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Transcript of 1 Greg Hallewell / Thermosiphon sonars / ATLAS ID Thermosiphon Workshop, CERN, Oct 20, 2011 Greg...
1Greg 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
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
Sonar R&D for C3F8/C2F6 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 C3F8/C2F6 if used, using angled configuration
(2) for detection of ingressed non-condensible vapour (air, N2…) in sub atmospheric pressure surface condenser.
Contents
Greg Hallewell ATLAS ID Thermosiphon Workshop, CERN, Oct 20, 2011
4
(1) Flowmetry (so far flows < 30gms-1 (blender limit); axial config.)
(2) Mixture analysis
Sonar R&D for C3F8/C2F6 blend studies
Greg Hallewell ATLAS ID Thermosiphon Workshop, CERN, Oct 20, 2011
Gas analyzer
5
Developed for air at atmospheric pressure,Developed for air at atmospheric pressure,0-60ºC but used in other gases 0-60ºC but used in other gases
(hydrocarbon & fluorocarbon-nitrogen (hydrocarbon & fluorocarbon-nitrogen mixtures from mid 1980s; Hallewell et al.) mixtures from mid 1980s; Hallewell et al.)
& far beyond this temp. & press. range:& far beyond this temp. & press. range:Open transducer construction: spiral grove Open transducer construction: spiral grove lets gas fill and evacuate from both sides of lets gas fill and evacuate from both sides of foil allowing high & low pressure operation.foil allowing high & low pressure operation.
The 50kHz ultrasonic transceiver has been around for >25 years!The 50kHz ultrasonic transceiver has been around for >25 years!first developed for Polaroid autofocus cameras (1980’s)first developed for Polaroid autofocus cameras (1980’s)
now mainly robotics – marketed by Senstech (600 series instrument grade)now mainly robotics – marketed by Senstech (600 series instrument grade)
Greg Hallewell ATLAS ID Thermosiphon Workshop, CERN, Oct 20, 2011
Adapted from a slide by Mike Vitek (CTU Prague): presentation at ANIMMA 2011, Ghent 6-9 June 2011
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Two functions in one instrumentTwo 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
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Electronics: Main components & functionalityElectronics: Main components & functionality
Vs = (t/0.66m)
50 kHz
40 MHz
Vs = ((N*25.10-9 s)/0.66m)
Analog Devices ADuC (or Microchip dsPIC33F) Analog Devices ADuC (or Microchip dsPIC33F) -controller -controller generates 50 kHz ultrasound 'chirps' & synchronously generates 50 kHz ultrasound 'chirps' & synchronously
starts 40 MHz transit time clockstarts 40 MHz transit time clock(later stopped by 1(later stopped by 1stst over-threshold sound pulse) over-threshold sound pulse)Then repeats in opposite direction: AThen repeats in opposite direction: ABB; ; BBA:A:
FIFO generates 20 averages/s of (TFIFO generates 20 averages/s of (TAABB, T, TBBAA, Temp, Press), Temp, Press)
Greg Hallewell ATLAS ID Thermosiphon Workshop, CERN, Oct 20, 2011
SCADA Software
Ultrasonic flowmetry & gas mixture analysisUltrasonic flowmetry & gas mixture analysis
RS232/CAN BUS
PVSS-IIANALYSING SOFTWARE
Vs @ (% blend, P, T) DATABASE
MEASURING ELECTRONICS
V(T),V(P),Vbias, pulses
Measuring chain schematics
Greg Hallewell ATLAS ID Thermosiphon Workshop, CERN, Oct 20, 2011
A A SONAR TUBE BB
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Flowmetry: simple axial geometry:Flowmetry: simple axial geometry:
entire sound path in gas flow, whole flow entire sound path in gas flow, whole flow constrained to pass through cylinder defined by transducer cross section: constrained to pass through cylinder defined by transducer cross section:
