Influence of Elevated Fuel Temperatures on the Spray Characteristics of Gasoline - Ethanol Blends

2021 ◽  
Author(s):  
Niranjan Miganakallu ◽  
Ashwin Karthik Purushothaman ◽  
William R. Atkinson ◽  
Nathan Peters ◽  
Tadeu Miguel Malago Amaral ◽  
...  
Keyword(s):  
High Speed ◽  
Injection Pressure ◽  
Gasoline Direct Injection ◽  
Spray Angle ◽  
Fuel Injector ◽  
Ambient Conditions ◽  
Spray Characteristics ◽  
Fuel Blends ◽  
Flash Boiling ◽  
Ethanol Blends

Abstract In this study, the effect of elevated fuel temperatures on the spray characteristics of gasoline-ethanol blends were studied in an optically accessible constant volume spray and combustion vessel. MAHLE SmartHeat® is a fuel heater located directly upstream of the fuel injector. High speed images of the spray injected from a six-hole gasoline direct injection injector typical of a side-injection engine were captured with shadowgraph imaging technique. Two fuel blends, gasoline with 10% ethanol (E10) and 85% ethanol (E85) were investigated at ambient conditions of 1 bar, 45°C and 4 bar, 180°C respectively at an injection pressure of 100 bar. Fuel temperatures were varied from 75 to 250°C. A comparison of the near nozzle and the global spray characteristics was made for the two fuels at those temperatures. Results showed that flash boiling leads to two primary effects for the two fuel blends: (i) an appreciable increase in spray angle near the exit of the nozzle followed by (ii) a decrease in spray angle downstream of the nozzle due to the interaction of the plumes and the collapsing of the spray. Furthermore, for both fuel blends, upon flash boiling, entrainment and mixing were reduced downstream of the nozzle because of the collapse of the spray. To reduce this effect, nozzle orientations and geometries should be modified.

scholarly journals Impact of gasoline direct injection fuel injector hole geometry on spray characteristics under flash boiling and ambient conditions

Fuel ◽  
2019 ◽  
Vol 241 ◽  
pp. 71-82 ◽  
Author(s):  
Changzhao Jiang ◽  
Matthew C. Parker ◽  
Jerome Helie ◽  
Adrian Spencer ◽  
Colin P. Garner ◽  
...  
Keyword(s):  
Direct Injection ◽  
Gasoline Direct Injection ◽  
Fuel Injector ◽  
Ambient Conditions ◽  
Spray Characteristics ◽  
Hole Geometry ◽  
Flash Boiling

Effect of ultra-high injection pressure up to 50 MPa on macroscopic spray characteristics of a multi-hole gasoline direct injection injector fueled with ethanol

2017 ◽  
Vol 232 (8) ◽  
pp. 1092-1104 ◽  
Author(s):  
Xiang Li ◽  
Yi-qiang Pei ◽  
Jing Qin ◽  
Dan Zhang ◽  
Kun Wang ◽  
...  
Keyword(s):  
High Speed ◽  
Direct Injection ◽  
Cone Angle ◽  
Injection Pressure ◽  
Fuel Mixture ◽  
Gasoline Direct Injection ◽  
Spray Characteristics ◽  
High Injection ◽  
High Injection Pressure ◽  
Wall Impingement

This research systematically studied the effect of injection pressure on macroscopic spray characteristics of a five-hole gasoline direct injection (GDI) injector fueled with ethanol, especially under ultra-high injection pressure up to 50 MPa. The front and side views of sprays were photographed by the schlieren method using a high-speed camera. Various parameters, including spray development stages, cone angle, penetration, area and irregular ratio, were fully analyzed to evaluate macroscopic characteristics of the whole spray and spray core with varying injection pressure. The results demonstrated that the effect of ultra-high injection pressure on macroscopic spray characteristics was significant. As injection pressure increased from 10 MPa to 50 MPa, the occurrence time of branch-like structure decreased; the cone angle increased little; the area increased significantly; the area ratio dropped by 6.4 and 5.8 percentage points on average for the front view and side view spray, respectively. There was a significant increase in the trend for penetration as the injection pressure rose from 10 MPa to 30 MPa. However, this trend became weak when the injection pressure further increased. The penetration ratio under ultra-high injection pressure was slightly higher than it was under 10 or 20 MPa. Ultra-high injection pressure would not obviously raise the possibility of spray/wall impingement, but led to the impingement quantity increasing to some extent. Increasing injection pressure could enhance the vortex scale, finally resulting in better air/fuel mixing quality. Ultra-high injection pressure was a potential way to improve air/fuel mixture homogeneity for a GDI injector fueled with ethanol.

