Hydrogen-air premixed combustion in a novel micro disc-burner with an annular step

Abstract

A novel micro disc-burner with an annular step using the hydrogen/air premixed mixture is developed in this work, which can act as a heater or heat source with a high stability for the miniature power generators. The combustion and thermal performance of this combustor is studied by the means of numerical simulation. The results show that the excess enthalpy combustion appears at a small equivalence ratio. The thermal output power of the combustor increases with the increased Reynolds number. It is interesting to find that the upper and lower limits of thermal output power and its ratio in the total heat release amount change approximately linearly with the Reynolds number. It is found that the thermal output power and its ratio in the total heat release amount under any conditions are smaller than 102.8 W and 31.41%, respectively. The effects of the thermal conductivity and surface emissivity of solid wall on the combustion characteristics are studied. Both thermal output power and its ratio in the total heat release amount decrease with the increased thermal conductivity. Additionally, the thermal output power remarkably decreases with the decreased surface emissivity. The current work not only provides the guideline for applying this combustor but also helps us to gain insight into the heat transfer characteristic in the radial micro-channel.