MACROSCOPIC SPRAY BEHAVIOR AND ATOMIZATION CHARACTERISTICS OF R407C INJECTION

2012 ◽  
Vol 20 (03) ◽  
pp. 1250009 ◽  
Author(s):  
CHUL WOO ROH ◽  
MIN SOO KIM
Keyword(s):  
Image Processing ◽  
Ambient Pressure ◽  
Cone Angle ◽  
High Pressure Chamber ◽  
Qualitative Properties ◽  
Contour Map ◽  
Visualization System ◽  
Start Of Injection ◽  
Spray Visualization ◽  
Atomization Characteristics

This study investigated the spray behavior and atomization characteristics of refrigerant R407C injection in a high pressure chamber under various ambient pressure conditions using a spray visualization system and image processing methods. In order to observe the spray behavior of refrigerant R407C, the spray images were analyzed in time series after the start of injection. From images of spraying features, spray characteristics, for example, the spray tip penetration and cone angle were investigated by using the contour map of the light intensity levels. By using these processes, qualitative properties of refrigerant, when it is discharged from the valve, were quantified.

Effects of Fuel Nozzle Condition on Gas Turbine Combustion Chamber Exit Temperature Distributions

2010 ◽  
Author(s):  
Kristen Bishop ◽  
William Allan
Keyword(s):  
Combustion Chamber ◽  
Ambient Pressure ◽  
Cone Angle ◽  
Operating Conditions ◽  
Spray Cone Angle ◽  
Mixing Processes ◽  
Spray Cone ◽  
Temperature Distributions ◽  
Fuel Nozzle ◽  
Exit Temperature

The effects of fuel nozzle condition on the temperature distributions experienced by the nozzle guide vanes have been investigated using an optical patternator. Average spray cone angle, symmetry, and fuel streaks were quantified. An ambient pressure and temperature combustion chamber test rig was used to capture exit temperature distributions and to determine the pattern factor. The rig tests matched representative engine operating conditions by matching Mach number, equivalence ratio, and fuel droplet size. It was observed that very small deviations (± 10° in spray cone angle) from a nominal distribution in the fuel nozzle spray pattern correlated to increases in pattern factor, apparently due to a degradation of mixing processes, which created larger regions of very high temperature core flow and smaller regions of cooler temperatures within the combustion chamber exit plane. The spray cone angle had the most measureable influence while the effects of spray roundness and streak intensity had slightly less influence. Comparisons were made with published studies conducted on the combustion chamber geometry, and recommendations were made for fuel nozzle inspections.

Comparison Between a Center-Mounted and a Side-Mounted Injector for Gasoline Applications: A Computational Study

2020 ◽  
Author(s):  
Lorenzo Nocivelli ◽  
Anqi Zhang ◽  
Brandon A. Sforzo ◽  
Aniket Tekawade ◽  
Alexander K. Voice ◽  
...  
Keyword(s):  
Best Practice ◽  
Computational Study ◽  
Ambient Pressure ◽  
Near Field ◽  
Cone Angle ◽  
Injection Pressure ◽  
Operating Conditions ◽  
Gasoline Direct Injection ◽  
X Ray ◽  
Fuel Density

Abstract The differences between a center-mounted and a side-mounted injector for gasoline direct injection (GDI) applications are analyzed through computational fluid dynamics (CFD). The Engine Combustion Network’s (ECN) axisymmetric 8-hole Spray G injector is compared to a 6-hole injector designed to be side-mounted in an engine. Nozzle-flow simulations are carried out with the commercial CFD software CONVERGE, injecting Euro 5 certification gasoline into a constant volume chamber. Low-load operating conditions are targeted, setting the injection pressure at 50 bar and the ambient pressure to be representative of very early pilot injections. The phase change is handled with the Homogeneous Relaxation Model (HRM), which is assessed and adapted to gasoline flash-boiling conditions. The simulation domains are generated leveraging real injector internal geometries obtained by micron-resolution X-ray tomographic measurements, which introduce manufacturing tolerances and surface roughness in the computational study. Steady needle lift conditions are analyzed. The near-field fuel density distributions and plume morphologies are evaluated, validated and compared to X-ray radiography measurements. A computational best practice is defined and single plume characteristics and variability trends are highlighted as functions of the geometry of the orifices. The plume-plume interaction dynamics are identified and assessed, underlining differences from center- to side-mounted injectors at strong flashing conditions. The obtained numerical framework allows the identification of near-nozzle injection characteristics such as single plume direction, cone angle, spray initial velocity and spatial fuel density distribution. The presented results represent a unique dataset for the initialization of more-affordable Lagrangian spray models, which differentiate the behavior of side-mounted and center-mounted injectors.

