scholarly journals Effect of the two-phase hybrid mode of effervescent atomizer on the atomization characteristics

Open Physics ◽  
2019 ◽  
Vol 17 (1) ◽  
pp. 960-965
Author(s):  
Liansheng Liu ◽  
Na Pei ◽  
Ruolin Zhao ◽  
Liang Tian ◽  
Runze Duan ◽  
...  
Keyword(s):  
Cone Angle ◽  
Great Influence ◽  
Design Parameters ◽  
Sauter Mean Diameter ◽  
Hybrid Mode ◽  
Two Phase ◽  
Mean Diameter ◽  
Effervescent Atomizer ◽  
Atomization Characteristics ◽  
Swirl Atomizer

Abstract In this paper, the atomization characteristics of an effervescent atomizer were investigated. The velocity, Sauter Mean Diameter (SMD) and atomization cone angle of the droplets were measured using the Phase Doppler Analyzer (PDA) to discuss the effect of different design parameters. The results showed that the atomization was unstable at a small Gas-Liquid Rate (GLR) while the atomization proved gradually by increasing the GLR. The optimal atomization region was at a GLR=0.1. In the atomization process, there existed a typical velocity distribution for the swirl atomizer. The design parameters of atomizer provided a great influence on the Sauter Mean Diameter (SMD) and atomization cone angle. The experiment results showed that some droplets had negative velocities.

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.

scholarly journals Atomization Quality of Twin Fluid Atomizers for Gas Turbines

1982 ◽  
Author(s):  
M. M. Elkotb ◽  
M. A. Elsayed Mahdy ◽  
M. E. Montaser
Keyword(s):  
Size Distribution ◽  
Droplet Size ◽  
Gas Turbines ◽  
Cone Angle ◽  
Droplet Size Distribution ◽  
Diameter Ratio ◽  
Air Pressure ◽  
Sauter Mean Diameter ◽  
Flow Number ◽  
Mean Diameter

A detailed investigation of the effect of nozzle/needle diameter ratio, normal fuel area, swirler degree, air pressure, fuel pressure on flow number, cone angle and droplet size distribution of external mixing twin fluid atomizers is given in this paper. Forty atomizers have been constructed to prevent mutual effect of various parameters. Flow number and cone angle are found to increase with nozzle/diameter ratio, and to decrease with the increase of air pressure. Optimum fuel flow is obtained at swirler angle 30-deg, while cone angle increases with increase of swirler angle. Sauter mean diameter decreases with the increase of air pressure and decrease of fuel pressure. Suitable functions are derived for droplet size distribution, Sauter mean diameter, and flow number. They are suitable to predict the geometry of the atomizer and to be used also in a prediction model for the calculation of fuel concentration and heat release.

Atomization Characteristics of Effervescent Atomizer With Two-Aerator Tube

2004 ◽  
Author(s):  
Hyung Gon Kim ◽  
Shuichi Torii ◽  
Toshiaki Yano ◽  
Kyu Keun Song
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Orifice Diameter ◽  
Nozzle Orifice ◽  
Chamber Volume ◽  
Mixing Chamber ◽  
Mean Diameter ◽  
Effervescent Atomizer ◽  
Atomization Characteristics

An experimental study was conducted to investigate the atomization characteristics of spray from the effervescent atomizer, which has two-aerator tube. The atomization characteristics were examined through the influence of ALR (Air-to-Liquid Ratio) and the changes of atomizer geometry (nozzle orifice diameter, diffusion angle, mixing chamber volume). PDPA (Phase Doppler Particle Analyzer) was used to evaluate the SMD (Sauter Mean Diameter) and droplet velocity. During the experiments, the mass flow rate of liquid was kept constant at 2.8g/s and the mass flow rate of atomizing air was changed from 0.2 to 0.6g/s. Experimental results showed that SMD is not a linear function of ALR. While SMD is very sensitive to the changes of ALR, the changes of atomizer geometry have little effect on droplet mean diameter. As the effervescent atomizer with two-aerator tube is insensitive to the changes of atomizer geometry, it is expected that the effervescent atomizer with two-aerator tube is capable of requirements of many applications, without the drawbacks of atomization characteristics.

