Is absolute pressure same as gauge pressure?

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Discussion Overview

The discussion centers on the relationship between absolute pressure and gauge pressure, exploring definitions and mathematical representations of both concepts. Participants examine how these pressures are measured and their implications in fluid dynamics.

Discussion Character

  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants define gauge pressure as the pressure in a fluid exceeding atmospheric pressure, while absolute pressure is described as the total pressure at a point, equating to the sum of gauge pressure and atmospheric pressure.
  • One participant asserts that atmospheric pressure cancels out in the equation relating absolute and gauge pressures, leading to the conclusion that absolute pressure equals the pressure in the fluid.
  • Another participant questions the subtraction of atmospheric pressure from the fluid pressure, suggesting that absolute pressure should be expressed as the sum of gauge pressure and atmospheric pressure.
  • A different viewpoint emphasizes that gauge pressure reflects the pressure difference between the measured pressure and atmospheric pressure, while absolute pressure is the difference between the measured pressure and a vacuum state.

Areas of Agreement / Disagreement

Participants express differing views on the definitions and calculations of absolute and gauge pressure, indicating that the discussion remains unresolved with multiple competing interpretations.

Contextual Notes

Some assumptions about the definitions of pressure types and the conditions under which they are measured may not be explicitly stated, leading to potential misunderstandings in the mathematical relationships discussed.

avito009
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From what I have read:

Gauge Pressure: The amount by which the pressure measured in a fluid exceeds that of the atmosphere.

and

Absolute pressure: Total pressure at a point in a fluid equaling the sum of the gauge and the atmospheric pressures.So Absolute pressure= Patm+ P-Patm= P (Which is pressure in a fluid). Atmospheric pressure cancels each other in the equation.
 
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avito009 said:
So Absolute pressure= Patm+ P-Patm= P (Which is pressure in a fluid). Atmospheric pressure cancels each other in the equation.
Yes. So the answer to your question in the title is no.
 
Why are you subtracting Patm from P? Pabs = Pgauge + Patmos.
 
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Jobrag said:
Why are you subtracting Patm from P?
I support the question.
avito009, The instruments measures the pressure actually measured the pressure difference. The gauge pressure is the difference between measured pressure and atmosphere.pressure and the absolute one is the pressure difference between measured pressure and prussure of vacuum (zero).
 

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