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ZhengZhou municipal office for the construction and management of rail transit, China, 450017) azhongwei@zzu.edu.cn, byjpkl@mail.ustc.edu.cn Key Words: Urban tunnel ; Fire; Natural ventilation; Shaft height Abstract: The characteristics of smoke flow in natural ventilation shaft are studied in this paper, Using the computational fluid dynamics software FDS5.0 to build a 3D model of an urban tunnel with a smoking shaft, Large Eddy Simulation model was used to obtain the structure of flow field and the mass flow rate of natural ventilation at different shaft height, The results show that when the shaft height is low, the driving force of exhaust is weak and the exhaust capacity reduces rapidly, the flow state in shaft is controlled by horizontal inertia force; when the shaft height increase to a critical height, the exhaust effect enhance significantly, the flow state in shaft will change to stack effect control.
The flow field of fire smoke with the function of smoking shaft is analyzed in this paper, the effect of natural ventilation with the change of shaft height is studied by Large Eddy Simulation model.
Numerical simulation method and Fire scenario design This paper selects the numerical simulation tool FDS5.0 (Fire Dynamics Simulator) developed by NIST, which is a Computational Fluid Dynamics (CFD) simulation model of fire-driven flow[4].
Stack effect control horizontal inertia force control Fig.4 The mass flow rate of ventilation Conclusion This paper simulated an urban tunnel with a smoking shaft by Large Eddy Simulation model. obtaining the flow field, temperature distribution in shaft and the mass flow rate of ventilation at different shaft height.

FloVENT is powerful computational fluid dynamics (CFD) software that predicts 3D airflow, heat transfer, contamination distribution and comfort indices in and around buildings of all types and sizes.
Through 3D heat transfer and whole building energy simulations the impact of introducing a balcony thermal break on the overall heat transmittance, floor surface temperature distribution, and the total heating energy consumption is evaluated for a typical balcony detail.
[2] Kosny, J., A New Whole Wall R-value Calculator, An Integral Part of the Interactive Internet Based Building Envelope Materials Database for Whole-Building Energy Simulation Programs, 2004
Clarke, Energy Simulation in Building Design, Adam Hilger Ltd, UK, 1985
Frank, Experimental and numerical thermal analysis of a balcony board withintegrated glass fibre reinforced polymer GFRP elements, Energy and Buildings 39 (2007) 76–81 [11] FLOVENT, CFD (computational fluid Dynamics), 3D Airflow Modeling Software, Mentor graphics corporation, USA, Version 9.1, 2011

Numerical Simulation of the cooling effect by air conditioner and spraying in high-temperature working face LIU Guan-nan a, GAO Feng b, JI Ming c, LIU Xing-guang d College of Science, China University of Mining &Technology, Xuzhou, 221000,China a guannanliu@126.coml, b ssnn521@126.com, c iflove0922@126.com, d youxiang_liu@126.com Keywords: stochastic model; working face; temperature field; SIMPLE algorithm.
A multicomponent turbulent model of the airflow in working face was modeled.And the simulation result is compared with the measured temperature.The temperature of the airflow along the transportation channel of working face goes up,and the gradient of the temperature curve is flat.Then the low-temperature droplets are simulated by stochastic separated flow model.The interaction between grains and fluid are simulated by adding source terms in conservation equations.The temperature curves of the airflow under different cooling schemes are investigated.If the air conditioner is in front of the nozzles,the temperature of the air near the inlet is low and uniform,and the cooling effect of the outlet is obvious.
The simulation result and the measured temperature in the transportation channel From Fig.1 shows that the simulation result well fits the measured data .The temperature of the airflow goes up along the channel,and the temperature difference between the inlet and the outlet is about 1℃.The model could be used for analyzing the distribution of the temperature in mine.
[5] Zhou Lixing.Simulation of turbulent two-phase flow and combustion.Beijing:Tsinghua university press,(1991) [6] Patankar S.V.Sparrow E.M.and Inanovic M.Heat Mass Transfer Vol.24.(1978) [7] Berlemont A,Grancher M S,Gouesbet G.
[9] Wang Fujun.Analysis of computational fluid dynamics-theory and application of CFD softwares..Beijing:Tsinghua university press,(1991)

The simulation of two different cases shows the propagation of a single acoustic mode in annular duct pictorially.
During the simulation, the most advanced perfectly matched layer[9]is used to prescribe the mode and to serve as non-reflection boundary conditions.
Mincu, Numerical simulation of the fan noise radiated through a semi-buried air inlet.
Li, X.D., et al., Numerical simulation of duct inlet noise.
CFD Journal, 2000. 9(1): 485-491

The simulation results can guide the design and optimization of mini-hydrocyclones and determine the optimum inlet aspect ratio.
Turbulence model The turbulence model is the key in CFD simulation.
Accordingly, the simulation results show significant limitations.
Simulation 2.1 Geometry and meshing.
Analysis of the Simulations 3.1 Tangential velocity.

