Reynolds 10^5 & Hazen-Williams Friction Model: Is There a Problem?

AI Thread Summary
The Hazen-Williams friction model may fail in hydraulic circuits, particularly at high Reynolds numbers around 10^5, leading to unrealistic results like infinite volumetric rates. This model is empirical and lacks a solid physical basis, with roughness constants derived from conditions that may not apply to all scenarios. Users have noted the need to switch between friction models due to the Hazen-Williams model's longer computational times and unreliable outputs. There is a suggestion to compare the Hazen-Williams model with the Darcy-Weisbach model to assess performance under different conditions. Further investigation into the applicability of the Hazen-Williams formula is necessary to understand its limitations.
Clausius2
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Is there some reason for Hazen-Williams friction model to failure in a hydraulic circuit?.

I have simulated an hydraulic system in a commercial code, and this model is the unique which gives stupid results like infinite volumetric rates. The Reynolds is about 10^5.
 
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My reference as well as the website here (http://www.piping-toolbox.com/6_797.html) show that you are right on the edge of R_e for using Hazen-Williams. Also, are you possibly outside the realm of this:
Note that the Hazen-Williams formula is empirical and lacks physical basis. Be aware that the roughness constants are based on "normal" condition with approximately 1 m/s (3 ft/sec).

I guess after we discount those two notions, the model will have to go under the microscope. Is there any way to compare your model to Darcy?
 
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FredGarvin said:
My reference as well as the website here (http://www.piping-toolbox.com/6_797.html) show that you are right on the edge of R_e for using Hazen-Williams. Also, are you possibly outside the realm of this:


I guess after we discount those two notions, the model will have to go under the microscope. Is there any way to compare your model to Darcy?

It doesn't help too much, but thanks anyway .

The problem is I have to switch between friction models when calculating an hydraulic installation, but this model is the unique which spends the longer computational time and gives unbelievable results. I was searching for same sort of conditions in which this formula is applicable, but I haven't found nothing interesting for justifying this fact.
 
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