Control of radiative heat transfer in high-temperature environments via radiative trapping—Part I: Theoretical analysis applied to pressurized oxy-combustion

•An approach is proposed to control wall heat flux in high temperature reacting flows.•Effects of temperature and absorption coefficient profiles on local heat flux are studied.•In optically dense media much radiation can be trapped with proper temperature gradient.•Radiative trapping can occur in a pressurized system with properly designed burner.•A method is developed to allow for a simple and convenient prediction of wall heat flux.