High-repetition-rate planar measurements in the wake of a reacting jet injected into a swirling vitiated crossflow

Panda, Pratikash; Roa, Mario; Slabaugh, Carson D.; Peltier, Scott; Carter, Campbell D.; Laster, W. R.; Lucht, Robert P.

doi:10.1016/j.combustflame.2015.10.001

Cited by 30 publications

(7 citation statements)

References 30 publications

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“…An increasing number of studies dealing with second stage combustion have been published recently. For instance, experimental works investigated the flame stabilization mechanism of non-premixed [3][4][5][6] and premixed [7,8] reactive jet in hot crossflow configurations. In their respective configurations, Sullivan et al [3] and Fleck et al [5] proposed autoignition as the dominant flame stabilization mechanism, while Micka and Driscoll [9], and Wagner et al [8] identified a mix of autoignition and flame propagation stabilizing the flame.…”

Section: Introductionmentioning

confidence: 99%

Combustion regimes in sequential combustors: Flame propagation and autoignition at elevated temperature and pressure

Schulz

Noiray

2019

Combustion and Flame

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This numerical study investigates the combustion modes in the second stage of a sequential combustor at atmospheric and high pressure. The sequential burner (SB) features a mixing section with fuel injection into a hot vitiated crossflow. Depending on the dominant combustion mode, a recirculation zone assists flame anchoring in the combustion chamber. The flame is located sufficiently downstream of the injector resulting in partially premixed conditions. First, combustion regime maps are obtained from 0-D and 1-D simulations showing the co-existence of three combustion modes: autoignition, flame propagation and flame propagation assisted by autoignition. These regime maps can be used to understand the combustion modes at play in turbulent sequential combustors, as shown with 3-D large eddy simulations (LES) with semi-detailed chemistry. In addition to the simulation of steady-state combustion at three different operating conditions, transient simulations are performed: (i) ignition of the combustor with autoignition as the dominant mode, (ii) ignition that is initiated by autoignition and that is followed by a transition to a propagation stabilized flame, and (iii) a transient change of the inlet temperature (decrease by 150 K) resulting into a change of the combustion regime. These results show the importance of the recirculation zone for the ignition and the anchoring of a propagating type flame. On the contrary, the autoignition flame stabilizes due to continuous self-ignition of the mixture and the recirculation zone does not play an important role for the flame anchoring.

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Section: Introductionmentioning

confidence: 99%

Combustion regimes in sequential combustors: Flame propagation and autoignition at elevated temperature and pressure

Schulz

Noiray

2019

Combustion and Flame

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“…On the other hand, the fluctuation velocities in the core decreased significantly with transition to distributed combustion condition (cases 3 & 4). To calculate turbulence Reynolds number, the integral length scale needs to be quantified in addition to the velocity fluctuation, which is shown in Fig 7. To obtain the integral length scale, the velocity fluctuations were analyzed using two-point correlations [35,36], where the integration of the correlation coefficient results in the integral length scale [37,38].…”

Section: Turbulence Characteristicsmentioning

confidence: 99%

Towards colorless distributed combustion regime

Khalil

Gupta

2017

Fuel

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Colorless distributed combustion (CDC) is a novel method for efficient and environmentally benign cleaner energy conversion of fossil and biofuels. CDC has been investigated in different configurations and geometries, with support to seek near zero emissions, uniform thermal field, energy savings, low pressure drop, and reduced combustion noise. In this paper, distributed combustion is investigated with focus on the flame-flowfield interaction and the different quantities that affect distributed combustion. The velocity field was obtained using Particle Image Velocimetry (PIV) with focus on mean and fluctuating quantities. The flowfield information helped differentiate between the impact of increasing Reynolds number (through air dilution) and the impact of lowering oxygen concentration (through modelled entrainment). The flowfield information was further processed to give the integral length scale at the flame boundaries. The integral length scale along with the fluctuating velocity is critical to determine turbulence Reynolds number and Damköhler number. Together these numbers identify the combustion regime at which the combustor is operating. This information clearly distinguishes between traditional swirl flames and distributed combustion and helps explain the significant benefits of distributed combustion as it operates in a well-stirred reactor regime. The results revealed that major controllers of the reaction regime are flame thickness and laminar flame speed; both are significantly impacted by lowering oxygen concentration through entrainment of hot reactive species from within the combustor, which is important in distributed combustion. Understanding the controlling factors of CDC is critical for the development and deployment of this novel method for near zero emissions from high intensity combustors and energy savings using fossil and of biofuels for sustainable energy conversion.

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“…In comparison with non-reacting JICF, the theoretical and experimental studies considering reacting JICF are limited. Through experimental observations in reacting JICF (Steinberg et al , 2013; Fairweather et al , 1992; Fleck et al , 2013a; Fleck et al , 2013b; Hasselbrink and Mungal, 2001a; Hasselbrink and Mungal, 2001b; Huang and Chang, 1994; Huang and Wang, 1999; Minamoto et al , 2015; Panda et al , 2016; Sullivan et al , 2014; Wagner et al , 2015; Wang et al , 2015; Zhang et al , 2016; Wagner et al , 2017a; Shang et al , 2017; Wagner et al , 2017b; Urson and Thomson, 2001), Sullivan et al (2014) have investigated the reacting jets in a high-temperature vitiated cross-flow for a wide range of momentum ratios (0.75 < J < 240). They have reported the effect of momentum ratios on the jet and flame trajectories, flame stabilization, flame width, flame lift-off and NO x emissions as the main features of time-averaged JICF flame.…”

Section: Introductionmentioning

confidence: 99%

LES/FMDF of turbulent reacting jet in cross-flow

Esmaeili

Afshari

2020

HFF

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Purpose This study aims to numerically investigate the flow features and mixing/combustion efficiencies in a turbulent reacting jet in cross-flow by a hybrid Eulerian-Lagrangian methodology. Design/methodology/approach A high-order hybrid solver is employed where, the velocity field is obtained by solving the Eulerian filtered compressible transport equations while the species are simulated by using the filtered mass density function (FMDF) method. Findings The main features of a reacting JICF flame are reproduced by the large-eddy simulation (LES)/FMDF method. The computed mean and root-mean-square values of velocity and mean temperature field are in good agreement with experimental data. Reacting JICF’s with different momentum ratios are considered. The jet penetrates deeper for higher momentum ratios. Mixing and combustion efficiency are improved by increasing the momentum ratio. Originality/value The authors investigate the flow and combustion characteristics in subsonic reacting JICFs for which very limited studies are reported in the literature.

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High-repetition-rate planar measurements in the wake of a reacting jet injected into a swirling vitiated crossflow

Cited by 30 publications

References 30 publications

Combustion regimes in sequential combustors: Flame propagation and autoignition at elevated temperature and pressure

Combustion regimes in sequential combustors: Flame propagation and autoignition at elevated temperature and pressure

Towards colorless distributed combustion regime

LES/FMDF of turbulent reacting jet in cross-flow

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