Improving indirect heat transfer to solids by better mixing
This review of literature citations relates how mixing affects the heat transfer rates to solids in a variety of processing units. These units will include pan, horizontal (rotary vacuum), screw conveyor and paddle dryers and/or processors.
The data presented will show that, in all cases, the investigators found that by increasing the speed of mixing the heat transfer rate is enhanced except when the agitator speed produces mechanical fluidization and/or during the constant rate period of a drying cycle.
Some recent work in the area of the paddle processor design will be reported. It shows that agitator shape and the density of the heat transfer surface to process volume improves the heat transfer rate along with the speed of rotation of the processor’s agitator.