Turbulence effects?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 * ((tA + tB)/ tA* tB) [ms-1]
*Gas flow velocity: v =L/2 * ((tA – tB)/ tA* tB) [ms-1]
*Volume flow: V = v * A [m3s-1]
Calibration against Schlumberger Delta G16 gas meterCalibration against Schlumberger Delta G16 gas meter
Greg Hallewell ATLAS ID Thermosiphon Workshop, CERN, Oct 20, 2011
Schlumberger G16 flow (l/min C3F8)
Ult
raso
nic
FM
flo
w (
l/min
C3F
8)
Greg Hallewell ATLAS ID Thermosiphon Workshop, CERN, Oct 20, 2011
UFM precision: 2% of full scale flowSD of datapoints w.r.t. fit line
Ultrasonic Flowmeter linearity & precision to Ultrasonic Flowmeter linearity & precision to 230 l.min230 l.min-1 -1 (30 g.s(30 g.s-1-1) in C) in C33FF88, 20°C, 1 bar, 20°C, 1 barabsabs
% concentration of gas (A) in gas (B)
Sou
nd v
eloc
ity (
ms-1
) Mixture concentration uncertainty = sound velocity error/local gradient
Mixture AnalysisMixture Analysis
Compare sound velocity measured at known temperature, pressure with Compare sound velocity measured at known temperature, pressure with pre-stored database (determined from measurements in calibbration pre-stored database (determined from measurements in calibbration
mixtures or from theoretical predictionmixtures or from theoretical prediction
Greg Hallewell ATLAS ID Thermosiphon Workshop, CERN, Oct 20, 2011
Verification measurementsComparison of measured and estimated sound velocities in pure C3F8 and C2F6
refrigerants
*Stable temperature
C3F8 - temperatures of 19.2-19.4°C
C2F6 - temperatures of 19.6-19.7°C
*Varying pressure
C3F8 – pressures from 0.4 to 2.5barabs
C2F6 – pressures from 1.3 to 2.7barabs
*Estimated values
Acquired from the PC-SAFT state equation
*Average difference between estimated and measured sound velocity <0.04%
(both gases)
TempPress
c c ErrorMeasured Predicted Abs Rel
°C bara m.s-1 m.s-1 m.s-1 %
19.4 0.46 116.18 116.08 0.10 0.09
19.4 0.59 115.83 115.78 0.05 0.04
19.4 0.99 114.86 114.84 0.02 0.01
19.4 1.14 114.52 114.48 0.04 0.04
19.4 1.51 113.59 113.58 0.01 0.01
19.4 1.97 112.39 112.43 -0.04 -0.03
19.4 2.41 111.29 111.30 -0.01 -0.01
TempPress
c c ErrorMeasured
Predicted Abs Rel
°C bara m.s-1 m.s-1 m.s-1 %
19.6 1.31 136.72 136.73 -0.01 -0.0119.6 1.65 136.28 136.30 -0.02 -0.01
19.6 2.03 135.79 135.81 -0.02 -0.0219.6 2.27 135.46 135.50 -0.04 -0.03
19.6 2.39 135.26 135.34 -0.08 -0.0619.6 2.48 135.14 135.22 -0.08 -0.0619.6 2.68 134.94 134.96 -0.02 -0.02
C3F8
C2F6
Greg Hallewell ATLAS ID Thermosiphon Workshop, CERN, Oct 20, 2011
14
Comparison of sound velocity measurement & theory predictions: C2F6/C3F8: 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 ≤ %C2F6 ≤ 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 gradient0.05% sound vel. 0.3% in mix at
20%C2
Mixture calculating algorithm (2)In mixtures containing non-ideal gases Cp/Cv 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, ni , in (conc, c, P, T) space, comparing running average process variables in sound vel, temp, Press with %conc curves at nearest P, T
2,3
2,2
2,1 ) - () - () - ( averagerunningtableiaveragerunningtableiaveragerunningtableii cckTTkppkn
Greg Hallewell ATLAS ID Thermosiphon Workshop, CERN, Oct 20, 2011
16
Norm search in local (c Norm search in local (c vs. vs. %Conc., P, T) space%Conc., P, T) space
% concentration of gas (A) in gas (B)
So
un
d v
elo
city
(m
s-1)
Greg Hallewell ATLAS ID Thermosiphon Workshop, CERN, Oct 20, 2011
3 axial flowmeters/3 axial flowmeters/analyzers built:analyzers built:
