Numerical simulation of pressure swirl atomizer for small. Cfd simulation of pressure swirl annular atomizer with. In this study the internal flow phenome of pressure swirl atomizer is investigated by using numerical method. Oct 01, 2009 design of pressure swirl atomizer the design of pressure swirl atomizer is carried out as per the design methodology presented in the previous section. Atomizers are used in many engineering applications including spray combustion in furnaces, diesel engines, direct injection petrol engines and gas turbine engines. Pressure swirl atomizers are widely used in airbreathing gas turbine engines as they have good atomization characteristics and are relatively simple and inexpensive to manufacture. The pressure swirl atomizer is designed and developed for tubular combustion chamber of micro gas turbine engine with spray cone angle of 60degrees, 90degrees and 120. The design of pressure swirl atomizers sciencedirect. Numerical simulation of internal flow in a largescale.
Numerical analysis of pressure swirl atomizer scientific. The free surface inside the vortex chamber and within the hollowconeprimary atomization zone is simulated with a fourth order scheme thereby permitting investigation of highly distorted surfaces up to the point where atomization occurs. A laminated array of pressure swirl atomizers forms spray plate that produces a fine mist or spray of liquid. As a result of the swirling motion centrifugal forces within the swirl.
Another important type of atomizer is the pressure swirl atomizer, sometimes referred to by the gasturbine community as a simplex atomizer. However, when applying cfd in a new way to model fluiddynamic behavior, some form of validation is necessary for reliable results. The importance of pressure swirl atomizers internal geometries becomes more pronounced when the spray has reached a steady state. Experimental investigations of spray generated by a pressure swirl atomizer journal of the energy institute, vol. Numerical simulation of laminar and turbulent two phase flow. The sauter mean diameter smd and the spray cone angle. The hybrid air blast atomizer takes advantage of both the pressure swirl injector at low fuelow rates and air blast atomization at high fuel ows. Microfabrication and laser diagnosis of pressureswirl atomizers article pdf available in journal of microelectromechanical systems 5. Pressure swirl or simplex atomizers are commonly used in a number of industrial applications for liquid atomization, including fuel injection systems for gas turbine engines, spray drying, and paint sprays. Good agreements were obtained for discharge coefficient.
Pdf experimental investigation of a pressure swirl atomizer. Pressure swirl atomizers occupy a special position amongst other atomizers because they differ. In the airless atomization process, high pressure forces fluid through a small nozzle. A new theoretical model was developed utilizing energy conservation methods in order to determine the fullyatomized crosssectional sauter mean diameters of pressure swirl atomizers. The complete combustion with a relatively low temperature may be ensured so that the emission of nitrogen oxides may be. The first phase of calculations refers to an ideal liquid. The smd is estimated through the use of a model originally developed for fanspray atomizers and extended for pressure swirl atomizers. 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.
Us6016969a laminated array of pressure swirl atomizers. This can be achieved by using an axial jet or with the. A detailed boundarylayer assessment led to the development of a new viscous dissipation model for droplets in the spray. A fully nonlinear boundary element method bem model has been developed to simulate the pressure swirl or simplex atomizer. Effect of geometric parameters on simplex atomizer performance. Three geometric elements of atomizers, including tangential ports, swirl chamber, and discharge orifice, pose a significant effect on the sauter mean diameter of pressure swirl atomizers. Experimental and numerical investigation of a pressure. Design procedure and experimental evaluation of pressure. The main difficulty in the numerical simulation of the flow in a pressure swirl atomizer is the accurate tracking of the liquidair. Recently, kubitschek and weidman 2,3 made an important contribution by making the full linear stability analysis of a helical column of. As stated earlier, the high swirl velocity in pressure swirl atomizers results in an air core at the centerline of the atomizer and fig. In the present work a theoretical model has been described, based on the maximum entropy formalism principle, for the determination of the drop size distribution in a spray issued from a pressure swirl atomizer.
Pdf microfabrication and laser diagnosis of pressure. Converging swirling liquid jets from pressure swirl. The input variables to the design are summarized in table1 while table2 gives the primary dimensions of designed nozzles at spray cone angles of 60degrees, 90degrees and 120degrees. May 23, 2012 experimental study of a heavy fuel oil atomization by pressure swirl injector in the application of entrained flow gasifier chinese journal of chemical engineering, vol. The unstructured mesh with tetrahedral elements are used. Surface tension causes an atomized liquid to break up into spherical droplets. Factors influencing the circumferential liquid distribution. Prediction of drop size distribution in a spray from a. Method of production, experimental characterization and a semiempirical model. Improved semiempirical correlation to predict sauter mean.
