Impact of Flame–Flame Interactions in Identical Twin Diffusion Microflames

Hirasawa, Takashi; Gotanda, Kunihiro; Masuda, H.; Nakamura, Yuji

doi:10.1080/00102202.2012.699362

Cited by 20 publications

(4 citation statements)

References 14 publications

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“…The double-jet flame shows four states of fully independent flame, tilted separated flame, semicombined flame, and fully combined flame in turn, when the burner pitch increased, as shown in Figure 23 . This change process is consistent with the flame incorporation behavior of hydrocarbon fuels studied by Hirasawa et al 51 In this paper, it was found that for a fuel composition of 50%CH 4 –50%NH 3 , the two flames completely are two separate flames when the burner pitch is 6 mm. The two separated flames are tilted inward and are in a tilted separation state when the burner pitch decreases to 4 mm.…”

Section: Resultssupporting

confidence: 90%

CH₄/NH₃ Flame Structure and Extinction Limit under Flame–Flame Interactions

Meng,

Chen,

Zheng

et al. 2024

ACS Omega

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Ammonia is considered to play an important role in replacing traditional fossil fuels in future energy systems. In the experimental study, CH4/NH3 flame was lit by applying a double-nozzle burner to gain insight into the structure, and the laminar diffusion flame structure, CH*/OH* intensity maximum, and flame size were analyzed by an ICCD camera. In addition, the extinction limit (lower limit) of the CH4/NH3 flame under different conditions was also studied. The results showed that with the increase of burner pitch, the two diffusion flames showed four states of merged flames, merging flames, inclining separated flames, and independent flames in turn. In the process of flame separation, the continuous pitch between merging flames was short. At this point, higher syngas flow could help increase the continuous pitch to keep merging form. The paper investigated the flame structure and found that the flame size would decrease when the NH3 content in the fuel was high. The flame stability also decreased with an increase of the NH3 content in the fuel. These findings provided experimental proof and a theoretical basis for future studies on the stability of CH4/NH3 co-firing.

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Section: Resultssupporting

confidence: 90%

CH₄/NH₃ Flame Structure and Extinction Limit under Flame–Flame Interactions

Meng,

Chen,

Zheng

et al. 2024

ACS Omega

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“…Others have shown that multiple micro-flames may be used to enhance heating performance with special attention to flame–flame interactions that can induce undesirable merging of the individual flames (Hirasawa et al. 2012; Kuwana et al. 2014).…”

Section: Introductionmentioning

confidence: 99%

“…Additionally, microjet configurations are attractive for future micro-power devices due to low soot production and high energy density resulting from a large surface-to-volume ratio. Others have shown that multiple micro-flames may be used to enhance heating performance with special attention to flame-flame interactions that can induce undesirable merging of the individual flames (Hirasawa et al 2012;Kuwana et al 2014).…”

Section: Introductionmentioning

confidence: 99%

Dynamics of acoustically coupled single- and multi-port jet diffusion flames

Vargas,

Kiani,

Hayrapetyan

et al. 2023

J. Fluid Mech.

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The present experimental study investigated the dynamics of single- and multi-port gaseous jet diffusion flames exposed to acoustic excitation via a standing wave situated in a closed waveguide at atmospheric pressure. High-speed imaging of the oscillatory flame was analysed via proper orthogonal decomposition (POD), revealing distinct signatures in both mode shapes and phase portraits for transitions in the acoustically coupled combustion process. For Reynolds numbers between 20 and 100, and for low to moderate forcing amplitudes, the flame exhibited sustained oscillatory combustion (SOC) that was highly coupled to the acoustic forcing. Frequency analysis of the temporal POD modes accurately recovered the forcing frequency and its higher harmonics. At higher forcing amplitudes, a multi-frequency response was observed, resulting from a combination of the forcing frequency and much lower frequency oscillations due to periodic lift-off and reattachment (PLOR) of the flame, preceding a transition to flame blow-off (BO). For both single- and triple-jet flames, transitions from SOC to PLOR to BO were characterized by significant alterations in primary modal energetic content, deflection and eventual smearing in phase portraits, and the development of additional frequencies in modal spectra, although transitional behaviour for the triple jet flames involved additional complexity in the dynamics due to its structure. These features provide the potential for the development of reduced-order models that can characterize and predict acoustically coupled combustion behaviour.

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“…Laminar jet diffusion flames of liquid ethanol were stabilized by submillimeter tubes, as shown in the studies by Chen , et al (2009) andXu, et al (2013). Additionally, motivated by developing a multiple arrayed microflame burner, the interactions of microflames have been studied by Hirasawa, et al (2012) and Kuwana, et al (2016). Most recently, an extremely small flamelet was made by using a counterflow configuration to burn methane with pure oxygen by Kadowaki, et al (2016).…”

Section: Instability and Othersmentioning

confidence: 99%

Progress in small-scale combustion

Nakamura

Gao

Matsuoka

2017

JTST

Self Cite

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This article briefly reviews the recent works related to small-scale combustion and its potential impact into combustion science and engineering is presented. Followed by a simple description of the scale effect on combustion to highlight its "unique" feature, past related works are then summarized. The impact of heat recirculation appearing in combustion systems, which is the most prominent feature of a micro-or small-scale combustion system, is focused upon and is understood that exactly the same strategy promising better combustion performance is confirmed irrespective of flame type (either premixed or non-premixed). With respect to this, paying attention to the entire combustor design, to optimize within the target working range is a crucial matter when micro-scale combustion is adopted. Potential subjects to be covered to further promote these aspects in this field are then presented.

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Impact of Flame–Flame Interactions in Identical Twin Diffusion Microflames

Cited by 20 publications

References 14 publications

CH₄/NH₃ Flame Structure and Extinction Limit under Flame–Flame Interactions

CH₄/NH₃ Flame Structure and Extinction Limit under Flame–Flame Interactions

Dynamics of acoustically coupled single- and multi-port jet diffusion flames

Progress in small-scale combustion

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Impact of Flame–Flame Interactions in Identical Twin Diffusion Microflames

Cited by 20 publications

References 14 publications

CH4/NH3 Flame Structure and Extinction Limit under Flame–Flame Interactions

CH4/NH3 Flame Structure and Extinction Limit under Flame–Flame Interactions

Dynamics of acoustically coupled single- and multi-port jet diffusion flames

Progress in small-scale combustion

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Product

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CH₄/NH₃ Flame Structure and Extinction Limit under Flame–Flame Interactions

CH₄/NH₃ Flame Structure and Extinction Limit under Flame–Flame Interactions