Effects of fuel type and equivalence ratios on the flickering of triple flames

Sahu, Kunja Bihari; Kundu, Atanu; Ganguly, Ranjan; Datta, Amitava

doi:10.1016/j.combustflame.2008.11.017

Cited by 32 publications

(24 citation statements)

References 39 publications

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“…It was observed that several peak spectrum values with a certain amount of amplitude exist in the low-frequency domain, mainly in the range of 0-50 Hz. Compared to the single-peak spectrum for flame with no swirl in previous researches [1,3], current spectrum observed in this research could have occurred due to the effect of swirl on flame oscillation. In spite of the multiple peak values emerging on the graph, one distinct peak value corresponding to the main frequency always can be found for each condition.…”

Section: Frequency and Amplitude Versus Fuel Mass Flow Ratementioning

confidence: 92%

“…It is mainly caused by the upward convection of large toroidal vortices, which are driven by buoyancy induced by combustion [1,3]. The pulsation process can be seen in Figure 4.…”

Section: Flame Dynamicsmentioning

confidence: 99%

“…Under severe cases, the flickering can result in the extinction of the flame and the combustion device's failure, such as a gas turbine combustor and boiler furnace. Therefore, understanding flame oscillatory behavior is significant to the combustion community [3].…”

Section: Introductionmentioning

confidence: 99%

“…Flame puffing frequency is usually correlated by Strouhal number St, Froude number Fr, and Reynolds number Re, which are defined as Equations (1)- (3).…”

Section: Introductionmentioning

confidence: 99%

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An Experimental Investigation on Flame Pulsation for a Swirl Non-Premixed Combustion

et al. 2018

Energies

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Flame pulsation has a significant effect on combustion, and understanding its oscillatory behavior is important to the combustion community. An experiment was performed to analyze the pulsation characteristics of a swirl non-premixed flame under various parameters. The results showed that as fuel mass flow rate increased, the puffing frequency increased due to the decreased flame radiation fraction, and the puffing amplitude became smaller resulting in a more stable flame. With an increase in combustor pressure, the flickering frequency declined because of the increasing soot radiation, while the flickering amplitude uniformly increased, leading to more deteriorative flame stability. With an increment in mass flow rate of primary air, the puffing frequency decreased due to the enhanced mixing between fuel and primary air. Also, the puffing amplitude had an oscillating relationship with the mass flow rate of primary air. When the exit velocity of the injector was increased, the flickering frequency diminished nearly linearly because of the improving swirl intensity, and the flickering amplitude was approximately unaffected by injector exit velocity. Moreover, the measured puffing frequencies summarized over all cases varied within the range of 3-22 Hz, the predicted values from theoretical models based on non-swirl flame also fell within this range. The puffing frequency of swirl combustion was more sensitive to the variation in operating conditions than that of non-swirl combustion. Additionally, the obtained correlations indicated that the Strouhal number St was proportional to Fr −1.4 (the Froude number) and Re −2.9 (the Reynolds number), respectively.

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Section: Frequency and Amplitude Versus Fuel Mass Flow Ratementioning

confidence: 92%

“…It is mainly caused by the upward convection of large toroidal vortices, which are driven by buoyancy induced by combustion [1,3]. The pulsation process can be seen in Figure 4.…”

Section: Flame Dynamicsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…Flame puffing frequency is usually correlated by Strouhal number St, Froude number Fr, and Reynolds number Re, which are defined as Equations (1)- (3).…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

An Experimental Investigation on Flame Pulsation for a Swirl Non-Premixed Combustion

et al. 2018

Energies

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“…Lewis numbers less than one was caused by thermal diffusion and a hydrodynamic instability so that cellular flame occurred (Kadowaki 2005). Co-flow type was used to see triple flame with different equivalence ratio of the reactants flow on inner and outer burner (Sahu et al 2009). …”

Section: Introductionmentioning

confidence: 99%

Premixed Combustion of Kapok (ceiba pentandra) seed oil on Perforated Burner

Wirawan

Wardana

Soenoko

et al. 2014

Int. J. Renew. Energy Dev.

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Availability of fossil fuels in the world decrease gradually due to excessive fuel exploitation. This situations push researcher to look for alternative fuels as a source of renewable energy, one of them is kapok (ceiba pentandra) seed oil. The aim this study was to know the behavior of laminar burning velocity, secondary Bunsen flame with open tip, cellular and triple flame. Premixed combustion of kapok seed oil was studied experimentally on perforated burner with equivalence ratio (φ) varied from 0.30 until 1.07. The results showed that combustion of glycerol requires a large amount of air so that laminar burning velocity (SL) is the highest at very lean mixture (φ =0.36) in the form of individual Bunsen flame on each of the perforated plate hole. Perforated and secondary Bunsen flame both reached maximum SL similar with that of ethanol and higher than that of hexadecane. Slight increase of φ decreases drastically SL of perforated and secondary Bunsen flame. When the mixture was enriched, secondary Bunsen and perforated flame disappears, and then the flame becomes Bunsen flame with open tip and triple flame (φ = 0.62 to 1.07). Flame was getting stable until the mixture above the stoichiometry. Being isolated from ambient air, the SL of perforated flame, as well as secondary Bunsen flame, becomes equal with non-isolated flame. This shows the decreasing trend of laminar burning velocity while φ is increasing. When the mixture was enriched island (φ = 0.44 to 0.48) and petal (φ = 0.53 to 0.62) cellular flame take place. Flame becomes more unstable when the mixture was changed toward stoichiometry.

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Image analysis of flame behavior for polyolefins and polystyrene in vertical flame test

Hosokawa

Nakashima

Ueno

2020

J of Applied Polymer Sci

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Although the UL-94 vertical flame test is often used to evaluate the flammability of polymers based on ignition time and combustion duration parameters, a significant amount of information regarding the time course of combustion is difficult to analyze in detail. Herein, image analysis of the time course of the upper and lower end heights, total area, and color division of flame was performed for polyolefins and polystyrene with different molecular weights in the vertical flame test. The combustion process was classified into two stages: before and after the first drip. In the first stage, the upward spread velocity, oscillation, and color of flame were analyzed. It was assumed that the difference in the fuel production rates or thermal decomposition products depends on the molecular structure. In the second stage, the melt flowability, flame position, and combustion continuity differed vastly depending on the molecular structure or molecular weight.

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Effects of fuel type and equivalence ratios on the flickering of triple flames

Cited by 32 publications

References 39 publications

An Experimental Investigation on Flame Pulsation for a Swirl Non-Premixed Combustion

An Experimental Investigation on Flame Pulsation for a Swirl Non-Premixed Combustion

Premixed Combustion of Kapok (ceiba pentandra) seed oil on Perforated Burner

Image analysis of flame behavior for polyolefins and polystyrene in vertical flame test

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