Steady state simulation for flow over a throttle body

Objectives of the Project:

(1) Perform a steady state simulation for the flow of air over a throttle body in Converge Studio and post-process the results in ParaView.

(2) Show the plots for pressure, velocity, and mass flow rate.

Geometry:

The throttle inside the pipe is aligned parallel to the plane of the pipe. The red face is inlet and green is the outlet.

Mesh:

Base Mesh

• along x-direction = 0.002 m
• along y-direction = 0.002 m
• along z-direction = 0.002 m

Fixed embedding option is enabled at the walls of the pipe and at the throttle valve.

At Throttle valve

• Scale = 2
• Embedded layers = 3

At Pipe wall

• Scale = 1
• Embedded layers = 2

Initial and Boundary Conditions:

• Inlet Pressure = 150000 Pa
• Outlet Pressure = 101325 Pa
• Law of Wall at Pipe wall and on Throttle surface

The simulation was run for a total of 15000 cycles, but the steady state was obtained much before. Hence it ran for a total of 9363 cycles.

RESULTS:

Total Cells during the simulation is constant as Adaptive mesh refinement is not enabled.

Mass flow rate at the inlet

Mass flow rate at the outlet

Average velocity at the inlet

Average velocity at the outlet

Velocity contours

Pressure contours

Velocity and Pressure on the throttle valve surface

Glyph Plot shows the direction of flow in the pipe

Stream Lines

Conclusion:

• The plots for mass flow rate and average velocity shows the convergence of simulation.
• A maximum velocity of about 310 m/s is observed adjacent to the throttle valve. This is because the area is decreased suddenly and after passing through the narrow passage we see a decrease in velocity.
• Pressure variation can be seen from the pressure contour. There is a pressure drop across the throttle valve. Due to the obstruction, pressure increases before the throttle valve.
• The velocity streamlines show that velocity of air increases as it flows over the throttle valve.