Numerical investigation of the full-cone spray structure and characteristics provided by a jet-swirl atomizer

2019 ◽  
Vol 233 (15) ◽  
pp. 5788-5800 ◽  
Author(s):  
Mohammad Amin Hassani ◽  
Abbas Elkaie ◽  
Maziar Shafaee
Keyword(s):  
Spray Parameters ◽  
Sauter Mean Diameter ◽  
Spray Cone ◽  
Spray Tip Penetration ◽  
Spray Structure ◽  
Mean Diameter ◽  
Swirl Atomizer ◽  
Pressure Swirl ◽  
Breakup Model ◽  
Good Agreement

Jet-swirl atomizers are one of the pressure-swirl atomizers that produce full-cone spray. Although many hollow-cone pressure-swirl sprays have been studied, characteristic investigation of pressure-swirl full-cone sprays are limited to a few experimental, analytical, and numerical works where each of them investigate some of the main spray parameters. The few existing numerical studies are limited to calculate the coefficient of discharge and spray cone angle. Current numerical study investigate a newly developed jet-swirl atomizer with pressure-swirl full-cone spray, which considers other important full-cone spray characteristics including Sauter mean diameter, D10, and spray tip penetration along with the spray structure. In this study, a full-cone spray based on a newly developed jet-swirl injector is numerically simulated and analyzed using sprayFoam solver in the OpenFOAM 4.1 software. The existing code of the solver is developed and its dictionary is modified. The C+ + Sauter mean diameter and D10 codes on the cross-sectional surface are developed and this feature is added to the sprayFoam solver. The pre-published experimental and current work numerical results were in good agreement. In the simulation process, blob sheet model is used for the spray primary breakup. Two models including Taylor analogy breakup and Reitz–Diwakar have been used for the secondary breakup of the developed jet-swirl atomizer. This work shows that the results of the Reitz–Diwakar model are close to that of the Taylor analogy breakup model. The time-varying results of Sauter mean diameter, D10, and spray tip penetration are found to be in good agreement in both models. The results show that the Reitz–Diwakar model is stabilized somewhat later than the Taylor analogy breakup model. The simulated spray structure shows that the density of droplets is higher in the spray center region and this density is gradually reduced through the radial direction. The results along the radius show that the diameter of the droplets becomes larger while moving away from the center of the spray.

scholarly journals Analysis of ethanol and butanol direct-injection spark-ignition sprays using two-phase structured laser illumination planar imaging droplet sizing

2018 ◽  
Vol 11 ◽  
pp. 175682771877249 ◽  
Author(s):  
Matthias Koegl ◽  
Yogeshwar Nath Mishra ◽  
Michael Storch ◽  
Chris Conrad ◽  
Edouard Berrocal ◽  
...  
Keyword(s):  
Direct Injection ◽  
Spark Ignition ◽  
Mie Scattering ◽  
Laser Induced Fluorescence ◽  
Planar Imaging ◽  
Sauter Mean Diameter ◽  
Two Phase ◽  
Laser Illumination ◽  
Mean Diameter ◽  
Direct Injection Spark Ignition

This paper reports on the spray structure of the biofuels, ethanol, and butanol generated by a multihole direct-injection spark-ignition injector, which is studied in a constant volume chamber. The spray shape and structure are analyzed using two-phase structured laser illumination planar imaging where both laser-induced fluorescence and Mie-scattering light are recorded simultaneously for the extraction of instantaneous laser-induced fluorescence/Mie-scattering ratio images. Quantitative planar measurements of the droplet Sauter mean diameter are conducted, using calibration data from phase-Doppler anemometry. The resulting Sauter mean diameters are presented for ethanol and butanol at various fuel temperatures at different times after the start of injection. It is found that an increase in fuel temperature results in a faster atomization and higher evaporation rate, which leads to reduced spray tip penetration and smaller droplet Sauter mean diameter. At equivalent conditions, butanol consistently showed larger spray tip penetration in comparison to ethanol. This behavior is due to the higher surface tension and viscosity of butanol resulting in the formation of larger droplets and larger Sauter mean diameters in the whole spray region. Finally, the butanol injection also shows larger cyclic variations in the spray shape from injection to injection which is explained by the internal nozzle flow that is influenced by larger fuel viscosity as well. The Sauter mean diameter distribution is also compared to phase-Doppler anemometry data showing good agreement and an uncertainty analysis of the structured laser illumination planar imaging-laser-induced fluorescence/Mie-scattering technique for planar droplet sizing in direct-injection spark-ignition sprays is presented.

