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

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.

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 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.

Influence of the Fragmentation Behavior on Molten Material Jet Breakup in Coolant

2013 ◽  
Author(s):  
Yuzuru Iwasawa ◽  
Yutaka Abe ◽  
Akiko Kaneko ◽  
Taihei Kuroda ◽  
Eiji Matsuo ◽  
...  
Keyword(s):  
High Speed ◽  
Density Ratio ◽  
Heat Removal ◽  
Free Fall ◽  
Core Material ◽  
Dominant Factor ◽  
Sodium Coolant ◽  
Molten Material ◽  
Fragmentation Behavior ◽  
Jet Breakup

For the safety design of a Fast Breeder Reactor (FBR), Post Accident Heat Removal (PAHR) is required when a hypothetical Core Disruptive Accident (CDA) occurs. In PAHR, it is strongly required that the molten core material can be solidified and cooled down by the sodium coolant in a reactor vessel. In order to estimate whether the molten material jet is completely solidified by sodium coolant, it is necessary to understand the interaction between the molten core material and the coolant. The objective of the present study is to clarify the dominant factor of the jet breakup length and the size of the fragments experimentally. In this study, we injected molten material (Sn–Bi alloy) into coolant (water) at free fall speed. We can simulate an actual FBR system by using Sn-Bi alloy and water because the density ratio of them is similar to that of an actual FBR system. The jet breakup and the fragmentation behavior of the molten material jet were observed with a high speed video camera. In the previous study which we conducted, solidified crust is generated by the solidification on the molten material jet surface and affects the jet breakup and the fragmentation behavior. Then from the experimental results, in order to predict the size of fragments, it is constructed that the instability model based on hydrodynamic and material mechanics. Then in this paper, the surface close-up of the molten material jet was observed in order to investigate the effect of the solidification on the molten material jet surface.

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.

Experimental Analysis and Phenomenological Model for Liquid Jet Breakup in Swirling Flow of Air

2019 ◽  
Vol 141 (9) ◽  
Author(s):  
Tushar Sikroria ◽  
Abhijit Kushari
Keyword(s):  
High Speed ◽  
Swirling Flow ◽  
Liquid Jet ◽  
Swirl Number ◽  
Breakup Mechanism ◽  
Jet Breakup ◽  
Air Stream ◽  
Jet Penetration ◽  
Straight Flow ◽  
The Impact

This paper presents detailed analysis of an experimental investigation of the impact of swirl number of subsonic cross-flowing air stream on liquid jet breakup at an airflow Mach number of 0.12, which is typical in gas turbine conditions. Experiments are performed for four different swirl numbers (0, 0.2, 0.42, and 0.73) using swirl vanes at air inlet having angles of 0 deg, 15 deg, 30 deg, and 45 deg, respectively. Liquid to air momentum flux ratios (q) have been varied from 1 to 25. High-speed images of the interaction of liquid and air streams are captured and processed to estimate the jet penetration height as well as the breakup location for various flow conditions. The results show unique behavior for each swirl number, which departs from the straight flow correlations available in the literature. Based on the results, an attempt has been made to understand the physics of the phenomena and come up with a simplified physical model for prediction of jet penetration. Furthermore, the high-speed images show a dominant influence of liquid column fluttering on fracture mechanism (column or shear breakup mechanism).

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

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.

Radiated Sound of a High-Speed Water-Jet-Propelled Transportation Vessel

2016 ◽  
pp. 951-956
Author(s):  
Alexis B. Rudd ◽  
Michael F. Richlen ◽  
Alison K. Stimpert ◽  
Whitlow W. L. Au
Keyword(s):  
High Speed ◽  
Water Jet ◽  
Radiated Sound
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