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A review of the theory of Coriolis flowmeter measurement errors due to entrained particles
10th European Fluid Mechanics Conference
September 2014
© Siemens AG 2014 All rights reserved.
Page 2 Nils T. Basse / Siemens A/S, Flow Instruments
Outline
1. Background2. Bubble theory3. Measurements and model4. Outlook
SITRANS FC410
September 2014
© Siemens AG 2014 All rights reserved.
Page 3 Nils T. Basse / Siemens A/S, Flow Instruments
Background
• Sometimes flow through flowmeters will consist of mixtures, e.g. water mixed with air bubbles, oil or sand
• Mixtures will cause (i) measurement errors and (ii) damping
0 2 4 6 8 10-50
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0
10
20
Competitor Coriolis flowmeter:Mass flow rate
[%]
Erro
r [%
]
1000 [kg/h]2000 [kg/h]3000 [kg/h]4000 [kg/h]6000 [kg/h]8000 [kg/h]10000 [kg/h]12000 [kg/h]NAMUR
September 2014
© Siemens AG 2014 All rights reserved.
Page 4 Nils T. Basse / Siemens A/S, Flow Instruments
Bubble theory
• Definitions:• A fluid is either a liquid or a gas• A particle can be either a solid or a fluid (gas bubble or liquid droplet)
• Force on fluid:
• Reaction force coefficient :• Density, dynamic viscosity, St
• Total inertia reaction force on pipe:
• Mass flow rate error:•
N.T.Basse, Flow Measurement and Instrumentation Vol. 37 pp. 107-118, 2014
0 20 40 60 80 100-100
-50
0
50
100
[%]
Mea
sure
men
t erro
r [%
]
Density and mass flow rate
Air-water mixtureOil-water mixtureSand-water mixture
September 2014
© Siemens AG 2014 All rights reserved.
Page 5 Nils T. Basse / Siemens A/S, Flow Instruments
Measurements and model
• Bubble theory (phase decoupling):• Negative error
• Compressibility:• Positive error
0 2 4 6 8 10-50
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0
10
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Competitor Coriolis flowmeter:Mass flow rate
[%]
Erro
r [%
]
Model (phase decoupling and compressibility)Model (phase decoupling)Model (compressibility)
September 2014
© Siemens AG 2014 All rights reserved.
Page 6 Nils T. Basse / Siemens A/S, Flow Instruments
Outlook
• Add important effects not included:• Pressure loss• Pipe geometry• Flow pattern• Interplay between above-mentioned effects
J.Weisman, in Handbook of Fluids in Motion, pp. 409-425, 1983
September 2014
© Siemens AG 2014 All rights reserved.
Page 7 Nils T. Basse / Siemens A/S, Flow Instruments
Thank you for your attention!
Nils T. BasseSenior Research EngineerSiemens A/S, Flow Instruments
Nordborgvej 816430 Nordborg
Phone: +45 7488 2610
E-mail:[email protected]
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