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

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.

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Spray and atomization characteristics of gas-centered swirl coaxial injectors

International Journal of Spray and Combustion Dynamics ◽

10.1177/1756827716660225 ◽

2016 ◽

Vol 9 (2) ◽

pp. 127-140 ◽

Cited By ~ 2

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.

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A Comparison of Air-Blast and Flow-Blurring Injectors Using Phase Doppler Particle Analyzer Technique

Volume 2: Combustion, Fuels and Emissions ◽

10.1115/gt2009-60239 ◽

2009 ◽

Cited By ~ 7

Author(s):

Benjamin M. Simmons ◽

Heena V. Panchasara ◽

Ajay K. Agrawal

Keyword(s):

Vegetable Oil ◽

Laser Sheet ◽

High Viscosity ◽

Spray Angle ◽

Ambient Conditions ◽

Air Blast ◽

New Novel ◽

Significant Difference ◽

Phase Doppler Particle Analyzer ◽

Temperature And Pressure

Recent research on biofuels for power generation has typically focused on biodiesel because the biodiesel feedstrock, e.g., vegetable oil, poses significant combustion problems related to poor atomization. Existing injectors cannot effectively atomize high viscosity fuels such as vegetable oil. However, a new, novel flow-blurring (FB) injector concept has shown promise in overcoming the atomization problems. In this study, a FB injector is compared to a commercial air-blast (AB) injector operated with water at ambient conditions of temperature and pressure. Laser sheet visualization and Phase Doppler Particle Analyzer (PDPA) systems are used to obtain the spray characteristics for a range of air to liquid (ALR) ratios. Results show significant difference in distributions of Sauter Mean Diameters (SMDs), and mean and root-mean square axial velocity for the two injectors operated at a fixed ALR. In comparison to the AB injector, the FB injector produced spray with smaller SMDs, a smaller SMD range over the spray volume, higher RMS and mean axial velocities in the center region, and a compact spray with spray angle nearly independent of ALR. Results show that the FB injector is an effective way of atomizing liquids at relatively low ALRs compared to a traditional AB injector, without the additional pressure drop penalty.

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Influence of Residence Time on Fuel Spray Sauter Mean Diameter (SMD) and Emissions Using Biodiesel and its Blends in a Low NOx Gas Turbine Combustor

Volume 3: Coal, Biomass and Alternative Fuels; Cycle Innovations; Electric Power; Industrial and Cogeneration; Organic Rankine Cycle Power Systems ◽

10.1115/gt2016-58148 ◽

2016 ◽

Author(s):

Mohamed A. Altaher ◽

Hu Li ◽

Gordon E. Andrews

Keyword(s):

Gas Turbine ◽

Gas Turbines ◽

Fuel Spray ◽

Inlet Temperature ◽

Nox Emissions ◽

Gaseous Emissions ◽

Low Carbon ◽

Sauter Mean Diameter ◽

Gas Turbine Combustor ◽

Mean Diameter

Biodiesels have advantages of low carbon footprint, reduced toxic emissions, improved energy supply security and sustainability and therefore attracted attentions in both industrial and aero gas turbines sectors. Industrial gas turbine applications are more practical biodiesels due to low temperature waxing and flow problems at altitude for aero gas turbine applications. This paper investigated the use of biodiesels in a low NOx radial swirler, as used in some industrial low NOx gas turbines. A waste cooking oil derived methyl ester biodiesel (WME) was tested on a radial swirler industrial low NOx gas turbine combustor under atmospheric pressure, 600K air inlet temperature and reference Mach number of 0.017&0.023. The pure WME, its blends with kerosene (B20 and B50) and pure kerosene were tested for gaseous emissions and lean extinction as a function of equivalence ratio for both Mach numbers. Sauter Mean Diameter (SMD) of the fuel spray droplets was calculated. The results showed that the WME and its blends had lower CO, UHC emissions and higher NOx emissions than the kerosene. The weak extinction limits were determined for all fuels and B100 has the lowest value. The higher air velocity (at Mach = 0.023) resulted in smaller SMDs which improved the mixing and atomizing of fuels and thus led to reductions in NOx emissions.

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

10.31224/osf.io/te5jx ◽

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.

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The Two-Phase Conical Swirl Atomizers: Spray Characteristics

Energies ◽

10.3390/en13133416 ◽

2020 ◽

Vol 13 (13) ◽

pp. 3416 ◽

Cited By ~ 1

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.

