TY - JOUR
T1 - Fuel and equivalence ratio effects on transfer functions of premixed swirl flames
AU - Di Sabatino, Francesco
AU - Guiberti, Thibault
AU - Moeck, Jonas P.
AU - Roberts, William L.
AU - Lacoste, Deanna
N1 - KAUST Repository Item: Exported on 2020-10-01
Acknowledgements: This work was funded by the King Abdullah University of Science and Technology, the Deutsche Forschungsgemeinschaft, and the Agence Nationale de la Recherche, through the Green Electric Control of COmbustion (GECCO) project.
PY - 2019/12/18
Y1 - 2019/12/18
N2 - This paper reports on the effects of fuel and equivalence ratio on the response of lean premixed swirl flames to acoustic perturbations of the flow, at atmospheric pressure. The response is analyzed using flame transfer functions, which relate the relative heat release rate fluctuations from the flame to the relative velocity fluctuations of the incoming flow. Two fuels, propane and methane, and five equivalence ratios are considered. The 10 flames investigated are selected to exhibit the local maximum of the transfer function gain around the same frequency, 176 Hz. The results show that changing fuel and equivalence ratio influences both the gain and the phase of the transfer function. The changes observed at 176 Hz, where the dynamics of the flame is mainly controlled by the flame vortex roll-up mechanism, are discussed. Based on the analysis of the flowfields and the flame wrinkling, the laminar burning velocity and the flame temperature are identified as the main parameters controlling the gain. They have two competing effects: first, by enhancing the flame vortex roll-up and, second, by affecting the strength of the vortex generated by the acoustic forcing due to changes in the height of the flame stabilization location.
AB - This paper reports on the effects of fuel and equivalence ratio on the response of lean premixed swirl flames to acoustic perturbations of the flow, at atmospheric pressure. The response is analyzed using flame transfer functions, which relate the relative heat release rate fluctuations from the flame to the relative velocity fluctuations of the incoming flow. Two fuels, propane and methane, and five equivalence ratios are considered. The 10 flames investigated are selected to exhibit the local maximum of the transfer function gain around the same frequency, 176 Hz. The results show that changing fuel and equivalence ratio influences both the gain and the phase of the transfer function. The changes observed at 176 Hz, where the dynamics of the flame is mainly controlled by the flame vortex roll-up mechanism, are discussed. Based on the analysis of the flowfields and the flame wrinkling, the laminar burning velocity and the flame temperature are identified as the main parameters controlling the gain. They have two competing effects: first, by enhancing the flame vortex roll-up and, second, by affecting the strength of the vortex generated by the acoustic forcing due to changes in the height of the flame stabilization location.
UR - http://hdl.handle.net/10754/660223
UR - https://arc.aiaa.org/doi/10.2514/1.B37537
UR - http://www.scopus.com/inward/record.url?scp=85080123424&partnerID=8YFLogxK
U2 - 10.2514/1.B37537
DO - 10.2514/1.B37537
M3 - Article
SN - 1533-3876
VL - 36
SP - 271
EP - 284
JO - Journal of Propulsion and Power
JF - Journal of Propulsion and Power
IS - 2
ER -