Does swirl number affect the radiative and convective heat transfer from diffusion hydrogen-methane blended flames?
Year: 2025
Type: article
Abstract: Industries are exploring hydrogen fuel switching to achieve net-zero targets. Pure hydrogen combustion eliminates carbon dioxide emissions, but this could adversely affect the heating performance since much of the radiative heat transfer from hydrocarbon flames originates from hot carbon dioxide molecules and soot particles, absent from hydrogen combustion.To investigate the effect of swirl number on a flame’s heat transfer, a generic swirl burner was operated at 25 kW thermal input, with three geometric swirl numbers, a fixed equivalence ratio of 1.0 and methane-hydrogen blends of 0-100% by volume. Hydrogen and methane exhibited different radiative and convective heat transfer properties.Results showed that increasing geometric swirl number produced shorter flames with lower radiative heat transfer. The maximum radiative heat flux of a flame occurred between ~50-70% along the flame’s length. Increasing hydrogen blending resulted in an increased flame temperature. 25-50% hydrogen blending enhanced methane flame’s radiative heat transfer, while further blending reduced it. Local convective heat flux correlated well with local gas temperature, regardless of fuel.The ratio of radiation to convection was greatest early in the flame, with convection increasing along the flame’s length. Both heat transfer modes decreased at similar rates with radial distance from the burner centreline.Heat transfer to a steel product was measured via a thermocouple array, representing the total heat transfer in an industrial process, including radiative and convective heat transfer. Combining heat flux, flame temperature and steel product temperature analysis provided a robust methodology for measuring heat transfer across the conditions tested.
Authors: Ben White, Burak Goktepe, Richard Marsh, Steve Morris, Andrew Price
Institution: Cardiff University
Language: English
Subfield: Computational Mechanics
Field: Engineering
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $3,000
OpenAlex ID: W4409237202