Table of Contents

- Title, Disclaimer of Warranty and Liability

- Preface

- Topics in This Manual

- Topics in Other ANSYS Manuals

- Conventions This Manual Uses

- The ANSYS Product Family

- 1 Overview of FLOTRAN CFD Analyses

- 1.1 What
Is FLOTRAN CFD Analysis?

- 1.2 Types
of FLOTRAN Analyses

- 1.2.1 Laminar Flow Analysis

- 1.2.2 Turbulent Flow Analysis

- 1.2.3 Thermal Analysis

- 1.2.4 Compressible Flow Analysis

- 1.2.5 Non-Newtonian Fluid Flow Analysis

- 1.2.6 Multiple Species Transport Analysis

- 2 The
Basics of FLOTRAN Analysis

- 2.1 Characteristics of the FLOTRAN Elements

- 2.1.1 Element FLUID141

- 2.1.2 Element FLUID142

- 2.1.3 Other Element Features

- 2.2 Using
the FLOTRAN Elements: Considerations and Restrictions

- 2.2.1 Limitations on FLOTRAN Element Use

- 2.3 Overview of a FLOTRAN Analysis

- 2.3.1 Determining the Problem Domain

- 2.3.2 Determining the Flow Regime

- 2.3.3 Creating the Finite Element Mesh

- 2.3.4 Applying Boundary Conditions

- 2.3.5 Setting FLOTRAN Analysis Parameters

- 2.3.6 Solving the Problem

- 2.3.7 Examining the Results

- 2.4 Files
the FLOTRAN Elements Create

- 2.4.1 The
Results File

- 2.4.2 The
Print File (Jobname.PFL)

- 2.4.3 The
Nodal Residuals File

- 2.4.4 The
Restart File

- 2.4.5 Restarting a FLOTRAN Analysis

- 2.5 Convergence and Stability Tools

- 2.5.1 Relaxation Factors

- 2.5.2 Inertial Relaxation

- 2.5.3 Artificial Viscosity

- 2.5.4 Velocity Capping

- 2.5.5 The
Quadrature Order

- 2.6 What
to Watch For During a FLOTRAN Analysis

- 2.6.1 Deciding How Many Global Iterations to Use

- 2.6.2 Convergence Monitors

- 2.6.3 Stopping a FLOTRAN Analysis

- 2.7 Evaluating a FLOTRAN Analysis

- 2.8 Verifying Results

- 3 An
Example of FLOTRAN Analysis

- 3.1 Example of a Laminar and Turbulent FLOTRAN Analysis

- 3.1.1 The
Example Described

- 3.2 Approach and Assumptions

- 3.2.1 Dimensions and Properties

- 4 FLOTRAN Laminar and Turbulent Incompressible Flow

- 4.1 Characteristics of Fluid Flow Analysis

- 4.2 Activating the Turbulence Model

- 4.2.1 The
Role of the Reynolds Number

- 4.2.2 Determining Whether an Analysis Is Turbulent

- 4.2.3 Turbulence Ratio and Inlet Parameters

- 4.2.4 Turbulence Models

- 4.2.4.1 Standard k- Model (default)

- 4.2.4.2 Zero
Equation Turbulence Model (ZeroEq)

- 4.2.4.3 Re-Normalized Group Turbulence Model (RNG)

- 4.2.4.4 New
k- Model due to Shih (NKE)

- 4.2.4.5 Non-linear Model of Girimaji (GIR)

- 4.2.4.6 Shih,
Zhu, Lumley Model (SZL)

- 4.3 Meshing Requirements

- 4.4 Flow
Boundary Conditions

- 4.5 Strategies for Difficult Problems

- 5 FLOTRAN Thermal Analyses

- 5.1 Thermal Analysis Overview

- 5.2 Meshing Requirements

- 5.3 Property Specifications and Control

- 5.4 Thermal Loads and Boundary Conditions

- 5.4.1 Applying Loads

- 5.4.1.1 Applying Loads Using Commands

- 5.4.1.2 Applying Loads Using the GUI

- 5.4.1.3 Solutions

- 5.5 Solution Strategies

- 5.5.1 Constant Fluid Properties

- 5.5.2 Forced Convection, Temperature Dependent Properties

- 5.5.3 Free
Convection, Temperature Dependent Properties

- 5.5.4 Conjugate Heat Transfer

- 5.6 Heat
Balance

- 5.7 Examples of a Laminar, Thermal, Steady-State FLOTRAN Analysis

- 5.7.1 The
Example Described

- 5.8 Doing
the Sample Analysis (Command Method)

- 5.9 Doing
the Sample Analysis (GUI Method)

- 5.9.1 Finishing Your Analysis

- 5.10 Where
to Find Other FLOTRAN Analysis Examples

- 6 FLOTRAN Transient Analyses

- 6.1 Time
Step Specification and Convergence

- 6.2 Terminating and Getting Output from a Transient Analysis

- 6.3 Applying Transient Boundary Conditions

- 7 FLOTRAN Compressible Analyses

- 7.1 Requirements for Compressible Analysis

- 7.2 Property Calculations

- 7.3 Boundary Conditions

- 7.4 Structured vs. Unstructured Mesh

- 7.5 Solution Strategies

- 7.5.1 Inertial Relaxation

- 8 Specifying Fluid Properties for FLOTRAN

- 8.1 Guidelines for Specifying Properties

- 8.2 Fluid
Property Types

- 8.2.1 Property Types for Specific Heat

- 8.2.2 Property Types for Density and Thermal Conductivity

- 8.2.3 Property Types for Viscosity

- 8.2.4 General Guidelines for Setting Property Types

- 8.2.5 Density

- 8.2.6 Viscosity

- 8.2.7 Specific Heat

- 8.2.8 Thermal Conductivity

- 8.3 Initializing and Varying Properties

- 8.3.1 Activating Variable Properties

- 8.4 Modifying the Fluid Property Database

- 8.5 Using
Reference Properties

- 8.6 Using
the ANSYS Non-Newtonian Flow Capabilities

- 8.6.1 Activating the Power Law Model

- 8.6.2 Activating the Carreau Model

- 8.6.3 Activating the Bingham Model

- 8.7 Using
User-Programmable Subroutines

- 9 FLOTRAN Special Features

- 9.1 Coordinate Systems

- 9.2 Rotating Frames of Reference

- 9.3 Swirl

- 9.4 Distributed Resistance/Source

- 10 FLOTRAN CFD Solvers and the Matrix Equation

- 10.1 Which
Solver Should You Use?

- 10.2 Tri-Diagonal Matrix Algorithm

- 10.3 Semi-Direct Solvers

- 10.3.1 Preconditioned Generalized Minimum Residual (PGMR)

Solver

- 11 Multiple Species Transport

- 11.1 Overview of Multiple Species Transport

- 11.2 Mixture Types

- 11.2.1 Dilute Mixture Analysis

- 11.2.2 Composite Mixture Analysis

- 11.2.3 Composite Gas Analysis

- 11.3 Doing
a Multiple Species Analysis

- 11.3.1 Establish the Species

- 11.3.2 Choose an Algebraic Species

- 11.3.3 Adjust Output Format

- 11.3.4 Set
Properties

- 11.3.5 Specify Boundary Conditions

- 11.3.6 Set
Relaxation and Solution Parameters

- 11.4 Doing
a Heat Exchanger Analysis Using Two Species

- 11.5 Example Analysis Mixing Three Gases

- 12 Advection Discretization Options

- 12.1 Introduction

- 12.2 Using
SUPG

- 12.3 Strategies for Difficult Solutions