Junjie Chen^* , Baofang Liu, Longfei Yan, Deguang Xu

Frontiers in Heat and Mass Transfer, Vol.11, pp. 1-15, 2018, DOI:10.5098/hmt.11.2

Abstract The combustion and emissions characteristics of methane-air mixtures in high-temperature catalytic micro-combustors were studied numerically. Both the heterogeneous and homogeneous chemistry were modeled simultaneously using detailed reaction mechanisms in order to better understand the role of each pathway in determining the product distributions. Computational fluid dynamics simulations were performed at a variety of pressures, temperatures, compositions, and combustor dimensions to determine their effects on the combustion and emissions characteristics. Comparisons were made between the results obtained for a purely heterogeneous case, a purely homogeneous case, and a coupled homogeneousheterogeneous case. It was shown that homogeneous More >

Junjie Chen^* , Wenya Song, Deguang Xu

Frontiers in Heat and Mass Transfer, Vol.8, pp. 1-10, 2017, DOI:10.5098/hmt.8.21

Abstract The combustion and heat transfer characteristics of hydrogen-air or methane-air mixtures in catalytic micro-combustors were studied numerically to assess the impact of wall thermal properties and key operation parameters on the thermal uniformity. A two-dimensional computational fluid dynamics (CFD) model was developed with detailed hetero-/homogeneous chemistry, heat conduction within the solid wall, surface radiation heat transfer, and external heat losses. Parametric studies were carried out to investigate the effect of wall thermal conductivity, feed composition, and flow rate on the thermal uniformity during highly exothermic catalytic reactions. Comparisons of hydrogen- with methane-air systems were made.… More >

Junjie Chen^*, Wenya Song, Xuhui Gao, Longfei Yan, Deguang Xu

Frontiers in Heat and Mass Transfer, Vol.7, pp. 1-9, 2016, DOI:10.5098/hmt.7.3

Abstract The flame stability of single-pass heat-recirculation micro-combustors was investigated using computational fluid dynamics and compared to singlechannel micro-combustors with respect to critical heat loss coefficient and total power loss. The effect of wall thermal conductivity was also explored. The simulations show that heat recirculation profoundly affects blowout because of preheating of the cold incoming gases but has only minimal effect on extinction. In the limit of low-conductivity walls, the heat-recirculation micro-combustor is much more stable than the single-channel microcombustor. Under certain conditions, the heat recirculation micro-combustor can operate with room-temperature inlet and outlet streams and More >

Junjie Chen^*, Longfei Yan, Wenya Song

Frontiers in Heat and Mass Transfer, Vol.5, pp. 1-6, 2014, DOI:10.5098/hmt.5.16

Abstract To understand the effect of different thermal conductivities on catalytic combustion characteristics, effect of thermal conductivity on micro-combustion characteristics of hydrogen-air mixtures in Pt/γ-Al₂O₃ catalytic micro-combustors were investigated numerically with detailed chemical kinetics mechanisms. Three kinds of wall materials (100, 7.5, and 0.5 W/m·K) were selected to investigate the effect of heat conduction on the catalytic combustion. The simulation results indicate that the catalytic reaction restrains the gas phase reaction in Pt/γ-Al₂O₃ catalytic micro-combustors. The gas phase reaction restrained by Pt/γ-Al₂O₃ catalysts is sensitive to thermal boundary condition at the wall. For most conditions, the gas phase More >