1. 1 Greg Hallewell / Thermosiphon sonars / ATLAS ID Thermosiphon Workshop, CERN, Oct 20, 2011 Greg Hallewell Centre de Physique des Particules de Marseille Sonar instrumentation for thermosiphons

2. 2 People involved: - Michele Battistin, Stephane Berry, Pierre Bonneau, Gennaro Bozza, Enrico daRiva, Jose Botelho Direito, Didier Lombard, Jan Godlewski team, Lukasz Zwalinski (CERN) - Nicolas Bousson, Greg Hallewell, Michel Mathieu & Sasha Rozanov (CPPM, Marseille) - Richard Bates & Alex Bitadze (Glasgow Univ.) - Kirill Egorov (Indiana Univ.) - Koichi Nagai (Tsukuba Univ.) - Rusty Boyd (Oklahoma State Univ.) - Sergei Katunin (PNPI St. Petersberg) - Martin Doubek, Vic Vacek & Michal Vitek (CTU, Prague) - Steve Mcmahon (RAL/STFC) - Cecilia Rossi (Genova Univ.) Greg Hallewell ATLAS ID Thermosiphon Workshop, CERN, Oct 20, 2011 Sonars for flowmetry and mixture analysis

3. 3  Sonar R&D for C 3 F 8 /C 2 F 6 blend studies Mixture analysis Flowmetry (so far low flows < 30gms -1 ; axial configuration)  Sonar R&D for thermosiphon application Flowmetry (high flows < 1.2kgms -1 ; angled configuration) Mixture analysis (1) for C 3 F 8 /C 2 F 6 if used, using angled configuration (2) for detection of ingressed non-condensible vapour (air, N 2 …) in sub atmospheric pressure surface condenser. Contents Greg Hallewell ATLAS ID Thermosiphon Workshop, CERN, Oct 20, 2011

4. 4 (1) Flowmetry (so far flows < 30gms -1 (blender limit); axial config.) (2) Mixture analysis Sonar R&D for C 3 F 8 /C 2 F 6 blend studies Greg Hallewell ATLAS ID Thermosiphon Workshop, CERN, Oct 20, 2011 Gas analyzer

5. 5 Developed for air at atmospheric pressure, 0-60ºC but used in other gases (hydrocarbon & fluorocarbon-nitrogen mixtures from mid 1980s; Hallewell et al.) & far beyond this temp. & press. range: Open transducer construction: spiral grove lets gas fill and evacuate from both sides of foil allowing high & low pressure operation. The 50kHz ultrasonic transceiver has been around for >25 years!  first developed for Polaroid autofocus cameras (1980’s) now mainly robotics – marketed by Senstech (600 series instrument grade) Greg Hallewell ATLAS ID Thermosiphon Workshop, CERN, Oct 20, 2011

6. Adapted from a slide by Mike Vitek (CTU Prague): presentation at ANIMMA 2011, Ghent 6-9 June 2011 6 Two functions in one instrument 2 capacitative 50kHz ultrasonic transducers 2 PEEK flow deflectors Lateral tubes for calibration gas injection/ pressure sensing 6 NTC temperature sensors Clock Starts Clock Stops Transition time in direction A measured Measuring cycle starts Transition time in direction B measured Greg Hallewell ATLAS ID Thermosiphon Workshop, CERN, Oct 20, 2011

7. 7 Electronics: Main components & functionality V s = (t/0.66m) 50 kHz 40 MHz V s = ((N*25.10 -9 s)/0.66m) Analog Devices ADuC (or Microchip dsPIC33F)  -controller generates 50 kHz ultrasound 'chirps' & synchronously starts 40 MHz transit time clock (later stopped by 1 st over-threshold sound pulse) Then repeats in opposite direction: A  B ; B  A: FIFO generates 20 averages/s of (T A  B, T B  A, Temp, Press) Greg Hallewell ATLAS ID Thermosiphon Workshop, CERN, Oct 20, 2011

