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This calculator is used to calculate pipe friction losses for straight piping
handling water and water with varying percentages of ethylene glycol. The
calculator uses an algorithm developed from the basic principles of fluid
mechanics. The program is based on the Darcy-Weisbach equation, the Colebrook
equation, and the Moody equation. The program is intended for use only on
straight piping. The program does not include pressure losses due to elevation
differences, or flow through fittings.
This calculator allows the user to input the fluid type, the fluid
temperature, the flow rate, the pipe size, pipe length, and pipe material. The
calculator then determines the velocity, the Reynolds number, the Moody friction
factor, the pipe friction factor (from the Colebrook equation), the pipe head
loss, and the pipe friction loss in PSI. While this calculator is intended for
use on systems handling water and water with varying percentages of ethylene
glycol, later releases will include a wider range of incompressible fluids
(liquid fuels) and compressible fluids (air).
Please note that this method works for turbulent flow situations where the
Reynolds Number is greater than 3000. If you find that your Reynolds number is
less than 3000, you should revise your input parameters (increase the flow rate
and/or reduce the pipe size).
Additional Design Criteria: If your piping is being used in an open loop
system, flow velocities should be in the range of 5 to 10 ft/sec. For closed
loop piping systems, you should use a 4 ft/sec limit for piping of 2" or
less. For larger pipe sizes, use a limit of 4 FT of head loss per 100 FT of
pipe.
References:
- Fluid Mechanics and its applications by James W Murdock, PE
Houghton Mifflin Co.
- Heating Ventilating and Air Conditioning Analysis and Design
by Faye C. McQuiston and Jerald D. Parker
John Wiley & Sons.
- Flow of Fluids Through Valves, Fittings, and Pipe
Technical Paper No. 410
The Crane Company
- ASHRAE Fundamentals 1993
The American Society of Heating Refrigerating and Air Conditioning Engineers
- www.connel.com
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