A Review of a Four-Channel Clamp-On Ultrasonic Flowmeter

Transcription

1 A view of a Four-Channel Clamp-On Ulrasonic Flowmeer Bernhard Funck & Peer Lipro Flexim GmbH, Berlin Page 1 March 2014 Muli-Channel clamp-on ulrasonic measuremen Inroducion Flow profile influences Compensaion wih a muli channel flowmeer CFD-Analysis Laboraory ess Conclusions Page 2 March

2 Non-invasive ulrasonic flow measuremen V!! = A " " vl = A " " a" 2l V! Flow A Cross-secional area l a! Transi ime difference Fluid mechanical calibraion facor Acousic calibraion facor Transi ime in he fluid Page 3 Non-invasive ulrasonic flow measuremen V!! = A " " vl = A " " a" 2l V! Flow A Cross-secional area l a! Transi ime difference Fluid mechanical calibraion facor Acousic calibraion facor Transi ime in he fluid Page 4 2

3 Non-invasive ulrasonic flow measuremen V!! = A " " vl = A " " a" 2l V! Flow A Cross-secional area l a! Transi ime difference Fluid mechanical calibraion facor Acousic calibraion facor Transi ime in he fluid Page 5 Non-invasive ulrasonic flow measuremen V!! = A " " vl = A " " a" 2l V! Flow A Cross-secional area l a! Transi ime difference Fluid mechanical calibraion facor Acousic calibraion facor Transi ime in he fluid Page 6 3

4 Non-invasive ulrasonic flow measuremen V!! = A " " vl = A " " a" 2l V! Flow A Cross-secional area l a! Transi ime difference Fluid mechanical calibraion facor Acousic calibraion facor Transi ime in he fluid Page 7 Influence of flow profiles Compensaion for non fully developed flow profiles Swirl Asymmery Symmeric effecs on flow profiles Field calibraions Correcion facors!" #$%&"'($%)*+,"'()+%-" Page 8 4

5 Influence of flow profiles 2-channel direc mode 2-channel reflec mode 4-channel direc mode 4-channel reflec mode Page 9 Influence of flow profiles Theoreical sudies of profile influences Calibraing fluid mechanical calibraion facors from CFD resuls Mean axial flow velociy on he measuremen pah Mean cross-flow velociy on he measuremen pah 1 va = w( r)! dr D " D 1 vcr = vcr ( r) dr; vcr ( r) = v" sin! + ucos! D # D Measured pah averaging cos! vl _1" Pah = va " vcr sin! Measured pah averaging in reflec mode u x l! Schallpfad v = v l _ flex a Fluid mechanical calibraion facor in reflec mode re _ flex v = v A l _ flex vcr v a v y l " v cr v a w z l Page 10 5

6 Influence of flow profiles Approach o he explanaion of flow profile influences Mechanical fluid calibraion a non-ideal inle condiions: e! z D re = " # re$ + % re0 # Flow profile influences may be adequaely compensaed wih muli-pah arrangemens. re! =Fluid calibraion in ideal condiions; depends on and pipe roughness $ # e! re0 " # z D =Influence of he profile disurbance will depend on he acual characerisics of he disurbance and he pipe roughness I is assumed ha his is independen of where >1E5 Page 11 Influence of flow profiles Theoreical sudy of profile disurbances CFD-Analysis of single and double elbows (ou of plane) Turbulence model: -Omega SST Page 12 6

7 CFD Simulaion Page 13 CFD Simulaion Page 14 7

8 CFD Simulaion Page 15 CFD Simulaion Page 16 8

9 CFD Simulaion Page 17 CFD Simulaion Page 18 9

10 CFD Simulaion Page 19 Laboraory ess Gas calibraion laboraory DNV ema in Groningen, NL Measuremen secion DN100, lengh 5m (50D), carbon seel, Roughness RZ=21µm Configuraion 2 pah (reflec) mode a 90 orienaion Measuremen poins: 5D, 10D, 15D, 30D, 45D Flow velociies: 0.5 o 20m/s (1:40) Naural gas a 20 Bar ynolds numbers: 0.09 o 3.5E6 Page 20 10

11 Laboraory ess Pipe geomeries esed: 1. Ideal inle : Flow sraighener, reducion, 22D sraigh pipe bend flow sraighener, 22D sraigh pipe 90 elbow 2. ducion, flow sraighener, reducion 4. Double bend, flow sraighener, 22D sraigh pipe, double bend Page 21 Laboraory ess Page 22 11

12 Laboraory ess Page 23 Laboraory ess Page 24 12

13 Laboraory ess Page 25 Laboraory ess Page 26 13

14 Laboraory ess Page 27 Laboraory ess Page 28 14

15 Conclusions 1.! The case for increasing he number of measuremen channels is demonsraed 2.! Calibraing for field effecs is simplified 3.! Profile effecs show remarkable similariy (single and double elbows affec measured raes by <1%) 4.! The exponenial based approach is wihin 0.5% of acual measuremen 5.! I is likely ha he disurbance profile is heavily dependen on roughness, a leas downsream Nex: CFD assessmen of pipe roughness effecs Furher ess wih differen (older, rougher) pipes Final 15