Characteristic system curve for a two branch system

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Discussion Overview

The discussion revolves around finding the characteristic system curve for a fluid system with two branches, each containing different fluids and pumps, which converge into a single line. The inquiry includes considerations of fluid properties and system dynamics, with a focus on theoretical and practical aspects of fluid mechanics.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested
  • Homework-related

Main Points Raised

  • One participant asks how to determine the characteristic system curve for a two-branch system with different fluids and pumps.
  • Another participant emphasizes the need for a system diagram and specific fluid information, such as density, viscosity, and temperature, to provide assistance.
  • A third participant questions whether the inquiry is related to schoolwork.
  • One participant expresses interest in understanding the approach to such systems without delving into chemical reactions, suggesting a dilution instead.
  • Another participant proposes that the original poster might benefit from attempting to tackle the problem themselves, indicating that flow division in fluid networks is not trivial.
  • A later reply outlines that solving general network flow problems involves applying conservation equations and requires knowledge of pump curves and friction factors.

Areas of Agreement / Disagreement

Participants do not reach a consensus, as there are multiple competing views on how to approach the problem, and the discussion remains unresolved regarding the specifics of the system and the necessary data.

Contextual Notes

Participants note limitations in the discussion, including the need for specific fluid properties and the complexity of the system dynamics, which may depend on various assumptions and definitions.

giuseppe2127
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How can one find the characteristic system curve for a system with two different branches, each with its own fluid, T and centrifugal pump, that will than converge in a single line making a whole new fluid at a new T ? Thanks in advance.
 
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giuseppe2127 said:
How can one find the characteristic system curve for a system with two different branches, each with its own fluid, T and centrifugal pump, that will than converge in a single line making a whole new fluid at a new T ?
We need a system diagram and fluid information to even begin to help you. Fluid information includes density, viscosity, and temperature for each fluid. Do they chemically react, or merely mix? And what is T?
 
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Welcome to PF.

giuseppe2127 said:
How can one find the characteristic system curve for a system with two different branches, each with its own fluid, T and centrifugal pump, that will than converge in a single line making a whole new fluid at a new T ? Thanks in advance.
Is this question for your schoolwork?
 
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Hello, I’ve recently wanted to refresh some notions about pumping systems and started wondering how systems there aren’t as basic as a tank-line-tank would work. I found this specific example in another context, where fluids werent specified but I can look further. I was more interested on what the correct approach would be in this type of case, but I can look further for some data if it’s necessary ! I’d avoid considering a chemical reaction, maybe a dilution would be best, just to not make things more complex ! Thanks
 
It sounds to me you are looking for some basic technique on how to handle flow division in a fluid network.

If that is the case I hope you would be interested in seeing/trying how you might tackle this type of problem first? Even being basic engineering fluid mechanics, it's not a trivial procedure.

1713401624010.png


If some ##Q## was going through the pump, how much volumetric flowrate goes through line 1 and 2 respectively ##Q_1, Q_2##, given constant friction factor coefficients ##f_1,f_2##?
 
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For general network flow problems, one writes the mass, energy, and momentum conservation equations at each "node" and then solves simultaneously. You will also need equations for the pump curves, a friction factor equation, Moody chart, etc. Thermophysical properties may need to be calculated.

Steady state is simpler than transient.
 
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