Measurements in Fluid Mechanics 058:180 (ME:5180) Time

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Measurements in Fluid Mechanics058180
(ME5180)Time Location 230P - 320P MWF 3315
SCOffice Hours 400P 500P MWF 223B-5 HL

• Instructor Lichuan Gui
• lichuan-gui_at_uiowa.edu
• Phone [phone] (Lab), 319-400-5985 (Cell)
  http//lcgui.net

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Lecture 14. Flow rate measurement
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Flow rate measurement
Bulk flow rate
- the amount of fluid that pass through a certain
cross section of a pipe, duct, channel, or
other conduit per unit time.
- not concerned with local velocity variations
across cross-section
- not concerned with short-time (turbulent)
fluctuations
Volume flow rate Q usually used for liquids
or low-speed gasses
Direct methods for flow rate measurement
- positive-displacement flow meters
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Flow rate measurement
Positive-displacement (PD) flow meters
- devices that isolate fixed volumes of fluid
flowing into their inlet in sealed compartments
and then discharge them to the outlet.
- volume flow rate calculated from the size and
number of compartments and the repetition rate
- some PD meters may passively receive power from
flowing fluid to operate.
- some PD meters (metering pumps) are driven by
external power source to create fluid motion.
- a great variety of designs of PD meters,
classified as rotary, reciprocating, or nutating
- problems of PD flow meters leakage and
pressure loss
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Flow rate measurement
Nutating disk meters
- a disk rotating in a nutating fashion in a dual
conical housing
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Flow rate measurement
Reciprocating -piston meters
- plunger or piston driven by wobble plate (or
cam)
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Flow rate measurement
Rotary-piston (oscillating piston ) flow meters
- a cylindrical drum mounted eccentrically inside
a cylindrical housing
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Flow rate measurement
Rotary-vane flow meters
- flat vanes inserted into matching slots around
the perimeter of a cylindrical drum located
eccentrically within the housing
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Flow rate measurement
Rotor meters
Oval Gear Meters
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Flow rate measurement
Rotor meters
Gear flow meters
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Flow rate measurement
Rotor meters
Helical gear flow meter
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Flow rate measurement
Roots-type flow meters
- a particular design of a lobe meter
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Flow rate measurement
Diaphragm-type meters
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Flow rate measurement
Liquid-sealed flow meters
- wet gas meters liquid provides sealing action
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Flow rate measurement
Restriction (or obstruction) flow meters
Venturi tubes (a b)
Flow nozzles (d)
Dall tubes (c)
Orifice-plate (e)
- Circular tube of diameter D
 
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Flow rate measurement
Open-channel flow measurement
Weirs
Venturi flumes
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Homework
- Read textbook 9.1-9.4 on page 208 - 212

• Questions and Problems 1 on page 219

- Due on 09/28
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Try to write a Matlab program

• To cut a 6464-pixel image sample from a
  12801024-pixel image at i200, j400

6464-pixel image sample
clear A1imread('A001_1.bmp') nx nysize(A1)
I200 J400 M64 N64 for i1M for
j1N iiiI-int16(M/2)
jjjJ-int16(N/2)
G1(i,j)A1(ii,jj) end end imwrite(G1,'G1.bmp'
,'bmp')
http//lcgui.net/ui-lecture2012/hw/00/A001_1.BMP

• To cut a 6464-pixel image sample from a
  12801024-pixel image at X400.6, Y200.3