Measurements of Droplet Velocity Fields in Sprays from Liquid Jets Injected in High-Speed Crossflows Using PIV

2020 ◽  
pp. 93-102
Author(s):  
Venkat S. Iyengar ◽  
K. Sathiyamoorthy ◽  
J. Srinivas ◽  
P. Pratheesh Kumar ◽  
P. Manjunath
Keyword(s):  
High Speed ◽  
Velocity Fields ◽  
Droplet Velocity ◽  
Liquid Jets

scholarly journals Velocity Profiles in a Cylindrical Liquid Jet by Reconstructed Velocimetry

2012 ◽  
Vol 134 (1) ◽  
Author(s):  
J. R. Castrejón-Pita ◽  
S. D. Hoath ◽  
I. M. Hutchings
Keyword(s):  
High Speed ◽  
Laser Sheet ◽  
Velocity Profiles ◽  
Velocity Fields ◽  
Liquid Jets ◽  
Reconstruction Method ◽  
Central Plane ◽  
Seed Particles ◽  
Transparent Liquid ◽  
The Difference

An experimental setup and a simple reconstruction method are presented to measure velocity fields inside slightly tapering cylindrical liquid jets traveling through still air. Particle image velocimetry algorithms are used to calculate velocity fields from high speed images of jets of transparent liquid containing seed particles. An inner central plane is illuminated by a laser sheet pointed at the center of the jet and visualized through the jet by a high speed camera. Optical distortions produced by the shape of the jet and the difference between the refractive index of the fluid and the surrounding air are corrected by using a ray tracing method. The effect of the jet speed on the velocity fields is investigated at four jet speeds. The relaxation rate for the velocity profile downstream of the nozzle exit is reasonably consistent with theoretical expectations for the low Reynolds numbers and the fluid used, although the velocity profiles are considerably flatter than expected.

High-Speed Photography of Liquid Jets

1975 ◽  
pp. 442-447 ◽  
Author(s):  
D. A. Gorham ◽  
J. E. Field
Keyword(s):  
High Speed ◽  
Liquid Jets ◽  
High Speed Photography

Partially-Averaged Navier–Stokes Simulations of High-Speed Mixing Environment

2014 ◽  
Vol 136 (6) ◽  
Author(s):  
Ravichandra Srinivasan ◽  
Sharath S. Girimaji
Keyword(s):  
High Speed ◽  
Cavity Flow ◽  
Velocity Fields ◽  
Navier Stokes ◽  
High Fidelity ◽  
Variable Resolution ◽  
Air Mixing

Accurate simulation of the fuel-air mixing environment is crucial for high-fidelity scramjet calculations. We compute the velocity fields of jet into supersonic freestream flow and cavity flow typical of scramjet flame-holding applications at different scale resolutions using the partially-averaged Navier–Stokes (PANS) method. We present a sequence of variable resolution computations to demonstrate the potential of PANS method for high-speed mixing environment calculations.

scholarly journals Generation of High-Speed Liquid Jets by High-Speed Impact of a Projectile.

1995 ◽  
Vol 38 (2) ◽  
pp. 181-190 ◽  
Author(s):  
Hong-Hui Shi ◽  
Kazuyoshi Takayama
Keyword(s):  
High Speed ◽  
Liquid Jets ◽  
High Speed Impact

Flow Characteristics of Rectangular Liquid Jets Injected Into Low Subsonic Crossflow

2019 ◽  
Author(s):  
M. Tadjfar ◽  
A. Jaberi ◽  
R. Shokri
Keyword(s):  
High Speed ◽  
Flow Characteristics ◽  
Combustion Efficiency ◽  
Liquid Jets ◽  
High Speed Photography ◽  
Aspect Ratios ◽  
Jet Trajectory ◽  
Wide Range ◽  
Circular Holes ◽  
Subsonic Crossflow

Abstract Perpendicular injection of liquid jets into gaseous crossflow is well-known as an effective way to obtain good mixing between liquid fuel and air crossflow. Mostly, injectors with circular holes were used as the standard method of fuel spraying. However, recently a great attention to injectors with non-circular holes has emerged that aims to improve the quality of fuel mixing and consequently combustion efficiency. In the present work, rectangular injectors with different aspect ratios varying from 1 to 4 were experimentally studied. Using a wind tunnel with maximum air velocity of 42 m/s, tests were performed for a wide range of flow conditions including liquid-to-air momentum ratios of 10, 20, 30 and 40. Backlight shadowgraphy and high speed photography were employed to capture the instantaneous physics of the liquid jets discharged into gaseous crossflow. The flow physics of the rectangular liquid jets were investigated by means of flow visualizations. Different regimes of flow breakup including capillary, arcade, bag and multimode were observed for rectangular jets. Moreover, a new technique was used to calculate the trajectory of the liquid jets. It was shown the nozzle’s shape has no significant effect on jet trajectory. Also, the momentum ratio was found to has a profound effect on jet trajectory.

