Comparison of numerical models for prediction of pressure-swirl atomizer internal flow

This paper compares 2D axisymmetric and 3D numerical models used to predict the internal flow of a pressure-swirl atomizer using a commercial software Ansys Fluent 18.1. The computed results are compared with experimental data in terms of spray cone angle (SCA), discharge coefficient (CD), internal air-core dimensions and swirl velocity profile. The swirl velocity was experimentally studied using a Laser Doppler Anemometry in a scaled transparent model of the atomizer. The internal air-core was visualized at high temporal and spatial resolution by a high-speed camera with backlit illumination. The internal flow was numerically treated as transient two-phase flow. The gas-liquid interface was captured with Volume of Fluid scheme. The numerical solver used both laminar and turbulent approach. Turbulence was modelled using k-ε, k-ω, Reynolds Stress model (RSM) and coarse Large Eddy Simulation (LES). The laminar solver was capable to predict all the parameters with an error less than 5% compared with the experimental results in both 2D and 3D simulation. However, it overpredicted the velocity of the discharged liquid sheet. The LES model performed similarly to the laminar solver, but the liquid sheet velocity was 10% lower. The two-equation models k-ε and k-ω overpredicted the turbulence viscosity and the internal air-core was not predicted.

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A Numerical Approach for the Simulation of Internal Nozzle Flow in a Pressure Swirl Atomizer Using Different Turbulent Models and Towards an Effective Inlet Weber Number

Volume 7A: Fluids Engineering Systems and Technologies ◽

10.1115/imece2013-65627 ◽

2013 ◽

Author(s):

Ahmadreza Abbasi Baharanchi ◽

Seckin Gokaltun ◽

Shahla Eshraghi

Keyword(s):

Weber Number ◽

Computational Cost ◽

Internal Flow ◽

Numerical Approach ◽

Reynolds Stress Model ◽

Multiphase Model ◽

Vof Model ◽

Swirl Atomizer ◽

Pressure Swirl ◽

Pressure Swirl Atomizer

VOF Multiphase model is used to simulate the flow inside a pressure-swirl-atomizer. The capability of the Reynolds Stress Model and variants of the K-ε and K-ω models in modeling of turbulence has been investigated in the commercial computational fluid dynamics (CFD) software FLUENT 6.3. The Implicit scheme available in the volume-of-fluid (VOF) model is used to calculate the interface representation between phases. The atomization characteristics have been investigated as well as the influence of the inlet swirl strength of the internal flow. The numerical results have been successfully validated against experimental data available for the computed parameters. The performance of the RNG K-ε model was found to be satisfactory in reducing the computational cost and introducing an effective Weber number for the flow simulated in this study.

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A Description of the Pressure Swirl Atomizer Internal Flow

Volume 1: Fora, Parts A and B ◽

10.1115/fedsm2002-31017 ◽

2002 ◽

Cited By ~ 4

Author(s):

D. Donjat ◽

J. L. Estivalezes ◽

M. Michau

Keyword(s):

Numerical Simulation ◽

Large Scale ◽

Swirling Flow ◽

Internal Flow ◽

Liquid Interface ◽

2D Numerical Simulation ◽

Swirl Atomizer ◽

Pressure Swirl ◽

Pressure Swirl Atomizer ◽

Exit Orifice

The context of the present work is an investigation of the influence of geometry on the structure of the pressure swirl atomizer internal flow. Vizualisations and measurements techniques (LDA and PIV) are used on a large-scale pressure swirl atomizer. The behaviour of inlets jets and the development of the swirling flow are studied. Measurements of the aircore/liquid interface instabilities revealed the fundamental influence of inlet slots and exit orifice. Finally, a comparison between experimental results and a 2D numerical simulation is presented.

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Nonlinear Breakup Model for a Liquid Sheet Emanating From a Pressure-Swirl Atomizer

Journal of Engineering for Gas Turbines and Power ◽

10.1115/1.2747263 ◽

2007 ◽

Vol 129 (4) ◽

pp. 945-953 ◽

Cited By ~ 17

Author(s):

Ashraf A. Ibrahim ◽

Milind A. Jog

Keyword(s):

Flow Field ◽

Ambient Pressure ◽

Internal Flow ◽

Liquid Sheet ◽

Nonlinear Instability ◽

Breakup Length ◽

Sheet Breakup ◽

Swirl Atomizer ◽

Pressure Swirl ◽

Pressure Swirl Atomizer

Predictions of breakup length of a liquid sheet emanating from a pressure-swirl (simplex) fuel atomizer have been carried out by computationally modeling the two-phase flow in the atomizer coupled with a nonlinear analysis of instability of the liquid sheet. The volume-of-fluid (VOF) method has been employed to study the flow field inside the pressure-swirl atomizer. A nonlinear instability model has been developed using a perturbation expansion technique with the initial amplitude of the disturbance as the perturbation parameter to determine the sheet instability and breakup. The results for sheet thickness and velocities from the internal flow solutions are used as input in the nonlinear instability model. Computational results for internal flow are validated by comparing film thickness at exit, spray angle, and discharge coefficient with available experimental data. The predictions of breakup length show a good agreement with semiempirical correlations and available experimental measurements. The effect of elevated ambient pressure on the atomizer internal flow field and sheet breakup is investigated. A decrease in air core diameter is obtained at higher ambient pressure due to increased liquid-air momentum transport. Shorter breakup lengths are obtained at elevated air pressure. The coupled internal flow simulation and sheet instability analysis provides a comprehensive approach to modeling sheet breakup from a pressure-swirl atomizer.

