《CFX5.5培训资料》（英文版）Introduction

CFX! Introduction CFX5.5V5.5.1H 2001AEA Technology

CFX 5.5 V 5.5.1H © 2001AEA Technology 1-1 Introduction

CFX! Computational Fluid Dynamics(CFDy Simulation of fluid flow, heat transfer and mass transfer processes CFD involves the numerical solution of the governing equations ass continuity Momentum Energy Turbulent quantities Scalar/mass fraction These equations are solved locally at discrete locations(nodes) throughout the domain Hexahedral Tetrahedra Wedge( Prism) Pyramid CFX5.5V5.5.1H 2001AEA Technology

CFX 5.5 V 5.5.1H © 2001AEA Technology 1-2 Computational Fluid Dynamics (CFD) Simulation of fluid flow, heat transfer and mass transfer processes CFD involves the numerical solution of the governing equations - Mass continuity - Momentum - Energy - Turbulent quantities - Scalar/mass fraction These equations are solved locally at discrete locations (nodes) throughout the domain Hexahedral Tetrahedral Wedge (Prism) Pyramid

CFX! Benefits of cfd Experimental methods are usually costly Non-intrusive safe testing Data available throughout the domain velocity components, pressure, temperature, etc Insight gained into flow field which is difficult to measure Used as a“ what if’tool Scale up issues are eliminated This means Shorter design time and lower design costs Competitive advantage CFX5.5V5.5.1H 2001AEA Technology

CFX 5.5 V 5.5.1H © 2001AEA Technology 1-3 Benefits of CFD Experimental methods are usually costly Non-intrusive, safe testing Data available throughout the domain - velocity components, pressure, temperature, etc ... Insight gained into flow field which is difficult to measure Used as a “what if” tool Scale up issues are eliminated This means… Shorter design time and lower design costs Competitive advantage

CFX! Main Steps in CFDAnalysis Step I: Pre-processing step- define the problem - CFX-Build Define the geometry Define the domain(s) Define boundary and initial conditions Define the mesh Define solver parameters Step ll: Solution step-CFX-Soly solve the governing equations Step Ill: Post-processing step CFX-Post analyse results CFX5.5V5.5.1H 2001AEA Technology

CFX 5.5 V 5.5.1H © 2001AEA Technology 1-4 Main Steps in CFD Analysis Step I: Pre-processing step - define the problem - CFX-Build - Define the geometry - Define the domain(s) - Define boundary and initial conditions - Define the mesh - Define solver parameters Step II: Solution step - CFX-Solve - solve the governing equations Step III: Post-processing step CFX-Post - analyse results

CFX! Step 1: Pre-processing Define the geometry Domain in which the governing equations will be solved and solution obtained Create a B-rep solid Define the fluid domain Create fluid regions(fluid solid, conducting solid, porous meala Assign fluid properties (viscosity, thermal conductivity, specific heat, etc...) Select the physical models (turbulence models compressibility, buoyancy, two- phase flow, etc CFX5.5V5.5.1H 2001AEA Technology

CFX 5.5 V 5.5.1H © 2001AEA Technology 1-5 Step I: Pre-processing Define the geometry - Domain in which the governing equations will be solved and solution obtained - Create a B-rep Solid Define the fluid domain. - Create fluid regions (fluid, solid, conducting solid, porous media) - Assign fluid properties (viscosity, thermal conductivity, specific heat, etc…) - Select the physical models (turbulence models, compressibility, buoyancy, two￾phase flow, etc…)

CFX! Step 1: Pre-processing Define the boundary conditions Needed on all external surfaces of geometry OUTLET (0.0Pa) WALL (adiabatic INLET1 (0.5m/s@185K) INLET2 S0m/s@31K) CFX5.5V5.5.1H 2001AEA Technology

CFX 5.5 V 5.5.1H © 2001AEA Technology 1-6 Step I: Pre-processing Define the boundary conditions - Needed on all external surfaces of geometry

CFX! Step 1: Pre-processing Grid generation Process of generating finite volumes or cells Tetrahedral/Pyramidal/Prismatic/Hexahedral cells created Surface mesh and volume mesh make up the grid 1-7 CFX5.5V5.5.1H 2001AEA Technology

CFX 5.5 V 5.5.1H © 2001AEA Technology 1-7 Step I: Pre-processing Grid Generation - Process of generating finite volumes or cells - Tetrahedral/Pyramidal/Prismatic/Hexahedral cells created - Surface mesh and volume mesh make up the grid

CFX群 Step ll: Solution Procedure Solve the governing equations Set the flow solver options Iteratively solve the Mass/Momentum -RMS Residuals governing equations as a batch process Normalised Log residual 0.0 Obtain convergence U-Mom 1.0 V-Mom 2.0 W-Mom 4.0 5.0 6,0 Iteration Number CFX5.5V5.5.1H 2001AEA Technology

CFX 5.5 V 5.5.1H © 2001AEA Technology 1-8 Step II: Solution Procedure Solve the governing equations - Set the flow solver options - Iteratively solve the governing equations as a batch process - Obtain convergence

CFX! Step Il Post-processing Examine results Either in numerical or graphical format X 1-9 CFX5.5V5.5.1H 2001AEA Technology

CFX 5.5 V 5.5.1H © 2001AEA Technology 1-9 Step III: Post-processing Examine results - Either in numerical or graphical format

CFX! Import Fe eatures of cFX-5 Integrated geometry and grid generation CAD import capability CATIA, Unigraphics, Pro/Engineer, Euclid3, CADDS5 Parasolid. ACIS IGES Patran Automatic meshing Element based finite volume method Robust, accurate coupled algebraic multigrid solver Scalable performance in parallel CFX Expression Language(CEL) CFX Command Language(CCl) Interface to other software 1-10 CFX5.5V5.5.1H 2001AEA Technology

CFX 5.5 V 5.5.1H © 2001AEA Technology 1-10 Import Features of CFX-5 Integrated geometry and grid generation CAD import capability - CATIA, Unigraphics, Pro/Engineer, Euclid3, CADDS5, - Parasolid, ACIS, IGES, Patran Automatic meshing Element based finite volume method Robust, accurate coupled algebraic multigrid solver Scalable performance in parallel CFX Expression Language (CEL) CFX Command Language (CCL) Interface to other software