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Training / Education
2015-06-15
Liquid fuel atomization and spray formation is the heart of the majority of stationary and mobile power generation machines that we rely on. This seminar focuses on the process of liquid atomization and spray formation and how it relates to fuel injection systems and emission of pollutants in modern engines. The seminar begins with background coverage of terminology, the purposes of liquid atomization and spray formation, and different designs of atomizers and nozzles employed in various industries. The focus is then directed to gasoline and diesel fuel injections, injector designs, and performance requirements for optimum engine operation with lowest possible emission of harmful pollutants.
Training / Education
2014-11-07
The improved efficiencies of the modern diesel engine have led to its increased use within the mobility industry. The vast majority of these diesel engines employ a high-pressure common rail fuel injection system to increase the engine's fuel-saving potential, emissions reduction, and overall performance. This one-day seminar will begin with a review of the basic principles of diesel engines and fuel injection systems. Diesel and alternative fuels will be discussed, followed by current and emerging diesel engine applications. The majority of the day will be dedicated to the common rail system itself, beginning with a comprehensive overview of the complete system.
Event
2014-10-22
This session is devoted to experimental and computational work in the area of fuel injection systems and sprays. Topics include: spray characterization, cavitation, multi-phase jet modeling, CFD models for spray processes, wall films and impingement, hydraulic circuit analysis, and dissolved gas effects. Studies of both gasoline and diesel fuel sprays and fuel injection equipment are encouraged.
Event
2014-10-21
This session is devoted to experimental and computational work in the area of fuel injection systems and sprays. Topics include: spray characterization, cavitation, multi-phase jet modeling, CFD models for spray processes, wall films and impingement, hydraulic circuit analysis, and dissolved gas effects. Studies of both gasoline and diesel fuel sprays and fuel injection equipment are encouraged.
Event
2014-10-21
This session is devoted to experimental and computational work in the area of fuel injection systems and sprays. Topics include: spray characterization, cavitation, multi-phase jet modeling, CFD models for spray processes, wall films and impingement, hydraulic circuit analysis, and dissolved gas effects. Studies of both gasoline and diesel fuel sprays and fuel injection equipment are encouraged.
Event
2014-10-21
This session is devoted to experimental and computational work in the area of fuel injection systems and sprays. Topics include: spray characterization, cavitation, multi-phase jet modeling, CFD models for spray processes, wall films and impingement, hydraulic circuit analysis, and dissolved gas effects. Studies of both gasoline and diesel fuel sprays and fuel injection equipment are encouraged.
Technical Paper
2014-10-13
Mayank Mittal, Harold Schock
A single-cylinder gasoline direct-injection engine was used for fuel spray and combustion visualizations with optical access to the combustion chamber. Experiments were conducted to investigate the effect of fuel injection pressure on spray and combustion characteristics inside the engine cylinder. A multi-hole high-pressure production injector was used with fuel pressures of 5 and 10 MPa. A Mie scattering technique was used to image the liquid phase of the fuel dispersion. The obtained spray images were then used to study the macroscopic spray characteristics such as spray structure, spray tip penetration and spray angle. Combustion visualization tests were performed to evaluate the effect of fuel injection pressure on combustion characteristics. In-cylinder pressure signals were recorded for the combustion analyses and synchronized with the high-speed combustion imaging recording. Results showed that higher fuel injection pressure led to faster spray tip penetration and more spray area for better fuel-air mixing.
Technical Paper
2014-10-13
Zaira Aline Kuensch, Stephanie Schlatter, Karri Keskinen, Tuomo Hulkkonen, Martti Larmi, Konstantinos Boulouchos
Direct injection of natural gas in engines is considered a promising approach toward reducing engine out emissions and fuel consumption. As a consequence, new gas injection strategies have to be developed for easing direct injection of natural gas and its mixing processes with surrounding air. In this study, the behavior of a hollow cone gas jet generated by a piezoelectric injector was experimentally investigated by means of tracer-based planar laser-induced fluorescence (PLIF). Pressurized acetone-doped nitrogen was injected in a constant pressure and temperature measurement chamber with optical access. The jet was imaged at different timings after start of injection and its time evolution was analyzed as a function of injection pressure and needle lift. The acquired PLIF images provide quantitative information about temporal evolution of the transient gas jet in terms of penetration length and jet width, while they qualitatively describe spatial distribution in terms of local gas concentration, estimated average jet concentration and jet volume.
