scholarly journals Wind-Tunnel Studies on Sand Sedimentation Around Wind-Break Walls of Lanxin High-Speed Railway II and Its Prevention

2021 ◽  
Vol 11 (13) ◽  
pp. 5989
Author(s):  
Hongchao Dun ◽  
Guowei Xin ◽  
Ning Huang ◽  
Guangtian Shi ◽  
Jie Zhang
Keyword(s):  
Wind Tunnel ◽  
Deposition Rate ◽  
High Speed ◽  
Particle Deposition ◽  
Sand Particle ◽  
Gobi Desert ◽  
Strong Wind ◽  
Number Density ◽  
High Speed Railway ◽  
Sand Particles

Wind-break walls along Lanxin High-Speed Railway II were studied and approved as effective measures to reduce strong wind damage to the high-speed trains. The results show that sand sedimentation on the leeward sides of wind-break walls along the railway within Gobi Desert could significantly threaten the operation safety of running trains. Different from the current sand sedimentation prevention measures without adequate consideration of the deposition process of airborne sand particles, this study revealed the mechanism of sand sedimentation on the leeward sides of three wind-break walls within different terrains. A series of wind-tunnel experiments were carried out to measure the horizontal velocity, number density, transport flux, and deposition rate of sand particles, and it was found that the horizontal speed of sand particles was first increased and then decreased on the railway track, and the peak speed over the concave subgrade was much smaller than those over convex and flat subgrades. The number density and horizontal sand flux were largest over the concave subgrade, and were the smallest over the convex subgrade. The sand particle deposition rate and distribution were also the largest within the concave subgrade, and some measures were also proposed to prevent sand sedimentation on the leeward sides of wind-break walls.

Influence of Pipeline Inclination on Hydraulic Conveying of Sand Particles

2012 ◽  
Author(s):  
Ahmed Mohamed Nossair ◽  
Peter Rodgers ◽  
Afshin Goharzadeh
Keyword(s):  
Particle Transport ◽  
High Speed ◽  
Sand Dune ◽  
Sand Particle ◽  
Hydrocarbon Production ◽  
Production Wells ◽  
Load Transport ◽  
Bed Load Transport ◽  
Sand Particles ◽  
Dune Dynamics

The understanding of sand particle transport by fluids in pipelines is of importance for the drilling of horizontal and inclined hydrocarbon production wells, topside process facilities, infield pipelines, and trunk lines. Previous studies on hydraulic conveying of sand particles in pipelines have made significant contributions to the understanding of multiphase flow patterns, pressure drop and particle transport rate in horizontal pipelines. However, due to the complexity of the flow structure resulting from liquid-sand interactions, the mechanisms responsible for bed-load transport flow for hydraulic conveying of sand particles have not been extensively studied in inclined pipelines. This paper presents an experimental investigation of hydraulic conveying of sand particles resulting from a stationary flat bed in both horizontal and +3.6 degree upward inclined pipelines. The characteristics of sand transportation by saltation from an initial sand bed are experimentally visualized using a transparent Plexiglas pipeline and high-speed digital photography. The dune formation process is assessed as a function of pipeline orientation. Based on the visualized dune morphology, pipeline inclination is found to have a significant influence on hydraulic conveying of sand dune dynamics (i.e., dune velocity), as well as sand dune geometry (i.e., dune pitch and characteristic dune angles).

Optimization of Bridge Windbreak on High-Speed Railway through Strong Wind Area

2012 ◽  
Vol 452-453 ◽  
pp. 1518-1521 ◽  
Author(s):  
Ling Ling Zhou ◽  
Xi Feng Liang ◽  
Ming Zhi Yang ◽  
Sha Huang
Keyword(s):  
Protective Effect ◽  
Wind Velocity ◽  
High Speed ◽  
Wind Load ◽  
Aerodynamic Load ◽  
Strong Wind ◽  
High Speed Railway ◽  
Overturning Moment ◽  
Catenary System ◽  
Self Gravity

Based on 3-d, uncompressible onflow model with steady N-S equation and the k-epsilon double equation, aerodymic characteristics of EMU and windbreaks on bridge under cross wind were studied numerically, the results show: (1) compared to no windbreak, EMU overturning moment was decreased 50% by setting general windbreak , 75% by setting ventilated windbreak; ventilated windbreak’s protective effect on train and pantograph-catenary system is better especially when H≥2.5m ; (2) aerodynamic load on ventilated windbreak is far lower than general windbreak; (3)the higher cross-wind velocity is, the more aerodynamic load decreased when setting ventilated windbreak. Besides, ventilated windbreak’s leak form could significantly reduce bridge’s self gravity and wind load, improve wind break ability and EMU operation safety.

