Analysis of Criterion Number of Heat Transfer in Micro Catalytic Combustion Process

Abstract

Based on a detailed chemical reaction mechanism including gas phase reaction and surface catalytic reaction, adopting the CFD software to simulate the combustion process of premixed hydrogen-oxygen in a sub-millimeter burner, and introducing a calculating model of criterion number of heat transfer, a comparative analysis of surface catalytic conditions is performed to find out the heat transfer characteristics during combustion process. The simulation results show that the effects of inlet velocity on Nux number vary regionally when gas phase reaction combined with surface catalytic reaction. As inlet velocity increases, Nux number firstly increases and then decreases in low velocity. While in high inlet velocity, the Nux number of entrance region is in the negative half shaft that means the direction of heat transfer has changed. Inlet temperature has comparatively less effects on Nux number in micro catalytic combustion process under the computational conditions. When the temperature is fixed, the Nux number with catalytic is higher than those without catalytic and the difference is more obvious in lower temperature. Key words:Micro combustion, Catalytic combustion, Criterion number of heat transfer, Dimensionless analysis