Three-Dimensional Numerical Analysis on Heading Construction of Metro Station by Drift-PBA Method

2011 ◽  
Vol 243-249 ◽  
pp. 3423-3426 ◽  
Author(s):  
Yang Yuan ◽  
Wei Ning Liu ◽  
De Yun Ding ◽  
Xin Cai Gao ◽  
Meng Ma ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Numerical Analysis ◽  
Environmental Impacts ◽  
Three Dimensional ◽  
Metro Station ◽  
Construction Sequence ◽  
Calculation Results

Drift-PBA method has been widely used in the construction of metro station. Yet the discussion about the excavation sequence of headings was still a controversy. In this paper, three-dimensional numerical simulation of a metro station construction by drift-PBA was conducted by MIDAS/GTS. The heading construction sequence was studied in the environmental impacts due to the construction, and some suggestions were provided for the site. The calculation results indicated that excavating the upper headings previously could effectively control the shapes of settlement troughs and the deformations of pipelines, and diminish the disturbance to the stratum.

scholarly journals Study of the Effect of Centrifugal Force on Rotor Blade Icing Process

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Zhengzhi Wang ◽  
Chunling Zhu
Keyword(s):  
Numerical Simulation ◽  
Centrifugal Force ◽  
Rotor Blade ◽  
Flow Direction ◽  
Three Dimensional ◽  
Simulation Method ◽  
Two Phase ◽  
Numerical Simulation Method ◽  
Calculation Results ◽  
Flow Field Characteristics

In view of the rotor icing problems, the influence of centrifugal force on rotor blade icing is investigated. A numerical simulation method of three-dimensional rotor blade icing is presented. Body-fitted grids around the rotor blade are generated using overlapping grid technology and rotor flow field characteristics are obtained by solving N-S equations. According to Eulerian two-phase flow, the droplet trajectories are calculated and droplet impingement characteristics are obtained. The mass and energy conservation equations of ice accretion model are established and a new calculation method of runback water mass based on shear stress and centrifugal force is proposed to simulate water flow and ice shape. The calculation results are compared with available experimental results in order to verify the correctness of the numerical simulation method. The influence of centrifugal force on rotor icing is calculated. The results show that the flow direction and distribution of liquid water on rotor surfaces change under the action of centrifugal force, which lead to the increasing of icing at the stagnation point and the decreasing of icing on both frozen limitations.

Numerical Simulation of Flow Process of Ammonium Persulfate Crystallizer

2014 ◽  
Vol 997 ◽  
pp. 396-400
Author(s):  
Yu Guang Fan ◽  
Ting Wei
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Three Dimensional ◽  
Ammonium Persulfate ◽  
Flow Process ◽  
Calculation Results ◽  
Crystallization Effect ◽  
Computational Fluid Dynamics Cfd ◽  
The Impact ◽  
Selection Of

The method of computational fluid dynamics (CFD) is used to three-dimensional numerical simulation for the fluid flow process of ammonium persulfate crystallizer. By using standard model, this paper respectively simulated the flow field within the crystallizer in the impeller installation height of 1.2 m while stirring speed is of 60 r/min, 100 r/min and 200 r/min; and simulated the impact of the flow field inside the crystallizer when the stirring speed of 100 r/min and impeller installation height respectively is of 0.7 m, 1.2 m and 1.7 m. That calculation results show that: the velocity gradient is mainly concentrated in the area of internal draft tube and paddle around. With the increase of impeller speed, the flow velocity of the fluid within the crystallizer corresponding increases; and the energy also gradually decreases from mixing impeller to the settlement zone with the loss of the installation height, and the kinetic energy in the bottom of the crystallizer is reduced. Considering the energy and crystallization effect, selection of mixing speed of 100 r/min or so and installation height of about 1.2 m is more appropriate.

Numerical Analysis of the Influence of Export Structure on Jet Fan Aerodynamics Performances

2015 ◽  
Vol 713-715 ◽  
pp. 3-6
Author(s):  
Yu Shan Wang ◽  
Di Lin Pan
Keyword(s):  
Numerical Simulation ◽  
Numerical Analysis ◽  
Internal Flow ◽  
Simulation Research ◽  
Export Structure ◽  
Aerodynamic Performances ◽  
Calculation Results ◽  
Jet Fan

The internal flow of jet fan has been simulated using FLUENT software.By changing the length of exit duct and the angle of the exit cowl,a series of numerical simulation research has been done.The calculation results show that the length of exit duct and structure of exit cowl has obvious influence on jet fan aerodynamics performances and reasonable export structure can effectively improve jet fan aerodynamic performances.

