Steady state simulation of flow over a throttle body in CONVERGE CFD

Aim:

To simulate steady state flow over Throttle body.

Problem Discription:

Geometry:

Geometry of elbow pipe with throttle valve fitted inside is created in solidworks and then it is imported as .STL file in CONVERGE studio.

Here,in this problem we are not performing heat transfer analysis so thickness and outer boundary is removed as part of geometry cleaning.

Material: Air

Initial Condition:

Preasure : 101325 Pa

Temperature : 300 k

Boundary Condition:

1.Inlet

Type: INFLOW

pressure: 1.5e5 Pa (Total Preassure)

2.Outlet

Type: OUTFLOW

pressure: 1e5 Pa (Static Preassure)

3. Elbow Wall

Type : Wall

4.Throttle Body

Type :wall

Run Parameters:

Solver: Preasure based steady state solver.

Simulation Time Parameters:

The simulation is run for 15000 cycle but we have enabled the steady state monitor.Hence the simulation will stop when variation is within tolerance.

Turbulence Modeling:

Turbulence Model: RNG k-ϵ

Mesh Size:

Mesh size is 2e-3 in X,Y & Z direction

Fixed Embedding:

This feature helps to refine grain size in particular area.

Boundary ID: Throttle Body

scale: 3

Embed layer : 2

Result:

Mesh:

Grain refinement near Throttle body after fixed embedding

Mass flow Rate:

Average Velocity:

Total Preassure:

Static Preassure:

Total cell count:

Velocity Contour:

Preassure Contour:

Conclusion:

1.Total cell count for mesh size 2e-3 is ~35500.

2.Throttle body is not sealing elbow completely hence fluid leakage is observed.

3.Hence,Total Preassure increases at outlet but Static preassure decreases.