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Defence Technology(防务技术) 2025年第1期43卷 120-141页

作者： Changjiang Liu Hujun Li Zhen Wang Yong He Guokai Zhang Mingyang Wang School of Mechanical Engineering Nanjing University of Science and TechnologyNanjing 210094China State Key Laboratory of Disaster Prevention and Mitigation of Explosion and Impact People's Liberation Army Engineering UniversityNanjing 210014China

Traffic engineering such as tunnels in various altitudinal gradient zone are at risk of accidental explosion,which can damage personnel and *** prediction of the distribution pattern of explosive loads and shock wave propagation process in semi-enclosed structures at various altitude environment is key research focus in the fields of explosion shock and fluid *** effect of altitude on the propagation of shock waves in tunnels was investigated by conducting explosion test and numerical *** on the experimental and numerical simulation results,a prediction model for the attenuation of the peak overpressure of tunnel shock waves at different altitudes was *** results showed that the peak overpressure decreased at the same measurement points in the tunnel entrance under the high altitude *** contrast,an increase in altitude accelerated the propagation speed of the shock wave in the *** average error between the peak shock wave overpressure obtained using the overpressure prediction formula and the measured test data was less than15%,the average error between the propagation velocity of shock waves predicted values and the test data is less than 10%.The method can effectively predict the overpressure attenuation of blast wave in tunnel at various altitudes.

关键词： shock wave propagation Tunnel Altitude effect Peak overpressure shock waves velocity Engineering safety

Research on the collapse process of a near-wall bubble

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Journal of Hydrodynamics 2023年第5期35卷 899-912页

作者： Bing Zhu Wang Han Wen-jun Xu Wei Zhang University of Shanghai for Science and Technology Shanghai200093China Shanghai Key Laboratory of Power Energy in Multiphase Flow and Heat Transfer Shanghai200093China Marine Design and Research Institute of China Shanghai200011China

The effect of wall on the bubble collapse is significant. A compressible numerical simulation method based on the state equation was used to numerically calculate the collapse process of bubbles at different leaving wall distances. The results show that when the dimensionless distance between the bubble center and the wall is greater than zero, the bubble generates a high-pressure region at the top of the interface, which induces a jet toward the wall. When the dimensionless distance is less than zero, the jet is generated from the vicinity of the contact position between the bubble and the wall and moves along the wall towards the center axis of the bubble. When the dimensionless distance is equal to zero, that is, the center of the bubble coincides with the center of the wall, the bubble shrinks uniformly, and its collapse process is consistent with that of a single bubble in free space under the same parameter conditions. Comparison of these three typical cases of dimensionless distance from the wall reveals that the presence of the wall induces an asymmetric effect and a pressure gradient effect in the flow field around the bubble, and the farthest point away from the center of the attached wall is a high-pressure region, which induces destabilization of the bubble interface and the occurrence of jets.

关键词： Bubble collapse compressible simulation shock wave propagation jet flow direction

Insights into microstructural evolution and deformation behaviors of a gradient textured AZ31B Mg alloy plate under hypervelocity impact

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Journal of Materials Science & Technology 2021年第32期91卷 40-57页

作者： Weigui Zhang Kun Li Runqiang Chi Susheng Tan Peijie Li Beijing Innowind Aerospace Equipment Co. Ltd.Beijing 100854China College of Mechanical and Vehicle Engineering Chongqing UniversityChongqing 400044China The State Key Lab of Mechanical Transmissions Chongqing UniversityChongqing 400044China Hypervelocity Impact Research Center Harbin Institute of TechnologyHarbin 150080China Department of Electrical and Computer Engineering and Petersen Institute of Nanoscience and Engineering University of PittsburghPittsburghPennsylvania 15260USA Department of Mechanical Engineering Tsinghua UniversityBeijing 100084China

We have for the first time elucidated the microstructural evolution and deformation behaviors of a gradient textured AZ31 B Mg alloy plate under the ultrahigh strain rate of ~10~6 s^(-1) that is generated by a two-stage light gas gun with the hypervelocities of 1.6-4.4 km s^(-1). The hypervelocity impact cratering behaviors indicate that the cratering deformation of AZ31 B Mg alloy is mainly affected by the inertia and strength of the target material. The crater prediction equation of AZ31 B Mg alloy target under impact velocity of 5 km s^(-1) is given. The 2017 Al projectile completely melts in the Mg alloy target plate at the impact velocities of 3.8 km s^(-1) and 4.4 km s^(-1), and the microstructural evolution around the crater is: dynamic recrystallization zone, high-density twinning zone, low-density twinning zone, and Mg alloy matrix. It is found that the dynamic recrystallization, twinning and cracking are the main deformation behaviors for the AZ31 B Mg alloy to absorb the shock wave energy and release the stress generated by the hypervelocity impact. The main plastic deformation mechanisms of the Mg alloy target during hypervelocity impact are twinning and dislocation slip. Microstructure analysis shows the interactions of twins-twins, dislocations-dislocations, and twins-dislocations determine the strain hardening during the hypervelocity impact process, which eventually contributes the dynamic mechanical properties. The evolution of microhardness around the crater further demonstrates the microstructural evolutions and their interactions under the hypervelocity impacts.