Breakup characteristics of high speed liquid jets from a single-hole injector

Fuel ◽  
2020 ◽  
pp. 119784
Author(s):  
Shengqi Wu ◽  
Mark Meinhart ◽  
Benjamin Petersen ◽  
Jianwen Yi ◽  
Margaret Wooldridge
Keyword(s):  
High Speed ◽  
Liquid Jets ◽  
Single Hole

Comparative study on interfacial oscillations of rectangular and elliptical liquid jets

2020 ◽  
Vol 234 (7) ◽  
pp. 1272-1286 ◽  
Author(s):  
Amin Jaberi ◽  
Mehran Tadjfar
Keyword(s):  
Aspect Ratio ◽  
Weber Number ◽  
High Speed ◽  
Nozzle Geometry ◽  
Liquid Jets ◽  
High Speed Photography ◽  
Aspect Ratios ◽  
Water Jets ◽  
Switching Phenomenon ◽  
Axis Switching

The instability characteristics and flow structures of water jets injected from rectangular and elliptical nozzles with aspect ratios varying from 2 to 6 were experimentally studied and compared. Shadowgraph technique was employed for flow visualization, and structures on the liquid jet surface were captured using high speed photography. It was found that disturbances originating from the nozzle geometry initially perturbed the liquid column, and then, at high jet velocities, disturbances generated within the flow dominated the jet surface. It was also found that rectangular nozzles introduced more disturbances into the flow than the elliptical ones. The characteristic parameters of axis-switching phenomenon including wavelength, frequency, and amplitude were measured and compared. Axis-switching wavelength was found to increase linearly with Weber number. Also, the wavelengths of rectangular jets were longer than the elliptical jets. Further, the frequency of axis-switching was shown to be reduced with increase of both Weber number and aspect ratio. It was observed that the axis-switching amplitude increased monotonically, reached a peak, and then decreased gradually. It was also found that the axis-switching amplitude varied with Weber number. At lower values of Weber number, the rectangular nozzles had higher amplitude than the elliptical nozzles. However, at higher values of Weber number, this relation was reversed, and the elliptical nozzles had the higher axis-switching amplitudes. This reversal Weber number decreased with the orifice aspect ratio. The reversal Weber number for aspect ratio of 4 was about 289, and it had decreased to 144 for the aspect ratio of 6.

scholarly journals Experiment on the Breakup of Liquid Jets in Different Cross-Airflows

2019 ◽  
Vol 2019 ◽  
pp. 1-13
Author(s):  
Tian Deng ◽  
Wei Chen ◽  
Xing-ming Ren ◽  
Shuai Jiang ◽  
Chao-hua Yuan
Keyword(s):  
Penetration Depth ◽  
High Speed ◽  
Velocity Ratio ◽  
Flux Ratio ◽  
Liquid Jets ◽  
Uniform Shear ◽  
Jet Trajectory ◽  
Uniform Case ◽  
Jet Penetration ◽  
Exponential Relation

The experiment is conducted with a high-speed camera to investigate the breakup processes of liquid jets in uniform, shear-laden, and swirling cross-airflows. The liquid used in the test is water, the nozzle diameter is 2 mm, and the liquid-to-air momentum flux ratio q ranges from 5 to 3408.5. The results indicate that liquid jets break up to form small droplets in the uniform cross-airflow. There is an exponential relation between the broken position and q. In the shear-laden cross-airflow, the penetration depth of the jet is similar to that of the uniform case, both of which increase with the increase of q. When q and the mean Weber number are the same as the uniform case, the penetration depth of the jet increases by 25% when the velocity ratio of the upper and lower inlets is UR=5; the jet penetration depth decreases by 47.2% when the ratio of UR=0.2 and the jet breaks up quickly and the atomization effect will be better. In the swirling cross-airflow, the jet trajectory is similar to the uniform case and also satisfies the exponential property. When the swirl is weak (swirling number SN=0.49), the jet penetration depth increases compared to the uniform case; when the swirl is strong (SN=0.82), the cross-swirling airflow restrains the jet penetration depth.

Experimental Characterization of Intrinsic Properties Associated With Air-Assisted Liquid Jet and Liquid Sheet

2018 ◽  
Vol 140 (5) ◽  
Author(s):  
K. Balaji ◽  
V. Sivadas ◽  
Vishnu Radhakrishna ◽  
Khushal Ashok Bhatija ◽  
K. Sai Charan
Keyword(s):  
High Speed ◽  
Liquid Sheet ◽  
Interfacial Instability ◽  
Wave Number ◽  
Liquid Jets ◽  
Liquid Jet ◽  
Experimental Characterization ◽  
Interfacial Wave ◽  
Visualization Techniques

The present study focuses on experimental characterization of interfacial instability pertinent to liquid jet and liquid sheet in the first wind-induced zone. To accomplish this objective, the interfacial wave growth rate, critical wave number, and breakup frequency associated with air-assisted atomizer systems were extracted by utilizing high-speed flow visualization techniques. For a range of liquid to gas velocities tested, nondimensionalization with appropriate variables generates the corresponding correlation functions. These functions enable to make an effective comparison between interfacial wave developments for liquid jet and sheet configurations. It exhibits liquid sheets superiority over liquid jets in the breakup processes leading to efficient atomization.

Characteristics of impact-driven high-speed liquid jets in water

Shock Waves ◽  
2013 ◽  
Vol 23 (2) ◽  
pp. 105-114 ◽  
Author(s):  
A. Matthujak ◽  
C. Kasamnimitporn ◽  
W. Sittiwong ◽  
K. Pianthong ◽  
K. Takayama ◽  
...  
Keyword(s):  
High Speed ◽  
Liquid Jets
Sign in / Sign up

Export Citation Format

Share Document