Characterization of the Behavior of Confined Laminar Round Jets

Landfried, D. Tyler; Jana, Anirban; Kimber, Mark

doi:10.1115/1.4028834

Cited by 3 publications

(4 citation statements)

References 9 publications

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“…Hence, assuming a point momentum source, the round jet analogy (Schlichting 1933; Tyler Landfried et al. 2015) is applied, which suggests that the jet half-width is proportional to and it also increases linearly with the axial distance (). This is mathematically expressed as follows: where is the initial jet width at the rear stagnation point, is the jet width at an axial distance of from the rear stagnation point and is the Reynolds number of the relative flow based on .…”

Section: Resultsmentioning

confidence: 99%

“…A fully enveloped buoyant diffusion flame was formed in the initial phase, which transitioned into a wake flame due to forward extinction. The wake flame is reported to be bluff-body stabilized in the droplet wake (see figure 1b), and the round jet analogy (Schlichting 1933;Tyler Landfried, Jana & Kimber. 2015) was used for theoretical modelling.…”

Section: Introductionmentioning

confidence: 95%

“…This open-brush-shaped flame closely resembles a laminar premixed jet flame (Pandey et al 2020), exhibiting an open tip with a premixed structure due to intense mixing in the recirculation zone. Hence, assuming a point momentum source, the round jet analogy (Schlichting 1933;Tyler Landfried et al 2015) is applied, which suggests that the jet half-width is proportional to Re −1 and it also increases linearly with the axial distance (x). This is mathematically expressed as follows:…”

Section: Bluff-body-stabilized Wake Flamementioning

confidence: 99%

“…The wake flame is reported to be bluff-body stabilized in the droplet wake (see figure 1 b ), and the round jet analogy (Schlichting 1933; Tyler Landfried, Jana & Kimber. 2015) was used for theoretical modelling. The suppression of the BVK instabilities at high Re was observed due to the high temperatures generated by the flame in the wake region.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Insights into the flame transitions and flame stabilization mechanisms in a freely falling burning droplet encountering a co-flow

Vadlamudi,

Aravind,

Basu

2023

J. Fluid Mech.

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The present study investigates the flame dynamics of a contactless burning fuel droplet under free fall subjected to a co-flow. The dynamic external relative flow established due to co-flow and droplet acceleration results in a series of droplet flame transitions. Different flame structures were observed, including a wake flame, reversed wake flame and enveloped flame. Following ignition, the droplet is allowed to fall through the central tube of a co-flow arrangement, and, at its exit, the droplet flame encounters the co-flow. The wake flame, which was established based on the droplet's instantaneous velocity of descent, encounters the abrupt relative velocity jump due to the co-flow. This causes the droplet flame to go through various transitions as it approaches equilibrium with the surrounding flow. Once it equilibrates, the droplet flame evolves in response to the instantaneous relative flow velocity. The droplet flame evolves by altering both its shape and the stabilization mechanism. Two stabilization mechanisms were identified for the droplet wake flame: edge-flame stabilization and bluff-body stabilization. The stabilization mechanism for different flame structures and the transition events have been theoretically analysed, and the relation between flame shape evolution and flow velocity has been determined based on the flow-field characteristics at the corresponding Re (Reynolds number) range. Furthermore, these correlations are employed in a mathematical formulation based on the spring–mass analogy, which predicts the droplet flame evolution after encountering the co-flow, including all the transition events.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 95%

Section: Bluff-body-stabilized Wake Flamementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Insights into the flame transitions and flame stabilization mechanisms in a freely falling burning droplet encountering a co-flow

Vadlamudi,

Aravind,

Basu

2023

J. Fluid Mech.

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The Flow and Decay Behavior of a Submerged Shear-Thinning Jet With Yield Stress

Hammad

2016

Journal of Fluids Engineering

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The flow and decay characteristics of submerged jets of shear-thinning fluids with yield stress are studied. Numerical solutions to the governing mass and momentum conservation equations, along with the Herschel–Bulkley rheological model, are obtained using a finite-difference scheme. A parametric study is implemented to investigate the influence of flow inertia and rheology over the following range of parameters: Reynolds number, 50 ≤ Re ≤ 200; yield number, 0 ≤ Y ≤ 1; and shear-thinning index, 0.6 ≤ n ≤ 1. A large recirculation region exists for Newtonian and shear-thinning non-Newtonian jets. However, the extent and strength of the recirculation region substantially diminish with the yield number and, to a lesser extent, when the shear-thinning index is reduced from 1 to 0.6. Increasing the yield number beyond a critical value eliminates flow recirculation. The centerline velocity and momentum decay of shear-thinning jets with yield stress, in general, increase with the yield number. Velocity- and momentum-based depths of penetration, DPU, and DPM, respectively, are introduced and presented. DPU and DPM are the downstream locations corresponding to 90% decay in the initial centerline velocity and jet momentum, respectively. A substantial decrease in DPU and DPM is observed when the shear-thinning index is reduced from 1 to 0.6 for Y = 0. The presence of yield stress significantly reduces both DPU and DPM of submerged jets. The impact of shear-thinning on the decay characteristics of the jet is more pronounced at low yield numbers.

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Inflow Conditions and the Flow Behavior of Submerged Annular Viscoplastic Non-Newtonian Jets

Hammad

2024

Journal of Fluids Engineering

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Submerged annular viscoplastic jet flows were studied numerically within the steady laminar flow regime. The impacts of inner-to-outer annular nozzle diameter ratio, and yield number, for uniform and fully-developed inflow conditions, were investigated. The extent of the outer recirculation region and recirculation intensities of both the central and outer regions were found to substantially diminish with the yield number, resulting in the elimination of recirculation throughout the whole flow field at high yield numbers. The axial penetration of the jet decreases with both the yield number and the annular diameter ratio. The impact of inflow conditions on the flow structure and decay characteristics of the jet is more pronounced at low yield numbers.

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Characterization of the Behavior of Confined Laminar Round Jets

Cited by 3 publications

References 9 publications

Insights into the flame transitions and flame stabilization mechanisms in a freely falling burning droplet encountering a co-flow

Insights into the flame transitions and flame stabilization mechanisms in a freely falling burning droplet encountering a co-flow

The Flow and Decay Behavior of a Submerged Shear-Thinning Jet With Yield Stress

Inflow Conditions and the Flow Behavior of Submerged Annular Viscoplastic Non-Newtonian Jets

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