关键词： AZ31B Mg alloy plate Hypervelocity impact Deformation behavior shock wave propagation Microstructural evolution

Blast waveform tailoring using controlled venting in blast simulators and shock tubes

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Defence Technology（防务技术） 2024年第7期37卷 14-26页

作者： Edward Chern Jinn Gan Alex Remennikov David Ritzel Faculty of Engineering and Information Sciences University of WollongongWollongongNSW2522Australia Dyn-FX Consulting Ltd 19 Laird Ave NorthAmherstburgONN9V 2T5Canada

A critical challenge of any blast simulation facility is in producing the widest possible pressure-impulse range for matching against equivalent high-explosive *** tubes and blast simulators are often constrained with the lack of effective ways to control blast wave profiles and as a result have a limited performance *** wave shaping techniques employed in some facilities are reviewed but often necessitate extensive geometric modifications,inadvertently cause flow anomalies,and/or are only applicable under very specific *** paper investigates controlled venting as an expedient way for waveforms to be tuned without requiring extensive modifications to the driver or existing geometry and could be widely applied by existing and future blast simulation and shock tube *** use of controlled venting is demonstrated experimentally using the Advanced Blast Simulator(shock tube)at the Australian National Facility of Physical Blast Simulation and via numerical flow simulations with Computational Fluid *** venting is determined as an effective method for mitigating the impact of re-reflected waves within the blast *** control method also allows for the adjustment of parameters such as tuning the peak overpressure,the positive phase duration,and modifying the magnitude of the negative phase and the secondary shock of the blast *** paper is concluded with an illustration of the potential expanded performance range of the Australian blast simulation facility when controlled venting for blast waveform tailoring as presented in this paper is applied.

关键词： Advanced blast simulator shock wave propagation Far-field explosion Blast loads Blast waves Computational fluid dynamics

Numerical Simulation of Flow Characteristics in Micro shock Tubes

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Journal of Thermal Science 2015年第3期24卷 246-253页

作者： Guang Zhang Toshiaki Setoguchi Heuy Dong Kim Department of Mechanical Engineering Andong National University Department of Mechanical Engineering Saga University

Recently micro shock tubes have been widely used in many engineering and industrial fields, but the characteristics of unsteady flow are not well known to date in micro shock tubes. Compared to conventional shock tubes with macro scales, flows related to shock waves in micro shock tubes are highly complicated. Stronger viscous and dissipative interactions make shock wave dynamic behaviors significantly different from theoretical predictions. In the present study, a CFD work was applied to the unsteady compressible Navier-Stokes equations which were solved using a fully implicit finite volume scheme. The diaphragm pressure ratio and shock tube diameter were varied to investigate their effects on micro shock tube flows. Different wall boundary conditions were also performed to observe shock wave and contact surface propagation with no slip and slip walls. Detailed flow characteristics at the foot of shock wave and contact surface propagation were known from the present numerical simulations.

关键词： Micro shock tube shock wave propagation Slip wall Unsteady flow CFD

Near-source characteristics of two-phase gas-solid outbursts in roadways

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International Journal of Coal Science & Technology 2021年第4期8卷 685-696页

作者： Aitao Zhou Meng Zhang Kai Wang Derek Elsworth Beijing Key Laboratory for Precise Mining of Intergrown Energy and Resources China University of Mining and Technology(Beijing)Beijing 100083China School of Emergency Management and Safety Engineering China University of Mining and Technology(Beijing)Beijing 100083China Department of Energy and Mineral Engineering EMS Energy Institute and G3 CenterPennsylvania State UniversityUniversity ParkPAUSA

Coal and gas outbursts compromise two-phase gas-solid mixtures as they propagate as shock waves and flows from their *** is influenced by the form of the outburst,proximity to source,the structure and form of the transmitting roadways and the influence of *** following characterizes the propagation of coal and gas outbursts as two-phase gas-solid flows proximal to source where the coupled effects of pulverized coal and gas flows dominate *** characteristics of shock wave propagation and attenuation were systematically examined for varied roadway geometries using experiments and numerical *** results demonstrate that the geometry of roadway obstructions is significant and may result in partial compression and sometimes secondary overpressurization in blocked and small comer roadways leading to significant attenuation of outburst shock *** shock waves attenuate slowly in both straight and abruptly expanding roadways and more significantly in T-shaped *** most significant attenuation appears in small angle comers and bifurcations in roadways with the largest attenuation occurring in blocked *** results provide basic parameters for simplifying transport in complex roadway networks in the far-field,and guidance for the design of coal and gas outburst prevention facilities and emergency rescue.

关键词： Coal and gas outburst Proximity to source shock wave propagation Two-phase gas-solid flow Outburst prevention

An improve d smoothe d particle hydrodynamics approach using new inverse kernel function

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Journal of Ocean Engineering and Science 2022年第4期7卷 327-336页

作者： J.R.Rajapriyadharshini Department of Civil Engineering Thiagarajar College of EngineeringMaduraiTNIndia

The main limitation of Smoothed Particle Hydrodynamics(SPH)method that resists the method’s poten-tial is its lack of providing stability and accuracy to the numerical *** improve the accuracy of the standard SPH technique,by formulating a new inverse logarithmic kernel *** new kernel function is derived based on the underlying properties of kernel *** approximation technique used here is based on the Moving Least Squares based *** adequacy of the proposed ker-nel function is tested by simulation of 2D shock wave propagation and 3D dam-break free surface flow against a cuboidal *** method was validated against experimental data by Kleefsman et al.,[1].The numerical results reveal that our new SPH approach using inverse logarithmic kernel function outper-forms existing ones in particle restoration,zero error,better accuracy and enhanced efficiency in kernel *** new kernel function showed some improvement over existing kernels by showing very less error approximation value of 0.035h *** results showed some improvements over standard technique by being capable of handling problems with large deformations accurately and precisely.

关键词： Inverse logarithmic function Moving least squares approximation shock wave propagation 3D dam-break flow Zero error