scholarly journals Energy equilibrium analysis in the effervescent atomization

Open Physics ◽  
2020 ◽  
Vol 18 (1) ◽  
pp. 925-932
Author(s):  
Runze Duan ◽  
Ziwei Feng ◽  
Hongbin Duan ◽  
Huiru Qu ◽  
Liting Tian ◽  
...  
Keyword(s):  
Surface Tension ◽  
Flow Characteristics ◽  
Equilibrium Analysis ◽  
Liquid Viscosity ◽  
Sauter Mean Diameter ◽  
Mean Diameter ◽  
Compressed Gas ◽  
Energy Equilibrium ◽  
Swirl Atomizer ◽  
Gas Expansion

Abstract In this paper, the flow characteristics and energy equilibrium analysis of the effervescent atomization had been investigated theoretically and experimentally. The effect of the gas–liquid rate (GLR from 0.04 to 0.15) on the atomization stability was revealed. When the GLR was small, the atomization was unstable. The atomization was gradually stable with an increase in the GLR. The optimal atomization region can be obtained. The Sauter mean diameter (SMD) of the droplets was measured by the phase Doppler analyzer. The SMD decreases with an increase in the GLR. The energy equilibrium analysis was investigated for the swirl atomizer theoretically and experimentally. The results show that the energy dissipation terms are mainly compressed gas expansion, liquid viscosity dissipation, and resistance losses. However, the ratio of the spray kinetic energy and the surface tension energy to the total energy is small.

scholarly journals Atomization and combustion characteristics of a fuel–water rapid internal mixing injector

2019 ◽  
Author(s):  
Aizam Shahroni Mohd Arshad
Keyword(s):  
Water Content ◽  
Fuel Injection ◽  
Fuel Vapor ◽  
Sauter Mean Diameter ◽  
Liquid Ratio ◽  
Emulsified Fuel ◽  
Content Ratio ◽  
Internal Mixing ◽  
Mean Diameter ◽  
Atomization Characteristics

In this study, we investigated the atomization characteristics of rapid internal mixing injector (RIM injector) developed in our laboratory. RIM injector successfully emulsifies base fuel without any surfactant just before fuel injection. The diameter of droplet discharged from RIM injector was evaluated based on processing of shadowgraph images. It was found that Sauter mean diameter (SMD) of droplet is determined by the gas to liquid ratio (GLR) and viscosity of emulsified fuel. The increasing GLR decreases SMD value. As water content ratio is increased, the inner structure of droplet changes to W/O type emulsion. The emulsification increases its viscosity, which deteriorates the atomization characteristics. We proposed an empirical formula as functions of GLR and Reynolds number reproducing the deterioration resulting from increasing viscosity. The formula successfully predicts the SMD variation with respect to GLR and water content ratio. Finally, we examined the effect of atomization air ratio on NOx and PM emissions. The quantity of atomization air significantly influences the PM emission because the increasing air improves the mixing of fuel vapor with combustion air.

scholarly journals Evaluation of Atomization Characteristics of Second Generation Biodiesel Using Air Blast Atomizer

2018 ◽  
Vol 7 (4.35) ◽  
pp. 772
Author(s):  
Gopinathan Muthaiyah ◽  
Kumaran Palanisamy
Keyword(s):  
Gas Turbine ◽  
Second Generation ◽  
High Viscosity ◽  
Spray Angle ◽  
Biodiesel Fuel ◽  
Sauter Mean Diameter ◽  
Evaporation Time ◽  
Air Blast ◽  
Mean Diameter ◽  
Atomization Characteristics

