Advancement of the sonar fluorocarbon mixture analyzer for C2F6/C3F8 evaporative cooling development
Greg Hallewell
Centre de Physique des Particules de Marseille
Sonar fluorocarbon analyzer: ATLAS ID Thermosyphon Workshop, CERN, May 28, 2010 1 Development of sonar fluorocarbon mixture analyzer for C2F6/C3F8 evaporative cooling development
People involved:
Michele Battistin, Jan Godlewski, Elena Perez Rodriguez (CERN) Greg Hallewell, Dirk Hoffmann, Michel Mathieu & Sasha Rozanov (CPPM) Jose Botelho Direito (Univ. Coimbra/CERN) Lukasz Zwalinski (Crackow Institute of Technology/CERN) Richard Bates & Alex Bitadze (Glasgow) Kirill Egorov (Indiana) Danilo Giugni (Milano) Keita Hanawa & Koichi Nagai (Nagoya Univ.) Rusty Boyd (Oklahoma State) Sergei Katunin (St Petersberg) Martin Doubek, Vic Vacek & Michal Vitek (CTU, Prague) Steve Mcmahon (RAL/STFC)
2 Sonar fluorocarbon analyzer: ATLAS ID Thermosyphon Workshop, CERN, May 28, 2010 But why does ATLAS silicon need
C2F6/C3F8 evaporative cooling?
Sonar fluorocarbon analyzer: ATLAS ID Thermosyphon Workshop, CERN, May 28, 2010 3 Current as-built ATLAS tracker C3F8 evaporative cooling system
Condensation @ ~50 C Hot water H.Ex.
17.0 10.0 ) Liquid
abs Mixed Phase Zone Zone Evaporation @ ~-25 C 1.07
Pressure (bar Pressure 0.90 Pressure drop(mainly capillary) Cooling capacity followed by J.T. expansion ~75 J/g Vapour Zone
175 200 225 250 275 300 Enthalpy (kJ/kg)
SameLooking principle at blending as A/C, C2 F(but6 with 324 C parallel3F8 to raise channels: evaporation 60kW): pressure (7) piston and compressorat exploiting reliability 92m poorATLAS & d pitP in depth compressor to eliminate aspiration compressors lines too high
Sonar fluorocarbon analyzer: ATLAS ID Thermosyphon Workshop, CERN, May 28, 2010 4 Advantages of a modest C2F6 admixture (1)
Full thermodynamic cycle simulation C3F8/C2F6 PC-SAFT equation of state molecular simulations
At -25ºC in 10%C2F6/90%C3F8 median evaporation pressure is around 2barabs Pressure drop problem in exhaust tubing mitigated
Sonar fluorocarbon analyzer: ATLAS ID Thermosyphon Workshop, CERN, May 28, 2010 5 Advantages of a modest C2F6 admixture (2)
Full thermodynamic cycle simulation C3F8/C2F6 PC-SAFT equation of state molecular simulations
At -25ºC in 20%C2F6/80%C3F8 median evaporation pressure
is around 3barabs Pressure drop problem in exhaust tubing mitigated
Sonar fluorocarbon analyzer: ATLAS ID Thermosyphon Workshop, CERN, May 28, 2010 6 Why sonar analysis of gas mixtures?
