![Roughness of copper pipe](https://kumkoniak.com/52.jpg)
The bottom curve on a Moody chart shows the relationship between friction factor and Reynolds number for a smooth pipe. See also Maximum Shear Stress Theory Explained Moody Diagram for Smooth Pipe Lewis Moody solved the Colebrook equation for many different combinations of Reynolds number and roughness height and plotted them on a chart. The Moody diagram was created in the early 1940’s before the use of calculators and computers became commonplace. However, it’s a complex equation to solve. The Colebrook Equation is an implicit equation that relates the Darcy friction factor to the Reynolds number, diameter, and pipe roughness, much like the Moody chart. In these instances, it is worthwhile to conduct a sensitivity analysis to see how behavior changes with variations in roughness height and friction factor. However, when it’s impossible or impractical to measure roughness height directly, estimates are necessary.
![roughness of copper pipe roughness of copper pipe](https://media.cheggcdn.com/media/5e4/5e4fabd4-b72a-41c8-85d6-a0be6a58d914/php9eqgGk.png)
The only way to obtain a truly accurate roughness height is to measure it with a tool like a profilometer. Values of roughness height found in tables are estimates at best and can vary widely for the same material from different sources. The most significant source of error, besides reading the chart incorrectly, comes from the roughness height. pdf file of a Moody Diagram by clicking on the image below:Ī Moody chart is only as accurate as the exactness of the inputs. In this example, the friction factor is approximately 0.02. If the Reynolds number is 8×10 5, then it intersects the curve at (2).įinally, estimate the friction factor by looking horizontally from the intersection between relative roughness and Reynolds number to the left axis (3). Next, locate the Reynolds number at the bottom of the chart and find where the Reynolds number intersects the curve from above. See also Swamee-Jain Equation for Friction Factor If the relative roughness of a pipe is 0.001, find the corresponding curve from the right side of the Moody diagram (1). Next, calculate the Reynolds number for the fluid flow. ε is the roughness height of the internal walls of the pipe and is published in many tables.
![roughness of copper pipe roughness of copper pipe](https://neutrium.net/images/fluid-flow/pipe-roughness.png)
To read a Moody Chart, first calculate the relative roughness of the pipe, ε/D. Friction factor is an empirical term that can be determined by solving complex formulas or by simply looking it up on a Moody chart.Īlthough using a Moody chart is easier to use for one-off calculations, it is not always useful for repetitive calculations or automation of pressure loss calculations due to the need to interpret values from a chart. One of the terms in the equation is the Darcy friction factor. The Darcy Weisbach equation is commonly used for calculating pressure drop in a pipe due to friction, otherwise known as major losses. Moody Diagram and the Colebrook Equation.
![Roughness of copper pipe](https://kumkoniak.com/52.jpg)