examine the head loss due to viscous flow of the fluid through smooth bore pipe. Some of the governing components that will be considered are Friction factor, Reynolds number and flow rate. …Full description
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Lab report. pressure loss in pipe systems
Experiment No. 10 HEAD LOSS DUE TO PIPE FITTING
Objectives To obtain a series of readings of head loss due to pipe fitting at different flow rates and to determine the Loss coefficient for sudden contraction and sudden enlargement of pipe fitting.
Summary of theory Most pipe systems consist of more than straight pipes. The additional components like inlet, outlet bends valves and etc. add to the overall head loss of the system. The head loss that is caused by the inlets, outlets or fittings is expressed by the equation below:
h
K
u
2
2g
Where K = loss coefficient for the fitting that is involved 2 u /2g = velocity head, hv Losses can occur because of a change in pipe diameter. The loss of coefficient for a sudden contraction, K is the function of the area ratio, A2/A1. This is shown in Figure 1. The value of K changes gradually from one extreme of a sharp-edged entrance to the other extreme of no area change. The loss coefficient for a sudden enlargement is the function of area ratio of A1/A2. This is shown in Figure 2.
Procedures 1. Open fully the flow control valve V1 and the inlet isolating valve V2. Let the outlet flow control valve V4 partly open. 2. Open the isolating valve V5 for the test pipe No. 2 3. Turn on the pump and prime the line by opening air bleed valve V3. Once the water flows out from the valve, shut the valve.
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4. Insert the two manometer tubes (water manometer) into the tapping points for the sudden contraction manifold (5). 5. Close V4 and then turn the tapping valves of the two manometer tubes into open position. Open back V4 slightly to give some reading on the manometer. 6. Note down the reading on the manometer. 7. Close the drain and use a stopwatch to time the time taken to collect 5 liters of water flowing into the measuring tank. 8. Once it is done, open the drain and let the water flow into the sump tank. 9. Change the flow rate of water by regulating the outlet flow control valve V4 (See the instructor before you change the flow). 10. Again, take the manometer reading and measure the flow rate of water. 11. Obtain at least eight readings for various flow rates. 12. Turn off the pump, shut the tapping valve for sudden contraction manifold. 13. Repeat the experiment for sudden enlargement manifold (6).
Data, Observation and Results Record the results of the experiment on the result sheet provided. Calculate the flow rate (Q), velocity (u) and velocity head (hv). Q = V x 10-3 T u = 4Q πd2 hv = u2 2g Calculate the head loss (h) in mH2O. Plot the graph of h versus hv for sudden contraction (Graph 1). Plot the graph of h versus hv for sudden enlargement (graph 2). Draw a best fit line (straight line) through Graph 1 and Graph 2 and state the slope on the graphs.
Analysis and Discussion Explain about head loss in pipe (including head loss due to pipe fitting). Comment on Graph 1 and Graph 2. Calculate the experimental value for loss coefficient, K using Graph 1 (for sudden contraction) and Graph 2 (for sudden enlargement). Find the theoretical value for loss coefficient, K (use Figure 1 and Figure 2). Compare and discuss the theoretical and experimental values for K. List the possible sources of errors and safety precaution. 2
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Example of Result Table Sudden Contraction D1 = 25 mm D2 = 10 mm Volume V (Liters)
Time T (s)
Flow rate Q (m3/s)
Velocity u (m/s)
Velocity head hv (m H2O)
Head loss (H) (mm H2O)
Head loss (h) (m H2O)
Flow rate Q (m3/s)
Velocity u (m/s)
Velocity head hv (m H2O)
Head loss (H) (mm H2O)
Head loss (h) (m H2O)
Sudden Enlargement D1 = 10 mm D2 = 25 mm Volume V (Liters)