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

Open Physics ◽

10.1515/phys-2019-0101 ◽

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.

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The Prediction of Sauter Mean Diameter for Gas Turbine Fuel Nozzles of Different Types

Journal of Engineering for Power ◽

10.1115/1.3230318 ◽

1980 ◽

Vol 102 (3) ◽

pp. 646-652 ◽

Cited By ~ 14

Author(s):

H. C. Simmons

Keyword(s):

Gas Turbine ◽

Present State ◽

State Of The Art ◽

Prediction Equation ◽

Published Data ◽

Sauter Mean Diameter ◽

Mean Diameter ◽

Different Types

Reviewing the more important published equations for predicting SMD for various types of fuel nozzles it is pointed out that there is no universal or common approach to cover different nozzle designs. In particular there is no effort to bridge the gap between pressure-atomizers and air-atomizers, especially the air-assisted simplex nozzle. Furthermore many of the equations provide no basis for estimating the effect of dimensions which is essential in modeling. An equation is presented, based on both new and published data, which satisfies these objections, and is shown to be related to previous methods. Suggestions are made with regard to the choice of constants in the prediction equation so as to represent fairly the present state of the art.

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Atomization and Droplet Dispersion of Low-Momentum Water Jet by High-Speed Crossflow Air Stream

2010 14th International Heat Transfer Conference, Volume 6 ◽

10.1115/ihtc14-22506 ◽

2010 ◽

Author(s):

Cuicui Liu ◽

Zeyi Jiang ◽

Huafei Liu ◽

Xinxin Zhang ◽

Shunhua Xiang

Keyword(s):

Group Velocity ◽

High Speed ◽

Water Jet ◽

Spray Angle ◽

Dominant Factor ◽

Sauter Mean Diameter ◽

Droplet Dispersion ◽

Jet Breakup ◽

Air Stream ◽

Mean Diameter

In this paper, a low-momentum water liquid jet emanating transversely into a high-speed air stream is investigated analytically and numerically. Viscous instability followed by Rayleigh-Taylor instability is used in the jet breakup analysis to obtain the Sauter Mean Diameter and the droplet group velocity after the breakup. With the analytical results, droplet dispersion in the air stream is simulated by the coupled Eulerian-Lagrangian approach, in which the root-normal distribution is adopted to represent the droplet diameter distribution. Water flux distribution and spray angle are obtained and validated by experimental data. The results show that the air velocity is a dominant factor on the Sauter Mean Diameter and droplet group velocity in the water jet breakup process and the spray angle is influenced by the water mass flux.

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Experimental comparison of the spray atomization of heavy and light fuel oil at different temperatures and pressures for pressure-swirl injector

Proceedings of the Institution of Mechanical Engineers Part A Journal of Power and Energy ◽

10.1177/0957650921994376 ◽

2021 ◽

pp. 095765092199437

Author(s):

Elyas Rostami ◽

Hossein Mahdavy Moghaddam

Keyword(s):

Film Thickness ◽

Liquid Film ◽

Diesel Fuel ◽

Temperature Increase ◽

Liquid Film Thickness ◽

Fuel Oil ◽

Spray Angle ◽

Breakup Length ◽

Fuel Atomization ◽

Mean Diameter

In this study, the atomization of heavy fuel oil (Mazut) and diesel fuel at different pressures is compared experimentally. Also, the effects of temperature on the Mazut fuel atomization are investigated experimentally. Mass flow rate, discharge coefficient, wavelength, liquid film thickness, ligament diameter, spray angle, breakup length, and sature mean diameter are obtained for the Mazut and diesel fuel. Fuels spray images at different pressures and temperatures are recorded using the shadowgraphy method and analyzed by the image processing technique. Error analysis is performed for the experiments, and the percentage of uncertainty for each parameter is reported. The experimental results are compared with the theoretical results. Also, Curves are proposed and plotted to predict changes in the behavior of atomization parameters. Diesel fuel has less viscosity than Mazut fuel. Diesel fuel has shorter breakup length, wavelength, liquid film thickness, and sature mean diameter than Mazut fuel at the same pressure. Diesel fuel has a larger spray angle and a larger discharge coefficient than Mazut fuel at the same pressure. As the pressure and temperature increase, fuel atomization improves. The viscosity of Mazut fuel is decreased by temperature increase. As the fuel injection pressure and temperature increase, breakup length, wavelength, liquid film thickness, and sature mean diameter decrease; also, spray angle increases.

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