Experimental and numerical investigation of pressure swirl atomizers

Download
2014
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.

Suggestions

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...
Design and analysis of a vertical axis water turbine for river applications using computational fluid dynamics
Demircan, Eren; Aksel, Mehmet Haluk; Pınarcıoğlu, Mehmet Melih; Department of Mechanical Engineering (2014)
The main purpose of this study is to design a Darrieus rotor type vertical axis water turbine using Computational Fluid Dynamics (CFD) in order to be used in river currents. The CFD modeling is based on two dimensional numerical solution of the rotor motion using commercial Unsteady Reynolds Averaged Navier-Stokes solvers, Ansys Fluent and CFX. To validate the two dimensional numerical solution, an experimental Darrieus rotor type water turbine from literature is studied and performance of several turbulenc...
Vortex generator design for subsonic inlets
Nasuhbeyoğlu, Batuhan; Albayrak, Kahraman; Department of Mechanical Engineering (2014)
In this thesis, numerical investigation of the benefits of vortex generators control on the performance of S-shaped inlets has been performed. This study is divided into two main parts. In the first part, a diffusive S-shaped inlet is examined and the numerical analyses results are compared with the experimental results. Three-dimensional Navier-Stokes equations are solved and three different turbulence models which are Realizable k-ε, Standard k-ω, and Spalart-Allmaras methods are used. Distortion coeffici...
Thermal degradation of Polylactide/Poly(ethylene glycol) fibers and composite fibers involving organoclay
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...
Prediction of Non-Darcy flow effects on fluid flow through porous media based on field data
Alp, Ersen; Akın, Serhat; Department of Chemical Engineering (2012)
The objective of this dissertation is to investigate the non-Darcy flow effects on field base data by considering gas viscosity, gas deviation factor and gas density as variables. To achieve it, different correlations from the literature and field data have been combined to Sawyer-Brown Method, thus a contribution has been achieved. Production history of selected gas field has been implemented to a numerical simulator. To find out non-Darcy effects quantitatively, Darcy flow conditions have also been run in...
Citation Formats
B. Sümer, “Experimental and numerical investigation of pressure swirl atomizers,” Ph.D. - Doctoral Program, Middle East Technical University, 2014.