scholarly journals Study on temperature field of entrance section at high altitude tunnel considering water supply from snowmelt

2021 ◽  
Vol 25 (6 Part B) ◽  
pp. 4597-4604
Author(s):  
Guo-Dong Niu ◽  
Zhi-Qiang Liu ◽  
Ning Li ◽  
Hao-Xuan Zhou ◽  
Gang Yang
Keyword(s):  
Temperature Field ◽  
Water Supply ◽  
High Altitude ◽  
Great Influence ◽  
Side Wall ◽  
Model Tests ◽  
Freezing Injury ◽  
Entrance Section ◽  
Supply Condition ◽  
Tunnel Entrance

To explore the influence of snowmelt supply at the entrance section at high altitude tunnel on tunnel engineering, several indoor model tests were carried out by setting a water-supply system above the model device for simulating the actual snowmelt supply environment. The model tests were based on a project at high altitude tunnel in Qinghai. The varied characteristics of temperature field in typical cross-sections of tunnel entrances with and without water-supply condition under freeze-thaw cycles were analyzed accurately by the model. This study shows that the external water supply has a great influence on the tunnel entrance. When the surrounding rock freezes at the tunnel entrance, it first freezes from the arch, then develops to the side wall, and then spreads to the inverted arch to form a freezing circle. The faster the freezing development rate is, the greater the thickness of the freezing ring is under the water-supply condition. The development of temperature field under water-supply condition is obviously faster than that under normal condition. The distribution characteristics of freezing depth in both conditions are the arch is the largest, the side wall is the second, and the inverted arch is the smallest. This study can provide a reference for analyzing the process of freezing injury caused by high altitude snowmelt water supply into tunnel entrances in western Sichuan.

Thermoeconomic Analysis of a Solar MVC Desalination System

2018 ◽  
Author(s):  
Lei Gao ◽  
Yunho Hwang ◽  
Gyeong Sung Kim
Keyword(s):  
Water Supply ◽  
Fresh Water ◽  
Great Influence ◽  
Operating Conditions ◽  
Specific Power ◽  
World Population ◽  
Vapor Compression ◽  
Solar Pv ◽  
Pump System ◽  
Fresh Water Supply

Globally, about 10% of the world population does not have access to enough fresh water. In many hot-and-dry coastal regions and islands, the desalination of seawater might be the only practical option to have a fresh water supply. Therefore, low-cost desalination system is critical for freshwater demands. To address this issue, a desalination system consisting of solar photovoltaic (PV) and mechanical vapor compression subsystem is proposed in this study. The entire desalination system was modeled and designed to produce 10,000 m3 of fresh water per day at the coast of San Francisco, California. Key components such as water vapor compressor, solar PV panel, and three-stream heat recovery unit were designed, and their performances were analyzed. The effects of design variables and operating conditions on the system performance were investigated through a parametric study. Finally, an economic analysis was conducted and compared with current desalination technologies. The analysis results show that the specific power consumption of desalination system can reach 14.4 kWh/m3 when the evaporation temperature is 70°C. It is found that the evaporating temperature has a great influence on the heat pump system efficiency and evaporator design. The levelized cost of the proposed system is $0.76 per m3 of fresh water which is lower than current grid-powered vapor compression desalination system and other thermal desalination systems. The proposed solar PV driven desalination improves thermoeconomics of desalination system by applying low-lift operating condition to the vapor compression cycle so that it can contribute to solving the fresh water supply challenges.

Experimental Determination of Water Motions Inside a Moonpool

2017 ◽  
Author(s):  
Bastien Abeil
Keyword(s):  
Experimental Determination ◽  
Transfer Functions ◽  
Side Wall ◽  
Model Tests ◽  
Irregular Waves ◽  
Video Recordings ◽  
Non Linear ◽  
Relative Water ◽  
Water Elevation

Model tests of a drillship with a rectangular moonpool opening were conducted in regular and irregular waves from the bow and bow-quarter. Most tests were conducted at zero speed, the rest was performed with the model towed to a speed of 10 kn. From the video-recordings and transfer functions of the measured relative water elevation inside the moonpool, the typical piston and first sloshing modes are well captured, for wave frequencies that agree relatively well with relevant formulations. A few tests conducted at varying wave amplitudes show that the water elevation is non-linear by nature, while repeat tests conducted with the moonpool fitted with two layers of side wall flanges shows that these can reduce the water motions by nearly 40 %.

Temperature Effect Analysis of the Twin Towers Concrete Cable-Stayed Bridge for Construction Control

2013 ◽  
Vol 671-674 ◽  
pp. 1055-1063
Author(s):  
Gui Zhen Wang ◽  
Ying Min Li
Keyword(s):  
Temperature Field ◽  
Temperature Effect ◽  
Great Influence ◽  
Internal Force ◽  
Construction Control ◽  
Effect Analysis ◽  
Temperature Changes ◽  
Distribution Rule ◽  
Cable Force ◽  
Main Girder

It exists a great influence on deformation and internal force of large span bridge when temperature changes, the influence of the temperature must be considered and try to avoid in the process of construction control. Under monitoring to the construction process of Tieluoping super-large bridge on the scene, the influence law on internal force of Tieluoping Bridge is analyzed considering temperature effect, and the influence considering the sunshine temperature difference on cable tower deviation and stress is obtained, and the size of influence of main girder elevation, cable force and strain because of temperature field and distribution rule internal temperature field are clear. It provides powerful help for the smooth construction.

