Question

Oil (specific gravity of 0.80 and a viscosity of 0.000042 lbf/ft2) at a temperature of 80 F flows through two separate pipes 10 and 12 inches in diameter. if the mean velocity of flow in the 12 in. pipe is 6 ft/s, the velocity of flow in the 10 in pipe will be:

Answer 1

Answer:

The velocity of flow in 10in pipe is 4.16 ft/s.

Explanation:

Given that

Specific gravity = 0.8

Viscosity =0.00042$lbf/ft^2$

For pipe 1

$V_1=6 ft/s,d_1=12\ in$

For pipe 1

$V_2,d_1=10\ in$

If we assume that flow in the both pipe is laminar

For laminar flow through circular pipe

$\dfrac{\Delta P}{L}=\dfrac{32V\mu }{d^2}$

So same pressure drop we can say that

$\dfrac{V_1 }{d^2_1}=\dfrac{V_2}{d^2_2}$

$\dfrac{6}{12^2}=\dfrac{V_2}{10^2}$

$V_2=4.16 ft/s$

So the velocity of flow in 10in pipe is 4.16 ft/s.