- Velocity of sound in a binary gas mixture at known temperature & pressure is a unique function of their relative molar concentrations;
- Sonar gas analyzer is an in-line/on-line instrument in the gas delivery circuit,
instantaneous response well adapted to updating cursor display
without the delay inherent in (e.g.) gas extraction to a gas chromatograph; - Depending on the difference in molecular weight of the components, mixture measurement precision to 10-5 is possible - Already considerable experience & success with the technique for Cherenkov radiator refractivity monitoring (SLDDELPHI COMPASS LHCb etc.) However it is a binary device; for mixing multiple gases an additional cell is needed after each stage of mixing (eg. 2 cells for Anesthesia trimix…) 7 Sonar fluorocarbon analyzer: ATLAS ID Thermosyphon Workshop, CERN, May 28, 2010 First sonar binary gas analysis use for C5F12/N2 radiator refractivity analysis: SLAC-SLD CRID (1988) Later adopted in DELPHI, COMPASS, LHCb…
Vs T
P
Sonar fluorocarbon analyzer: ATLAS ID Thermosyphon Workshop, CERN, May 28, 2010 8 SLAC SLD Barrel CRID Radiator Vessel
Still using these transducers in the present project
One of 12 45 kHz Polaroid ultrasonic transducers (Ø= 44mm): 6 pairs at three different heights, North and South of central -80KV drift tube cathode/potential degrader
9 SLD CRID C5F12/N2 (short: DH ~ 1.5m) thermosyphon recirculator
(A) C5F12 Condenser (cooled with GN2)
(B) C5F12 storage tank and N2 separator
LN2 conditioner (Chills GN2 in counterflow with LN2 DH from liquid argon calorimeter source)
(C) C5F12 Evaporator
Sonar fluorocarbon analyzer: ATLAS ID Thermosyphon Workshop, CERN, May 28, 201010 Sonar in the SLD CRID C5F12/N2 (short: DH ~ 1.5m) thermosyphon recirculator
A Low temperature N2 gas-induced condensation of C5F12/N2 radiator gas followed by electric re-evaporation B (1-1.5m below condenser liq. level)
Cold N2 gas (‘conditioned’ by D counterflow with boil-off LN2 from liquid argon calorimeter) C
Sonar analyses C5F12/N2 after N2 admixture and before entry into Cherenkov radiator vessel
Sonar fluorocarbon analyzer: ATLAS ID Thermosyphon Workshop, CERN, May 28, 201011 Also SLD CRID combined sonar mixture analyzer/flowmeter: sends sound alternately in both (u,d) directions for flow measurement…
L ~ 50 cm
Flange Ø ~ 10cm
Sonar fluorocarbon analyzer: ATLAS ID Thermosyphon Workshop, CERN, May 28, 201012 Principle of combined ultrasonic flowmeter/ gas analyzer
Flowmetry: measure d(transit time) up(down) stream in fluid flow: Most general case, sound injected angle at j to the fluid flow
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 n (m3/s) : n = v * A
Note: knowledge of gas temperature not necessary
Analysis: use average d(transit time) up(down) and abs temp and use some theory: NEED TEMPERATURE
Tempting but only really valid for ideal gases (monatomics, He, Ne, Ar, Kr, Xe) Sometimes OK for N2, O2… 13 Sonar fluorocarbon analyzer: ATLAS ID Thermosyphon Workshop, CERN, May 28, 2010 Sonar fluorocarbon analyzer: ATLAS ID Thermosyphon Workshop, CERN, May 28, 201014 Sonar flowmeter/analyzer mechanical structure
The following slides adapted from presentation & images created by Jose Botelho Direito (EN/CV/DC), who has designed the mechanical structure for the sonar gas mixture analyzer
The first sonar flowmeter/analyzers foreseen for installation in the USA15 thermosyphon and in a new mixed fluid circulation system at SR1, which will allow cooling studies using C3F8/C2F6 mixtures
Sonar fluorocarbon analyzer: ATLAS ID Thermosyphon Workshop, CERN, May 28, 201015 Sonar installations foreseen in thermosyphon surface plant (return to condenser and degassing tank)
16 Sonar fluorocarbon analyzer: ATLAS ID Thermosyphon Workshop, CERN, May 28, 2010 Detailed Overview (without Flanges)
Sonar Flow meter/ Analyzer 10 Overview
9
8
