Effect of inlet and outlet configurations on blow-off and flashback with premixed combustion for methane and a high hydrogen content fuel in a generic swirl burner

CATEGORY: SWIRL BURNERS
Applied Energy, Volume 116, 1 March 2014, Pages 288–296
Effect of inlet and outlet configurations on blow-off and flashback with premixed combustion for methane and a high hydrogen content fuel in a generic swirl burner
N. Syred, A. Giles, J. Lewis, M. Abdulsada, A. Valera Medina, R. Marsh, P.J. Bowen, A.J. Griffiths
Gas Turbine Research Centre, Cardiff School of Engineering, Queens Buildings, The Parade, Cardiff CF24 3AA, Wales, UK
Abstract
Analyzes new data for three fuels, natural gas, methane and Coke Oven Gas (COG) in two swirl burners. Flashback and blowoff can be correlated with the inlet tangential velocity, rather than the inlet mass flow, over a range of swirl numbers from 0.8 to more than 4. Geometry and fuel type are important. The correlation gives best fit for a particular outlet geometry and with higher hydrogen content fuels. The correlation still holds with methane and natural gas, especially with confinement.
Analysis of the correlation infers that both blowoff and flashback occurrences are governed by the shear layer surrounding the Central Recirculation Zone (CRZ). The CRZ acts to control the width and strength of the shear flow region. Blowoff was found to occur when the CRZ was extensive and well develop and could be modeled by a well stirred reactor system. Two modes of flashback were found, both of which could be characterized by the same correlation of inlet tangential velocity. The first flashback case occurred at lower swirl numbers when the flame attached to the burner rim and flashed back through the outer boundary layer.
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