Question

Question 1) Water at 20 C flows through a galvanized pipe at an average speed of 2.5 m / s. The diameter of the pipe is 150 mm. The roughness of the pipe surface is 60 μm. Calculate the pressure drop in this pipe since the total length of the pipe is 300 meters. Take the necessary values for calculations from tables and diagrams.

Answer 1

V = 2.5 m/s

d = 150 mm or 0.15 m

ε = 60 μm or 0.06 mm

L = 300 m

At 20⁰C,

ρ = 999 kg/m³

μ = 1.002 * 10^-3 N-s/m²

Re = ρ V d / μ

Re = 999 * 2.5 * 0.15 / 1.002 * 10^-3

Re = 3.73 * 10⁵

ε/d = 0.06 / 150 = 0.0004‬

From Moody Chart,

f = 0.017

h_f = f L V² / 2 g d

h_f = 0.017 * 300 * 2.5² / 2 * 9.81 * 0.15

h_f = 10.83 m

ΔP = ρ g h_f

ΔP = 999 * 9.81 * 10.83

ΔP = 106136 N/m²

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