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A Numerical study of the Fire-extinguishing Performance of Ultrafine Water Mist in Small Scale Tunnel Space Tianshui Liang1,2,3, Jingjing Yu1, Guanpeng Lu1, Xiang Li1, Wei Zhong1,a and Siuming Lo3 1School of Chemical Engineering and Energy, Zhengzhou University, Zhengzhou 450001, China 2State Key Laboratory of Fire Science, University of Science and Technology of China, Hefei 230026, China 3Department of Building and Construction, City University of Hong Kong, Kowloon, Hong Kong, SAR China azhongwei@zzu.edu.cn Keywords: Ultrafine Water Mist; Flow behavior; Fire extinction; CFD Abstract: CFD simulation study on the fire-extinguishing performance of ultra-fine water mist (UFM) and its flow behavior in a small scale tunnel.
Numerical simulation In the numerical simulation, the k–ε turbulence model was adopted to simulate thermal plume and the air flow.
Two kinds of fire size were considered in the simulations.
Fig.1 Layout of a small scale tunnel test scenario Simulation results and anlysis Without fire Fig.2 shows the time-variation of mass fraction of ultra-fine water mist in simulation of using Dense Gas model without obstruction in the tunnel.
Fig.4a: Without fire Fig.4b: With a small size of fire Fig.4c: With a large size of fire Fig.4 The isosurface of mass fraction (the value is 0.2 and 0.1) in small scale tunnel using density gas model (simulation results at 37s) Conclusion CFD simulation results on flow behavior of ultra-fine water mist were presented in this section.

The distribution performance of original style was studied with CFD numerical simulation method and an improved distributor was proposed in this paper.
Structure schematic diagram of two distributors Numerical procedure A commercial CFD code Ansys14.5 provided by Asia-Pacific was used to calculate.
The unstructured tetrahedral grids were generated by the ICEM CFD and the boundary layer near the wall was set.
When residual value was less than1.0×10-5, the simulation was converged.
Numerical simulation of distributor in a hydrotreating reactor.

Currently, one dimensional simulation (1D), three dimensional simulation (3D) and hybrid simulation are commonly used in CFD simulation of the intake and exhaust systems.
Hybrid simulation means coupling of one and three dimensional simulation.
In this paper, CFD technology was used to optimize exhaust runner of GW15 gasoline engine.
Finally, verified simulation results though experiment. 1D Simulation 1D Modeling.
(3) In the design of exhaust runner, the performances of engine could be predicted precisely using CFD technology.

The aim of this work was to evaluate experimentally and through numerical simulations, the helical path and the axial mean velocity developed by glass beads with diameter of 2.7 mm flowing with a non-Newtonian fluid through a partially obstructed annulus.
Techniques of computational fluid dynamics (CFD) were applied to obtain detailed information about the flow field, allowing to estimate the radial position of launching of particles in the range of 35.5 mm to 39.1 mm.
Techniques of CFD were applied in order to predict the flow patterns in horizontal annular sections partially clogged and compared with the experimental data obtained by inserting particles into the flow.
The simulations were performed steady, in laminar regime using periodic flow conditions in the axial direction.
The parameters of the Herschel-Bulkley model (=3.14 Pa; =0.3864 Pa.sn e = 0.50) corresponding to the fluid studied were inserted into the viscous panel of the CFD software.

Most of the computational research interest has been focused on the simulation of the fluidized bed hydrodynamics, of multiphase flows using the Eulerian-Eulerian for non-reactive fluidized beds [3, 4] and chemically reactive flows with heat transfer.
The scope of the present simulation is to determine the heat and momentum transport inside the reactor and the chemical reactions of the palm fruit biomass particle.
The model combines the bed hydrodynamics and fast pyrolysis process in a using CFD FLUENT 12 computer code.
Nevertheless, the CFD technique may assist to optimize the design of the reactor for distributed farm scales.
Mtui: CFD Modeling of space-time evolution of fast pyrolysis products in bench-scale fluidized bed reactor.