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Internal flow characteristics in scaled pressure-swirl atomizer

EPJ Web of Conferences ◽

10.1051/epjconf/201818002059 ◽

2018 ◽

Vol 180 ◽

pp. 02059 ◽

Cited By ~ 1

Author(s):

Milan Malý ◽

Marcel Sapík ◽

Jan Jedelský ◽

Lada Janáčková ◽

Miroslav Jícha ◽

...

Keyword(s):

High Speed ◽

Laser Doppler Anemometry ◽

Flow Characteristics ◽

Internal Flow ◽

Liquid Sheet ◽

Wide Range ◽

Swirl Atomizer ◽

Pressure Swirl ◽

Pressure Swirl Atomizer ◽

Working Liquid

Pressure-swirl atomizers are used in a wide range of industrial applications, e.g.: combustion, cooling, painting, food processing etc. Their spray characteristics are closely linked to the internal flow which predetermines the parameters of the liquid sheet formed at the discharge orifice. To achieve a better understanding of the spray formation process, the internal flow was characterised using Laser Doppler Anemometry (LDA) and high-speed imaging in a transparent model made of cast PMMA (Poly(methyl methacrylate)). The design of the transparent atomizer was derived from a pressure-swirl atomizer as used in a small gas turbine. Due to the small dimensions, it was manufactured in a scale of 10:1. It has modular concept and consists of three parts which were ground, polished and bolted together. The original kerosene-type jet A-1 fuel had to be replaced due to the necessity of a refractive index match. The new working liquid should also be colourless, non-aggressive to the PMMA and have the appropriate viscosity to achieve the same Reynolds number as in the original atomizer. Several liquids were chosen and tested to satisfy these requirements. P-Cymene was chosen as the suitable working liquid. The internal flow characteristics were consequently examined by LDA and high-speed camera using p-Cymene and Kerosene-type jet A-1 in comparative manner.

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Numerical Analysis of Pressure Swirl Atomizer

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.798.190 ◽

2015 ◽

Vol 798 ◽

pp. 190-194

Author(s):

Mehmet Kahraman ◽

Guven Komurgoz ◽

Ibrahim Ozkol

Keyword(s):

Cone Angle ◽

Computational Cost ◽

Internal Flow ◽

Combustion Engines ◽

Spray Cone Angle ◽

Spray Cone ◽

Swirl Atomizer ◽

Pressure Swirl ◽

Pressure Swirl Atomizer

Atomization quality of liquids has a great importance on the performance of combustion engines. In this study the internal flow phenome of pressure swirl atomizer is investigated by using numerical method. The design of swirl atomizer is performed based on the requested atomizer characteristics which are sauter mean diamer (SMD), spray cone angle and break up length. Prediction and understanding of liquid film dynamics in the atomizer inside are the fundamental ways to explore atomizer performance. The purpose of this study is to estimate the air core size and film thickness in pressure swirl atomizer by setting single phase numeric computations. This article concludes that the CFD validated swirl atomizer design can be achieved with the lower computational cost using stream function methodology.

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A Numerical Study of the Internal Flow in a Pressure Swirl Atomizer

Volume 4A: Combustion, Fuels and Emissions ◽

10.1115/gt2017-64149 ◽

2017 ◽

Author(s):

Weijia Qian ◽

Xin Hui ◽

Chi Zhang ◽

Quanhong Xu ◽

Yuzhen Lin ◽

...

Keyword(s):

Internal Flow ◽

Diameter Ratio ◽

Geometric Parameters ◽

Swirl Chamber ◽

Discharge Parameters ◽

Swirl Atomizer ◽

Pressure Swirl ◽

Pressure Swirl Atomizer ◽

Exit Orifice ◽

Length To Diameter Ratio

The internal flow and discharge parameters of a pressure swirl atomizer (PSA) are numerically investigated using a coupled Level-Set (LS)/Volume-of-Fluid (VOF) solver that combines the advantages of LS and algebraic VOF methods by maintaining the mass conservation and the interface sharpness simultaneously. Internal flow velocity profile and discharge parameters including discharge coefficient, film thickness, and spray cone angle are compared between simulation results and the experimental data that are available in the literature. A parametrical study is also performed to investigate the effects of the key geometric parameters of the PSA configuration on the discharge parameters. The geometric parameters studied are the length to diameter ratio of the swirl chamber, the length to diameter ratio of the exit orifice, the swirl chamber diameter to exit orifice diameter ratio, and the swirl chamber convergence angle.

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