Question

Technicians have to determine the flow rate of water in a pipe with the aid of a venturi installation and a mercury au.oaeter. The expected water welocity is about 1.5 a/s. The pipe diameter is 40 mm and the venturi throat has a diameter of 20 mm. The venturi meter has a discharge coefficient C = 0.97. Determine what level difference can be expected in the manometer.

Answer 1

Manometric difference x=142.85 mm.

Step-by-step explanation:

Given :

Pipe diameter
`d_1=40 mm`

venturi meter
`d_2=20 mm`

We can know that discharge through venturi meter is given as

`Q=C_d\frac{A_1A_2√(2gh)}{\sqrt {A_1^2-A_2^2}}`

`A_1=1.24* 10^(-3),A_2=3.12* 10^(-4)`

`Q=A_1V_1`

`Q=1.24* 10^(-3)* 1.5=0.00186 m^3/s`

`0.00186=0.97\frac{1.24* 10^(-3)* 3.12* 10^(-4) √(2gh)}{\sqrt {(1.24* 10^(-3))^2-(3.12* 10^(-4))^2}}`

h=1.8 m

We know that
`h=x\left ((\rho_(hg))/(\rho_w)-1\right )`

Where x is the manometric deflection

⇒
`1.8=x\left ((13600)/(1000)-1\right )`

So x=14.28 mm

Manometric difference x=142.85 mm.