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Introduction There are three commonly methods to study tunnel fire ventilation: model test, actual fire simulation by abandoned tunnel and numerical simulation by CFD (Computational Fluid Dynamics) [1], in order to get the distribution of temperature, pressure and velocity.
CFD numerical simulation technique is widely used in tunnel fire ventilation study currently, which has the advantages of reducing the workload of the ground experiments, shorting the development cycle, saving experimental costs and so on, and its accuracy can be compared with the model test results [3].
CFD technology can visually simulate tunnel air flow velocity, temperature, pressure and other physical quantities, and the simulation results play a reference role on the selection of tunnel fire ventilation solutions.
CFD simulation of fire smoke behavior with transverse ventilation-comparison with model tests. 10th Intenrarsonal symposium on the Aerodynamics &Ventilation of Vehicle Tunnels, 2000
CFD simulations of a tunnel fire-Part Ⅰ[J].

Comparison of Turbulence Models in the Simulation of Fluid Flow in Corrugated Channel Aimen Tanougast1,a*, Krisztián Hriczó1,b 1Institute of Mathematics, Faculty of Mechanical Engineering and Informatics, University of Miskolc, Miskolc-Egyetemvaros, Miskolc, H--3515, Hungary atanougast.aimen@uni-miskolc.hu, bkrisztian.hriczo@uni-miskolc.hu Keywords: Turbulence, corrugated channel, vortex generators, k-ε, k-ω, Reynolds Stress Model (RSM), CFD.
Vortex generators are known to enhance heat transfer by promoting flow separation and modifying the flow direction, making their effect critical in such simulations.
Turbulence models provide the necessary approximations for Reynold’s stress, enabling the accurate simulation of turbulent flows [1].
· Two-dimensional simulation (∂∂x3=0 and u3=0)
CFD Letters, 11(10), 69-80

Flow and Heat-transfer Simulation Based on CFD and Experimental Study during High-Pressure Gas Quenching Zhijian Wang 1,a and Xiaofeng Shang 1,b 1 School of Mechanical and Electrical Engineering, Shenyang Aerospace University, Shenyang Liaoning, China, 110136 awangzhijian1974@sina.com, bxfshang@vip.sohu.com Keywords: High-pressure gas quenching, CFD, Flow and heat transfer, Temperature field, Flow field.
The hot wire anemometer is used to measure the inlet velocities of nozzles, which provides the boundary conditions for computer simulation.
By the computer simulation, the gas flow fields, work temperature fields and work cooling curves are attained.
Computational Fluid Dynamics (CFD) has been an important method to study the complex gas flow and heat exchange during high pressure gas quenching.
Figure 3 shows the simulation result of the velocity vector in Y = 0 section.

Wind Speed/(m/s-1) Human Senses V＜5 Cozy 5＜V＜10 Uncomfortable,action affected 10＜V＜15 Quite uncomfortable,action to be seriously affected 15＜V＜20 Insupportableness V＞20 Dangerous The Meteorological Data and CFD Computational Fluid Dynamics Analysis The Meteorological Data.
The Analysis of CFD Computational Fluid Dynamics.
Numeral simulation of fluid flow is that solving fluid dynamics equations discretly,which are obeyed by air flow,and display the result visually with computer graphics techniques.The numerical simulation technique is called computational fluid dynamics（CFD：Computational Fluid Dynamics）technique.
Since 1974, people have carried out the CFD technology application into the simulation and research work of building environment.With the development of computer technology,CFD with its low pay,convenience is applied widely.
References [1] R.Yoshie,A.Mochida:Journal of Wind Engineering and Industrial Aerodynamics,Vol.95(2007), p.1551 [2] Yoshihide Tominaga:Journal of Wind Engineering and Industrial Aerodynamics,Vol.96(2008), p.1749 [3] Li Baofeng, Architectural Design Ecological Strategy, Beijing: Tsinghua University, 2004:31,in Chinese [4] Lee Kun, Yu Zhuang, Wuhan Regional Wind Environment Influence in the Simulation Analysis of the Temperature, Beijing: resources science, 2006, 28 ( 6) :51-59,in Chinese [5] C.W.Tsang,K.C.S.Kwok,P.A.Hitchcock:Bilding and Environment,Vol.49(2012),p.167 [6] Yoshie,R,“CFD analysis of flow field around a high-rise building”,in Summaries of Technical Papers of Annual Meeting,Environ,Engg, II, AIJ,(1999),in Japanese [7] Kataoka,H,“Large Eddy Simulation of building”,in Summaries of Technical Papers of Annual Meeting,Environ,Engg,II,AIJ,(2003),in Japanese [8] Information on http://www.abbs.com.cn/

