Numerical study of effect of wall parameters on catalytic combustion characteristics of CH4/air in a heat recirculation micro-combustor. (15th June 2016)

• Record Type: Journal Article
• Authors: Yan, Yunfei; Wang, Haibo; Pan, Wenli; Zhang, Li; Li, Lixian; Yang, Zhongqing; Lin, Changhai
• Is Part Of: Energy conversion and management. Volume 118(2016)
• Page Start: 474
• Page End: 484
• Publication Date: 2016-06-15
• Subjects: Wall parameter -- Heat recirculation -- Catalytic combustion -- Convection heat transfer coefficient; Direct energy conversion -- Periodicals; Energy storage -- Periodicals; Energy transfer -- Periodicals; Énergie -- Conversion directe -- Périodiques; Direct energy conversion; Periodicals; 621.3105
• DOI: 10.1016/j.enconman.2016.04.026
• Languages: English
• ISSNs: 0196-8904

Abstract

Highlights: Combustion in heat recuperation micro-combustors with different materials was studied. Heat concentration is more obvious with thermal conductivity decreasing. Combustor with copper baffles has uniform temperature distribution and best preheating effectiveness. Influence of wall thermal conductivity is negligible on OH(s) coverage. Methane conversion rate firstly increases and then decreases with h increasing. Abstract: Premixed combustion of methane/air mixture in heat recuperation micro-combustors made of different materials (corundum, quartz glass, copper and ferrochrome) was investigated. The effects of wall parameters on the combustion characters of a CH4 /air mixture under Rhodium catalyst as well as the influence of wall materials and convection heat transfer coefficients on the stable combustion limit, temperature field, and free radicals was explored using numerical analysis methodology. The results show that with a decrease of thermal conductivity of wall materials, the temperature of the reaction region increases and hot spots becomes more obvious. The combustor with copper baffles has uniform temperature distribution and best preheating effectiveness, but when inlet velocity is too small, the maximum temperature in the combustor with copper or ferrochrome baffles is well beyond the melting point of the materials. With an increase in thermal conductivity, the preheat zone for premixed gas increases, but the influence of thermal conductivity on OH(s) coverage is negligible. With an increase of the wall convection heat transfer coefficient, the methane conversion rate firstly increases, then decreases reaching a maximum value at h = 8.5 W/m 2 K, however, the average temperature of both the axis and exterior surface of the combustor decrease.