Assignment 11

Step 1: Select the Single cyl DI tutorial.

Step 2: Make the discretization length as a parameter.

Case Setup:

Here two cases are taken. One of which has discretization length as 40mm while the other has 0.1mm.

Post-Processing:

As we can see here, the difference in the result of both cases is not quite big.

Brake Torque: case1: 96.2 N-m while in case 2: 95.9 N-m that is the total deviation is 0.3 N-m. Similarly, deviation in the BSFC is 0.7 g/kW-hr.

The difference in the in-cylinder pressure is 1.93 bar.

it is seen here that the difference in the total time is quite drastic. As compared to the other quantities, the time difference is quite large. So it is unnecessary to use the small value like 0.1mm as discretization length. The result obtained by the 40mm discretization length is enough and appropriate.

Q2. Explore tutorial no 2 (GEM3D) - “Building intake manifold from STL model”.

Ans: 

First the .stl file is imported to the GEM3D.

The imported model/ design is shown below:

The above shown image is of Intake Manifold without discretization.

The next step is to Separate the design according to the curve. In this step, all those parts are discretized which have sudden changes in the dimensions. 

The different color shows the different parts which are distributed by the GEM3D.

Now using the 3-point cutting plane tool, different sections are formed.

After using the cutting plane:

After getting the sections, they can be represented by pipe or flowsplits. this is done with the help of convert mesh operation.

After that, the next step is to make an orifice connection to reduce the losses due to sudden changes in the shape. 

Here the Forward Discharge Coefficient is turned into the parameter and also the object name is given.

The value of the Forward Discharge Coefficient is fed into the Case setup as 0.9.

Now after that, the input and outputs of the design are defined for the GT Power.

Now the rest of the entrance part can be cut into sections of pipes and flowsplits.

After the final section:

After this, the gaps between the pipes have to be filled using flow connection.

All the flow connections and extruded connections are made and the final model is now ready to get converted into a 1-D model.

Discretizing the model:

Here we can see that the discretization length is taken as 40 as default. 

Final Discretized model in 1-D:

Hence the Example has been explored and understood properly.