Cgns
 

I am using CFX for transient simulation and want to get the data of the flow rate at the outlet interface over time. However, only CGND can be exported under the export function.
May I ask which software can be used to open this format file? Can I get the text file? Can I use Excel to open it

CGNS is an open CFD standard. Many packages can open it - theoretically. In my experience I have never got it to work for me and I use other formats to transfer between packages.

The easiest way to get a text file of your solution is to open the results file in CFD-Post and go File/Export, select the domain(s) covering the solution and the variables you want to generate. But be warned - even a very small CFD simulation will generate huge files using this method. So big you will probably fill your hard drive and/or crash CFD-Post or Excel.

To keep it manageable you will have to select a few points of small regions to export. Then just select the objects you want to export in file/export.