A fluid flows though a horizontal 0.1 inch diameter pipe. When the Reynold number is 1508, the head loss over a 20-ft length of the pipe is 6.2 ft. Determine the fluid velocity.

Respuesta :

Answer:

The fluid velocity V = 1.98 ft/s

Explanation:

From the information given:

The fluid velocity can be determined from the head-loss [tex]h_L[/tex] of a laminar pipe and it is expressed as:

[tex]h_L = f\dfrac{l\times V^2}{D \times 2g}[/tex]

where;

f = frictional factor ; l = length; D = diameter; V= fluid velocity and g = acceleration due to gravity.

And;

[tex]f = \dfrac{64}{Re}[/tex]

For fluid movement in a laminar flow, the Reynolds number (Re) is usually lesser than 2100.

Given that:

Re = 1508 < 2100   ( laminar flow)

Then;

[tex]f = \dfrac{64}{1508}[/tex]

f = 0.04244

Also;

the head-loss [tex]h_L[/tex] = 6.2 ft

frictional force f = 0.04244

length = 20-ft

acceleration due to gravity (g) = 32.2 ft/s²

Replacing all the values into the equation [tex]h_L = f\dfrac{l\times V^2}{D \times 2g}[/tex]; the fluid velocity is:

[tex]6.2 = 0.04244 \times \dfrac{20 \times V^2}{0.1 \times \dfrac{1}{12} \times 2\times 32.2}[/tex]

[tex]6.2 = 0.04244 \times \dfrac{20 \times V^2}{0.53667}[/tex]

6.2 × 0.53667 = 0.04244 × 20 × V²

3.327354  = 0.8488 × V²

[tex]V^2= \dfrac{3.327354} { 0.8488}[/tex]

[tex]V^2=3.92[/tex]

[tex]V = \sqrt{3.92}[/tex]

V = 1.98 ft/s