Supersonic Jet Impingement on a Cylinder and Characterization of the Resulting Deflected Jets

2014 ◽  
Vol 136 (11) ◽  
Author(s):  
Ameya Pophali ◽  
Markus Bussmann ◽  
Honghi Tran
Keyword(s):  
High Speed ◽  
Supersonic Jet ◽  
Jet Impingement ◽  
High Speed Photography ◽  
Pitot Pressure ◽  
Kraft Recovery Boilers ◽  
Recovery Boilers ◽  
Transverse Distance ◽  
Oval Cross Section ◽  
Jet Characteristics

The interaction between a mildly underexpanded supersonic jet and a single cylinder was studied experimentally at laboratory scale by using the schlieren technique coupled with high-speed photography and pitot pressure measurements. This study was motivated by the need to optimize sootblowing operation in kraft recovery boilers. The effects of the transverse distance between the jet and cylinder centerlines (eccentricity), nozzle–cylinder distance, and cylinder size on jet–cylinder interaction were determined. Results show that upon impingement on a cylinder, a supersonic jet deflects at an angle and creates a weaker supersonic jet that we refer to as a “secondary” jet. The angle and strength of the deflected or secondary jet depend on the eccentricity between the primary jet and cylinder centerlines. When a jet impinges on a cylinder of diameter comparable to that of the jet or smaller, secondary jets form not only when the cylinder is placed close to the nozzle (in the stronger portion of the jet) but also when the cylinder is placed far away (in the jet's weaker portion; up to 20–24 nozzle exit diameters in the present study). Changing the eccentricity slightly results in a significant change in the secondary jet characteristics. For a cylinder much larger than the jet, secondary jets do not form at zero eccentricity (head-on impingement); the eccentricity at which they begin to form increases with the cylinder size. A study of the secondary jets shows that they spread out much more than the primary jet and are sheet- or fan-like with an oblong, oval cross section. The centerline pitot pressure of the secondary jets remains as high as the primary jet for a considerable distance from the tube only during weak interaction between the primary jet and the cylinder (i.e., during strongly eccentric/off-centerd impingement). As the interaction between the primary jet and the cylinder intensifies at lower eccentricities, the maximum centerline pitot pressure of the secondary jet decreases, and the pitot pressure decreases more quickly with distance from the tube.

scholarly journals Study of Lubricant Jet Flow Phenomena in Spur Gears—Out of Mesh Condition

1978 ◽  
Vol 100 (1) ◽  
pp. 61-68 ◽  
Author(s):  
D. P. Townsend ◽  
L. S. Akin
Keyword(s):  
High Speed ◽  
Gear Tooth ◽  
Velocity Ratio ◽  
Jet Impingement ◽  
Gear Ratio ◽  
Experimental Program ◽  
High Speed Photography ◽  
Gear Mesh ◽  
Mesh Condition ◽  
Oil Jet

An analysis was conducted for oil jet lubrication on the disengaging side of a gear mesh. Results of the analysis were computerized and used to determine the oil jet impingement depth for several gear ratios and oil jet to pitch line velocity ratios. An experimental program was conducted on the NASA gear test rig using high-speed photography to experimentally determine the oil jet impingement depth on the disengaging side of mesh. Impingement depth reaches a maximum at gear ratio near 1.5 where chopping by the leading gear tooth limits the impingement depth. The pinion impingement depth is zero above a gear ratio of 1.172 for a jet velocity to pitch time velocity ratio of 1.0 and is similar for other velocity ratios. The impingement depth for gear and pinion are equal and approximately one-half the maximum at a gear ratio of 1.0. Impingement depth on either the gear or pinion may be improved by relocation of the jet from the pitch line or by changing the jet angle. Results of the analysis were verified by experimental results using a high-speed camera and a well lighted oil jet.

Flow Development of a Liquid Sheet Issued Into Low-Speed Airstream

2020 ◽  
Author(s):  
Amin Jaberi ◽  
Mehran Tadjfar
Keyword(s):  
High Speed ◽  
Liquid Sheet ◽  
Liquid Jets ◽  
High Speed Photography ◽  
Low Speed ◽  
Liquid Sheets ◽  
Flow Development ◽  
Flow Feature ◽  
Subsonic Crossflow ◽  
Jet Characteristics

Abstract In this study, a liquid sheet with an aspect ratio of 90 and a thickness of 0.35 was experimentally investigated when issued into a low-speed subsonic crossflow. High speed photography and shadowgraphy technique were employed to capture the instantaneous physics of the liquid sheet. Flow visualizations were used to investigate the flow development of the liquid sheet. It was found that this flow exhibited a completely different flow structure than circular or other non-circular liquid sheets. It was found that the liquid sheet developed a concave-like shape in the presence of the transverse airstream. This phenomenon, named as inflated sheet, was absent in regular circular liquid jets injected into gaseous crossflow. It was revealed the inflated sheet was the main feature of the liquid sheet that made the jet characteristics unique. The flow feature of the inflated sheet structure and its alteration with flow condition was fully examined. Moreover, the width and trajectory of the liquid sheet were quantitatively studied at different Weber numbers and for the constant momentum ratio of 40. It was found that the fluid width could be a useful parameter to distinguish different regimes of the flow.

