Penetration process into a viscoelastic substance by high-speed liquid jet

Different blend ratio of ternary component fuel was tested inside a constant volume chamber to investigate fuel injection and combustion under similar real engine working conditions. Because liquid spray light scattering is the different reflective rate from the liquid droplets and its surrounding background, butanol-biodiesel-diesel liquid jet penetration length can be highlighted in the images taken by high speed camera. Various ambient temperatures from 800K to 1200K and fuel composition were investigated. Measured results showed that sudden but repeatable drop of liquid jet penetration length at constant ambient temperature conditions of 800K and 900K. With ambient temperature increasing, this phenomenon became weak and disappeared. So more works focus on non-combusting experiments in order to delete combustion reflect. With butanol and biodiesel content increasing, micro explosion becomes prone excited and more violent because of the enlarged differences in volatilities and boiling point among the components. It is concluded that micro explosion which will distinctly enhances premixed combustion process and heat release rate but it present under certain initial ambient temperature conditions only and the light fuel content shouldn’t be lower than 10%.

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Deformation and fracture mechanisms in the barrier of steel 08X18H10T (08Kh18N10T) in the penetration process of drummer with high speed

Application to Journal. Tambov University Reports. Series: Natural and Technical Sciences ◽

10.20310/1810-0198-2018-23-122p-67-69 ◽

2018 ◽

pp. 67-69

Author(s):

Aleksey Yurievich Grigorev ◽

Keyword(s):

High Speed ◽

Fracture Mechanisms ◽

Penetration Process ◽

Deformation And Fracture

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Estimation of High-Speed Liquid-Jet Velocity Using a Pyro Jet Injector

Scientific Reports ◽

10.1038/s41598-019-56511-x ◽

2019 ◽

Vol 9 (1) ◽

Author(s):

Naohisa Takagaki ◽

Toru Kitaguchi ◽

Masashi Iwayama ◽

Atsushi Shinoda ◽

Hiroshige Kumamaru ◽

...

Keyword(s):

Numerical Simulation ◽

High Speed ◽

Liquid Jet ◽

Liquid Density ◽

Liquid Viscosity ◽

Ejection Velocity ◽

Piston Motion ◽

Ansys Fluent ◽

Piston Displacement ◽

Jet Velocity

AbstractThe high-speed liquid-jet velocity achieved using an injector strongly depends on the piston motion, physical property of the liquid, and container shape of the injector. Herein, we investigate the liquid ejection mechanism and a technique for estimating the ejection velocity of a high-speed liquid jet using a pyro jet injector (PJI). We apply a two-dimensional numerical simulation with an axisymmetric approximation using the commercial software ANSYS/FLUENT. To gather the input data applied during the numerical simulation, the piston motion is captured with a high-speed CMOS camera, and the velocity of the piston is measured using motion tracking software. To reproduce the piston motion during the numerical simulation, the boundary-fitted coordinates and a moving boundary method are employed. In addition, we propose a fluid dynamic model (FDM) for estimating the high-speed liquid-jet ejection velocity based on the piston velocity. Using the FDM, we consider the liquid density variation but neglect the effects of the liquid viscosity on the liquid ejection. Our results indicate that the liquid-jet ejection velocity estimated by the FDM corresponds to that predicted by ANSYS/FLUENT for several different ignition-powder weights. This clearly shows that a high-speed liquid-jet ejection velocity can be estimated using the presented FDM when considering the variation in liquid density but neglecting the liquid viscosity. In addition, some characteristics of the presented PJI are observed, namely, (1) a very rapid piston displacement within 0.1 ms after a powder explosion, (2) piston vibration only when a large amount of powder is used, and (3) a pulse jet flow with a temporal pulse width of 0.1 ms.

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Study on the Composite Structure of Aluminum Foam-Filled Thin-Walled Metal Tube to Reduce the Charge Overload inside the Projectile during the Penetration Process

Shock and Vibration ◽

10.1155/2020/8887893 ◽

2020 ◽

Vol 2020 ◽

pp. 1-11

Author(s):

Fudi Liang ◽

Zengyou Liang ◽

Dezhi Deng

Keyword(s):

Reinforced Concrete ◽

Stress Analysis ◽

Composite Structure ◽

High Speed ◽

Aluminum Foam ◽

Metal Tube ◽

Penetration Process ◽

Mathematical Expressions ◽

Foam Filled ◽

Thin Walled

When a projectile penetrates a target at high speed, the charge loaded inside the projectile usually bears a high overload, which will consequently severely affect its performance. In order to reduce the overload of the charge during the penetration process, the structure of the projectile was improved by adding two buffers at both ends of the charge. In this study, the mathematical expressions were first gained about the axial buffering force generated by the thin-walled metal tube, aluminum foam, and the composite structure of aluminum foam-filled thin-walled metal tube when they were impacted by the high-speed mass block through reasonable assumptions and stress analysis. During the experiment on the high-speed projectile penetrating reinforced concrete target, the acceleration curve of the charge and the projectile body were obtained. The results show that the maximum overload that the charge was subjected to during the launch and penetration process was significantly reduced, and the change in overload, which the charge was subjected to during the penetration process, was also less obvious.

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Atomization of a High Speed Liquid Jet by Wall Impingement

TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series B ◽

10.1299/kikaib.71.978 ◽

2005 ◽

Vol 71 (703) ◽

pp. 978-985

Author(s):

Mikiya ARAKI ◽

Chengjun XU ◽

Seiichi SHIGA ◽

Hideshi YAMADA ◽

Shigeru HAYASHI ◽

...

