Page 89 - ebook fluid mechanics_finalize

FLUID MECHANICS

Example 4.10

A horizontal venturi meter measures the flow of oil of specific gravity 0.9 in a 75 mm

diameter pipe line. If the difference of pressure between the full bore and the throat
2
tapping is 34.5 kN/m and the area ratio, m is 4, calculate the rate of flow, assuming a
coefficient of discharge is 0.97.

Solution to Example 4.10

From Equation (3),

2gH
Q = c A
d
1
actual
m 2 − 1
The difference of pressure head, H must be expressed in terms of the liquid
following through the meter,

p
H = m = 4, Cd = 0.97


34 5 .  10 3
=
9 . 0  . 9 81 10 3

. 3 142 ( 075.0 ) 2
A1 = = . 0 00441 m
2
4

= 92.3 m of oil

So,

2 . 9 81 . 3 92
Actual discharge, Qactual = 97.0  . 0 00441
16 − 1

Qactual = 0106.0 m 3 s /

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