WRIGHT STATE UNIVERSITY



Wright State University Fall 2004

Department of Mechanical and Materials Engineering

ME 317: FLUID DYNAMICS LABORATORY

Experiment 5: Fluid Circuits Demonstrator

Objective: The objective of this experiment is to study the effects of friction on the pressure drop when water flows through pipes made of different materials.

References: Fox, McDonald and Pritchard, Introduction to Fluid Mechanics, 6th edn., Section 8-7: Calculation of Head Loss.

Preparation: Read the reference material and these instructions, then perform the experiment with your assigned group.

Equipment Needed: Flow circuit in Room 122, manometer bank.

Experimental Procedure: The flow circuit consists of a recirculation tank, a centrifugal pump, a ball valve, a sharp-edged orifice flow meter, three lengths of ½ inch (nominal) pipe, and a bank of manometers. The centrifugal pump forces the water from the recirculation tank through the valve and past the orifice plate flow meter, which was calibrated in Lab 4. Downstream from the flow meter is a length of ½ inch copper pipe, a length of ½ inch stainless steel pipe, and a length of ½ inch PVC pipe, which all have pressure taps to determine the pressure drops. The pressure drop within each length of pipe is read by the bank of manometers in inches of water. The mass flow rate of water through the system is set using the ball valve. The length between the pressure taps for the three pipes are all L = 24 inches. The inside diameter of the ½ inch copper pipe is Dc = 0.545 inches, the inside diameter of the ½ inch stainless steel pipe is Dss = 0.674 inches, and the inside diameter of the ½ inch PVC pipe is DPVC = 0.546 inches.

1. Measurements

a. Close the ball valve.

b. Turn the centrifugal pump on by plugging the extension cord into the wall.

c. Slowly move the ball valve until the pressure difference between the high-pressure side and the low-pressure side of the manometer for the flow meter is close to the first value shown on the worksheet provided.

d. Record the upstream and downstream pressures for the flow meter and the three lengths of pipe.

e. Adjust the valve such that the pressure difference for the flow meter is close to the next setting on the worksheet provided.

f. Repeat steps (d) and (e) for each setting.

g. Turn the pump off.

Wright State University Fall 2004

Department of Mechanical and Materials Engineering

ME 317: FLUID DYNAMICS LABORATORY

Experiment 5: Fluid Circuits Demonstrator

2. Data Reduction

a. The laboratory teaching assistant will obtain a copy of the experimental data taken by each lab section, which will be forwarded in electronic form to me. Download the data from all of the lab sections for data reduction at my website:

b. Create an Excel spreadsheet to calculate following: the predicted mass flow rate based on the average discharge coefficient of the orifice flow meter, the Reynolds number for each length of pipe, and the Darcy friction factor for each length of pipe (f). Remember that the Reynolds number for each length of pipe must be calculated separately due to the fact that the inside diameters of the three pipes are all different.

c. Create a graph by plotting the Darcy friction factor for the three pipe sections on the y-axis versus the Reynolds number on the x-axis. Also show the plot of the Blasius correlation for turbulent flow in smooth pipes:

[pic]

Report: Prepare a brief report in the usual format. The above-mentioned Excel spreadsheet and the graphs are to be included. The Darcy friction factor is given by

[pic]

Answer the following questions:

1. Is the friction factor predicted well by the analysis? Why or why not?

2. Discuss some issues in which this lab could be redesigned in order to achieve better results.

Wright State University Fall 2004

Department of Mechanical and Materials Engineering

ME 317: FLUID DYNAMICS LABORATORY

Experiment 5: Fluid Circuits Demonstrator Data Sheet

|Pressure (inches of H2O) |

| |PVC |Stainless Steel |Copper |Flow Meter |

Approximate Manometer Delta P |Down |Up |Down |Up |Down |Up |Down |Up | |2.5 | | | | | | | | | |5.0 | | | | | | | | | |7.5 | | | | | | | | | |10.0 | | | | | | | | | |12.5 | | | | | | | | | |15.0 | | | | | | | | | |17.5 | | | | | | | | | |20.0 | | | | | | | | | |22.5 | | | | | | | | | |25.0 | | | | | | | | | |

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