6 Analysis results

Let's have a look at the results and compare the two versions.
 

In the project bar, select one analysis and naviguate through the tabs "Heat-exchangers", "Rotors", "Report-surfaces". From these tabs, we obtain the mass-flow rate through the exchanger, the thrust computed from the propeller and the flow rate through the report-surfaces.
 

 

We note that more flow comes on the lateral report surfaces (1 and 2) in the v2 at the expense of the third one. We can also note in the table of the heat-exchangers, that the estimated cooling on the radiator decreased slightly :from 0.88 kW for the v1, to 0.84 kW for the v2.
 

Let's open a split visualization to try to understand how the airflow changed.

1. Naviguate to the 'Visualisations' tab.
2. Select a 2 screen split.
3. This is a 'NS_3D projects'.
4. Select the project you created, then both runs.
5. Add a label for each run and open the visualisation.

 

• Clear or hide the fuselage parts.
• Show the wall shear stress on the engine parts.
• Rescale the color bar from 0 to 4.
• Move around to have a look at the friction in the engine compartment. You want the wall shear stress to be as high as possible for parts to be air-cooled.

Sections may also help you understand how the airflow was modified by the new ducts.
 

 

Let's check the cooling perfomance on the engine cylinders.

• Go to the 'Projects tab', and navigate the tree on the left side of the screen to select the runs.
• On the page of each run, click the 'Export details to .csv file' button. Save the files somewhere easy to access, change their name to differentiate 'v1' and 'v2'.
• Open the csv files to compare them.

This .csv contains lots of useful information about your simulation.
Naviguate to the bottom of the document and read the skin friction reports: this represent the magnitude of the airspeed in the closest proximity of the parts selected, and can give a rough idea of the cooling performance. This figure is built by making a surface integral of the wall shear stresses magnitude on the faces of the selected parts.
 

 

We find an increase of 31% and 49% in the skin friction reports on the cylinder heads. While this result is not given in kW of heat exchange, checking this levels at each design iteration, or comparing them to a reference case, can give an indication of the progress made on air-cooling.