odd成形技术之数值模拟与模拟实验设计理论依据

1、ODD成形技术之数值模拟与模拟实验设计之理论依据Mars2014/04/03Content什么昰电脑模拟ODD技术的电脑模拟模拟与相似实验设计的理论WhatisSimulation?(什么昰模拟)Simulation is the imiion of a dynamic systemusing a computerminorderto evaluateandimprove system performance模拟乃是使用电脑模型来模仿一个动态系统为了评估与改善系统之执行成效Simulation isin such a way of the actualover timethe ming of

2、a pros or systemthe response take placet the mmimicssystem to eventst模拟乃是使用电脑模型来模仿真正系统建模之过程。此系统是会随时间之改变而变化之系统(即动态系统)WhySimulate?(为什么要模拟)Simulationprovidesawaytovalidatethebestdecis.模拟提供一种验证最佳决策之方法Simulationconsuming,avoidsexpensive,time-anddisruptivetrial-and-errortechniques模拟避免昂贵，费时及破碎式的试误法Characte

3、risticsofSimulation(模拟之特性)Capture systemer-dependencies掌握系统间各元件之相依性Account for variability in system解释系统中之变异性Versatile enough to many system多方面的功能可以对任何系统建立模型Shows behavior over time解释与显示系统随时间变化之行为Less costly, time, disruptivesystemn experimenton the actual比起在真正系统上寻找Visually appealing，模拟负担较少之成本，时间视觉之

4、加分效果Easy results结果易分析Run in compressed, real time 执行结果耗费较少时间即可获得UseofSimulation之原因)(模拟Increased awareness andtechnologyunderstanding of simulation对模拟技术了解越来越普遍Increased availability, capability and simulation softwareease ofuse模拟之发展越来越容易获得与使用Increased computer memory & prosingspeeds,espelly PCs电脑存贮器与

5、处理速度不断进步Decline hardware & software costs电脑与硬件成本之减少WhenSimulationisAppropriate?(何时适用模拟之应用)Operational (logical or作业型之决策:逻辑与定量型之问题ive) deciWell defined & repetitive完整定义与重复性分析过程ytical prosNot for Qualiive Problems定性问题，如机器之可靠度，(员工士气之等并不适用)Activities & Events:er-dependency & variability系统中之活动与事件具有相依性与互动

6、性)Cost of deci cost of simulation决策成本 模拟成本Cost of experiment cost of simulation实验成本 模拟成本ComparisonofSystemCostswith&withoutSimulation(模拟与成本之关系)Allow making mistakes & working on errors on the在建模過程出錯mHowSimulate? (如何作模拟)s which will be simulated.Understanding the pro先了解要模拟什么 ?什么事你要模拟的重点?Build the mat

7、hematical m建立数值运算方式.Solve the mby numerical method.处理及运算数值程序Display the results by graphics.处理计算结果Criteria andyze the prediction验证及分析计算结果ApplicationsofSimulation(模拟之应用)ApplicationsofSimulation(模拟之应用)ODD技术的电脑模拟GlassGlass proofSimulation(玻璃模拟)s physical behaveFluid MechanicsMass TransferHeat TransferS

8、olidificationStress-StrainNumerical Method of fluid之数值分析Mech网格分割FiniteFinite FiniteElement MethodVolume MethodDifferenceMethodFreevolume流体液面追踪MAC (Marker and Cell)VOF (Volume-of-Fluid)wi,j,k+1/2vi,j+1/2,kFi,j,kPi,j,kui+1/2,j,kSimulation Fluids parameter setupSimulation Physics parameter setupFluids

9、density=2.4 g/cm3Fluids viscosity=60,000 poiset only consider Gravity、Surface tenInstofthe trough and Viscosity 、Laminar flow of fluids .Simulation 3D mesh susSimulation 2D mesh susMesh areaTotal number of real cells = 530,312Mesh areaTotal number of real cells = 21,365,200Study a haft ofsymmetry st

10、ructureStudy center ofgeometry structureFluids inletFluids inletAfter mesh sus of 3DAfter mesh s2D structureus ofsymmetry structureSimulation 2D & 3D m result of the trough2D mresultat 308 second.(2 working day)Fluids inlet3D mresultat 308 second.(10 working day)3D mcanstudy overflowsus.Trough study

11、R=?=?不同转角半径的影响(V=0.13cm/s，viscosity=60000poise)R=10mmD=11mmR=20mmD=11.3mmR=30mmD=11.8mmViscosity = 60000 (Poise)， Inlet velocity = 0.12 (cm/s)= 600Angle of Fuangle 500FuDHPS simulation study.Fn.ST1RF12CT133D mST2CT48ST3setup from initial 2D layout.Pt diameter or some critical inf. got form EG talkin

12、g.13m2D study due to size effect.4T/dinInlet V=0.5cm/s(0.18)Inlet T=965 (980)模拟与相似实验设计的理论数值模拟虽较方便，但需靠水工模型试验或实地量测数据进行方式之参数检定(Calibration) 与结果验证(Verification)。(1)几何相似(Geometric Similarity)：指模型(M间之几何尺寸成比例。)与原型(Prototype)(2)运动相似(Kinematic similarity)：指模型与原型间相对应点之速度与加速度成比例。(3)动力相似(Dynamic Similarity)：指模型

13、与原型间相对应点所受之各种外力成比例。外力可为分力或合力(各种分力包括：gravity，viscous，prere.)完整之模型相似，须同时符合三者：几何.运动.动力相似若要达到“动力完全相似”，必须模型与原型之所有无因次参数要相等，即 (Re)p= (Re)m，(Fr)p= (Fr)m，(Eu)p= (Eu)m，(W)p= (W)m，(M)p= (M)m但模型试验要符合每一种相似律在实际上十分，且几乎不可能！所以通常只考虑流场中最重要之特性，而要求其相似。Glass flow priority：黏滞力 Reynolds相似律， (Re)p= (Re)m重力 Froude相似律， (Fr)p = (Fr)m压力 Euler 相似律， (Eu)p = (Eu)m表面张力 Weber 相似律， (W)p = (W)mSummary(结论)Simulation itself is not a solution tool but an evaluation tool模拟本身不昰一种求解工具而是一种评估工具Simulation iserful to improve system perfo