Effect of Liquid Compressibility at a Jet Impact on a Wall

The flat-plate momentum test bench is a widely used experimental device in the verification of the momentum law of fluid mechanics, and its error characteristics are of positive significance for theoretical research and engineering innovation and expansion. The SPH-FEM coupling algorithm and spectrum analysis method are used to calculate and analyze the displacement response and spectrum characteristics of the characteristic points of the sensor under different jet loads. Based on them, the cause, classification, law, scope, influence and control method of the measurement error of the system are discussed and analyzed with the application of the error theory and the lateral effect theory of strain gauges; combined with physical experiments, the relevant analysis methods and conclusions are verified. The results show that the measurement error of the system includes linear error and periodic error. Structural deformation in the direction of jet impact is the main source of linear error; linear error increases with the increase of jet loads. Meanwhile, periodic vibration in non-jet direction is the main cause of periodic error, and the periodic error decreases with the increase of jet loads.

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Air Bubble Entrainment, Breakup, and Interplay in Vertical Plunging Jets

Journal of Fluids Engineering ◽

10.1115/1.4039715 ◽

2018 ◽

Vol 140 (9) ◽

Cited By ~ 3

Author(s):

Numa Bertola ◽

Hang Wang ◽

Hubert Chanson

Keyword(s):

High Speed ◽

Point Explosion ◽

Air Bubble ◽

Bubble Breakup ◽

Jet Impact ◽

Bubble Entrainment ◽

Bubble Interaction ◽

Onset Velocity ◽

Air Cavities ◽

Interaction Behaviors

The entrainment, breakup, and interplay of air bubbles were observed in a vertical, two-dimensional supported jet at low impact velocities. Ultra-high-speed movies were analyzed both qualitatively and quantitatively. The onset velocity of bubble entrainment was between 0.9 and 1.1 m/s. Most bubbles were entrained as detached bubbles from elongated air cavities at the impingement point. Explosion, stretching, and dejection mechanisms were observed for individual bubble breakup, and the bubble interaction behaviors encompassed bubble rebound, “kiss-and-go,” coalescence and breakup induced by approaching bubble(s). The effects of jet impact velocity on the bubble behaviors were investigated for impact velocities from 1.0 to 1.36 m/s, in the presence of a shear flow environment.

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Possibility of the Use of Different Types of Materials in Passive Ventilation Systems of Munitions

Problems of Mechatronics Armament Aviation Safety Engineering ◽

10.5604/01.3001.0009.2979 ◽

2016 ◽

Vol 7 (3) ◽

pp. 21-34

Author(s):

Adam WIŚNIEWSKI

Keyword(s):

Shape Memory ◽

Thermal Loading ◽

Slow Heating ◽

Military Equipment ◽

Bullet Fragment ◽

Jet Impact ◽

Different Types ◽

Mathematical Equations ◽

Shape Memory Materials ◽

Shaped Charge Jet

The paper presents different types of insensitive munition used in military equipment, especially in western countries. Tests of this munition, their parameters, e.g. fast and slow heating, bullet, fragment and shaped charge jet impact and sympathetic reaction are described. The characteristics of shape-memory materials like alloys and polymers are presented. Behaviour of shape-memory alloy is explained by example of TiNi al-loys during mechanical or thermal loading, and martensitic transformation into austen-ite during unloading. Material parameters of the TiNi alloys, their testing and mathematical equations are shown. Venting systems used in the explosive reactive armour cassettes are presented. Different examples of materials, including shape-memory materials in munition, are demonstrated.

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Micro-grooving on quartz crystals by an abrasive air jet

Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science ◽

10.1177/0954406211410260 ◽

2011 ◽

Vol 225 (9) ◽

pp. 2161-2173 ◽

Cited By ~ 6

Author(s):

J Wang ◽

A Moridi ◽

P Mathew

Keyword(s):

Performance Measures ◽

Process Parameters ◽

Traverse Speed ◽

Groove Depth ◽

Impact Angle ◽

Quartz Crystals ◽

Air Jet ◽

Jet Impact ◽

Mass Flowrate ◽

Micro Grooving

An investigation of the micro-grooving performance of abrasive air jet (AAJ) on quartz crystals is presented and discussed. An experimental study was carried out first to understand the effect of process parameters on the major grooving performance measures such as groove depth, groove width, kerf taper, and surface roughness. Plausible trends for these grooving performance measures with respect to the various process variables, such as air pressure, nozzle traverse speed, jet impact angle, and abrasive mass flowrate, are discussed. It is found that AAJ is an effective technology for micromachining of quartz crystals and the grooving performance can be improved or optimized by selecting the process parameters properly. Predictive models are then developed for quantitatively estimating the micro-grooving performance. The models are finally verified by an experiment. It shows that the model predictions are in good agreement with the experimental results under the corresponding conditions.

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Diagnosis of Oxide Films by Cavitation Micro-Jet Impact

MATERIALS TRANSACTIONS ◽

10.2320/matertrans.44.327 ◽

2003 ◽

Vol 44 (2) ◽

pp. 327-335 ◽

Cited By ~ 21

Author(s):

Yeong-Jern Chen ◽

Li-Wu Huang ◽

Teng-Shih Shih

Keyword(s):

Oxide Films ◽

Jet Impact

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Modelling of water jet impact on molten metal

Journal of Physics Conference Series ◽

10.1088/1742-6596/2119/1/012073 ◽

2021 ◽

Vol 2119 (1) ◽

pp. 012073

Author(s):

S E Yakush ◽

N S Sivakov ◽

V I Melikhov ◽

O I Melikhov

Keyword(s):

Steam Explosion ◽

Water Jet ◽

Point Of View ◽

Change Model ◽

Water Pool ◽

Jet Impact ◽

Melt Water ◽

Height Dependence ◽

The Impact ◽

Primary Melt

Abstract Splashes of high-temperature melt spreading over a water pool bottom can be a reason for the formation of a zone where melt, water and steam are mixed, providing conditions for powerful steam explosions. The paper considers the formation of melt splashes arising from the impact of a water jet on the surface of the melt. Numerical simulations are performed in 3D formulation, using the VOF method and an improved phase change model. The evolution of melt surface following the water jet impact is demonstrated, including the formation of a cavern, a primary melt splash known as the crown, as well as a secondary splash following the collapse of the cavern, known as the cumulative jet. Parametric study for the melt splash height dependence on the water jet geometry and velocity is carried out. The results of numerical analysis are discussed from the point of view of the similarity with respect to the momentum and kinetic energy of water jet. The significance of the results for the steam explosion problem is discussed.

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