The research method in this paper is numerical simulation; numerical simulation involves Direct Numerical Simulation[1,2,3], large eddy simulation[4] and RANS.
Although both the wind tunnel test and the CFD simulation are necessary methods when solving vehicle aerodynamic characteristics problems, which are not isolated and should be mutual supplemented and cooperated.
Numerical simulation has irreplaceable merits and has got a position in vehicle aerodynamic characteristics research; such as, numerical simulation design period is short; numerical simulation can save enormous labor, financial and material resources.
The model is simplified in simulation, omitting the door handles, windshield wipers and rearview mirror, omitting the wheels and filling the wheel pits.
Rodi, "Direct numerical simulation, large eddy simulation and unsteady Reynolds-averaged Navier-Stokes simulations of periodic unsteady flow in a low-pressure turbine cascade: A comparison", Journal of Power and Energy, vol217, 2003, p. 403-412 [3] V.

Fig. 1 Human mouth-throat model 1.2 Governing equations 1.2. 1 Governing equations of the gas phase The large eddy simulation used in the paper is a transition between direct numerical simulations and theoretical model simulations.
The results show that the numerical simulation data are in reasonable agreement with experimental measurements, which verifies that the large eddy simulation methods are accurate and reasonable.
The following conclusion can be drawn: 1) Large eddy simulation data are in reasonable agreement with Particle Image Velocimetry (PIV)experimental measurements, which verifies that the simulation methods are accurate and reasonable.
CFD simulation of aerosol deposition in an anatomically based human large-medium airway model.
Large eddy simulation of inhaled particle deposition within the human upper respiratory tract.

Simulation Methodology Geometry.
It has been simplified by removing all small and medium sized parts and filling up the cavities because the real model is too complex for the current CFD study.
Simulation Setup.
St Fig. 5 Noise spectra comparison between simulation and experiment at R2 Simulation Results.
The simulation data is coincident with the experiment data.

Numerical Simulation of Ventilation Air Methane Counter-current Oxidation Reaction WANG Ying-Hua1, a, JIA Bao-Shan1, b, SHI Jun-Rui2, c, DENG Yang-Bo3, d, TIAN Yu1, e 1School of Safety Science and Engineering, Liaoning Technical University, Liaoning Fuxin 123000, China 2ShenYang Institutes of Engineering, Shenyang Circulating Fluidized-bed Combustion Technology Key Laboratories Liaoning Shenyang 110136, China 3Mechanical and Electronic and Materials Engineering Institute, Dalian Maritime University, Liaoning Dalian 116026, China awyh850903@163.com, bjbs1972@126.com, cshijunrui2002@163.com, ddengyb1970@163.com, ety880503@126.com Keywords: ventilation air methane; countercurrent oxidation; numerical simulation; equivalence ratio; half cycle Abstract: In this paper, based on the theoretical analysis and reasonable simplification, one-dimensional mathematical model is presented for the counter-current oxidation of ventilation air methane.
The process of counter-current oxidation reaction is simulated by applying the computational fluid dynamics (CFD) software (Fluent), and the effect of the dominating working parameters (such as flow velocity and equivalence ratio and half cycle) are discussed on the temperature and rate of reaction within the counter-current oxidation reaction.
are simplified as follows: Inlet: , Outlet: Outer wall temperature: Initial temperature: 2 Simulated results and analysis Based on the simulation research of the countercurrent oxidation device, the burning mechanism and characteristics are understood, and the effects of different working parameters are obtained on the combustion characteristics.
Porous medium reciprocating flow burning a numerical simulation.
Numerical Simulation on Reciprocating Super adiabatic Combustion Of Premixed Gases in Porous Media Journal Combustion science and technology, 2005 11(3),pp.230-235

Meanwhile, in order to verify reliability of the thermal gas mass flow meter in the system, we adopted CFD method to simulate the EGR cooler by using empirical parameters, and collected several related sensor parameters of the EGR cooler in the condition that the inlet temperature was constantly at 368K while the coolant had 4 kinds of degrees.
Temperature and pressure cloud chart of the EGR cooler flow field Table2 is the experimental results of EGR cooler; table3 is the simulation results of EGR cooler.
Simulation results of the EGR cooler (K) (L/min) (K) (bar) (kg/h) (bar) (kPa) (kPa) (K) 368 20 836 2.1 91 1.6 20 10 472 368 25 836 2.1 90 1.6 20 14 468 368 30 836 2.1 90 1.6 20 19 463 368 35 836 2.1 90 1.6 20 28 461 According to Table 2 and Table3, the critical data EGR gas outlet temperature, the overall heat transfer coefficient and coolant flow curve are plotted into figure 5.
Compared to simulation values, the gas outlet temperature of the experimental value is about 1.17% lower on average; and the heat transfer coefficient is 3.1% larger on average.
Meanwhile, in order to verify reliability of the thermal gas mass flow meter in the system, we adopted CFD method to simulate the EGR cooler using empirical parameters, and collected several related sensor parameters of the EGR cooler in the condition that the inlet temperature is constantly 368K while the coolant had 4 kinds of degrees.