Experiment on Breakup Processes and Surface Waves of Round Liquid Jets in Crossflows

2010 ◽  
Author(s):  
Ying Zhu ◽  
Yong Huang ◽  
Fang Wang ◽  
Xiong-hui Wang
Keyword(s):  
Surface Wave ◽  
High Speed ◽  
Liquid Column ◽  
Injection Velocity ◽  
Liquid Jet ◽  
Initial Surface ◽  
Jet Injection ◽  
Airflow Velocity ◽  
Test Operation ◽  
The Cross

An experiment was conducted to investigate the surface wave development and the breakup processes of round water jets in cross airflows at room temperature and pressure by high-speed photography. The jets were injected normal to the crossflow direction opposing gravitation forces from a plain orifice nozzle with the diameter of 0.3 mm and length-to-diameter ratio of 40. Successive images were recorded by a megapixel high-speed video camera with maximum frame rate frequency of 10000 Hz. The jet injection velocity varied from 3.8 m/s to 7.8 m/s. The crossflow velocity varied from 25.6 m/s to 35.1 m/s which resulted in the liquid-to-air momentum flux ratio varied from 10.2 to 80. The experimental results indicate that the surface of the liquid jet is smooth at first and then the initial surface wave appears a distance downstream along the jet column. The structure of the liquid jet would be successively deformed to a spiral wave in the cross airflow. When the amplitude grows large enough the liquid column is pinched into segments from the locations of wave troughs due to surface tension. With the increasing of the cross airflow velocity the aerodynamic forces, instead of the surface tension, begin to play an important role in the column breakup process. The liquid column is disintegrated by the cutting of the aerodynamic forces. The smooth length defined as the distance from where initial surface wave appears to the nozzle exit is correlated with the test operation parameters. The smooth length will be increased with the increasing of the jet injection velocity and decreased with the increasing of airflow velocity. The liquid jet column will bend and fluctuate in the crossflow and the normalized fluctuation displacement of the liquid column is correlated with the test operation parameters. The results depict that the increasing of jet injection velocity will diminish the jet column fluctuation whereas the increasing of airflow velocity will enhance it. The liquid column breakup points also fluctuate in the cross airflow. The coordinates of the time-averaged breakup locations are correlated with the liquid-to-air momentum ratio. The equation of the near-field liquid column trajectory curve before the column breakup point is concluded. The curves based on the equation agree well with the tested results.

A Model on Liquid Penetration Into Soft Material With Application to Needle-Free Jet Injection

2010 ◽  
Vol 132 (10) ◽  
Author(s):  
Kai Chen ◽  
Hua Zhou ◽  
Ji Li ◽  
Gary J. Cheng
Keyword(s):  
Mathematical Model ◽  
High Speed ◽  
Injection System ◽  
Liquid Jet ◽  
Liquid Penetration ◽  
Jet Injection ◽  
Free Jet ◽  
Calculation Results ◽  
Jet Penetration ◽  
Continuous Deposition

A mathematical model has been presented for a high speed liquid jet penetration into soft solid by a needle-free injection system. The model consists of a cylindrical column formed by the initial jet penetration and an expansion sphere due to continuous deposition of the liquid. By solving the equations of energy conservation and volume conservation, the penetration depth and the radius of the expansion sphere can be predicted. As an example, the calculation results were presented for a typical needle-free injection system into which a silicon rubber was injected into. The calculation results were compared with the experimental results.

Visualization of Pulsed Aerated Liquid Jet in Supersonic Cross Flow

2005 ◽  
Author(s):  
H. Sapmaz ◽  
B. Alkan ◽  
C. X. Lin ◽  
C. Ghenai
Keyword(s):  
Combustion Chamber ◽  
High Speed ◽  
Liquid Fuel ◽  
Cross Flow ◽  
Liquid Jet ◽  
Pure Liquid ◽  
Jet Injection ◽  
Fuel Jet ◽  
Air Mixing ◽  
Jet Penetration

The success of supersonic air-breathing propulsion systems will be largely dependent on efficient injection, mixing, and combustion inside the supersonic combustion chamber. Fuel/air mixing enhancement inside the combustion chamber will depend on the strategies used to control the fuel jet penetration and liquid fuel droplet size, trajectory, and dispersion. We present in these paper experimental results on the mixing of pure liquid jet, aerated liquid jet and pulsed aerated liquid jet in supersonic cross flow. Transverse aerated liquid jet injection will offer relatively rapid near-field mixing, good fuel penetration and better atomization of liquid fuel. Fully modulated or pulsed fuel jet injection will introduce additional supplementary turbulent mixing. High speed imaging system is used in this study for the visualization of the injection of liquid jet in high speed cross flow. The results presented in this paper show the effect of jet/cross flow momentum ratio, the gas/liquid mass ratio and pulsing frequency on the penetration of aerated liquid jet in supersonic cross-flow. The data generated in this study will be used for the development of active control strategies to optimize the liquid fuel jet penetration and supersonic fuel/air mixing.

