Head loss in Pipes with Turbulent Flow
The objective for the lab was to determine head loss in a pipe with turbulent flow. Head loss was to be determined theoretically using Equation 1, and experimentally using Equation 2. Head loss in pipes is an expression of pressure loss through the system in terms of equivalent fluid column length (Çengel and Cimbala 2006). Equation 1 uses the Darcy-Weisbach friction factor coefficient and expresses the head loss in the system in terms of velocity, diameter and pipe length.
Equation 2 for the experimental head loss uses the change in actual pressure measurements recorded during the experiment.
f = Darcy-Weisbach friction factor
L = length
D = diameter
V = velocity
g = gravitational acceleration
P2-P1 = pressure change along the pipe
ρ = density
The procedure involved adjusting flow rate for a piping system in the fluids lab. This system loops through Ottensman Hall up to the fourth floor and back down through a system of pipes, one of which is equipped with two digital pressure gauges over a fifteen foot span.
As the flow rate was adjusted for the system, the pressure readings were recorded for six separate trials. The collected data was used to calculate velocity and solve for the Reynolds number. The friction factor was determined from the Moody chart by using the Reynolds number and the relative roughness of the pipe. Theoretical head loss was then determined by use of Equation 1 and the calculated variables. The measured head loss was calculated using the pressure readings from the gauges.
The calculated values for the theoretical and experimental head loss are given in Table 1.
Table 1 measured and theoretical head loss
Theoretical hL (ft)
Experimental hL (ft)
The results are also displayed visually in Figure 1 and 2.
Figure 1 experimental hL vs. flow rate
Figure 2 theoretical hL vs. experimental hL
Discussion of Results
The results for the theoretical and experimental head loss indicate that as the flow rate increases the difference between the predicted and actual values becomes greater. Figure 1 compares the experimental head loss to flow rate which indicates again that as flow rate increases, head loss in the system increases. Increasing flow rates would indicate that the velocity of fluid through the pipe is increasing knowing that the diameter of the pipe is constant. This increased velocity would signify more turbulent flow which would increase head loss in the system.
UWP (2008). Fluid Mechanics Laboratory Manual, CEE 3300, Fluid Mechanics, Department of Civil and Environmental Engineering, University of Wisconsin-Platteville, Platteville, WI.
Çengel, Yunus A., and Cimbala, John M. (2006). Fluid Mechanics Fundamentals And Applications, First Edition, McGraw-Hill, New York, NY.
Cite this Head loss in Pipes with Turbulent Flow
Head loss in Pipes with Turbulent Flow. (2016, Oct 04). Retrieved from https://graduateway.com/head-loss-in-pipes-with-turbulent-flow/