# Parametric Analysis in ANSYS Workbench Using ANSYS FLUENT

### Introduction

This tutorial illustrates using ANSYS Workbench to set up and solve a three-dimensional turbulent fluid flow and heat transfer problem in an automotive heating, ventilation, and air conditioning (HVAC) duct system using an ANSYS FLUENT fluid flow system. ANSYS Workbench uses parameters and design points to allow you to run optimization and what-if scenarios.You can define both input and output parameters in ANSYS FLUENT that can be used in your ANSYS Workbench project.You can also define parameters in other applications including ANSYS DesignModeler and ANSYS CFD-Post. Once you have defined parameters for your system, a Parameters cell is added to the system and the Parameter Set bus bar is added to your project.This tutorial is designed to introduce you to the parametric analysis utility available in ANSYS Workbench.
The tutorial starts with a Fluid Flow (FLUENT) analysis system with pre-defined geometry and mesh components.Within this tutorial, you will redefine the geometry parameters in ANSYS DesignModeler by adding constraints to the input parameters.You will use ANSYS FLUENT to set up and solve the CFD problem.While defining the problem set-up, you will also learn to define input parameters in ANSYS FLUENT.The tutorial will also provide information on how to create output parameters in ANSYS CFDPost.
This tutorial demonstrates how to do the following:

• Add constraints to the ANSYS DesignModeler input parameters.
• Create an ANSYS FLUENT fluid flow analysis system in ANSYS Workbench
•  Set up the CFD simulation in ANSYS FLUENT, which includes
• Setting material properties and boundary conditions for a turbulent forced convection problem.
• Defining input parameters in FLUENT
• Define output parameters in CFD-Post
• Create additional design points in ANSYS Workbench.
• Run multiple CFD simulations by updating the design points.
• Analyze the results of each design point project in ANSYS CFD-Post and ANSYS Workbench.

### Problem Description

In the past, evaluation of vehicle air conditioning systems was performed using prototypes and testing their performance in test labs. However, the design process of modern vehicle air conditioning (AC) systems improved with the introduction of Computer Aided Design (CAD), Computer Aided Engineering (CAE) and Computer Aided Manufacturing (CAM).The AC system specification will include minimum performance requirements, temperatures, control zones, flow rates etc. Performance testing using CFD may include fluid velocity (air flow), pressure values, and temperature distribution. Using CFD enables the analysis of fluid through very complex geometry and boundary conditions.
As part of the analysis, a designer can change the geometry of the system or the boundary conditions such as the inlet velocity, flow rate, etc., and view the effect on fluid flow patterns.This tutorial illustrates the AC design process on a representative automotive HVAC system consisting of both an evaporator for cooling and a heat exchanger for heating requirements.

### Postprocessing the New Design Points in CFD-Post

In this step, you will open the ANSYS Workbench project for each of the design points and inspect the vector plots based on the new results of the simulations.

• Study the results of the first design point (DP1).
Open the ANSYS Workbench project for the first design point (DP1).
In your current working folder, double-click the fluent-workbench-param_dp1.wbpj file to open ANSYS Workbench.
• Open CFD-Post by double-clicking the Results cell in the Project Schematic for the Fluid Flow (FLUENT) analysis system.
• View the vector plot colored by pressure. Ensure that Range in the Color tab is set to Global.

### Summary

In this tutorial, input and output parameters were created within ANSYS Workbench, ANSYS FLUENT, and ANSYS CFD-Post in order to study the airflow in an automotive HVAC system. ANSYS FLUENT was used to calculate the fluid flow throughout the geometry using the computational mesh, and ANSYS CFD-Post was used to analyze the results. ANSYS Workbench was used to create additional design points based on the original settings, and the corresponding simulations were run to create separate projects where parameterized analysis could be performed to study the effects of variable angles of the inlet valves, velocities, and temperatures. Also, note that simplified solution settings were used in this tutorial to speed up the solution time. For more improved solution accuracy, you would typically use denser mesh and higher order discretization for all flow equations.