To further study the rheological characteristics of high-solid sewage sludge
revised Herschel-Bulkley model was selected according to total solid(r
TS
)of sludge to simulate flow behavior within digesters reasonably. The effects of sludge type
total solid
the range of shear rate
temperature on the critical shear stress in the flow curve were investigated in the experiments. Anaerobic digested sludge with total solid of 5.2%-15.8% was sheared by employing shear rate sweep ranging from 0.01 s
-1
to 1 000 s
-1
for steady rheological tests. The results indicate that for the sludge with r
TS
<
8.8%
the flow curve is well fitted
by Herschel-Bulkley model. While for the sludge with r
TS
>8.8%
a critical shear stress appears in the flow curve within the range of 1-10 s
-1
and the flow curve is fitted by the revised Herschel-Bulkley model. The critical shear stress is correlated to the total solid and the range of applied shear rate
but not to sludge type
composition
tested temperature or digestion time. The critical shear rate (?overγ)
c
corresponding to the critical shear stress shows a linear relationship with r
TS
of digested sludge.
关键词
Keywords
references
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