The Equation for Volumetric Flow Rate?

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Discussion Overview

The discussion revolves around the calculation of volumetric flow rate (VFR) in fluid dynamics, specifically focusing on the equations used to determine VFR and their application in a practical example involving water flow through a pipe. The scope includes theoretical understanding and practical application.

Discussion Character

  • Exploratory
  • Technical explanation
  • Mathematical reasoning

Main Points Raised

  • One participant expresses uncertainty about which equations to use for calculating volumetric flow rate, presenting two equations: Q = Velocity * Area and Q = Volume / Time.
  • Another participant provides a practical example involving a pipe with a specified diameter and water velocity, asking for a calculation of the volume collected in a minute.
  • A third participant performs the calculation using the first equation, detailing the steps taken to find the volumetric flow rate and converting the result to liters.
  • Subsequent replies affirm the correctness of the calculations and emphasize the importance of using the first equation as the primary method for determining volumetric flow rate.
  • There is a mention that the second equation serves more as a clarification of units rather than a primary calculation method.

Areas of Agreement / Disagreement

Participants generally agree on the use of the first equation (Q = Velocity * Area) as the primary method for calculating volumetric flow rate, while the second equation is viewed as a clarification of terminology. However, there is no explicit consensus on the necessity of using both equations simultaneously.

Contextual Notes

Some participants highlight the importance of unit consistency in calculations, but there are no explicit discussions about potential limitations or assumptions in the equations presented.

Who May Find This Useful

This discussion may be useful for individuals seeking to understand the principles of fluid dynamics, particularly in calculating volumetric flow rates in practical scenarios.

skoopfadj
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I'm not sure how to clearly express my query, so I'll round up the gist of it. I understand that this is an entry level question.

I was told that, in order to calculate Volume Flow Rate (VFR), I would use these equations:

* Q = Velocity * Area [EQUATION 1]
* Q = Volume / Time [EQUATION 2]
Units: m^3 / s

Questions:
^Do I use both equations? Are they both deemed correct or only one and which one?
^Can you give an example problem or scenario in which I would use the appropriate equation?
 
Last edited:
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Example: You have a pipe with a diameter of 400mm. Water flows through the pipe at a velocity of 1 m/s. Determine how many liters you would have collected in a minute?

Use your equation as you mentioned and come up with a solution, don't et sidetracked by the units, do the first principals correctly...
 
@WillemBouwer Correct?

Prompt: A pipe has a diameter of .4 meters. Water flows through the pipe at 1 m/s. Determine how many liters (water) you would have collected in a minute?

Radius: .2 meters (m)
Vinitial: 1 m/s
Volume: ?
Time: 60 seconds

Q = V * A
Q = 1 * (∏(.22))
Q = 0 .1256637061 m3/s

--> Q = V / T
.1256637061 = V / 60
Volume = 7.539822369 m3 or
7.539822369 * 1000 = 7,539.822369 L

1 m3 = 1000 Liters (L)
 
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There you go... Using the equation right...
The second equation is just an explaining of the units or terminology, Volume flowrate is exactly that, m^3/s, volume over time. But the first equation is the most commonly used.

However when you get a question, make sure to answer the question as asked with units, always remember your units... But you understand the principal! Cool beans...

So, how many liters per minute?
 
It should be on there.
7,539.822369 L ?
Thank you very much Mr. Bouwer. (:
 
No problem. I see it shows now, didn't the previous one, haha. good job though, correct answer...
 

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