Project Transient simulation of flow over a throttle body

Abstract
In this project, a flow inside a curve pipe with rotating throttle inside was simulated using CONVERGE Studio and view the results of the simulation. After the simulation, the project was post-processed in ParaView to understand the results visually. Visualization was taken from ParaView and Plots were made in Converge Studio.

Introduction
The purpose of this simulation was to simulation the flow inside a elbow pipe and see the flow behavior of rotating throttle inside the elbow pipe.

Methods
The elbow pipe with the throttle inside file in stereolithography (.stl) format was provided as shown in Figure 1.

FIGURE 1 Geometry view of the elbow pipe with the throttle in Paraview.

Case Set-up
Case was set-up as previous simulations, https://bit.ly/2RZQrlt, however, for the throttle boundary condition, Rotation Rate file was provided with the following rate

• 0.000 seconds Angle: 0.00
• 0.002 seconds Angle: 25.00
• 0.004 seconds Angle: 25.00
• 0.008 seconds Angle: 0.00

and Rotation center and Rotation about was measured using Arc normal Direction tool under Measure. Since this is transient part of the simulation, the end time was 0.01 (10ms), and turbulance modeling was turn on.

Results and Discussion

FIGURE 1 Velocity contour at 2 milisecond.

FIGURE 2 Velocity contour at 10 milisecond.

FIGURE 3 Pressure contour at 2 milisecond.

FIGURE 4 Pressure contour at 10 milisecond.

Figure 1 through 4 shows the velocity and pressure contour at different milisecond. As seen from the figures, there is a high pressure region at 2ms due to rotation of the throttle. The throttle has rotated 25 degree, blocking the path of the flow, thus creating high pressure - low velocity region. However, after 4ms, the value began to rotate back to its original angle (0.00), thus the air flows easily at higher velocity.

FIGURE 5 Velocity Plot.

FIGURE 6 Pressure Plot.

FIGURE 7 Mass Flow Rate Plot.

FIGURE 8 Total Cell Count Plot.

FIGURE 9 Mesh view of the geometry.

FIGURE 10 Mesh view of the geometry near the throttle at time = 2ms.

Below are the screenshot of velocity streamline in Paraview.

Conclusion
In conclusion, the simulation ran successfully showing the transient simulation of the flow behavior over a rotating throttle. It was observe that transient simulation takes longer than steady-state simulation because results didn\'t converge until the end of simulation time, as seen in Figures 5 through 10. Stream tracker was used to visualize the flow stream at different time step.