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Table 1 The calculation of the apparent viscosity η S and the shear rate γ ˙ [17],[18]

From: Floating layer formation, foaming, and microbial community structure change in full-scale biogas plant due to disruption of mixing and substrate overloading

Measuring system

Equation

Constant

Double gab measuring system

τ = 1 + δ 2 ( δ 2 · R 3 2 + R 2 2 ) · M 4000 · πL C L

C L = 1.10

δ = 1.0245

RMKi = 20.25 mm

γ ˙ = ω · 1 + δ 2 δ 2 - 1

RMKa = 21.00 mm

L = 78.7 mm

Cylinder measuring system

τ = 1 + δ 2 2000 · δ 2 · M 2 π L · R i 2 · C L

C L = 1.10

δ = 1.0848

γ ˙ = ω · 1 + δ 2 δ 2 - 1

RMKi = 13.33

L = 40.003 mm

Ball measuring cell

τ = C ss ·M

C SS = 15.0 Pa mNm

C SR = 0.427 min s

γ ˙ = C SR · n

d K = 12.0 mm

Paddle mixer [17]

Ne = P p · n 3 · d 5 = C lam Re C turb

CMO = 10.94

Clam = 189.6

Cturb = 9.4

γ ˙ = C MO · n

d R = 30 mm

d B = 143 mm

Pipe viscosimeter [18]

τ w = d · p 4 · L

Lpipe = 2,500 mm

dpipe = 43.2

dw dr w = 3 n ' + 1 4 n ' · 8 · w m d

n ' = dln d · p 4 · L dln 8 · w m d