NONLINEAR SIMULATION OF A HIGH-SPEED, VISCOUS LIQUID JET

1998 ◽  
Vol 8 (2) ◽  
pp. 155-178 ◽  
Author(s):  
J. H. Hilbing ◽  
Stephen D. Heister
Keyword(s):  
Viscous Liquid ◽  
High Speed ◽  
Liquid Jet ◽  
Nonlinear Simulation

scholarly journals Observation and analysis of diving beetle movements while swimming

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Debo Qi ◽  
Chengchun Zhang ◽  
Jingwei He ◽  
Yongli Yue ◽  
Jing Wang ◽  
...  
Keyword(s):  
Swimming Speed ◽  
High Speed ◽  
Kinematic Model ◽  
Movement Pattern ◽  
Unmanned Vehicles ◽  
Power Stroke ◽  
Cross Sectional ◽  
Motion Data ◽  
The Cross ◽  
Diving Beetle

AbstractThe fast swimming speed, flexible cornering, and high propulsion efficiency of diving beetles are primarily achieved by their two powerful hind legs. Unlike other aquatic organisms, such as turtle, jellyfish, fish and frog et al., the diving beetle could complete retreating motion without turning around, and the turning radius is small for this kind of propulsion mode. However, most bionic vehicles have not contained these advantages, the study about this propulsion method is useful for the design of bionic robots. In this paper, the swimming videos of the diving beetle, including forwarding, turning and retreating, were captured by two synchronized high-speed cameras, and were analyzed via SIMI Motion. The analysis results revealed that the swimming speed initially increased quickly to a maximum at 60% of the power stroke, and then decreased. During the power stroke, the diving beetle stretched its tibias and tarsi, the bristles on both sides of which were shaped like paddles, to maximize the cross-sectional areas against the water to achieve the maximum thrust. During the recovery stroke, the diving beetle rotated its tarsi and folded the bristles to minimize the cross-sectional areas to reduce the drag force. For one turning motion (turn right about 90 degrees), it takes only one motion cycle for the diving beetle to complete it. During the retreating motion, the average acceleration was close to 9.8 m/s2 in the first 25 ms. Finally, based on the diving beetle's hind-leg movement pattern, a kinematic model was constructed, and according to this model and the motion data of the joint angles, the motion trajectories of the hind legs were obtained by using MATLAB. Since the advantages of this propulsion method, it may become a new bionic propulsion method, and the motion data and kinematic model of the hind legs will be helpful in the design of bionic underwater unmanned vehicles.

Behavior of Unsteady Turbulent Starting Round Jets

2012 ◽  
Vol 134 (6) ◽  
Author(s):  
Neerav Abani ◽  
Jaal B. Ghandhi
Keyword(s):  
High Speed ◽  
Penetration Rate ◽  
Injection Rate ◽  
Injection Velocity ◽  
Time Varying ◽  
Velocity Change ◽  
Rate Of Penetration ◽  
Round Jets ◽  
The Difference ◽  
Sudden Decrease

Turbulent starting jets with time-varying injection velocities were investigated using high-speed schlieren imaging. Two solenoid-controlled injectors fed a common plenum upstream of an orifice; using different upstream pressures and actuation times, injection-rate profiles with a step increase or decrease in injection velocity were tested. The behavior of the jet was found to be different depending on the direction of the injection-velocity change. A step increase in injection velocity resulted in an increased rate of penetration relative to the steady-injection case, and a larger increase in injection velocity resulted in an earlier change in the tip-penetration rate. The step-increase data were found to be collapsed by scaling the time by a convective time scale based on the tip location at the time of the injection-velocity change and the difference in the injection velocities. A sudden decrease in injection velocity to zero was found to cause a deviation from the corresponding steady-pressure case at a time that was independent of the initial jet velocity, i.e., it was independent of the magnitude of the injection-velocity change. Two models for unsteady injection from the literature were tested and some deficiencies in the models were identified.