Intro to chemistry, basic concepts periodic table, elements, metric. The dualfuel circuit pressure swirl atomizers are numerically studied by the finite volume method with the inside kerosene flowing under the boundary condition of massflowinlet 300lh580lh and pressure inlet 1. Pressurescaling of pressureswirl atomizer cone angles. The droplets sauter mean diameter smd and the spray cone angle are evaluated and made to fit the calculated atomizer dimensions. Surface waves as well as vorticity waves on the aircore surface can be discerned figure 4. Low nox liquid fuel oil atomizer spray plate and fabrication method thereof. Lefebvre 7 discussed the application of pressure swirl atomizers in gas turbine combustion chambers. Method for manufacturing pressure swirl atomizers us6016969a en 19961206. Optimization of a high pressure swirl injector by using. Ingham university of leeds west yorkshire, leeds ls2 9jt, u. Laminated array of pressure swirl atomizers us6024301a en 19981016.
Computational and experimental study of two phase flow in. Dimensional drawing of pressure swirl atomizer all dimensions are in mm figure 4. Initially, a description of the fuel injection system and the nozzle itself is given, followed by a general discussion. Ressure swirl atomizers simplex atomizers are widely used for liquid fuel atomization in gas turbine engines for propulsion and power generation applications. The pressure swirl atomizer, also known as simplex atomizer with its dimensions are shown in figure 1. Highfidelity simulations of fuel injection and atomization. The pressure swirl atomizer has wider stability region while the main airblast atomizer provides improved combustion e ciency. They are also commonly used in applying agricultural chemicals to crops, paint spraying, food processing and cooling of nuclear cores. Review design and experimental investigation of internally. Measurements of circumferential liquid distribution are carried out over ranges of injection pressure from 0. Drop size distribution is an important characterizing parameter of a spray. Design methodology and development of pressure swirl atomizer. Numerical analysis and empirical correlations to predict smd.
The fuel injection pressure at inlet is kept 6 bar, 9 bar, 12 bar, 15 bar and 18 bar and ambient pressure and temperature is. Pdf microfabrication and laser diagnosis of pressureswirl. An improvement of a swirl type fuel atomizer is disclosed in which a plurality of projections, grooves or recesses are equiangularly formed around an opening of a singlenozzle hole so that the liquid fuel injected may be divided into a plurality of fuel spray patterns. Modeling of pressureswirl atomizers for gdi engines.
Nov 19, 2014 design of pressure swirl atomizer 4 duration. In a preferred embodiment, a plate adjacent to a fluid reservoir provides an array of aperture sets. The atomizers may be arrayed in a custom manner that may be made application specific for greater efficiency. The visualizations of spray pattern and droplet size spatial distribution with variations of pressure differential for pressure swirl atomizer are key issues in swirl cup or internally staged airblast fuel injectors because pressure swirl atomizer provides primary atomization or pilot spray which affects the quality of airfuel mixing in lean. Effect of pressure swirl atomizer geometry on spray. Schematics of pressure swirl atomizer 1 for some applications a spray in the form of a solid cone is preferred. Internal flow field figure 1 shows a schematic of simplex atomizer geometry. Pressure airless atomization other terms the spray coating industry uses for pressure atomization include airless, airassisted airless, hydrostatic, and hydraulic technology. Swirl atomizer article about swirl atomizer by the free. Design method 8 the aim of the design is to determine the dimensions of a the following data. The fluid emerges as a solid stream or sheet at a high speed. The atomization character includes the spray angle, the water flow rate, the sauter mean diameter smd, the velocity of the particles and. The numerical simulation of designed pressure swirl atomizer for small scale gas turbine combustion chamber is carried out using ansys fluent.
The simple modification in pressure swirl atomizer is undertaken for the development of internally mixed pressure swirl atomizer. Pressure swirl atomizers, also known as simplex atomizers, are used commonly in many industries, including aerospace, automotive, pharmaceuticals and others. Computational evaluation of spray characteristics in. Despite of simple geometry and operation of a pressure swirl atomizer, flow behavior through it is complicated due to. Process modeling pressureswirlgasatomization for metal. Numerical analysis and empirical correlations to predict. The atomizer selected for this study is a simplex pressure swirl fuel nozzle seen in fig. To validate the model, results for base injector were compared in the steady state operation with those of available experiments in the literature. Pdf experimental investigation of a pressure swirl. The psga atomizer design, especially the pressure swirl nozzle, is sophisticated and has been used to produce fine spherical powders of low melting point metals with small median diameter and. Cfd simulation of pressure swirl annular atomizer with large.
Design of pressure swirl atomizer the design of pressure swirl atomizer is carried out as per the design methodology presented in the previous section. The most popular gi fuel atomizer is the pressureswirl atomizer or sometimes known by the gas turbine community as the simplex atomizer. Pressure swirl atomizer is widely used in many industrial applications such as fuel injection in gas turbine, internal combustion engine and liquidfuel rocket, spray drying, spray in firing and agricultural nozzles. Effect of geometric parameters on simplex atomizer. Experiments and modeling of discharge characteristics in watermist sprays generated by pressure swirl atomizers 14 november 2012 journal of thermal science, vol.
