Development and experimental characterization of metal 3D-printed scalable swirl stabilized mesoscale burner array

The development of a mesoscale burner array capable of sustaining stable, clean, and compact flames suited for a variety of applications with performance and emission characteristics comparable to that of existing large scale burners is presented. The proposed architecture offers significant improvements in flame stability, by minimizing susceptibility to extinction, while maintaining high combustion efficiency and low emission levels under ultra-lean operating conditions for a wide range of combustion power outputs. A prototype 4x4 mesoscale burner array was designed and manufactured using Direct Metal Laser Sintering process (DMLS). The combustor array operates on gaseous fuel (methane) and employs a combination of swirl and bluff body for flame stabilization. The mesoscale burner array can sustain ultra-lean flames with lean blow off limits (LBO) of around ? = 0.65 independent of combustor power output that ensures adequate scalability. Thermocouple measurements indicated minimal element-to-element temperature variations with measured temperatures reaching adiabatic flame temperature levels indicating reduced heat loss due to increased flame interaction. Combustion efficiencies, about 98%, were estimated using Gas Chromatography-Mass Spectrometry (GCMS) analysis of the exhaust gas. The detected levels of combined unburned hydrocarbon (UHC) and carbon monoxide (CO) emissions were well below 0.1% by mass. Thus, the potential for an optimized mesoscale architecture which can be seamlessly scaled over a wide range of combustor power outputs capable of powering large scale gas turbines to compact portable units without any performance deterioration or loss in power to weight ratio has been successfully demonstrated.