Calculate pressure loss due to bends in a pipe?

AI Thread Summary
The discussion focuses on calculating pressure loss in pipes due to bends, specifically adapting methods for 90° bends to 60° and 45° bends. The resistance coefficient for a bend is given by a formula that incorporates the number of bends, friction factor, radius, and diameter. An equation derived from a fluid flow graph allows for the adjustment of resistance values for bends between 0 and 180 degrees. This equation provides an angle factor that modifies the resistance coefficient based on the bend angle. Understanding these adaptations is crucial for accurate pressure loss calculations in piping systems.
daftdave11
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how we doing i found the following information regarding finding the pressure drop in a pipe due to 90° bends. i was wondering could this be adapted for say a bend of 60° or 45°. what would be needed to change to the below information to allow this to happen?? thanking ou in advance. this would be a great help to me if i could find the solution to this.. thanks

K_B = (n-1)(.25*\pi f_T \frac{r}{d} + .5 K) + K
Where:
K_B = Resistance coefficient for overall pipe bend.
n = # of 90° bends (for a single 180° bend, n=2).
\pi = well...pi
f_T = Friction factor in turbulent zone.
r= radius of bend (in same units as d).
d= inside diameter of pipe (same unit as r).
K= Loss coefficient for a 90° bend based on table below.

90° Bend Loss Coefficients:
r/d = 1, K = 20f_T
r/d = 1.5, K = 14f_T
r/d = 2, K = 12f_T
r/d = 3, K = 12f_T
r/d = 4, K = 14f_T
r/d = 6, K = 17f_T
r/d = 8, K = 24f_T
r/d = 10, K = 30f_T
r/d = 12, K = 34f_T
r/d = 14, K = 38f_T
r/d = 16, K = 42f_T
r/d = 20, K = 50f_T
 
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daftdave11 said:
i was wondering could this be adapted for say a bend of 60° or 45°. what would be needed to change to the below information to allow this to happen?
You have the values given by the Crane paper for the total resistance of a 90 degree bend. You can multiply those resistance values by the following equation to get the resistance for all other bends between 0 and 180 degrees:
y = 1.838E-7*A3 - 8.756E-5*A2+1.748E-2*A
Where y = angle factor
A = angle of pipe bend from 0 to 180 degrees

This equation comes from a graph out of a book on fluid flow from a company I used to work for. I took the graph and did a curve fit to it. You should find that at 90 degrees the angle factor comes to 1.00 and at 180 degrees, the angle factor comes to 1.38.
 
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