Numerical Simulations on Combustion and Heat Transfer in Porous Medium with Different Gyroid Triply Periodic Minimal Surfaces Structures

To investigate the influence of the porous medium with Triply Periodic Minimal Surfaces (TPMS) structures on lower concentration methane combustion. This study analyzed the flow field and heat transfer in the porous medium with three types, i.e. an axial gradual period type, a conical type and a uniform type, through the pore-scale simulation (PSS) approach. In cases of this study, the flashback equivalence ratio of the conical PMB is about 12.5% lower than that of the gradient PMB at the same inlet flow velocity, and the blow-off inlet flow velocity of the conical PMB is about 30% higher than that of the gradient PMB at the same equivalence ratio. Moreover, the flame shape is closely related to the local solid structure and flow velocity. The solid surfaces radiation heat transfer occurred mainly in regions with high solid temperature gradients. Additionally, the absolute value of the radiant heat flux is about 1/4 to 1/5 of the total heat flux, which reflects the proportion of thermal convection in the heat transfer on the solid surface. Convective heat transfer between solid and fluid occurred mainly in the areas of heat recuperation known as preheat zone, and higher inlet flow rates significantly increase the upstream convective heat transfer intensity.