Thermal performance improvement of premixed hydrogen/air fueled cylindrical micro-combustor using a preheater-conductor plate

A micro-combustor is the key component of the micro thermo photovoltaic power generation system. The energy conversion efficiency of the system strongly depends on the outer wall temperature and the exergy efficiency of the micro-combustor. A novel preheater-conductor plate was designed to be inserted into a cylindrical micro-combustor to improve the outer wall temperature and the exergy efficiency by preheating premixed hydrogen/air mixture via the preheater plate and conducting out the heat in the combustion chamber via the conductor plate. The impact of the width of preheater plate, the gradually increased and decreased thickness with divergent angle and convergent angle of conductor plate, and the inserted number of conductor plate on the thermal performance of the micro-combustor were investigated. It is found that the gradually varying thickness of the conductor plate has a slight influence on micro-combustor performance compared to other factors. Inserting a preheater-conductor plate with the 0.5 mm-wide preheater plate and the three 0.5 mm-thick conductor plates improve the mean outer wall temperature and the exergy efficiency of the micro-combustor by 173 K and 22.9% respectively. It is indicated that the proposed preheater-conductor plate is capable of considerably improving the thermal performance of premixed hydrogen/air fueled cylindrical micro-combustor. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.