flow

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Author:
george123
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164678
Filename:
flow
Updated:
2012-08-01 07:27:01
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flow
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flow
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  1. Whatisvolumetricflowrateandwhataresomeofthetypicalunitsofmeasure?
    •  is the volume of fluid which passes through a given surface per unit time. The SI unit is m3 s-1 
    • Metres per sec
  2. Whatismassflowrateandwhataresomeofthetypicalunitsofmeasure?
    • Mass that passes through a point per time period
    • Kg per min

     The SI units are kg s-1

     = mass flow rate,
  3.  How does mass flow rate differ from volumetric flow rate?
    Volume flow is used to speeds.  Mass flow ignores the concept of volume and deals with molecules flowing per unit time. 
  4. Whenwoulditbeimportanttoknowmassflowrateovervolumetricflowrate?
    As this is how you charge a customer
  5. Whatarethethreemajortypesoffluidthatweencounterinaprocess?
    • Gases
    • Liquids
    • Liquids with sediments
  6. What is velocity profile when related to flow in a pipe?
  7. Layers
  8. What is the Reynolds Number and who discovered it?
    • Osborne Reynolds
    • The number used to Define the type of flow in a process
  9.  WhatarethefactorsthataffecttheReynoldsNumber?
    Density and velocity
  10. 9. What is the unit of the Reynolds Number?
    Re
  11. What name is used to describe the flow with a Reynolds Number less than 2000 and what would its velocity profile look like?
    • Laminar
    • That it is flowing in layers

    • It looks like that pipe diagram that looks like a meddle podium
    • The centre is ahead and each side steps down to the edge
  12. . What name is used to describe the flow with a Reynolds Number greater than 4000 and what would its velocity profile look like?
    • Turbulant flow
    • The diagram that of the semi circle but at the top it is a tiny squiggly line
  13. What name is used to describe the flow with a Reynolds Number greater than 10000 and what would its velocity profile look like?
    • Chaotic
    • Some backwards some forwards
    • Sort of swirling around
  14. .What name is used to describe the flow between 2000 and 4000 is said to be?
    Transitional
  15. 14. Why is it necessary to know the type of flow in relation to flow measurement?
    As this will deceide what type of flow measurement is used as there are many types for different applications
  16.  If a pump takes 2 hours to fill a 5000 litre tank. What is the flow rate in cubic meters per hour? What is the flow rate in litres per minute?
    2 hours to fill a 5000 litre tank

    5000^2=2500l/h

    5000^120=2 hours to fill a 5000 litre tank

    5000^2=2500l/h

    5000^120=41l/min
  17. A 100 mm pipe has a flow rate of 150 litres per minute what is the velocity of the liquid? IftheSGoftheliquidis1.2,whatisthemassflowrate?
    • 1. Draw diagram ALWAYS
    • 2. Convert all to metres
    • 100mm = 0.01m
    • 150L/min = .15m^/min
    • 3. Cross sectional area
    • Pie x radius squared
    • 3.1416 x .005 = 0.01571
    • 4. Volume = csa x length
    • Length = volume / csa
    • .15 / .01571 = 9.45 m/ min

    • Mass = volume = csa x length
    • .15m2 x .01m = .00015m3 = 1.5L =1.5L / min
    • 1.5 x1.2 = 1.8L/min with this material
  18. How long do you need to run the pump if you require 2500 litres of product and the pump flow rate is 20 litres per minute?
    2500/20= 125minutes
  19. What effect do pipe elbows, valves and other disturbances have on the flow profil
    Of where the flow meter is located and installed 
  20.  What is the general rule for locating flow meters next to pipe elbows and valves?
    • 10 diameters before
    • 5 diameters after 
  21. 20. Why do some flow meters need to have square root extraction?
    to make the reading linear
  22. 21. Describe how you would use a pressure transmitter to measure flow?
    • A metre using  Bernoulli's principle
    • As the speed of a fluid increases the pressure within the fluid decreases 
  23. . What are different designs of orifice plate? What fluids are they used for?
    • Concentric. Centre hole
    • Eccentric. Bottom
    • Segmental. Hole at top
    • Wether there are air bubbles, liquids with Bernoulli'ssolids, or just plain fluids 
    • Orifice plate like a multimeter 
    • It measures pressure on both ends of a resistor, simar to ohms law
  24. 23. What are the main disadvantages of orifice plates?
    wear and will drift over time. 
  25. How is a venturi tube used to measure flow and what type of sensor is used?
    forces the fluid into a small space like a plane wing

     A DP transducer is used on both ends, S the speed of the fluid increases te pressure within the fluid decreases 
  26. 25. What is a flow nozzle?
    • flow nozzle is a compromise between the orifice plate and the venture tube.
    • It's a half half mx between the 2
  27. 26. What is a pitot tube?
    A pitot tube is a pressure measurement instrument used to measure fluid flow velocity
  28. 27. Why is an annubar better than a pitot tube?
    The annubar takes multiple samples across a section of a pipe or duct
  29. 28. What type of flow does a rotating van and a nutating disc meter measure?
    Water
  30. . A turbine flow meter is not accurate when the flow is fully turbulent. What can be fitted to improve performance?
    Use flow conditioners
  31. 30. How does a Magflow meter work?
    A magnetic field is applied a the metering tube, which results in a potential difference proportional where producing electromagnetic induction. 
  32. 31. Can you use a Magflow meter to measure the flow of distilled water?
    • Yes 
    • Water is conductive
  33. 32. What are the precautions to be taken when installing a Magflow meter?
    Coriolis Flow Meter
  34. As an object moves from the centre to the circumference of a rotating disc it is subjected to an inertia that will tend to move it from its attempt to move in a straight direction. What type of flow meter uses this effect?
    Coriolis Flow Meter
  35. 34. Can the coriolis flow meter measure mass flow?
    uses bluff alternating vortices, like a flag pole.
  36. 35. What is the principle that a vortex meter uses?
    Definatly yes. Good for it
  37. 36. Can a vortex meter measure low flow rates?
    uses bluff alternating vortices, like a flag pole.
  38.  Describe how ultra sonic flow meters measure flow?
    An ultrasonic flow meter is a type of flow meter that measures the velocity of a liquid or gas (fluid) by using the principle of ultrasound. Using ultrasonic transducers, the flow meter can measure the average velocity along the path of an emitted beam of ultrasound, by averaging the difference in measured transit time between the pulses of ultrasound propagating into and against the direction of the flow. Ultrasonic flow meters are affected by the temperature, density and viscosity of the flowing medium. They are inexpensive to use and maintain because they do not use moving parts, unlike mechanical flow meters.
  39. 38. How does a flow meter that measures temperature work?
    The movement of a fluid passed an object can cause cooling.
  40. . Gases can be compressed. How does this affect its flow measurement?
    not sure
  41. 40. Describe several methods of measuring mass flow in gases?
    • Boyles Law states that If the pressure of a gas increases and the temperature remains the same then the volume will decrease.
    • Gay Lussac's Law States that if gas temperature increases and the pressure remains the same then the volume will increase.

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