Numerical Simulations of Confined, Turbulent, Lean, Premixed Flames Using a Detailed Chemistry Combustion Model

An experimental analysis of confined premixed turbulent methane/air and hydrogen/air jet flames is presented. A generic lab scale burner for high-velocity preheated jets equipped with an optical combustion chamber was designed and set up. The size and operating conditions were configured to enable flame stabilization by recirculation of hot combustion products. The geometry of the rectangular confinement and an off-center positioning of the jet nozzle were chosen to resemble one burner nozzle of a FLOX V Rbased combustor. The off-center jet arrangement caused the formation of a pronounced lateral recirculation zone similar to the one in previously investigated FLOX V R -combustors (Lückerath et al., 2007. "FLOX V R Combustion at High Pressure with Different Fuel Compositions," ASME J. Eng. Gas Turbines Power, 130(1), pp. 011505; Lammel et al., 2010. "FLOX V R Combustion at High Power Density and High Flame Temperatures," ASME J. Eng. Gas Turbines Power, 132(12), p. 121503ff). The analysis was accomplished by different laser measurement techniques. Flame structures were visualized by OH* chemiluminescence imaging and planar laser-induced fluorescence of the OH radical. Laser Raman scattering was used to determine concentrations of the major species and the temperature. Velocity fields were measured with particle image velocimetry. Results of measurements in two confined jet flames are shown. The mixing of fresh gas with recirculating combustion products and the stabilization of the methane flame are discussed in detail. The presented findings deliver important information for the understanding of confined jet flames operated with different fuels. The obtained data sets can be used for the validation of numerical simulations as well.

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“…The attained results were used as validation data for numerical simulations as well (see Di Domenico et al [17]). …”

Section: Introductionmentioning

confidence: 99%

Experimental Analysis of Confined Jet Flames by Laser Measurement Techniques

Lammel

Stöhr

Kutne

et al. 2012

Journal of Engineering for Gas Turbines and Power

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“…The simplest model combustor is a lab-scale single nozzle burner, that has extensively been investigated at atmospheric conditions, both experimentally [11,12] and numerically [13]. Furthermore, a 3-nozzle model combustor has been investigated at high pressure [8].…”

Section: Introductionmentioning

confidence: 99%

High Momentum Jet Flames at Elevated Pressure: B — Detailed Investigation of Flame Stabilization With Simultaneous PIV and OH-LIF

Severin

Lammel

et al. 2017

Volume 4B: Combustion, Fuels and Emissions

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A model FLOX ® combustor, featuring a single high momentum premixed jet flame, has been investigated using laser diagnostics in an optically accessible combustion chamber at a pressure of 8 bar. The model combustor was designed as a large single eccentric nozzle main burner (Ø 40 mm) together with an adjoining pilot burner and was operated with natural gas.To gain insight into the flame stabilization mechanisms with and without piloting, simultaneous Particle Image Velocimetry (PIV) and OH Laser Induced Fluorescence (LIF) measurements have been performed at numerous two-dimensional sections of the flame. Additional OH-LIF measurements without PIV-particles were analyzed quantitatively resulting in absolute OH concentrations and temperature fields.The flow field looks rather similar for both the unpiloted and the piloted case, featuring a large recirculation zone next to the high momentum jet. However, flame shape and position change drastically. For the unpiloted case, the flame is lifted, widely distributed and isolated flame kernels are found at the flame root in the vicinity of small scale vortices. For the piloted flame, on the other hand, both pilot and main flame are attached to the burner base plate, and flame stabilization seems to take place on much smaller spatial scales with a connected flame front and no isolated flame kernels.The single shot analysis gives rise to the assumption that for the unpiloted case small scale vortices act like the pilot burner flow in the opposed case and constantly impinge and ignite the high momentum jet at its root.

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“…The numerical method presented in this paper is an extension of the incompressible projection method incorporated in the DLR in-house combustion CFD code THETA 8,9 (Turbulent Heat Release Extension of the TAU code). THETA is based on a three dimensional finite volume discretization method and includes a dual grid approach, thus allowing the calculation of flows on structured, unstructured and hybrid grids.…”

Section: The Theta Codementioning

confidence: 99%

Development of a Projection-Based Method for the Numerical Calculation of Compressible Reactive Flows

Reichling

Noll

Aigner

2013

51st AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition

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The ability to calculate compressible reactive flows enables the computation of thermoacoustic interactions in gas turbine combustor systems. A new projection-based numerical method able to compute compressible reactive flows is developed within this work. This computational scheme is based on a modified Helmholtz decomposition, by which an arbitrary vector field is split up into a field with a so-called divergence constraint and an irrotational field. This leads to a fractional step scheme which consists of a predictor and a corrector step. The Poisson equation solved for the pressure in case of incompressible flows is extended to a Helmholtz equation for the computation of compressible flows. After solving the corrector step, the mass and momentum balances are fulfilled. This results in a fast numerical scheme, since no further iterations need to be computed. Based on the modified Helmholtz decomposition, it is shown that the created method can be understood as an extension of the incompressible projection scheme. Moreover, the spatial and temporal order of accuracy of incompressible projection-based methods are discussed and the ones of the compressible scheme are determined. The created compressible projection-based method is further on validated against a one-dimensional linear acoustic test case from the literature, whereby an analytical solution can be derived.

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Numerical Simulations of Confined, Turbulent, Lean, Premixed Flames Using a Detailed Chemistry Combustion Model

Cited by 28 publications

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Experimental Analysis of Confined Jet Flames by Laser Measurement Techniques

Experimental Analysis of Confined Jet Flames by Laser Measurement Techniques

High Momentum Jet Flames at Elevated Pressure: B — Detailed Investigation of Flame Stabilization With Simultaneous PIV and OH-LIF

Development of a Projection-Based Method for the Numerical Calculation of Compressible Reactive Flows

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