Investigation on Flashback Propensity of Syngas Premixed Flames

Davu, Deepthi; Franco, Rogelio; Choudhuri, Ahsan; Lewis, Robie E.

doi:10.2514/6.2005-3585

Cited by 23 publications

(10 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Dam, Love et al, and Davu, Franco et al, also produced laminar flashback data for various syngases, however, their experimental setup was under laminar conditions and very similar to previous works with the exception of the acoustic excitation (Davu, Franco et al 2005;Dam, Love et al 2011). …”

Section: Fundamental Axisymmetric Bunsen/jet Flame Flashback Studiessupporting

confidence: 66%

See 1 more Smart Citation

Fuel Flexible Turbine System (FFTS) Program

None¹

2012

View full text Add to dashboard Cite

Section: Fundamental Axisymmetric Bunsen/jet Flame Flashback Studiessupporting

confidence: 66%

“…An investigation of boundary layer flashback in laminar, syngas fueled Bunsen flames has been detailed by Davu et al (2005). In turbulent combustion, flame propagation along the burner walls is another key flashback mechanism.…”

Section: Boundary Layer Flashbackmentioning

confidence: 99%

Fuel Flexible Turbine System (FFTS) Program

None¹

2012

View full text Add to dashboard Cite

“…Lee et al revealed the connection between Damköhler number and Péclet number analyses; these researchers showed that essentially the expression developed by Putnam was equivalent to the ratio of a characteristic flow time scale and a chemical reaction time scale [19]. Davu et al and Dam et al investigated flashback with a generic injector geometry using syngas fuels while the flames were also subjected to acoustic perturbations [20,21]. Xu Gang et al employed a ring and rod set up to stabilize a very lean premixed flame and investigated the ef^fect of coaxial air flow [22].…”

Section: Introductionmentioning

confidence: 98%

Study of Fuel Composition Effects on Flashback Using a Confined Jet Flame Burner

Shaffer

Duan

McDonell

2012

Journal of Engineering for Gas Turbines and Power

View full text Add to dashboard Cite

Flashback is the main operability issue associated with converting lean, premixed combustion systems from operation on natural gas to operation on high hydrogen content fuels. Most syngas fuels contain some amount of hydrogen (15-100%) depending on the fuel processing scheme. With this variability in the composition of syngas, the question of how fuel composition impacts flashback propensity arises. To address this question, a jet burner configuration was used to develop systematic data for a wide range of compositions under turbulent flow conditions. The burner consisted of a quartz burner tube confined by a larger quartz tube. The use of quartz allowed visualization of the flashback processes occurring. Various fuel compositions of hydrogen, carbon monoxide, and natural gas were premixed with air at equivalence ratios corresponding to constant adiabatic flame temperatures (AFT) of 1700K and 1900K. Once aflame was stabilized on the burner, the air flow rate would be gradually reduced while holding the AFT constant via the equivalence ratio until flashback occurred. Schlieren and intensified OH* images captured at high speeds during flashback allowed some additional understanding of what is occurring during the highly dynamic process of flashback. Confined and unconfined flashback data were analyzed by comparing data collected in the present study with existing data in the literature. A statistically designed test matrix was used which allows analysis of variance of the results to be carried out, leading to correlation between fuel composition and flame temperature with (1) critical flashback velocity gradient and (2) burner tip temperature. Using the burner tip temperature as the unburned temperature in the laminar flame speed calculations showed increased correlation of the flashback data and laminar flame speed as opposed to when the actual unburned gas temperature was tised.

show abstract

“…From the perspective of fuel compositions, it is found that the flashback behavior is dominated by the hydrogen content [10,16,17]. This is attributed to the fact that for the combustible mixtures containing hydrogen, the mass and thermal diffusivities strongly differ among the components.…”

Section: Introductionmentioning

confidence: 89%

Turbulent Flame Speed as an Indicator for Flashback Propensity of Hydrogen-Rich Fuel Gases

Lin¹,

Daniele

Jansohn

et al. 2013

Journal of Engineering for Gas Turbines and Power

View full text Add to dashboard Cite

The turbulent flame speed (S T ) is proposed to be an indicator of the flashback propensity for hydrogen-rich fuel gases at gas turbine relevant conditions. Flashback is an inevitable issue to be concerned about when introducing fuel gases containing high hydrogen content to gas turbine engines, which are conventionally fueled with natural gas. These hydrogen-containing fuel gases are present in the process of the integrated gasification combined cycle (IGCC), with and without precombustion carbon capture, and both syngas (H 2 þ CO) and hydrogen with various degrees of inert dilution fall in this category. Thus, a greater understanding of the flashback phenomenon for these mixtures is necessary in order to evolve the IGCC concept (either with or without carbon capture) into a promising candidate for clean power generation. Compared to syngas, the hydrogen-rich fuel mixtures exhibit an even narrower operational envelope between the occurrence of lean blow out and flashback. When flashback occurs, the flame propagation is found to occur exclusively in the boundary layer of the pipe supplying the premixed fuel/air mixture to the combustor. This finding is based on the experimental investigation of turbulent lean-premixed nonswirled confined jet flames for three fuel mixtures with H 2 > 70 vol. %. Measurements were performed up to 10 bar at a fixed bulk velocity at the combustor inlet (u 0 ¼ 40 m/s) and preheat temperature (T 0 ¼ 623 K). Flame front characteristics were retrieved via planar laser-induced fluorescence of the hydroxyl radical (OH-PLIF) diagnostics and the turbulent flame speed (S T ) was derived, accordingly, from the perspective of a global consumption rate. Concerning the flashback limit, the operational range of the hydrogen-rich mixtures is found to be well represented by the velocity gradients prescribed by the flame (g c ) and the flow (g f ), respectively. The former (g c ) is determined as S T /(Le Â d L0 ), where Le is the Lewis number and d L0 is the calculated thermal thickness of the one-dimensional laminar flame. The latter (g f ) is predicted by the Blasius correlation for fully developed turbulent pipe flow and it indicates the capability with which the flow can counteract the opposed flame propagation. Our results show that the equivalence ratios at which the two velocity gradients reach similar levels correspond well to the flashback limits observed at various pressures. The methodology is also found to be capable of predicting the aforementioned difference in the operational range between syngas and hydrogen-rich mixtures.

show abstract

Investigation on Flashback Propensity of Syngas Premixed Flames

Cited by 23 publications

References 6 publications

Fuel Flexible Turbine System (FFTS) Program

Fuel Flexible Turbine System (FFTS) Program

Study of Fuel Composition Effects on Flashback Using a Confined Jet Flame Burner

Turbulent Flame Speed as an Indicator for Flashback Propensity of Hydrogen-Rich Fuel Gases

Contact Info

Product

Resources

About