Abstract
In contrast to constant-pressure combustion systems, isochoric combustion systems, such as internal combustion engines, exhibit a
strong coupling between pressure and the combustion process. During isochoric combustion, the heat released by the flame leads to
a pressure increase, which in turn elevates the temperature of both unburned and burned gases. As a result, combustion takes place
under time-varying thermodynamic conditions. This study investigates how these evolving thermodynamic conditions influence
flame-wall interactions in turbulent flames using Direct Numerical Simulations (DNS) of spherical expanding flames within a cubic
domain enclosed by inert, isothermal walls. The flow field is initialized with homogeneous isotropic turbulence (HIT). The study
investigates three different fuels that are of important interest in research: (i) a premixed hydrogen/air flame at fuel-lean conditions,
(ii) a methane/air flame, and (iii) a pre-cracked ammonia/air flame. The operating conditions for each flame are selected to ensure
a similar laminar burning velocity. Key quenching characteristics are analyzed, including the wall heat flux and the quenching
distance. The results show that a rise in reactant pressure leads to a time-dependent increase in wall heat flux. Furthermore, the
study compares different fuels, with a focus on the influence of thermodiffusive instabilities (TDI), showing that TDI significantly
elevates wall-heat fluxes and all three fuel-mixtures exhibit different quenching characteristics.