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Drag coefficients of bends; urgent!!

Question asked by Arnold Zeuchner on Oct 11, 2012
Latest reply on Oct 11, 2012 by Arnold Zeuchner

Hello!

 

I am writing my thesis and do not get ahead. I've got a problem with the drag coefficients of pipe bends. Flow Simulation gives me the values do not fit with my literature. It bends're not overly complicated geometry!

 

For example: I have a 90° bend (25mm internal diameter, 50mm radius). In my literature (Hofmann / Wasielewski) which is a drag coefficient of 0.14. SW gives me 0.56. I come to this value even if I calculate the resistance coefficient of the tube length of the arc of 78.5 mm (zeta = 0.24).

 

So, can me someone help me, to make sure I take the right way? I Calculate with the formula Zeta=delta p/((roh*velocity^2)/2)

 

Before I did't for this simple geometry can create right values, I need not come with anything difficult. So please help me....

 

Tanks a lot in forward

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