Li-Chuan Chen, Marian Muste, and Larry Weber 53:071 Principles of Hydraulics Laboratory Experiment #2 Local Losses in Pipe Flows Li-Chuan Chen, Marian Muste, and Larry Weber

Objective To determine the head loss coefficient for a designated pipe fitting and its Reynolds’ number dependence.

Principle

Apparatus — Standard Pipe Geometrical characteristics for the pipeline system can be found in the appendices in the handout.

Apparatus — Streamlined Pipe Geometrical characteristics for the pipeline system can be found in the appendices in the handout.

What are we going to do? We are going to measure the upstream and downstream piezometric heads of a 90° bend for both standard and streamlined pipes.

Procedures Bleed the pipe system and tubings. Establish stabilized maximum discharge in the system. Measure the water temperature. Record the weir notch elevation. Measure the datum. Measure the piezometric heads for Tap 11, 12, 15, and 16. Measure the head on weir. Reduce the discharge and repeat Step 6 and 7 for four smaller discharges. Switch to another pipe and repeat Step 1 to 8.

Water Surface Elev. (ft) Data Sheet   Standard Pipe Streamlined Pipe Trial # 1 2 3 4 5 Water Temp. (F) Weir Notch Elev. (ft) Water Surface Elev. (ft) Datum (ft Hg) Piez. head (ft Hg) Tap 11 Tap 12 Tap 15 Tap 16

Analysis Compute velocity, piezometric, and energy heads at each pressure tap. Compute the loss coefficient (K) and Reynolds’ number (Re) for each trial. Plot K vs. Re for both standard and streamlined pipes. Compare the experiment results with empirical values and trends found in hydraulics and fluids textbooks.

Sample Result

Further Consideration Discuss the dependence of K to Re. Does it agree with the published values and trends? If the device and approach pipe are taken to be a 1:50 scale model of a prototype situation, calculate the prototype horsepower that would be required to overcome the losses in the prototype device.