HYDRAULIC ANALYSIS CALCULATION FOR ASH SLURRY PIPELINE
The
velocity of slurry in pipelines shall be in the range 1.8 m/s to 2.5m/s to
avoid increasing the wear rate of the pipeline (if operating velocity above
2.5m/s) and risks of settling out and causing a blockage inside pipeline (if
operating velocity below 1.8m/s). This slurry is non-Newtonian fluid so that
the formula of Durand equation will be applied to calculate the friction loss
of slurry.
The
difference i - iw
represents an increase in pressure drop due to the presence of solids in the
slurry. The effect of particle size on slurry pressure drop is accounted for by
the inclusion of the drag coefficient CD.
In most
industrial applications, the particle size is not uniform, so the equation
above can be written as follows:
Step 1: Calculation CDRew2
based on input data.
CDRew2
= ρl(4gd3(ρs - ρl)/(3µ2gc2
Whereas:
CD – Drag
coefficient
d – Particle diameter
(m)
g – Acceleration due
to gravity (9.81 m/s2)
ρl –
Density of liquid (kg/m3)
ρs –
Density of solid particle (kg/m3)
Rew = d ρl
w0/(gµ)
w0 –
settling velocity (m/s)
µ - viscosity of
liquid (kg.s/m).
Step 2: Find the drag coefficient of
particles of individual size fraction based on result of step 1
Source: Piping handbook, seventh edition.
Step 3: Calculation
of friction loss of slurry
Calculation
follows below equation:
iw
– friction loss for water (mH2O/m) were calculated by software.
i
– Friction loss for slurry
Cvi
– volume fraction of solid having size di
CDi
– Drag coefficient of particle having size di
N –
Total number of size fraction into which given particle size distribution is
divided.
Calculation file: Download
