I need to select a suitable diameter for my pipes

  • Thread starter Thread starter Young.Eng.SA
  • Start date Start date
  • Tags Tags
    Diameter Pipes
Click For Summary

Discussion Overview

The discussion revolves around selecting suitable diameters for pipes in a pipe network system designed using the Hardy Cross method. Participants explore various factors influencing pipe size selection, including flow rate, cost, volume, and pressure loss.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • One participant inquires about the optimization criteria for pipe size selection, suggesting factors like cost, volume, efficiency, and weight.
  • Another participant notes that pipe size affects pressure loss and fluid velocity, referencing Moody's diagram and the Hagen-Poiseuille equation as useful models.
  • A different participant suggests that any reasonable pipe size might suffice, emphasizing the iterative nature of the Hardy Cross method.
  • One participant expresses uncertainty about how far to go with assumptions for diameter selection based on a given flow rate of 15000 cubic meters.
  • Another participant mentions that they are considering both volume and cost in their decision-making process.
  • There is a correction regarding the properties of helium gas at high temperatures, with one participant asserting that helium does not solidify or liquefy under normal conditions on Earth.
  • A later reply suggests sizing the pipe to maintain low velocities, specifically recommending around 7 ft/s, while noting the complexities of dealing with compressible gases.

Areas of Agreement / Disagreement

Participants express differing views on the criteria for selecting pipe sizes, with no consensus on the best approach or assumptions to make. The discussion includes both technical considerations and corrections regarding gas properties, indicating unresolved points.

Contextual Notes

Participants have not fully agreed on the assumptions necessary for selecting pipe diameters, and there are varying opinions on the importance of different optimization criteria. The discussion also highlights the complexities involved in dealing with gas properties.

Young.Eng.SA
Messages
3
Reaction score
0
Hi guys,

Please help me out, I have a project here I need to design a pipe network system using Hardy Cross method.

I have drawn my pipe network and done my distribution of the flow rate according to the give discharge. but now I'm not sure which method I should use in selecting pipe sizes.

Pleasr help me out.

Regards
Young.Eng.SA
 
Engineering news on Phys.org
What is it that you are trying to optimize? Cost, volume, efficiency, weight? The only fluids related parameters pipe size effects is the pressure loss (head) in the piping system and the fluid velocity. All these relationships can be found using Moody's diagram and models such as the Hagen-Poiseuille equation.

http://en.wikipedia.org/wiki/Hagen–Poiseuille_equation
 
Surely any reasonable size will do?

The Hardy Cross method is really an iterative method for solving a system of linear simultaneous equations.
 
Hi,

I was also thinking of considering Hardy Cross. But I'm only given a flow rate of 15000 cubic meters and I believe I have to make assumptions for the selection of diameters but again how far in assumptions should I get with the above flow rate?

Also can you guys tell me: what are the properties of helium gas at 900 degrees celcuis. I believe this is an inert gas that can be solidified at high pressures
 
Hi,

I'm looking on both volume and cost only
 
Young.Eng.SA said:
Hi,

...Also can you guys tell me: what are the properties of helium gas at 900 degrees celcuis. I believe this is an inert gas that can be solidified at high pressures

IIRC, that's incorrect. I don't even think there's a industrial use for liquid helium.

Helium does not solidify or liquefy outside of extreme lab environs. At least on earth.
 
You want to size the pipe so that your velocities are fairly low. If its something generic, size it to about 7 ft/s. Dealing with gas is a little more complicated as its compressible, really depends on how much volume you want at your outlet
 

Similar threads

  • · Replies 7 ·
Replies
7
Views
2K
  • · Replies 31 ·
2
Replies
31
Views
5K
  • · Replies 3 ·
Replies
3
Views
1K
  • · Replies 3 ·
Replies
3
Views
3K
  • · Replies 10 ·
Replies
10
Views
4K
  • · Replies 19 ·
Replies
19
Views
3K
Replies
4
Views
2K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 21 ·
Replies
21
Views
3K
  • · Replies 15 ·
Replies
15
Views
4K