Measuring principles Introduction 1

Agenda Measurement 2. Flow technologies 3. Fluid properties

Measurements | flow Certain quantity, which passes section of pipeline or channel in certain time whereby quantity is generic term for mass or volume on gases, volume is depending on pressure and temperature volume on liquids is not depending on pressure because they are not compressible

Flow measurement | orientation Purpose of measurement? Required accuracy, reproducibility? Pipe work lay-out (incl. flow profile, straight in-/outlet length)? Location, surrounding environment? Medium to be measured? Norms, rules, regulations, legislation? Engineering effects (process, pump capacity, personnel, etc.)? Calibration, recalibration? Financial consequences? Cost of ownership?

Agenda 1. Measurement Flow technologies 3. Fluid properties

Technologies | electromagnetic flowmeter Used with electrically conductive fluids Based on Faraday’s law Electrode voltage directly proportional to fluid velocity

Technologies | OPTIFLUX

Technologies | coriolis mass flowmeter Used with fluids and gases Based on Gaspard-Gustave Coriolis Amplitude phase shift is directly proportional with mass flow no flow mass flow

Technologies | OPTIMASS

Technologies | vortex flowmeter Used with fluids and gases Based on Theodore von Karman Frequency of vortices is directly proportional with flow velocity

Technologies | OPTISWIRL

Technologies | ultrasonic flowmeter Doppler used for fluids based on reflection of sound by entrained solids/air frequency shift is proportional with velocity (of entrained solids/air) Transit time used for fluids and gases based on ultrasonic signal travelling diagonally back and forth time difference is proportional with velocity

Technologies | ultrasonic flowmeter Inline single beam dual beam triple beam multi-beam Clamp-on stationary portable

Technologies | OPTISONIC

Technologies | variable are flowmeter Used for fluids and gases Variable area have conical section where float is working Three forces are acting on float: gravity force and weight from top, volumetric flow from bottom Float is pushed up from flow and resides at point where differential pressure below upper and lower surface balances weight of float Movement from float is transported to local display

Technologies | OPTIFLOAT

Technologies | flow switches Flow / no flow detection Fluid / gas detection Examples (flow / no flow) Examples (fluid / gas) mechanical, target or flap switch thermal level and flow switch thermal flow switch vibration fork variable area with contact capacitive sensor dP electromagnetic insertion

Technologies | DW(M)

Technologies | overview

Agenda 1. Measurement 2. Flow technologies Fluid properties

Flow measurement | fluid types

Fluid Properties Density (r) Viscosity (n or h) Reynolds Number (Re) 22

Fluid Properties - Density Liquids: Density changes much less with Temperature and Pressure (effect nearly zero) Gases: Ideal gas law: r = p x M Z x R x T Where: P=pressure [N/m2] R=Universal gas constant 8.31434 103 [J /kmol K] Z= compressibility factor (about 1) r= Density [kg/m3] T= Temperature [K] ( K = degC + 273.15) M= mole mass of fluid [kg/kmol]

Fluid Properties - Viscosity Viscosity: the resistance to flow Dynamic viscosity h [N.s/m2, Pa.s, cP] Kinematic viscosity n [m2/s, cSt]) The relation between kinematic – and dynamic viscosity: n = h / r

Fluid Properties - Viscosity Different viscosity behaviour Dynamic viscosity Newtonian t=h.dv/dy Non-Newtonian Time independent Time dependent

Fluid Properties - Viscosity Newtonian: Ratio Shear stress with shear rate is constant Viscosity changes only with respect to temperature Examples: water, oil, gases Shear rate, dv/dy [s-1] Shear stress [N/m2] Newtonian

Fluid Properties - Viscosity Non-Newtonian & time independant viscosity varies with given temperature and (flow) velocity Dilatant : e.g. starch suspension Structurviscos : e. g. yoghurt, dressing, ketchup Plastic : e.g. tooth paste, hand cream

Fluid Properties - Viscosity Non-Newtonian & time dependant viscosity varies with …. Visco-elastic : e.g. polymer solutions, plastics, flour dough Thixotropic : e.g. pseudo plastic emulsions of soaps Rheopectic : e.g. printer ink

Fluid Properties - Viscosity Shear rate, dv/dy [s-1] Shear stress [N/m2] Newtonian Bingham fluid Dilatant/ Thixotrop Pseudo plastic

Fluid Properties – Effect of viscosity and flow Shape of flow profile is affected This may result in flow measurement errors (especially if you measure in one section Bingham Pseudoplastic Newtonian Dilatant

Fluid Properties - Reynolds Number Reynolds number describes the relation between - flow velocity (v) - diameter (D) - dynamic viscosity () and density (r) Re = v x D x r  The Reynolds number is the only parameter that describes the flow Consequently the flow profile is described by the Reynolds number

Re Reynolds number T R A N S I E Re < 2300 Laminar flow profile Turbulent flow profile T R A N S I E

Flow profile Reynolds Number: Turbulent flow Laminar flow Turbulent flow - Flattened shape - Re >  4.000 Laminar flow - Parabolic shape - Re <  2.300 Transition region - in unfavourable process conditions e.g. high viscosities, low flow rates - 2300 < Re < 4000 - Unpredictable measurement uncertainty Reynolds Number:

Reynolds Number Water Always turbulent Re >  2.300

Reynolds Number Oil Viscosity: 50 cSt Can have both Turbulent & Laminar flow profiles Viscosity ↑ Re ↓ Meter size ↑ Re ↑ Flow rate ↑ Re ↑

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