I use ANSYS, for CFD of industrial combustion systems, all the time. It took me a long time to get something even remotely close to what I theorised the internal environment of a suppressor to be. And I've been making suppressors for around a decade. Impulse flows are unpredictable and the specific media of these fluids is not easily modeled. Results can be wildly inconsistent and I have no way to correlate them with dB reduction. Yes, you can record exit pressure and velocity, but, again, I have no access to metering equipment.
This being said, I have found constant flow modeling of specific features or singular designs to be helpful. They seem to match with proven designs.
As I said above, the NFA forums are an unprecedented wealth of information. Without them, you'd be where Maxim was, at the turn of the century.