Analysis on Additional Pressure of Tube Sidewall of Immersed Tube Tunnel in Sinking Process of Tube Segment

2013 ◽  
Vol 387 ◽  
pp. 180-184
Author(s):  
Ya Dong Li ◽  
Hai Hong Mo ◽  
Jun Shen Chen
Keyword(s):  
Fluid Dynamics ◽  
Numerical Simulation ◽  
Simulation Analysis ◽  
Lateral Wall ◽  
Special Position ◽  
Additional Pressure ◽  
Whole Process ◽  
Pressure Changes ◽  
Dynamics Method ◽  
Tube Segment

The numerical simulation analysis on the whole process of the tube immersing is researched, which use computational fluid dynamics method, is based on RNG k~ε turbulence model. The analysis shows that: additional pressure of tube lateral wall depends on the changed flow field cause by tube immersing; through the analysis, it have explored the special position of additional pressure changes in the process of immersing; it also shows some problems should be paid attention, through analysis the stress of special position.

scholarly journals Numerical Simulation Analysis of NPR Anchorage Monitoring of Bedding Rock Landslide in Open-Pit Mine

2020 ◽  
Vol 2020 ◽  
pp. 1-17
Author(s):  
Kai Zhang ◽  
Xiaojie Yang ◽  
Xuebin Cui ◽  
Yong Wang ◽  
Zhigang Tao
Keyword(s):  
Numerical Simulation ◽  
Early Warning ◽  
Simulation Analysis ◽  
Failure Process ◽  
Open Pit Mine ◽  
Open Pit ◽  
Stress Monitoring ◽  
Anchor Cable ◽  
Whole Process ◽  
Rock Landslide

Nanfen open-pit iron mine is the largest single open-pit mine in Asia. Because of the lag of the extension project, the section has slowly spread in the shape of “V,” and disasters such as landslides occur frequently. In this study, first, the NPR anchor cable monitoring, which shows supernormal mechanical characteristics and can realize the monitoring and early warning target for the whole landslide process and early warning curve of bedding rock “2016-1101 landslide” in the lower wall of Nanfen open-pit mine, was analyzed, revealing the failure process of the bedding rock landslide and the force evolution characteristics of the NPR anchor cable. Then, based on the Fish language in FLAC3D and 3DEC software, the mechanical model of the NPR anchor cable was constructed, and numerical simulation was performed on the whole process of “16-1101 landslide” induced by accumulation of old landslide body. The results of this study indicate that the stress monitoring curves and failure characteristics of the NPR anchor cables in the whole process of landslide by the two numerical simulation methods are basically consistent with the field measurement results, providing a theoretical and practical basis for the mechanistic analysis and numerical simulation of other similar slopes.

Numerical Simulation of Flash Floods Routing Based on Improved Leap-Frog Method

2013 ◽  
Vol 347-350 ◽  
pp. 2173-2177
Author(s):  
Jia Hua Zhang ◽  
Chi Zhang
Keyword(s):  
Numerical Simulation ◽  
Moving Boundary ◽  
Simulation Analysis ◽  
Flash Flood ◽  
Mass Conservation ◽  
Correction Method ◽  
Gansu Province ◽  
Simulation Accuracy ◽  
Whole Process ◽  
Steep Terrain

in the 2-d numerical simulation of flash flood disaster, due to flood often occurred in the steep terrain and water flow rapidly changed, lead to that the calculated value is unstable and even the calculation diverge in the simulation. This paper presents a grid outflow correction method, which is based on the leap-frog finite difference format, through modifying the outflow rate of the grid circularly, to ensure the mass conservation in the whole process of computing. In the local dam bursting model, the simulated result comparison of the grid outflow correction method and the algorithm of implicit alternating direction on the mass conservation shows that, the new method can ensure the simulation accuracy and the numerical stability under the condition of steep terrain and moving boundary. According to the proposed method, the simulation analysis in the process of extreme flash flood disasters which happened in 2010 Zhouqu county in Gansu province was carried out. The comparison of simulation results and remote sensing estimation results shows that the deviation of the flood evolution time, speed and impact height are within 5%, and the consistency of evolution path is good, which verifies the validity of the algorithm.

Optimal Design of a New Type of Savonius Rotor Using Simulation Analysis

2012 ◽  
Vol 499 ◽  
pp. 120-125 ◽  
Author(s):  
Zhi Peng Tang ◽  
Ying Xue Yao ◽  
Liang Zhou ◽  
Q. Yao
Keyword(s):  
Fluid Dynamics ◽  
Numerical Simulation ◽  
Computational Fluid Dynamics ◽  
Optimal Design ◽  
Simulation Analysis ◽  
Structural Parameters ◽  
Sliding Mesh ◽  
Savonius Rotor ◽  
Mesh Method ◽  
New Type

In order to enhance the efficiency of the Savonius rotor, this paper designs a new type of Savonius rotor with a rectifier. By using Computational Fluid Dynamics software to simulate and optimize the various parameters which affect the efficiency of the rotor. The sliding mesh method is applied here. The Cp-λ curves of wind turbine with different structural parameters are obtained after numerical simulation of flow field. On this basis, this paper gets the optimal structural parameters. And the results indicated that this new type of Savonius rotor has great improvement of efficiency compared with the traditional Savonius-type rotor.

