Experimental investigation on combustion characteristics of premixed propane/air in a micro-planar heat recirculation combustor

With respect to micro-thermophotovoltaic (MTPV) system, achieving a higher wall temperature and wider range of flame stability in micro-combustor is pivotal, which may be the most effective method to improve the work efficiency of the device. On this basis, an improved combustor with heat recirculation is designed and fabricated. Experimental investigation has been conducted to study the effects of equivalence ratio and volume flow rate on combustion characteristics of premixed propane/air. Results show that the radiation efficiencies of external wall in heat recirculation combustor are significantly higher than the corresponding value in straight-channel combustor under the same conditions. In the meanwhile, the maximum blowout limit in heat recirculation combustor can be more than three times as that of straight-channel combustor. Furthermore, the baffle length is a critical parameter of the micro-combustor, which can determine the residence time and reaction zone of the propane/air mixture. Accordingly, studies under different baffle length cases have been adopted to further explore the most suitable length in heat recirculation combustor. By contrast, the 15 mm baffle length is the most advantageous, in which case the radiation efficiency of the external wall is highest.