The effect of hydrogen enrichment on the forced response of CH4/H2/Air laminar flames
| Autor: | Aimee S. Morgans, Jingxuan Li, Zhengli Lim |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
Materials science
Hydrogen FOS: Physical sciences Energy Engineering and Power Technology chemistry.chemical_element 02 engineering and technology 010402 general chemistry Combustion 01 natural sciences Methane chemistry.chemical_compound Natural gas Renewable Energy Sustainability and the Environment business.industry Fluid Dynamics (physics.flu-dyn) Laminar flow Mechanics Physics - Fluid Dynamics 021001 nanoscience & nanotechnology Condensed Matter Physics 0104 chemical sciences Fuel Technology Volume (thermodynamics) chemistry Compressibility 0210 nano-technology business Ambient pressure |
| Zdroj: | International Journal of Hydrogen Energy |
| Popis: | Hydrogen-enrichment of conventional natural gas mixtures is an actively-explored strategy for reducing pollutant emissions from combustion. This study investigates the effect of hydrogen enrichment on the unsteady flame response to perturbations, with a view to understanding the implications for thermoacoustic stability. The Level Set Approach for kinematically tracking the flame front was applied to a laminar conical premixed methane / hydrogen / air flame subjected to 2D incompressible velocity perturbations. For hydrogen enrichment levels ranging from 0% to 80% by volume, the resulting unsteady heat release rate of the flame was used to generate the Flame Describing Functions (FDFs). This was performed across a range of perturbation frequencies and levels at ambient pressure. The mean heat release rate of the flame was fixed at $\overline{\dot{Q}} = 2.69\ \textrm{kW}$ and the equivalence ratio was set to $\varphi=1.08$ for all hydrogen enrichment levels. Hydrogen-enrichment was found to shift the FDF gain drop-off to higher frequencies, which will increase propensity to thermoacoustic instability. It also reduced the effective flame time delay. Sensitivity analyses at $\varphi = 0.8$ revealed that the changes in FDF were driven predominantly by the flame burning speed, and were insensitive to changes in Markstein length. Comment: Accepted for publication in International Journal of Hydrogen Energy |
| Databáze: | OpenAIRE |
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