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How to use it.
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
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