Cavitation Bubble Cloud Break-Off Mechanisms at Micro-Channels

McGinn, P.; Pearce, D.; Hardalupas, Y.; Taylor, Alex; Vogiatzaki, Konstantina

doi:10.3390/fluids6060215

Cited by 5 publications

(4 citation statements)

References 37 publications

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“…To find the optimum mesh size for the given situation, a mesh independence study is carried out using Winklhofer's U-type geometry 45 by employing the fuel properties listed in Table I. The k − ω SST turbulence model with smooth wall conditions is used to extract the results for the mesh independence study.…”

Section: Mesh Independence Studymentioning

confidence: 99%

Investigation of nozzle geometry and wall roughness effects on diesel injector flow

Zainab,

Syed

2023

AIP Advances

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The flow and design of fuel injector nozzles have a considerable influence on the spray and combustion characteristics of a diesel engine. In-cylinder combustion, atomization, and primary breakdown are all highly influenced by the cavitation and turbulence in the fuel injector nozzle. In this paper, the effect of the nozzle geometry parameters, wall roughness parameters, and pressure difference on the swirl number, mass flow rate, turbulent kinetic energy, and vapor volume fraction is explored. U-type nozzle hole geometry, a well-known benchmark for the injector nozzle flow, is used to evaluate mesh independence and model validation. Large-eddy simulations are performed to provide a precise presentation of the flow structures and turbulent eddies inside the nozzle. Multiphase flow is studied using the mixture model, whereas cavitation is studied using the Schnerr–Sauer model based on the Rayleigh–Plesset equation. We find that the wall roughness parameters have an exciting impact on the discharge coefficient, swirl number, and vapor volume fraction. Due to the non-monotonic dependence of nozzle flow characteristics on the pressure difference and the wall roughness parameters, we can always find such values of these input parameters that render optimal nozzle flow characteristics. In this way, these parameters provide good control of spray formation and consequently on the quality and rate of combustion in the diesel engine.

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Section: Mesh Independence Studymentioning

confidence: 99%

Investigation of nozzle geometry and wall roughness effects on diesel injector flow

Zainab,

Syed

2023

AIP Advances

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“…When the formed vapor structures collapse violently, the surface energy is conserved and influences the evolution of the surrounding surfaces. 3,6 First, the conserved energy further augments the collapse of other vapor cavities from the shock that is caused within the structure which is due to the bubbly mixture leading to a reduced speed of sound. 6,7 Second, this energy is also transported downstream the nozzle exit where it influences the surface breakup of the atomization process.…”

Section: Introductionmentioning

confidence: 99%

“…3,6 First, the conserved energy further augments the collapse of other vapor cavities from the shock that is caused within the structure which is due to the bubbly mixture leading to a reduced speed of sound. 6,7 Second, this energy is also transported downstream the nozzle exit where it influences the surface breakup of the atomization process. 3 Third, the energy that is conserved from the violent collapse also causes material erosion and inevitable failure of the injector.…”

Section: Introductionmentioning

confidence: 99%

Three-component volume of fluid method coupling with interface compression method and Eulerian–Lagrangian spray atomization surface density model for prediction of cavitating sprays

McGinn,

Tretola,

Vogiatzaki

2024

Physics of Fluids

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In this work, a new three phase cavitation model with Eulerian–Lagrangian Spray Atomization (ELSA) and Interface Capturing Method (ICM) coupling is presented to allow for, in a unified approach, physical insight of the surface evolution of cavitating sprays at the Sub-Grid Scale (SGS). Phase change is accounted for in the framework via mass transfer across a liquid and corresponding vapor phase. The surface density model was validated against direct numerical simulation data of an atomizing jet with a systematic variation of mesh resolutions. The sensitivity of the adjustable parameters such as the critical Weber number was also demonstrated. Then, experimental comparisons were made with a more realistic orthogonal spray geometry within a cavitating and turbulent non-cavitating system. These comparisons include both large scale visualizations and small scale SGS quantities such as the Sauter mean diameter. To our knowledge, this is the first study that presents the performance of a three phase cavitating framework with SGS ELSA-ICM coupling.

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“…The cavitation in the cavitation ring grew rapidly near the nozzle and decreased gradually. Paul McGinn et al [20] studied the role of the pressure wave in the flow development and found that the dynamics of the pressure wave determined the dynamic characteristics of the bubble cloud under the condition of "choking". Ruolong Ma et al [21] proposed a model that provides a prediction of the resonator pressure fluctuations based on the thickness of the approach boundary layer, the free stream speed and the acoustic properties of the resonator.…”

Section: Introductionmentioning

confidence: 99%

Effect of Nozzle Outlet Shape on Cavitation Behavior of Submerged High-Pressure Jet

et al. 2021

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A submerged high-pressure water jet is usually accompanied by severe cavitation phenomenon. An organ pipe nozzle can greatly improve the cavitation performance of the jet, making use of the self-excited oscillation of the flow. In order to study the effect of organ pipe nozzles of different nozzle outlet shapes on cavitation behavior of submerged high-pressure jet, in this paper we build a high-pressure cavitation jet experiment system and carried out a high-speed photography experiment to study cavitation cloud characteristics of a high-pressure submerged jet. Two organ pipe nozzles with and without a whistle were compared. The dynamic characteristics of the cavitation cloud was extracted through the POD method, it was found that the result effectively reflect the dynamic characteristics of the cavitation jet. The reconstruction coefficients of mode-1 obtained by the POD can better reflect the periodic time-frequency characteristics of cavitation development. The effect of the nozzle outlet shape on the cavitation behavior of organ pipe nozzle was analyzed based on unsteady numerical simulation, and it was found that the jet generated by the nozzle with a divergent whistle had a larger vorticity in the shear layer near the outlet. Further, stronger small-scale vortex and much severe cavitation occurred from the nozzle with a divergent whistle.

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Cavitation Bubble Cloud Break-Off Mechanisms at Micro-Channels

Cited by 5 publications

References 37 publications

Investigation of nozzle geometry and wall roughness effects on diesel injector flow

Investigation of nozzle geometry and wall roughness effects on diesel injector flow

Three-component volume of fluid method coupling with interface compression method and Eulerian–Lagrangian spray atomization surface density model for prediction of cavitating sprays

Effect of Nozzle Outlet Shape on Cavitation Behavior of Submerged High-Pressure Jet

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