Download or read book Experimental and Computational Study on Liquid Atomization by Slinger Injector written by Carmen Sescu and published by . This book was released on 2011 with total page 219 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this research work the flow characteristics of a type of rotary atomizer, referred to as slinger injector, were experimentally and numerically investigated at relatively low rotational speeds. Although slinger injectors provide a good level of atomization at high rotational speeds where they are intended to operate (30,000 rpm or higher), a critical aspect in small gas turbines is related to the start-up phase, which typically takes place at speeds around 10,000 rpm. The quality of atomization is very important, especially at these low speeds where smaller mean fuel droplet diameters are desirable. The current work focused on the study of atomization provided by slinger injectors at rotational speed related pertinent to the start-up phase (up to 15,000 rpm). An optical measurement system was implemented to investigate the liquid atomization provided by the slinger injector. The qualitative behavior of fuel emerging from the slinger was evaluated to determine whether a satisfactory atomization was provided within a distance compatible with the size of a small gas turbine engine combustion chamber. The size of the droplets was measured using the Global Sizing Velocimetry (GSV) system. Visualization of the primary liquid breakup process, determination of breakup lengths, and measurement of droplet size were performed by varying rotational speed, liquid flow rate, injector hole shape, size and orientation, and number of holes. Photographs of the liquid breakup, various mean and representative diameters, droplet size histograms and cumulative volume distribution are presented. The findings of this thesis show that droplet size decrease with an increase in rotational speed, as expected. Moreover, hole diameter, hole shape and flow rates affect the slinger atomization. For a given flow rate and a given rotational speed, the experimental data show that the droplet sizes decrease by increasing the hole diameter. The droplets increase in size when the flow rates is increased for a given hole size. The atomization was found to be characteristically different for a slit compared to a circular hole injector. However, the orientation of the emerging jet relative to the axis of rotation insignificantly influenced the slinger atomization for the cases studied. A correlation equation was obtained for a slinger with circular hole, estimating the Sauter mean diameter as a function of the rotational speed of the slinger, the hole diameter, the liquid flow rate and the liquid properties. Two-dimensional and three-dimensional numerical simulations of the internal flow and the external near-field flow for a slinger atomizer were conducted. The simulations were carried out using the commercial Computational Fluid Dynamics code FLUENT, wherein the Volume of Fluid model was used to track the interface between the two phases. A User Defined Function was developed to take into account the centrifugal and Coriolis forces needed for FLUENT computations. The numerical simulations focused on the study of formation of the liquid film along the channel injector wall, and on the upstream characteristics of the liquid jet near the exit of the atomizer. The numerical simulations were in qualitative agreement with the experiment, showing that an annular jet exiting from the channel collapses and the liquid breaks up into droplets a short distance from the exist. The results show that the Volume of Fluid model is appropriate for developing simulation models of the working of a slinger atomizer.
Download or read book Computational and Experimental Study of Geometry Modifications Inside a Flow blurring Injector written by Nathan James Vardaman and published by . This book was released on 2018 with total page 274 pages. Available in PDF, EPUB and Kindle. Book excerpt: Liquid fuel atomization is widely used for combustion in many applications. With the strong emphasis on emissions regulations coupled with the ever increasing drive to improve energy efficiency, all aspects of combustion are being thoroughly researched. One key way to achieve the above goals is further improvement in the liquid fuel atomization process. Better atomization improves mixing of fuel and air, thus results in lower emissions, whereas improved liquid fuel injector designs can improve energy efficiency. The flow-blurring (FB) atomization technique, developed recently and investigated at the University of Alabama, has shown promise in both these areas. Previous research has shown that the FB injector produces smaller droplets and a more desirable droplet distribution than the commercial air-blast injector. In addition, the FB injector is able to successfully atomize a wider range of fuels, and it is much less susceptible to the change in surface tension or viscosity of the liquid fuel. In this study, a computational fluid dynamics (CFD) model is created to mimic the mixing of the fuel and air inside the injector, and thus, understand the underlying physics of the FB atomization process. The 2D model is assumed to be asymmetric and incompressible, and it uses the mixture model for the two-phase flow. A transient solution is found and analyzed revealing a recirculation zone, due to a stagnation point near the exit, is formed within the fuel tube of the injector. The recirculation zone is responsible for the mixing of fuel and air and the formation of bubbles. Prior experimental research conclusions are compared with the model as various operating conditions are implored for verification of the models accuracy. Finally, the model is utilized by simulating and studying the effect of geometric modifications within the wall gap of the FB injector. An inner-slant wall gap provides promising results compared to the original geometry. The geometry modifications are then implemented in an actual injector tested in an atmospheric burner. Emissions measurements, thermal imaging of the combustor surface, and OH* chemiluminescence imaging of the flame are used to first verify proper operation of the combustor and then to characterize the flame structure. Several operating conditions are altered and the influence of these changes is studied. OH* chemiluminescence images reveal the flame is stable and a better distribution of OH* signals represents improved atomization. Finally, the geometric modifications to the injector are tested to determine the performance improvements with respect to the baseline design. Experimental results of the different geometries indicate the injector with inner-slant seems to improve the atomization process. The inner-slant injector has lower emissions for a range of ALR values and a lower pressure drop though the injector compared to the original geometry.
