Steady State Simulation of Flow Over a Throttle body

Introduction:

To regulate the power output from an engine, there has to be some restriction of fuel - air mixture that reaches the cylinders. One way to do this is to use some kind of valve that restricts the air, fuel is then regulated to get the correct fuel – air mixture. The most common valve is of butterfly type and is used in almost every car engine manufactured today, the valve is shown in Figure.

Objective:

To simulate steady state flow over a throttle valve and post process the results using ParaView.

Geometry:

The pre-modelled throttle body was imported into Converge and the geometry was inspected for any surface errors or open edges. After fixing all the errors, the boundaries were flagged and the case was set up.

Case Setup:

The case is setup to run the simulation.

The remaining parameters are set to default.

Running The Simulation:

The simulation is run using "Cygwin"

Post-processing The Results:

Software Used : ParaView

• Mesh

• Mesh around the throttle

• Velocity Contour

• Velocity Contour around the throttle

• Pressure Contour

• Pressure Contour around the throttle

• Flow vectors around the throttle

Plotting the Results:

• Velocity Plot

• Pressure Plot

• Mass Flow Rate Plot

• Total Cell Count Plot

Discussions:

• Velocity Plot: From the above plot it is observed that the average inlet velocity and average outlet velocity reaches a steady state around 4000 cycles and since the throttle is not rotating steady state is achieved easily.
• Pressure Plot: From the above plot it is observed that the total inlet pressure of 150,000 Pa remains constant and the total outlet pressure of 100,000 Pa increases initially because of interaction with the throttle and remains constant after passing through the throttle and achieves a steady state.
• Mass Flow Rate Plot: From the aove plot it observed that after some intial cycles the mass flow rate at inlet and the mass flow rate at outlet remains constant and achieves a steady state as it obeys the Law of Conservation.
• Total Cell Count Plot: From the above plot it is observed that the total numbers of cells are 41,454 cells.

Steady State Simulation of Flow over a throttle body can be visualized from the animation below

Streamline Flow

Conclusion:

Steady state simulation of flow over a throttle body helps us to get an overview of how the flow profile varies over the given case. We learnt how to do the case setup process for the given problem and how to run the simulation using Cygwin64 Terminal (in both serial and parallel processing). The method of post processing the results is done using ParaView5.4.1 and the different contours are plotted to analyze the case.