Experimental and numerical investigation of pressure swirl atomizers

Sümer, Bülent
In this study, unsteady flows inside a pressure swirl atomizer are investigated using experimental and numerical techniques. High Speed Shadowgraphy Technique is used in order to visualize the flow structures inside the atomizer and the resulting spray at high temporal and spatial resolutions. The images of the air core inside the pressure swirl atomizer and the resulting spray formations are captured at four di erent water flow rates. Then, the time variation of the air core diameter at di erent axial locations of the atomizer is found using the image processing tool developed. The corresponding mean spray cone angles are similarly obtained. The analysis reveals the unsteady features of the air core and the macroscopic properties of the spray. Microscopic properties of the spray are determined using a two component Phase Doppler Particle Analyzer. Sauter mean diameter distributions of the resulting water droplets and the velocity distributions for two di erent droplet size classes are obtained as a function of flow rate through the atomizer. Unsteady, two-phase flow fields within the pressure swirl atomizer are computed using a computational fluid dynamics tool based on the volume of fluid method. Two dimensional axisymmetric swirl and three dimensional numerical simulations are performed to analyze the unsteady flows inside the atomizer. The vortex structures inside the pressure swirl atomizer and the axial variation of core diameter are investigated. As a result of the experimental and numerical studies, it is found that the air core diameter and spray cone angle are not much sensitive to the flow rate. The experimental and numerical studies show that, the low frequency oscillations observed in the velocity field are associated with the dynamics of the vortical structures within the water region, while the high frequency oscillations are associated with the dynamics of the vortical structures at the head end of the air core.


Investigation of the effect of geometrical parameters of pressure swirl atomizer on the hollow cone spray
Tokgöz, Tolga; Ulaş, Abdullah; Department of Mechanical Engineering (2019)
In this study, effects of geometrical parameters of pressure swirl atomizer on the hollow cone spray are investigated experimentally, and physical phenomenon inside the pressure swirl atomizer is investigated numerically. In the experimental studies, hollow cone spray properties are examined macroscopically and microscopically. Macroscopic spray properties are studied by a visual technique called high-speed shadowgraphy. The hollow cone spray images are captured for different geometrical configurations of t...
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Ozdemir, Esra; Hacaloğlu, Jale (2018-01-01)
In this study, electrospun fibers of melt blended poly(lactic acid) and poly(ethylene glycol), (PLA)-PEG blends involving 10, 15 and 20 wt% PEG and their corresponding composites with organically modified montmorillonite, Cloisite 30B were prepared and characterized by x-ray diffraction, differential scanning calorimetry, thermogravimetry and direct pyrolysis mass spectrometry techniques. The narrower fiber diameters observed for the PLA-PEG fibers involving organoclay compared to the corresponding neat fib...
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Gücüyener, I. Hakki; Kök, Mustafa Verşan; Batmaz, Taner (2002-05-01)
This paper demonstrates the order of influence of end effects on the application of a theory to determine and correct the end effects in Couette coaxial cylinder rotational viscometers, which are commonly used for the rheological evaluation of drilling fluids. It is found that higher shear stresses are measured due to end effects and, consequently, this error bearing shear stress-shear rate data leads to unreliable predictions of the rheological parameters. Evaluation of the shear stress-shear rate data obt...
Incompressible flow simulations using least squares spectral element method on adaptively refined triangular grids
Akdağ, Osman; Sert, Cüneyt; Department of Mechanical Engineering (2012)
The main purpose of this study is to develop a flow solver that employs triangular grids to solve two-dimensional, viscous, laminar, steady, incompressible flows. The flow solver is based on Least Squares Spectral Element Method (LSSEM). It has p-type adaptive mesh refinement/coarsening capability and supports p-type nonconforming element interfaces. To validate the developed flow solver several benchmark problems are studied and successful results are obtained. The performances of two different triangular ...
Mathematical Modeling of Turbulent Flows of Newtonian Fluids in a Concentric Annulus with Pipe Rotation
SORGUN, MEHMET; Aydın, İsmail; ÖZBAYOĞLU, Evren; SCHUBERT, J J (2012-03-01)
In this study, a mathematical model is proposed to predict flow characteristics of Newtonian fluids inside a concentric horizontal annulus. A numerical solution, including pipe rotation, is developed for calculating frictional head losses in concentric annuli for turbulent flow. Navier-Stokes equations are numerically solved using the finite differences technique to obtain the velocity field. Experiments with water are performed in a concentric annulus with and without pipe rotation. Average fluid velocitie...
Citation Formats
B. Sümer, “Experimental and numerical investigation of pressure swirl atomizers,” Ph.D. - Doctoral Program, Middle East Technical University, 2014.