1. Volume Flow Measurements

2. Obstruction Meters u Orifice Meters u Venturi Meters u Flow Nozzles

3. Flow through a Nozzle Basic Equations: a.) Continuity: mass in = mass out b.) Bernoulli’s Eqn. Total pressure is constant throughout

4. Flow through a Nozzle

6. PP

7. Y = Compressibility Factor =1 for incompressible flow or when  P<< P abs C=Discharge Coefficient =f(Re) and nature of specific flow meter PP Flow through a Nozzle P

8. Flow through a Venturi Meter In a venturi, 0.95 < C < 0.98 Advantage: Pressure recovery Uses little power

9. Flow through a Venturi Meter C ReRe 2 x 10 5 0.98 Based upon the conditions in the pipe approaching the meter

10. Back to the Nozzle P1P1 P2P2 P P1P1 P2P2

11. Shorter and cheaper than venturi But larger pressure drop. Thus, more power lost in operating. The Nozzle Flowmeter C 0.86 0.98 10 3 10 5 ReRe

12. Flow Through an Orifice Meter

13. P1P1 P2P2 P P1 d D

14. Flow Through an Orifice Meter -Cheapest and Simplest -But biggest pressure drop and power lost (C~0.6 - 0.7) -Side Note: Pressure drop caused by friction and turbulence of shear layer downstream of vena contracta 0.6 0.85  =d/D 0.10.8 ReRe 100k 5000 10k

15. Elbow Flowmeter

16. Laminar Flowmeter

17. Pitot-Static Tubes

18. Rotameter, variable-area-flowmeter u Force balance u Drag Force u Gravity u Buoyancy u (usually negligible) Derived on next slide

19. For a fixed x-position, A is fixed. Then Rotameter Equations

20. Turbine Flow Meters

21. Vortex meters operate on the principle that when a non-streamlined object is placed in the middle of a flow stream, vortices are shed alternately downstream of the object. The frequency of the vortex shedding is directly proportional to the velocity of the liquid flowing in the pipeline.

22. Magnetic flowmeter

23. Based upon Faraday’s Law The fluid is the conductor, must be electrically conductive. E=BDVx10 -8 E=voltage, volts B=magnetic flux density, gauss D= length of the conductor, cm V=velocity of the conductor, cm/sec Magnetic flowmeter

24. Magnetic Flow Meter

25. Coriolis Mass Flow Meter

26. Vibrating Flow Tube Fluid Force is Reacting to Vibration of Flow Tube End View of Flow Tube Showing Twist Twist Angle Flow Force Flow Force Flow

27. Coriolis Mass Flow Meter

28. Positive Displacement Meters