Question

Water is pumped at steady uniform flow rate of 0.01 m³/s though a horizontal smooth circular pipe of 100 mm diameter. Given that the Reynold number is 800 and g is 9.81 m/s², the head loss (in meters upto one decimal place) per km length due to friction would be ________.

Answer 1

Q = 0.01 m³/s

d = 100 mm

R_e = 800

g = 9.81 m/s²

\({h_f} = \frac{{fl{V^2}}}{{2gd}}\)

Since Re is less than 2000 the flow will be laminar flow

Hence, \(f = \frac{{64}}{{{R_e}}} = 0.08\)

\(\begin{array}{l} {h_f} = \frac{{fl{Q^2}}}{{12.1{d^5}}}\\ = \frac{{0.08 \times 1000 \times \left( {0.01} \right)2}}{{12.1 \times {{\left( {0.1} \right)}^5}}} = 66.10\;m \end{array}\)