火灾爆炸分析与计算

Systems with Strong Buoyant Forces
Dr. Walter Schwarz Airpak Product Manager
Seminar 42: Issues of CFD Applications in Tunnels ASHRAE Winter Meeting February 9, 2000 Dallas, Texas
Fire Scenarios in the Budapest Sports Arena
The new Budapest Sports Arena
Engineers perform a fire test inside the arena
Contours of temperature on a surface of 1% CO2 concentration, 10 minutes after ignition,
Depend on the specific purpose and flow conditions of the
problem, different CFD codes can be chosen for different applications (aerospace, marines, combustion, multi-phase flows, etc.)
View looking south +
computational mesh
Boundary Conditions
Initial conditions
temperature 277.6 K velocity 0 m/s
North & South Portals treated as pressure openings
Sports
Oil & Gas
Flow of lubricating mud over drill bit
Power Generation
Flow around cooling towers
Aerospace
Industry
• Drag and Lift Coeff. • Rocket • Compressor-Turbine • Tank Sloshing • Combustion Chamber • Seat Ejector • Cooling • Anti-Icing • Trust Reverser
Turbomachina ry Industry
• Rotor-Stator Interaction • Multistage Compressor • Multistage Turbine • Torque requirment • Pump • Fan
Fluent组件关系
CFD process
Simulated full-scale natural ventilation tests which were part of the Memorial Tunnel Fire Ventilation Test Program (ASHRAE Technical Data Bulletin Vol. 13 No. 1, 1997)
Overview
Wanted to see how reliable transient CFD predictions of buoyant smoke movement in tunnels really are Behavior of the transient bi-directional flow transition to natural ventilation speed of smoke propagation Comparisons at a particular time smoke distribution temperature distribution flow patterns velocity magnitudes
F&EI及危险等级
实例分析
表８-１２ 氧化反应工艺单元火灾爆炸指数表 07KP5
第二节 火灾模拟
ALOFT-FT
ALOFT-FTTM 是预测大的室外火的烟气颗 粒和燃烧产物在顺风方向分布的计算模 型。NIST发布。
用于水面原油燃烧过程烟羽模型
火灾参数输入
风参数输入
Automotive
Biomedical
Temperature and natural convection currents in the eye following laser heating.
Where is CFD used?
Where is CFD
used?
• Aerospacee • Automotive • Biomedical • Chemical
• Aerospace • Automotive • Biomedical
• Chemical Processing • HVAC • Hydraulics • Marine • Oil & Gas • Power Generation • Sports
Aerospa ce
F18 Store Separation
Smoke, represented by a gray iso-surface, penetrates into many occupied areas of a building with a complex atrium
The same fire scenario as above, but with a smoke management system that segregates the atrium
loss coefficient 0.5 static pressure 101325 Pa turbulence intensity 5% turbulent viscosity ratio 5
FARSITE
FARSITE是利用地形和燃料的空间信息以 及天气与风的条件的火灾发展模型，它 将现有的地表火、树冠火、飞火及火加 速等模型集成到一个二维火灾发展模型 中。用户必须有地理信息系统的支持。 目前已经发布4.0的版本。USDA Forest Service发布。
场模拟法
FDS
effects.
Hydraulics
HVAC
Streamlines for workstation ventilation
Where is CFD used?
Marine (movie)
Where is CFD used?
• Aerospace • Automotive • Biomedical • Chemical Processing • HVAC • Hydraulics • Marine • Oil & Gas • Power Generation • Sports
Processing • HVAC • Hydraulics • Marine • Oil & Gas • Power Generation • Sports
Chemical Processing
Polymerization reactor vessel - prediction
of flow separation and residence time
Smoke Movement
Pathlines coloured by temperature
Smoke Movement
Gas cloud
Gas Dispersion from a Cooker
Dispersion from a Cooker
Containing Smoke in Complex Atria
Once purposes and CFD codes chosen, “CFD process” is the
steps to set up the IBVP problem and run the code:
1. Geometry
2. Physics 3. Mesh 4. Solve 5. Reports 6. Post processing
Full-scale experimental test programs are expensive
Application of computational methods to these problems requires consideration of
conservatism realism uncertainties
温度参数输入
计算输出
PM10颗粒水平向浓度
PM10颗粒竖直向浓度
BEHAVEPlus
BEHAVEPlus是预测野火行为的应用软件， 用于野火管理。用户是野火管理者，必 须熟悉燃料、地形、野火状况以及相应 的地形等。BEHAVEPlus代替了1984年 Dos版的BEHAVE，升级了算法和图形用 户界面。USDA Forest Service发布。
CFD Process
Geometry
Physics
Mesh
Select Geometry
Geometry Parameters
Domain Shape and
Size
Heat Transfer ON/OFF
Compressibl e
ON/OFF
Flow properties
Viscous Model
MTFVTP Natural Ventilation
Geometry
Tunnel downgrade 3.2% from north to south
ceiling removed
length 853 m (2800 ft)
cross-sectional area
59.6 m2 (642 ft2)
Numerical Scheme
Reports
Forces Report (lift/drag, shear stress, etc)
XY Plot
Verification
Validation
PostProcessin
g
Contours
Vectors
Streamlines
Initial Conditions
第八章 火灾爆炸分析与计算
内容
第一节 火灾爆炸指数评价法 第二节 火灾模拟 第三节 爆炸计算
火灾爆炸指数评价法：道化学公司
1.工艺单元的选择 2.物质系数的确定 3.工艺单元危险系数 4.火灾爆炸危险指数的计算 5.安全措施补偿系数(C１C２C３) 6.危险半径与危险暴露区域面积 7.暴露区域内财产价值 8.危害系数的确定 9.基本最大可能财产损失(Basis 10.实际最大可能财产损失(Actual11.最大可能工作日损失 (MPDO) 12.最大可能停产损失(BI)
FDS 预测由火、风、通风系统等所引起 的烟或/和空气流的运动。目前已经发布 2.0版本。Smokeview将NIST FDS的预测 结果图形化显示出来。NIST发布。
2D
3D
3D
Where is CFD used?
Where is CFD used?
Computational Fluid Dynamics
Purposes of CFD codes will be different for different applications:
investigation of bubble-fluid interactions for bubbly flows, study of wave induced massively separated flows for free-surface, etc.
Unstructured (automatic/
manual)
Structured (automatic/
manual)
Boundary Conditions
Solve
Steady/ Unsteady
Iterations/ Steps
Convergwk.baidu.comnt Limit
Precisions (single/ double)
ISSUES
Development of reliable emergency tunnel ventilation design and emergency operational procedures requires experience with and/or knowledge of fire smoke behavior