Flow Dynamics and Mixing of a Transverse Jet in Crossflow—Part I: Steady Crossflow

Zhang, Liwei; Yang, Vigor

doi:10.1115/1.4035808

Cited by 16 publications

(3 citation statements)

References 51 publications

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“…The present work extends Part I of our study [1] on the flow dynamics and scalar mixing of a turbulent gaseous jet in steady crossflow, to investigate the intrinsic flow instabilities and the effect of external excitations in the crossflow.…”

Section: Introductionmentioning

confidence: 79%

Flow Dynamics and Mixing of a Transverse Jet in Crossflow—Part II: Oscillating Crossflow

Zhang

Yang

2017

Journal of Engineering for Gas Turbines and Power

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The present work extends Part I of our study to investigate the flow dynamics and scalar mixing of a turbulent gaseous jet in an oscillating crossflow. Attention is first given to intrinsic flow instabilities under a steady condition. Both power spectral density and proper orthogonal decomposition analyses are applied. For the case with a jet-to-crossflow velocity ratio of 4, the two most dynamic modes, corresponding to jet Strouhal numbers of around 0.1 and 0.7, are identified as being closely linked to the shear-layer vortices near the injector orifice and the vertical movement in the jet wake region, respectively. The effect of oscillation imposed externally in the upstream region of the crossflow is also examined systemically at a jet-to-crossflow velocity ratio of 4. A broad range of forcing frequencies and amplitudes are considered. Results reveal that the dominant structures observed in the case with a steady crossflow are suppressed by the harmonic excitations. Flapping–detaching motions, bearing the forcing frequencies and their subharmonics, become dominant as the forcing amplitude increases. The ensuing flow motions lead to the formation of a long, narrow jet plume and a relatively low mixing zone, which substantially alters the mixing efficiencies as compared to the case with a steady crossflow.

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Section: Introductionmentioning

confidence: 79%

Flow Dynamics and Mixing of a Transverse Jet in Crossflow—Part II: Oscillating Crossflow

Zhang

Yang

2017

Journal of Engineering for Gas Turbines and Power

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“…Immediately downstream of the injection slit, the kerosene flow separates and then reattaches to the wall, creating a stagnation point with a locus of positive divergence (node) at x = 90.6 mm; this structure is typical of a transverse jet in crossflow. 41,42 The swirl-induced centrifugal force and the expanding GOX stream push the kerosene toward the wall, as shown by the slightly tilted streamlines between x = 93 and 103. zone at the divergent point and a large recirculation zone in the downstream region. Secondary recirculation bubbles also appear.…”

Section: B Mean Flow Propertiesmentioning

confidence: 99%

“…To quantify mixing efficiency, the spatial mixing deficiency (SMD) 41 is calculated at several cross sections located between the GOX post end and the initial downstream region in the axial range of 88-145 mm. The SMD is a measure of spatial heterogeneity of flowfields and is calculated from the kerosene distribution over the cross sections of interest.…”

Section: Mixing Effectivenessmentioning

confidence: 99%

Supercritical fluid flow dynamics and mixing in gas-centered liquid-swirl coaxial injectors

Zhang

Wang

et al. 2018

Physics of Fluids

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Gas-centered, liquid-swirl coaxial injectors similar to those used in the main chambers of oxidizerrich staged-combustion engines are investigated computationally, in terms of supercritical fluid flow dynamics and mixing. Gaseous oxygen (GOX) is axially directed through a center post at a temperature of 687.7 K. Kerosene is tangentially introduced into the outer coaxial swirler at a temperature of 492.2 K. The mean chamber pressure of 253.0 bars substantially exceeds the thermodynamic critical pressures of oxygen and kerosene. The end of the GOX post is recessed from the entrance of the taper region, which is connected downstream to an open domain. A wide range of recess lengths (and correspondingly, fuel shielding collar lengths) is considered to determine the dependence of flow characteristics on this geometric parameter. Special attention is given to the regions downstream of the GOX post end and in the taper section, where primary mixing occurs. Instantaneous and time-averaged flow properties, as well as mixing effectiveness, are examined. Results indicate that the recess length plays a critical role in determining the flow evolution and mixing behaviors. In a fully recessed injector without fuel shielding, the initial kerosene/GOX interaction resembles a swirling transverse jet into a crossflow, and flow recirculation occurs near the kerosene injection slit and the head end. In other injectors with fuel shielding, the kerosene flow is predominantly axial before it enters the mixing zone; the coflow kerosene and GOX streams expand radially and recirculate in the wake of the GOX post. Flow unsteadiness arising from the fluid injection and mixing and vorticity production in the boundary layer of the GOX stream, along the wall of the fuel passage, and at the kerosene/GOX interface cause the development of salient vortical structures in the downstream flowfield. The geometric changes at the entrance of the taper region and at the injector exit further alter the flow dynamics, inducing multiple toroidal recirculation zones and secondary vortex structures.

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Three-dimensional features of the lateral thermal plume discharge in the deep cross-flow using dynamic adaptive mesh refinement

Khosravi

Javan

2022

Theor. Comput. Fluid Dyn.

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Flow Dynamics and Mixing of a Transverse Jet in Crossflow—Part I: Steady Crossflow

Cited by 16 publications

References 51 publications

Flow Dynamics and Mixing of a Transverse Jet in Crossflow—Part II: Oscillating Crossflow

Flow Dynamics and Mixing of a Transverse Jet in Crossflow—Part II: Oscillating Crossflow

Supercritical fluid flow dynamics and mixing in gas-centered liquid-swirl coaxial injectors

Three-dimensional features of the lateral thermal plume discharge in the deep cross-flow using dynamic adaptive mesh refinement

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