Show for Newtonian fluids in laminar flow that the Fanning friction factor,
f,
is given by f=16/Re, where Re is the Reynolds number. SOLUTION
Geankoplis, 2.8-4, page 110 (Flow through an expanding bend). SOLUTION
Geankoplis, 2.7-12, page 109 (Pipeline pumping of oil). SOLUTION
In the equipment shown in the figure below, a pump draws a solution of
specific gravity 1.84 from a storage tank through a 3-in schedule 40 pipe.
The pump discharges through a 2-in schedule 40 pipe to an overhead tank.
The end of the discharge pipe is 50. ft above the level of the solution
in the feed tank. Friction losses in the entire piping system (except for
the pump) are 8 ft-lbf/lbm; the friction losses in
the pump are 8 ft-lbf/lbm. The velocity on the suction
(inlet) side of the pump is 3.0 ft/s. What is the pressure drop (in psi)
across the pump? You may neglect the difference in elevation between the
inlet and outlet of the pump. See Geankoplis p892 for the dimensions of
schedule 40 pipe. SOLUTION
What is the difference between schedule 40 and schedule 80 pipe?
At what value of Reynolds number does the transition from laminar to turbulent
flow occur in pipes?
What is the roughness of commercial steel?
The chart on page 88 of Geankoplis gives values of Fanning friction factor
versus Reynolds number for flow in a tube. We showed in class that dimensional
analysis of the equations of change tells us that friction factor is only
a function of Reynolds number (for flows without free surfaces). Is the
analysis we carried out to arrive at that conclusion valid for the flow
of gasses in pipes? Why or why not?
Your grandfather has a cottage at the lake and needs to install a pump
to feed water to the house. He plans to pump water at night to fill a storage
tank he has installed next to the cottage. The pipes and fittings he has
chosen to use for the installation are listed in the table below. The pumps
in the pumping catalog your grandfather has are rated by their value of
horsepower (hp). What is the minimum horsepower rating of a pump does capable
of providing a flow rate of 5 gallons per minute of water at the tank?
Assume the pump efficiency is 65% and that the pipe is PVC, i.e. completely
smooth. SOLUTION
Type of fitting
Number of fittings of this type in Grandpa's water system
Straight pipe, 2inch, schedule 40
95 feet
90o elbow
10
coupling
8
Globe valve
1
Gate valve
4
Disk water meter
1
If Grandpa (see problem above) purchased the pump whose characteristic
curve is shown in Figure 3.3-2 on page 136 of Geankoplis, and if he operated
it at 1750 RPM, what would be the flow rate of water into the tank? SOLUTION
HONORS PROBLEM: Using Excel or some other mathematical program, how would
you do example 2.10-4 without a trial-and-error solution? (see me to discuss
solution).
