Modelling and simulation of flow through a flowbench

Aim: To perform the flow bench analysis

Introduction & Basic Theory: A flow bench is a device used to test the internal aerodynamics quality of the engine components for a better wind flow. In this case we are going to look for the intake manifold, the valve and the chamber. The flow bench simulations help us to refine the parts design for the better performance and life to have a maximised output. Thus this setup helps in design refiremnent along with saving the time and cost of prototyping physical products.

Case setup & Explanation:

1. Firstly we will model the Chamber and than the intake manifold (In our case we are going to see the flow in both a simple manifold and a twisted manifold).
2. Than we will model the valve in the chamber.
3. Once that is done we will add lids on both the open ends so that we can grt a closed chamber for simulations.
4. Further by going the flow simulation section we will click on wizard option to set the simulation conditions and will select air as our performing gas.
5. Than we will add some boundary conditions for inlet velocity and outlet static pressure.
6. Than we will add some golas and and provide the mesh.
7. For we are going to perform the grid test we will use the three set of mesh at mesh sizes of 3, 4 & 5 and see the difference.
8. Also we will provide a local or refined mesh at around the valve to see a more refined flow of air around the valve. Here also we will use the mesh sizes of 3, 4 & 5
9. Below we can see the results obtained for the above stated setups

Results:

We have modeled two set of chamber to provide a simple flow and a twisted intake, but the straight one is just for a difference reflection and we will see the results for twisted one.

The simple or straight form can be seen below:

The velocity flow in this form can be seen below:

In this form we can see that the flow is just straight and it just falls over the valve and gets distributed in the chamber. In this fuel get mixed with the air but not to its max extent. To get the full rich mixture we need to provide a swilled flow to acheive it.

The twisted or swrilled form of intake can be seen below:

The velocity flow for this form can be seen below:

In this form we can see that as the intake is in a twisted form the air flows in a rotating form and thus enters the chambers making a swrill in the chamber leading to the mixture of air and fuel well in the chamber leading to a better cumbustion. Thus we will take this form only for our further consideration.

Now we are going to now run the grid test for mesh size of 3,4 & 5 as discussed above. We will use of velocity cut plot to see the grid test for a valve lift of 2mm.

The grid test for mesh size of 3 is as:

The grid test for mesh size of 4 is as:

The grid test for mesh size of 4 is as:

As we increase the grid size more calulation domains are created and we can see that the results are plotted in a more systamatic form.

Below we can see the flow trajectory for the velocity below for the valve lift of 0 to 8 mm.

The velocity flow for 0 mm lift i.e for closed case is as below:

As the valve is closed the flow is not shown in the chamber section.

The velocity flow for 1 mm lift i.e for closed case is as below:

Here in this case as the flow is provided and the opening is very less the air gushes into the chamber with a higher velocity due to the pressure difference which is being highlited in the diagram. In the further cases we can see as the opening increases the velocity towards the chamber will decrease.

The velocity flow for 2 mm lift i.e for closed case is as below:

The velocity flow for 3 mm lift i.e for closed case is as below:

The velocity flow for 4 mm lift i.e for closed case is as below:

The velocity flow for 5 mm lift i.e for closed case is as below:

The velocity flow for 6 mm lift i.e for closed case is as below:

The velocity flow for 7 mm lift i.e for closed case is as below:

The velocity flow for 8 mm lift i.e for closed case is as below:

Above was the velocity flows for the different valve lift.

Now we will have a look at the change in mass flow rate for the different valve lift. The below diagram will show the results.

The tabular display is as:

And the graphical representation is as:

Conclusion: From this study we can see that as the valve lift increses the velocity of the air entering the chamber decreases and the mass flow rate increases, but the difference is quit low.