Page 28 - BASIC CONCEPTUAL OF THERMOFLUID

CHAPTER 2: FLUID APPLICATION

Example 2.8
A meter venturi with diameter of 400 mm at the inlet and 200 mm at the throat. It is horizontal and used to
measure the water flow rate. A differential manometer is used and shown the different level reading of 60 mm.
Calculate the real discharge. Given Cd = 0.95.

Solution:

A1 = 0.125 m , =

ℎ = 0.06 × 12.6 = 0.756

2 ℎ
=
− 1
√2 × 9.81 × 0.756
=
− 1
√ × . × .
= = 1.2837 / ;

Q = × × = 0.95 × 0.125 × 1.2837

= 0.152 /

Bernoulli’s Equation has some restrictions in its applicability, they are:

· the flow is steady
· the density is constant (which also means the fluid is compressible)
· friction losses are negligible
· the equation relates the state at two points along a single streamline (not conditions on two different
streamlines).

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