Flame/wall interaction and maximum wall heat fluxes in diffusion burners

Lataillade, A. de; Dabireau, François; Cuenot, Bénédicte; Poinsot, Thiérry

doi:10.1016/s1540-7489(02)80099-2

Cited by 22 publications

(6 citation statements)

References 11 publications

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“…For the systems in which walls and flame interact, significant unsteady heat transfer occurs due to a very large temperature gradient (flame temperature is usually in the range of 1500 K to 2500 K while the wall temperature remains between 400 K to 600 K because of cooling). This can affect the efficiency and pollution formation of the flame and also the life time of the chamber (Delataillade et al, 2002;Dabireau et al, 2003). As mentioned above the inner diameter of the chamber (30 cm) is much bigger than the size of the burner (3.81 cm) and the flame width (roughly 6-9 cm).…”

Section: Test Facilitiesmentioning

confidence: 98%

Flame structure and thermo-acoustic coupling for the low swirl burner for elevated pressure and syngas conditions

Emadi¹

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Reduction of the pollutant emissions is a challenge for the gas turbine industry. A solution to this problem is to employ the low swirl burner which can operate at lower equivalence ratios than a conventional swirl burner. However, flames in the lean regime of combustion are susceptible to flow perturbations and combustion instability. Combustion instability is the coupling between unsteady heat release and combustor acoustic modes where one amplifies the other in a feedback loop. The other method for significantly reducing NO x and CO 2 is increasing fuel reactivity, typically done through the addition of hydrogen. This helps to improve the flammability limit and also reduces the pollutants in products by decreasing thermal NO x and reducing CO 2 by displacing carbon. In this work, the flammability limits of a low swirl burner at various operating conditions, is studied and the effect of pressure, bulk velocity, burner shape and percent of hydrogen (added to the fuel) is investigated. Also, the flame structure for these test conditions is measured using OH planar laser induced fluorescence and assessed. Also, the OH PLIF data is used to calculate Rayleigh index maps and to construct averaged OH PLIF intensity fields at different acoustic excitation frequencies (45-155, and 195Hz). Based on the Rayleigh index maps, two different modes of coupling between the heat release and the pressure fluctuation were observed: the first mode, which occurs at 44Hz and 55Hz, shows coupling to the flame base (due to the bulk velocity) while the second mode shows coupling to the sides of the flame. In the first mode, the flame becomes wider and the flame base moves with the acoustic frequency. In the second mode, imposed pressure oscillations induce vortex shedding in the flame shear layer. These vortices distort the flame front and generate locally compact and sparse flame areas. The local flame structure resulting from these two distinct modes was markedly different.

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Section: Test Facilitiesmentioning

confidence: 98%

Flame structure and thermo-acoustic coupling for the low swirl burner for elevated pressure and syngas conditions

Emadi¹

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“…The interaction between flames and walls controls combustion, pollution and wall heat fluxes in a significant manner [10,14,15]. It also determines the wall temperature and its life time.…”

Section: Flame/wall Interaction (Fwi)mentioning

confidence: 99%

Conjugate heat transfer with Large Eddy Simulation for gas turbine components

Duchaine

Mendez

Nicoud³

et al. 2009

Comptes Rendus. Mécanique

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International audienceCHT (Conjugate Heat Transfer) is a main design constraint for GT (gas turbines). Most existing CHT tools are developed for chained, steady phenomena. A fully parallel environment for CHT has been developed and applied to two configurations of interest for the design of GT. A reactive Large Eddy Simulations code and a solid conduction solver exchange data via a supervisor. A flame/wall interaction is used to assess the precision and the order of the coupled solutions. A film-cooled turbine vane is then studied. Thermal conduction in the blade implies lower wall temperature than adiabatic results and CHT reproduces the experimental cooling efficiency

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“…Many numerical studies have been conducted on laminar flame-wall interactions [6][7][8][9][10] . It has been shown by Popp et al [9] that in the low wall temperature regime (300 K < T w < 400 K) the wall can be assumed chemically inert.…”

Section: Introductionmentioning

confidence: 99%

Effect of pressure on hydrogen/oxygen coupled flame–wall interaction

Mari

Cuenot

Rocchi

et al. 2016

Combustion and Flame

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The design and optimization of liquid-fuel rocket engines is a major scientific and technological challenge. One particularly critical issue is the heating of solid parts that are subjected to extremely high heat fluxes when exposed to the flame. This in turn changes the injector lip temperature, leading to possibly different flame behaviors and a fully coupled system. As the chamber pressure is usually much larger than the critical pressure of the mixture, supercritical flow behaviors add even more complexity to the thermal problem. When simulating such phenomena, these thermodynamic conditions raise both modeling and numerical specific issues. In this paper, both subcritical and supercritical hydrogen/oxygen one-dimensional, laminar flames interacting with solid walls are studied by use of conjugate heat transfer simulations, allowing to evaluate the wall heat flux and temperature, their impact on the flame as well as their sensitivity to high pressure and real gas thermodynamics up to 100 bar where real gas effects are important. At low pressure, results are found in good agreement with previous studies in terms of wall heat flux and quenching distance, and the wall stays close to isothermal. On the contrary, due to important changes of the fluid transport properties and the flame characteristics, the wall experiences significant heating at high pressure condition and the flame behavior is modified.

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Flame/wall interaction and maximum wall heat fluxes in diffusion burners

Cited by 22 publications

References 11 publications

Flame structure and thermo-acoustic coupling for the low swirl burner for elevated pressure and syngas conditions

Flame structure and thermo-acoustic coupling for the low swirl burner for elevated pressure and syngas conditions

Conjugate heat transfer with Large Eddy Simulation for gas turbine components

Effect of pressure on hydrogen/oxygen coupled flame–wall interaction

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