An explanation for the phase lag in supersonic jet impingement

2017 ◽  
Vol 815 ◽  
Author(s):  
Joel L. Weightman ◽  
Omid Amili ◽  
Damon Honnery ◽  
Julio Soria ◽  
Daniel Edgington-Mitchell
Keyword(s):  
Acoustic Waves ◽  
High Speed ◽  
Feedback Loop ◽  
Supersonic Jet ◽  
Jet Impingement ◽  
Phase Lag ◽  
Loop Equation ◽  
Image Velocimetry ◽  
Impinging Flows ◽  
First Time

For the first time, a physical mechanism is identified to explain the phase lag term in Powell’s impinging feedback loop equation (Powell, J. Acoust. Soc. Am., vol. 83 (2), 1988, pp. 515–533). Ultra-high-speed schlieren reveals a previously unseen periodic transient shock in the wall jet region of underexpanded impinging flows. The motion of this shock appears to be responsible for the production of the acoustic waves corresponding to the impingement tone. It is suggested that the delay between the inception of the shock and the formation of the acoustic wave explains the phase lag in the aeroacoustic feedback process. This suggestion is quantitatively supported through an assessment of Powell’s feedback equation, using high-resolution particle image velocimetry and acoustic measurements.

Crack divergence phenomena in tempered glass

2020 ◽  
Vol 13 (3) ◽  
pp. 115-129
Author(s):  
Shin’ichi Aratani
Keyword(s):  
Optimal Design ◽  
High Speed ◽  
Glass Plate ◽  
Acute Angle ◽  
Divergence Angle ◽  
High Speed Photography ◽  
Tempered Glass ◽  
Thick Glass

High speed photography using the Cranz-Schardin camera was performed to study the crack divergence and divergence angle in thermally tempered glass. A tempered 3.5 mm thick glass plate was used as a specimen. It was shown that two types of bifurcation and branching existed as the crack divergence. The divergence angle was smaller than the value calculated from the principle of optimal design and showed an acute angle.

Air port flow patterns in kraft recovery boilers

1996 ◽  
Vol 11 (2) ◽  
pp. 115-120
Author(s):  
D.C.S. Kuhn ◽  
T. Mao ◽  
H.N. Tran
Keyword(s):  
Flow Patterns ◽  
Kraft Recovery Boilers ◽  
Recovery Boilers

Experimental study of hydrodynamic effects in the inverse water hydrocarbon emulsions flow in microchannels

2016 ◽  
Vol 11 (1) ◽  
pp. 30-37 ◽  
Author(s):  
A.A. Rakhimov ◽  
A.T. Akhmetov
Keyword(s):  
High Speed ◽  
Petroleum Industry ◽  
Chemical Compounds ◽  
High Viscosity ◽  
Blocking Effect ◽  
High Speed Photography ◽  
Simple Chemical ◽  
Reported Study ◽  
Dynamic Blocking ◽  
Hydrodynamic Effects

The paper presents results of hydrodynamic and rheological studies of the inverse water hydrocarbon emulsions. The success of the application of invert emulsions in the petroleum industry due, along with the high viscosity of the emulsion, greatly exceeding the viscosity of the carrier phase, the dynamic blocking effect, which consists in the fact that the rate of flow of emulsions in capillary structures and cracks falls with time to 3-4 orders, despite the permanent pressure drop. The reported study shows an increase in viscosity with increasing concentration or dispersion of emulsion. The increase in dispersion of w/o emulsion leads to an acceleration of the onset of dynamic blocking. The use of microfluidic devices, is made by soft photolithography, along with high-speed photography (10,000 frames/s), allowed us to see in the blocking condition the deformation of the microdroplets of water in inverse emulsion prepared from simple chemical compounds.

scholarly journals Prey Capturing Dynamics and Nanomechanically Graded Cutting Apparatus of Dragonfly Nymph

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 559
Author(s):  
Lakshminath Kundanati ◽  
Prashant Das ◽  
Nicola M. Pugno
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
High Speed ◽  
Prey Capture ◽  
High Speed Photography ◽  
Sensory Organs ◽  
Dragonfly Nymph ◽  
Drag Forces ◽  
Predatory Insects ◽  
Dragonfly Nymphs

Aquatic predatory insects, like the nymphs of a dragonfly, use rapid movements to catch their prey and it presents challenges in terms of movements due to drag forces. Dragonfly nymphs are known to be voracious predators with structures and movements that are yet to be fully understood. Thus, we examine two main mouthparts of the dragonfly nymph (Libellulidae: Insecta: Odonata) that are used in prey capturing and cutting the prey. To observe and analyze the preying mechanism under water, we used high-speed photography and, electron microscopy. The morphological details suggest that the prey-capturing labium is a complex grasping mechanism with additional sensory organs that serve some functionality. The time taken for the protraction and retraction of labium during prey capture was estimated to be 187 ± 54 ms, suggesting that these nymphs have a rapid prey mechanism. The Young’s modulus and hardness of the mandibles were estimated to be 9.1 ± 1.9 GPa and 0.85 ± 0.13 GPa, respectively. Such mechanical properties of the mandibles make them hard tools that can cut into the exoskeleton of the prey and also resistant to wear. Thus, studying such mechanisms with their sensory capabilities provides a unique opportunity to design and develop bioinspired underwater deployable mechanisms.

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