Analysis to Evolution of Numerical Simulation to the Whole Process of Destroy for Main Arch of Stone Arch Bridge

2013 ◽  
Vol 361-363 ◽  
pp. 1150-1154
Author(s):  
Liang Yan Mao ◽  
Chang Qing Wang ◽  
Li Yong Zhang
Keyword(s):  
Numerical Simulation ◽  
Test Object ◽  
Simulation Analysis ◽  
Plastic Hinge ◽  
Experimental Results ◽  
Service Work ◽  
Work Condition ◽  
Whole Process ◽  
Damage Simulation ◽  
Main Arch

6m arch board used as test object, this paper introduces the arch in different level of load board cracks, development and production of plastic hinge until the whole process for all the damage simulation numerical simulation analysis then compared with experimental results and analysis of increased with load crack distribution, which can be used to understand the similar in service work condition of the stone bridge.

scholarly journals Optimal Design of Computational Fluid Dynamics: Numerical Calculation and Simulation Analysis of Windage Power Losses in the Aviation

Processes ◽  
2021 ◽  
Vol 9 (11) ◽  
pp. 1999
Author(s):  
Yuzhong Zhang ◽  
Linlin Li ◽  
Ziqiang Zhao
Keyword(s):  
Fluid Dynamics ◽  
Numerical Simulation ◽  
Computational Fluid Dynamics ◽  
Turbulence Model ◽  
Power Loss ◽  
Simulation Analysis ◽  
Gear Tooth ◽  
Tooth Surface ◽  
Phase Flow ◽  
Gear Pair

Based on the theory of computational fluid dynamics (CFD), with the help of the Fluent software and the powerful parallel computing capability of the super cloud computer, the single-phase flow transient simulation calculation of the windage power loss of the engagement spiral bevel gear pair (SBGP) was performed. The two-equation SST k-ω turbulence model based on the assumption of eddy viscosity was adopted, which was improved from the standard k-ε model combined with the Wilcox k-ω model. The SST k-ω turbulence model inherited the respective advantages of the Wilcox k-ω model in the near-wall region and the k-ε model in the free shear layer and could more accurately describe the resistance and separation effect of the gear tooth surface on the airflow. The simulation analyzed the airflow characteristics around SBGP and the mechanism of the windshield to reduce the windage loss of the gear. It also studied the influence of the windshield clearance and opening size on the windage power loss. Then the orthogonal experimental analysis method was adopted to perform numerical simulation analysis. The windage torque was studied under different clearance values between the windshield and the gear tooth surface, as well as the large end and the small end. The variance analysis was performed on the numerical simulation data. The results showed that when the windshield clearance value was 1 mm and the engagement opening was 30°, the windage torque was the smallest, and the effect of reducing the windage power loss was the best. According to the changes in the pressure, velocity, and turbulent kinetic energy cloud diagram of the flow field in the reducer during multi-group simulation tests, the local optimal windshield configuration was obtained, which provided a method for further research on the multi-objective optimization of the windshield and the windage loss of the gear pair under the oil–gas two-phase flow and also provided a reference for the practical engineering application of the windshield.

scholarly journals Numerical simulation on the emission of NOx from the combustion of natural gas in the sidewall burner

2021 ◽  
pp. 61-61
Author(s):  
Mingyu Wang ◽  
Jing Zhao ◽  
Feihong Guo ◽  
Lingli Zhu ◽  
Dekui Shen ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Numerical Simulation ◽  
Natural Gas ◽  
Environmental Problem ◽  
Nox Emission ◽  
Mixing Rate ◽  
Fuel Gas ◽  
Industrial Facilities ◽  
Low Nox Emission ◽  
Dynamics Method

The NOx produced from industrial facilities is a serious environmental problem in China. In this work, the NOx emission from the combustion of natural gas in the sidewall burner was investigated by using computational fluid dynamics method. To achieve the low-NOx emission, the sidewall burner structure was optimized involving the width of the primary premixed gas outlet, the secondary fuel gas nozzles number and angular spacing. The mixing rate of fuel gas and air could be improved by increasing the width of primary premixed gas outlet, and the lowest NOx emission of 32.8 ppm was achieved at the width of 8 mm. The NOx emission was remarkably reduced with the increasing of nozzles number, where 28.33 ppm of NOx emission and 357.35 ppm of CO were obtained at 4 nozzles. The combustion performance and NOx emission was improved as well as NOx emission was reduced at the angular spacing of 55?, compared to that of 30?, 35?, 40?, 45?, 50? and 60?.

Numerical and Experimental Investigation on Forced-Air Cooling of Commercial Packaged Strawberries

2019 ◽  
Vol 15 (7) ◽  
Author(s):  
Da Wang ◽  
Yanhua Lai ◽  
Hongxia Zhao ◽  
Binguang Jia ◽  
Qiang Wang ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Numerical Simulation ◽  
Experimental Investigation ◽  
Simulation Model ◽  
Cooling Time ◽  
Air Cooling ◽  
Cooling Process ◽  
Uniformity Coefficient ◽  
Forced Air ◽  
Dynamics Method

AbstractThe numerical simulation model of forced-air cooling of strawberries in a clamshell and a box was established by using computational fluid dynamics method. The cooling process of the simulation and the experiment results agreed well in different conditions, indicating that the simulation model was validated. The results showed that the 7/8 cooling time was 180 min, 135 min, 108 min and 100 min and the cooling uniformity coefficients were 0.31, 0.22, 0.24, 0.26 when the diameters of B-vent(the vent on the box) were 30 mm, 40 mm, 50 mm, 60 mm, respectively. The 7/8 cooling time decreased and the cooling uniformity coefficient improved, when the shape of C-vent (the vent on the clamshell) changed from round to rectangular. The 7/8 cooling time also deceased and the cooling uniformity coefficient increased, when the area of C-vent with both round and rectangular shapes increased. These results indicate that both B-vent and C-vent had significant effect on reducing the cooling time and the improving cooling uniformity for strawberries, It is suggested that the optimized vent ratio of B-vent (the diameter is 40 mm) and C-vent (15 mm round or 20 mm × 15 mm rectangular) for the current commercial packaged strawberries were 9.4 % and 8.5 %, respectively.

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