scholarly journals Spray and atomization characteristics of gas-centered swirl coaxial injectors

2016 ◽  
Vol 9 (2) ◽  
pp. 127-140 ◽  
Author(s):  
Rahul Anand ◽  
PR Ajayalal ◽  
Vikash Kumar ◽  
A Salih ◽  
K Nandakumar
Keyword(s):  
Rocket Engine ◽  
Cone Angle ◽  
Spray Angle ◽  
Rocket Engines ◽  
Sauter Mean Diameter ◽  
Swirl Number ◽  
Spray Cone ◽  
Mean Diameter ◽  
Atomization Characteristics ◽  
Coaxial Injector

To achieve uniform and efficient combustion in a rocket engine, a fine uniform spray is needed. The same is achieved by designing an injector with good atomization characteristics. Gas-centered swirl coaxial (GCSC) injector elements have been preferred recently in liquid rocket engines because of an inherent capability to dampen the pressure oscillations in the thrust chamber. The gas-centered swirl coaxial injector chosen for this study is proposed to be used in a semi-cryogenic rocket engine operating with oxidizer rich hot exhaust gases from the pre-burner and liquid kerosene as fuel. In this paper, nine different configurations of gas-centered swirl coaxial injector, sorted out by studying the spray angle and coefficient of discharge with swirl number varying from 9 to 20 and recess ratio of 0.5, 1, and 1.5 are investigated for their atomization characteristics. Spray uniformity, spray cone angle, and droplet size in terms of Sauter mean diameter and mass median diameter are studied at various momentum flux ratios for all configurations. Sauter mean diameter is almost independent of recess ratio, whereas cone angle was inversely proportional to the recess ratio. A finer atomization was observed for injectors of high swirl number but the pressure drop also increased to achieve the same flow rate. An injector of medium swirl number and recess ratio of 1.5 is deemed most fit for above-mentioned application.

Evaporation characterization of fuel spray impinging on a flat wall by laser-based measurement

2016 ◽  
Vol 18 (8) ◽  
pp. 776-784 ◽  
Author(s):  
Yuyin Zhang ◽  
Shiyan Li ◽  
Wenyuan Qi ◽  
Keiya Nishida
Keyword(s):  
Power Law ◽  
Ambient Pressure ◽  
Measurement Data ◽  
Injection System ◽  
Fuel Spray ◽  
Fuel Vapor ◽  
Flat Wall ◽  
Common Rail Injection System ◽  
Start Of Injection ◽  
Power Law Function

It is of interest for engine combustion modeling to quantify the evaporation behaviors of fuel spray impinging on a wall as the fuel atomization, evaporation, and mixing with oxygen in the combustion chamber usually dominate the subsequent combustion processes. In this study, the vapor and liquid mass distributions in diesel-like fuel sprays were quantified using the ultraviolet-visible laser absorption scattering imaging technique. The sprays were injected from a single-hole nozzle with a common-rail injection system and impinged on a flat wall at an ambient pressure of 4 MPa and an ambient temperature of 833 K. The mass of the total fuel vapor, the spray volume covered by the vapor phase, and the air mass entrained into the spray were characterized. The results indicate that the time evolution of these parameters until shortly after the end of injection can be expressed by a power-law function, Yi =  ki· ts1.5, where Yi represents the parameter like vapor mass and so on, ts is the time after start of injection, and ki is the coefficient corresponding to Yi. The physics behind this power-law function was analyzed and discussed based on the theory of atomization and evaporation, and verified using measurement data obtained under different conditions of injection quantity.