Variation of Drivers' Visual Features in Long-Tunnel Entrance Section on Expressway

2011 ◽  
Vol 3 (1) ◽  
pp. 27-37 ◽  
Author(s):  
Haoxue Liu ◽  
Guangming Ding ◽  
Weihua Zhao ◽  
Hui Wang ◽  
Kaizheng Liu ◽  
...  
Keyword(s):  
Visual Features ◽  
Entrance Section ◽  
Tunnel Entrance

Non-Pressure Heater Utilization on Low-Capacity Industrial Boiler

2014 ◽  
Vol 960-961 ◽  
pp. 394-398
Author(s):  
Guang Hua Li ◽  
Qun Feng Yang
Keyword(s):  
Low Temperature ◽  
Water Supply ◽  
Waste Heat ◽  
Gas Temperature ◽  
Recycling System ◽  
Intermittent Water Supply ◽  
Supply Condition ◽  
Boiler Efficiency ◽  
Industrial Boiler

A new non-pressure waste heat recycling system was designed and arranged on KHSS0.5-0.7-AⅡ industrial coal-fired boiler to decrease the exhausted gas temperature about 35°C, improve the boiler efficiency about 3.2%. Results showed that this system can avoid low-temperature sulfur corrosion and operate in normal and intermittent water supply condition safely and economically.

scholarly journals A Slate Tunnel Stability Analysis considering the Influence of Anisotropic Bedding Properties

2019 ◽  
Vol 2019 ◽  
pp. 1-17
Author(s):  
Jun Cai ◽  
Guangyin Du ◽  
Haiwang Ye ◽  
Tao Lei ◽  
Han Xia ◽  
...  
Keyword(s):  
Shear Strength ◽  
Shear Failure ◽  
Progressive Failure ◽  
Great Influence ◽  
Side Wall ◽  
Model Verification ◽  
Tunnel Face ◽  
Tunnel Stability ◽  
Bedding Planes ◽  
Dip Angle

Bedding planes are the fundamental causes of anisotropic deformation and mechanical behaviors in slate, which will have great influence on tunnel stability. In order to analyse tunnel stability surrounded by slate, well-foliated slate in eastern Guizhou was taken as the specimen in tests. Microscopic analysis and test results show that slate can be regarded as a special continuous material. During the test, shear strength parameters and progressive failure varied when the direction of the bedding plane was changed, and two sets of reasonable shear strength were achieved by fitting. Numerical model verification is conducted before applying, and results indicate that the model can represent the anisotropic failure properties. So the model considering anisotropic shear strength simultaneously is utilized to analyse the tunnel stability in slate. When it is medium dip angle, the tunnel is significantly unstable especially for face and side walls, and at 45° (dip angle), the plastic zone depth ahead of the tunnel face can be the largest, being 1.7 times the tunnel height. The maximum deviator stress (σ1 − σ3) is centralized on the middle of the side wall, and also, the stress (σ1 − σ3) is the highest at 45° (dip angle), which will lead to shear failure.

scholarly journals Design and implementation of LED lighting intelligent control system for expressway tunnel entrance based on Internet of things and fuzzy control

2020 ◽  
Vol 16 (5) ◽  
pp. 155014772092574
Author(s):  
Ying Lu ◽  
Jin Wang ◽  
Xiaojun Bai ◽  
Hehan Wang
Keyword(s):  
Control System ◽  
Internet Of Things ◽  
Fuzzy Control ◽  
Traffic Flow ◽  
Intelligent Control ◽  
Flow Speed ◽  
Led Lighting ◽  
Intelligent Control System ◽  
Entrance Section ◽  
Tunnel Entrance

Due to the special characteristics of highway tunnels and vehicles, the interior of the tunnel is required to provide appropriate lighting to ensure the safety of driving vehicles, especially at the entrance section of the tunnel. At present, most of the tunnel entrance lighting control system only considers one single factor, the brightness outside the tunnel. However, in practice, the required lighting brightness in the tunnel is also related to traffic flow, speed, and other factors. Comprehensively utilizing these factors to improve the control strategy is urgently needed. To deal with this problem, this article has designed a multi-source information acquisition system for tunnel lighting based on the Internet of things technology, which combined with fuzzy control theory in order to develop an intelligent control system for LED lighting at the entrance section of the tunnel. The designed system was implemented and long-term tested in a real highway tunnel. The experimental results have shown that the system designed in this article can automatically control the brightness of the lighting inside the tunnel according to the real-time measurements of the brightness outside the tunnel, traffic flow, speed, and so on. Furthermore, the utilizations of the system can minimize the human and power consumption of tunnel lighting while ensuring the safety of tunnel traffic.

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