Three-Dimensional Sediment Numerical Simulation of Wenzhou Oufei Tidal Flat Sea Area

2012 ◽  
Vol 535-537 ◽  
pp. 1775-1779
Author(s):  
Jia Rui Li ◽  
Lei Mo ◽  
Wen Hu Zhang
Keyword(s):  
Numerical Simulation ◽  
Mathematical Model ◽  
Tidal Flat ◽  
Concentration Distribution ◽  
Three Dimensional ◽  
Sediment Concentration ◽  
Basic Law ◽  
Open Sea ◽  
Calculation Results ◽  
Sea Area

A flow and sediment mathematical model was built under three-dimensional hybrid coordinate to simulate Wenzhou Oufei tidal flat and its neighboring sea area, and the verification was down. The calculation results and the observed data are identical well. In estuary area, the sediment concentration is the highest, then outside the estuary. In Oufei tidal flat area, the sediment concentration is relatively high, and it decreases gradually towards the open sea. Through the simulation, the characteristics and the basic law of sediment concentration distribution was reproduced.

Strengthening of Masonry Walls with GFRP Straps – Testing and Application

2013 ◽  
Vol 688 ◽  
pp. 230-236
Author(s):  
Josip Galic ◽  
Tomislav Kisicek ◽  
Martina Galic
Keyword(s):  
Numerical Simulation ◽  
Numerical Analysis ◽  
Glass Fiber ◽  
Brittle Material ◽  
Three Dimensional ◽  
Masonry Structure ◽  
Masonry Walls ◽  
Microplane Model ◽  
Non Linear

This paper describes the results of testing of unstrengthened and strengthened masonry walls subjected to horizontal in-plane load. Three kinds of specimens were tested: unstrengthened walls, walls strengthened with horizontal and walls strengthened with diagonal glass fiber straps. For unstrengthened walls and those strengthened with horizontal straps, a numerical simulation was performed. Software called MASA was used for this analysis. This software uses three dimensional non-linear numerical analysis of structure, made of quasi-brittle material, which is described with a microplane model. The results of numerical analysis very well described the behavior of unstrengthened and strengthened walls. In this paper, the application of such kind of strengthening, on rehabilitation of the existing masonry structure, Villa Kallina, in Zagreb, Croatia, was presented.

Metro Station Deformation Caused by Deep Foundation Pit Construction

2014 ◽  
Vol 580-583 ◽  
pp. 1061-1064
Author(s):  
Chun Lei Xin ◽  
Bo Gao
Keyword(s):  
Numerical Simulation ◽  
Three Dimensional ◽  
Simulation Method ◽  
Main Body ◽  
Deep Foundation ◽  
Foundation Pit ◽  
Metro Station ◽  
Deep Foundation Pit ◽  
Construction Methods ◽  
Transfer Station

Many excavation and backfill methods can be used to construct a deep foundation pit, but foundation pit construction will undoubtedly affects security of existing metro station. This research based on a transfer station of Chengdu Metro, three-dimensional numerical simulation method was used to analyze the deformation of metro station by changing construction methods of foundation pit. The results show that: (1) Both excavation and backfill methods of foundation pit have a significant effect on connection segments of metro station. (2) The main body of metro station is largely unaffected by foundation pit construction but it has been in the process of subsidence. (3) The more the construction steps of foundation pit are, the more slowly the displacement of metro station changes. The above results certainly contribute to research and develop new types of construction methods for complicated metro station.

Hydrodynamic Performance of Leading-Edge Tubercle Three-Dimensional Airfoil

2012 ◽  
Vol 152-154 ◽  
pp. 1509-1515 ◽  
Author(s):  
Feng Feng ◽  
Xiang Ru Cheng ◽  
Xiang Yang Qi ◽  
Xin Chang
Keyword(s):  
Numerical Simulation ◽  
Research Method ◽  
Optimization Design ◽  
Lift Coefficient ◽  
Three Dimensional ◽  
Leading Edge ◽  
Hydrodynamic Performance ◽  
Normal Model ◽  
Edge Profile ◽  
Calculation Results

Based on RANS method, this paper studied leading-edge tubercle three-dimensional airfoil, which had effect on hydrodynamic performance of three-dimensional airfoil. Both section configurations of the two three-dimensional airfoil models were NACA0020 airfoil. The research method was numerical simulation. First, the leading-edge profile of the first airfoil model was normal. To get stalling angle of the first model, it analyzed hydrodynamic performance of the first model under different angle of attacks at Re=1.35*105. Then, the second model had a sinusoidal leading-edge profile. The second model chose the same Reynolds number. By comparison the numerical calculation results between the first and the second model, the stalling angle of second model delays 3°than the normal airfoil, and the lift coefficient of the second model increases 11.92% than the normal model. The results have laid the foundation for optimization design of leading-edge tubercle three-dimensional airfoil.

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