Experimental investigations of kerosene sprays in pressurized evaporating environments

2018 ◽  
Vol 233 (3) ◽  
pp. 413-427 ◽  
Author(s):  
Tao Liu ◽  
Wei Fu ◽  
Bolun Yi ◽  
Lanbo Song ◽  
Qizhao Lin ◽  
...  
Keyword(s):  
Experimental Data ◽  
Ambient Temperature ◽  
High Speed ◽  
Ambient Pressure ◽  
Cone Angle ◽  
Experimental Investigations ◽  
Spray Cone Angle ◽  
Spray Cone ◽  
Ambient Temperatures ◽  
Performance And Emissions

Experiments of kerosene spray with single-hole solenoid injector in the pressurized nonevaporating and evaporating environments, in which the ambient pressure ranges from 1.4 MPa to 4.8 MPa and the ambient temperature includes 300 K, 343 K, and 423 K, are carried out with high-speed Schlieren photography to investigate the breakup regimes and the macro-characteristics like penetration, projected spray area, and spray cone angle. Repetitive experiments are conducted to analyze the penetration repeatability. The comparison between the experimental penetrations and the predicted ones by the existing correlations reveals that the deviations between the experimental data and the predictions rise as the ambient temperature rises. Therefore, a new modified correlation is proposed to predict the penetration of kerosene spray in the nonevaporating and evaporating environments, which fits the experimental data better than the existing correlations. The breakup regimes in primary breakup and secondary breakup are discussed respectively. The projected spray area is analyzed under different ambient pressures at different ambient temperatures. Finally, it is found that the spray cone angle remains almost the same under different ambient pressures after it reduces sharply before 0.5 ms. The macro-characteristics discussed in the present study are important for the performance and emissions of aeronautical engines or diesel engines fuelled by kerosene as a substitution.

Spray Performance of Alternative Jet Fuel Based Nanofuels at High-Ambient Conditions

2018 ◽  
Author(s):  
Mohamed Soltan ◽  
Buthaina Al Abdulla ◽  
AlReem Al Dosari ◽  
Kumaran Kannaiyan ◽  
Reza Sadr
Keyword(s):  
Ambient Pressure ◽  
Cone Angle ◽  
Jet Fuel ◽  
Liquid Sheet ◽  
Ambient Conditions ◽  
Spray Characteristics ◽  
Atomization Process ◽  
Spray Cone Angle ◽  
Spray Cone ◽  
Sheet Breakup

Dispersion of nanoparticles in pure fuels alters their key fuel physical properties, which could affect their atomization process, and in turn, their combustion and emission characteristics in a combustion chamber. Therefore, it is essential to have a thorough knowledge of the atomization characteristics of nanofuels (nanoparticles dispersed in pure fuels) to better understand their latter processes. This serves as the motivation for the present work, which attempts to gain a good understanding of the atomization process of the alternative, gas-to-liquid (GTL), jet fuel based nanofuels. The macroscopic spray characteristics such as spray cone angle, liquid sheet breakup, and liquid sheet velocity are determined by employing shadowgraph imaging technique. The effect of nanoparticles weight concentration and ambient pressures on the spray characteristics are investigated in a high pressure-high temperature constant volume spray rig. To this end, a pressure swirl nozzle with an exit diameter of 0.8 mm is used to atomize the fuels. The macroscopic spray results demonstrate that the nanoparticles dispersion at low concentrations affect the near nozzle region. The spray liquid sheet breakup distance is reduced by the presence of nanoparticle due to the early onset of disruption in the liquid sheet. Consequently, the liquid sheet velocity in that spray region is higher for nanofuels when compared to that of pure fuels. Also, the ambient pressure has a significant effect on the spray features as reported in the literature.

Pressure-Scaling of Pressure-Swirl Atomizer Cone Angles

2006 ◽  
Author(s):  
D. R. Guildenbecher ◽  
R. R. Rachedi ◽  
P. E. Sojka
Keyword(s):  
Pressure Drop ◽  
Ambient Pressure ◽  
Cone Angle ◽  
Subsequent Increase ◽  
Gas Entrainment ◽  
A Value ◽  
Swirl Atomizer ◽  
Pressure Swirl ◽  
Pressure Swirl Atomizer ◽  
Measure Cone

An experimental investigation was conducted to study the effects of increased ambient pressure (up to 6.89 MPa) and increased nozzle pressure drop (up to 2.8 MPa) on the cone angles for sprays produced by pressure-swirl atomizers having varying amounts of initial swirl. This study extends the classical results of DeCorso and Kemeny [1]. Shadow photography was used to measure cone angles at x/D0=10, 20, 40, and 60. Our lower pressure results for atomizer swirl numbers of 0.50 and 0.25 are consistent with those of DeCorso and Kemeny [1], who observed a decrease in cone angle with an increase in a pressure drop-ambient density product until a minimum cone angle was reached at ΔPρair1.6~200. Results for atomizers having higher swirl numbers do not match the DeCorso and Kemeny [1] results as well, suggesting that their correlation be used with caution. Another key finding is that an increase in ΔPρair1.6 to a value of 1000 leads to continued decreases in cone angle, but that a subsequent increase to 4000 has little effect on cone angle. Finally, there was little influence of atomizer pressure drop on cone angle, in contrast to findings of previous workers. These effects are hypothesized to be due to gas entrainment.