Keyword(s):

High Speed ◽

Liquid Jet ◽

Wall Impingement

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Effect of Cross-Flow Swirl on the Trajectory of Spray in an Annular Passage

Journal of Engineering for Gas Turbines and Power ◽

10.1115/1.4049378 ◽

2020 ◽

Author(s):

Tushar Sikroria ◽

Abhijit Kushari

Keyword(s):

Momentum Flux ◽

High Speed ◽

Air Flow ◽

Cross Flow ◽

Flux Ratio ◽

Liquid Jet ◽

Swirl Number ◽

Flow Swirl ◽

Air Stream ◽

The Impact

Abstract This paper presents the experimental analysis of the impact of swirl number of cross-flowing air stream on liquid jet spray trajectory at a fixed air flow velocity of 42 m/s with the corresponding Mach number of 0.12. The experiments were conducted for 4 different swirl numbers (0, 0.2, 0.42 and 0.73) using swirl vanes at air inlet having angles of 0°, 15°, 30° and 45° respectively. Liquid to air momentum flux ratio (q) was varied from 5 to 25. High speed (@ 500 fps) images of the spray were captured and those images were processed using MATLAB to obtain the path of the spray at various momentum flux ratios. The results show interesting trends for the spray trajectory and the jet spread in swirling air flow. High swirling flows not only lead to spray with lower radial penetration due to sharp bending and disintegration of liquid jet, but also result in spray with high jet spread and spray area. Based on the results, correlations for the spray path have been proposed which incorporates the effects of the swirl number of the air flow.

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Comparison in High-Speed Droplet Impact Between Single and Multiple Collisions Against a Wall Covered With a Liquid Film

Volume 5: Multiphase Flow ◽

10.1115/ajkfluids2019-5200 ◽

2019 ◽

Author(s):

Yoichiro Fukuchi ◽

Tomoki Kondo ◽

Keita Ando

Keyword(s):

Shear Stress ◽

Wall Shear Stress ◽

High Speed ◽

Water Layer ◽

Liquid Jet ◽

Surface Erosion ◽

Single Droplet ◽

Cleaning Efficiency ◽

Droplet Impingement ◽

Wall Shear

Abstract In semiconductor industry, liquid jet cleaning plays an important role because of its high cleaning efficiency and low environmental load. However, its cleaning mechanism is not revealed in detail because the experimental observation of high-speed and sub-micron droplets is challenging. Furthermore, higher impact velocity may give rise to surface erosion due to water-hammer shock loading from the impingement. To study cleaning mechanisms and surface erosion, numerical simulation of droplet impingement accounting for both viscosity and compressibility is an effective approach. In the previous study, wall-shear-flow generation has evaluated from the simulation of high-speed single droplet impingement. To evaluate more practical model of jet cleaning application, simulation of two droplets simplifying mono-dispersed splay of droplet train is favorable. Here, we numerically simulated impingement of two droplets, which allows for evaluating water-hammer pressure and wall shear stress. We consider the case of two water droplets (200 μm in diameter) that collides continuously, at speed 50 m/s, at the inter-droplet distance from 250 to 400 μm, with a no-slip rigid wall covered with a water layer (100 μm in thickness). The simulation is based on compressible Navier-Stokes equations for axisymmetric flow and the mixture of two components appears in numerically diffusion interface expressed by the volume average and advection equation. The simulation is solved by finite-volume WENO scheme that can capture both shock waves and material interface. In our simulation, the impingement of second droplet impingement gain higher shear stress than the single droplet impingement. At the case that the inter-droplet distance is 300 μm, maximum shear stress is 30.22 kPa (at the second droplet impingement), which is much larger than at the first droplet impingement (8.42 kPa). This result indicates how the second droplet impingement make wall shear flow induced by first droplet impingement stronger. From the parameter study of the inter-droplet distance, we can say that wall shear stress gets stronger as water layer thickness decreases. Furthermore, the maximum wall pressure is 1.96 MPa at the second droplet impingement, which is larger than at the first droplet impingement (1.46 MPa). From this study, the evaluation of surface erosion caused by jet cleaning is expected. The simulation suggests that multiple droplets impingement continuously may gain higher cleaning efficiency, which will give us a fundamental insight into liquid jet cleaning technologies. For further study, simulation of water column impingement and comparing the result of impingement of two droplets are expected.

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Kinematics of vortex ring generated by a drop upon impacting a liquid pool

Journal of Fluid Mechanics ◽

10.1017/jfm.2019.503 ◽

2019 ◽

Vol 875 ◽

pp. 842-853 ◽

Cited By ~ 5

Author(s):

Abhishek Saha ◽

Yanju Wei ◽

Xiaoyu Tang ◽

Chung K. Law

Keyword(s):

Vortex Ring ◽

High Speed ◽

Morphological Evolution ◽

Laser Induced Fluorescence ◽

Liquid Pool ◽

Viscous Effects ◽

Penetration Process ◽

Pool Surface ◽

Three Stages ◽

Unified Description

We herein report an experimental study on the morphological evolution of a vortex ring formed inside a liquid pool after it is impacted and penetrated by a coalescing drop of the same liquid. The dynamics of the penetrating vortex ring along with the deformation of the pool surface has been captured using simultaneous high-speed laser induced fluorescence and shadowgraph techniques. It is identified that the motion of such a vortex ring can be divided into three stages, during which inertial, capillary and viscous effects alternatingly play dominant roles to modulate the penetration process, resulting in linear, non-monotonic and decelerating motion in these three stages respectively. Furthermore, we also evaluate the relevant time and length scales of these three stages and subsequently propose a unified description of the downward motion of the penetrating vortex ring. Finally, we use the experimental data for a range of drop diameters and impact speeds to validate the proposed scaling.

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