Steady State Simulation of Flow over a throttle body

Objective:

• Post process the results and show pressure and velocity contours
• Show the mesh (i.e surface with edges)
• Show the plots for pressure, velocity, mass flow rate and total cell count.

1. Steady State Simulation of Flow over a body is a non-reacting simulation over a throttle body whose application is a general flow.

2. It is been carried out by Pressure based Steady Solver as throttle won't be moving.

3. Reynolds Averaged Navier-Stokes method is used to solve the compressible fluid flow inside the bent pipe and RNG-K epsilon turbulence model is chosen.

4. Cut cell cartesian method is been used along with the fix embedding in Grid controls to increase the mesh along the boundary of the throttle.

5. By trial and error method the cell counts were increased.

6. The pressure difference of 0.5 bar is kept to drive the flow from an inlet to outlet and Air is been chosen as the medium of flow.

7. Ran the simulation is Cygwin terminal.

8. Animation of Steady State Simulation flow over a throttle body:

The original profile or model after flagging:

Below is the slice of the geometry along with the Z normal with Grid Representation on the surface.

A closer look at an Embedded Mesh (Scale of Fixed Embedding in Grid Control was changed to 3 with mode 'permanent')

In terms of Velocity Magnitude without grid and surface edges. Here we can observe high-velocity magnitude affecting at the gap between the throttle and solid elbow.

The surface consists of both triangulated information and grid information, which results in weird visuals and so cell data is hidden from the multi-block Inspector. Let's take a close look at the surface

The direction of the flow field is shown below using Vectors

Views of velocity magnitude vector from different angles:

Using the glyph feature we can study the nature of flow affecting the throttle body more clearly.

When flow encounters the throttle the pressure is high and behind it creates a low-pressure region. Low pressure indicates the drop in Static Pressure.

The Stream Tracer mode of the simulation is also been created.

Total Cell count:

The total cell count remains constant with 1200 cells.

Mass Flow Rate Plots

Inlet Mass Flow Rate

Outlet Mass Flow Rate

Plots for Pressure, Velocity Magnitude, Velocity X, Velocity Y and Velocity Z against cycles

Observation:

• We can see the plots for inlet mass flow rate and outflow mass flow rate are exactly opposite symmetrical of each other with -0.063 and 0.063 respectively
• We also see the similar behaviour of Velocity Magnitude, Velocity X, Velocity Y and Velocity Z plots with 226.2m/s, 205.6m/s, -16.8m/s, -5m/s respectively as it plummets and then gets stable
• For pressure, it ends up with 104450 bar