8. SCADA Software Ultrasound transducer A generates burst of 50KHz pulses Generated wave captured by the receiving transducer B Transit Time A  B calculated Ultrasound transducer B generates burst of 50KHz pulses Generated wave captured by the receiving transducer A Transit Time B  A calculated Flow rate calculated from (AB-BA) Transit time difference Temperature and pressure in the chamber measured Average sound velocity, c, in the two directions calculated Gas mixture calculated from (c, T, P) look-up table Ultrasonic flowmetry & gas mixture analysis RS232/CAN BUS PVSS-II ANALYSING SOFTWARE V s @ (% blend, P, T) DATABASE MEASURING ELECTRONICS V (T),V (P),V bias, pulses Measuring chain schematics Greg Hallewell ATLAS ID Thermosiphon Workshop, CERN, Oct 20, 2011 A  B A  SONAR TUBE  B

9. 9 Flowmetry: simple axial geometry: entire sound path in gas flow, whole flow constrained to pass through cylinder defined by transducer cross section: Turbulence effects? Flowmetry: simple axial geometry: entire sound path in gas flow, whole flow constrained to pass through cylinder defined by transducer cross section: Turbulence effects? Greg Hallewell ATLAS ID Thermosiphon Workshop, CERN, Oct 20, 2011 Calculation of flow parameters : (Temp., Press. not needed) * Speed of sound: c = L/2 * ((t A + t B )/ t A* t B ) [ms -1 ] * Gas flow velocity: v =L/2 * ((t A – t B )/ t A* t B ) [ms -1 ] * Volume flow: V = v * A [m 3 s -1 ]

10. Calibration against Schlumberger Delta G16 gas meter Greg Hallewell ATLAS ID Thermosiphon Workshop, CERN, Oct 20, 2011

11. Schlumberger  G16 flow (l/min C 3 F 8 ) Ultrasonic FM flow (l/min C 3 F 8 ) Greg Hallewell ATLAS ID Thermosiphon Workshop, CERN, Oct 20, 2011 UFM precision: 2% of full scale flow SD of datapoints w.r.t. fit line Ultrasonic Flowmeter linearity & precision to 230 l.min -1 (30 g.s -1 ) in C 3 F 8, 20°C, 1 bar abs

12. % concentration of gas (A) in gas (B) Sound velocity (ms -1 ) Pre-stored database of sound velocity vs. concentration of gas A in gas B at process P, T; Set up from prior measurements or theory Mixture concentration uncertainty = sound velocity error/local gradient Mixture Analysis Compare sound velocity measured at known temperature, pressure with pre-stored database (determined from measurements in calibbration mixtures or from theoretical prediction Mixture Analysis Compare sound velocity measured at known temperature, pressure with pre-stored database (determined from measurements in calibbration mixtures or from theoretical prediction Greg Hallewell ATLAS ID Thermosiphon Workshop, CERN, Oct 20, 2011

13. Verification measurements Comparison of measured and estimated sound velocities in pure C 3 F 8 and C 2 F 6 refrigerants * Stable temperature C 3 F 8 - temperatures of 19.2-19.4°C C 2 F 6 - temperatures of 19.6-19.7°C * Varying pressure C 3 F 8 – pressures from 0.4 to 2.5bar abs C 2 F 6 – pressures from 1.3 to 2.7bar abs * Estimated values Acquired from the PC-SAFT state equation * Average difference between estimated and measured sound velocity <0.04% (both gases) TempPress ccError MeasuredPredictedAbsRel °Cbar a m.s -1 % 19.40.46116.18116.08 0.10 0.09 19.40.59115.83115.78 0.05 0.04 19.40.99114.86114.84 0.02 0.01 19.41.14114.52114.48 0.04 19.41.51113.59113.58 0.01 19.41.97112.39112.43-0.04-0.03 19.42.41111.29111.30-0.01 TempPress ccError MeasuredPredictedAbsRel °Cbar a m.s -1 % 19.61.31136.72136.73-0.01 19.61.65136.28136.30-0.02-0.01 19.62.03135.79135.81-0.02 19.62.27135.46135.50-0.04-0.03 19.62.39135.26135.34-0.08-0.06 19.62.48135.14135.22-0.08-0.06 19.62.68134.94134.96-0.02 C3F8C3F8 C2F6C2F6 Greg Hallewell ATLAS ID Thermosiphon Workshop, CERN, Oct 20, 2011

