What is a compatible part that I can buy from Digikey?

The other marking on the part is Crouzet 70546294


That looks to be a 92mm square x 25mm 120VAC unit with wire leads giving high-30s CFM and a bit under 0.2" static pressure. These look to be in-stock options matching that general description.

This post offers further information on fan selection topics, if you’re interested.

As per our product manager for Crouzet, these fans are obsolete and originally were sourced from Sunon