Characterization of Gasoline and E85 Direct Injection Sprays in a Constant Volume Vessel Under Late Cycle Engine Conditions

2011 ◽  
Author(s):  
Christopher J. Morgan ◽  
Rajat Arora ◽  
Jaclyn E. Nesbitt ◽  
Seong-Young Lee ◽  
Jeffrey D. Naber
Keyword(s):  
High Pressure ◽  
Charge Density ◽  
Injection Pressure ◽  
Mie Scattering ◽  
Constant Volume ◽  
Spray Angle ◽  
Injection Timing ◽  
Fuel Injector ◽  
Ambient Conditions ◽  
Fuel Temperature

Spray characteristics of a high pressure gasoline direct injector were studied in a constant volume optical combustion vessel over a range of charge gas composition, pressure and temperature conditions for gasoline and E85. The fuel injector was a Bosch GDI injector, with fuel delivery provided through a high pressure accumulator supply system. The conditions were selected to match those for late injection timing during the compression stroke. To simulate the in-cylinder conditions, the combustion chamber temperatures and pressures were varied from 30°C to 305°C and from 1.8 bar to 9.2 bar respectively. Injection pressure was held constant at 30 bar. Injector and thus initial fuel temperature was controlled independently of the ambient conditions at 50°C. Simultaneous images were taken using Schlieren, laser luminescence and Mie scattering diagnostics. It was found that penetration and spray angle are primarily dependent on charge density, and vaporization is dependent on both charge density and charge temperature. The gasoline sprays are shown to have increased vaporization and higher penetration in comparison to E85.

scholarly journals Liquid Propane Injection in Flash-Boiling Conditions

Energies ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 6257
Author(s):  
Łukasz Jan Kapusta ◽  
Jakub Bachanek ◽  
Changzhao Jiang ◽  
Jakub Piaszyk ◽  
Hongming Xu ◽  
...  
Keyword(s):  
High Speed ◽  
Saturation Pressure ◽  
Injection Pressure ◽  
Spray Angle ◽  
Liquid Propane ◽  
Spray Tip Penetration ◽  
Commercial Gasoline ◽  
Flash Boiling ◽  
Set Up ◽  
The Impact

This study aimed to investigate the influence of flash-boiling conditions on liquid propane sprays formed by a multi-hole injector at various injection pressures. The focus was on spray structures, which were analysed qualitatively and quantitatively by means of spray-tip penetration and global spray angle. The effect of flash boiling was evaluated in terms of trends observed for subcooled conditions. Propane was injected by a commercial gasoline direct injector into a constant volume vessel filled with nitrogen at pressures from 0.1 MPa up to 6 MPa. The temperature of the injected liquid was kept constant. The evolution of the spray penetration was observed by a high-speed camera with a Schlieren set-up. The obtained results provided information on the spray evolution in both regimes, above and below the saturation pressure of the propane. Based on the experimental results, an attempt to calibrate a simulation model has been made. The main advantage of the study is that the effects of injection pressure on the formation of propane sprays were investigated for both subcooled and flash-boiling conditions. Moreover, the impact of the changing viscosity and surface tension was limited, as the temperature of the injected liquid was kept at the same level. The results showed that despite very different spray behaviours in the subcooled and flash-boiling regimes, leading to different spray structures and a spray collapse for strong flash boiling, the influence of injection pressure on propane sprays in terms of spray-tip penetration and spray angle is very similar for both conditions, subcooled and flash boiling. As for the numerical model, there were no single model settings to simulate the flashing sprays properly. Moreover, the spray collapse was not represented very well, making the simulation set-up more suitable for less superheated sprays.

Experimental Study of the Spray Characteristics of n-Butanol/Diesel Blends

2014 ◽  
Vol 960-961 ◽  
pp. 1394-1399
Author(s):  
Jian Wu ◽  
Li Li Zhu ◽  
Zhan Cheng Wang ◽  
Bin Xu ◽  
Hong Ming Wang
Keyword(s):  
High Speed ◽  
Ambient Pressure ◽  
Cone Angle ◽  
Injection Pressure ◽  
Spray Characteristics ◽  
Spray Cone Angle ◽  
Spray Cone ◽  
Spray Penetration ◽  
Fuel Blends ◽  
Area Increase

we studied the spray characteristics of n-butanol/diesel fuel blends using a high-speed camera and schlieren system, and analyzed the effect of different fuels, ambient pressure and injection pressure conditions on the spray penetration, spray cone angle, spray area, et al. The results showed that, at the same injection pressure, as the increase of ambient pressure, the spray cone angle of the same volume of fuel increases gradually, the spray penetration and the spray area decreases; under the same ambient pressure, the spray penetration, spray cone angle and spray area increase gradually with the increasing injection pressure, but when the injection pressure increases enough, the parameters are roughly the same; and the parameters basically all increase with the adding of n-butanol.

