Pressure in a pipeline

[Loo Kian Sing]

Is there any pressure drop across an expander for any fluid?
By referring to the "Fluid Mechanics Fundamentals and Applications" by Yunus A. Cengel and John M. Cimbala around page 353, I notice the pressure will increase after expander.
Or can I use the Darcy-Weisbach equation to calculate the pressure drop by the expander? If yes, I found that the pressure drop of an expander is greater than that of reducer? Is this true?
Appreciate if anyone answer my question.
Thank you.

 

[BigInch]

Is there any pressure drop across an expander for any fluid?
There can be. Depends on the velocity change in relation to the fluid's viscosity.
By referring to the "Fluid Mechanics Fundamentals and Applications" by Yunus A. Cengel and John M. Cimbala around page 353, I notice the pressure will increase after expander.
Velocity is reduced, so pressure can increase. Depends on the pressure changes due to velocity change in relation to the fluid's viscosity.
Or can I use the Darcy-Weisbach equation to calculate the pressure drop by the expander? If yes, I found that the pressure drop of an expander is greater than that of reducer? Is this true?
You should use pressure drop formulas for fittings and other things where changes in fluid momentum are important. Darcy-Weisbach does not include pressure changes due to momentum and velocity changes that are common in fittings.

Appreciate if anyone answer my question.
Thank you.

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[Loo Kian Sing]

Thank you for your answer.

 

[zdas04]

The Darcy-Weisbach only has one diameter in it. You get a different answer on either side of a reducer.

[bold]David Simpson, PE[/bold]
MuleShoe Engineering

In questions of science, the authority of a thousand is not worth the humble reasoning of a single individual. Galileo Galilei, Italian Physicist