Ansys Fluent

Tutorial 1. Introduction to Using ANSYS FLUENT in ANSYS Workbench: Fluid Flow and Heat Transfer in a Mixing Elbow
Introduction
This tutorial illustrates using ANSYS Workbench to set up and solve a three-dimensional turbulent fluid flow and heat transfer problem in a mixing elbow using ANSYS FLUENT fluid flow systems. This tutorial is designed to introduce you to the ANSYS Workbench tool set using afamiliar geometry (the first tutorial in the separate Tutorial Guide). Within this tutorial, you will create the elbow geometry and the corresponding computational mesh using the geometry and meshing tools within ANSYS Workbench. You will use ANSYS FLUENT to set up and solve the CFD problem, then visualize the results in both ANSYS FLUENT and the ANSYS CFD-Post postprocessing tool. Somecapabilities of ANSYS Workbench (e.g., duplicating fluid flow systems, connecting systems, and comparing multiple data sets) are also examined in this tutorial. This tutorial demonstrates how to do the following: • Launch ANSYS Workbench. • Create an ANSYS FLUENT fluid flow analysis system in ANSYS Workbench. • Create the elbow geometry using ANSYS DesignModeler. • Create the computational mesh for the geometryusing ANSYS Meshing. • Set up the CFD simulation in ANSYS FLUENT, which includes: – Set material properties and boundary conditions for a turbulent forced convection problem. – Initiate the calculation with residual plotting. – Calculate a solution using the pressure-based solver. – Visually examine the flow and temperature fields using ANSYS FLUENT (and ANSYS CFD-Post). • Create a copy of theoriginal ANSYS FLUENT fluid flow analysis system in ANSYS Workbench.

Release 12.1 c ANSYS, Inc. September 10, 2009

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Introduction to Using ANSYS FLUENT in ANSYS Workbench: Fluid Flow and Heat Transfer in a Mixing Elbow

• Change the geometry in ANSYS DesignModeler, using the duplicated system. • Regenerate the computational mesh. • Recalculate a solution in ANSYS FLUENT. • Compare theresults of the two calculations in ANSYS CFD-Post.

Prerequisites
This tutorial assumes that you have little to no experience with ANSYS DesignModeler, ANSYS Meshing, ANSYS FLUENT, or ANSYS CFD-Post, and so each step will be explicitly described.

Problem Description
The problem to be considered is shown schematically in Figure 1.1. A cold fluid at 293.15 K flows into the pipe through a largeinlet, and mixes with a warmer fluid at 313.15 K that enters through a smaller inlet located at the elbow. The pipe dimensions, the fluid properties and boundary conditions are given in SI units. Note: Since the geometry of the mixing elbow is symmetric, only half of the elbow needs to be modeled.

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Release 12.1 c ANSYS, Inc. September 10, 2009

Introduction to Using ANSYS FLUENT in ANSYSWorkbench: Fluid Flow and Heat Transfer in a Mixing Elbow

Density: Viscosity: Conductivity: Specific Heat:

ρ µ k Cp

= = = =

1000 kg/m3 8 x 10 −4 Pa−s 0.677 W/m−K 4216 J/kg−K

8"

4"

Ux = 0.4 m/s T = 20oC I = 5%

4" Dia. 3" 8"

1"

1" Dia. Uy = 1.2 m/s T = 40oC I = 5%

Figure 1.1: Problem Specification

Release 12.1 c ANSYS, Inc. September 10, 2009

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Introductionto Using ANSYS FLUENT in ANSYS Workbench: Fluid Flow and Heat Transfer in a Mixing Elbow

Setup and Solution Preparation
1. Download elbow-workbench.zip from the User Services Center to your working folder. This file can be found by using the Documentation link on the ANSYS FLUENT product page. 2. Unzip elbow-workbench.zip. The .zip file contains a folder (elbow-workbench) that in turn containstwo geometry files (elbow-geometry.agdb and elbow-geometry.stp) along with an ANSYS Workbench project file (elbow-workbench.wbpj) and a corresponding project folder (elbow-geometry files) that contains supporting files for the project (e.g., solution and results files). Note: ANSYS FLUENT tutorials are prepared using ANSYS FLUENT on a Windows system. The screen shots and graphic images in the...