Academic literature on the topic 'Airblast atomiser design'
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Journal articles on the topic "Airblast atomiser design"
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Rizk, N. K., and H. C. Mongia. "Calculation Approach Validation for Airblast Atomizers." Journal of Engineering for Gas Turbines and Power 114, no. 2 (April 1, 1992): 386–94. http://dx.doi.org/10.1115/1.2906603.
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In order to formulate a common approach that could provide the spray parameters of airblast atomizers, various processes of liquid preparation, breakup, and secondary atomization have been included in a semi-analytical calculation procedure. The air velocity components in the atomizer flow field are provided by mathematical expressions, and the spray droplets are considered to form at ligament breakup through a disturbance wave growth concept. The validation of the developed approach included the application to six atomizers that significantly varied in concept, design, and size. They represented both prefilming and plain-jet types, and the data utilized in the present effort were obtained with six different liquids. Satisfactory agreement between the measurements and the predictions has been achieved under wide ranges of air/fuel ratio and air pressure drop for various test liquids. The results of this investigation indicate the potential of using such an approach in the early phases of airblast atomizer design, and may be followed by more detailed calculations using analytical tools.
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Topal, Ahmet, Onder Turan, and Sıtkı Uslu. "Design, Manufacturing and Rig Test of a Small Turbojet Engine Combustor with Airblast Atomizer." International Journal of Materials, Mechanics and Manufacturing 3, no. 2 (2015): 97–100. http://dx.doi.org/10.7763/ijmmm.2015.v3.174.
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Tsai, S. C., and B. Viers. "Airblast Atomization of Viscous Newtonian Liquids Using Twin-Fluid Jet Atomizers of Various Designs." Journal of Fluids Engineering 114, no. 1 (March 1, 1992): 113–18. http://dx.doi.org/10.1115/1.2909985.
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Airblast atomization of viscous Newtonian liquids is carried out using coaxial twin-fluid jet atomizers of different nozzle sizes, slit angles, and slit cross sections for air flow. As the atomizing air swirls downstream along the liquid jet, waves form on the surface of the liquid jet. As a result, the liquid jet sheds ligaments which rapidly collapse into small drops. The atomized drop sizes can be described in terms of three dimensionless groups, namely, liquid-to-air mass ratio (M˙L/M˙A), Weber number (We), and Ohnesorge number (Z) in simple forms whose exponents and coefficients are determined by the best least square fit to the experimental results using the generalized inverse method. In addition, we found that the atomized drop sizes substantially decrease as the atomizing air pressure exceeds a threshold value which varies from less than 170 to 220 kPa depending on the nozzle size and the slit cross section.
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Rizk, N. K., J. S. Chin, and M. K. Razdan. "Modeling of Gas Turbine Fuel Nozzle Spray." Journal of Engineering for Gas Turbines and Power 119, no. 1 (January 1, 1997): 34–44. http://dx.doi.org/10.1115/1.2815559.
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Satisfactory performance of the gas turbine combustor relies on the careful design of various components, particularly the fuel injector. It is, therefore, essential to establish a fundamental basis for fuel injection modeling that involves various atomization processes. A two-dimensional fuel injection model has been formulated to simulate the airflow within and downstream of the atomizer and address the formation and breakup of the liquid sheet formed at the atomizer exit. The sheet breakup under the effects of airblast, fuel pressure, or the combined atomization mode of the airassist type is considered in the calculation. The model accounts for secondary breakup of drops and the stochastic Lagrangian treatment of spray. The calculation of spray evaporation addresses both droplet heat-up and steady-state mechanisms, and fuel vapor concentration is based on the partial pressure concept. An enhanced evaporation model has been developed that accounts for multicomponent, finite mass diffusivity and conductivity effects, and addresses near-critical evaporation. The presents investigation involved predictions of flow and spray characteristics of two distinctively different fuel atomizers under both nonreacting and reacting conditions. The predictions of the continuous phase velocity components and the spray mean drop sizes agree well with the detailed measurements obtained for the two atomizers, which indicates the model accounts for key aspects of atomization. The model also provides insight into ligament formation and breakup at the atomizer exit and the initial drop sizes formed in the atomizer near field region where measurements are difficult to obtain. The calculations of the reacting spray show the fuel-rich region occupied most of the spray volume with two-peak radial gas temperature profiles. The results also provided local concentrations of unburned hydrocarbon (UHC) and carbon monoxide (CO) in atomizer flowfield, information that could support the effort to reduce emission levels of gas turbine combustors.
