Week 9: Project 1 - Surface preparation and Boundary Flagging (PFI)

Aim - Surface preparation and Boundary Flagging (PFI)

Introduction-

The purpose of the task is to do boundary flagging and surface preparation for the given geometry. After that, we will run the simulation for no hydrodynamic case setup and see the motion of the piston and valves in the cylinder for better understanding.

Steps –

1. Geometry
2. Define the boundary
3. Case setup
4. Simulation
5. Post-processing
6. Outputs
7. Conclusion

Geometry –

Import the file in the converge.

1. From the diagnosis, it is seen that our geometry I shaving problem in the triangle as shown in the above figure.
2. Intersection error of geometry is corrected by translating the parts.
3. Normal orientation error of geometry is corrected by translating the normal.
4. Open edges of geometry are corrected with the repair command.

After boundary flagging and surface preparation our geometry looks as shown below,

Case setup –

Application type –

Choose a Crank angle-based application type. Enter the cylinder bore stroke and other details from the engine specification sheet.

Predefined mixture

Gas simulation –

Select the Redlich Kwong equation for gas simulation. the critical temperature and pressure are already pre-defined. Import the therm.dat file in gas thermodynamic data.

Global transport parameter –

Turbulent Prandtl no and Schmidt no are mentioned below.

Reaction mechanism –

For reachion mechanism import mech. Dat file for reaction data of all species.

Simulation Parameter –

Run parameter –

We will run the simulation for the transient solver. The simulation mode will be no hydrodynamic.

simulation time parameters-

start time and end time for the simulation will be as follow.

Solver parameters- Default

Boundary condition –

The boundary condition for the different boundary is as follow –

1. Piston

1. Inflow

1. Liner

1. Head

1. Ext port

1. Outflow

1. Ext valve top

1. Ext valve angle boundary

1. Ext valve bottom boundary

1. Inlet port

1. inlet valve bottom boundary

1. inlet valve angle boundary

1. inlet valve top

1. spark plug terminal

1. spark plug

1. inlet port2

Initial condition and events –

Basically as per geometry 4 regions are defined as is

1. intake port1

1. intake port2

1. exhaust region

1. cylinder region

Events –

As per the valve timing of the inlet and exhaust valve the cylinder region has to be connected and disconnected. events are defined below in the cyclic tab for the inlet valve, exhaust valve, and cylinder region

For inlet port 1 and inlet port 2 event is defined in the permanent tab.

Physical models –

Grid control –

Base grid – dx - 0.004

dy – 0.004

dz – 0.004

Output processing Advanced parameter - Default

After the case is set up export the file to a defined folder. Run the simulation in the Cygwin. Generate the output files. As the output file is generated run the post-processing in Cygwin again. Open the output file in Preview for the mesh view and simulation

Outputs –

Mesh -

Simulation link-

https://youtu.be/rIQX1XZI6zA

Conclusion – After all the geometric correction output files are run in ParaView. For the given geometric the simulation is shown in the above link. This process is non-hydrodynamic. Piston movement is clearly visible in the animation.