A Porous Media Reciprocal Flow Burner With Embedded Heat Exchangers

Superadiabatic combustion in porous media allows a stable burning of ultra-lean methane/air mixtures, far below flammability limits. The heat regeneration effect of the porous matrix and the low degree of thermal non-equilibrium between the gas and the solid phases keep temperature values above the minimum necessary for combustion and hence the CO and NO_x production at extremely low levels. Due to the transient nature of this phenomenon, a method to confine the combustion into a practical burner has been engineered. The Reciprocal Flow Burner (RFB) is an effective and simple system to achieve this result. A heat exchanger embedded into the pellets makes it an appealing alternative for high-efficiency low-emission heat production. In the present work, a numerical model is compared to experiments to provide a better understanding of heat extraction from a RFB.