Measuring Variable Plane Flow Rate

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Discussion Overview

The discussion revolves around measuring the volumetric flow rate through a plane with a variable area, specifically in the context of a window-type air conditioner. Participants explore methods and tools for measurement, as well as related issues in flow rate calculations.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • One participant inquires about measuring flow rate through a plane that varies in area, suggesting a focus on practical measurement techniques.
  • Another participant questions whether the flow area is being varied by an orifice valve, indicating a potential source of complexity in the measurement process.
  • A participant shares a link to a flow meter resource, possibly as a suggestion for tools that could aid in measurement.
  • There is a mention of a related discussion among fish enthusiasts regarding the accuracy of a head-loss calculator, which may parallel the challenges faced in measuring flow rates in air conditioning systems.
  • A participant expresses uncertainty about the assumptions made in the head-loss calculator, indicating that missing inputs could affect the accuracy of the results.
  • A hand calculation is presented, showing a discrepancy in expected pressure drop values, which raises questions about the assumptions used in the calculator's outputs.
  • A participant humorously acknowledges their struggles with math, indicating a desire for clarity and assistance in understanding the calculations involved.

Areas of Agreement / Disagreement

The discussion contains multiple competing views regarding the measurement of flow rates and the accuracy of related calculations. There is no consensus on the best approach or the reliability of the tools discussed.

Contextual Notes

Participants express uncertainty about the assumptions required for accurate flow rate measurements and calculations, highlighting potential limitations in the information provided by tools and resources.

plucker_08
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guys, how to measure the volumetric flow rate pass thru a plane that varies in area (small variation)
 
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Are you inferring that you have some kind of orifice valve or something varying the flow area?
 
FredGarvin said:
Are you inferring that you have some kind of orifice valve or something varying the flow area?

something varying he flow area. i would like to measure the flow rate passing thru the condenser and the evaporator of a window-type air conditioner
 
based on what you guys are asking, we have the same kind of issue, we're a network of fish enthusiasts http://www.thereeftank.com/forums/f217/head-loss-calculator-112890.html who are discussing whether or not the calculator found here is accurate or not... if anyone would like to take a look at it and help us out it would be rightly appreciated, especially since I am really, really inept when it comes to math.
 
fishfool said:
based on what you guys are asking, we have the same kind of issue, we're a network of fish enthusiasts http://www.thereeftank.com/forums/f217/head-loss-calculator-112890.html who are discussing whether or not the calculator found here is accurate or not... if anyone would like to take a look at it and help us out it would be rightly appreciated, especially since I am really, really inept when it comes to math.

Hard to tell since they don't state all of the required inputs. I presume that they make some assumptions for you and then just use the requested data to come up with their answer.

However, a quick hand calculation shows that for a 100-ft length pipe with a Blue Line HD pump (have no idea what the specs are for that pump so I'm using the output flow rate in the calc) shows that you should have about a 13.5 psi pressure drop, not 10.6 psi like they indicated. I'm assuming they are using fresh water with a viscosity of 2.3 cP and a temperature of 60 degrees F, as well as stainless steel pipe. Therefore their answer seems reasonable based on the limited information and assumptions made.

Hope that helps.

CS
 
wow thanks
well
uh
>math idiot<
least it helps me know if it's accurate ahahah :D
 

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