Page 263 - Water and wastewater engineering

6-40 WATER AND WASTEWATER ENGINEERING

c. In cell [B7] write an equation to convert to m for use in the orifice equation

[B6 ] 100 mm
01. m
,
,
1 000 mm/m 1 000 mm/m
d. In cell [B8] calculate the area of an individual orifice

[B7 ] 2 (01 . ) 2
0 00785 m 2
.
4 4
e. In cell [B9] place a trial guess at the number of orifices

f. In cell [B10] calculate the flow for an individual orifice
[B4 ]

[B9 ]

g. In cell [B12] check the velocity

[B10 ]

[B8 ]
h. In cell [B14] check the headloss by solving Equation 6-18 for h
⎡ ⎛ ⎞ 2 ⎤
⎢ ⎜ [B ∗ 10] ⎟ ⎥ ∗ ⎡ 1 ⎤ ⎥
⎢
.
⎣ ⎝ ⎢ ([B 5] [B 8]) ⎠ ⎥ ⎦ ⎣19 62 ⎦ ⎦
i. In cell [B15] convert the result from [B14] to mm
]∗
[B14 1000
j. Activate the dialog box for Solver and designate the target cell [B12], that is, the one for
the velocity.
k. Set Equal to to “Max.”

l. Set By changing to the cell containing the number of orifices, that is, [B9].
m. Add the following four constraints in the dialog box:
(1) Velocity
[B12] 0.55
[B12] 0.25
(2) Headloss
[B15] 9
[B15] 3