scholarly journals Experimental Study of Spray Characteristics of Kerosene-Ethanol Blends from a Pressure-Swirl Nozzle

2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Tao Zhang ◽  
Bo Dong ◽  
Xun Zhou ◽  
Linan Guan ◽  
Weizhong Li ◽  
...  
Keyword(s):  
Discharge Coefficient ◽  
Cone Angle ◽  
Injection Pressure ◽  
Spray Characteristics ◽  
Spray Cone Angle ◽  
Spray Cone ◽  
Breakup Length ◽  
Ethanol Blends ◽  
Pressure Swirl ◽  
Spray Velocity

Partial replacement of kerosene by ethanol in a gas turbine is regarded as a good way to improve the spray quality and reduce the fossil energy consumption. The present work is aimed at studying the spray characteristics of kerosene-ethanol blends discharging from a pressure-swirl nozzle. The spray cone angle, discharge coefficient, breakup length, and velocity distribution are obtained by particle image velocimetry, while droplet size is acquired by particle/droplet imaging analysis. Kerosene, E10 (10% ethanol, 90% kerosene), E20 (20% ethanol, 80% kerosene), and E30 (30% ethanol, 70% kerosene) have been considered under the injection pressure of 0.1–1 MPa. The results show that as injection pressure is increased, the discharge coefficient and breakup length decrease, while the spray cone angle, drop size, and spray velocity increase. Meanwhile, the drop size decreases and the spray velocity increases with ethanol concentration when the injection pressure is lower than 0.8 MPa. However, the spray characteristics are not affected obviously by the ethanol concentration when the injection pressure exceeds 0.8 MPa. A relation to breakup length for kerosene-ethanol blends is obtained. The findings demonstrate that the adding of ethanol into kerosene can promote atomization performance.

scholarly journals High Speed Shadowgraphy of Transparent Nozzles as an Evaluation Tool for In-Nozzle Cavitation Behavior of GDI Injectors

2017 ◽  
Author(s):  
Dmitrii Mamaikin ◽  
Tobias Knorsch ◽  
Philipp Rogler ◽  
Philippe Leick ◽  
Michael Wensing
Keyword(s):  
High Speed ◽  
Gasoline Engine ◽  
Transient Flow ◽  
Direct Injection ◽  
Ambient Air ◽  
Gasoline Direct Injection ◽  
Fuel Injector ◽  
Evaluation Tool ◽  
Long Distance ◽  
Cavitation Behavior

Gasoline Direct Injection (GDI) systems have become a rapidly developing technology taking up a considerableand rapidly growing share in the Gasoline Engine market due to the thermodynamic advantages of direct injection. The process of spray formation and propagation from a fuel injector is very crucial in optimizing the air-fuel mixture of DI engines. Previous studies have shown that the presence of some cavitation in high-pressure fuel nozzles can lead to better atomization of the fluid. However, under some very specific circumstances, high levels of cavitation can also delay the atomization process; spray stabilization due to hydraulic flip is the most well-known example. Therefore, a better understanding of cavitation behavior is of vital importance for further optimization of next generation fuel injectors.In contrast to the abundance of investigations conducted on the inner flow and cavitation patterns of diesel injectors, corresponding in-depth research on the inner flow of gasoline direct-injection nozzles is still relatively scarce. In this study, the results of an experiment performed on real-size GDI injector nozzles made of acrylic glass are presented. The inner flow of the nozzle is visualized using a high-power pulsed laser, a long-distance microscope and a high- speed camera. The ambiguity of dark areas on the images, which may represent cavitation regions as well as ambient air drawn into the nozzle holes, is resolved by injecting the fuel both into a fuel or gas filled environment. In addition, the influence of backpressure on the transient flow characteristics of the internal flow is investigated. In good agreement with observations made in previous studies, higher backpressure levels decrease the amount of cavitation inside the nozzles. Due to the high temporal and spatial resolution of the experiment, the transient cavitation behavior during the opening, quasi-steady and closing phases of the injector needle motion can be analyzed. For example, it is found that cavitation patterns oscillate with a characteristic frequency that depends on the backpressure. The link between cavitation and air drawn into the nozzle at the beginning of injection is alsorevealed.DOI: http://dx.doi.org/10.4995/ILASS2017.2017.4639

