It is expected to be able to measure powders~~~~ properties such as, flowability, wall friction
and bulk density, etc.
Shear cell technology provides the solution through the use of an annular shear cell and a wall friction
Evaluation of the wall friction
coefficient for a sinusoidal corrugated wall is determined as:
The FT4 Powder Rheometer offers dynamic, bulk, and shear property testing capabilities and incorporates well-defined methodologies and software for the measurement and interpretation of wall friction
This article focuses on the known complications associated with uniaxial compression of powders in a cylinder due to sample-wall friction
, and presents an instrument configuration and analysis technique that isolates effects of wall friction
However, with the roughness reduced on the inner wall, the small convex parts are all completely submerged in the viscous sublayer and the gas pipeline becomes "hydraulic smooth pipe" That means even though the coating surface is smoothed further, the wall friction
is difficult to further reduce.
This approach creates high wall friction
, which generates fine resin dust that carries static charge, making it stick to pellets and silo walls and roofs, causing periodic "dust surges.
The Brookfield Powder Flow Tester features a variety of test options including: flow function, time consolidation, wall friction
and bulk density.
During the expansion phase, reverse squish as the flow exits from the piston bowl and wall friction
contribute to the sudden fall of the swirl velocity.
They are as follows: shock loss at an inducer inlet, wall friction
loss within impeller channels, tip leakage loss, secondary flow losses, mixing loss at diffuser inlet, wall friction
loss within a diffuser, sudden expansion loss at a scroll inlet, wall friction
loss within a scroll.
These are generally aimed at reducing wall friction
to allow the material to slip more easily; but, in some cases, high friction is employed to resist slip in selected regions of the hopper walls.
A-2000, with its inner wall formed over a polished mandrel, has a low wall friction