Week 1: Channel flow simulation using CONVERGE CFD

Week - 1

Channel Flow Simulation

Aim :

• To perform a Channel flow simulation in Converge 3.0

Workflow in Converge:

1. Geometry.
2. Mesh.
3. Case setup.
4. Solution.
5. Results.

Geometry:

• Open the Converge studio 3.0.
• Choose create tool under Geometry section and then select Box tool under create option.
• After that we need to provide the dimensions for the Geometry.
• In this case the geometry is created with the following dimensions. Centre ( 0'0'0) dx,dy,dz ( 0.1,0.01,0.01).
• By default all the dimensions in Convergeare in meters.

Mesh :

• Mesh is the process of Discretizing a large single geometry into number of elements.
• More refined mesh gives more accurate and good results.
• In this case we need to perform a simulation with 3 different mesh sizes.
• For this case we need to perform a simulation with base mesh of element size,
• dx = 2e-4m, dy = 2e-4m, dz = 2e-4m.

Case Setup:

• First we need to choose the Application type as Time based.
• Choose the Material as Air.
• After that leave the Gas simulation and Global transport equation as default.
• Add the O2 and N2 in the species.
• Under Simulation parameters choose the steady state solver and then provide the maximum and min time cycles.
• Run Parameters:
  Solver - Steady state
  Simulation mode - Full hydrodynamic
  Gas Flow Solver - Compressible.
• Simulation time parameters:
  Start time - 0 cycles
  End time - 15000 cycles
  Initial time step - 1e-9 s
  Minimum time step - 1e-9 s
  Maximum time step - 1 s
  Maximum Convection CFL limit - 1
• Solver Parameters:
  Solver scheme - PISO
  Solver type - Density based
• Boundary conditions:
  Inlet - Inflow (100001 pa and 300 K)
  Outlet - Outflow (100000 pa)
  Top-Bottom-Walls - Wall (No slip)
  Front-2D - Two-D
  Back-2D - Two-D

• After assinging the boundary conditions we need to assign the regions for al the boundaries.
• We need to create a region to initialize the setup.
• The initial pressure and then the Inlet pressure should have to be same.
• After that we need to uncheck the turbulence model. In this simulation we know that the flow is laminar so we don't need a turbulence model here.
• Output/Post processing
  In this part we need to choose the variable which we want to plot.

Solution:

• After setting up the case in Converge, we have to save the setup file
• Aftet that we have to export the input files.
• After exporting the files we have to open CYWIN to perform the simulation.
• In the CYGWIN, we need to choose the directory at where we exported the input files.
• Then we have to copy and paste the location of intelmpi\converge.exe.

Results:

Mesh Image :

Mass flow rate plot :

Inlet:

Outlet:

Pressure plot :

Inlet :

Outlet :

Total cells:

Velocity plot :

Inlet:

Outlet:

Velocity Contour :