F23 4520 HW 3b - Pumps
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University of Colorado, Boulder *
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4520
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Aerospace Engineering
Date
Apr 3, 2024
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2
Uploaded by ElderLoris4061
F23 CHEN 4520 Homework 3b – Pump Design
130 pts ~ Due Thursday, 9/21 by 11:59 pm on Canvas
Design and determine the specifications of three separate systems of pumps used in algae farming that transport
brewery waste to the rooftop concentration unit for processing. (Note: this was actually done in a partnership
between Upslope Brewing and Boom Algae here in Boulder on Upslope’s roof.) There is 75m of piping between
the pump outlet and the entrance to the next unit, and the piping rises 20m in elevation. The pump has a control
valve present. You can get a discount on Fristam pumps so you want to utilize them regardless of whether or
not they are the ideal type of pump for your system. Specs:
‐
The pumping rate corresponds to the required algae growth rate of 400 kg/hr and a conc of 2.6 g/L
‐
Though not the actual composition, we will model this as 90 vol% water and 10 vol% ethanol at 140°F.
‐
You can get the density from Aspen HYSYS (it does not change much from the inlet to the outlet so you
can use the inlet value)
‐
You wish to increase the pressure from 14.7 psia to 114.7 psia
‐
You can obtain the NPSH
A
by modeling in Aspen HYSYS.
The required head must be determined and an overall capacity in gpm calculated. You must come up with
three
different pump configurations – each using different pump models from one another – that can achieve this
head and capacity; for example, you might propose a configuration with a small number of large pumps, a
configuration with many small pumps, etc. At least one of your pump systems must utilize multiple pumps in
series and one must utilize multiple pumps in parallel (you could also have a system with a single pump or pumps
in series and parallel).
In each case, you will use required head and capacity in conjunction with a curve from the given Fristam Pump
Curves to size each pump. You must show that the pump has been sized to avoid cavitation. Please pay close
attention to the beginning of the pump curves document for information on pump type, how to read the pump
curves correctly and how to size the pump to the curves. Both psi and head (ft) are given on the y‐axis of the
curves; research which one to use and why. (Important: only one is correct because these Fristam curves convert
between psi and ft using the density of water at 70°F and we have a different feed.)
Please turn in an Excel document which includes all calculations and a Word document with the following info
written in a professional manner:
1.
(8 pts) Total required pressure difference (psi). If you utilize any heuristics please state them here.
2.
(3 pts) Corresponding required head (ft) and density used.
3.
(2 pts) Will you use ft or psi on the Fristam pump curves and why? (i.e. one is the industry standard;
why?)
4.
(6 pts) Describe the Fristam FP, FPX, and FPR pump lines, their pros and cons, and when would you prefer
each. Cite your reference(s).
5.
(3 pts) Give your overall capacity in gpm.
6.
(87 pts)
For each of your three (3) pump designs
give the following:
a.
(6 pts) Show screenshots of the following in Aspen HYSYS.
IMPORTANT NOTE: you do not need to fully simulate your three pump designs or turn in PFDs
of your designs; you only need to show how you got NPSH
A
values for each configuration. Also,
to make two pumps in parallel get a “Tee” from the “Piping & Hydraulics” tab.
i.
One screenshot showing the pump NPSH
A
. If you have multiple pumps in series please
show the NPSH
A
values for just the first and second pump. If you have multiple pumps
in parallel please shown the NPSH
A
values for two of the pumps.
ii.
One screenshot showing the stream inlet conditions (including density) to the first pump
(double click on inlet stream and got to Worksheet/Properties).
b.
(4 pts) Copy of the Fristam curve chosen to size the pump showing: (1) your operating point on
the curve, (2) circled impeller value, (3) circled HP value, and (4) how you determined NPSH
R
c.
(2 pts) Number of units and capacity per unit in gpm. How many units are in series and parallel
and why?
d.
(2 pts) Chosen pump: model #, including FP/FPX/FPR (could be a combo of two or three as given
in pump curve title), RPM, Inlet & Outlet Diameter.
e.
(2 pts) Impeller (mm) and why you chose this.
f.
(4 pts) Motor horsepower, BHp, and why you chose this. Give both the HP you read from the
plot and the BHp value you will use in your efficiency calculation; why are these different and
how did you calculate BHp?
g.
(2 pts) Theoretical horsepower, THp
h.
(4 pts) Pump efficiency; comment on this (is it good, bad, why?).
i.
(3 pts) NPSH
R
values; will we avoid cavitation and how do you know?
7.
(1 pt) What pump type (centrifugal, reciprocating, rotary,…) are the Fristam pumps?
8.
(2 pts) Would Fristam pumps have been your ideal pump type for this system if you had not gotten a
discount and why or why not?
9.
(6 pts) Compare your three designs, giving the pros and cons of each. Which design is your final
recommendation to the client and why?
10.
(4 pts) Comment on your NPSH
A
values for your different systems. Were they the same or different
(higher or lower?) for pumps in series/parallel and why?
11.
(4 pts) If a company wanted to use your recommended pump system, what are further design
considerations for implementation?
12.
(4 pts) What are 4 things you could you do to increase pump efficiency?
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