A farmer is to pump water at 200 C from a river to a water storage tank nearby using a 60
m long, x cm diameter pipe with two 450 threaded elbows and two threaded 900 smooth
bends. The water velocity near the river surface is 2.2 m/s, and the pipe inlet is placed in
the river normal to the flow direction of water to take advantage of the dynamic pressure.
The elevation difference between the river and the free surface of the tank is 3.5 m. For a
flow rate of 0.042 m3
/s and overall pump efficiency of 70%, determine the required
electric power input to the pump. Consider the exit loss, KL=1, for all types of pipe
connection to a tank. Use the Colebrook equation for calculating the friction factor.
(i) Now, investigate the effect of the pipe diameter on the required electric power input to
the pump. Let the pipe diameter vary from x1 cm to x4 cm. Show details sample calculations.
(5 marks)
Here, x1 is the last two digits of the student ID of the 1st group member. Same way, x2, x3,
and x4 are the last two digits of student ID of other student members of the group,
respectively. Consider these numbers in ascending order. The maximum number of
members in a group should be four.
(ii) Tabulate and plot the results and draw conclusions. How the diameter of the pipe affects
the required pump power. What is the optimum diameter for power input?
(3 marks)
(iii) If you change the elbows’ shape or numbers, will it change the required power input?
Please at least show two different combinations of elbows shape or numbers change. Show
your calculation and explain it. You can find the loss coefficient of your designated elbow
shape choice from the manufacturer’s datasheet or the book with the standard one.