to CDC, CO2 as the diluent was selected to decrease oxygen concentration in the oxidizer from 21% to 17%. The transition to CDC was reached at nearly an oxygen concentration of 17% by burning methane at an equivalence ratio of 0.83 with reducing oxygen concentration in the oxidizer by CO2. Ultra-low NOX is achieved for favorable conditions. Besides, CO levels was reduced substantially.

Keywords

• Colorless Distributed Combustion,Methane,Cyclonic Burner,CFD,Carbon Dioxide

References

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