Numerical modeling of hydrogen catalytic reactions over a circular bluff body

• Published in: International journal of hydrogen energy 2022-10, Vol.47 (88), p.37204-37217
• Main Author: Wu, Chih-Yung
• Format: Article
• Language: English
• Subjects: Catalytic combustion; Conversion efficiency; Exergy; Rod-type catalytic reactor; von Kármán vortex shedding
• ISSN: 0360-3199; 1879-3487
• DOI: 10.1016/j.ijhydene.2021.12.006

This paper was intended to delineate numerical research for hydrogen catalytic combustion over a circular cylinder. The wire/rod-type catalytic reactor is a simple geometry reactor with an economical design with less pressure loss. For the single rod in the reaction channel, the flow characteristic and the difference of conversion efficiency between non-gas-phase reaction and gas-phase reaction have been delineated in the present study. The flow field and the chemical reactions were numerically modeled using 2D Large Eddy Simulation combined with the gas-phase and surface reaction mechanisms. The results show that the current numerical simulation has been validated to precisely predict the vortex shedding and its frequency in the cold flows. Despite the variation trends being dominated by the upstream flow, the vortex shedding phenomena were affected by the flue gas generated from the rod surface. It can be seen from the linear relationship between the vortex shedding frequency of reacting flow and Reynolds Number. It is noted that the vortex shedding vanished if the gas-phase reaction was ignited in the reaction channel. In addition, the geometric modified conversion efficiency was proposed to delineate an indicator that could be potential for the optimization of rod-type catalytic reactor. In summary, the fundamental study of a rod in a 2D flow channel can provide information for optimizing the catalytic design or the rod array arrangement in the reactor. Moreover, the rod can also be a partial catalytic flame holder to ignite and stabilize the gas-phase reaction. The obtained results could be the potential for practical applications of rod-type catalytic combustion, catalytic gas turbine, hydrogen generation, partially catalytic reaction flame holder, and other catalytic reactions that can be appreciated. •2D LES was utilized to evaluate catalytic rod/bluff body in the reacting flow.•von Kármán vortex shedding and its frequency can be precisely modeled.•Geometric modified conversion efficiency was proposed to a performance indicator.•Obtained results can be the basis for the design of catalytic reactor or flame holder.