14. 14 Comparison of sound velocity measurement & theory predictions: C 2 F 6 /C 3 F 8 : molar concentrations of interest to the ATLAS project Average difference between PC-SAFT (NIST REFPROP extended BWR) predictions & meas. sound velocities < 0.5% (<0.05%) for P < 0.15 MPa & (0 ≤ %C 2 F 6 ≤ 50). Pre-stored database of sound velocity vs. % Conc. of gas A in gas B at process P, T; Set up from prior measurements or theory Mixture concentration uncertainty = sound velocity error/local gradient 0.05% sound vel.  0.3% in mix at 20%C 2

15. Mixture calculating algorithm (2) In mixtures containing non-ideal gases C p /C v variations with P, T (not just with the molar concentrations of the two components) can limit the instrument accuracy. While the perfect sound velocity/concentration database corresponds to the process temperature and pressure, this may not be practical to implement if the process P, T change over a wide range in real time;  Search can be refined by targeting ‘local’ sound velocity/molar concentration curves close to the instantaneous process P,T conditions; ‘zooming’ among set of curves covering the entire expected P,T regime… Zooming software gets the mixture composition corresponding to a minimized 3-norm, n i, in (conc, c, P, T) space, comparing running average process variables in sound vel, temp, Press with %conc curves at nearest P, T Greg Hallewell ATLAS ID Thermosiphon Workshop, CERN, Oct 20, 2011

16. 16 Norm search in local (c vs. %Conc., P, T) space % concentration of gas (A) in gas (B) Sound velocity (ms -1 ) Greg Hallewell ATLAS ID Thermosiphon Workshop, CERN, Oct 20, 2011

17. 3 axial flowmeters/ analyzers built: 2kW TS surface condenser & flow return sonar (with bypass) in point 1 cryo building  Expected flow < 40 gms -1 will give C 3 F 8 /C 2 F 6 analysis capability also, of course 17 Vapour return #3 axial flowmeter/ analyzer sonar with bypass Greg Hallewell ATLAS ID Thermosiphon Workshop, CERN, Oct 20, 2011

18. 18 Vapour return Vapour return Liquid Out Liquid Out Greg Hallewell ATLAS ID Thermosiphon Workshop, CERN, Oct 20, 2011 Vent sonar will be installed above the highest point of condenser

19. 19 Will need to vent any uncondensible gas that ingresses into the (sub-atmospheric pressure) thermosiphon surface condenser Will need to vent any uncondensible gas that ingresses into the (sub-atmospheric pressure) thermosiphon surface condenser Sonar analysis ideal to sample the headspace gas and to trigger vent to vacuum. Greg Hallewell ATLAS ID Thermosiphon Workshop, CERN, Oct 20, 2011

20. 20 From K. Egorov slides: 40 th sonar meeting, September 28, 2011 Greg Hallewell ATLAS ID Thermosiphon Workshop, CERN, Oct 20, 2011

21. 21 Greg Hallewell ATLAS ID Thermosiphon Workshop, CERN, Oct 20, 2011

22. 22 Greg Hallewell ATLAS ID Thermosiphon Workshop, CERN, Oct 20, 2011

23. 23 Temp. (C) Vs (m/s) Superheated vapour V s : of interest, with sonar tube Above condenser temperature (natural warming?) Saturation Temp at 300mbar abs presssure C 3 F 8 with pressure set at 300 mbar abs look at sound velocity vs. temp (crossing from saturated to superheated) NIST Refprop calculations Greg Hallewell ATLAS ID Thermosiphon Workshop, CERN, Oct 20, 2011

24. 24 <10 -4 precision possible at low C 3 F 8 concentrations Greg Hallewell ATLAS ID Thermosiphon Workshop, CERN, Oct 20, 2011

