Geometrical optimization of premixed hydrogen-air combustion in a novel counter-flow preheating micro-combustor

Developing a more efficient and cleaner combustion technologies is a major step in realizing the sustainable Development Goals. By using Computational Fluid Dynamics and Response Surface Methodology, this study, optimizes a novel counter-opposed combustor with platinum-coated, stepped baffles to enhance the combustion efficiency. Key geometrical parameters such as baffle lengths (L1 and L2), gaps (L3) and height (H) are studied. The study found that, the optimization objectives of reducing H2 outlet mass fraction, increasing outlet H2O mass fraction and outlet temperature were usefully achieved. Due to the flow's laminar and high velocity nature, the high temperature flow could not effectively reach the preheat zones of the upstream baffle, however, hydrogen was completed burned. The optimization identified three geometric configurations, with one candidate point (P1 = 5.497 mm, P2 = 0.616 mm, P3 = 1.668 mm, and P4 = 0.182 mm) achieving the best performance in terms of outlet temperature and H2O mass fraction. These insights can be leveraged to guide the design and operation of the system, ensuring that it performs at its best, while minimizing the presence of H2 at the outlet, and achieve a suitable outlet temperature, all of which contribute to the overall efficiency and effectiveness of the process.