How Do Pumps Increase Pressure According to Bernoulli's Equation?

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Discussion Overview

The discussion revolves around the role of pumps in increasing pressure according to Bernoulli's equation, focusing on the mechanisms by which pumps add energy to fluids and the implications for pressure changes. The scope includes theoretical understanding and technical explanations related to fluid dynamics.

Discussion Character

  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Some participants propose that pumps add energy to fluids, causing movement and potentially increasing pressure, but they question the specific nature of this pressure increase.
  • There is uncertainty about whether pumps simply increase kinetic energy or if they also create a larger static pressure, with references to dynamic pressure and stagnation points.
  • One participant describes the operation of centrifugal pumps, noting that the impeller increases fluid velocity, which is then converted to pressure as the fluid passes through a diffuser or volute.
  • Another participant mentions the complexity of impeller design and its significance in fluid dynamics, suggesting that expertise in this area is valuable for understanding pump mechanics.

Areas of Agreement / Disagreement

Participants express differing views on how pumps affect pressure, with some focusing on kinetic energy and others on static pressure. The discussion remains unresolved regarding the exact mechanisms and definitions of pressure changes associated with pumps.

Contextual Notes

Participants have not fully clarified assumptions about the definitions of pressure types or the conditions under which pumps operate, leaving some aspects of the discussion open to interpretation.

fog37
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TL;DR
understanding how pumps work
Hello,

My understanding is that pumps (whatever type) add energy to the fluid and cause the fluid to move. The fluid can be either brought to a higher elevation or not.

I am unclear on how pumps "provide a larger pressure". Do they? If so, in what sense? Are pumps simply speeding up, i.e. increasing the kinetic energy, of the fluid (gas or liquid) that is pulled inside the pump case and the pressure increase discussed with pumps is nothing but the increase in "dynamic pressure" that the fluid would experience at if brought to rest at a stagnation point after it exist the pump?
 
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fog37 said:
My understanding is that pumps (whatever type) add energy to the fluid and cause the fluid to move. The fluid can be either brought to a higher elevation or not.
Typically it is said that pumps apply or create a pressure, which causes a fluid to move, similar to how you would say you apply a force to a box to push it across the floor.
I am unclear on how pumps "provide a larger pressure". Do they? If so, in what sense?
Two most common methods are pistons, which directly push on the fluid and centrifugal, which actually use a combination of centrifugal force from spinning the fluid and a hydrodynamic lift effect (like a wing).
Are pumps simply speeding up, i.e. increasing the kinetic energy, of the fluid (gas or liquid) that is pulled inside the pump case and the pressure increase discussed with pumps is nothing but the increase in "dynamic pressure" that the fluid would experience at if brought to rest at a stagnation point after it exist the pump?
You get both an increase in static and dynamic pressure.
 
In a centrifugal pump, the impeller increases the velocity of the fluid - kinetic energy. The fast-moving fluid then passes through the diffuser or volute, which has a larger exit area. This slows the fluid; the kinetic energy is "converted" to pressure.
 
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Understanding the cutting of said "Impeller" is a whole profession in itself. Berkley Sta right have been doing this foreva. To learn impellers, their unique physics will provide a step up in fluid dynamics as a whole...
Possibly contact someone at those Companies. They may be able to provide plethora of solid information..
Sheldon
 

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