Large-scale structure and entrainment in the supersonic mixing layer

1995 ◽  
Vol 284 ◽  
pp. 171-216 ◽  
Author(s):  
N. T. Clemens ◽  
M. G. Mungal
Keyword(s):  
Mach Number ◽  
High Speed ◽  
Large Scale ◽  
Mixture Fraction ◽  
Mixing Layer ◽  
Mie Scattering ◽  
Planar Laser ◽  
The Cross ◽  
Convective Mach Number ◽  
Stream Direction

Experiments were conducted in a two-stream planar mixing layer at convective Mach numbers,Mc, of 0.28, 0.42, 0.50, 0.62 and 0.79. Planar laser Mie scattering (PLMS) from a condensed alcohol fog and planar laser-induced fluorescence (PLIF) of nitric oxide were used for flow visualization in the side, plan and end views. The PLIF signals were also used to characterize the turbulent mixture fraction fluctuations.Visualizations using PLMS indicate a transition in the turbulent structure from quasi-two-dimensionality at low convective Mach number, to more random three-dimensionality for$M_c\geqslant 0.62$. A transition is also observed in the core and braid regions of the spanwise rollers as the convective Mach number increases from 0.28 to 0.62. A change in the entrainment mechanism with increasing compressibility is also indicated by signal intensity profiles and perspective views of the PLMS and PLIF images. These show that atMc= 0.28 the instantaneous mixture fraction field typically exhibits a gradient in the streamwise direction, but is more uniform in the cross-stream direction. AtMc= 0.62 and 0.79, however, the mixture fraction field is more streamwise uniform and with a gradient in the cross-stream direction. This change in the composition of the structures is indicative of different entrainment motions at the different compressibility conditions. The statistical results are consistent with the qualitative observations and suggest that compressibility acts to reduce the magnitude of the mixture fraction fluctuations, particularly on the high-speed edge of the layer.

Experimental Analysis of Water/Oil Displacement Tests in Horizontal Pipe

SPE Journal ◽  
2021 ◽  
pp. 1-18
Author(s):  
Roberto Fernando Leuchtenberger ◽  
Jorge Luiz Biazussi ◽  
William Monte Verde ◽  
Marcelo de Souza Castro ◽  
Antonio Carlos Bannwart
Keyword(s):  
Viscous Liquid ◽  
High Speed ◽  
Cold Water ◽  
Tap Water ◽  
Logistic Function ◽  
Oil Field ◽  
Injection Velocity ◽  
Internal Diameter ◽  
Oil Viscosity ◽  
Horizontal Pipe

Summary Production shutdowns occur often throughout the life cycle of an oil field. In offshore fields, shutdown situations are accompanied by an intense heat exchange between pipeline and cold water, which exponentially increases oil viscosity. Such an event may lead to serious difficulty to restart the production, or even render it unfeasible, especially for heavy oil fields. Therefore, a preventive procedure is required to remove the ultraviscous oil from pipelines and risers; for example, by pumping diesel or methanol in a flush procedure. Designing an efficient cleanup procedure is therefore essential in terms of time, amount of fluid injected, and pumping system requirements. However, the amount of research published in this area is limited. In this paper, we propose a comprehensive analysis on how the displacement of a viscous liquid by a less-viscous liquid occurs in a pipeline through footages in different segments, varying the injection velocity. Two mineral oils with different viscosities and tap water were used as working fluids for this study. The experimental setup was built with a horizontal 10-m-long acrylic pipe with 19-mm internal diameter. Two high-speed cameras were placed both in the inlet and outlet segments. Our results demonstrate how water displaces viscous oil in a pipeline, showing different flow configurations as superficial water velocity increases, depending on the oil viscosity and distance from the inlet. A dimensionless analysis was performed by a combination of the forces that govern the flow and dimensionless groups found in literature. The results show an expected area of optimum values regarding cleaning time according to flow configuration. A unidimensional model using a logistic function was proposed and showed a good agreement with the experimental data. The model itself proven to be an easy tool for industry and academic purposes, supporting even more robust and elaborated models in the future. NOTE: Supplemental material is available with this paper and is available online under the Supplementary Data heading at https://doi.org/10.2118/205356-PA.

Elastic liquid jet impaction on a high-speed moving surface

AIChE Journal ◽  
2012 ◽  
Vol 58 (11) ◽  
pp. 3568-3577 ◽  
Author(s):  
B. Keshavarz ◽  
S. I. Green ◽  
D. T. Eadie
Keyword(s):  
High Speed ◽  
Liquid Jet ◽  
Moving Surface ◽  
Elastic Liquid
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