Cavity collapse in a liquid with solid particles

1994 ◽  
Vol 259 ◽  
pp. 149-165 ◽  
Author(s):  
N. K. Bourne ◽  
J. E. Field
Keyword(s):  
Shock Front ◽  
Solid Particle ◽  
High Speed ◽  
Thin Sheet ◽  
Weak Shock ◽  
Incident Shock ◽  
Solid Particles ◽  
Cavity Collapse ◽  
Collapse Time ◽  
Axis Parallel

An experimental study of the interaction of weak shock waves in a liquid with bubbles and solid particles has been conducted. Cavities were punched, and solid particles were cast, into a thin sheet of gelatine clamped between two transparent blocks. A shock of pressure 0.3 GPa was introduced by impacting the gelatine layer with a flyer plate. The subsequent collapse of the cavities was photographed using high-speed framing cameras, and waves in the gelatine were visualized using schlieren optics. Assorted cavity/particle geometries were studied. In the first, cavity and particle were aligned on an axis parallel to the incident shock front. The jet crossing the cavity was found to deviate from the perpendicular to the shock front. This deviation was towards the solid particle when separations were small and away from the particle when separations were increased. When a cavity was placed upstream of a solid particle the collapse time was reduced. Conversely, when a cavity was placed downstream of a solid particle, collapse time was increased and the closure was more symmetrical. These observations were explained in terms of wave reflections. Collapses where the cavity/particle axis was inclined to the incident shock showed features of each of the geometries described above.

scholarly journals Atomization of Gel Fuels with Solid Particle Addition Utilizing an Air Atomizing Nozzle

Energies ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2959
Author(s):  
Yunlei Xiao ◽  
Zhixun Xia ◽  
Liya Huang ◽  
Likun Ma ◽  
Dali Yang
Keyword(s):  
Mass Flow Rate ◽  
Solid Particle ◽  
Mass Flow ◽  
Flow Rate ◽  
High Speed ◽  
Droplet Diameter ◽  
Aluminum Particle ◽  
Solid Particles ◽  
Particle Content ◽  
Boron Particle

Microscopic high-speed imaging is used to experimentally measure the velocity and size of droplets of gelled RP-1 based fuels with a solid particle additive. The gels are atomized using an air atomizing nozzle. The droplet diameter and velocity at a fixed position 20 cm from the nozzle on the centerline of the spray are measured at air mass flow rates of 1.5, 3 and 5 g/s. A parametric study is conducted to study the effect of gas mass flow rate, boron particle content, and species of the solid particle on the droplet characteristics. The results indicate that the droplet size decreases with the increasing of gas mass flow rate and boron particle content. Gel fuels with an aluminum particle are observed to produce smaller droplets at a low gas mass flow rate than that with a boron particle. The implication of these observations is that the atomization processes for gelled fuels with an additive of solid particles is controlled by the velocity difference between the gas and the droplets.

Detonation Studies in Dispersed Solid Particulate Explosives Using High Speed Time-Resolved Holography

1992 ◽  
Vol 296 ◽  
Author(s):  
Michael J. Ehrlich ◽  
James W. Wagner ◽  
Jacob Friedman ◽  
Heinrich Egghart
Keyword(s):  
Shock Wave ◽  
Convective Flow ◽  
High Speed ◽  
Liquid Fuel ◽  
Similar Case ◽  
Incident Shock ◽  
Solid Particles ◽  
Liquid Droplets ◽  
Time Resolved ◽  
Individual Particles

IntroductionClouds of dispersed explosive or combustible solid particles are detonable and such systems may exhibit self-sustained detonation [1–8]. However, the method by which individual particles in the explosive cloud interact to sustain detonation is not well understood. The similar case of liquid fuel/air explosives was investigated in detail during the 1960's and 1970's. For these systems, it was established that incident shock waves serve to shatter large liquid droplets into a mist of micro-droplets. These microdroplets are almost instantaneously accelerated to the convective flow velocity behind the shock wave. The energy released upon ignition of the micromist supports the shock wave and selfsustained detonation results [9–11].

scholarly journals Experimental Application of the Process Industry Solid Particle�s Displacement in a Vertical air Flow

