Effect of wall thermal conductivity on the heterogeneous combustion of hydrogen-air mixtures over platinum in catalytic micro-combustor

Research Article

Effect of wall thermal conductivity on the heterogeneous combustion of hydrogen-air mixtures over platinum in catalytic micro-combustor

Junjie Chen, Wenya Song

Corresponding Author : Junjie Chen,

School of Mechanical and Power Engineering, Henan Polytechnic University, Jiaozuo, Henan, China.

Email ID : concjj@escience.cn

Received : 2015-11-27 Accepted : 2016-01-02 Published : 2016-01-02

Abstract : The hetero-/homogeneous combustion of hydrogen-air mixtures over platinum in catalytic micro-combustors were investigated numerically and experimentally. Experiments were performed in a catalytic channel-flow micro-reactor. Catalysts consisting of platinum supported on alumina powder were prepared and tested. Numerical simulations were carried out with a two-dimensional computational fluid dynamics model in conjunction with detailed heterogeneous and homogeneous reaction mechanisms. Specific objectives are to study the effects of combustor wall conductivity on heterogeneous combustion characteristics and the steady-state, self-sustained flame stability of hydrogen-air mixtures. Hydrogen-air heterogeneous flame is found that it can be stabilized in narrow channels but very careful design is necessary. Large axial and transverse gradients are observed even at these small scales under certain conditions. Wall thermal conductivity is vital in determining the flame stability of the system, as the walls are responsible for the majority of the upstream heat transfer as well as the external heat losses. Hydrogen heterogeneous flames are more robust than methane heterogeneous flames. The catalytic self-ignition nature of hydrogen-air mixtures offers an opportunity to catalytic self-ignite hydrocarbons, resulting in a way toward elimination of ignition sources from micro-scale devices. Design recommendations are made, engineering maps denoting flame stability are constructed, and comparisons with methane-air systems are made.

Keywords : Micro-combustion; Heterogeneous combustion; Flame stability; Micro-combustion; Supported platinum catalysts; Wall thermal conductivity; Computational fluid dynamics

Citation : Junjie Chen et al(2016). Effect of wall thermal conductivity on the heterogeneous combustion of hydrogen-air mixtures over platinum in catalytic micro-combustors. J. of Advancement in Engineering and Technology V4I1. DOI : 10.5281/zenodo.890924

Copyright : © 2016 Junjie Chen. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

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