Experimental Study of Spray Characteristics at Cold Start and Elevated Ambient Pressure using Hybrid Airblast Pressure-Swirl Atomizer

2019 ◽  
Author(s):  
Dongyun Shin ◽  
Andrew J. Bokhart ◽  
Neil S. Rodrigues ◽  
Paul Sojka ◽  
Jay P. Gore ◽  
...  
Keyword(s):  
Experimental Study ◽  
Ambient Pressure ◽  
Cold Start ◽  
Spray Characteristics ◽  
Swirl Atomizer ◽  
Pressure Swirl ◽  
Pressure Swirl Atomizer

Nonlinear Breakup Model for a Liquid Sheet Emanating From a Pressure-Swirl Atomizer

2007 ◽  
Vol 129 (4) ◽  
pp. 945-953 ◽  
Author(s):  
Ashraf A. Ibrahim ◽  
Milind A. Jog
Keyword(s):  
Flow Field ◽  
Ambient Pressure ◽  
Internal Flow ◽  
Liquid Sheet ◽  
Nonlinear Instability ◽  
Breakup Length ◽  
Sheet Breakup ◽  
Swirl Atomizer ◽  
Pressure Swirl ◽  
Pressure Swirl Atomizer

Predictions of breakup length of a liquid sheet emanating from a pressure-swirl (simplex) fuel atomizer have been carried out by computationally modeling the two-phase flow in the atomizer coupled with a nonlinear analysis of instability of the liquid sheet. The volume-of-fluid (VOF) method has been employed to study the flow field inside the pressure-swirl atomizer. A nonlinear instability model has been developed using a perturbation expansion technique with the initial amplitude of the disturbance as the perturbation parameter to determine the sheet instability and breakup. The results for sheet thickness and velocities from the internal flow solutions are used as input in the nonlinear instability model. Computational results for internal flow are validated by comparing film thickness at exit, spray angle, and discharge coefficient with available experimental data. The predictions of breakup length show a good agreement with semiempirical correlations and available experimental measurements. The effect of elevated ambient pressure on the atomizer internal flow field and sheet breakup is investigated. A decrease in air core diameter is obtained at higher ambient pressure due to increased liquid-air momentum transport. Shorter breakup lengths are obtained at elevated air pressure. The coupled internal flow simulation and sheet instability analysis provides a comprehensive approach to modeling sheet breakup from a pressure-swirl atomizer.

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.

Experimental Investigations of Spray Characteristics of a Pressure-Swirl Atomizer

2019 ◽  
Vol 234 (5) ◽  
pp. 643-654 ◽  
Author(s):  
Xiongjie Fan ◽  
Cunxi Liu ◽  
Yong Mu ◽  
Haitao Lu ◽  
Jinhu Yang ◽  
...  
Keyword(s):  
Surface Wave ◽  
Liquid Film ◽  
Fuel Temperature ◽  
Spray Characteristics ◽  
Spray Cone ◽  
Breakup Length ◽  
Swirl Atomizer ◽  
Pressure Swirl ◽  
The Impact ◽  
Pressure Swirl Atomizer

Spray characteristics of a pressure-swirl atomizer are investigated using high-speed shadowgraph technique under different pressure drops (Δ P) and fuel temperatures ( T). An image processing method is developed using MATLAB. The results illustrate that the mass flow rate climbs with the increase of Δ P, while the discharge coefficient ( Cd) decreases firstly and then climbs with the increase of Δ P. Δ P has larger effect on the cone angle relative to fuel temperature. With the increase of Δ P, the shape of liquid film changes from ‘onion’ to ‘tulip’ and finally be fully developed spray cone. Meanwhile, the surface of liquid film becomes smoother with the increase of Δ P. The average breakup length climbs, then decreases to nearly a constant value with the increase of Δ P, which is induced by the “Impact wave,” surface wave, and turbulent energy. There are little differences on the shape of the liquid film under different temperatures, and temperature has different influence on breakup length under different Δ P. Both the fuel temperature and Δ P have significant impact on the surface wavelength ( λ) and velocities ( U, V) of surface wave. The width of fuel stream becomes larger with the increase of Δ P and fuel temperature. The results can further deepen the understanding of spray characteristics of pressure-swirl atomizer.

Experimental Studies on Fuel Spray Characteristics of Pressure-Swirl Atomizer and Air-Blast Atomizer

2021 ◽  
Vol 30 (2) ◽  
pp. 729-741
Author(s):  
Kaixing Wang ◽  
Xiongjie Fan ◽  
Fuqiang Liu ◽  
Cunxi Liu ◽  
Haitao Lu ◽  
...  
Keyword(s):  
Experimental Studies ◽  
Fuel Spray ◽  
Spray Characteristics ◽  
Air Blast ◽  
Swirl Atomizer ◽  
Pressure Swirl ◽  
Pressure Swirl Atomizer

scholarly journals Effect of Low Ambient Pressure on Spray Cone Angle of Pressure Swirl Atomizer

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Zhengyan Guo ◽  
Yi Jin ◽  
Kai Zhang ◽  
Kanghong Yao ◽  
Yunbiao Wang ◽  
...  
Keyword(s):  
High Speed ◽  
Ambient Pressure ◽  
Cone Angle ◽  
Spray Angle ◽  
High Speed Photography ◽  
Spray Cone Angle ◽  
Spray Cone ◽  
Swirl Atomizer ◽  
Pressure Swirl ◽  
Pressure Swirl Atomizer

Pressure swirl atomizers are widely used in gas turbine combustor; this paper is aimed at researching the effect of low ambient pressure (0.1 MPa to 0.01 MPa, lower than an atmosphere) on the spray cone angle of pressure swirl atomizer. The spray angle is captured by high-speed photography; then, an image post program is used to process the spray angle magnitude. A mathematical model of a single droplet’s movement and trajectory based on force analysis is proposed to validate the spray angle variation. The maximum variation of the spray cone angle, which is observed when fuel supply pressure drop through the atomizer is 1 MPa as the ambient pressure decreases from 0.1 MPa to 0.01 MPa, is found to be 23.9%. The experimental results show that the spray cone angle is expected to increase with the ambient pressure decrease; meanwhile, mathematical results agree well with this trend.

scholarly journals Experimental and Analytical Investigation on the Variation of Spray Characteristics Along Radial Distance Downstream of a Pressure Swirl Atomizer

1986 ◽  
Vol 108 (3) ◽  
pp. 473-478 ◽  
Author(s):  
Y. H. Zhao ◽  
W. M. Li ◽  
J. S. Chin
Keyword(s):  
Drop Size ◽  
Laser Light ◽  
Radial Distance ◽  
Analytical Investigation ◽  
Laser Light Scattering ◽  
Sauter Mean Diameter ◽  
Spray Characteristics ◽  
Swirl Atomizer ◽  
Pressure Swirl ◽  
Pressure Swirl Atomizer

The variation of spray characteristics (Sauter Mean Diameter and Rosin-Rammler drop-size distribution parameter) downstream of a pressure swirl atomizer along radial distance has been measured by laser light scattering technology. An analytical model has been developed that is capable of predicting the variation of spray characteristics along radial distance. A comparison between the prediction and experimental data shows excellent agreement. It shows that the spray model proposed, although relatively simple, is correct and can be used with some expansion and modification to predict more complicated spray systems.

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