2020 ◽  
Vol 71 (6) ◽  
pp. 9-21
Author(s):  
Mirela Panainte-Lehadus ◽  
Emilian-Florin Mosnegutu ◽  
Valentin Nedeff ◽  
Narcis Barsan ◽  
Dana Chitimus ◽  
...  
Keyword(s):  
Angular Velocity ◽  
Solid Particle ◽  
High Speed ◽  
Average Velocity ◽  
Air Flow ◽  
Experimental Studies ◽  
Video Camera ◽  
Solid Particles ◽  
Physical Parameters ◽  
Software Methodology

In this article some experimental studies were performed in order to analyze some physical parameters specific for a solid particle during displacement in a vertical air flow. The analyzed parameters were the instantaneous average velocity value and the angular velocity value. To determine the two parameters, a laboratory stand was used for the aerodynamic separation of a mixture of solid particles and a high-speed video camera in order to be able to track the behaviour of the studied particles. At the same time, a working methodology has been designed, implying the use of multiple software, i.e. analysis, video, imagistic and date software, methodology that aims to convert a video file, where we have a 2D view, into a 3D interpretation. Following the analysis of the obtained results, we noticed that both the instantaneous average velocity value and the angular velocity value are closely linked to the sphericity of the solid particle, varying inversely proportional to it, and to the air flow velocity, which directly influences the analyzed parameters.

Penetration Dynamics of Solid Particles into Liquids High-Speed Experimental Results and Modelling

2005 ◽  
Vol 473-474 ◽  
pp. 429-434 ◽  
Author(s):  
Olga Verezub ◽  
György Kaptay ◽  
Tomiharu Matsushita ◽  
Kusuhiro Mukai
Keyword(s):  
Contact Angle ◽  
Particle Size ◽  
Aqueous Solutions ◽  
Particle Velocity ◽  
Weber Number ◽  
High Speed ◽  
Solid Particles ◽  
Bulk Liquid ◽  
Distilled Water ◽  
Critical Weber Number

Penetration of model solid particles (polymer, teflon, nylon, alumina) into transparent model liquids (distilled water and aqueous solutions of KI) were recorded by a high speed (500 frames per second) camera, while the particles were dropped from different heights vertically on the still surface of the liquids. In all cases a cavity has been found to form behind the solid particle, penetrating into the liquid. For each particle/liquid combination the critical dropping height has been measured, above which the particle was able to penetrate into the bulk liquid. Based on this, the critical impact particle velocity, and also the critical Weber number of penetration have been established. The critical Weber number of penetration was modelled as a function of the contact angle, particle size and the ratio of the density of solid particles to the density of the liquid.

Simulation of Impaction Between Liquid Droplet and Solid Particles Based on SPH Method

2014 ◽  
Author(s):  
Shuai Meng ◽  
Qian Wang ◽  
Rui Yang
Keyword(s):  
Surface Tension ◽  
Solid Particle ◽  
Liquid Droplet ◽  
Particle Interaction ◽  
Solid Particles ◽  
Seed Particle ◽  
Liquid Droplets ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Spray Granulation

The phenomenon of impaction between liquid droplets and solid particles is involved in many scientific problems and engineering applications, such as impaction between sprayed droplet and solid particles in limestone injection desulfurization system and the collision between a droplet of the liquid to be granulated and a seed particle in fluidized bed spray granulation process. There are a lot of factors affected this phenomenon: droplet and particle size, momentum of both liquid droplet and solid particles, materials, surface conditions of the solid particles and so on. However the experimental or numerical researches have been done mostly pay attention to Specific application or process, so the impaction phenomenon has not been through studied, for example how different factors affected the impaction process with its effect on different applications. This paper focuses on the basic issue of interaction between droplet and solid particles. Three main factors were considered: ratio of diameter between the droplet and solid particle, relative velocity and the surface tension (including the contact angle between droplet and solid particle). All the study is based on simulation using SPH (smoothed particle hydrodynamics) method, and the surface tension is simulated by particle-particle interaction.

