MECHANICS of FLUIDS LABORATORY - Mechanical Engineering

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EXPERIMENT 8 PIPE FLOW Experiments in pipe flow where the presence of frictional forces must be taken into account are useful aids in studying the behavior of traveling fluids. Fluids are usually transported through pipes from location to location by pumps. The frictional losses within the pipes cause pressure drops. These pressure drops must be known to determine pump requirements. Thus a study of pressure losses due to friction has a useful application. The study of pressure losses in pipe flow is the subject of this experiment. Pipe Flow Equipment Pipe Flow Test Rig Figure 8.1 is a schematic of the pipe flow test rig. The rig contains a sump tank which is used as a water reservoir from which a centrifugal pump discharges water to the pipe circuit. The circuit itself consists of four different diameter lines and a return line all made of drawn copper tubing. The circuit contains valves for directing and regulating the flow to make up various series and parallel piping combinations. The circuit has provision for measuring pressure loss through the use of static pressure taps (manometer board not shown in schematic). Finally, because the circuit also contains a rotameter, the measured pressure losses can be obtained as a function of flow rate. As functions of the flow rate, measure the pressure losses in inches of water for (as specified by the instructor): 1. 1 in. copper tube 5. 1 in. 90 T-joint 2. 3 /4-in. copper tube 6. 1 in. 90 elbow (ell) 3. 1 /2-in copper tube 7. 1 in. gate valve 4. 3 /8 in copper tube 8. 3 /4-in gate valve • The instructor will specify which of the pressure loss measurements are to be taken. • Open and close the appropriate valves on the apparatus to obtain the desired flow path. • Use the valve closest to the pump on its downstream side to vary the volume flow rate. • With the pump on, record the assigned pressure drops and the actual volume flow rate from the rotameter. • Using the valve closest to the pump, change the volume flow rate and again record the pressure drops and the new flow rate value. • Repeat this procedure until 9 different volume flow rates and corresponding pressure drop data have been recorded. With pressure loss data in terms of ∆h, the friction factor can be calculated with 2g∆h f = V 2 (L/D) It is customary to graph the friction factor as a function of the Reynolds number: Re = VD ν The f vs Re graph, called a Moody Diagram is traditionally drawn on a log-log grid. The graph also contains a third variable known as the roughness coefficient ε/D. For this experiment the roughness factor ε is that for drawn tubing. Where fittings are concerned, the loss incurred by the fluid is expressed in terms of a loss coefficient K. The loss coefficient for any fitting can be calculated with K = ∆ h V 2 /2g where ∆h is the pressure (or head) loss across the fitting. Values of K as a function of Q ac are to be obtained in this experiment. For the report, calculate friction factor f and graph it as a function of Reynolds number Re for items 1 through 4 above as appropriate. Compare to a Moody diagram. Also calculate the loss coefficient for items 5 through 8 above as appropriate, and determine if the loss coefficient K varies with flow rate or Reynolds number. Compare your K values to published ones. Note that gate valves can have a number of open positions. For purposes of comparison it is often convenient to use full, half or one-quarter open. 22
otameter tank valve motor static pressure tap pump FIGURE 8.1. Schematic of the pipe friction apparatus. 23
Page 1 and 2: A Manual for the MECHANICS of FLUID
Page 3 and 4: TABLE OF CONTENTS Item Page Report
Page 5 and 6: as its strong points. Suggest exten
Page 7 and 8: EXPERIMENT 1 FLUID PROPERTIES: DENS
Page 9 and 10: EXPERIMENT 2 FLUID PROPERTIES: VISC
Page 11 and 12: L level R i y zeroing weight torus
Page 13 and 14: 5. Is a low value of the standard d
Page 15 and 16: pivot balancing weight lever arm wi
Page 17 and 18: Questions 1. Can a similar procedur
Page 19 and 20: actual flow rate (measured in the l
Page 21: manometer orifice meter venturi met
Page 25 and 26: Pressure Measurement Equipment A Wi
Page 27 and 28: EXPERIMENT 10 DRAG FORCE DETERMINAT
Page 29 and 30: Experiment II For a number of wings
Page 31 and 32: axis) versus (Q 2 /b 2 h 0 3 g). De
Page 33 and 34: Therefore, Q = ∫ 0 Integration gi
Page 35 and 36: Develop a hydraulic jump in the cha
Page 37 and 38: At any upstream (of the hump) locat
Page 39 and 40: EXPERIMENT 16 MEASUREMENT OF VELOCI
Page 41 and 42: Incompressible Flow Through a Meter
Page 43 and 44: TABLE 16.1. Summary of equations fo
Page 45 and 46: placed on the torque arm to reposit
Page 47 and 48: ∆H = H 2 - H 1 = p 2 ρg + V 2 2
Page 49 and 50: Specific Speed A dimensionless grou
Page 51 and 52: 1 large orifice volume flow rate in

MECHANICS of FLUIDS LABORATORY - Mechanical Engineering

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