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

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SUMMARY

The Hazen-Williams friction model exhibits significant limitations when applied to hydraulic circuits, particularly at a Reynolds number of 10^5. Users report instances of unrealistic volumetric flow rates, indicating the model's empirical nature and lack of physical basis. The roughness constants used in the model are based on conditions around 1 m/s (3 ft/sec), which may not be applicable in all scenarios. A comparison with the Darcy-Weisbach model is suggested to evaluate performance under varying conditions.

PREREQUISITES
  • Understanding of hydraulic systems and fluid dynamics
  • Familiarity with the Hazen-Williams friction model
  • Knowledge of the Darcy-Weisbach equation
  • Experience with computational fluid dynamics (CFD) software
NEXT STEPS
  • Research the limitations of the Hazen-Williams friction model in high Reynolds number applications
  • Learn about the Darcy-Weisbach equation and its advantages over Hazen-Williams
  • Explore computational fluid dynamics (CFD) tools for hydraulic simulations
  • Investigate empirical correlations for friction factor in turbulent flow
USEFUL FOR

Engineers, hydraulic system designers, and researchers involved in fluid dynamics and hydraulic modeling will benefit from this discussion.

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 [tex]R_e[/tex] 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?
 
Last edited:
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 [tex]R_e[/tex] 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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