What do pneumatic conveying and hydraulic conveying have in common?

Pneumatic conveying (PC) and hydraulic conveying (HC) have significant applications in various industries. These two methods of conveying differ only by the type of carrier fluid: one is compressible and the other is not. Nevertheless, they are considered very different, attracting different research groups that rarely have a dialog. Therefore, the main objective of this research is to compare both systems, bridge the gap, and establish common analysis principles for both PC and HC. In order to bring both these conveying methods into a common ground, a new feeder based on PC technology is designed and used in HC. Hence, similar phase diagrams are obtained. Additional windows are opened to define future research efforts to conduct PC and HC research with the same tools. In order to do this, the significance of the Archimedes number is introduced in this paper. Furthermore, non-settling flows, more common in HC, are analyzed, and detailed explanations are presented to show that they should also exist in PC, for which they have never been mentioned.