More questions on Reynolds numbers and defying gravity...

Mark Eatherton

Food for thought.



I am not disputing the engineering communities thought processes as it pertains to Reynolds numbers, but.... and there's a butt in every crowd, ain't there...



How did the Dead Men deal with this in their subtle gravity circulation systems?



We talk about not wanting laminar flows, and the need for turbulence, but what about a one pipe gravity system that DEPENDS upon stratification within the pipes in order to effect good heat transfer.





HMMMmmm???



Just stirring the thought pot :-)



ME

Gordan

Apples to oranges?

Nothing wrong with laminar flows in distribution piping - in fact, anything that reduces head loss would still be a good thing in that context, it would seem. As long as it doesn't create another issue (like inadequate air entrainment.)



Now, in emitters, you want as much of the fluid to transfer its heat to the emitter as possible. In an emitter that looks like a long, skinny pipe through which water is forcibly circulated, turbulence is the mechanism for ensuring that, but in the big, fat, slow water pools that constituted emitters of old, with both tappings on the bottom, hot water checks in and doesn't check out until it becomes relatively cool water. Meanwhile, convection currents within the emitter would take care of the rest; the hot water in the middle eventually makes it to the top and falls down the outside, giving up its heat.



At least that's how my mind's eye sees it.

Gordan

I think I just pointed out the obvious...

...without really addressing your question.

Paul Rohrs_14

Baked Noodles Anyone?

Wow, that can really work out the kinks in the ole' grey matter if you really think about this.

Of course I refreshed my thinking with a quick trip to wikipedia.

"laminar flow occurs at low Reynolds numbers, where viscous forces are dominant, and is characterized by smooth, constant fluid motion, while turbulent flow occurs at high Reynolds numbers and is dominated by inertial forces, which tend to produce chaotic [color=#0645ad]eddies[/color], [color=#0645ad]vortices[/color] and other flow instabilities."

I was fine until you mentioned a 1-pipe system. 

Seems to me that the water creates its own monoflo tee and the friction from water of the outside flow is generated against the water flow in the (inner) annulus of the external flow. (I reserve the right to re-phrase that)

Now I am sitting of the feet at the professor and ask:

Will you need the properties of temp, flow, etc of supply and return to get the answer you are seeking?

My new name, " Be Juan with the Pipe".

Juan