A Novel Micro-Thermophotovoltaic Combustor of Hydrogen-Air to Enable Ultra-Lean Combustion, High Thermal Output and NO Low Emissions

This study presents a novel micro-combustor (MC) design called micro-trapped vortex combustor (MTVC) for micro-thermophotovoltaic (MTPV) devices used in small-scale electricity generation. Traditional MC designs struggle to operate efficiently under ultra-lean regimes due to flame quenching, limiting their performance. The proposed MTVC incorporates the trapped vortex concept, inspired by aeronautical applications, to improve thermal performance and stability under ultra-lean conditions. Numerical simulations, using the Navier-Stokes and energy equations for laminar and reactive flow, are conducted to compare the MTVC with conventional micro-backward-step combustors (MBSCs) under hydrogen (H2)-air mixture combustion. The study focuses on key performance parameters such as temperature distribution, heat recirculation, flame shape, flow topology, radiative power and emissions. The results show that the MTVC can operate at an ultra-lean equivalence ratio of Phi = 0.5, while the MBSC experiences flame quenching below Phi = 0.7. The MTVC design achieves up to 26.51% higher radiative power and a 36% improvement in energy conversion efficiency compared to traditional combustor designs. Additionally, the MTVC produces 43% less nitrogen oxides (NOx) emissions, demonstrating its potential for both higher efficiency and reduced environmental impact in portable power applications.