Technical Paper
2014-10-13
Romaeo Dallanegra, Rinaldo Caprotti
Internal Diesel Injector Deposits (IDIDs) have been known for some time. With the latest powertrains becoming ever more sophisticated and reliant on efficient fuel delivery, the necessity for a continued focus on limiting their formation remains. Initial studies probed both carbonaceous based/ashless polymeric and sodium salt based IDIDs. The reported occurrence of the latter variety of IDID has declined in recent years as a result of the removal of certain additives from the diesel distribution system. Conversely, ashless polymeric based deposits remain problematic and a regular occurrence in the field. The body of work presented in this contribution is an extension to that reported in SAE paper 2014-01-1401 which showed how a particular Fuel Borne Catalyst (FBC) additive has the ability to prevent the formation of ashless polymeric deposits formed from the reaction of Poly-Isobutylene Succinic Imides (PIBSI) with fatty acid and the ability for the same additive to also be neutral towards the formation of sodium salt based deposits.
Technical Paper
2014-10-13
Martin Krämer, Eberhard Kull, Markus Heldmann, Michael Wensing
Introduction Modern concepts of downsized DI gasoline engines set up high requirements on the injection system to meet the emission targets. The fundamental knowledge and understanding of spray propagation physics are essential for the development of nozzles and injection strategies, due to reduced displacements in combination with the continuing trend of elevated fuel pressures. The experimental results presented in this paper are carried out in a high pressure and high temperature injection chamber. Object of investigation is a GDI multihole injector, optically analyzed with imaging Shadowgraphy and Phase Doppler Anemometry (measurement planes at two distances from nozzle tip), for macro- and microscopic spray parameters. The results are used to discuss a phenomenological model of spray propagation and describe influence factors and possibilities to control penetration of gasoline sprays in a fuel pressure range up to 380bar. Results and Discussion The propagation behaviour of gasoline sprays can be divided in two parts.
Technical Paper
2014-10-13
Alessandro Ferrari, Pietro Pizzo, Federica Paolicelli
A numerical-experimental activity on the latest generation of solenoid Common Rail injectors with the pressure balanced pilot-valve has been carried out. This design solution has been recently introduced in the market in order to reduce fuel static leakages and improve both the efficiency and control of the solenoid CR technology. An experimental campaign has been performed at the hydraulic test rig to characterize the fuel leakages of the newly designed solenoid injector with respect to the injectors equipped with the standard pilot-valve layout and to the piezoelectric indirect-acting injectors that are claimed to feature reduced leakages. An accurate numerical model of the solenoid injector with the pressure balanced pilot-valve has been realized in order to better assess the cause and effect relationships between design changes and experimental performance. The one-dimensional model performance has been assessed by means of the comparison between numerical outcomes and experimental data, which refer to injected flow-rate and injector-inlet pressure time distributions and have been measured for single and multiple injection events.
Technical Paper
2014-10-13
Yuhan Huang, Sheng Huang, Peng Deng, Ronghua Huang, Guang Hong
Ethanol direct injection (EDI) is a new technology to make the use of ethanol fuel more effective and efficient in spark ignition engines. Fuel temperature is one of the key factors which determine the evaporation process of liquid fuel spray, and consequently influence the combustion and emission generation of the engine. To better understand the mixture formation process of the EDI spray and provide essential data for engine modelling, experiments were conducted on a constant volume combustion chamber in engine-like conditions. The high speed Shadowgraphy imaging technique was used to capture the ethanol spray behaviours. The experiments covered a wide range of fuel temperatures, ranging from 275K (non-evaporating) to 400K (flash-boiling). Particularly the transition of the ethanol spray from normal-evaporating to flash-boiling was investigated. The temporal Shadowgraphy spray images, spray tip penetration, angle and projected area were applied to evaluate the evaporation of EDI spray under different fuel temperature conditions.
