Temperature and radiative characteristics of cylindrical porous Ni-Al burners

Premixed gas combustion in cylindrical porous radiant burners with different thickness of the porous layer made by combustion synthesis is considered. Temperature and radiative characteristics of porous burners are studied experimentally. Experimental results demonstrate existence of two different combustion regimes, external and internal regimes of combustion, observed at the same values of gas flow rate and methane-air mixture composition. Depending on initial conditions one of these combustion regimes is established. Dependencies of porous-shell temperature, total radiation power and radiation efficiency on the firing rate and mixture composition are obtained for both internal and external combustion regimes. It is found that the internal combustion mode is characterized by higher temperatures of the outer burner surface, higher thermal radiation power and radiation efficiency, as well as more uniform glow of the porous medium compared to the external combustion mode.