 |
||
|
|
||
| |||||||||||||||
|
|
 ERDC TN-DOER-I3
July 2000
This represents the overall slurry density transported to disposal. It is a function of suction line
head losses, cutface height, and cycle efficiency.
The cycle efficiency is defined as the ratio of the average solids component of the slurry over the
entire cycle to the average solids component of the slurry when the dredge is engaging the material.
This efficiency is computed as:
ρcyc - 1
Ceff =
(3)
ρmat - 1
The cycle efficiency can also be presented in terms of time as:
T
Ceff = sol
(4)
Ttot
where
Tsol = the time pumping solids
Ttot
= the total time (time in solids and water)
The production rate for the dredge is calculated by the following equation:
aV f Ap
ρcyc - ρw
PRO =
(5)
ρi - ρw
where
= production rate in m3/hr
PRO
ρw
= the water density in g/cm3
ρi
= the in situ sediment density in g/cm3
V
= the slurry velocity in m/hr
= the discharge pipe area in m2
Ap
The density and velocity data can be acquired with a laptop computer and be summarized and
displayed over any time interval or in any format. Graphical and tabular summaries of variations
in the average slurry density transported can indicate problems with changing site conditions such
as sediment composition or size, variation in cutface height, obstructions in the channel, and
increased digging depth. If the dredge is configured to operate in a fine sand, and coarse sand
deposits are encountered, the increased suction and discharge line losses can be greater than the
pump capability, thus significantly impacting production and efficiency. Variation in cutface height
has a significant impact on production. Areas where the cutface height is minimal will have a
decreased production rate. Obstructions in the channel or difficulties in dredging sediments more
5
|
|
Privacy Statement - Press Release - Copyright Information. - Contact Us - Support Integrated Publishing |