Technical Paper
2014-10-13
Luca Marchitto, Simona Merola, Cinzia Tornatore, Gerardo Valentino
Alcohols are largely used in spark-ignition (SI) engines as alternative fuels to gasoline. Particularly, the use of n-butanol meets growing interest due to its properties that are similar to gasoline, if compared with other alcohols. This paper aims to make a comparative analysis on the atomization process of gasoline and n-butanol fuel injected by a multi-hole injector nozzle for spark ignition engines. Imaging and Phase Doppler Anemometry techniques were applied to investigate the behaviour of a spray emerging from a six-hole injector for spark ignition engine applications. Two different fuels were investigated: commercial gasoline and pure n-butanol. Fuels were injected at two pressures: namely at 5 and 10 MPa, in a test vessel at quiescent air conditions, ambient temperature and backpressure. Injection duration was set to deliver the same fuel mass for both fuels. Image sequences of the spray were collected by a high speed camera in order to characterize spatial-temporal evolution of the spray.
Technical Paper
2014-10-13
Alessandro Montanaro, Luigi Allocca, Ugo Sorge, Anqi Zhang, Michela Costa
Diesel sprays from an axial-disposed single-hole injector were studied under vaporizing conditions in a constant-volume combustion vessel. A hybrid Shadowgraph/Mie-scattering imaging setup was used to acquire the liquid and vapor phases of the fuel distribution in a near-simultaneous visualization mode by a high-speed camera (40,000 fps). Two geometries of the injector duct were used, identified with k-factors 0 and 1.5, having the exit-hole diameter of 0.1 mm and the ratio L/d =10. The studies were performed at 70, 120, and 180 MPa injection pressures, 25.37 kg/m3 ambient gas density, and the gas temperature in the vessel of 373/453 and 900 K for non-vaporizing and vaporizing conditions, respectively. The instantaneous positions of the front of the spray, extracted from the images and processed by an assessed software, defined the tip penetrations of the liquid and vapor phases at the various operating conditions. The FIRE-AVL provisional code was used to predict the jet behavior calibrating the sub-models with the experimental data.
Technical Paper
2014-10-13
Yoshimitsu Kobashi, Yusuke Kimoto, Satoshi Kato
Ethanol is a promising alternative to fossil fuels because it can be produced from biomass resources that are renewable. Due to the amount of production, however, the use would be limited to blends with other conventional fuels. Ethanol-fuel blends are azeotropic and have unique vaporization characteristics different from blends composed of aliphatic hydrocarbons, so that the authors have developed a numerical droplet vaporization model which takes into account the vapor-liquid equilibrium of azeotrope and, additionally, higher latent heat of vaporization (LHV) of ethanol. In the present study, an experimental validation of the developed vaporization model was made through a comparison of single droplet vaporization tests. Ethanol-n-heptane blends in which n-heptane is assumed to be a representative component of gasoline were used for the comparison. The trend of calculated droplet vaporization rates were in good agreement with that of the experimental data, in terms of the change in the mixing fraction.
Technical Paper
2014-10-13
Hiroshi Kawanabe, Sho Tanaka, Shota Yamamoto, Hirokazu Kojima, Takuji Ishiyama
Single-excite and dual fluorescence PLIF was applied to a diesel spray of two-component fuel with different boiling points. The spray was formed by injecting fuel into a constant volume vessel under high-temperature and high-pressure conditions. The fluorescence emitted from the two tracers for fuel was optically separated to measure the concentration of each component. Mixture formation was investigated based on concentration distributions of each fuel-component. The fuel concentration was derived based on the change in fluorescence intensity due to temperature and the assumption of adiabatic mixing of fuel and surrounding fluid. The change in mixture distribution due to the difference of vaporization characteristics was investigated. The results show that the two components basically distribute similarly. Concentration of the high boiling component becomes slightly higher upstream base region in a spray.
