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

Objective: To perform surface preparation and boundary flagging tasks on our IC Engine case and set up a No Hydro simulation.

Procedure:

The PFI geometry .stl file is imported in the Converge Studio. The base geometry has surface errors that need to be cleared before we move up with the simulation.

Geometry:

Simulation error (before case setup):

Boundary Flagging:

To flag the boundaries, we need to create fences across the edges of separating boundaries so it eases the selection of boundaries.

Liner: 

Two edges were selected to mark the fence across the Liner edges and the boundary is flagged using the boundary fence method as shown below.

Piston:

The piston is flagged by the boundary fence method as shown below. 

Cylinder Head:

Boundary fences are created along the 4 edges which separate the region of the ports & spark plug from the cylinder head region and the cylinder head is extracted as shown below. 

Intake Port:

The intake port is split into two boundaries & later into two regions to separate the boundaries for different initial and boundary conditions. The intake port is where fuel spray and the air is injected. A fence is created using a fence between vertices and appropriate boundaries are flagged from the boundary fence method. 

Exhaust Port:

The outflow is flagged using the boundary fence method and the rest of the region as outflow as shown below.

Valves:

Intake & Exhaust ports, Liner, and cylinder head are hidden and then valves are visible. The valve geometry is flagged into 3 boundaries. This is done to create the events and ease the creation of disconnect triangles and assign realistic boundary conditions. Also, a translatory motion is provided to these valves by loading the motion files. 

Spark Plug & Terminal:

The region where the spark is generated is at a higher temperature than the rest of the spark plug. Hence, two boundaries are necessary to assign appropriate conditions. 

Top of Valve top assigned to port boundaries:

Due to the translatory motion of the valves and as it is connected to ports, during movement the surface of the ports gets distorted. To avoid this distortion, the top of the top valves is assigned to the port boundary as shown below.

Flagged boundaries:

Surface Preparation:

Regions:

Regions are created which are used to create events between the zones and to initialize the realistic initial conditions in the flow domain. 

Initial and Boundary Conditions:

Boundary Conditions:

Regions:

Events:

Mesh Size:

Here the base grid of 0.004m is used along with the fixed embedding. For the Intake and Exhaust valve angle scales of 3 and 1 embedding layer is used with Permanent Mode. Whereas, for the Cylinder region and zones next to the valves in the ports a cylinder entity is used with a scale of 2 & 1, respectively. 

Results:

The results are processed for No-Hydro simulation and the grid size is coarsened by a factor of 4 (n = -2) as the computation time was too high for the fine mesh. The grid was coarsened as it was only a no-hydro simulation. The simulation took  263 sec while running with 6 processors.