Optimization of Bridge Windbreak on High-Speed Railway through Strong Wind Area

2012 ◽  
Vol 452-453 ◽  
pp. 1518-1521
Author(s):  
Ling Ling Zhou ◽  
Xi Feng Liang ◽  
Ming Zhi Yang ◽  
Sha Huang
Keyword(s):  
High Speed ◽  
Strong Wind ◽  
High Speed Railway

Numerical Simulation of Behavior of Sand Particles during High-Speed Penetration with Particle Method

2016 ◽  
Vol 715 ◽  
pp. 198-202
Author(s):  
Ryota Shimono ◽  
Keiko Watanabe
Keyword(s):  
Numerical Simulation ◽  
High Speed ◽  
Free Particle ◽  
Particle Method ◽  
Particle Methods ◽  
Sand Particle ◽  
Mesh Free ◽  
Research Themes ◽  
Macro Scale ◽  
Sand Particles

The phenomena that occur during high-speed penetration of a projectile into sand particles are interesting subjects in engineering. The macro-scale research themes are the behavior of the ejected sand particles and the progress of the high-speed projectile, while the micro-scale research themes are the deformation and fragmentation of a single sand particle. Studies of these unique phenomena were conducted using both experiments and numerical simulation. Although accurate simulation of the behavior of sand particles during high-speed penetration is difficult because sand particles have characteristics of both fluids and solids, the reproducibility of the actual phenomena has improved in recent years with the development of particle methods. In our research, we conducted simulations of the phenomena using Smoothed Particle Hydrodynamics (SPH), which is a mesh-free, particle-based method. The results showed the possibility of accurate reproduction during high-speed projectile penetration into sand particles at the macro-scale.

Experimental study on the high-speed impact of a sand particle on Ti–6Al–4V

2019 ◽  
Vol 234 (4) ◽  
pp. 632-646
Author(s):  
Cheng Yan ◽  
Wei Chen ◽  
Zhenhua Zhao
Keyword(s):  
High Speed ◽  
Impact Damage ◽  
Damage Mechanism ◽  
Impact Angle ◽  
Sand Particle ◽  
Compressor Blades ◽  
Supersonic Airflow ◽  
High Speed Impact ◽  
Sand Particles ◽  
The Impact

When sand is ingested by a helicopter engine, it collides with the compressor blades at a high relative speed, causing severe erosion damage. A test was conducted on the high-speed impact of sand particles on the target of Ti–6Al–4 V alloy to enhance the understanding of high-speed impact damage mechanism. The test apparatus was used to create supersonic airflow, which was produced by normal temperature air flowing through a special Laval nozzle. The supersonic airflow produced the drag force to increase the velocity of sand particles up to about 400 m/s. The experiment demonstrated that fractured sand particle caused less damage than nonfractured particle under similar impact conditions. The nonfractured particle directly cut the target more easily than the fractured at a relatively low impact velocity. When the impact speed exceeded 300 m/s, the crater depth increased exponentially with the increase of velocity. Impact angle determined the mode of material failure.

Aerodynamic Effects of Viaduct-Cutting Connection Section on High-Speed Railway by Wind Tunnel Tests

2019 ◽  
Vol 32 (5) ◽  
pp. 05019002 ◽  
Author(s):  
Yongle Li ◽  
Jingyu Zhang ◽  
Mingjin Zhang ◽  
Zewen Wang ◽  
Junjie Guo
Keyword(s):  
Wind Tunnel ◽  
High Speed ◽  
High Speed Railway ◽  
Wind Tunnel Tests
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