Microsoft Word - Pipe Systems Assignment.docx
Pipe Systems Assignment
This is an individual assignment (worth 3%) that is due via Blackboard. Please see the ru
ic
on Blackboard for all requirements and marking criteria.
You must start with the appropriate values or you will get zero. Full solutions will be posted
on Blackboard the day after the due date. Once the answers are posted, assignments can no
longer be submitted.
Propane at 25oC is flowing in the parallel pipe system shown. Calculate the pressure
difference pA-pB by following the steps outlined below, do NOT make any assumptions.
The volumetric flow at A is in L/min and is equal to the first three digits of your N-
number after the initial zeros (for example: n XXXXXXXXXXgives QA = 123 L/min and
n XXXXXXXXXXgives QA = 987 L/min).
The lower
anch has a total length of 45 m. The significant minor losses in the lower
anch are the standard 90o elbows (3 of them) and the valve. All other sources of
minor loss can be ignored.
All pipes are commercial steel with dimensions as shown in the diagram.
A and B are at the same elevation (zA = zB)
1. Set-up the solution:
a. Draw the layout of the pipe system (straight lines are fine). Include the direction of
flow. Label the pipe types and dimensions. Show the 4 locations of the minor
losses that you need to consider. Include any other relevant information.
. Write a list of all of the given information and necessary standard values (that you
may need to look up in the textbook). Make sure to include information about:
i. The fluid type and properties ( and )
ii. The pipes (L, D, A, )
iii. The minor losses (K)
iv. The flow at A (include your student number)
v. Anything else (z, g, …)
c. Write a statement about what value you are asked to find.
d. List every equation that you might need to use.
DN 15 Schedule 80
Solution
2. Write the General Energy Equation between A and B. Simplify it as much as possible,
then rea
ange it to so that the two pressure values are alone on one side of the equation.
Remember this equation must work for fluid flowing through the upper
anch AND the
lower
anch. That means that hupper = hlower.
3. Calculate hLupper using the Darcy formula. Use the “fully tu
ulent” value for f since the
velocity is unknown. You will not end up with a value for hLupper but a relationship that
includes the unknown vupper.
4. The hLlower value includes the major losses and the 4 minor losses.
a. Calculate hLlower using the Darcy formula, just like you did for hLupper.
. Calculate the minor losses at the 3 elbow and one valve. Again you will have
unknown vlower terms.
c. Sum the major loss, 3 elbow and value losses. Again, you will not end up with a
value for hLlower but a relationship that includes the unknown vlower term.
5. Set hLupper = hLlower and simplify. You will end up with an expression that has two unknowns
(vupper and vlower). Write your equation so that vupper is alone on one side of the equation.
6. Write the continuity equation for the system. Substitute in and rewrite it in terms of QA
(based on your n-number), vupper and vlower. Then write your equation so that vupper is alone
on one side of the equation.
7. Set vupper from the continuity equation (step 5) equal to vupper from the general energy
equations (step 6), and solve for vlower.
8. Hu
ay you have a velocity value! Use that velocity and the Moody Diagram to calculate
the actual friction factor, f. Check that the calculated f is close to the fT value you
assumed back in steps 3 and 4. In theory, if it is very different then redo all your
calculations with the new, better f. For this assignment your values should match.
9. Use vlower to calculate hLlower, and then substitute that value into your simplified general
energy equation (from step 2) and find what you were actually looking for (pA-pB).
10. Check your answer by finding vupper (from step 5 or 6), then find hLupper. Confirm that hLupper
is the same as hLlower.
11. Write a really nice sentence answering the original question include units.
12. Check the Ru
ic on Blackboard to make sure you didn’t miss anything.
13. Submit the Assignment as a SINGLE document (word or pdf).