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Chong, Cheng Tung, and Simone Hochgreb. "Spray Characteristics of an Internal-Mix Airblast Atomizer." Applied Mechanics and Materials 629 (October 2014): 125–30. http://dx.doi.org/10.4028/www.scientific.net/amm.629.125.
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Detailed characterisation of spray atomization of an injector is important for combustor design and modelling. In this paper, the effects of air/fuel mass ratio on the spray characteristics of an internal-mix airblast atomizer were examined. Distribution of the spatial mean droplet axial velocity and size were measured simultaneously using a phase Doppler anemometry (PDA). In general, small droplets are distributed at the center of the spray with maximum velocity. The droplet size increases with increasing radial distance from the spray centreline, but the drop velocity decreases to a minimum at the spray edge. Increasing the atomizing air/fuel mass ratio reduces fuel droplet size due to increased shear.
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Burby, Martin, Ghasem G. Nasr, Andrew J. Yule, and Leigh Morgan. "SINGLE-PHASE AERODYNAMIC FLOW FIELD VALIDATION OF NOVEL AIRBLAST ATOMIZER DESIGNS." Atomization and Sprays 20, no. 7 (2010): 565–79. http://dx.doi.org/10.1615/atomizspr.v20.i7.10.
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Hoshino, A., T. Sugimoto, T. Tatsumi, and Y. Nakagawa. "Development of a 30PS Class Small Gas Turbine and Its Power-Up Version." Journal of Engineering for Gas Turbines and Power 111, no. 2 (April 1, 1989): 225–31. http://dx.doi.org/10.1115/1.3240240.
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Due to the recent popularity of small and medium-sized industrial gas turbines in many fields, gas turbines below 100 SHP have been employed as prime movers, a power range traditionally reserved for diesel and gasoline engines. Generally speaking, however, small gas turbines have many design difficulties in thermal efficiency, high rotational speed, compact auxiliary equipment, etc., derived from limitations of their dimensions. Small gas turbines S5A-01 and S5B-01, which have 32 PS output power at standard conditions, have been developed and are being produced. Presently, a 30 percent growth rated power producer for S5A-02 and S5B-02 gas turbines is under development. These engines’ configurations are as follows: single-stage centrifugal compressor; single-stage radial turbine; single can combustor; hybrid fuel nozzle with pressure atomizer and airblast atomizer; fuel control valve with pulse width modulation system; electric motor drive fuel pump. In this paper, the authors describe the design features and development history of the base engine and the experimental results with the growth rated version.
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Eckstein, J., E. Freitag, C. Hirsch, T. Sattelmayer, R. von der Bank, and T. Schilling. "Forced Low-Frequency Spray Characteristics of a Generic Airblast Swirl Diffusion Burner." Journal of Engineering for Gas Turbines and Power 127, no. 2 (April 1, 2005): 301–6. http://dx.doi.org/10.1115/1.1789515.
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The low-frequency response of the spray from a generic airblast diffusion burner with a design typical of an engine system has been investigated as part of an experimental study to describe the combustion oscillations of aeroengine combustors called rumble. The atomization process was separated from the complex instability mechanism of rumble by using sinusoidal forcing of the air mass flow rate without combustion. Pressure drop across the burner and the velocity on the burner exit were found to follow the steady Bernoulli equation. Phase-locked particle image velocimetry measurements of the forced velocity field of the burner show quasisteady behavior of the air flow field. The phase-locked spray characteristics were measured for different fuel flow rates. Here again quasi-steady behavior of the atomization process was observed. With combustion, the phase-locked Mie-scattering intensity of the spray cone was found to follow the spray behavior measured in the noncombusting tests. These findings lead to the conclusion that the unsteady droplet Sauter mean diameter mean and amplitude of the airblast atomizer can be calculated using the steady-state atomization correlations with the unsteady burner air velocity.
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Durbin, M. D., and D. R. Ballal. "Studies of Lean Blowout in a Step Swirl Combustor." Journal of Engineering for Gas Turbines and Power 118, no. 1 (January 1, 1996): 72–77. http://dx.doi.org/10.1115/1.2816552.
