The effects of nozzle geometry and equivalence ratio on a premixed reacting jet in vitiated cross-flow

Pinchak, Matthew D.; Shaw, Vincent G.; Gutmark, Ephraim

doi:10.1016/j.combustflame.2017.12.018

Cited by 20 publications

(3 citation statements)

References 31 publications

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“…For instance, Weinzierl et al 5 used the LES method together with an NO x model to simulate a reacting JICF and predicted the NO x emission from an axial-staged combustion system. Pinchak et al 6 experimentally investigated the effects of jet equivalence ratio, momentum flux ratio, and jet geometry on the stability characteristics of a premixed ethylene-air jet injected into a vitiated crossflow. It is reported that under their experiment conditions, the flame stabilization process was controlled by flame propagation rather than by auto-ignition.…”

Section: Introductionmentioning

confidence: 99%

Combustion Mode and Mixing Characteristics of a Reacting Jet in Crossflow

et al. 2021

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Understanding of flame anchoring in a jet in crossflow (JICF) configuration is vital to the design of fuel injectors in combustion devices. The present study numerically investigates a hydrogen-rich jet injecting perpendicularly into hot vitiated crossflow using direct numerical simulation (DNS). The governing equations of low-Mach-number multicomponent reactive flows are solved, with a chemical mechanism for hydrogen-air flames containing 13 species and 35 reactions. The mixture-averaged multispecies transport model is employed to calculate the diffusion terms. Development of the reacting flow field and flame shape along the jet trajectory is depicted. The flame is found to be anchored around the jet exit and downstream only on the windward side. The heat release rate and chemical explosive mode analysis (CEMA) are used to identify combustion modes. Distinct from flames stabilized in nonvitiated crossflow, diffusion flame is dominant under the current conditions, though some premixed or partially premixed regions are found on the leeward side of the jet due to turbulent mixing. The near-field mixing of the reacting JICF is quantified by spatial unmixedness, in both two-dimensional (2D) and three-dimensional (3D) space.

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Section: Introductionmentioning

confidence: 99%

Combustion Mode and Mixing Characteristics of a Reacting Jet in Crossflow

et al. 2021

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“…The jet-in-crossflow is a canonical problem that spans a wide range of power, propulsion, and other applications [5]. The reacting jet in crossflow has become an increasingly popular topic of research over the last several years and the existing works in subsonic, reacting jet-in-crossflow literature can generally be divided in three ways: 1) heated air [6,7,8] or vitiated crossflow , 2) atmospheric [2,6,7,[15][16][17][18][19][20][21][22][23][24][25][26]29] or engine-relevant [8-14, 27, 28] conditions, and 3) fuel-only [6-8, 11-15, 27-29] or premixed fuel-air [2,[8][9][10][11][16][17][18][19][20][21][22][23][24][25] injection. Previous works that have developed optically accessible secondary combustion zones (SCZs) for steady-state, enginerelevant operation include efforts at Purdue University [8][9][10][11][12], Georgia Institute of Technology [13,14], and DLR-Stuttgar...…”

Section: Introductionmentioning

confidence: 99%

An optically accessible secondary combustion zone for the transverse injection of reacting jets into a high-speed, vitiated crossflow within a staged, gas turbine model combustor

Rodrigues¹,

McDonald²,

Busari³

et al. 2020

Meas. Sci. Technol.

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Advanced gas turbine combustion strategies, such as axially staging the fuel, are of great interest due to their potential to increase cycle efficiency while maintaining low levels of pollutants. In our previous work within a staged gas turbine model combustor, we used exhaust gas emissions measurements to demonstrate a significant NOX reduction by increasing the combustor exit Mach number, even at a constant residence time. In this paper, the development of an optically accessible secondary combustion zone (SCZ) to further study the injection of a reacting jet into a high-speed vitiated crossflow is described. Measurements were targeted for a nominally 1700 K vitiated crossflow, a premixed jet at an unburnt temperature of nominally 500 K, and a combustor pressure of 500 kPa. Key aspects of this design challenge include the high-speed and high temperature crossflow leading to relatively high convective heat flux at the inner surface of the windows and the necessary use of a narrow channel for the combustion gas. Emphasis is placed on the critical design features: a double-windowed design, an air-cooling scheme based on forced convection of air between the inner and outer windows, and intricate water-cooling circuits for the metal hardware. These design features have enabled long-duration, steady-state operation despite elevated pressure, high combustion gas temperatures, and high-speed reacting flows. The SCZ has survived operation at MW thermal powers over several hours of continuous operation and over a dozen test days to date; a set of windows retained good transparency without discoloration for typically 3–4 test days. Survivability of the windows through the air-cooling design has enabled us to study the reacting jet-in-crossflow at the desired high-speed conditions, without risking disturbing the physics with a window film-cooling flow. The capability to acquire useful measurements is illustrated using chemiluminescence imaging, pressure measurements, and emissions sampling.

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“…With smaller Kelvin-Helmholtz vortices, the temperature increase along the jet trajectory is quicker due to larger perimeter compared to the round nozzle, leading to closer and more frequent auto-ignition of the fuel-air mixture when the temperature reaches around 1600 K. We can also observe that the high temperature region appears at both windward and lee-side of the jet, probably due to the recirculation zone. The enhanced mixing effects of the slotted nozzle, revealed by the temperature field measurement, contribute to enhancement of flame stability [21].…”

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confidence: 97%

Single camera high repetition rate two-color formaldehyde planar laser-induced fluorescence thermometry with a wavelength-switching burst mode laser

Liu

Wang²,

Wang³

et al. 2021

Preprint

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We consider a two-color formaldehyde PLIF thermometry scheme using a wavelengthswitching injection seeding Nd:YAG laser at 355 nm. The 28183.5 cm −1 and 28184.5 cm −1 peaks of formaldehyde are used to measure low temperature combustion zone. Using a burst mode amplifier and a high speed camera, high-repetition rate (20 kHz) temperature field measurement is validated on a laminar coflow diffusion flame and demonstrated on a turbulent confined jet in hot crossflow flame.

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The effects of nozzle geometry and equivalence ratio on a premixed reacting jet in vitiated cross-flow

Cited by 20 publications

References 31 publications

Combustion Mode and Mixing Characteristics of a Reacting Jet in Crossflow

Combustion Mode and Mixing Characteristics of a Reacting Jet in Crossflow

An optically accessible secondary combustion zone for the transverse injection of reacting jets into a high-speed, vitiated crossflow within a staged, gas turbine model combustor

Single camera high repetition rate two-color formaldehyde planar laser-induced fluorescence thermometry with a wavelength-switching burst mode laser

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