The nozzle used is a large flow capacity pressure swirl nozzle with diameter 1. Surface tension is the force that causes fluids to pull. Atomization is the process of breaking up liquids into droplets. This information will be used to design hybrid twinfluid pressure swirl injectors that have a. Modeling of pressure swirl atomizers for gdi engines 1999010500 a new simulation approach to the modeling of the whole fuel injection process within a commonrail fuel injection system for directinjection gasoline engines, including the pressure swirl atomizer and the conical hollowcone spray formed at the nozzle exit, is presented.
A circular outlet orifice is preceded by a swirl chamber into which liquid flow through a number of tangential holes or slots. Modeling of pressureswirl atomizers for gdi engines 1999010500 a new simulation approach to the modeling of the whole fuel injection process within a commonrail fuel injection system for directinjection gasoline engines, including the pressure swirl atomizer and the conical hollowcone spray formed at the nozzle exit, is presented. Twentythird symposium international on combustionthe combustion institute, 1990pp. This work describes a procedure for designing a pressure swirl atomizer. Cfd and experimental analysis of swirl type single. Three different custom made pressure swirl atomizers are investigated.
The fluid to be atomized enters through one, two or more tangential inlet ports, passes through the swirl chamber with a conical convergent part and exits through a cylindrical orifice. The orifice diameter of the pressure swirl injector is 0. Mean drop sizes from pressureswirl nozzles journal of. In proceedings of the 18th annual conference on liquid atomization and spray systems, zaragoza, spain, paper 028. The spray plate is typically formed of a plurality of laminated plates. In the present study, the spray is formed and exit through annulus area of the orifice. Atomization quality of liquids has a great importance on the performance of combustion engines. In this study, the research team developed a fluent model to predict the liquid atomization and spray.
Design methodology and development of pressure swirl. In the following sections, an alternative approach to the modeling of gdi sprays injected from a pressure swirl atomizer connected to a commonrail fuel injection system is presented. Effects of inlet pressure and inlet flow rate on the flow. Nov 19, 2014 design of pressure swirl atomizer4 duration. The swirling liquid creates a core of air or gases which extents from the discharge orifice to the rear of the swirl chamber. Upon reaching a steady state, the discharge coefficient and the spray cone angle of a pressure swirl atomizer largely depends on its internal geometry and the fluid properties 8, 9. This study extends the classical results of decorso and kemeny, 1957, effect of ambient and fuel pressure on.
Theoretical prediction of sauter mean diameter for pressure. Nonlinear simulation of free surfaces and atomization in. A spray is a collection of a variety of sizes of fluid droplets moving in a controlled fashion. Simulation and experimental study on the atomization. In a simplex atomizer, the fuel is forced under high pressure to enter a swirl chamber through inlet slots at the outer wall. Pressure swirl atomizers are quite common due to their favorable atomization characteristics, low clogging tendency and geometrical simplicity. Experimental investigation of a pressure swirl atomizer spray.
The experimental investigations suggest that spray half cone angle tends to decrease with increase in injection pressure for conventional pressure swirl atomizer. Liquid atomization out of a full cone pressure swirl nozzle. Experimental investigations of spray generated by a pressure. These nozzles work by forcing a liquid under high pressure into a swirl chamber in which the fluid gains tangential momentum and exits through a small orifice or nozzle. Quasicylindrical approximation to the swirling flow in an. In this paper the atomization character of the pressure swirl injector was measured by using the phase doppler particle analyzer pdpa in the section of 150 mm below the outlet of the orifice.
In this study, a semiempirical model improved from the surface wave breakup theory was established to predict sauter mean diameter of pressure swirl atomizers. An experimental investigation was conducted to study the effects of increased ambient pressure up to 6. Modeling of gasliquid flow in pressure swirl atomizers. The spray characteristics from a pressure swirl nozzle, a widely used device in agriculture, combustion and aerospace, have been investigated in this study experimentally with focus on the effects of nozzle hole size and injection pressure on spray morphology, velocity distribution, and spray angle. The atomizer is a scaleup of a danfoss pressure swirl atomizer designed for domestic boilers. Computational evaluation of spray characteristics in pressure. Atomization the process of atomization is one in which liquid jet or sheet disintegration. In this research work, a novel idea of using a pressure swirl single. Disturbances propagating on the surface of this sheet cause its disruption into ligaments and. The aircore inside the pressure swirl atomizer resembles a drilling bit. This type of atomizer accelerates the liquid through nozzles known as swirl ports into a central swirl chamber.