Last updated: 30/09/2017, 1 min read

### Introduction

Here is an expansion of my previous post. The friction factor is calculated with 10 + 1 different methods. The equations that were used are the following (in chronological order):

- Iteration process
- Wood’s equations (1966)
- Swamee – Jain’s equations (1976)
- Churchill’s equations (1977)
- Chen’s equation (1979)
- Round’s equation (1980)
- Zigrang and Sylvester’s equation (1982)
- Haaland’s equation (1983)
- Serghides’ equations (1984)
- Manadili’s equation (1997)
- Goudar – Sonnad’s equations (2008)

In the file, you will see in detail all the above equations, as well as their limitations (regarding Reynolds number and roughness to diameter ratio). The workbook also compares the results of these methods with the results of iteration process and gives as an output the method that gives the best results. So, if you want to find the friction factor in a pipe try to experiment with this file.

### How to use it

In the first sheet (named “Solutions”) fill all the green cells and press the “Solve Equation” button. If the flow in the pipe is turbulent, the sheet will automatically calculate the friction factor with the 11 methods that presented above. If you press one of the buttons named “Roughness,” “Diameter,” “Velocity” or “Viscosity” you will be transferred to the corresponding sheet. There you can “play” (loop calculation) with the relevant parameter and see how the results of 11 methods are affected by the parameter’s change. Furthermore, each sheet includes a chart which depicts the results of your loops.

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**Downloads**

This file can be opened with Excel 2007 or newer. For best results, go to File -> Options -> Formulas tab and put Maximum Iteration = 30,000 (max value is 32,767) and Maximum Change = 0.00001 (or even smaller).

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