Hydrogen-air premixed combustion in a novel micro disc-burner with an annular step

Cai, Siqi; Yang, Wenquan; Ding, Yan; Zeng, Qinghua; Wan, Jianlong

doi:10.1016/j.fuel.2021.123015

Cited by 12 publications

(3 citation statements)

References 35 publications

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“…This is modeled through mixed thermal conditions, encompassing a heat transfer coefficient of 20 W/m²-K. The specific quartz glass specific heat capacity and thermal conductivity are 750 J/kg-K and 2 W/m-K [21]. A direct comparison between hydrogen and ammonia as fuels was carried out by establishing a mixture velocity of 6 m/s for hydrogen and varying the equivalence ratio from ignition to 1.…”

Section: Boundary Conditions and Computational Domainmentioning

confidence: 99%

Combustion Efficiency of Carbon-neutral Fuel using Micro-Combustor Designed for Aerospace Applications

De Giorgi,

Cinieri,

Marseglia

et al. 2024

J. Phys.: Conf. Ser.

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Recent advancements in the field of micro combustor research are growing for achieving high-performance systems in micro power generation and microelectromechanical devices. To mitigate the hazardous emissions from carbon fuels, as an alternative, zero-carbon-free fuels ammonia, and hydrogen are being explored in micro combustion processes. The distinctive feature of a micro combustor lies in its significantly higher area to volume ratio in comparison with traditional combustion systems, leading to accelerated combustion reaction rates. However, the small size of micro combustors poses a challenge in achieving efficient mixing of highly reactive fuels like hydrogen and ammonia with oxidizers. The unique properties of micro combustors can lead to differences in the combustion behavior of hydrogen and ammonia compared to larger-scale combustion systems. Hence, examining the performance of carbon-free fuels in micro combustors is crucial for the advancement of clean energy combustion systems. A numerical investigation on a Y-shaped micro-combustor was carried out to identify the aspects of non-premixed combustion of ammonia/air and hydrogen/air. The findings reveal that in the case of hydrogen combustion, stable flames were reached, even at low equivalence ratios. Therefore, the distinct combustion properties of hydrogen and ammonia result in varying NOx emissions, with hydrogen generally leading to higher NOx levels due to its higher flame temperature and increased thermal NOx production.

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Section: Boundary Conditions and Computational Domainmentioning

confidence: 99%

Combustion Efficiency of Carbon-neutral Fuel using Micro-Combustor Designed for Aerospace Applications

De Giorgi,

Cinieri,

Marseglia

et al. 2024

J. Phys.: Conf. Ser.

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“…Both channels represent the inlet conditions with constant flow rates and an inlet temperature of 300 K. A pressure-outlet boundary condition of 1 atm is set at the outlet. The wall is modeled as a no-slip wall with heat transfer to the surroundings accounted for by adopting mixed thermal conditions that include a heat transfer coefficient of 20 W/m 2 K. The specific quartz glass specific heat capacity and thermal conductivity are 750 J/kgK and 2 W/mK [57]. A direct comparison between H 2 and NH 3 as fuels was conducted, setting a mixture velocity of 6 m/s for H 2 and different Φ from lean blow-out to 1.…”

Section: Computational Domain and Boundary Conditionsmentioning

confidence: 99%

Toward Zero Carbon Emissions: Investigating the Combustion Performance of Shaped Microcombustors Using H2/Air and NH3/Air Mixtures

Cinieri,

Shah,

Marseglia

et al. 2023

Aerospace

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The research effort in the microcombustor field has recently increased due to the demand for high-performance systems in microelectromechanical and micro power generation devices. To address rising concerns about pollutants from fossil sources, zero-carbon fuels such as hydrogen (H2) and ammonia (NH3) have been considered as an alternative in microcombustion processes. In a microcombustor, the surface area-to-volume ratio is much higher compared to conventional combustion systems, resulting in faster heat transfer rates and more intense combustion reactions. However, achieving efficient mixing of fuel and an oxidizer in a microcombustor can be challenging due to its small size, particularly for highly reactive fuels like H2. For NH3, challenges in microcombustion involve a low reactive, high ignition temperature (923 K vs. 793 K of H2) and high concentration of NOx combustion products. Therefore, studying the performance of these fuels in microcombustors is important for developing clean energy technologies. In this paper, to explore features of non-premixed NH3/air and H2/air combustion in micro-scale combustors, an Ansys Fluent numerical investigation was conducted on a Y-shaped microcombustor. Results show that for combustion with H2, stationary flames can be achieved even at lower equivalence ratios. Additionally, the pollutants generated from H2 in the flame are generally twice those of NH3. The overall efficiency of the microcombustor is two times greater for NH3 conditions than for H2 conditions.

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“…Sankar et al [17] studied the application of different techniques for implementing liquid fuels in different types of micro-combustors for power generation. Cai et al [18] introduced a novel micro-disc burner with an annular step by using H 2 as fuel. It was observed in the study that a smaller Re value and larger Φ are suitable for the combustor; moreover, with the increase in thermal conductivity λ, the uniformity of the outer wall temperature was also increased.…”

Section: Introductionmentioning

confidence: 99%

Impact of H2 Blending of Methane on Micro-Diffusion Combustion in a Planar Micro-Combustor with Splitter

Sudarsanan,

Velamati,

Alquaity

et al. 2024

Energies

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An investigation into the non-premixed combustion characteristics of methane in a planar micro-combustor with a splitter was performed. The impact of blending methane with hydrogen on these characteristics was also analyzed. Additionally, the effects of inlet velocity and global equivalence ratio on flame location, flame temperature, combustion efficiency and outer wall temperature were studied for three different fuel compositions: pure methane (MH0), 60% methane with 40% hydrogen (MH40), and 40% methane with 60% hydrogen (MH60)). A heat recirculation analysis of the combustor wall was conducted to determine the amount of heat recirculated into the unburnt gas at various inlet velocities for all three fuel compositions. The results demonstrated that the stability limit of methane in terms of inlet velocity (1–2 m/s) and global equivalence ratio (1.0–1.2) was significantly enhanced to 1–3 m/s and 0.8–1.2, respectively, with the addition of hydrogen. At an inlet velocity of 2 m/s, the flame location of 3.6 mm for MH0 was significantly improved to 2.2 mm for MH60. Additionally, outer wall temperature exhibited a rise of 100 K for MH60 compared to MH0. Furthermore, from heat recirculation analysis, when the ratio of heat recirculated to heat loss exceeded unity, the flame started exhibiting the lift-off phenomenon for all the fuel compositions.

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Hydrogen-air premixed combustion in a novel micro disc-burner with an annular step

Cited by 12 publications

References 35 publications

Combustion Efficiency of Carbon-neutral Fuel using Micro-Combustor Designed for Aerospace Applications

Combustion Efficiency of Carbon-neutral Fuel using Micro-Combustor Designed for Aerospace Applications

Toward Zero Carbon Emissions: Investigating the Combustion Performance of Shaped Microcombustors Using H2/Air and NH3/Air Mixtures

Impact of H2 Blending of Methane on Micro-Diffusion Combustion in a Planar Micro-Combustor with Splitter

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