Brookfield DV3T - Page 83

Brookeld Engineering Labs., Inc. Page 83 Manual No. M13-167-A0415
yielding,theproductcreatesaowcurveandbehavesasaPowerLawuidsothatnindicates
wherethereisashear-thinningorshear-thickeningtendency.(Inthiscase,ifn=1,thematerial
isbehavingasaBinghamuid,whichisdiscussednext.)
An Example of the Herschel-Bulkley Model at Work
A company uses a gel-like substance as part
of their production process. Upon arrival
they test the material and apply the Herschel-
Bulkley model to ensure it will perform
correctly during process. The results in Figure
VII-2 show that the consistency index is 8,550
cP, the ow index is 0.66, and the yield stress
is 51.0 dynes/cm
2
. These results indicate that
this batch of gel does not quite meet specication. While the consistency index is within
spec, the yield value is higher than normal so the uid will not begin to ow as easily. With
a ow index of 0.66, this batch is also less shear thinning than normal. Pump and mixer
speeds must be adjusted before using this material.
Gel-Like Substance
n = 0.66
τ
o
= 51.0 dynes/cm
2
k = 8550 cP