TY - JOUR
T1 - A statistical analysis of developing knock intensity in a mixture with temperature inhomogeneities
AU - Luong, Minh Bau
AU - Desai, Swapnil
AU - Pérez, Francisco E. Hernández
AU - Sankaran, Ramanan
AU - Johansson, Bengt
AU - Im, Hong G.
N1 - KAUST Repository Item: Exported on 2020-10-01
Acknowledgements: This work was sponsored by King Abdullah University of Science and Technology and used the resources of the KAUST Supercomputing Laboratory.
PY - 2020/7/27
Y1 - 2020/7/27
N2 - Knock formation and its intensity for a stoichiometric ethanol/air mixture under a representative endgas auto-ignition condition in IC engines with temperature inhomogeneities are investigated using multidimensional direct numerical simulations (DNS) with a 40-species skeletal mechanism of ethanol. Two- and three-dimensional simulations are performed by systematically varying temperature fluctuations and its most energetic length scale, lT. The volumetric fraction of the mixture regions that have the propensity to detonation development, FD, is proposed as a metric to predict the amplitude of knock intensity.It isfound that with increasing lT, FD shows a good agreement with the heat release fraction of the mixture regions with pressure greater than equilibrium pressure, FH. The detonation peninsula is well captured by FD and FH when plotting them as a function of the volume-averaged ξ , ξ, (ξ = a/Ssp is the ratio of the acoustic speed, a to the ignition front speed, Ssp). Decreasing lT is found to significantly reduce the super-knock intensity. The results suggest that decreasing lT, as in engines with tumble desig
AB - Knock formation and its intensity for a stoichiometric ethanol/air mixture under a representative endgas auto-ignition condition in IC engines with temperature inhomogeneities are investigated using multidimensional direct numerical simulations (DNS) with a 40-species skeletal mechanism of ethanol. Two- and three-dimensional simulations are performed by systematically varying temperature fluctuations and its most energetic length scale, lT. The volumetric fraction of the mixture regions that have the propensity to detonation development, FD, is proposed as a metric to predict the amplitude of knock intensity.It isfound that with increasing lT, FD shows a good agreement with the heat release fraction of the mixture regions with pressure greater than equilibrium pressure, FH. The detonation peninsula is well captured by FD and FH when plotting them as a function of the volume-averaged ξ , ξ, (ξ = a/Ssp is the ratio of the acoustic speed, a to the ignition front speed, Ssp). Decreasing lT is found to significantly reduce the super-knock intensity. The results suggest that decreasing lT, as in engines with tumble desig
UR - http://hdl.handle.net/10754/664485
UR - https://linkinghub.elsevier.com/retrieve/pii/S1540748920300924
U2 - 10.1016/j.proci.2020.05.044
DO - 10.1016/j.proci.2020.05.044
M3 - Article
SN - 1540-7489
JO - Proceedings of the Combustion Institute
JF - Proceedings of the Combustion Institute
ER -