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The design requirements of a modern gas turbine combustor are increasingly dictated by wide stability limits, short flame length, and uniform mixing. To achieve the best trade-off between these three factors, flame characteristics (length, shape, mixedness), lean blowout (LBO), and optimum combustor configuration should be investigated over a wide range of inner and outer air velocities, inner and outer vane angles, and co- versus counterswirl arrangements. Such an investigation was performed in a step swirl combustor (SSC) designed to simulate the fuel–air mixing pattern in a gas turbine combustor dome fitted with an airblast atomizer. It was found that an increase in the outer vane angle and a decrease in inner air velocity decreased the flame length. LBO was improved when outer flow swirl intensity was increased. An optimum hardware and velocity configuration for the SSC was found for inner swirl = 45 deg, outer swirl = 60 deg, coswirl direction, and inner air velocity = outer air velocity = 16 m/s. This optimum SSC configuration yielded: (i) low values of LBO, (ii) short flame length, (iii) uniformly mixed stable flame, and (iv) little or no variation in these characteristics over the range of operation of SSC. Finally, the co- versus counterswirl arrangements and the operation of the optimized combustor configuration are discussed.
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Harris, M. M., D. N. Marsh, E. A. Vos, and E. Durkin. "Flex Cycle Combustor Development and Demonstration." Journal of Engineering for Gas Turbines and Power 116, no. 3 (July 1, 1994): 534–41. http://dx.doi.org/10.1115/1.2906852.
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An innovative, “flex-cycle” combustion system has been developed for the Garrett Model 400-1 Integrated Power Unit (IPU), a 425 shp (317 kW) gas turbine engine designed for use on future fighter aircraft. Demonstration of this system required real-time transient operation of the combustor in a full-scale test rig. The transient testing was unique, having been performed with an electronic control, which modulated all combustor operating parameters according to programmed engine component maps, drag curves, fuel schedules, and selected ambient test conditions. The axially injected annular combustor is capable of engine starts in two seconds, as well as producing 200 shp (149 kW) for emergency use at all altitudes up to 50,000 ft (15,240 m). The combustion system is capable of switching operation from the emergency power stored energy (SE) mode to the normal-air breathing (NAB) auxiliary power mode without loss of engine power. The flex-cycle combustor supplies emergency power in the SE mode with a temperature rise of 2200°F (1222°C) and in the NAB mode with a temperature rise of 1600°F (889°C). Specific features that make these requirements possible include air-assisted simplex airblast fuel atomizers with integral check valves, and effusion-cooled combustor liner walls. This paper describes the flex-cycle combustion system design, test methods used, and significant test results. Steady-state performance, in both the SE and NAB operating modes, and real-time transient test results are discussed. The transient testing included rapid starts as well as transitions from the SE to NAB operating regimes.
Dissertations / Theses on the topic "Airblast atomiser design"
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Burby, Martin Laurence. "Design and evaluation of variable fuel-placement airblast atomizers." Thesis, University of Manchester, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.548665.
Full textConference papers on the topic "Airblast atomiser design"
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Rizk, N. K., and H. C. Mongia. "Calculation Approach Validation for Airblast Atomizers." In ASME 1991 International Gas Turbine and Aeroengine Congress and Exposition. American Society of Mechanical Engineers, 1991. http://dx.doi.org/10.1115/91-gt-305.
Full textAbstract:
In order to formulate a common approach that could provide the spray parameters of airblast atomizers, various processes of liquid preparation, breakup and secondary atomization have been included in a semi-analytical calculation procedure. The air velocity components in the atomizer flow field are provided by mathematical expressions, and the spray droplets are considered to form at ligament breakup through a disturbance wave growth concept. The validation of the developed approach included the application to six atomizers that significantly varied in concept, design, and size. They represented both prefilming and plain-jet types, and their data utilized in the present effort were obtained with six different liquids. Satisfactory agreement between the measurements and the predictions has been achieved under wide ranges of air/fuel ratio and air pressure drop for various test liquids. The results of this investigation indicate the potential of using such an approach in the early phases of airblast atomizer design, and may be followed by more detailed calculations using analytical tools.
