Channel Flow Analysis

Objective

Setting up and analysis of a 2D channel flow considering the following mesh sizes.

The analysis will provide insights on the following parameters

1. Mesh profile
2. Velocity profile
3. Pressure profile
4. Mass flow rate
5. Total cell count

Introduction

Converge Studio is the flagship model from Convergent Science which is widely used for CFD application. With its advanced physical models and high-performance computing, it provides an easy to interact GUI and focuses on applications in IC engines, gas turbines, exhaust treatment, and general flow.

In this project, Converge Studio was used to establish a working idea of airflow simulation through a channel flow under certain parameters, which will be elaborated systematically in this report.

The flow of information in this report will be as follows

1. Parameters
2. Case Setup
   a. Preprocessing
   b. Solver
   c. Postprocessing
3. Animation
4. Inference

1. Parameters

Dimension: (0.1 x 0.01 x 0.01)m

Boundary Condition:

Due to a very lower pressure difference between the inlet and outlet, turbulence flow is neglected. With 1 Pa of pressure, it can be assumed that flow is laminar and considering turbulence flow for the analysis would add unnecessary computational cost.

1. Case Setup

The geometry for the channel flow was designed in the Case Setup window of the Converge.

a. Preprocessing

In this section, we basically set up the base structure for our geometry and provide necessary operating conditions to it.

Upon creation of the geometry, boundary conditions were defined on the respective faces of the geometry namely Inlet, Outlet, Top-Bottom, Front 2D and Back 2D.

With the completion of the above process, the case was set up with the necessary parameters as follows

2e-4

1.5e-4

1e-4

b. Solver

Once the setup was done, the files were exported to an allocated folder for processing. Processing was carried out using Cygwin, a DOS environment which extracts the information from the exported files to process the simulation and create an output folder, which was then used to create log files to perform graphical visualization of the simulation for analysis.

c. Postprocessing

The output files from Cygwin was then used to process a log file consisting of all the information of the simulation which will be required to produce a visual for the analysis. Converge Post-Processing 3D window helps to perform this task. However, both compatible Cygwin and Windows Command Prompt can also aid in performing the same task in the DOS environment. The advantage of using Converge Post-Processing 3D is that it provides a more interactive and easier environment to perform the task of unfurling and combining the information. Once the post-processing was performed, a group ParaView compatible file was generated which was used to produce the graphical visualization. ParaView is a graphical user interface used to produce graphical outputs to the simulation performed on Cygwin using the data from Converge Case Setup. Upon generation of the 2D channel flow based on the simulation output, the mesh profile, velocity profile and pressure profile for each mesh sizes were studied.

Mesh Profile

2e-4

1.5e-4

1e-4

Velocity Profile

2e-4

1.5e-4

1e-4

Pressure Profile

2e-4

1.5e-4

1e-4

Mass Flow Rate

2e-4

1.5e-4

1e-4

Total Cell Count

Animation

Inference

1. From the plots, it can be seen how the size of mesh can affect the performance of the simulation and also in the application of the final output data. For velocity, the cycle required to reach steady state increases with the decrease in the mesh size. A similar trend can be noticed with the pressure profile, the cycle required for the pressure to damp increases with decrease in mesh size.

2. Disturbance in the plots can be noticed which is because of the initial conditions in the volumetric region which damps with the due course of the cycle.

3. We can also notice that for finer mesh sizes the system couldn't reach a steady state which can be overcome by increasing the cycle.

4. Computational cost increases with the decrease of the mesh size.

5. Furthermore, more information on the characteristics of the flow can be gathered with finer mesh size.