Theory
Bulk Sticking Coefficient (K
sc
) Derivation:
The Bulk Sticking Coefficient (K
sc
) is the ratio of the force necessary to initi-
ate sliding of the plate (F
s
) to the normal force on the plate (F
n
).
Where:
T
u
=
Average of readings from Torque Wrench (inch-pounds)
r
=
Radius of Plate (inches)
h
=
Height above flat surface of cake around the edge of the plate
(inches)
P
=
Cell Pressure (PSI), differential (inlet to outlet)
F
s
=
Sliding force
F
n
=
Normal force on plate
K
sc
=
Bulk Sticking Coefficient
K
st
=
Stuck Tendency Coefficient
a. The Sliding Force (F
s
):
The Sliding Force (F
s
) is a function of the measured torque (T
u
).
This equation should only be used when the radius is 1 and edge
effects are not being considered.
F
s
= 1.5 × T
u
b. The normal force (F
n
):
The Normal Force (F
n
) is determined by multiplying the area by the
differential pressure. This assumes that a pressure of 477.5 PSI
was used during the test.
F
n
= 1,500 × r
2
If you are considering edge effects:
F
n
= 1500 × (1 + 4/3h)
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