Is Total Pressure Different at Different Points Along a Pipe?

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Discussion Overview

The discussion revolves around the concept of total pressure in a pipe system, particularly whether total pressure remains constant along different points in a pipe. It explores theoretical and practical implications, including the effects of energy loss due to friction and other factors.

Discussion Character

  • Debate/contested
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • Some participants assert that total pressure is a sum of static and dynamic pressure and is generally considered the same along a pipe.
  • Others argue that in real-world scenarios, total pressure varies due to energy losses from friction and viscous effects as water flows through the pipe.
  • A participant questions whether total pressure remains constant in a closed system, indicating a potential disagreement on this principle.
  • It is noted that head loss occurs as fluid moves through the pipe, which affects total pressure.
  • Some participants clarify that the total pressure at the discharge point is not equal to that at the suction point, emphasizing the role of pumps in this context.
  • One participant suggests that the initial statement about total pressure being constant is conditionally true only for short lengths of the system where head losses are negligible.
  • Another participant mentions that secondary losses, such as those from fittings and valves, are often neglected, but the length of the pipe does matter.

Areas of Agreement / Disagreement

Participants express differing views on whether total pressure is constant along a pipe, with some asserting it is not due to energy losses, while others maintain that it can be considered constant under certain conditions. The discussion remains unresolved regarding the general applicability of these claims.

Contextual Notes

Limitations include assumptions about negligible head losses over short lengths and the neglect of secondary losses in practical applications. The discussion does not resolve the implications of these factors on total pressure.

Yuri B.
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Total pressure is a sum of the static pressure and the dynamic one, and is said to be the same along a pipe/duct.
In the water pipe gauge (static) pressure is maximal after the pump and minimal at the pipe outlet, but the speed and the density being the same, the dynamic pressure is the same everywhere. So, the total pressure is different at different points ?
 
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Yes: In a real-world situation, the stream of water loses energy as it flows, due mostly to friction and viscous losses. This is why pumps require input energy.
 
russ_watters EXCELLENT
 
Does total pressure stay the same everywhere in a closed system ?
 
Not according to Russ.
The loss as the flud moves down the pipe is called, well, head loss.
 
The TP at discharge is not = the TP at suction ?
Why ?
 
Yuri B. said:
The TP at discharge is not = the TP at suction ?
Why ?
That's the entire purpose of a pump.
 
because u give the pump electric power and it transimits it to hydraulic power
thats the reason YURI
 
I got it so: the first statement (in my OP) - which one can meet not once in the writings on the subject - is true conditionally for only short lengthes of a system where head losses are considered negligeable.
Thank you!
 
  • #10
my friend we always here neglect secondary losses like fittings and valves but length no and also it depends on the length ur talkin abt
 

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