Download or read book Liquid Atomization written by L.P. Bayvel and published by Routledge. This book was released on 2019-01-22 with total page 488 pages. Available in PDF, EPUB and Kindle. Book excerpt: Covering the basics of liquid atomization, this book familiarizes readers with the physical processes of liquid atomization, the main types of atomizers and their design, measurements of spray characteristics, experimental investigations of atomizers, and application of atomizers. It demonstrates how to calculate and design atomizers and how to mea
Download or read book Experimental and Computational Study of an Ultrasonic Atomizer written by Phattharawadee Phanphanit and published by . This book was released on 2011 with total page 273 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Experimental and Computational Study of an Ultrasonic Atomizer written by Phattharawadee Phanphanit and published by . This book was released on 2011 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Theory and Practice of Swirl Atomizers written by Yuriy I Khavkin and published by CRC Press. This book was released on 2003-10-28 with total page 490 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this book, prominent Russian scientist Yuriy I. Khavkin shows that the droplet sizes in swirl atomizers depend only on the specific energy of the liquid drops and on viscosity. The new theory based only on two parameters is shown to be far simpler and in better agreement with experimental data than any previous presentations. The following topics are included in the book: · The solution of the Navier-Stokes equation for a liquid rotating flow · Atomizers for gas turbine combustion chambers · Atomizers for high capacity steam boilers · Atomizers for liquid-propellant rocket engines · Quality of liquid atomization by non-swirl atomizers · A unique table of experimental data of 232 atomizers, enables the reader to find an atomizer with the flow rate from 5 kg/h to 15,000 kg/h Readers will also learn: · To create an atomizer with the given mean droplet size · To create an atomizer with the given droplet size distribution · To create an atomizer with the given limits of flow rate control. The book is intended for the design engineer, as well as the theoretical scientist.
Download or read book Atomization and Sprays written by and published by . This book was released on 2009 with total page 456 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Atomization and Sprays written by Arthur Lefebvre and published by CRC Press. This book was released on 1988-12-01 with total page 434 pages. Available in PDF, EPUB and Kindle. Book excerpt: Atomization and Sprays examines the atomization of liquids and characteristics of sprays. It explains the physical processes of atomization as well as guidelines for designing atomizers. In addition, it demonstrates how the importance of the size and velocity of a particle contributes to improved spray characterization. Coverage includes general co
Download or read book Computational Investigation of Atomization written by Grétar Tryggvason and published by . This book was released on 1997 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: Atomization of liquid fuels is studied by numerical simulations. The Navier-Stokes equations are solved by a finite difference/front tracking technique that allows resolution of inertia! and viscous forces as well as the inclusion of surface tension at the deformable boundary between the fuel and the air. The secondary breakup of drops has been examined by extensive axisymmetric simulation of four systems: Impulsive and gradual disturbances for two different density ratios (1.15 and 10). At low density ratios. the density disappears as an independent control parameter and we have shown that the low density results apply to density ratios as high as two if we rescale time using the Boussinesq approximation. In addition to full simulations where the Navier-Stokes equations are solved a few inviscid simulations have also been done for the small density ratio case to isolate the effect of viscosity. The breakup of a planar interface has been examined. The presence of surface tension leads to the generation of fingers of interpenetrating fluids. In the limit of a small density ratio the evolution is symmetric, but for large density stratification the large amplitude stage consists of narrow fingers of the denser fluid penetrating into the less denser one. The dependency of the density difference is explained in terms of the advection of interfacial vorticity by the density weighted mean velocity.