Numerical simulation using Computational Fluid Dynamics (CFD) is considered to be a useful tool for developing reliable pressurized mixing fluid profile correlations and providing good understanding in the fluid flow mechanisms in particular reaction time and geometry of the mixer.
Details of the CFD simulation CFD model of the mixer.
The results from CFD analysis will show the more preferable pressure for significant geometry condition of the mixing zone.
In this investigation, all the significant operating condition and process arrangement applied to the 2-D CFD model for the mixer.
The current study is expected to provide the general idea of CFD application for nano-particle production at mixing stage.

When the air distribution is modelled in the ventilated space usually CFD simulation is performed and simplified boundary conditions are defined at the locations where the supply air enters the room.
Therefore the investigations were conducted with 3D CFD.
In both cases transient simulation was performed.
CFD has many deficiencies and uncertainties [10].
CFD, 2000

Theflow fields in different monsoon periodsof Shanghai Mengqing Garden were analyzed by computational fluid dynamic (CFD) simulation method.
At the same time, the wind energyvalue in the Shanghai Mengqing Garden wasalso evaluated by CFD method.
All the buildings are kept in the simulation model.
Domain Size.The domain size should be extended on the basis of the building region in the CFD analysis.
Turbulence Model.The turbulence model type is very important for the simulation accuracy of building environmental flow in CFD analysis, because the complex flow phenomena, such as separation, reattachment and vortex shedding, happen in building environmental flow [6].

The Optimization Design of the Planing Vessel’s Channel Parameters Based on the CFD Technology Hai-long SHEN1, a, Wei Lu2, b and Yu-min SU3, c 1,2,3 National Key Laboratory of Science and Technology on Autonomous Underwater Vehicle, Harbin Engineering University, Harbin 150001, China ashenhailong@hrbeu.edu.cn, bluwei@hrbeu.edu.cn, csuyumin@hrbeu.edu.cn Keywords: catamaran planning vessel;channel parameters;hydrodynamic performance;CFD Abstract:Due to the special hull shape of the catamaran planing vessel, the shiplines optimization design and the hydrodynamic performance prediction of the catamaran planing vessel are mainly carried out by model tank tests and the empirical formula at present.
In this paper, the influence of the key channel design parameters on the catamaran planing vessel hydrodynamic performance is studied based on the CFD technology.
In recent years, with the rapid development of computer calculation ability, some mature CFD methods began to play an important role in the ship hydrodynamic performance prediction, which became a kind of auxiliary means at the hydrodynamic performance test research [1, 2, 3, 4].In this paper, channel parameters’ influence on the resistance performance of the catamaran planing vessel is discussed based on the CFD technology.
Fig. 7 Resistance curves of different Fig. 11 Resistance curves of different channel relative widths channel relative heights Fig. 15 Resistance curves of different channel top deadrise angles Summary Restrictions in simulation and data probing,expenses and scale effects of experimental analysis are good reasons to employ a numerical tool as a part of ship design procedure.In this paper, the single degree of freedom movement method based on the dynamic grid technology is adopted to analyze the influence of channel parameters on the catamaran planing vessel hydrodynamic performance, which includes the channel relative width /B, the channel relative height and the channel top deadrise angle.
The numerical results show that suitable channel parameters could be getting by the numerical simulation within the suggestion scope of channel parameters.

3D numerical simulation of the airflow in a Pneumatic Splicer Xiao Xing1, a and Guoming Ye1,b 1School of Mechanical Engineering, Donghua University,Shanghai, 201620,China alilyxingxiao@hotmail.com, bygm@dhu.edu.cn Key words:pneumatic splicer ; splicing chamber ; numerical simulation ; air flows Abstract.
Three-dimensional numerical simulation is conducted and standard K-ε turbulence model is used.
This work also shows that CFD technique can provide a better understanding of the behavior of the high speed air flow in the air splicing chamber.
Jianheng Zhou and Pengfei Qin [2] applied the Computational Fluid Dynamics (CFD) technology to the design of the pneumatic splicer.
Therefore, the standard K-ε model is only appropriate for the simulation of fully turbulent flow.