Page History

...

Note: When you create graphs of the Nusselt number in Excel, you need to transfer the data points from the exported CSV file from ANSYS over to an Excel workbook file (.xlsx). A CSV file is just a flat text file that uses a delimiter to separate the fields (in this case, a comma). It CANNOT save any formulas or plots. A xlsx file is the typical file format for Excel, just as docx is for Word. In a xlsx file, you can save the formulas, graphs, pivots, etc in the file. It was mentioned in the video, but we wanted to emphasize.

Plotting Nux vs Pr

Here are the steps for generating a plot of Nu vs Pr for Re = 40,000.

1. For Pr=1, go to the csv file exported from CFD Post and read off the Nusselt number value for Re = 40,000. This is the Nusselt number for Pr=1 at that Reynolds number.  
2. Change Cp in Fluent 
3. Run more iterations until the you get convergence (when the residuals are below 1e-6). Note you don't need to reinitialize the guess values since the velocity and pressure fields remain the same since Cp affects only the energy equation. 
4. Export Nux vs. Rex to a csv file. Read off the Nux value for Rex = 40,000. This is Nux for the new Prandtl number. 
5. Create a list of values in Excel from these runs with the following three columns
        Cp      Pr     Nux
6. Plot Nux vs Pr and add the trend line to get a fit and the exponent m

Go to Exercises

Go to all FLUENT Learning Modules