Mixing analysis of a swirling recirculating flow using DNS and experimental data

Freitag, M.; Klein, Markus; Gregor, Mark; Geyer, D.; Schneider, Christoph; Dreizler, Andreas; Janicka, J.

doi:10.1016/j.ijheatfluidflow.2006.02.020

Cited by 41 publications

(26 citation statements)

References 24 publications

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“…Turbulent swirl flows were simulated from the 1990s based on the k − model, algebraic Reynolds stress models (ARSM), and full Reynolds stress models (RSM) [91] but k − models generally require further modifications to accurately predict swirling flows, as they cannot capture anisotropy or strong streamline curvature. Later simulations of swirl flows with recirculation and VB used DNS to investigate the flow in great detail [27,45,72].…”

Section: Studies Of Vortex Breakdownmentioning

confidence: 99%

Large Eddy Simulations of Swirling Non-premixed Flames With Flamelet Models: A Comparison of Numerical Methods

Kempf

Malalasekera

Ranga-Dinesh

et al. 2008

Flow Turbulence Combust

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This work investigates the application of large eddy simulation (LES) to selected cases of the turbulent non-premixed Sydney swirl flames. Two research groups (Loughborough University, LU and Imperial College, IC) have simulated these cases for different parameter sets, using two different and independent LES methods. The simulations of the non-reactive turbulent flow predicted the experimental results with good agreement and both simulations captured the recirculation structures and the vortex breakdown without major difficulties. For the reactive cases, the LES predictions were less satisfactory, and using two independent simulations has helped to understand the shortcomings of each. Furthermore one of the flames (SMH2) was found to be exceptionally hard to predict, which was supported by the lower amount of turbulent kinetic energy that was resolved in this case. However, the LES has identified modes of flame instability that were similar to those observed in some of the experiments.

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Section: Studies Of Vortex Breakdownmentioning

confidence: 99%

Large Eddy Simulations of Swirling Non-premixed Flames With Flamelet Models: A Comparison of Numerical Methods

Kempf

Malalasekera

Ranga-Dinesh

et al. 2008

Flow Turbulence Combust

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“…Moreover, Patil and Tafti [14] implemented LES to simulate complex high Reynolds number swirl flows, where the wall model and the synthetic eddy method were utilized to reduce computational resource. Additionally, DNS results of fluid flow and mixing of a recirculating swirling flow at moderate Reynolds number were compared to experimental data [17]. An overall good agreement between DNS and experiment was shown.…”

Section: Introductionmentioning

confidence: 92%

Direct Numerical Simulation of Twin Swirling Flow Jets: Effect of Vortex-Vortex Interaction on Turbulence Modification

Gui

et al. 2014

Journal of Computational Engineering

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A direct numerical simulation (DNS) was carried out to study twin swirling jets which are issued from two parallel nozzles at a Reynolds number of Re = 5000 and three swirl levels of = 0.68, 1.08, and 1.42, respectively. The basic structures of vortex-vortex interaction and temporal evolution are illustrated. The characteristics of axial variation of turbulent fluctuation velocities, in both the near and far field, in comparison to a single swirling jet, are shown to explore the effects of vortex-vortex interaction on turbulence modifications. Moreover, the second order turbulent fluctuations are also shown, by which the modification of turbulence associated with the coherent or correlated turbulent fluctuation and turbulent kinetic energy transport characteristics are clearly indicated. It is found that the twin swirling flow has a fairly strong localized vortex-vortex interaction between a pair of inversely rotated vortices. The location and strength of interaction depend on swirl level greatly. The modification of vortex takes place by transforming largescale vortices into complex small ones, whereas the modulation of turbulent kinetic energy is continuously augmented by strong vortex modification.

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“…In a number of recent studies, Large-Eddy Simulations [2] and Direct Numerical Simulations [3,4] were used to study the patterns of flow and mixing which occur in recirculating swirling flows. Such simulation strategies, while having the potential of becoming practical simulations tools with the rapid advances in computing power, remain somewhat impractical for routine engineering design which still relies on the solution of Reynoldsaveraged equations with associated turbulence closures.…”

Section: Introductionmentioning

confidence: 99%

Prediction of momentum and scalar transport in turbulent swirling flows with an objective Reynolds-stress transport closure

Younis

Vögler

2009

Heat Mass Transfer

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The accurate prediction of turbulent swirling flows requires the use of a differential Reynolds-stress transport model to close the time-averaged Navier-Stokes equations. The performance of such model is largely determined by the way in which the fluctuating pressurestrain correlations are approximated. A number of alternative approximations are available, all of which depend explicitly on the mean vorticity tensor. Such dependence renders a constitutive relation inconsistent with the principle of Material Frame Indifference (MFI). In this paper, an objective model (i.e. one which is consistent with MFI) for the pressure-strain correlations is presented. This model, which was developed using Tensor Representation Theory, has fewer terms than the conventional alternatives and is therefore easier to implement in computational codes. Moreover, the model was calibrated to correctly reproduce the relative stress levels in both free and wall-bounded flows without the need to employ wall-damping corrections. The performance of this model is assessed using experimental data from both weakly-and strongly-swirled jets. Comparisons are also made with results obtained using three widely-used alternative models for the pressure-strain correlations. It is found that the objective model, although simpler in formulation than the others, yields results that are generally in closer correspondence with the data. The paper also reports on the prediction of mass transfer in a swirling jet. The case considered was that of a co-axial, stronglyswirled flow with an outer annular air stream and an inner helium jet. Swirl was imparted to the outer stream only. The concentration of helium was predicted using a differential scalar-flux transport closure. Close agreement was obtained with the measured concentrations. Analysis of the predicted mass fluxes revealed that the turbulent diffusivity is strongly anisotropic in this flow.

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Mixing analysis of a swirling recirculating flow using DNS and experimental data

Cited by 41 publications

References 24 publications

Large Eddy Simulations of Swirling Non-premixed Flames With Flamelet Models: A Comparison of Numerical Methods

Large Eddy Simulations of Swirling Non-premixed Flames With Flamelet Models: A Comparison of Numerical Methods

Direct Numerical Simulation of Twin Swirling Flow Jets: Effect of Vortex-Vortex Interaction on Turbulence Modification

Prediction of momentum and scalar transport in turbulent swirling flows with an objective Reynolds-stress transport closure

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