Channel flow simulation using CONVERGE CFD

Abstract
In this project, simple channel flow was simulated using CONVERGE Studio and compare the results of three different mesh grid size. Then it was post-processed in ParaView to understand the results visually. CYGWIN was used to run the commands for simulation and convering the files for the post-processer.

Introduction
The purpose of this simulation was to affirm that the internal laminar flow velocity has parabolic profile due to wall shear, and to understand the software, methods, and process of simulation.

Methods
The channel flow was created in CONVERGE Studio. The geometry dimension are 0.1m x 0.01m x 0.01m. Once the geometry is established, Figure 1, the normals of the plane are then inversed toward the flow using the Normal option under Transform. Final step before case setup is to diagnosis the geometry for any open edges or normals. For simple geometry like figure 1, this should not create any issue.

Figure 1. Channel flow geometry in CONVERGE Studio.

Case Set-up
Application: General Flow
Materials: Air mixture with Nitrogen and Oxygen as species.
Simulation Parameters: Pressure base steady solver (Run Parameter), 15000 cycles with 1E-09 minimun and inital time step (Time Parameters).
Boundary Conditions:

• One Y-Z plane as INLET with 100,001 Pascal pressure with air mixture.
• One Y-Z plane as OUTLET with 100,000 Pascal pressure with air mixture.
• Both X-Y plane as WALLS with no-slip condition
• Both X-Z plane as TWO_D

Regions and Initialization: User define region is assigned to all boundary flag to create volumetric region. Concentration of air is reversed (0.23 N2 and 0.77 O2).
Physical Models: Turbulance is turn off.
Base Grid: Given as follow

• Case 1: dx=dy=dz = 2E-4m.
• Case 2: dx=dy=dz = 1.5E-4m.
• Case 3: dx=dy=dz = 1.0E-4 m.

Output/Post Processing: Default/ Turbulance parameters are turned off.

Results and Discussion

Figure 2.1. Case 1 velocity contour at last cycle.

Figure 2.2. Case 2 velocity contour at last cycle.

Figure 2.3. Case 3 velocity contour at last cycle.

Figure 3.1. Case 1 pressure contour at last cycle.

Figure 3.2. Case 2 pressur contour at last cycle.