Concentrated pressure drop in tube having 90 round bend

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Discussion Overview

The discussion revolves around calculating the concentrated pressure drop in tubes with 90-degree and 180-degree round bends. Participants explore the relevant equations and factors involved in determining the pressure drop, specifically focusing on the coefficient for concentrated pressure drop.

Discussion Character

  • Technical explanation
  • Homework-related

Main Points Raised

  • One participant presents an equation for calculating concentrated pressure drop, questioning how to determine the specific coefficient for concentrated pressure drop (b).
  • Another participant suggests referring to Crane Technical Paper No. 410 as a source for these coefficients and offers to provide approximate values if the line size and flow rate are shared.
  • A participant provides specific details about their system, including mass flow rate, tube length, and dimensions, indicating a need for assistance in calculating the pressure drop.
  • One participant mentions a resource link for further calculations and emphasizes the importance of being able to perform hand calculations rather than relying solely on computer tools.

Areas of Agreement / Disagreement

Participants generally agree on the need for the coefficient b to calculate the pressure drop, but there is no consensus on how to determine it without access to specific resources.

Contextual Notes

Participants have not resolved how to determine the coefficient b, and there may be limitations in the provided information regarding flow conditions and assumptions about fluid behavior in bends.

Who May Find This Useful

This discussion may be useful for individuals interested in fluid dynamics, particularly those dealing with pressure drop calculations in piping systems with bends.

alshourbagy
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Hi
i want to calculate the concentrated pressure drop in a tube having 90 round bend and other one having 180 round bend.
The equation that i know is:
dP (concentrated) = 1/2 * b*r*v^2
where:
b=specific coefficient for concentrated pressure drop
r = liquid density (kg/m³)
v = average speed of the fluid inside the tube (m/s)

My problem is how to determine b?

thanks
Moh
 
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One of the best sources of these factors is the Crane Technical Paper No. 410. If you don't have access to this book, let me know your line size and flow rate I can give you some approximate values.
 
many thanks for your kind help...unfortunately I have no access.
here is the info...
1st line:
water mass flow rate= 1 l/m
tube Length=36m
internal diameter= 12mm
external diameter= 15mm

2nd line is the same except for the length that is 41m.
The tube will be bending like in the image attached.
 

Attachments

My Crane TP 410 book is at work, but start with this link

http://www.pressure-drop.com/

Run a few cases. Then make sure you can do this by hand calculation and not depend on the computer !
 
Thanks a lot...i will do it
 

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