A projection procedure to obtain adiabatic flames from non-adiabatic flames using heat flux method

TY - JOUR

T1 - A projection procedure to obtain adiabatic flames from non-adiabatic flames using heat flux method

AU - Han, Xinlu

AU - Wang, Zhihua

AU - He, Yong

AU - Wang, Shixing

AU - Zhu, Yanqun

AU - Liu, Yingzu

AU - Konnov, Alexander A.

PY - 2020

Y1 - 2020

N2 - Laminar burning velocity S L at elevated temperature T u and its temperature dependence coefficient α in SL/S0L = (Tu T0u)α are important parameters for industrial applications. However, experimental systems with high unburned gas temperatures may encounter pre-dissociation, leading to significant data scattering in the measurements. To negate this, the present work proposes a projection procedure to obtain adiabatic flame parameters at various unburned gas temperatures using non-adiabatic flames on a heat flux burner, by which the preheating can be achieved within much shorter time scale than, e.g., in conventional spherical flame methods, and the advantage of good data consistency in the heat flux method is kept. Burning velocity experiments were carried out with CH 4 + air atmospheric flames covering T u = 298-473 K, and the results show good agreement with the proposed projection equations. OH * spontaneous emission profiles were measured, indicating that the projection may extend to other flame characteristics. Uncertainty of the projection process was evaluated and comparisons were made with six popular kinetic mechanisms: GRI-Mech, FFCM-1 mech, Konnov mechanism, Glarborg mechanism, San Diego mechanism and Aramco mechanism. It is found that the simulated coefficients α are higher than experimental data especially at rich conditions; this is also found for literature values of high unburned gas temperature experiments. Possible reasons for this divergence are discussed.

AB - Laminar burning velocity S L at elevated temperature T u and its temperature dependence coefficient α in SL/S0L = (Tu T0u)α are important parameters for industrial applications. However, experimental systems with high unburned gas temperatures may encounter pre-dissociation, leading to significant data scattering in the measurements. To negate this, the present work proposes a projection procedure to obtain adiabatic flame parameters at various unburned gas temperatures using non-adiabatic flames on a heat flux burner, by which the preheating can be achieved within much shorter time scale than, e.g., in conventional spherical flame methods, and the advantage of good data consistency in the heat flux method is kept. Burning velocity experiments were carried out with CH 4 + air atmospheric flames covering T u = 298-473 K, and the results show good agreement with the proposed projection equations. OH * spontaneous emission profiles were measured, indicating that the projection may extend to other flame characteristics. Uncertainty of the projection process was evaluated and comparisons were made with six popular kinetic mechanisms: GRI-Mech, FFCM-1 mech, Konnov mechanism, Glarborg mechanism, San Diego mechanism and Aramco mechanism. It is found that the simulated coefficients α are higher than experimental data especially at rich conditions; this is also found for literature values of high unburned gas temperature experiments. Possible reasons for this divergence are discussed.

KW - Elevated temperature

KW - Heat flux method

KW - Laminar burning velocity

KW - Temperature dependence

UR - http://www.scopus.com/inward/record.url?scp=85089659103&partnerID=8YFLogxK

U2 - 10.1016/j.proci.2020.07.027

DO - 10.1016/j.proci.2020.07.027

M3 - Article

AN - SCOPUS:85089659103

JO - Proceedings of the Combustion Institute

JF - Proceedings of the Combustion Institute

SN - 1540-7489

ER -