Technical Paper
2014-10-13
Tianyou Wang, Xiangzan Meng, Xiaochao Song, Ming Jia
It has been recognized that density, viscosity, surface tension, and volatility of liquid fuel are of great importance on the atomization and vaporization characteristics of biodiesel spray. This paper presents a comprehensive physical property prediction of biodiesel fuel for spray modeling with most recently developed property prediction models. The temperature-dependent properties of a soy methyl ester (SME) biodiesel were well predicted by the updated prediction methods. Then, the physical properties of the SME biodiesel were added into the KIVA-3V fuel library. By using the well predicted fuel properties, the spray behaviors of SME were successfully simulated by the KIVA-3V code under late-cycle post-injection, conventional diesel injection, and early-injection engine-relevant conditions. The simulation results agree reasonably well with the available experimental liquid penetrations under conditions of various ambient densities and temperatures. The different properties between diesel and SME fuels have pronounced effect on their different spray behaviors under the late-cycle post-injection conditions.
Technical Paper
2014-10-13
Dehao Ju, Tingting Zhang, Jin Xiao, Zhen Huang
This study is to compare and qualify the macroscopic spray characteristics of dimethyl ether (DME) and diesel actuated through a plain-orifice atomizer. A moderate injection pressure of 6.0 MPa was operated to produce “stable” sprays vertically into atmosphere in this work. In order to quantitatively investigate the flash-boiling atomization, the sprays actuated under atmospheric conditions were directly imaged at a frame rate of 12,000 fps and analyzed by the multi-threshold algorithm. The spray images were acquired at various times after the start of actuation using a high-speed visualization system. The light intensity level of the image implies the local relative mass concentration of droplets in the spray. The transient continuous spray cone angles were measured at each case. Transient contour plots of DME spray images at various thresholds were analyzed and compared with turbulent round jets of diesel. The relative mass concentration distributions and continuous cone angles of the sprays during the start, development and end periods of the atomization were discussed for two different sprays.
Technical Paper
2014-10-13
Markus Behringer, Pavlos Aleiferis, Dave OudeNijeweme, Paul Freeland
One of the latest advancements in injector technology is laser drilling of the nozzle holes. In this context, the spray formation and atomisation characteristics of gasoline, ethanol and 1-butanol were investigated for a 7-hole spark eroded injector and its ‘direct replacement’ Laser-drilled injector using optical techniques. In the first step of the optical investigation, high-speed spray imaging was performed in a quiescent injection chamber with global illumination using diffused Laser light. The images were statistically analyzed to obtain spray penetration, spray tip velocity and spray ‘cone’ angles. Furthermore, droplet sizing was undertaken using Phase Doppler Anemometry (PDA). A single spray plume was isolated for this analysis and measurements were obtained across the plume at a fixed distance from the nozzle exit. The droplet measurements were grouped into bins and maps were created showing droplet sizes and velocities against time and position during and post injection. All tests were performed at 120 bar fuel pressure, two injection chamber ‘back’ pressures (0.5 bar and 1 bar) and two injector temperatures (20 °C and 80 °C), to examine effects relevant to typical engine operating conditions with early intake stroke injection strategies, including fuel flash boiling.
Technical Paper
2014-10-13
Ogheneruona E. Diemuodeke, Ilai Sher
The theory of liquid jet instabilities has been developed under several assumptions, which include the assumption that the jets breakup processes are quasi-steady and isothermal. Accelerated liquid fuels are normally injected into an elevated combustion-chamber temperature to maintain a desirable homogeneous combustible mixture – liquid vapour and air. The accelerated jet breakup may be induced by cavitations, turbulent, hydrodynamic and aerodynamic forces interaction and variation in fluid properties. The absolute majority of studies have been devoted to the extensive study on some of the effects that cause jet instability and breakup, while others are still at their infant study. In particular, relatively few researchers have studied the combined effects of jet acceleration and non-isothermal condition on jet instability and breakup, despite its practical relevance in liquid fuel spray and combustion. Specifically, liquid fuel jets are highly transient under pulsed injection technique, which has been demonstrated to maintain better fuel economy and emissions reduction.