Experimental Study on Flow Field Characteristic of Bag Filter Fu Hai-ming, Zhao You-jun School of Enviromental science and engineering, Donghua Universiy, China No.2999, Renming Road, Songjiang, Shanghai,201620 China fhm@dhu.edu.cn Keywords: Bag Filter; Unevenness Distribution; CFD Numerical Simulation; Flow Field; Filtration Velocity.
In order to select best filtration velocity of bag filters and to improve gas flow distribution, to increase collection efficiency and to reduce operation resistance, gas flow distribution was tested by using hot-wire anemometer, CFD simulation was made and basic accordant result was obtained by comparing simulation result with experimental result.
[3] Dang xiaoqing; yuan shengli; yao qun et al; Study on gas flow distribution in straight inlet baghouse by using cfd method[J].
[4]Gao Hui; Guo Liejin.Numerical Simulation of Gas-Solid Two-Phase Flow in a Filter Dust Collector with a Low Entry[J].
Numerical Simulation and Analysis of the Gas-Solid Two Phase Flow in a Cartridge Filter[J].

The investigation of these flow field characteristics made use of the computational fluid dynamics (CFD) to simulate the air flow in the classifier.
During the last several years, Computational Fluid Dynamics (CFD) has garnered significance for its investigation of fluid flow[6].
In fact, the commercially packaged CFD software, Fluent, is one of the most efficient means of studying the fluid dynamics of many physical systems, having been widely used in engineering applications including simulation of flow fields in classifiers.
The use of CFD thus alleviates the problems of mass in material experiments and improves efficiency.
Investigation and simulation of a cross-flow air classifier.

The simulation showed a complex 3D flow pattern around the buildings.
This can be investigated by either physical models using a wind tunnel or numerical models using computational fluid dynamics (CFD) methods.
In addition, CFD simulations can provide detailed information of the wind flow field around the buildings under various conditions [6].
The CFD simulations can help to better plan urban areas by improving the wind environment around buildings via natural air ventilation.
This was confirmed by comparing the current simulations with the simulations of a prior study with buildings of the same height.

Standard curved pipes and guide plates which are widely used in practical application are simulated using computational fluid dynamics(CFD) in this paper.
Referring to the standard flue pipe upstream electrostatic precipitator used in a coal-fired power plant, flue gas pressure and velocity distribution in flue pipes bends using computational fluid dynamics(CFD) are investigated in this paper.
Simulation CFD implementation.
Table 2 Pressure loss simulation results Models Without inner supports With inner supports without guide plate with guide plate without guide plate with guide plate Pressure loss[Pa] 25.27 30.06 34.03 37.56 Table 3 Outlet velocity deviation simulation results Models Without inner supports With inner supports without guide plate with guide plate without guide plate with guide plate Outlet velocity deviation 0.39 0.24 0.51 0.43 Pressure distribution analysis.
According to current simulation results, the pressure loss of the flue pipe bends with guide plates is more than those without guide plates.

This paper summarizes the two methods which are experimental research and numerical simulation to thermal environment of the tunnel.
In addition, the solving accuracy of numerical simulation is closely related to the operator, so it has great subjectivity.
The three-dimensional model established on the CFD software is shown in Figure 1.The whole computational domain is 15*500*20m which consist of soil horizon and concrete layer.
Through CFD software, the radial temperature distribution of surrounding rock and the axial temperature distribution of air at winter and summer conditions are obtained.
Research on Simulation and Evaluation System of Energy Conservation for Tunnel Ventilation System[J].

CFD methods of turbulence are Direct Numerical Simulation (DNS), Large Eddy Simulation (LES) and Reynolds time average equation method.
The later two are Indirect Numerical Simulation.
The method will become a trend in CFD modeling for stirred reactor with the increase of computer performance.
Parallel computing CFD computation needs high speed and large capacity CPU.
CFD study of mixing process in stirred tank [J].