Influence of Position Initiation Error on Formation of New EFP

2012 ◽  
Vol 152-154 ◽  
pp. 860-865
Author(s):  
Feng Wang ◽  
Zhong Hua Du ◽  
Jie Dong Gao ◽  
Yu Cai Dong
Keyword(s):  
Numerical Simulation ◽  
Detonation Wave ◽  
Wave Front ◽  
Initial Phase ◽  
Great Influence ◽  
Collision Effect ◽  
Wave Collision ◽  
The Way

Position initiation error shows great influence on new EFP. It not only causes the way of crushed liner by detonation wave at initial phase, but also influences wave front to show asymmetric. Finally it influences detonation wave collision effect to make penetrator slope. The influence of position initiation error on new EFP was studied in numerical simulation. As increase of position initiation error, tilt trend shows faster. For different length of charge, position initiation error shows different collision effect. Position initiation error shows greater influence with smaller length charge than larger.

scholarly journals The Influence of Pipe Bending Curvature on H2-O2 Gaseous Detonation Wave Front

2021 ◽  
Vol 11 (9) ◽  
pp. 3951
Author(s):  
Hui Zhao ◽  
Huiyuan Li ◽  
Haitao Zhao ◽  
Leisheng Li ◽  
Jian Li
Keyword(s):  
Detonation Wave ◽  
Pressure Distribution ◽  
Wave Front ◽  
Cell Size ◽  
Chemical Reaction ◽  
Cellular Structure ◽  
Gaseous Detonation ◽  
External Boundary ◽  
Propagation Characteristics ◽  
Detonation Wave Front

The influence of different bend curvatures on the detonation wave propagation was analyzed by an advanced numerical simulation system. The mechanism of propagation properties is revealed by cellular structure, internal and external boundary pressure distribution, propagation process of detonation wave and chemical reaction. The cellular structure and detonation wave front of bend with different curvature are very different. The simulation results show that the detonation wave with regular cell structure propagating through the curved parts induces detonation cell size increased by diffraction near the inner wall while detonation reflected on the bottom surface resulting in decrease of cell size. Detonation wave was affected by the rarefaction wave and compression wave in the bent pipe. The pressure distribution of the bend shows that the peak pressure in the 450 curvature is the largest, which should be paid more attention in industrial design. The chemical reaction could indicate the propagation characteristics of detonation wave, and different propagation characteristics have different profiles of chemical components.

Structural Design and Forming Method of Single-Curved Surface Structure Based on Miura-Origami

2016 ◽  
Author(s):  
Hairui Wang ◽  
Chunfang Guo ◽  
Yujie Li ◽  
Yahua Liu ◽  
Minjie Wang ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Structural Design ◽  
High Efficiency ◽  
Circular Tube ◽  
Great Influence ◽  
Curved Surface ◽  
Structural Performance ◽  
Forming Process ◽  
Structural Support ◽  
Vacuum Forming

With the advantage of high adaptability, Miura-origami structure with curvature shows various engineering applications such as a sandwich between two stiff facings with curvature requirements and structural support to form a circular tube. In this research, a forming method of polymer circular tube with single-curved surface origami expressed by five parameters was established and its corresponding theory was solved considering forming rationality in actual manufacturing. The components of circular tube were fabricated by the vacuum forming process and then spliced together. We conducted numerical simulation to analyze the structural performance of the tube with five parameters and shown that these parameters have a great influence on energy absorbed performance. Finally, a male mold of a part with Arc Miura-origami structure was designed and fabricated. The parts with Arc Miura-origami were manufactured using vacuum forming process and then spliced and bonded together into a two-layer tube. This research may provide a method to design and fabricate Miura-origami structure with high efficiency and quality.

Numerical simulation of gas-solid two-phase reaction flow with multiple moving boundaries

2015 ◽  
Vol 25 (2) ◽  
pp. 375-390 ◽  
Author(s):  
Qiao Luo ◽  
Xiaobing Zhang
Keyword(s):  
Numerical Simulation ◽  
Physical Phenomenon ◽  
Great Influence ◽  
Moving Boundaries ◽  
Charge Weight ◽  
Phase Reaction ◽  
Two Phase ◽  
Content Type ◽  
One Dimensional ◽  
Chamber Volume

