The Two-Phase High-Speed Stream at the Centerline of a Hollow-Cone Spray Produced by a Pressure-Swirl Nozzle

2016 ◽  
Vol 56 (1) ◽  
pp. 359-367 ◽  
Author(s):  
Wei Du ◽  
Ze Sun ◽  
Guimin Lu ◽  
Jianguo Yu
Keyword(s):  
High Speed ◽  
Hollow Cone ◽  
Two Phase ◽  
High Speed Stream ◽  
Pressure Swirl ◽  
Hollow Cone Spray

Asymmetric Transverse Acoustic Excitation of a Hollow Cone Spray Sheet With Air Swirl

2019 ◽  
Author(s):  
Rohit R. Bhattacharjee ◽  
Aravind I. Babu ◽  
Satyanarayanan R. Chakravarthy
Keyword(s):  
Cone Angle ◽  
Acoustic Excitation ◽  
Hollow Cone ◽  
Breakup Length ◽  
Swirl Angle ◽  
Transverse Acoustic ◽  
Spray Axis ◽  
Acoustic Forcing ◽  
Pressure Swirl ◽  
Hollow Cone Spray

Abstract The objective of this study was to experimentally observe the effects of externally perturbing a hollow cone spray sheet with acoustic excitation. These effects were quantified by measuring changes in the spray breakup length, swirl angle, and oscillatory behaviour of the sheet edge. We used a pressure swirl nozzle embedded into a swirler with 60° vane angles and a geometric swirl no. of SG = 0.981. Water was used to produce a hollow cone spray sheet and air was used as our swirler agent. For asymmetric forcing, only one side of the spray chamber was attached to a transverse duct (aligned perpendicular to the spray axis) along with two speakers. The duct harmonics were found to be 115 Hz, 204 Hz, and 313 Hz. Our experimental modes were also found to be comparable with results obtained numerically using the acoustic solver package from ANSYS. Our results show that for most cases the spray edges, cone angle, and breakup length responds to the acoustic forcing. While the cone angle increased with air swirl, for some cases without acoustic forcing the breakup length increased with air swirl.

Experimental Investigation of a Hollow Cone Spray Using Laser Diagnostics

2013 ◽  
Author(s):  
Mithun Das ◽  
Souvick Chatterjee ◽  
Swarnendu Sen ◽  
Achintya Mukhopadhyay
Keyword(s):  
Gas Turbines ◽  
High Speed ◽  
Laser Diagnostics ◽  
Laser Sheet ◽  
Droplet Diameter ◽  
Injection Pressure ◽  
Diameter Distribution ◽  
Hollow Cone ◽  
Wide Range ◽  
Hollow Cone Spray

Atomization of fuel is a key integral part for efficient combustion in gas turbines. This demands a thorough investigation of the spray characteristics using innovative and useful spray diagnostics techniques. In this work, an experimental study is carried out on commercial hollow cone nozzle (Lechler) using laser diagnostics techniques. A hollow cone spray is useful in many applications because of its ability to produce fine droplets. But apart from the droplet diameter, the velocity field in the spray is also an important parameter to monitor and has been addressed in this work. Kerosene is used as the test fuel which is recycled using a plunger pump providing a variation in the injection pressure from 100psi to 300psi. An innovative diagnostic technique used in this study is through illumination of the spray with a continuous laser sheet and capturing the same with a high speed camera. A ray of laser beam is converted to a planer sheet using a lens combination which is used to illuminate a cross section of the hollow cone spray. This provides a continuous planar light source which allows capturing high speed images at 285 fps. The high speed images, thus obtained are processed to understand the non-linearity associated with disintegration of the spray into fine droplets. The images are shown to follow a fractal representation and the fractal dimension is found to increase with rise in injection pressure. Also, using PDPA, the droplet diameter distribution is calculated at different spatial and radial locations at wide range of pressure.

