Visual investigation on optimizing combustion characteristic of porous media burner combined with bluff body

ABSTRACT

Coalbed methane as an unconventional natural gas is suitable for the utilization in thermal photovoltaic systems through optimized burners. In order to improve the radiation and utilization efficiency of coalbed methane, a combination of bluff body and porous media was proposed. Moreover, the bluff body spacing and porous media structure were changed to analyze the influence on flame characteristics. The results showed that the maximum temperature and radiation efficiency increased with decreasing of bluff body spacing. When the bluff body spacing was 30 mm, the maximum temperature of 933 K was obtained, and the radiation efficiency increased by 68%. The increase of the equivalence ratio also improved the radiation efficiency, and the maximum radiation efficiency was 14.5% at φ = 0.90. In addition, the increase of inlet velocity and bluff body spacing was beneficial to downstream flame propagation, but had a negative effect on upstream propagation. At v_in = 40 cm/s, the maximum downstream propagation velocity was 0.267 mm/s. Due to the difference in thermal conductivity, flame fragmentation occurred in the 8 mm pellets, but the flame propagation was gradually stable with the increase of bluff body temperature.

KEYWORDS:

• Porous media
• Bluff body
• Combustion wave propagation
• Radiation efficiency
• Coalbed methane

Acknowledgements

The authors wish to acknowledge the support to this work by the Knowledge Innovation Program of Wuhan-Basic Research, the scholarship from the China Scholarship Council (No. 202006955001), the National Natural Science Foundation of China (No. 51804237), the Natural Science Foundation of Hubei Province of China (No. 2018CFB207), and the Research Funds of Anhui Xinhua University (No. 2022zr005).

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Notes on contributors

Huaming Dai

Huaming Dai is an associate professor in Wuhan University of Technology. His area of interests includes efficient utilization of clean energy and hydrogen production.

Hongchao Dai

Hongchao Dai is a master student in Wuhan University of Technology and focuses on the efficient utilization of clean energy.

Bingqian Zhang

Bingqian Zhang completed her master's degree in Wuhan University of Technology And currently, she is a teacher in Anhui Xinhua University.