Static flowing solids, flow pattern

The mixing and flow patterns of gravitational dry particulate flows in continuous mixer tubes with helical, Kenics-type [1] static mixer elements have been simulated by the distinct element method (DEM) under steady state conditions. In the particular system the subsequent mixer elements were twisted in opposite direction a mixing element twisted clockwise is followed by an element twisted counter-clockwise and so on. A state diagram that gives a general relationship between the mass flow rate and the solids volume fraction in the mixer tube was determined for various construction parameters. 

Patterns of gas-solid interaction in dryers (a) gas flow across a static bed of solids (6) gas passing through a bed of preformed solids (c) showering action in a rotary dryer d) fluidized solids bed (e) cocurrent gas-solid flow in a pneumatic-conveyor flash dryer. 

The static mixer tubes containing one or more motionless mixer elements can modify the hydrodynamic patterns of flowing systems in an effective way. The mixing effect arises from the complex and multiple interactions between the mixer elements and the phase elements in their vicinity. Analysis of the flow and mixing behaviour of solid particles in these systems is an important topic in terms of equipment design and construction for processing particulate solids. 

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