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Experiment
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2:
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February
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28, 2010
Setup
This experiment consisted of one 10' Manifold with 1 in. holes drilled every 5 cm on one side of the pipe. This resulted in an Am/Avc = 1.
Results & Discussion
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2010 h2. Setup This experiment consisted of one 10' Manifold with 1 in. holes drilled every 5 cm on one side of the pipe. This resulted in an Am/Avenacontracta = 1. h2. Results {float} !10'ManifoldResults.png|width=450px! h5. Figure 1: 10' Manifold Results compared with theoretical expectations {float} |
The
...
results
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of
...
our
...
second
...
experiment
...
seem
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to
...
reaffirm
...
the
...
results
...
that
...
we
...
found
...
in
...
the
...
first
...
experiment,
...
despite
...
the
...
problems
...
with
...
data
...
collection
...
that
...
existed
...
in
...
the
...
first
...
experiment.
...
The
...
flow
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starts
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low
...
then
...
peaks
...
in
...
the
...
first
...
quarter
...
of
...
our
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manifold
...
and
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then
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gradually
...
decreases
...
after
...
that.
...
And
...
as
...
showed
...
in
...
the
...
graph,
...
this
...
is
...
completely
...
opposite
...
what
...
the
...
theory
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of
...
pressure
...
recovery
...
predicts.
...
The
...
good
...
news
...
with
...
these
...
results
...
is
...
that
...
the
...
flow
...
from
...
the
...
ports
...
might
...
be
...
sufficiently
...
uniform
...
for
...
it
...
to
...
work
...
in
...
the
...
AguaClara
...
plants.
...
The
...
mean
...
velocity
...
is
...
0.214
...
m/s
...
and
...
has
...
a
...
standard
...
deviation
...
of
...
0.021
...
m/s,
...
which
...
might
...
be
...
low
...
enough
...
variation
...
for
...
the
...
AguaClara
...
plants.
...
The
...
mean
...
velocity
...
might
...
be
...
a
...
little
...
high
...
when
...
considering
...
the
...
restriction
...
of
...
floc
...
breakup
...
prevention as
...
there
...
is
...
an
...
average
...
energy
...
dissipation
...
rate
...
of
...
19
...
mW/kg
...
when
...
the
...
max
...
allowable
...
to
...
maintain
...
flocs
...
is
...
10
...
mW/kg.
...
This was determined by using the equation
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$$
\varepsilon _{Max} = {1 \over {20D_{Port} }}\left( {{{V_{Port} } \over {K_{vc} }}} \right)^3 $$ |
We estimated the flow rate being provided by the pump to be 3.8 L/s. This value was calculated using the following equation:
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$$
Q_{Manifold} = [\sum {(V_{Measured} \cdot A_{SedPort} } \cdot Pi_{vc} )] \cdot {{N_{portsTotal} } \over {N_{portsMeasured} }}
$$
|
This finds the average port flow of the measured ports and then multiplies it by the total number of ports. Given this flow rate, the velocity inside the manifold would be 0.21 m/s at the beginning of the manifold. This meets the specification of
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$${V_{Scour}}$$ |
We still do not understand the fluid mechanics of what is happening in the manifold and need to investigate that further. We plan on doing this by pushing the boundary of the ratio Am/Avc. Theory says that the smaller that ratio gets, the more pressure recovery should dominate and the higher velocity should be at the end of the manifold compared with the beginning of the manifold as illustrated in Figure 1 on the main page.
To see the calculations for the experiment, use the MathCad Calculations and the Excel Calculations.