Biogas is a renewable and clean energy source that plays an important role in the current environment of low- carbon transition. If high-content CO

2

in biogas can be separated

transformed

and utilized

it not only realizes high-value utilization of biogas but also promotes carbon reduction in the biogas field. To improve the combustion stability of biogas

an inhomogeneous

partially premixed stratified (IPPS) combustion model was adopted in this study. The thermal flame structure and stability were investigated for a wide range of mixture inhomogeneities

turbulence levels

CO

2

concentrations

air-to-fuel velocity ratios

and combustion energies in a concentric flow slot burner (CFSB). A fine-wire thermocouple is used to resolve the thermal flame structure. The flame size was reduced by increasing the CO

2

concentration and the flames became lighter blue. The flame temperature also decreased with increase in CO

2

concentration. Flame stability was reduced by increasing the CO

2

concentration. However

at a certain level of mixture inhomogene

ity

the concentration of CO

2

in the IPPS mode did not affect the stability. Accordingly

the IPPS mode of combustion should be suitable for the combustion and stabilization of biogas. This should support the design of highly stabilized biogas turbulent flames independent of CO

2

concentration. The data show that the lower stability conditions are partially due to the change in fuel combustion energy

which is characterized by the Wobbe index (WI). In addition

at a certain level of mixture inhomogeneity

the effect of the WI on flame stability becomes dominant.