basics vortex

ABBBasics Vortex.ppt 02/01-Thn

Basics on Vortex flowmetersPrinciple

AdvantagesLimitations

Basics Vortex.ppt 02/01-Thn

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Karman Vortex street

Bluff BodyPiezo-Sensor

d

V

f

D


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Re

St

Piezo-Sensor

Q= Flow, K= Faktor of calibration [1/m³]

D linear flow range

Strouhal No. as a function of the Reynold No.

f = shedding frequencySt = Strouhal No.v = flow velocityd = bluff body widthν = Kinematic viscosityRe = Reynold numberD = Meter size

Bluff Body

dv*St

f =υ

D*vRe =

[m�/h] K3600*f

Q =

Principle of Operation


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Example of a real Kármán Vortex Street

n A phenomenon from the textbook of Fluid Mechanics:n The wind flows around an obstruction -such as the

Island Guadalupe - located at the Pacific cost of Mexico and causes in lee, the side away from the wind, a braid like "Kárman Vortex Street" more than 250 kilometers in length. It is only visible through the clouds brought by the wind.

n Theodore von Kármán born in Budapest, Hungary taught in the twentieth at the Technical University,Aachen, Germany and investigated primarilyturbulences associated with aircraft surfaces. He emigrated 1930 to the United States and became one of the cofounders of the world-famous "Jet Propulsion Laboratory" in Pasadena, California.

Island Guadalupe


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Island Socorro

Also on the leeward side of Socorro- an enchanted Mexican island of the Revilla-Gigedo archipelago -1300 kilometers southeast ofGuadalupe, a small approximately 70 kilometer long variant of theKárman flow became visible. The inhabited island is situated on the extension of the Central American fault line, whose tectonic activities continually trigger earth-quakes and volcanic eruptions.On Socorro the 1130 meter high volcano Eveman is proof of the vitality of this system.

Kármán Vortex Street


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Features of Vortex-Flowmeters

n Ideal for the measurement of low viscous fluids, gases and steam

nThe measurement is independent of:n conductivity

n In the valid measuring range of the diameter the measurement of the actual flow is independent of:n densityn temperaturen viscosityn pressure

nextensive independence of:n deposits and pollution


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Reliable measurement

n Also in Spite of Dirt and Deposits


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Advantages of Vortex measurement

nUniversal method of measurement for fluids, gas and steamn no moving parts in the measuring tube, no wear, no maintenancen rugged and simple constructed primaryn high accuracy, e.g. 0,75 % of rate at liquids

1 % of rate at gasn large measuring span, e.g. 1 : 20n very good price-effectiveness ration lowest installation costs by use of 2-Wire technologyn Ex-design for hazardous area Zone 1 and 2n different process connectionsn CIP (Cleaning in place) n up to size DN 200 lower in price than orifice platen high vibrationimmunity up to 1 g (acc. to NAMUR cond.)


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"water hammer effect" at steam measurement


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n Vortexn High accuracy: 1% of raten Up to 5 x larger measuring spann Easy installation and start-up n Outputs: analog and scaled pulsen Flow rate and totalization via

display n Linear flow measurement

n Maintenance freen To DN 200 lower in pricen Medium temperature < 400°C

Vortex Flowmeters compared to orifice plate

n Orificen Accuracy approx. 2% of rangen Typical span 1 : 4n DP-transmitter, piping, valves etc.n Involved start-up, higher installation

costn Analog output onlyn No flow rate and totalization via

display n Not maintenance free installationn Only from DN 200 lower in pricen Available for high medium temp.

application > 400 °C


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Limits of vortex flowmeasurement

nonly fluids with a viscosity of ≤ 7,5 mPas can be measured precisely

nstatic overpressure is required to avoid cavitation when using fluids

ndeposits can cause measuring errors

n in-/outlet sections piping of approx. 15 x DN/5 x DN required

nno 2 phase liquids

nMinimum pressure (5 barg) at gases with low density e.g. H² needed (required density 0,5 kg/m³)

nDiameter-range flange: DN15 to DN300

nDiameter-range wafer: DN15 to DN150


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Branch of industry Medium

Metal industry

petrochemical raw materials, petrol, ethylene, steam, etc.Petrochemistry

Chemistry

compressed air, steam

steam, condensate, natural gas

Plant engineering

Food industry

Pharmaceutical indust.

Paper industry

acids, solvents, sludge water, gases, steam, etc.

CO2, sludge water, steam

compressed air, steam

coolant circuit, air, protection gases

Power plants

diionized water

Fields of application for Vortex-flowmeters


ABB320

330

340

350

360

370

380

0 50 100 150 200 250 300 350 400 450

Sensorfrequency F[Hz]

K-f

ac

tor

1/m Q = 100 %

Q = 26 % Q = 50 %Q = 16 %

Q = 6 %

DN 150 / 6”ANSI / Gas

[m�/h] K3600f

Q∗

=

Example Standard calibration 5 points

basics vortex

Documents

sludge water

high accuracy

abbbasics

orifice plate

dn 200 lower

basics vortex

vortex

steam