Inlet Channel Design Program
The purpose of this program is to determine the dimensions of the inlet channel as well as the dimensions of the hole and the chimney that deliver water from the inlet channel into the sedimentation tank. The inlet channel will run along the inlet end of the sedimentation tanks, such that its length will be equal to the combined widths of all the sedimentation tanks plus the thickness of the walls between the tanks and the thickness of the walls that separate the bays within the sedimentation tank channels. The dimensions of the width and depth of the channel depend on the water level in the sedtank, which should be about the same as in the channel and the flocculator, and the length of the flocculator, since water runs from the end of the flocculator through the channel.
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[!chimneypic1.PNG|width=500px!]
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[!Chimneypicright.PNG|width=500px!]
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[!Chimneypicfront.PNG|width=500px!]
Inlet Channel Design Algorithm
Algorithm
The primary constraint for designing the channel connecting flocculation and sedimentation tanks is the depth of the channel. The channel must be designed to make sure that the transition between the two tanks does not break up the flocs formed in the flocculation tank.
The length of the channel is a function of the number of sedimentation tanks, and the thickness of the walls between the sedimentation tanks.
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\large
$$
L_
Unknown macro: {Channel}
= (N_
Unknown macro: {SedTanks}
)(W_
Unknown macro: {Sed}
) + (N_
+ 1)(T_
Unknown macro: {PlantWall}
)
$$
The cross sectional area of the inlet channel is determined using the A.Port function in Fluids Functions
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\large
$$
A_
Unknown macro: {InletChannel}
= A_
Unknown macro: {Port}
(Pi_
Unknown macro: {FlocDissipation}
,K_
Unknown macro: {LTurn90}
,Q_
Unknown macro: {Plant}
,ED_
Unknown macro: {SedInlet}
,Pi_
Unknown macro: {VenaContractaOrifice}
)
$$
Therefore the height of the water in the inlet channel is equal to the squareroot of the area of the channel.
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\large
$$
HW_
Unknown macro: {InletChannel}
= \sqrt {A_
}
$$
The minimum width of the inlet channel in consideration of the energy dissipation rate is equal to the area of the inlet channel divided by the height of the water in the inlet channel
Unknown macro: {latex}
\large
$$
W_
Unknown macro: {InletChannelED}
= {{A_
Unknown macro: {InletChannel}
} \over {HW_
}}
$$
Next the size of the channels that take the flocculated water down into the sedimentation slopes is calculated through the A.Port function in Fluids Functions.
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\large
$$
A_
Unknown macro: {SedManifoldEntrance}
= A_
Unknown macro: {Port}
(Pi_
Unknown macro: {FlocDissipation}
,K_
Unknown macro: {PipeEnt}
,Q_
Unknown macro: {SedManifold}
,ED_
Unknown macro: {SedInlet}
,Pi_
Unknown macro: {VenaContractaOrifice}
)
$$
The diameter of the hole that delivers the water froom the inlet channel into the inlet chimneys is calculated using an array that loops through the available pipe size diameters and round the needed diameter up to the next available diameterthrough the function found in the Pipe Database.
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\large
$$
{D_{SedChimneyPipe}} = {D_{pipelarger}}\left( {2\sqrt {{{{A_
Unknown macro: {SedManifoldEntrance}
}} \over \pi }} ,\left. {{D_
Unknown macro: {Pipesizes}
}} \right)} \right.
$$
Because the circular hole through the inlet chimneys must have at least 3 cm of space around it, the width of the inlet channel is set to be the maximum of the width determiend by the allowable energy dissipation in the inlet channel, and the width needed by the circular hole in the inlet chimney.
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\large
$$
{W_{InletChannel}} = \max \left( W_{InletChannelED,\left. D_{SedChimneyPipe + 2{S_
Unknown macro: {SedInletChannelMin}
}} \right)} \right.
$$
The height of the inlet channel is equal to the water height in the inlet channel plus the plant freeboard height, so that the water is not at the very top of the channel.
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\large
$$
H_
Unknown macro: {InletChannel}
= HW_
+ H_
Unknown macro: {PlantFreeboard}
$$