2kW TS surface condenser 2kW TS surface condenser & flow return sonar (with & flow return sonar (with
bypass) in point 1 cryo buildingbypass) in point 1 cryo building
Expected flowExpected flow< 40 gms< 40 gms-1-1
will give Cwill give C33FF88/C/C22FF66 analysis analysis
capability also, of coursecapability also, of course
17
Vapour return #3 axial flowmeter/ analyzer sonar
with bypass
Greg Hallewell ATLAS ID Thermosiphon Workshop, CERN, Oct 20, 2011
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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 condenserVent sonar will be installed above the highest point of condenser
19
Will need to vent any uncondensible gas that Will need to vent any uncondensible gas that ingresses into the (sub-atmospheric pressure) ingresses into the (sub-atmospheric pressure)
thermosiphon surface condenserthermosiphon 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
20From K. Egorov slides: 40th sonar meeting, September 28, 2011
Greg Hallewell ATLAS ID Thermosiphon Workshop, CERN, Oct 20, 2011
21
Greg Hallewell ATLAS ID Thermosiphon Workshop, CERN, Oct 20, 2011
22Greg Hallewell ATLAS ID Thermosiphon Workshop, CERN, Oct 20, 2011
23Temp. (C)
Vs
(m/s
)
Superheated vapour Vs : of interest, with sonar tubeAbove condenser temperature (natural warming?)
Saturation Temp at 300mbar abs presssure
C3F8 with pressure set at 300 mbarabs 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
<10-4 precision possible at low C3F8 concentrations
Greg Hallewell ATLAS ID Thermosiphon Workshop, CERN, Oct 20, 2011
25
For the big thermosiphon, with flow rates For the big thermosiphon, with flow rates around 1.2kg/sec we will need a much bigger around 1.2kg/sec we will need a much bigger
flowmeter/ analyzer in the primary flowmeter/ analyzer in the primary fluorocarbon gas circuit fluorocarbon gas circuit
Axial and angled geometries are being studiedin ~133mm & ~210mm ID tubes
using Computational Fluid Dynamics(G. Bozza and E. DaRiva)
Greg Hallewell ATLAS ID Thermosiphon Workshop, CERN, Oct 20, 2011
26
EDMS Request to make Computational Fluid Dynamics Studies of Ultrasonic EDMS Request to make Computational Fluid Dynamics Studies of Ultrasonic Flowmeter geometries adapted to high flows (1.2 kgsFlowmeter geometries adapted to high flows (1.2 kgs-1-1 fluorocarbon) in the fluorocarbon) in the 60kW thermosiphon installation 60kW thermosiphon installation
Greg Hallewell ATLAS ID Thermosiphon Workshop, CERN, Oct 20, 2011
SEE FOLLOWINGTALK BY
GENNARO BOZZA
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
transducerFlow profile across tube
mid way bewteen ultrasonictransducers
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
tdown = L / (c + v cosΦ) , tup = L / (c - v cosΦ);
Gas flow velocity v (m/s): v =L/2cosΦ * ((tu – td)/ tu* td) ;
Sound velocity c (m/s): c = L/2 * ((tu + td)/ tu* td);
Volume flow m3/s = v * A
Greg Hallewell ATLAS ID Thermosiphon Workshop, CERN, Oct 20, 2011
Ball valves allow isolation for transducer removalSound passes through valve aperture in operation
Angled sound path geometries for High flow thermosiphon
32
(1) Sonar gas analysis has demonstrated high precision for C2F6/C3F8 & N2/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 C2F6/C3F8 blends used with a thermosiphon
(5) Headspace analysis necessary for air infiltration intosub-atmospheric surface condenser;
test first on 2kW thermosiphon – mechanical design under wayGreg Hallewell ATLAS ID Thermosiphon Workshop, CERN, Oct 20, 2011
ConclusionsConclusions
33
Back-up slides
35
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
37