Combustion characteristics of a small-scale combustor with a percolated platinum emitter tube for thermophotovoltaics

A small-scale combustor is one of the most important components in developing the small-scale thermophotovoltaic (TPV) power systems. In order to enhance the flame stabilization and to have a bright incandescent emitter, a platinum tube is used to serve as an emitter. However, a bright incandescent emitter is limited by the operating range of flow velocity and fuel concentration. In the present study, a novel combustion chamber design is proposed to overcome the critical heat loss and flame instability by using a percolated platinum tube as catalyst, emitter, and flame stabilizer. Besides, approaches of delivering fuel/air mixture inside and outside of the catalyst tube can meliorate the heat loss from the chamber wall. Experimental methodology is performed to verify the performance of the proposed percolated-platinum combustor as compared to a plain platinum combustor. In the plain platinum tube the flame only can be stabilized on the backward-facing step inside the tube, but in the percolated platinum tube the flame can be stabilized on the percolated hole inner and outer the tube. It appears that the catalytically induced combustion could be anchored on the percolated-platinum combustor in various conditions of fuel/air distribution and inlet flow velocity, and in the meantime could heat up the chamber wall to incandescent condition. Concept, design, and demonstration of the combustor are addressed and discussed in the paper.