Effect of Azimuthal Velocity Fluctuation on Hollow Cone Spray

2017 ◽  
Author(s):  
Aravind I. Babu ◽  
Satya Chakravarthy
Keyword(s):  
Velocity Fluctuation ◽  
High Speed ◽  
Cone Angle ◽  
Azimuthal Velocity ◽  
Mean Flow ◽  
Hollow Cone ◽  
Spray Cone Angle ◽  
Spray Cone ◽  
Velocity Fluctuations ◽  
Hollow Cone Spray

This paper reports an experimental investigation on the effect of imposed azimuthal velocity fluctuation on the spray characteristics of a hollow cone spray produced from a pressure-swirl nozzle. This effect is inferred by performing experiments separately on 0° and 60° axial straight vane swirlers oriented concentric to the spray nozzle for the air-flow subjected to upstream acoustic forcing. The hollow cone spray is subjected to external excitation using a loudspeaker at two different frequencies and two amplitudes. These frequencies correspond to the resonant frequencies of the plenum. The 60° vane swirler, when subjected to acoustic excitation, produces axial and azimuthal velocity fluctuation downstream of the swirler, whereas the 0° swirler produces only axial velocity fluctuation downstream of the swirler. In both 60° and 0° swirlers, the downstream velocity fluctuation due to acoustic disturbances propagate at the speed of sound. In addition, the velocity fluctuations produced due to the excitation are convected by the mean flow. This results in a combined effect of velocity fluctuations at the swirler exit. The hollow cone spray responds more readily to excitation at low frequencies than higher frequencies. This is observed from the high-speed shadowgraph images. The high-speed shadowgraph images acquired are processed to extract spray cone angle. The phase averaged spray cone angle fluctuates for different phase angle within an acoustic cycle. The analysis of the high-speed shadowgraph images shows that the cone angle fluctuation amplitude is higher for the 0° swirler as compared to the 60° swirler. The variation of the liquid sheet thickness and breakup length due to excitation is captured using high-speed planar laser induced fluorescence. The study clearly demonstrates that azimuthal velocity fluctuation affects the spray formation process.

Studies on the Behavior of Droplets and the Air Flow in a Hollow-Cone Spray

1998 ◽  
Vol 120 (3) ◽  
pp. 586-592 ◽  
Author(s):  
Tatsuyuki Okamoto ◽  
Toshimi Takagi ◽  
Toshikazu Kaji ◽  
Katsunori Shimazaki ◽  
Kenji Nakanishi
Keyword(s):  
Equations Of Motion ◽  
Liquid Sheet ◽  
Experimental Result ◽  
Hollow Cone ◽  
Air Stream ◽  
Droplet Sizes ◽  
Swirl Atomizer ◽  
Pressure Swirl ◽  
Hollow Cone Spray

Experimental and numerical investigations are made on the behavior of droplets in a hollow-cone spray paying attention to the liquid sheet formed at the orifice of pressure-swirl atomizer. Simultaneous measurements of droplet sizes and velocities are made by phase-Doppler technique and numerical simulations are carried out based on the transient Eulerian equations for the gas and the Lagrangian equation for the droplets, taking account of the liquid sheet formed at the atomizer orifice. It is shown that the simulation gives good predictions by incorporating the existence of the liquid sheet. The predicted results indicate that the movement of the liquid sheet induces a strong air stream which acts as a strong side wind against the droplets immediately after breakup. This air stream selectively transports small droplets toward the central region and plays an essential role in the classification of droplets by size. Accordingly, the existence of the liquid sheet is significant for the characteristics of droplet dispersion and it should not be neglected in the prediction of hollow-cone spray flows. In addition, the shape of the liquid sheet is theoretically computed based on the simplified equations of motion. The comparison between the theoretical computation and the experimental result suggests that the surface tension of liquid is predominant in determining the shape of the liquid sheet.

