Flow simulation inside a flowbench valve geometry in Solidworks

Aim:

To model and simulate flow through a flowbench valve geometry in Solidworks.

Objective:

• To conduct grid dependency test to select optimum mesh settings.
• To simulate the flow inside a flowbench geometry.
• To compare the mass flow rate for different valve lifts.

Theory:

An air flow bench is a device used for testing the internal aerodynamic qualities of an engine component and is related to the more familiar wind tunnel.

It is used primarily for testing the intake and exhaust ports of cylinder heads of internal combustion engines. It is also used to test the flow capabilities of any component such as air filters, carburettors, manifolds or any other part that is required to flow gas. A flow bench is one of the primary tools of high-performance engine builders, and porting cylinder heads would be strictly hit or miss without it.

Setup Explanation:

1. First, the flowbench geometry is modelled using appropriate dimensions. As shown.

2. The valve sketch is fully defined such that the valve lift can be varied by changing the dimensions.

3. Add lids to the inlet and outlet ports to make the geometry watertight.
4. Then, under flow simulation option click on wizard tool and create a new setup with default options, internal flow study with air as the working fluid.
5. Keep the mesh setting to 5.
6. Insert a boundary condition at inlet with total pressure as 101325 Pa as shown.

7. Insert a boundary condition at outlet with static pressure as 51325 Pa as shown.

8. Insert a surface goal of mass flow rate on outlet lid 2.
9. Insert a velocity cut plot in the centre front view.
10. Insert a surface parameter for mass flow rate at outlet.
11. Insert a flow trajectory from input face to output face with 100 pipes in between.
12. Do the above processes for mesh setting as 6 and 7 as well to determine the most accurate setting.
13. After determining the best mesh setting, run a parametric study with the valve dimension as the input variable varying from 1 to 5 mm with a total of 5 values.
14. Set the goals, cut plots and flow trajectories as output parameters and run the study.

Results:

Study 1: Grid dependency

• The model is evaluated at 1 mm valve lift for mesh settings of 5, 6 and 7.
• The following plots are obtained.

• As can be seen, with mesh setting of 7, the plot is more accurate and vivid. Also, the value of mass flow rate is changing significantly with every mesh setting indicating that mesh setting of 7 is most accurate and we hence we choose this setting.

Study 2: Parametric Study

• At 1 mm:

• At 2 mm:

• At 3 mm:

• At 4 mm:

• At 5 mm:

• Variation of mass flow rate with lift:

Conclusions:

1. From the velocity plot, we conclude that as the valve lift increases, the inlet velocity increases.
2. From the goal plots, we conclude that as the valve lift increases, the mass flow rate also increases but with decreasing slope. This indicates that after a point the valve lift wont have any effect on the mass flow rate.

File Link:

https://drive.google.com/drive/folders/1t8KIXi2gQFncMmRgp8XsB2AVt4QnsJtC?usp=sharing