MECHANICS of FLUIDS LABORATORY - Mechanical Engineering

More documents

Recommendations

Info

encountered in using it is the scale factor. The scale factor will vary from fluid to fluid. 2. Diameter-ratio type–the ratio of cross sectional diameter of the tube to the diameter of the float is etched at various locations on the tube itself. Such a scale requires a calibration curve to use the meter. 3. Direct reading–the scale reading shows the actual flow rate for a specific fluid in the units indicated on the meter itself. If this type of meter is used for another kind of fluid, then a scale factor must be applied to the readings. Experimental Procedure Equipment Fluid Meters Apparatus Stopwatch The fluid meters apparatus is shown schematically in Figure 7.6. It consists of a centrifugal pump, which draws water from a sump tank, and delivers the water to the circuit containing the flow meters. For nine valve positions (the valve downstream of the pump), record the pressure differences in each manometer. For each valve position, measure the actual flow rate by diverting the flow to the volumetric measuring tank and recording the time required to fill the tank to a predetermined volume. Use the readings on the side of the tank itself. For the rotameter, record the position of the float and/or the reading of flow rate given directly on the meter. For the turbine meter, record the flow reading on the output device. Note that the venturi meter has two manometers attached to it. The “inner” manometer is used to calibrate the meter; that is, to obtain ∆h readings used in Equation 7.1. The “outer” manometer is placed such that it reads the overall pressure drop in the line due to the presence of the meter and its attachment fittings. We refer to this pressure loss as ∆H (distinctly different from ∆h). This loss is also a function of flow rate. The manometers on the turbine-type and variable area meters also give the incurred loss for each respective meter. Thus readings of ∆H vs Q ac are obtainable. In order to use these parameters to give dimensionless ratios, pressure coefficient and Reynolds number are used. The Reynolds number is given in Equation 7.2. The pressure coefficient is defined as C p = g∆H V 2 /2 (7.3) All velocities are based on actual flow rate and pipe diameter. The amount of work associated with the laboratory report is great; therefore an informal group report is required rather than individual reports. The write-up should consist of an Introduction (to include a procedure and a derivation of Equation 7.1), a Discussion and Conclusions section, and the following graphs: 1. On the same set of axes, plot Q ac vs ∆h and Q th vs ∆h with flow rate on the vertical axis for the venturi meter. 2. On the same set of axes, plot Q ac vs ∆h and Q th vs ∆h with flow rate on the vertical axis for the orifice meter. 3. Plot Q ac vs Q th for the turbine type meter. 4. Plot Q ac vs Q th for the rotameter. 5. Plot C v vs Re on a log-log grid for the venturi meter. 6. Plot C o vs Re on a log-log grid for the orifice meter. 7. Plot ∆H vs Q ac for all meters on the same set of axes with flow rate on the vertical axis. 8. Plot C p vs Re for all meters on the same set of axes (log-log grid) with C p vertical axis. Questions 1. Referring to Figure 7.2, recall that Bernoulli's equation was applied to points 1 and 2 where the pressure difference measurement is made. The theoretical equation, however, refers to the throat area for point 2 (the orifice hole diameter) which is not where the pressure measurement was made. Explain this discrepancy and how it is accounted for in the equation formulation. 2. Which meter in your opinion is the best one to use? 3. Which meter incurs the smallest pressure loss? Is this necessarily the one that should always be used? 4. Which is the most accurate meter? 5. What is the difference between precision and accuracy? 20
manometer orifice meter venturi meter volumetric measuring tank rotameter return sump tank turbine-type meter motor pump valve FIGURE 7.6. A schematic of the Fluid Meters Apparatus. (Orifice and Venturi meters: upstream diameter is 1.025 inches; throat diameter is 0.625 inches.) 21
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: actual flow rate (measured in the l
Page 23 and 24: otameter tank valve motor static pr
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

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?