Experimental Investigation of a Hollow Cone Spray Using Laser Diagnostics

2014 ◽  
Vol 136 (7) ◽  
Author(s):  
Mithun Das ◽  
Souvick Chatterjee ◽  
Achintya Mukhopadhyay ◽  
Swarnendu Sen
Keyword(s):  
Gas Turbines ◽  
High Speed ◽  
Laser Diagnostics ◽  
Laser Sheet ◽  
Droplet Diameter ◽  
Injection Pressure ◽  
Diameter Distribution ◽  
Hollow Cone ◽  
Wide Range ◽  
Hollow Cone Spray

Atomization of fuel is a key integral part for efficient combustion in gas turbines. This demands a thorough investigation of the spray characteristics using innovative and useful spray diagnostics techniques. In this work, an experimental study is carried out on a commercial hollow cone nozzle (Lechler) using laser diagnostics techniques. A hollow cone spray is useful in many applications because of its ability to produce fine droplets. But apart from the droplet diameter, the velocity field in the spray is also an important parameter to monitor and has been addressed in this work. Kerosene is used as the test fuel, which is recycled using a plunger pump providing a variation in the injection pressure from 100 to 300 psi. An innovative diagnostic technique used in this study is through illumination of the spray with a continuous laser sheet and capturing the same with a high speed camera. A ray of a laser beam is converted to a planer sheet using a lens combination which is used to illuminate a cross section of the hollow cone spray. This provides a continuous planar light source which allows capturing high speed images at 285 fps. The high speed images thus obtained are processed to understand the nonlinearity associated with disintegration of the spray into fine droplets. The images are shown to follow a fractal representation and the fractal dimension is found to increase with rise in injection pressure. Also, using PDPA, the droplet diameter distribution is calculated at different spatial and radial locations at a wide range of pressure.

MODELING ATOMIZATION PROCESSES OF PRESSURE-SWIRL HOLLOW-CONE FUEL SPRAYS

1997 ◽  
Vol 7 (6) ◽  
pp. 663-684 ◽  
Author(s):  
Zhiyu Han ◽  
Scott Parrish ◽  
Patrick V. Farrell ◽  
Rolf D. Reitz
Keyword(s):  
Hollow Cone ◽  
Fuel Sprays ◽  
Pressure Swirl

Characteristics of Leeward Shear Layer Structure of Hollow-Cone Spray in Gaseous Crossflow

AIAA Journal ◽  
2021 ◽  
Vol 59 (1) ◽  
pp. 405-409
Author(s):  
Haibin Zhang ◽  
Shilin Gao ◽  
Bofeng Bai ◽  
Yechun Wang
Keyword(s):  
Shear Layer ◽  
Layer Structure ◽  
Hollow Cone ◽  
Hollow Cone Spray

Two-Phase Short Circuit in the Power Grid Powered by a Transformer with a Y/Δ-11 Winding Connection

2020 ◽  
pp. 25-30
Author(s):  
Aleksandr S. Serebryakov ◽  
Vladimir L. Osokin ◽  
Sergey A. Kapustkin
Keyword(s):  
High Speed ◽  
Short Circuit ◽  
Relay Protection ◽  
Electric Circuit ◽  
Operational Reliability ◽  
Research Purpose ◽  
Industrial Complex ◽  
Two Phase ◽  
Short Circuit Currents ◽  
Secondary Winding

The article describes main provisions and relations for calculating short-circuit currents and phase currents in a three-phase traction transformer with a star-triangle-11 connection of windings, which feeds two single-phase loads in AC traction networks with a nominal voltage of 25 kilovolts. These transformers provide power to the enterprises of the agro-industrial complex located along the railway line. (Research purpose) The research purpose is in substantiating theoretical equations for digital intelligent relay protection in two-phase short circuits. (Materials and methods) It was found that since the sum of instantaneous currents in each phase is zero, each phase of the transformer works independently. We found that this significantly simplifies the task of analyzing processes with a two-phase short circuit. In this case, the problem of calculating short-circuit currents in the traction network can be simplified by reducing it to the calculation of an ordinary electric circuit with three unknown currents. (Results and discussion) The article describes equations for calculating short-circuit resistances for one phase of the transformer when connecting the secondary winding as a star or a triangle. The currents in the phases of the transformer winding at short circuit for the star-triangle-11 and star-star-with-ground schemes are compared. It was found that when calculating short-circuit currents, there is no need to convert the secondary winding of the traction transformer from a triangle to a star. (Conclusions) It was found that the results of the research can be used in the transition of relay protection systems from electromagnetic relays to modern high-speed digital devices, which will increase the operational reliability of power supply systems for traction and non-traction power consumers.

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