25. 25 For the big thermosiphon, with flow rates around 1.2kg/sec we will need a much bigger flowmeter/ analyzer in the primary fluorocarbon gas circuit For the big thermosiphon, with flow rates around 1.2kg/sec we will need a much bigger flowmeter/ analyzer in the primary fluorocarbon gas circuit Axial and angled geometries are being studied in ~133mm & ~210mm ID tubes using Computational Fluid Dynamics (G. Bozza and E. DaRiva) Greg Hallewell ATLAS ID Thermosiphon Workshop, CERN, Oct 20, 2011

26. 26 EDMS Request to make Computational Fluid Dynamics Studies of Ultrasonic Flowmeter geometries adapted to high flows (1.2 kgs -1 fluorocarbon) in the 60kW thermosiphon installation 60kW thermosiphon installation Greg Hallewell ATLAS ID Thermosiphon Workshop, CERN, Oct 20, 2011 SEE FOLLOWING TALK BY GENNARO BOZZA

27. Results for the Axial Flow Meter with transducers, D=133.7mm, L=20D with the k-ε turbulence model. Greg Hallewell ATLAS ID Thermosiphon Workshop, CERN, Oct 20, 2011 Flow reading deficit due to turbulence behind upstream transducer Flow profile across tube mid way bewteen ultrasonic transducers

28. Results for the Axial Flow Meter with transducers, D=211.6mm, L=5D with the k-ε turbulence model. Greg Hallewell ATLAS ID Thermosiphon Workshop, CERN, Oct 20, 2011 Flow reading defecit due to turbulence behind upstream transducer Flow profile across tube mid way bewteen ultrasonic transducers

29. 29 Large bore axial geometries with fractional cross section sampling have two problems: (1) flow deficit caused by turbulence following upstream transducer (non-linear with increasing flow: calibration would be problematic) (2) transducers do not sample the full with of the flow in the tube  CFD simulations of angled flowmeter geometries Greg Hallewell ATLAS ID Thermosiphon Workshop, CERN, Oct 20, 2011

30. 30 t down = L / (c + v cosΦ), t up = L / (c - v cosΦ); Gas flow velocity v (m/s): v =L/2cosΦ * ((t u – t d )/ t u* t d ) ; Sound velocity c (m/s): c = L/2 * ((t u + t d )/ t u* t d ); Volume flow  m 3 /s  = v * A Greg Hallewell ATLAS ID Thermosiphon Workshop, CERN, Oct 20, 2011 Ball valves allow isolation for transducer removal Sound passes through valve aperture in operation Angled sound path geometries for High flow thermosiphon

31. 31 Greg Hallewell ATLAS ID Thermosiphon Workshop, CERN, Oct 20, 2011 Results look very promising: mechanical prototyping soon

32. 32 (1) Sonar gas analysis has demonstrated high precision for C 2 F 6 /C 3 F 8 & N 2 /fluorocarbon analysis; (2) Pinched axial flowmeter/gas analyzer geometry demonstrated, and OK for the 2kW thermosiphon application (installed in 2kW TS vapour return); (3) Angled ultrasonic flowmeter/gas analyzer geometry best adapted to high flow (60kW) thermosiphon application –  prototyping to start soon; (4) Both geometries can provide a mixture analysis capability if C 2 F 6 /C 3 F 8 blends used with a thermosiphon (5) Headspace analysis necessary for air infiltration into sub-atmospheric surface condenser; test first on 2kW thermosiphon – mechanical design under way Greg Hallewell ATLAS ID Thermosiphon Workshop, CERN, Oct 20, 2011 Conclusions

33. 33 Back-up slides

34. 34 Multipin connector (transducers + temperature sensors) for sonar analyzer/ flowmeter – to be screwed into spoolpieces for 2 * VCR tube extensions (to be designed) CS-MS-A-J-9-BCR-SS Greg Hallewell ATLAS ID Thermosiphon Workshop, CERN, Oct 20, 2011

35. 35

36. 36 44mm transducer attachment & centering via PEEK deflector cone (similar annular area to circular cross section between transducers) ; wire routing toward electrical feed-through, port for evacuation & periodic calibration with reference gas (e.g. Xe) Sonar fluorocarbon analyzer: ATLAS ID Thermosyphon Workshop, CERN, May 28, 2010

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