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Rosskamp, Heiko, Michael Willmann, Jürgen Meisl, Robert Meier, Georg Maier, and Sigmar Wittig. "Effect of the Shear Driven Liquid Wall Film on the Performance of Prefilming Airblast Atomizers." In ASME 1998 International Gas Turbine and Aeroengine Congress and Exhibition. American Society of Mechanical Engineers, 1998. http://dx.doi.org/10.1115/98-gt-500.
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Advanced prefilming airblast atomizers are widely used for low emission combustors since they deliver a fine spray almost independently of the fuel flow rate. The droplet spectrum produced by this type of atomizer results from the aerodynamic forces at the atomizer edge and from the fuel properties prior to the film disintegration. Therefore, the wall film temperature is an important parameter affecting the fuel properties and in turn the atomization quality. Even though this atomizer type became well investigated (Lefebvre 1989, Rizk et al. 1987, Sattelmayer et al. 1989), still no general quantitative relationship between atomizer design and spray quality could be established since the fuel state at the atomizer edge cannot be precisely predicted yet. In extending earlier experimental and theoretical work on airblast atomizers (Sattelmayer et al. 1989, Himmelsbach et al. 1994, Willmann et al. 1997) and recent advances in the numerical modeling of wall film flows (Rosskamp et al. 1997a), this paper presents a numerical approach to judge the effect of fuel mass flow, air flow and the film length (i. e. length of atomizer lip) on the temperature of the liquid at the atomizer edge. The computer code developed provides detailed information on the wall film flow and the nozzle wall temperature. For the prediction of heat transfer to the film a new model has been developed which is based on measurements of the internal film flow (Elsäßer et al 1997). This new numerical approach can serve as a design tool to evaluate the effects of design modifications during atomizer development with view to their effect on atomization performance. The paper includes the theory for two-phase flow modeling and a generic parameter study that points out that the liquid loading and the length of the atomizer lip are important parameters in atomizer design. The calculations presented in the paper emphasize the necessity of coupled two-phase flow calculations because the film strongly interacts with the gas phase and the predicted atomizer performance is sensitive to changes in the air flow.
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Qi-Shou, Zhao, and Yu Yun-Fang. "Investigation of Jet-Filming Airblast Atomizer." In ASME 1985 International Gas Turbine Conference and Exhibit. American Society of Mechanical Engineers, 1985. http://dx.doi.org/10.1115/85-gt-185.
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The jet-filming airblast atomizer is another kind of airblast atomizer differing from a prefilming airblast atomizer. Its atomizing mechanism and performance were investigated experimentally and theoretically. The effects of design parameters on the mean droplet size SMD and the thickness of the liquid film were obtained. The inherent mechanism consisting of three atomizing processes was proved. From this, the performance curves of atomization and thickness of liquid film can be explained and the principles of design of this kind atomizer were derived. The results obtained show that the performance of the jet-filming airblast atomizer is better than that of the prefilming type, and it is simple in design. So it is advantageous to apply this kind of atomizer to an advanced aircraft engine.
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Chin, J. S., N. K. Rizk, and M. K. Razdan. "Experimental Investigation of Hybrid Airblast Atomizer." In ASME 1996 International Gas Turbine and Aeroengine Congress and Exhibition. American Society of Mechanical Engineers, 1996. http://dx.doi.org/10.1115/96-gt-464.
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As a means of overcoming the difficulties of achieving a satisfactory fuel atomization over the entire range of engine operation, both airblast forces and high pressure fuel injection are used in one hybrid atomizer design. The objectives of the present effort are to further improve the understanding of the important process of spray interaction in the hybrid atomizer flowfield, and to develop a relatively simple calculation approach that can relate the net effect of the interaction to the atomizer operating conditions. The ratio of the calculated average SMD for both the pilot and main prefilming device of the hybrid atomizer, each operating separately, to the SMD measured for the overall spray, obtained when both fuel devices were operating simultaneously, was used as an indication of the interaction between the two sprays. The experimental investigation demonstrated that stronger interaction between the pilot pressure nozzle spray and the prefilming main spray of the hybrid airblast atomizer occurred at higher pilot fuel pressure, larger pilot spray angle, or lower air pressure drop. It was also noticed that there was an optimum value of main fuel pressure, beyond which a decline in spray interaction was observed. The results indicated that by carefully selecting the pilot spray angle and flow capacities of the atomization devices, satisfactory atomization could be achieved even at lower air pressure drop. The interaction between the pilot and main sprays of the hybrid atomizer in configurations that utilized air swirlers surrounding the atomizer, was strongly dependent on swirler geometry. The extent of the interaction was attributed to changes in the air flowfield around and between the two sprays and the main filming process, all significantly affected the degree of utilization of the airblast effects.
