Saltation pneumatic transport

One major difference between pneumatic transport and hydraulic transport is that the gas-solid interaction for pneumatic transport is generally much smaller than the particle-particle and particle-wall interaction. There are two primary modes of pneumatic transport dense phase and dilute phase. In the former, the transport occurs below the saltation velocity (which is roughly equivalent to the minimum deposit velocity) in plug flow, dune flow, or sliding bed flow. Dilute phase transport occurs above the saltation velocity in suspended flow. The saltation velocity is not the same as the entrainment or pickup velocity, however, which is approximately 50% greater than the saltation velocity. The pressure gradient-velocity relationship is similar to the one for hydraulic transport, as shown in... 

Cabrejos, F. J., and Klinzing, G. E., Minimum Conveying Velocity in Horizontal Pneumatic Transport and the Pickup and Saltation Mechanisms of Solid Particles, Bulk Solids Handling, 14(3) 541-550 (1994)... 

Cabrejos, R J. and Klinzing, G. E. 1994. Minimum conveying velocity in horizontal pneumatic transport and the pickup and saltation mechanisms of solid particles. Bulk Solids Handling 14 541-550. 

In the region E and F some solids may move in dense phase flow along the bottom of the pipe whilst others travel in dilute phase flow in the gas in the upper part of the pipe. The saltation velocity marks the boundary between dilute phase flow and dense phase flow in horizontal pneumatic transport. 

In horizontal pneumatic transport of particulate solids, what is meant by the term saltation velocity ... 

Cabrejos FJ, Klinzing GE. Pickup and saltation mechanisms of solid particles in horizontal pneumatic transport. Powder Tech 79 173-186, 1994. 

H.S. Muralidhara, W.J. Rebello, R.P. Kiishnan and C.Y. Wen, Saltation velocity correlations for the design of long-distance horizontal pneumatic coal transport systems, Int. Powder Bulk Solids Handling Processing, Huladelphia, 1979. 

The first section was a 238 m horizontal pipeline from the ice plant to the top of the vertical mineshaft, within which pneumatic conveying was employed to transport the ice. Depending on the superficial air velocity, the flow could be Mly suspended dilute-phase (above 40 m/s) stratified dilute-phase (30-40 m/s) sliding clusters (27-30 m/s) or plug flow with nearly fiill-bore plugs (20-27 m/s). Similar successive flow regimes have been described frequently for a variety of conveyed materials [e.g. 6,7]. In this case the saltation point... 

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