Fluid hydraulics question

[debwaldy]

Homework Statement

Hi I am trying to solve this problem.I think i have the first part sorted but the second part of the question is throwing me.
Given the network of pipes shown below determine the flowrate through each pipe. Use the hazen williams formula with Ch = 100.
I think I have this part done correctly.
However:
If the static pressure head at the entry point A to the network is 35m find the static pressure at the two exit points D and F, assuming the network is horizontal?

Homework Equations

Hazen williams formula: hf = 12.25*10^9 L Q^1.85/((Ch^1.85)*(D^4.87))
Energy Eqn z1 + P1/rho*g = z2 + P2/rho*g

The Attempt at a Solution

I presume you use the energy equation for the second part and since the network is horizontal then the elevation heads will always cancel.Does it matter which way i go around the circuit to get to these two exit points.Do i just have to subtract the head loss due to frction from the given head to calculate the new static head.Also is this head loss accumulative because the pipes are in series?or am I way off the mark?any tips would be grately appreciated
Thanks Debs

 

[KataKoniK]

Dear Debs,

It seems like you are on the right track for the second part of the problem. Since the network is horizontal, you are correct in assuming that the elevation heads will cancel out in the energy equation.

To calculate the static pressure at exit points D and F, you will need to use the Hazen Williams formula to determine the head loss due to friction in each pipe. This head loss will then need to be subtracted from the given static pressure at entry point A to calculate the static pressure at each exit point.

Since the pipes are in series, the head loss will be cumulative as you move through the network. It is important to make sure you are using the correct pipe lengths and diameters for each section of the network in your calculations.

As for which way to go around the circuit, it shouldn't matter as long as you are consistent in your calculations and using the correct pipe lengths and diameters for each section.

I hope this helps and good luck with your problem solving!

 

[piercas]

I would suggest that you first review the equations and make sure you have a clear understanding of how to use them. The Hazen Williams formula is used to calculate the head loss due to friction in a pipe, while the energy equation is used to calculate the total energy at different points in a system. In this case, you are correct in assuming that the elevation heads will cancel out since the network is horizontal.

To find the static pressure at points D and F, you will need to use the energy equation. You can choose any path to get to these points, as long as you include all the relevant head losses due to friction in the pipes. The head loss is cumulative, so you will need to add up the head losses for each pipe in the path you choose.

To calculate the new static head, you will need to subtract the head loss from the given static pressure at point A. This will give you the static pressure at the exit points D and F.

I would also suggest double checking your calculations and units to ensure accuracy. If you are still having trouble, I would recommend seeking help from a tutor or classmate. Good luck with your problem!