Sciencey odd question just occured in my daily musings...

[ecowarm]

can we do t in 2" with the hand dies please

 

[quality]

100mm @ 4 bar straight run 25 miles = well enough for combi ( about 112 lpm) guestimated

 

[fuzzy]

dont worry they are electric, has anyone got a 25 mile extension lead?

in fact is the power the same, more or less on a long extension lead? what are the friction losses?

 

[quality]

I get the jist
The power output (work done ) will be what it is determined by the power input (work Supplied)

 

[WaterTight]

I'm not still convinced by (mainly because I don't understand half of them) the arguments given so far. So I'll modify the question..

Ingoring pumps or the nature of the force that has created the pressure, ignoring friction or other factors. Imagine there is a hyperthetical pipe potentially as long as the universe itself if need be. At one end is say 1.5 bar pressure. At the other end a tap. This pipe has no friction, it has not fluctuations of temperature. It's dead-level.

The question to which I want a yes or no answer is.....Could this pipe be long enough so the weight of the water itself to be moved by the standing pressure be so great that the pressure couldn't shift it? Yes or no people, time to vote...

*countdown music*

 

[unguided1]

NO there is no gravity in space therefore the water would be weightless

 

[tamz]

And if there were no friction it would be frictionless

 

[ecowarm]

so if you opened the hypothetical tap you would just release the pressure and that would be it

 

[WaterTight]

And exactly the same experiment but on Earth....?

 

[tamz]

If there is no friction then there are no friction losses so the pressure remains constant

 

[ecowarm]

If there is no friction then there are no friction losses so the pressure remains constant

But he said no pump so how do you maintain said pressure in a level pipe how ever long?

 

[tamz]

Never noticed that bit:shame:

So, if i've got this right, we have a level pipe of infinite length with no applied pressure but as it is on earth, it is subjected to gravity.
Cut the end off the pipe and it will empty...............eventually.

 

[ecowarm]

Glad we didn't get into the electric losses that some one posted as well

 

[mickie]

if your talking about a pipe in outer space their wouldnt be any pressure and if you opened each end water wouldnt flow anywhere, it would stay still, untill someone moved it, using a force of pressure or gravity moved the water down..

 

[tamz]

Ah, but we are now back on earth (post 59) so subject to the usual forces :lol:

 

[mickie]

water run level for a long distance, say 1000 miles, i dont think would work, due to the moons pull on water, just look at the sea, it goes in and out, but i think it would work if the water was raised up from the ground, as that would increase its pressure..its pressure would never come down over the 1000miles, but its flow rate would due to friction so you'd have to fit the currect sized pipe to cater for its run

if size didnt matter, the water board would be using 15mm pipe under our roads to feed everyones home.. i dont know the math in sizing water mains though

 

[tamz]

😕So the pipe might have a high and low tide:speechless:

 

[mickie]

well if run totally level without any real pressure, bar its own pressure due to its own weight on the earths gravitational pull and say we had no moon, if you opened each end water would flow out slowly, but factoring it the moons pull on water, depending on where the moon was water would naturally want to follow the moons path, would it not ?

dont really understand the question, who'd want to fit a pipe without increasing its pressure

 

[tamz]

I suppose as long as the money was right , wgaf. Just keep laying pipe. No pressure as it is an infinate job!

I'm out:sleep1:

 

[fuzzy]

if your talking about a pipe in outer space their wouldnt be any pressure and if you opened each end water wouldnt flow anywhere, it would stay still, untill someone moved it, using a force of pressure or gravity moved the water down..

there is gravity on the moon, its just reduced 1.6n/s/s instead of 9.8n/s/s. So i pipe on the moon 25 miles long would take 1/6 of the time to empty. However, if it were pumped and pumped upwaards the restriction due to gravity would be less, its all pros and cons lads

 

[fuzzy]

Ah, but we are now back on earth (post 59) so subject to the usual forces :lol:

stop trying to simplify things tamz

 

[fuzzy]

NO there is no gravity in space therefore the water would be weightless

are you just an earth plumber? not got your 'moon' ticket? Ask at your local centre, when your doing heat pumps

 

[WaterTight]

Well I'm still a bit confused but I think the answer is too many other factors would get in the way of the experiment.

I suppose what I want to imagine is say you are on this magical world for this experiment - you have this level stretch of 1000 miles of pipe, which is not effected by friction, is neither subject to the effects of gravity nor the effects of no gravity, where the only thing being tested, somehow - magically - is whether the mass of this water itself can hold back pressure when applied.

So this pipe would be full of water but not pressurised. Just at the pressure it normally would be at. At the far end is a tap which will be opened shortly. Then, 1000 miles back the other away is a valve which is closed. On the other side of the valve is more pipe, containing water which is pressurised to 1.5 bar. If you open the valve the pressurised water comes into contact with the non-pressurised water, sitting there for it's 1000 mile stretch - if you then open the tap 1000 miles away does water come out or not?

 

[WaterTight]

And if this has now been answered already and I'm just too thick to get it and everyone else does I apologise and will stop bothering everyone :43:

 

[unguided1]

not answerd yet dont forget if a pipe is a 1000 miles long layin on a planet, the natural curvature of the planet will allow air in when you open the pipe allowing the water to pour out