Atomization Characteristics of Jatropha-Derived Alternative Aviation Fuels From Aircraft Engine Injector

2017 ◽  
Author(s):  
Ramachandran Sakthikumar ◽  
Deivandren Sivakumar ◽  
B. N. Raghunandan ◽  
John T. C. Hu
Keyword(s):  
Size Distribution ◽  
Drop Size ◽  
Cone Angle ◽  
Fuel Spray ◽  
Jet Fuels ◽  
Spray Characteristics ◽  
Spray Cone Angle ◽  
Spray Cone ◽  
Atmospheric Air ◽  
Atomization Characteristics

Search for potential alternative jet fuels is intensified in recent years to meet stringent environmental regulations imposed to tackle degraded air quality caused by fossil fuel combustion. The present study describes atomization characteristics of blends of jatropha-derived biofuel with conventional aviation kerosene (Jet A-1) discharging into ambient atmospheric air from a dual-orifice atomizer used in aircraft engines. The biofuel blends are characterized in detail and meet current ASTM D7566 specifications. The experiments are conducted by discharging fuel spray into quiescent atmospheric air in a fuel spray booth to measure spray characteristics such as fuel discharge behavior, spray cone angle, drop size distribution and spray patternation at six different flow conditions. The characteristics of spray cone angle are obtained by capturing images of spray and the measurements of spray drop size distribution are obtained using laser diffraction particle analyzer (LDPA). A mechanical patternator system comprising 144 measurement cells is used to deduce spray patternation at different location from the injector exit. A systematic comparison on the atomization characteristics between the sprays of biofuel blends and the 100% Jet A-1 is presented. The measured spray characteristics of jatropha-derived alternative jet fuels follow the trends obtained for Jet A-1 sprays satisfactorily both in qualitative and quantitative terms.

Combustion Analysis of Twisting-Blade Piston Diesel Engine Fuelled With Karanja Bio-Diesel

2013 ◽  
Author(s):  
Chandrashekarapur Ramachandraih Rajashekar ◽  
Tumkur Krishnamurthy Chandrasekhar ◽  
Tejendra Prasad ◽  
Chelur Rangalppa Kemparaju ◽  
Chebiyyam Uma Shankar
Keyword(s):  
Diesel Engine ◽  
Cone Angle ◽  
High Viscosity ◽  
Combustible Mixture ◽  
Emission Characteristics ◽  
Combustion Analysis ◽  
Piston Engine ◽  
Compression Stroke ◽  
Piston Crown ◽  
Atomization Characteristics

Bio-diesels have very poor atomization characteristics, due to decreased cone angle because of high viscosity and low volatility. Innovativeness is required to use the bio-diesel as efficient vehicular fuel. This paper presents the effect of piston geometry on combustion and emission characteristics of Karanja bio-diesel fuelled C.I.Engine. The piston crown has been modified into twisting blade combustion chamber. Three blades are made to twist through an angle of 60o in the piston crown at the end of compression stroke to induce turbulence to improve the combustibility of combustible mixture. In the present work the combustion and emission characteristics of twisting blade piston fuelled with Karanja bio-diesel have been studied and compared with standard piston engine.

Research of the Atomization Characteristics of Low Pollution Air Blast Nozzle

2013 ◽  
Vol 655-657 ◽  
pp. 133-136
Author(s):  
Kai Liu
Keyword(s):  
Particle Size ◽  
Cone Angle ◽  
Combustion Efficiency ◽  
Outlet Temperature ◽  
Design Development ◽  
Spray Cone Angle ◽  
Spray Cone ◽  
Group Design ◽  
Atomization Characteristics ◽  
Reliable Basis

Atomization characteristic has great impact about combustion efficiency, ignition performance, and outlet temperature field of combustor. Obtained atomization characteristic about spray particle size and spray cone angle using LDV/PDPA system and the relevant software. The results indicated: particle size decrease rapidly with increasing air and tends to stabilize, Spray cone angle does not change with the air pressure. These experimental data have provided reliable basis for the nozzle group design, development and operation.

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