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Li, Jibao, Arthur H. Lefebvre, and James R. Rollbuhler. "Effervescent Atomizers for Small Gas Turbines." In ASME 1994 International Gas Turbine and Aeroengine Congress and Exposition. American Society of Mechanical Engineers, 1994. http://dx.doi.org/10.1115/94-gt-495.
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An experimental investigation is conducted into the potential of effervescent atomizers as fuel injectors for gas turbine engines. The designs studied include three different configurations of multihole effervescent atomizers and an effervescent/airblast hybrid atomizer. In all tests the liquid employed is water. The spray characteristics investigated include drop size distributions and liquid flux distributions within the spray. The results obtained show that multi hole effervesent atomizers combine good atomization with uniform liquid flux distribution. This makes them especially suitable for application to annular combustors because they allow appreciable reductions to be made 1n the number of fuel injectors needed to achieve uniform circumferential fuel distribution. The hybrid atomizer also combines good atomization with the capability of wide cone angles. The only drawback exhibited by these atomizers is the need for a separate supply of atomizing air. This drawback could restrict their applications to non-aeronautical gas turbine engines.
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Acosta, Waldo A. "Experimental Study of the Spray Characteristics of a Research Airblast Atomizer." In ASME 1985 International Gas Turbine Conference and Exhibit. American Society of Mechanical Engineers, 1985. http://dx.doi.org/10.1115/85-gt-229.
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An experimental study of airblast atomization was conducted using an especially designed atomizer in which the liquid first impinges on a splash plate, then is directed radially outward and is atomized by the air passing through two concentric, vaned swirlers that swirl the air in opposite directions. The effect of flow conditions, air mass velocity (mass flow rate per unit area, ρAUA) and liquid to air ratio on the mean drop size was studied. Seven different ethanol solutions were used to simulate changes in fuel physical properties. The range of atomizing air velocities was from 30 to 80 m/s. The mean drop diameter was measured at ambient temperature (295 K) and atmospheric pressure.
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Micklow, Gerald J., Karthikeyan Shivaraman, and Insoo Cho. "Shroud Influence on Gas Turbine Airblast Atomizer Swirler Flowfields." In ASME 1995 International Gas Turbine and Aeroengine Congress and Exposition. American Society of Mechanical Engineers, 1995. http://dx.doi.org/10.1115/95-gt-332.
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The performance of high shear airblast fuel injectors for advanced gas turbine combustors is highly dependent on the design of the swirl vanes. The vanes may be of the straight or curved type. Curved vanes usually exhibit lower losses but straight vanes are also used due to lower cost and ease of manufacture. These type of vanes often operate under highly stalled conditions with high total pressure loss and a highly non-uniform exit velocity profile. This may produce poor fuel atomization with a non-uniform combustor fuel distribution resulting in lowered combustor efficiency and increased pollutant emissions. Constant turning curved vanes can also be easily manufactured. Properly designed vanes result in a greatly reduced total pressure loss. The exit velocity distribution is more uniform and higher in magnitude which can result in improved fuel atomization and distribution in the combustor. Further, the presence of a shroud is seen to have a major effect on the downstream flowfield. The present study compares standard helical flat vane performance with a low loss curved vane designed by the author for idle, and cruise conditions both with and without a shroud. The results from a three dimensional viscous numerical flow simulation show the curved swirl vane to be clearly superior to the standard flat helical swirl vane. The curved vane has a much lower total pressure loss with a more uniform exit velocity profile. This may result in improved combustor and engine performance and reduced pollutant emissions. The effect of the shroud was seen to reduce the size of the stall cell found in the vane passage for the helical vane. This resulted in a decrease in the magnitude of the axial velocity component in the outer vane passage and a decrease in the circumferential velocity component. This may result in a decrease in the swirl number. For the curved vane however, an increase in the magnitude of all velocity components was found which will result in a higher swirl number and better nozzle performance.
