Frictional Flow in Pipes
Experiment : Friday 8.30-11.30am
Conducted In : Fluid Mechanics Lab
Abstract
The main aim of this experiment was to show how the friction factor varies with Reynolds number by manipulating the flow rate of the fluid in a pipe. The main principle used in the experiment was the Bernoulli’s equation, taking major head losses into account. These major head losses were normally due to wall friction in the pipe and viscous forces between layers in a fluid.
Generally the results obtain from the experiment do agree with the theoretical prediction and the discrepancy of the points as shown in the moody chart was relatively small. In the laminar flow and turbulent flow region where the frictional factor values are similar to the values in the moody chart. The relative roughness value obtained for the pipe was 0.0008, based on the points plotted on the moody chart.
There were a lot of sources of errors in this experiment such as systematic errors, human errors, equipment limitations and some other factors that were not taken into consideration during analysis of the data. The main errors involved human and equipment limitations, which caused the data points obtained to vary from the expected theoretical values. The factors and assumptions made were that the minor head losses were negligible, which might not have been the case. The density and viscosity values obtained from the data sheet might have also introduced error into the results.
Introduction
Theory and Principles
In this experiment, the theory and principles in used is the loss of energy and total head of fluid due to frictional resistance of real or viscous fluid. In fully developed straight pipe flow, energy loss or head losses occurs due to wall friction. These losses are usually known as the major head losses (hLmajor).
Other than major head losses, minor head losses (hLminor) too occur due to losses due
References: B. R. Munson, D. F. Young, T. H. Okiishi, Fundamentals of Fluid Mechanics, 5th Ed., 2006, John Wiley and Sons Inc. Darcy-Weisbach equation 2008. Retrieved October 3, 2008, from http://en.wikipedia.org/wiki/Darcy-Weisbach_equation Glenn Brown (2000), The History of the Darcy-Weisbach Equation. Retrieved October 4, 2008, from http://biosystems.okstate.edu/darcy/DarcyWeisbach/Darcy-WeisbachHistory.htm