Technical Paper
2014-10-13
Tianyou Wang, Xiangzan Meng, Xiaochao Song, Ming Jia
Spray behaviors of pure biodiesel and its blend with conventional diesel have been substantially studied in the last decade. However, the studies on the spray behaviors of pure fatty acid methyl esters (FAMEs) are scarce. The primary components of most biodiesel fuels are methyl palmitate (C16:0), methyl stearate (C18:0), methyl oleate (C18:1), methyl linoleate (C18:2) and methyl linolenate (C18:3), and methyl laurate (C12:0) is also the dominant component of some biodiesels. In this study, the spray behaviors of the aforementioned six FAMEs in biodiesel fuels under engine-relevant conditions were numerically studied using the KIVA-3V code. The physical properties needed for spray modeling were predicted with most recently developed property prediction models and added into the fuel library of KIVA-3V. The transient behaviors of liquid penetrations and vaporization characteristics of these FAMEs were numerically studied under various engine-relevant conditions. Results showed that the esters of 18-carbon-atom acids have much longer liquid lengths than those of C16:0 and C12:0 with relatively shorter carbon chain length.
Technical Paper
2014-10-13
Daliang Jing, Hongming Xu, Shi-jin Shuai, Zhi Wang, Yanfei Li
Fuel spray atomization process is known to play a key role in affecting mixture formation, combustion efficiency and soot emissions in direct injection engines. The fuel spray CFD modeling technology can be an effective means to study and predict spray characteristics such as penetration, droplet size and droplet velocity, and as a consequence, to drastically reduce experimental work during the engine development process. For this reason, an accurate numerical simulation of the spray evolution process is imperative. Different approaches and various models based on aerodynamically induced breakup mechanism have been implemented to simulate spray atomization process in earlier studies, and the effects of turbulence and cavitation from the injector nozzle is recently being concerned increasingly by engine researchers. In this study, an enhanced turbulence and cavitation induced primary breakup model combining aerodynamic breakup mechanism is developed and applied into the Kiva 3V code. The proposed model improves the primary breakup accuracy by optimizing the turbulence induced breakup process, controlling the transition process of the primary and secondary breakups and employing a new child droplet size function and a new parent droplet size reduction rate.
Technical Paper
2014-10-13
Aleš Srna, Michele Bolla, Konstantinos Boulouchos, Yuri M. Wright
This study presents an application of the conditional moment closure (CMC) combustion model to marine diesel sprays. In particular, the influence of fuel evaporation terms has been investigated for the CMC modeling framework. This is motivated by the fact that substantial overlap between the dense fuel and flame area is encountered for sprays in typical large two-stroke marine diesel engines which employ fuel injectors with orifice diameters of the order of one millimeter. Simulation results are first validated by means of experimental data from the Wärtsilä optically accessible marine spray combustion chamber in terms of non-reactive macroscopic spray development. Subsequently, reactive calculations are carried out and validated in terms of ignition delay time, ignition location, flame lift-off length and the temporal evolution of the flame region. Finally, the influence of droplet terms on spray combustion is analyzed in detail. The effect of evaporation into the mixture fraction variance transport equation was seen to play a prominent role concerning autoignition and flame stabilization: both ignition delay and flame lift-off length are considerably increased when evaporation effects are included.
Technical Paper
2014-10-13
Chengjun Du, Mats Andersson, Sven Andersson
To investigate the influence of ethanol blending in diesel fuel on the spray and spray combustion characteristics, experiments were carried out in an optically accessed high-pressure / high-temperature spray chamber under non-evaporating, evaporating and combusting conditions. Three different fuels were investigated in this study: (1) Diesel, a conventional diesel fuel; (2) E10, 10% ethanol and 2% emulsion additive blended to diesel and (3) E20, 20% ethanol and 2% emulsion additive blended to diesel. Gas conditions were kept at a constant gas density 24.3 kg/m3 under non-evaporating (30 ºC, 21.1 bar), evaporating (350 ºC, 43.4 bar), lower combusting temperature (550 ºC, 57.3 bar) and higher combusting temperature (600 ºC, 60 bar) conditions. A single-hole injector with a nozzle diameter of 0.14 mm was used and injection pressure was kept constant at 1350 bar. High-speed shadowgraph image sequences were captured to measure spray penetration and spray cone angle. OH-chemiluminescence images and soot luminescence images were acquired using intensified CCD cameras to measure lift-off length and to observe overall volume of soot formation.