Biodiesel is one of the well-known renewable fuels that can be produced from organic oils and animal fats. Biodiesel fuel that meets ASTM D6751 fuel standards can replace diesel for reciprocating engine. On the other hand, biodiesel can also be considered for gas turbine application in power generation. Nevertheless, inferior properties of biodiesel such as high viscosity, density and surface tension results in inferior atomization and high emission which consequently hinders the fuel for gas turbine utilisation and generate higher emission pollutants. Therefore, this work focused on the evaluation of atomization characteristics of second generation biodiesel which is produced using microwave assisted post treatment scheme. The atomisation characteristics of second generation biodiesel was evaluated using air blast atomiser in terms of spray angle and spray length. Subsequently, numerical evaluation was performed to evaluate sauter mean diameter and droplet evaporation time of second generation biodiesel.  The results show, atomization characteristics of second generation biodiesel has improved in terms of spray angle and spray length, sauter mean diameter and shorter evaporation time compared to biodiesel which is commonly referred to as first generation biodiesel and fossil diesel.

scholarly journals The Two-Phase Conical Swirl Atomizers: Spray Characteristics

Energies ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 3416 ◽  
Author(s):  
Marek Ochowiak ◽  
Andżelika Krupińska ◽  
Sylwia Włodarczak ◽  
Magdalena Matuszak ◽  
Małgorzata Markowska ◽  
...  
Keyword(s):  
Flow Rate ◽  
Discharge Coefficient ◽  
Experimental Studies ◽  
Central Area ◽  
Spray Angle ◽  
Sauter Mean Diameter ◽  
Spray Characteristics ◽  
Two Phase ◽  
Mean Diameter ◽  
The Impact

This paper presents the results of experimental studies on two-phase conical swirl atomizers. The impact of various atomizer geometries and different operational parameters of the atomization process on the spray characteristics was investigated. The influence of the mixing chamber height HS to diameter DS ratio and the volumetric flow rates of liquid and gas on the discharge coefficient values, spray angle, droplet size expressed by Sauter mean diameter D32, volumetric and radial distributions of droplet diameters in the spray stream were determined. The analysis of results showed that the discharge coefficient values depend on the Reynolds number for liquid and gas and the atomizer geometry. The spray angle increases as the flow rate of liquid and gas increases depending on the applied atomizer construction. The Sauter mean diameter value is correlated with the geometric dimensions of the atomizer swirl chamber. The rapid increase in D32 occurs after exceeding the value HS/DS ≈ 3. The Sauter mean diameter also depends on the operating parameters. A central area of stream is filled with smaller sized droplets as the gas flow rate increases.

Effects of orifice divergence on hollow cone spray at low injection pressures

2018 ◽  
Vol 233 (11) ◽  
pp. 4091-4105 ◽  
Author(s):  
Kushal Ghate ◽  
Thirumalachari Sundararajan
Keyword(s):  
Cone Angle ◽  
Sheet Thickness ◽  
Liquid Sheet ◽  
Divergence Angle ◽  
Sauter Mean Diameter ◽  
Spray Cone Angle ◽  
Spray Cone ◽  
Air Core ◽  
Mean Diameter ◽  
Injection Pressures

In this work, the effects of orifice divergence on spray characteristics have been reported. Parameters such as spray cone angle, liquid sheet thickness, coefficient of discharge, break-up length, and Sauter mean diameter are greatly affected by the half divergence angle [Formula: see text] at orifice exit. An experimental investigation is carried out in which water sprays from five atomizers having half divergence angle values of 0°, 5°, 10°, 15°, and 20° are studied at different injection pressures. Image processing techniques are used to measure spray cone angle and break-up length from spray images, whereas the sheet thickness outside the orifice exit is obtained using the scattered light from a thin Nd-YAG Laser beam. Phase Doppler interferometry is also used to obtain the Sauter mean diameter at different axial locations. A few numerical simulations based on the volume of fluid method are included to obtain physical insight of the liquid film development and air core flow inside the atomizer. It is observed that the liquid sheet thickness as well as tangential and radial components of velocity at orifice exit are modified drastically with a change in half divergence angle. As a consequence, the droplet size distribution is also altered by variation in the nozzle divergence angle. The mechanism responsible for such variations in the spray behavior is identified as the formation of an air core or air cone inside the liquid injector as a result of the swirl imparted to the liquid flow.

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