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^*, Xuhui Gao, Deguang Xu

Frontiers in Heat and Mass Transfer, Vol.6, pp. 1-13, 2015, DOI:10.5098/hmt.6.10

Abstract Effect of wall thermal conductivity on hydrogen self-ignition and hydrogen-assisted ignition of propane-air mixtures in different feeding modes from ambient cold-start conditions were investigated numerically with chemical kinetic model in Pt/γ-Al2O3 catalytic micro-combustors. For the steady and transient state, effect of wall thermal conductivity on self-ignition characteristics of lean hydrogen-air mixtures was presented, and hydrogenassisted combustion of propane-air mixtures was investigated numerically in the co-feed mode and the sequential feed mode. The computational results indicate the large thermal inertia of the micro-combustor solid structure leads to slow temperature dynamics, and transient response is dominated by… More >