A numerical study on non-premixed H2/air flame stability in a micro-combustor with a slotted bluff-body

Li, Linhong; Fan, Aiwu

doi:10.1016/j.ijhydene.2020.10.024

Cited by 38 publications

(3 citation statements)

References 47 publications

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“…Xiang et al [25] experimentally investigated the effects of total flow rate and fuel/air ratio on the propagation behaviors of diffusion flames, and noise emission was observed in flame propagation in the upstream direction under comparatively higher mixture velocities. Li et al [26] numerically studied the flame stability of a non-premixed H 2 -air mixture in a micro-combustor with a slotted bluff body and found that for a medium blockage ratio of 0.55, the flame blow-off limit appeared to be the highest (34 m/s). It was also found that as the blockage ratio increased, a stretching effect occurred, which ultimately resulted in local extinction and flame splitting.…”

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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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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“…Under the same blockage ratio, the conical bluff body has the best stability characteristic while the horizontal cylinder bluff body is the worst. Li et al 17 numerically studied the effect of bluff body height on the H 2 /air non-premixed flame blowoff limit of a micro-burner. The results show that with the increase of the bluff body height, the flame blowoff limit first increases and then decreases, when the height of the bluff body is 0.3 mm, the blowoff limit is the largest.…”

Section: Introductionmentioning

confidence: 99%

Numerical investigation on combustion flow characteristics of a micro gas turbine swirl combustor with different protruded bluff body structures

Liu

Zeng

Guo

2023

Proceedings of the Institution of Mechanical Engineers, Part A:

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A micro gas turbine swirl combustor with protruded bluff body is proposed. Compared with no bluff body, the protruded bluff body can significantly improve the combustion performance. When the bluff body height is 40 mm and the length is 30 mm, the average outlet NO emission is reduced by 14.43%, the pressure loss is decreased by 5.96%, and the outlet temperature distribution factor (OTDF) is dropped by 31.93%. The influence of different bluff body lengths (15–30 mm) and heights (10–50 mm) on the combustion flow are numerically analyzed further. The results show that the change of bluff body structure will affect the performance of combustor. In the range of 15–25 mm, with the increase of the bluff body length, the scope of central recirculation zone becomes narrower, velocity near the inlet and pressure loss decrease, the OTDF and field synergy angle β both become larger. When the bluff body length grows from 15 mm to 30 mm, the average outlet NO emission increases by 36.74%. The range of the central recirculation zone is gradually widen, and the average reaction rate grows up with the increase of bluff body height. The synergistic effect becomes better, and the heat transfer capacity is enhanced. When the bluff body height grows from 30 mm to 50 mm, the average outlet NO emission reduces from 35.84 ppm to 25.65 ppm.

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“…Yang [27] adopted a cavity design to broaden the blowing limit of the flame, and found that the cavity can improve the combustion efficiency and improve the flame tip splitting phenomenon. He [28] and other relevant scholars have conducted a large number of studies to prove the steady burning effect of blunt body, especially in improving combustion efficiency, making the application of cavity and blunt body in micro combustors reach a high level [29][30][31][32][33][34]. Now, more and more scholars from the perspective of thermal management, are adopting measures to reduce heat loss, so as to pursue efficient and stable combustion.…”

Section: Introductionmentioning

confidence: 99%

Influence of Porous Media Aperture Arrangement on CH4/Air Combustion Characteristics in Micro Combustor

Wang

Feng

et al. 2021

Processes

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Micro-electro-mechanical systems (MEMS) occupy an important position in the national economy and military fields, and have attracted great attention from a large number of scholars. As an important part of the micro-electromechanical system, the micro-combustor has serious heat loss due to its small size, unstable combustion and low combustion efficiency. Aiming at enhancing the heat transfer of the micro-combustor, improving the combustion stability and high-efficiency combustion, this paper embedded porous media in the combustor, and the effects of different parameters on the combustion characteristics were numerically studied. The research results showed that the layout of porous media should be reasonable, and the small and large pore porous media embedded in the inner and outer layers, respectively, can bring better combustion performance. Meanwhile, A: 10–30 has a high and uniform temperature distribution, and its methane conversion rate reached 97.4%. However, the diameter ratio of the inner layer to the outer layer (d/D) of the porous medium should be maintained at 0.4–0.6, which brings a longer gas residence time, and further enables the pre-mixed gas to preheat and burn completely. At a d/D of 0.5, the combustor has the highest outer wall temperature and CH4 conversion efficiency. Besides, compared with the pore size increasing rate of Δn = 10 PPI and Δn = 10 PPI, the radial temperature distribution of the Δn = 10 PPI combustor is more uniform, meanwhile avoids the occurrence of local high temperature. Under the condition of Δn = 10 PPI, A: 20–30 layout maintains excellent thermal and combustion performance. In addition, the lean flammable limits of MC-U20, MC-10/30-0.8, and MC-20/30-0.5 were compared, at an inlet velocity of 0.5 m/s, the corresponding lean flammable limits are 0.5, 0.4, and 0.3, respectively, among them MC-20/30-0.5 has a wider flammable limit range, showing excellent combustion stability. This research has guiding significance for the combustion stability of the micro combustor.

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A numerical study on non-premixed H2/air flame stability in a micro-combustor with a slotted bluff-body

Cited by 38 publications

References 47 publications

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

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

Numerical investigation on combustion flow characteristics of a micro gas turbine swirl combustor with different protruded bluff body structures

Influence of Porous Media Aperture Arrangement on CH4/Air Combustion Characteristics in Micro Combustor

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