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Defying Gravity

Mark_46
Mark_46 Member Posts: 312
in THE MAIN WALL
Hey Brad,

Sensing you have a penchant for the theoretical like I do I had a feeling you would respond to this one :o).


Thanks for confirming what I thought might be true.
I also found the distinction between frictional and dynamic losses interesting. It makes my total understanding of head feet more complete.


Chatting with you online should be equivalent to so many semester hours of undergrad credit :o).

Comments

  • Mark_46
    Mark_46 Member Posts: 312
    Vertical Rise

    Does gravity effect the flow within a pipe circuit where the flow is generated by a circulator?

    If there is a supply pipe of let's say 20 feet in length going up and another the same length and diameter coming down, do the effects of gravity cancel each other out? Or is there additional 'head feet' induced/reduced?
  • Brad White
    Brad White Member Posts: 2,399
    Anti-Gravity Device

    In a closed system, gravity has no effect provided that the system is full over the top. As you suggest, the forces of gravity cancel out, just like a ferris wheel. Think of it as a form of siphon whereby the falling displaced water on one side has to be replaced by water coming up the other side.

    The circulator (correct term for a pump when in a closed system) absorbs the friction and dynamic losses along the fluid's path. Friction happens at pipe walls and dynamic losses are the forces incurred when flow changes direction, just to be clear.

    In an open system, such as a cooling tower, the lift head (height from the static or non-operating level to the operating level) has to be added to the other friction and dynamic losses.


    For a REAL anti-gravity device, attach a piece of buttered toast to the back of a cat. Everyone knows that toast always lands with the buttered side down and that cats always land on their feet. Voila!
    "If you do not know the answer, say, "I do not know the answer", and you will be correct!"



    -Ernie White, my Dad
  • Mark_46
    Mark_46 Member Posts: 312


    Hey Brad,

    How did I know you probably would respond to this one :o).

    Thanks. You answered my question while pointing out the distinction between frictional and dynamic losses - all with a little comic relief. I knew cats always landed on their feet but not buttered toast. I guess you do learn something new everyday.
  • Plumb Bob
    Plumb Bob Member Posts: 97


    > In a _i_closed_/i_ system, gravity has no effect

    > provided that the system is full over the top. As

    > you suggest, the forces of gravity cancel out,

    > just like a ferris wheel. Think of it as a form

    > of siphon whereby the falling displaced water on

    > one side has to be replaced by water coming up

    > the other side.

    >

    > The circulator (correct term

    > for a pump when in a closed system) absorbs the

    > friction and dynamic losses along the fluid's

    > path. Friction happens at pipe walls and dynamic

    > losses are the forces incurred when flow changes

    > direction, just to be clear.

    >

    > In an open

    > system, such as a cooling tower, the lift head

    > (height from the static or non-operating level to

    > the operating level) has to be added to the other

    > friction and dynamic losses.

    >

    > For a REAL

    > anti-gravity device, attach a piece of buttered

    > toast to the back of a cat. Everyone knows that

    > toast always lands with the buttered side down

    > and that cats always land on their feet. Voila!



This discussion has been closed.

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