Isothermal coherent structures and turbulent flow produced by a gas turbine combustor lean pre-mixed swirl fuel nozzle

Gomez-Ramirez, David; Ekkad, Srinath V.; Moon, Hee-Koo; Kim, Yong; Srinivasan, Ram

doi:10.1016/j.expthermflusci.2016.10.010

Cited by 18 publications

(4 citation statements)

References 31 publications

(78 reference statements)

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“…including the coherent and stochastic vortical structures forming downstream of the nozzle, can be found in Gomez-Ramirez et al [32]. Downstream of the impingement point the swirling jet attached to the wall, and subsequent boundary layer growth led to a decrease in the heat transfer.…”

Section: Steady State Heat Transfer At Different Reynolds Numbersmentioning

confidence: 91%

“…These measurements support the heat transfer results and provide details on the size of the corner recirculation and approximate location of flow reattachment. Further information on the steady and unsteady flow field within the combustor model at isothermal conditions can be found in Gomez-Ramirez et al [32]. For the measurements, a Nano-L 135-15 Nd:YAG dual laser system with a Flowsense 4M MKII camera and control software from Dantec Dynamics were used.…”

Section: Supporting Flow Measurements Using Pivmentioning

confidence: 99%

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Investigation of isothermal convective heat transfer in an optical combustor with a low-emissions swirl fuel nozzle

Gomez-Ramirez

Kedukodi

Ekkad

et al. 2017

Applied Thermal Engineering

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Modern combustor design optimization is contingent on the accurate characterization of the combustor flame side heat loads. The present work focuses on the experimental measurement of the isothermal (non-reacting) convective heat transfer along a fused silica optical can combustor liner for Reynolds numbers ranging between 11 500 and 138 000. The model combustor was equipped with the SoLoNOx swirl fuel nozzle from Solar Turbines Incorporated, subjecting the liner walls to realistic isothermal flow and turbulence fields. Infrared (IR) imaging through fused silica was demonstrated, and a novel estimation of the three-dimensional conduction heat losses for steady state constant heat flux experiments was developed. A maximum heat transfer augmentation of ~18 was observed with respect to fully developed turbulent pipe flow correlations. Contrary to other investigations, the augmentation magnitude and distribution are shown to be approximately constant with Reynolds number (particularly away from the impingement location). Particle Image Velocimetry (PIV) was included to support the heat transfer measurements, suggesting that peak heat transfer occurred 0.12 nozzle diameters upstream of the jet reattachment point along the liner. Reynolds-Averaged Navier Stokes (RANS) computations are shown to yield peak heat transfer predictions within 17.4% of the experimental results when using the realizable k-ε turbulence model and enhanced wall treatment. The measurements were further analyzed in the context of results from other heat transfer studies on gas turbine combustors.

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Section: Steady State Heat Transfer At Different Reynolds Numbersmentioning

confidence: 91%

Section: Supporting Flow Measurements Using Pivmentioning

confidence: 99%

Investigation of isothermal convective heat transfer in an optical combustor with a low-emissions swirl fuel nozzle

Gomez-Ramirez

Kedukodi

Ekkad

et al. 2017

Applied Thermal Engineering

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“…[1][2][3] Especially in combustion, the most recent optical diagnostics can be employed to provide not only information about the flow field through multidimensional particle image velocimetry measurements but also high frequency acquisitions of the reactant species distribution via natural chemiluminescence or induced fluorescence. 4,5 From the numerical standpoint, the adoption of high-fidelity multi-physics approaches is paving the way to the so-called "virtual testing" that provides the possibility to extract the same kind of information in any desired location of the three-dimensional domain: in this case the management of the fluxes of data can become even more challenging. 6,7 The availability of all these data can be leveraged trying to correlate different quantities and gain information aiming to characterize the behavior of a given combustor design in a wide range of operating conditions.…”

Section: Introductionmentioning

confidence: 99%

E-POD investigations of turbulent premixed flame dynamics approaching lean blow-out conditions

Meloni¹,

Chiarizia

Nassini

et al. 2023

International Journal of Spray and Combustion Dynamics

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Thanks to the continuous computational power increase, the use of high-fidelity computational fluid dynamics (CFD) simulations is nowadays customary, especially in the gas turbines design process. The extraordinary temporal and spatial detail of such analyses generate large datasets, which must be carefully studied to correlate different quantities and gain information to characterize the behavior of combustor designs. Several advanced post-processing tools have been proposed; however, the Extended-POD (E-POD) holds the greatest potential for turbulent combustion applications when the mutual influence of different quantities is the main goal of the investigation. The present work investigates the application of the E-POD to an LES model of a perfectly-premixed, swirl-stabilized, methane-air flame approaching Lean-Blow-Out. Leveraging the validation against the experimental data at two different operating conditions on a laboratory test case, the numerical model has been used to collect several quantities of interest for shedding light on the flow-flame interaction near the blow-out. The post-processing algorithm has been used to highlight the differences between two conditions approaching the extinction at distinct air-flow velocities. It has been found that, when the burner is operated with a higher velocity, the flame is subjected to a cyclic low-frequency breakdown around the internal recirculation zone, leading to an ingestion of cold products from the external parts of the combustor toward the center. Although other local effects acting on the flame brush have been found in both conditions, they are related mainly to higher order coherent structures with a lower energy content. As a result, their impact onto flame stability is found to be of secondary importance since their limited interaction with flame stabilization. The work shows that E-POD represents a powerful tool for investigating the key features of flame dynamics even at near-blow-out conditions, constituting a valid algorithm for interpreting the results of CFD analyses on gas turbines combustors.

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“…In addition, aerodynamic parameters, such as pressure and mass flow rate, could affect the frequency of PVC [19]. When PVC existed, it could effectively improve fuel-air mixing, further enhancing flame stability [20]. Several investigations have been carried out to study the effect of PVC on flame stabilization.…”

Section: Introductionmentioning

confidence: 99%

Modal Decomposition Study of the Non-Reactive Flow Field in a Dual-Swirl Combustor

Feng,

Suo,

et al. 2023

Energies

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The modal decomposition study of the non-reactive flow field in a dual-swirl combustor is investigated through the large eddy simulation. The formation mechanism and function of various recirculation zones are elaborated by analyzing the time-averaged and instantaneous velocity contours of the center section. The precessing vortex core (PVC) is first visualized by the pressure iso-surface, and the evolution process is presented. Different dimensionality reduction methods are adopted to identify the coherent structures from the flow field. The most energetic spatial structure corresponding to the PVC and its second-order harmonic structure is extracted by the classical proper orthogonal decomposition (POD). The coherent structures with high frequency have relatively low energy content. In addition, a spectral proper orthogonal decomposition (SPOD) method, which can implement spatial-temporal decomposition simultaneously, is introduced to obtain the energy-based spatial structures at all characteristic frequencies. A triple-helix with azimuth wave number m = 3 and a quadruple-helix with azimuth wave number m = 4 are discovered as the third-order and the fourth-order harmonics of single-helix, respectively.

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Isothermal coherent structures and turbulent flow produced by a gas turbine combustor lean pre-mixed swirl fuel nozzle

Cited by 18 publications

References 31 publications

Investigation of isothermal convective heat transfer in an optical combustor with a low-emissions swirl fuel nozzle

Investigation of isothermal convective heat transfer in an optical combustor with a low-emissions swirl fuel nozzle

E-POD investigations of turbulent premixed flame dynamics approaching lean blow-out conditions

Modal Decomposition Study of the Non-Reactive Flow Field in a Dual-Swirl Combustor

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