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Lai, Mark K., William G. Freeman, Paul R. Yankowich, Joe D. Bryant, and Peter Walterscheid. "High Pressure Spray Diagnostics Facility for Development and Evaluation of Aero-Engine Atomizer and Swirler Assemblies." In ASME Turbo Expo 2004: Power for Land, Sea, and Air. ASMEDC, 2004. http://dx.doi.org/10.1115/gt2004-53994.
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Recently, Honeywell has developed an unique industry capability of a high-pressure spray diagnostics facility to characterize 3D spray structures. Capability unique to Honeywell is highlighted. Major issues in measurement procedures under laser, industrial, and high-pressure environments and in acquisition and post-processing of 3D imaging are discussed. To characterize 3D spray, methodologies are described to quantitatively analyze vertical and horizontal spray images and to develop correlations of atomizer performances with engine (or rig) test data. Applications of this facility for a dual-orifice atomizer with an air shroud, a piloted airblast atomizer, and an assembly of a Lean-Direct Injection (LDI) atomizer with premixed swirlers are presented. The results indicate that, to have good correlations of atomizer performance with engine (or rig) test data, atomizers must be tested under high-pressure conditions and characterized three-dimensionally. Capabilities are shown to provide critical information for design and development of combustion systems.
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Chin, Ju S., Nader K. Rizk, and Mohan K. Razdan. "Study on High Liquid Pressure Internal Mixing Prefilming Airblast Atomization." In ASME 1998 International Gas Turbine and Aeroengine Congress and Exhibition. American Society of Mechanical Engineers, 1998. http://dx.doi.org/10.1115/98-gt-442.
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The objective of the present investigation is to provide better understanding of the hybrid atomization process in an effort to support the development of fuel injectors for future high performance / low emissions gas turbine combustors. A specially designed atomizer that incorporated two swirling air streams, and a prefilming device located upstream of the atomizer exit section was tested under a combined hybrid airblast and high liquid pressure mode. The experiments focused on evaluating the effects of several operating parameters, in particular the air / liquid ratio, on the atomization quality. The results demonstrated that, to accurately determine the role of the air / liquid ratio in the atomization process, the effects of liquid injection velocity and the relative air–liquid velocity need to be separated from that of the air / liquid ratio. Two approaches were used in the present investigation to deduce the actual effect of the air / liquid ratio: first, by reducing the air swirler flow areas, and second, by increasing the number of liquid injection holes. Both approaches enabled changing the air / liquid ratio without changing the air or liquid velocities. The atomization results indicate that changes in swirler flow area produce a stronger effect of the air / liquid ratio than that when liquid hole number was changed. For fixed air / liquid ratio, better atomization quality was achieved when both levels of air flow and liquid flow were high compared to when both flow rates were low. Also, the atomizer demonstrated a continuous improvement in atomization quality under very high air pressure drop, indicating a better utilization of the air kinetic energy over conventional airblast atomizers. The other important observation was that the dependency of the atomization process on air velocity was not constant, but rather changed with liquid pressure, air flow rate, and air pressure drop.
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Noll, B., H. Schütz, and M. Aigner. "Numerical Simulation of High-Frequency Flow Instabilities Near an Airblast Atomizer." In ASME Turbo Expo 2001: Power for Land, Sea, and Air. American Society of Mechanical Engineers, 2001. http://dx.doi.org/10.1115/2001-gt-0041.
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In the paper it is shown that statistical averaging of transport equations (URANS = Unsteady Reynolds Averaged Navier Stokes) imposes no inherent restriction concerning the ability to predict periodic or other deterministic transient flow processes. This even holds for periodic oscillations at relatively high frequencies lying in the spectral range of the inertial sub-range of flow turbulence. As an application, the unsteady behaviour of an isothermal swirling air flow through and behind an airblast-atomizer of a design typical for modern aeroengine combustors is treated. This flow exhibits self-excited oscillations at a frequency of 2.8 kHz. Computations of this flow behaviour based on the numerical solution of the unsteady statistically averaged Navier-Stokes equations are presented. The turbulence model employed in the computations is a k,ε-model modification for swirling flows. The transport equations are discretized by a Finite-Volume method on a curvilinear grid. Calculated mean velocity profiles as well as the predicted dynamic flow behaviour at the nozzle exit agree very well with appropriate LDV- and microphone-measurements.