Purpose – In engineering applications, gas-solid two-phase reaction flow with multi-moving boundaries is a common phenomenon. The launch process of multiple projectiles is a typical example. The flow of adjacent powder chambers is coupled by projectile’s motion. The purpose of this paper is to study this flow by numerical simulation. Design/methodology/approach – A one-dimensional two-phase reaction flow model and MacCormack difference scheme are implemented in a computational code, and the code is used to simulate the launch process of a system of multiple projectiles. For different launching rates and loading conditions, the simulated results of the launch process of three projectiles are obtained and discussed. Findings – At low launching rates, projectiles fired earlier in the series have little effect on the launch processes of projectiles fired later. However, at higher launching rates, the projectiles fired first have a great influence on the launch processes of projectiles fired later. As the launching rate increases, the maximum breech pressure for the later projectiles increases. Although the muzzle velocities increase initially, they reach a maximum at some launching rate, and then decrease rapidly. The muzzle velocities and maximum breech pressures of the three projectiles have an approximate linear relationship with the charge weight, propellant web size and chamber volume. Originality/value – This paper presents a prediction tool to understand the physical phenomenon of the gas-solid two-phase reaction flow with multi-moving boundaries, and can be used as a research tool for future interior ballistics studies of launch system of multiple projectiles.

Numerical Simulation on the Regular Pattern of the Lateral Friction Transmission of the Pile in the Incline under the Pulling Force

2014 ◽  
Vol 501-504 ◽  
pp. 248-253
Author(s):  
Liu Yong Cheng ◽  
Shan Xiong Chen ◽  
Xi Chang Xu ◽  
Xiao Jie Chu ◽  
Tong Bing Lei
Keyword(s):  
Numerical Simulation ◽  
Bearing Capacity ◽  
Pile Foundation ◽  
Influence Factors ◽  
Great Influence ◽  
Regular Pattern ◽  
Slope Gradient ◽  
Pulling Force ◽  
Lateral Friction

The regular pattern of the lateral friction transmission is one of the most critical influences on the ultimate uplift bearing capacity. The pile foundation in the incline under the pulling force has a wide variety of characteristics which is different with the normal pile. Numerical simulation is done by the use of FLAC3D in this paper. The regular pattern of the lateral friction transmission of the pile in the incline under the pulling force is studied. And the influence factors on the lateral friction transmission such as the slope gradient, the length and location of piles are discussed. The results show that the incline has a great influence on the lateral friction transmission. The lateral friction which is away from the incline-side is about 30% to 50% bigger than the incline-side. The slope gradient and the location of piles all have a great influence on the lateral friction transmission.

Contrast Study on the Radial Velocity of the Flow Field of the Hydrocyclones with Different Inlet Structures

2011 ◽  
Vol 339 ◽  
pp. 624-629
Author(s):  
Lian Cheng Ren ◽  
Zheng Liang ◽  
Jiang Meng ◽  
Lin Yang ◽  
Jia Lin Tian
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Radial Velocity ◽  
Axial Symmetry ◽  
Separation Efficiency ◽  
Great Influence ◽  
The Other ◽  
Contrast Study ◽  
The One ◽  
Tangential Inlet

On the base of numerical simulation and theoretical analysis, the flow field of a conventional single-tangential-inlet Hydrocyclone and a newly put forward axial-symmetry double-tangential-inlet hydrocyclone were contrasted. The study shows that the inlet structure of the Hydrocylone has a great influence on the radial velocity of the flow field in the hydrocyclone and that the radial velocity in the hydrocyclone with single-tangential-inlet is not symmetry about the axis of the hydrocyclone; and on the other hand the radial velocity in the hydrocyclone with axial-symmetry double-tangential-inlet is symmetry about the axis of the hydrocyclone. The magnitude of the radial velocity of the flow in the hydrocyclone with single-tangential-inlet is greater than that in the hydrocyclone with axial-symmetry double-tangential-inlet hydrocyclone, which means the hydrocyclone with axial-symmetry double-tangential-inlet has greater capability than the rival one with single-tangential inlet. The symmetry about the axis of the hydrocyclone of the radial velocity means the radial velocities in the place where the radio is the same are constant, which means the hydrocyclone has a great separation efficiency. The conclusion is that changing the conventional hydrocyclone into the one with axial-symmetry double-tangential-inlet structure can offer greater separation capability and efficiency.