Morphology of Edge Cracks of Rolled Magnesium Alloy Sheet

2014 ◽  
Vol 922 ◽  
pp. 469-474 ◽  
Author(s):  
Sho Manabe ◽  
Hiroshi Utsunomiya ◽  
Tetsuo Sakai ◽  
Ryo Matsumoto
Keyword(s):  
Magnesium Alloy ◽  
Magnesium Alloys ◽  
High Speed ◽  
Heating Temperature ◽  
Thin Sheet ◽  
Contact Length ◽  
Alloy Sheet ◽  
Different Temperatures ◽  
Edge Cracks ◽  
Critical Reduction

Magnesium alloys show low deformability at low temperature because of hcp structure and inactiveness of basal slip. Manufacturing of thin sheet is difficult in industries. Some approaches, such as small-draft multi-pass rolling, intermediate annealing, isothermal rolling and high-speed rolling were proposed to overcome the deformability. However, small edge cracks are still formed on the sheet. In this study, rolling speed of 1000m/min was employed to warm-roll AZ31B magnesium alloy in a single pass at different temperatures. The edge cracks formed after the rolling were classified into three main groups: minor, regular and zigzag edge cracks. ‘Crack contact length’ are introduced to explain the morphology of edge cracks. The results show that the critical reduction for crack initiation depends on the pre-heating temperature. The spacing between edge cracks increases linearly with the crack contact length regardless of roll diameter, speed and reduction. It is suggested that this approach is useful to understand the formation mechanism of edge cracks and to evaluate the rollability of magnesium alloys.

A Model for the Effect of Velocity on Erosion of N80 Steel Tubing due to the Normal Impingement of Solid Particles

1992 ◽  
Vol 114 (1) ◽  
pp. 54-64 ◽  
Author(s):  
D. P. Chase ◽  
E. F. Rybicki ◽  
J. R. Shadley
Keyword(s):  
Solid Particle ◽  
Computational Study ◽  
Target Material ◽  
Target Surface ◽  
American Petroleum Institute ◽  
Solid Particles ◽  
Unknown Coefficient ◽  
Conservation Of Energy ◽  
Carrier Fluid ◽  
Erosion Behavior

As part of a combined experimental and computational study of erosion for gas and oil production conditions, a semi-empirical model has been developed to predict erosion ratio behaviors of metals due to solid particle impingement. One use of the model will be to reduce the total number of experiments needed to characterize erosion behavior. The model represents material property information associated with both the target material and the impinging particles, as well as impingement speed. Five different models are examined in terms of ability to predict erosion ratio behavior as a function of impingement speed. The model selected is based on a conservation of energy formulation and fracture mechanics considerations to predict the amount of material removed due to solid particle impingement. The resulting equation to predict the erosion ratio for a given particle size contains one unknown coefficient which is determined through comparison with experimental data. Illustrative examples are presented for data for two different sizes of glass bead solid particles in an oil carrier fluid impinging on an API (American Petroleum Institute) N80 grade steel target at an impingement angle 90 deg to the target surface. Using erosion data at one impingement speed to determine the unknown coefficient, the model was used to predict erosion behavior at a range of other speeds. Good agreement between the erosion ratio data and the values predicted by the model were found for two solid particle sizes. Recommendations for expanding the capabilities of the model are pointed out.

Effective Stripper-Holding on High Speed Precision Blanking of Electronic Machine Parts

2005 ◽  
Vol 6-8 ◽  
pp. 805-808
Author(s):  
F. Sekine
Keyword(s):  
Mechanical Model ◽  
High Speed ◽  
Thin Sheet ◽  
Dimensional Accuracy ◽  
New Method ◽  
Important Process ◽  
Sheet Metals ◽  
Progressive Dies ◽  
Machine Parts

The blanking of thin sheet metals using progressive dies is an important process on production of precision electronic machine parts. As a model of IC leadframe, an I-shaped and an Lshaped models were blanked and influences of blanking conditions on dimensional accuracy of blanked lead were examined. Furthermore, a mechanical model is proposed to explain the affect of the blanking conditions on product accuracy. In these days, more fine leads are required as electronic machines become more precise and accurate. It must be treated that leads are firmly held for blanking leadframes accurately. In this paper, an effective method of stripper holding leads strongly are discussed and a new method using newly designed stripper is proposed. Consequently the effect of it on lead accuracy is proved.

scholarly journals DESIGN OF A MOBILE BIO-DIESEL PRODUCTION FACILITY

2011 ◽  
Author(s):  
B. J. Drake ◽  
M. Jacques ◽  
D. Binkley ◽  
S. Barghi ◽  
R. O. Buchal
Keyword(s):  
Particulate Matter ◽  
Vegetable Oil ◽  
Diesel Fuel ◽  
High Speed ◽  
Solid Particles ◽  
Vacuum Filter ◽  
Production Facility ◽  
Operational Life ◽  
Used Vegetable Oil ◽  
Diesel Production

