# Concentrated pressure drop in tube having 90 round bend

1. Aug 19, 2011

### alshourbagy

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

2. Aug 19, 2011

### edgepflow

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.

3. Aug 20, 2011

### alshourbagy

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.

#### Attached Files:

• ###### tube bending.bmp
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4. Aug 20, 2011