Download or read book Proceedings of the 7th International Conference on Liquid Atomization and Spray Systems August 18 22 Seoul Korea written by Begell House Publication and published by Begell House Publishers. This book was released on 1997 with total page 518 pages. Available in PDF, EPUB and Kindle. Book excerpt: Interest and activity in research and development in the fields of atomization and sprays are increasing dramatically. At this conference, 170 abstracts were submitted from 20 different countries, collecting important research in basic atomization, fuel injection, measurement techniques, modeling of sprays, twin-fluid atomization, process/industry applications, spray combustion, and other areas of interest.
Download or read book Model Experiments on Atomization of Liquids written by Mintscho Popov and published by . This book was released on 1961 with total page 38 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Industrial Sprays and Atomization written by Ghasem G. Nasr and published by Springer Science & Business Media. This book was released on 2013-04-17 with total page 515 pages. Available in PDF, EPUB and Kindle. Book excerpt: An extensive critical compilation of the wide range of manufacturing processes that involve the application of spray technology, this book covers design of atomizers as well as the performance of plant and their corresponding spray systems. The needs of practising engineers from different disciplines: project managers, and works, maintenance and design engineers are catered for. Of interest to researchers in the field of liquid sprays, the book includes outlines of the contemporary and possible future research and challenges in the different fields of application and deals with: • sprays and their production; • sprays in industrial production processes; • processes involving vaporisation and cooling or cleaning of gases; • spray-surface impact processes; • fuel sprays for fixed plant; • spraying of hot surfaces for steel making and other metals; • spraying of molten metals. Guidance is given for the analysis and interpretation of experimental data obtained using different measurement techniques.
Download or read book Atomization and Sprays written by Arthur H. Lefebvre and published by CRC Press. This book was released on 2017-03-27 with total page 284 pages. Available in PDF, EPUB and Kindle. Book excerpt: The second edition of this long-time bestseller provides a framework for designing and understanding sprays for a wide array of engineering applications. The text contains correlations and design tools that can be easily understood and used in relating the design of atomizers to the resulting spray behavior. Written to be accessible to readers with a modest technical background, the emphasis is on application rather than in-depth theory. Numerous examples are provided to serve as starting points for using the information in the book. Overall, this is a thoroughly updated edition that still retains the practical focus and readability of the original work by Arthur Lefebvre.
Download or read book Handbook of Atomization and Sprays written by Nasser Ashgriz and published by Springer Science & Business Media. This book was released on 2011-02-18 with total page 922 pages. Available in PDF, EPUB and Kindle. Book excerpt: Atomization and sprays are used in a wide range of industries: mechanical, chemical, aerospace, and civil engineering; material science and metallurgy; food; pharmaceutical, forestry, environmental protection; medicine; agriculture; meteorology and others. Some specific applications are spray combustion in furnaces, gas turbines and rockets, spray drying and cooling, air conditioning, powdered metallurgy, spray painting and coating, inhalation therapy, and many others. The Handbook of Atomization and Sprays will bring together the fundamental and applied material from all fields into one comprehensive source. Subject areas included in the reference are droplets, theoretical models and numerical simulations, phase Doppler particle analysis, applications, devices and more.
Download or read book An Experimental Study of Aerated liquid Atomization written by Timothy Carl Roesler and published by . This book was released on 1988 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Experimental Studies on Atomization and Flux Distributions of Gas liquid Co axial Injectors written by Xiaoping Hu and published by . This book was released on 1996 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Computational and Experimental Study of Two Phase Flow in Pressure Swirl Atomizer written by Sherry Kwabla Amedorme and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