Technical Paper
2014-10-13
Yanfei Li, Hengjie Guo, Jian-Xin Wang, Hongming Xu
In this paper, the spray characteristics of gasoline, butanol and the blends have been investigated using a GDI multi-hole injector. The tests are carried out in constant volume vessels and the variables include injection pressure, ambient pressure and fuel temperature. A Photron SAX2 high-speed camera is used to record the evolution of macroscopic spray penetration and cone angle, and a set of Phase Doppler Particle Analyzer (PDPA) is used to study the microscopic characteristics of the sprays, including the droplet size and velocity evolution. Further, a close-up optical path was used in order to obtain the straightforward views on the spray atomization process. Finally, the dimensionless analysis is conducted to account for the difference between the two fuels.
Technical Paper
2014-10-13
Masaki Kuribayashi, Yuta Mizutani, Yutaro Ishizuka, Natsuki Taki, Tetsuya Aizawa
For better understanding of soot formation and oxidation processes in diesel combustion, effects of ambient oxygen concentration on in-flame diesel soot particle properties including concentration, size, number density and morphology were investigated via simultaneous LII (Laser Induced Incandescence) / LS (Laser Scattering) imaging techniques and TEM (Transmission Electron Microscopy) analysis. An analysis of LII and LS images yielded 2-dimensional distribution images of concentration, size and number density of soot particles in diesel spray flame, based on a practical assumption that LII and LS signals are proportional to the soot particle size to the power of 3 and 6, respectively. The laser measurements and TEM analysis results of soot particles directly sampled in the diesel spray flame showed a consistent general trend that in the case of 21% ambient O2 concentration soot is formed earlier in the upstream region and disappears earlier due to faster oxidation, while in the case of 15% ambient O2 concentration, soot is formed later in more downstream region and disappears more slowly.
Technical Paper
2014-10-13
Kenan Muric, Ola Stenlaas, Per Tunestal, Bengt Johansson
In the last couple of decades, countries have enacted new laws concerning environmental pollution caused by heavy-duty commercial and passenger vehicles. This is done mainly in an effort to reduce smog and health impacts caused by the different pollutions. One of the legislated pollutions, among a wide range of regulated pollutions, is nitrogen oxides (commonly abbreviated as NOx). The SCR (Selective Catalytic Reduction) was introduced in the automotive industry to reduce NOx emissions leaving the vehicle. The basic idea is to inject a urea solution (AdBlue™) in the exhaust gas before the gas enters the catalyst. The optimal working temperature for the catalyst is somewhere in the range of 300 to 400 °C. For the reactions to occur without a catalyst, the gas temperature has to be at least 800 °C. These temperatures only occur in the engine cylinder itself, during and after the combustion. In this paper a study is presented where a second injector is installed in a Scania D13 cylinder head for urea injection purposes.
Technical Paper
2014-10-13
Achinta Varna, Konstantinos Boulouchos, Alexander Spiteri, Panayotis Dimopoulos Eggenschwiler, Yuri M. Wright
Simulations for a pressure-assisted multi-stream injector designed for urea-dosing in a selective catalytic reduction (SCR) exhaust gas system have been carried out and compared to measurements taken in an optically accessible high-fidelity flow test rig. The experimental data comprises four different combinations of mass flow rate and temperature for the gas stream with unchanged injection parameters for the spray. First, a parametric study is carried out to determine the importance of various spray sub-models, including atomization, spray-wall interaction, buoyancy as well as droplet coalescence. Optimal parameters are determined using experimental data for one reference operating condition. The model is subsequently applied to all operating conditions with unaltered parameters and validated by means of the measured droplet velocity fields, droplet diameter distributions and spray-tip propagations which have been characterized by means of Particle Image Velocimetry (PIV), Phase Doppler Anemometry (PDA) and shadow imaging.
Training / Education
2014-10-06
As diesel engines become more popular, a fundamental knowledge of diesel technology is critical for anyone involved in the diesel engine support industry. This course will explain the fundamental technology of diesel engines starting with a short but thorough introduction of the diesel combustion cycle, and continue with aspects of engine design, emission control design, and more. An overview of developing technologies for the future with a comprehensive section on exhaust aftertreatment is also included. The text, Diesel Emissions and Their Control, authored by Magdi Khair and W. Addy Majewski is included with the seminar.
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