Week-11 : Discretization of 3D intake manifold using GEM-3D

Assignment 11: Discretization

Aim:

To study discretization using GEM3D software

Introduction:

In this assignment, we will be focussing on the topic of discretization. We will study the effects of varying the length of discretization as well as will be converting a 3D model to GT components. Given the two different topics, this assignment is divided into two parts/ questions.

Question 1

For this question, we need to study the effect that varying the discretization length has on certain parameters. For this purpose, we are considering the model shown in Fig_1

The discretization length used in the default model is 40 mm as shown in the Fig_2. We will now create a parameter for the discretization length and will add another case as shown in Fig_3 for the new length given. Now we run the model.

We will now discuss the differences based on the following parameters.

• Simulation time. For the default case, the simulation was completed in a few seconds, while for the modified case around 10 mins were required.
• Torque: As far as torque is concerned, there is not much of a difference in both the cases, as seen in Fig_4
• BSFC: As seen in Fig_5, there is not much of a difference in the predicted values in both the cases
• Max Pressure: As seen in Fig_6, a small difference of 2 bar can be seen in the predicted values.

So overall, there is not much of a difference in the values that are predicted by both the discretization lengths.

Question 2:

In this case, we need to explore the tutorial 2 of the GEM3D intake manifold example. Refer Fig_7 for the same.

In this model as we see, we have a intake manifold system which we explored previously in the videos as well. This model has already been cut into different pieces for us and only some further changes are to be done. Here is a list how the parts have been cut:

• Intake runner: Each runner has been cut into 3 parts, one part for pipe bend, while the other two for straight pipes, thus modelling each features of the manifold
• The intake pipe is divided into 3 parts as was seen in the video
• The same is applicable to the plenum, which is also divided into parts and modelled as flowsplit.

The only remaining this is that the flow connections have not been made. This can be easily understood when we look at Fig_8. We will now complete those connections. The modelled has been properly developed as can be seen in Fig_9. We will now convert the same to a GT power model. The same can be seen in Fig_10.

Thus we have completed all the required tasks.