In 2004/2005, a team of mechanical engineering students undertook an interdisciplinary capstone design project to design a mobile bio-diesel production facility capable of converting 500 L/h of used vegetable oil or animal tallow into bio-diesel fuel. Bio-diesel fuel has negligible sulfur content and significantly reduces the emission of particulate matter, e.g. soot and carbon monoxide, compared to the combustion of conventional diesel fuel. Furthermore, bio-diesel fuel is biodegradable, nontoxic, and can be produced from renewable feedstock. The mobile facility is capable of taking used vegetable oil from different sources and processing the oil while in motion, eliminating costs associated with transportation, land use and construction. A special filter was designed to remove any major particulate matter as well as wax-like substances formed by heating of the cooking oil during its operational life. A rotary vacuum filter was designed to continuously of remove wax and solid particles accumulated on the filter cloth. The wax and solid wastes, which are organic compounds, are readily converted to useful light organic molecules through a subsequent gasification process. A transesterification process was applied using methanol as a solvent and sodium hydroxide as a catalyst. A mix of unrefined bio-diesel fuel and glycerol, which is produced by transestrification, is sent to a glycerol separating tower. The separator was designed to efficiently separate bio-diesel fuel from glycerol. The bio-diesel fuel is neutralized by weak acid solution and washed by water to remove impurities. High-speed mixers were designed to create maximum contact between phases for efficient separation. The mobile facility is subject to vibration, which was considered in every aspect of the design. The facility will be powered by bio-diesel fuel, and heat recovery and water recycling were considered to minimize energy requirements. The project culminated in a final design report containing detailed engineering analysis and a comprehensive set of working drawings.

scholarly journals Effect of nano-solid particles on the mechanical properties of shear thickening fluid (STF) and STF-Kevlar composite fabric

2021 ◽  
Vol 16 ◽  
pp. 155892502110448
Author(s):  
Mingmei Zhao ◽  
Jinqiu Zhang ◽  
Zhizhao Peng ◽  
Jian Zhang
Keyword(s):  
Mechanical Properties ◽  
High Speed ◽  
Split Hopkinson Pressure Bar ◽  
Tensile Force ◽  
Shear Thickening ◽  
Solid Particles ◽  
Time Range ◽  
Shear Thickening Fluid ◽  
Pull Out ◽  
Diamond Particles

To analyze the effect of nano-solid particles on the mechanical properties of shear thickening fluid (STF) and its Kevlar composite fabric. In this study, nano-silica and polyethylene glycol (PEG 200) were used as dispersed and continuous phases. Nano-graphite and nano-diamond particles were used as additives to prepare STF and Kevlar composite fabric. Study the friction characteristics and rheological characteristics of STF at different temperatures. Explore the STF’s mechanical response under transient high-speed impact conditions through the split Hopkinson pressure bar experiment. The mechanical properties of STF-Kevlar fabric are studied through yarn pull-out test and burst experiments. The experimental results show that the intermolecular repulsive force of STF is enhanced under a high-temperature environment, and shear thickening effect is reduced. Nano-diamond particles strengthen the contact coupling force and contact probability between the particle clusters, so that the maximum viscosity of the system reaches 1679 Pa s, the thickening ratio reaches 318 times, and the rheological properties of the shear thickening fluid are improved. The results of the SHPB experiment show that the STF can complete a dynamic response within a 50–75 µs time range, and the maximum stress can reach 78 MPa. The bullet’s incident kinetic energy is not only transformed into thermal energy and phase change energy of solid-liquid conversion, but also into frictional energy between particles. The mechanical experiments of STF-Kevlar composite fabrics show that the tensile force value of STF5-Kevlar is the largest (10.3 N/13.5 N), and the tensile force of neat Kevlar was the smallest (4.3 N/4.9 N). The maximum bearing capacity (0.3 kN) and absorption energy (51.8 J) of Neat Kevlar are less than those of STF1-Kevlar (3.2 kN, 116.7 J) and STF3-Kevlar (1.9 kN, 88.2 J), and STF5-Kevlar (4.7 kN, 143.3 J). Fabric’s failure mode is converted from partial yarn extraction to overall deformation and rupture of the fabric. Therefore, by changing the solid additives’ parameters, the STF and the composite fabric’s mechanical properties can be effectively controlled, which provides a reference for preparing the STF and fabric composite materials.

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