Questions tagged [pipelines]
119 questions
39
votes
2 answers
What is the purpose of these diversions in a natural gas line?
The campus where I work has a long covered walkway (~.5 mile) which has several labeled pipes running under the roof (chilled water, fuel oil, air...). All of the pipes run dead straight except for the natural gas lines, which have little loops…
Gretchen
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22
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3 answers
How to know whether the flow is supersonic in a nozzle?
For a project I had built a convergent divergent nozzle designed for Mach number = 3. In that project, I could know the flow has gone supersonic by seeing the manometer fixed between the throat and the divergent section (drop in pressure, as the…
Subodh
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12
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4 answers
How thick is it reasonable for the walls of a steel gas pipeline to be?
The TurkStream project site claims the gas pipeline will use pipes made from 39 millimeters of high-quality carbon manganese steel with additional plastic coatings on both sides. Yes, they claim 39 millimeters (roughly 1,54 inches) of steel walls -…
sharptooth
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10
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2 answers
How is gas flow through (extremely long) pipelines monitored and controlled?
(This is closely linked with measuring the Mach number inside a nozzle but it is not regarding the supersonic flow)
Friction and heat transfer have effects on the Mach number of the compressible flow (Fanno and Rayleigh flow). As it is extremely…
Subodh
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9
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2 answers
What is the maximum length of oil pipelines?
This is inspired by the discussion and controversy surrounding the Keystone Pipeline.
The main part of the Keystone Pipeline system is about 3,400 kilometers long, stretching across a large portion of the United States. The Keystone XL extension…
HDE 226868
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9
votes
1 answer
Estimating Darcy Friction Factors for Critical Flow
The Darcy-Weisbach equation is used to calculate the frictional pressure losses in pipes transporting incompressible fluids. This equation uses a dimensionless Darcy friction factor, also known as the Moody factor, to account for the relative…
Jim Hargreaves
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8
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2 answers
How Can I Determine Multiple Discharges from a Pipe Network? (Knowing the Inlet Conditions)
I have little/no experience with pipe networks and have been searching for a methodology to calculate the discharge from multiple outlets of an oil pipe network with a single inlet. As far as i can tell I have too many unknowns to use something like…
Petrichor
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8
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1 answer
How can I calculate the stresses and limits for the physical lowering of in-service pipelines?
Sometimes underground pipelines are exposed due to vertical scour or lateral migration of streams (or other erosion). One option is to lower the (in-service) pipeline to a new depth that provides sufficient ground cover.
How can I determine the…
JustInTheWoods
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7
votes
2 answers
Heating circuit: Galvanized steel with press fitting vs welded steel pipes
What are the downsides for galvanized steel pipes + press fittings vs. welded steel pipes in a heating application? Diameter would be DN25/1".
Background: The customer specifies only steel, only welded connections for heating pipes starting at this…
mart
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7
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2 answers
How are blanking spades entered into gas pipelines?
I often see specifications for refurbishing works on gas pipelines calling for blanking spades, to separate the area worked on from the rest of the gas system. This is in addition to closing valves.
Googling showed me some pictures of how blanking…
mart
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7
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4 answers
Why is the friction factor in laminar flow independent of pipe roughness?
The Darcy friction factor is defined as:
$$f_D =\frac{64}{Re}$$
with $Re$ I mean Reynolds number (global).
I was wondering why Darcy in laminaire flow is independent of pipe roughness (wall roughness)?
That is not the case in turbulent and transient…
user14407
7
votes
3 answers
Force required to empty a syringe
How would you go about solving the following problem. I believe Bernoulli's equation needs to be employed, but I'm not sure how.
Find the magnitude of the force that needs to be applied to a piston of a 20ml syringe with 1cm diameter tube to drain…
thelastpanda
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7
votes
4 answers
Why do water mains break in the winter?
It may just be my perception, but it seems like water main breaks (at least in Pittsburgh PA) are more common in the winter during the cold weather. It may just that they are more news worthy in the winter (water+cold=ice > news).
Are water mains…
James Jenkins
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6
votes
2 answers
Is there a way to reduce leaks and infrastructure damage when turning water on and off at the scale of city?
Cape Town, South Africa is experiencing an extremely serious drought, with estimates putting April 21, 2018 as the day that the city will be forced to shut off all municipal water supplies and begin water rationing, except to essential services such…
Jonathan Rayner
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5
votes
2 answers
One way plastic rubber pipe
I am working on a project for college, and I am stuck on one idea that I don't really know how to represent it.
Basically what I want to do is something like a pipe, that if a put a kind of cylinder on inside from the top side, the cylinder will…
peterpeterson
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