Numerical evidence on deflagration fronts in a methane/n-dodecane dual-fuel shear layer under engine relevant conditions
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Fuel, Volume 344
AbstractTo date, high resolution spray-assisted dual-fuel (DF) studies have focused on capturing the ignition process while the subsequent post-ignition events have been largely neglected due to modeling requirements and high computational cost. Here, we use a simplified approach for studying ignition front evolution after ignition. Three-dimensional scale-resolved simulations of igniting shear layers (0≤Re≤1500) are studied to better understand reaction fronts in engine-relevant conditions. We carry out quasi-DNS in a DF combustion setup consisting of premixed n-dodecane/methane/air/EGR at 700K as a fuel stream and premixed methane/air as the oxidizer at a pressure of 60 atmospheres and an ambient temperature of 900 K. The flow solution resolution is δ/10, where δ=laminar flame thickness. The present study primarily focuses on the hypothesized flame formation and its characterization. Under these conditions, the simulations indicate two-stage ignition further leading to reaction front initiation and dual-fuel flame establishment. For Re<1500, a reaction front resembling DF deflagration is demonstrated close to the auto-ignition timescales. At Re=1500, mixing effects promote more rapid dilution and the DF deflagration front formation is slightly delayed although still observed. For the first time, at rather short timescales of 0.2−0.4 IDT (ignition delay time) after the ignition, we provide numerical evidence on DF deflagration front emergence in shear-driven DF combustion processes via 3D numerical simulations for 0<Re≤1500.
Funding Information: This study has been funded by the Academy of Finland (grant numbers 318024, 332784, and 297248). We acknowledge CSC, Finnish IT Center for Science for providing the computational resources. Funding Information: This study has been funded by the Academy of Finland (grant numbers 318024 , 332784 , and 297248 ). We acknowledge CSC, Finnish IT Center for Science for providing the computational resources. Publisher Copyright: © 2023 The Author(s)
Deflagration, Dual-fuel, Flame initiation, Methane, n-dodecane
Kannan , J , Karimkashi , S , Gadalla , M , Kaario , O & Vuorinen , V 2023 , ' Numerical evidence on deflagration fronts in a methane/n-dodecane dual-fuel shear layer under engine relevant conditions ' , Fuel , vol. 344 , 128100 . https://doi.org/10.1016/j.fuel.2023.128100