Calculator

Fluid Flow Calculator
by Michael J. Rocchetti PE
Mechanical Engineer

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 you 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. This calculator is intended for use on systems handling water and water with varying percentages of ethylene glycol.

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

 Fluid Temp F: 40F 60F 80F 100F 120F 140F 160F 180F 200F 220F 240F Fluid Type is Water. Select a % of ethylene glycol 0 10 20 30 40 50 flow rate GPM: Pipe Material: Copper, type L Steel, Schedule 40 Pipe Size: 1 1-1/4 1-1/2 2 2-1/2 3 3-1/2 4 5 6 8 10 12 14 16 18 20 pipe length ft: *