Gaseous detonation propagation in a bifurcated tube

2008 ◽  
Vol 599 ◽  
pp. 81-110 ◽  
Author(s):  
C. J. WANG ◽  
S. L. XU ◽  
C. M. GUO
Keyword(s):  
Numerical Simulation ◽  
Detonation Wave ◽  
Mach Reflection ◽  
Initial Pressure ◽  
Gaseous Detonation ◽  
Recirculation Region ◽  
Horizontal Branch ◽  
Regular Reflection ◽  
Detonation Propagation ◽  
Wall Geometry

Gaseous detonation propagation in a bifurcated tube was experimentally and numerically studied for stoichiometric hydrogen and oxygen mixtures diluted with argon. Pressure detection, smoked foil recording and schlieren visualization were used in the experiments. Numerical simulation was carried out at low initial pressure (8.00kPa), based on the reactive Navier–Stokes equations in conjunction with a detailed chemical reaction model. The results show that the detonation wave is strongly disturbed by the wall geometry of the bifurcated tube and undergoes a successive process of attenuation, failure, re-initiation and the transition from regular reflection to Mach reflection. Detonation failure is attributed to the rarefaction waves from the left-hand corner by decoupling leading shock and reaction zones. Re-initiation is induced by the inert leading shock reflection on the right-hand wall in the vertical branch. The branched wall geometry has only a local effect on the detonation propagation. In the horizontal branch, the disturbed detonation wave recovers to a self-sustaining one earlier than that in the vertical branch. A critical case was found in the experiments where the disturbed detonation wave can be recovered to be self-sustaining downstream of the horizontal branch, but fails in the vertical branch, as the initial pressure drops to 2.00kPa. Numerical simulation also shows that complex vortex structures can be observed during detonation diffraction. The reflected shock breaks the vortices into pieces and its interaction with the unreacted recirculation region induces an embedded jet. In the vertical branch, owing to the strength difference at any point and the effect of chemical reactions, the Mach stem cannot be approximated as an arc. This is different from the case in non-reactive steady flow. Generally, numerical simulation qualitatively reproduces detonation attenuation, failure, re-initiation and the transition from regular reflection to Mach reflection observed in experiments.

scholarly journals Analysis of a self-centring detonation wave generator

2021 ◽  
pp. 34-47
Author(s):  
Waldemar Trzciński ◽  
Józef Paszula ◽  
Leszek Szymańczyk
Keyword(s):  
Theoretical Analysis ◽  
Detonation Wave ◽  
Wave Front ◽  
Point Location ◽  
Wave Fronts ◽  
Initiation Point ◽  
X Ray ◽  
Detonation Wave Front ◽  
Main Charge ◽  
Wave Generator

The aim of the study was to determine the parameters of a detonator generating a self-centring detonation wave, based on experimental and theoretical analysis. The methods for manufacturing selfcentring detonation wave generators available in literature were reviewed and a detonator comprised of two explosives was proposed. The detonator geometry was analysed for its ability to centre the detonation wave. A physical detonator model was created and the detonation wave front downstream of the detonator, analysed and the detonator’s capability to compensate an off-centre detonation initiation, evaluated. The wave fronts were recorded using pulsed x-ray radiography. The study showed that the proposed detonator provides a symmetrical initiation of the main charge for the initiation point (location) offset, lower than the assumed maximum offset.

scholarly journals Początki kształtowania się reprezentacji społecznej zapożyczeń w sferze publicznej

2019 ◽  
Vol 27 ◽  
pp. 29-41
Author(s):  
Piotr Zbróg
Keyword(s):  
Public Sphere ◽  
Common Sense ◽  
Initial Phase ◽  
Native Language ◽  
Social Representations ◽  
16Th Century ◽  
The Public ◽  
Methodological Basis ◽  
The Public Sphere ◽  
The Way

The beginnings of the shaping of social representations of borrowings in the public sphereThe article presents an initial phase of the process of shaping of social representations of borrowings. The aim was to obtain a view of the way in which participants of the public sphere talked about these elements of language, how they perceived them as well as what common sense image was created on this basis in the communication sphere and how it was modified. The first judgements and opinions on the matter of foreign words appeared around the 16th century and evolved from that moment. The theory of social representations developed by Serge Moscovici was applied as a theoretical and methodological basis of the description. Its research tools allow us to see the way in which societies construct meanings of matters important to them. On the basis of the analysis of the material it was established that from the beginning there were rather antagonistic elements of social representations of borrowings. The functionality of borrowings was noticed. Yet it was postulated that they should be eliminated from texts on account of the necessity to develop the native language, the incomprehensibility of statements as well as the excessive trend of foreignness.

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