fluid-pipe network analysis type

waluyo

I remember last time when I use LISA 7, flow-pipe network analysis was available, then the latest version this analysis type disappear. Mecway also does not provide this analysis. How can I do the flow-pipe network analysis in Mecway. Is that possible to do that pipe network analysis?

[Deleted User]

victor is the developer of mecway and will have the best answer. but i know that he has cleaned up the code base a lot. removing things that were in error or not used enough to be worth updating.

waluyo

I used flow-pipe network analysis, and as far as I know, no errors, last time in LISA 7. I can get the same results with the finite element textbook having the flow-pipe network topic. That analysis is very useful. I hope Mecway can support this analysis.

Victor

It's like prop_design said. This was a relatively low value feature. It tended to mislead people who expected it to be practical for modelling actual pipe networks but it had big shortcomings like:

It ignores the Bernoulli principle which might be significant at diameter changes or intersections.
No convenient lumped elements like bends (extra losses) and pumps.
No provision for entrance regions – flow is assumed to be fully developed everywhere.
No gravity.


Since the Hagen-Poisueille law is analogous to Ohm's law, you could use electrical resistor elements instead:

Hagen-Poisueille: ΔP = 32μ * L/d² * v

Ohm's law: ΔV = 4ρ/π * L/d² * I

So if I've got my maths right, you can pretend:
I = v
V = P
ρ = 8πμ

where μ is dynamic viscosity and v is average velocity.

Victor

Also there may have been an error with the tapered pipe element. It was internally converted to a straight pipe with the same average diameter, though I think it should have had the same average cross-sectional area instead.