scholarly journals Flashboiling atomization in nozzles for GDI engines

2017 ◽  
Author(s):  
Sebastian Bornschlegel ◽  
Chris Conrad ◽  
Lisa Eichhorn ◽  
Michael Wensing
Keyword(s):  
Penetration Depth ◽  
High Speed ◽  
Aerodynamic Drag ◽  
Ambient Pressure ◽  
Rapid Expansion ◽  
Gasoline Direct Injection ◽  
Coolant Temperature ◽  
Concentrated Mass ◽  
Flash Boiling ◽  
Gdi Engines

Flashboiling denotes the phenomenon of rapid evaporation and atomization at nozzles, which occurs when fluidsare injected into ambient pressure below their own vapor pressure. It happens in gasoline direct injection (GDI) engines at low loads, when the cylinder pressure is low during injection due to the closed throttle valve. The fuel temperature at the same time approaches cylinder head coolant temperature due to the longer dwell time of the fuel inside the injector. Flash boiling is mainly beneficial for atomization quality, since it produces small droplet sizes and relative broad and homogenous droplet distributions within the spray. Coherently, the penetration depth normally decreases due to the increased aerodynamic drag. Therefore the thermal properties of injectors are often designed to reach flash boiling conditions as early as possible. At the same time, flash boiling significantly increases the risk of undesired spray collapsing. In this case, neighbouring jets converge and form a single jet. Due to the now concentrated mass, penetration depth is enhanced again and can lead to liner or piston wetting in addition to the overall diminished mixture formation.In order to understand the underlying physics, it is important to study the occurring phenomena flashboiling and jet-to-jet interacting i.e. spray collapsing separately. To this end, single hole injectors are built up to allow for an isolated investigation of flashboiling. The rapid expansion at the nozzle outlet is visualized with a microscopic high speed setup and the forces that lead to the characteristic spray expansion are discussed. Moreover, the results on the macroscopic spray in terms of penetration, cone angles and vapor phase are shown with a high speed Schlieren setup. Resulting droplet diameters and velocities are measured using LDA/PDA.As a result, we find a comprehensive picture of flash boiling. The underlying physics can be described and discussed for the specific case of high pressure injection at engine relevant nozzle geometries and conditions, but independently from neighbouring jets. These findings provide the basis to understand and investigate flashboilingand jet-to-jet interaction as distinct, but interacting subjects rather than a combined phenomenon.DOI: http://dx.doi.org/10.4995/ILASS2017.2017.4750 

Microscopic Spray Characteristics of Biodiesels Derived From Karanja, Jatropha, and Waste Cooking Oils

2020 ◽  
Vol 142 (12) ◽  
Author(s):  
Chetankumar Patel ◽  
Joonsik Hwang ◽  
Choongsik Bae ◽  
Rashmi A. Agarwal ◽  
Avinash Kumar Agarwal
Keyword(s):  
Fuel Injection ◽  
Direct Injection ◽  
Injection Pressure ◽  
Axial Direction ◽  
Waste Cooking Oil ◽  
Injection System ◽  
Ambient Atmosphere ◽  
Ambient Conditions ◽  
Spray Characteristics ◽  
Spray Droplets

Abstract This study aims to assess the microscopic characteristics of Jatropha, Karanja, and Waste cooking oil-based biodiesels vis-a-vis conventional diesel under different ambient conditions in order to understand the in-cylinder processes, while using biodiesels produced from different feedstocks in the compression ignition engines. All test-fuels were injected in ambient atmosphere using a common-rail direct injection (CRDI) fuel injection system at a fuel injection pressure (FIP) of 40 MPa. Microscopic spray characteristics were measured using phase Doppler interferometer (PDI) in the axial direction of the spray at a distance of 60–90 mm downstream of the nozzle and at 0 to 3-mm distance from the central axis in the radial direction. All biodiesels exhibited relatively larger Sauter mean diameter (SMD) of the spray droplets and higher droplet velocities compared to baseline mineral diesel, possibly due to relatively higher fuel viscosity and surface tension of biodiesels. It was also observed that SMD of the spray droplets decreased with increasing distance in the radial and axial directions and the same trend was observed for all test-fuels.

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