Enhancing Thermal and Exergy Performances in a CO2-Free Micro-combustor with Reverse Flow Double-channel Outlet Structure

The present study proposes a reverse flow single-channel inlet and double-channel outlet (SIDO) micro-combustor for the analysis of the thermal performance and nitrogen oxide emission characteristics of ammonia/hydrogen-fuelled energy conversion system. Comparison is then made between the proposed system and the conventional single-inlet and single-outlet system. The findings indicate that the SIDO combustor enhanced thermal performances. Increasing the inlet pressure Pin improves thermal performance and exergy efficiency while reducing nitrogen oxide emissions. Increasing the inlet flow velocity Vin can enhance the temperature uniformity of the combustor wall. It is also found that the ammonia combustion convection heat transfer performance is optimized, when Vin = 1.25 m/s. Increasing the equivalence ratio Φ leads to a reduction of nitrogen oxide emissions, and the micro-combustor has better overall performance, when Φ = 1.0. Finally, Increasing the blending ration of hydrogen with ammonia Φb give rise to a decayed advection but enhanced diffusion, and the pressure loss (Ploss) can be reduced. This present study confirms the viability of employing the SIDO reverse flow structure to enhance thermodynamic performances from micro-combustion energy conversion systems.