5 6 4 (1) Tube DN40 (2) Reduction DN65 to DN40 3 (3) Sensor (4) Spider (sensor holder) 2 (5) PEEK Cone (6) Tube extension DN65 with 2 welded metric 10/8mm and 6/4mm tubes (7) Schrader valve (8) VCR Male Nut SS-8-VCR-4 7 (9) VCR glands 6LV-8-VCR-3-10MTB7 1 (10) VCR Female Nut SS-8-VCR-1 29/04/2010 Sonar Flowmeter/Analyser 18 Sonar fluorocarbon analyzer: ATLAS ID Thermosyphon Workshop, CERN, May 28, 2010 General Drawing (No External Pipe Flanges)
29/04/2010 Sonar Flowmeter/Analyser 19 19 Sonar fluorocarbon analyzer: ATLAS ID Thermosyphon Workshop, CERN, May 28, 2010 Sonar analyzer to be built using components (including flares, CF UHV 152/100 Flanges etc.) readily available in CERN stores
29/04/2010 Sonar Flowmeter/Analyser 20 20 Sonar fluorocarbon analyzer: ATLAS ID Thermosyphon Workshop, CERN, May 28, 2010 General Drawing
29/04/2010 Sonar Flowmeter/Analyser
Sonar fluorocarbon analyzer: ATLAS ID Thermosyphon Workshop, CERN, May 28, 2010 21 21 Detailed Overview (showing flanges) Design follows 40/60 max. service/ test specification for all thermosyphon components
2 3 4.a
1 4. 6 b 7
5
(1) Reduction DN65 to DN50 (Connection to plant) (2) Bolts DIN EN 24014 M8x55 (3) Washers ISO 7089 M8 (4) (4.a & 4.b) CF UHV Rotatable Flange CERN SCEM Code 18.60.18.365.2 (5) Tube DN65 (6) CF UHV Flange CERN SCEM Code 18.60.18.015.1 (7) Nuts DIN EN 24032 M8 29/04/2010 Sonar Flowmeter/Analyser 22 22 Sonar fluorocarbon analyzer: ATLAS ID Thermosyphon Workshop, CERN, May 28, 2010 Overview CF UHV Flanges 152/100
Total weight = 12.2 kg
29/04/2010 Sonar Flowmeter/Analyser
23 Sonar fluorocarbon analyzer: ATLAS ID Thermosyphon Workshop, CERN, May 28, 201023 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)
24 Sonar fluorocarbon analyzer: ATLAS ID Thermosyphon Workshop, CERN, May 28, 2010 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
25 Sonar fluorocarbon analyzer: ATLAS ID Thermosyphon Workshop, CERN, May 28, 2010 Sonar analyzer/flowmeter; new electronics development
Sonar fluorocarbon analyzer: ATLAS ID Thermosyphon Workshop, CERN, May 28, 201026 Basic ultrasonics functionality (one of two directions shown)
50 KHz sound clock, 40 MHz transit clock Also analog inputs: - Temperature sensors; -Pressure sensor And analog outputs: -4-20mA DAC drive signal to PLC controlling C2F6 mass flow controller for on-line correction of C2F6 /C3F8 mix ratio Digital communication: - via RS232 to PVSS GUI – CAN in production version 27 Sonar fluorocarbon analyzer: ATLAS ID Thermosyphon Workshop, CERN, May 28, 2010 Sensitive to first sound peak and successive zero crossings 50 kHz , 5 pulses, Air , length: ~ 557 mm: repeatability ~ 50ns in ~ 1.6ms @ fixed T, P
28 Sonar fluorocarbon analyzer: ATLAS ID Thermosyphon Workshop, CERN, May 28, 2010 Sonar test stand in SR1 – May 2010 : 56 cm tube
29 Sonar fluorocarbon analyzer: ATLAS ID Thermosyphon Workshop, CERN, May 28, 2010 Sound Velocity/ concentration look up tables
A sonar analyzer compares measured sound velocity at known T&P for comparison with a stored look-up table fit to (Vs vs % concentration A in B) at known T&P. This look up table can be established theoretically using an equation of state, mixing rules and thermodynamic data for fluorocarbons or else from measurements with calibration mixtures as was necessary at SLD in the 1980s Calibration equation can be shifted from the calibration temperature to the sonar tube temperature using √(T1abs/T2abs), providing this is not so far as to substantially affect (Cp/Cv) in the components. In practice, sound velocity has been used as a test of thermodynamic predictions of evolving equations of state…
30 Sonar fluorocarbon analyzer: ATLAS ID Thermosyphon Workshop, CERN, May 28, 2010 Theoretical underpinning (some thermodynamics)
Speed of sound is a valuable prediction of thermodynamic equations of state, together with pressure-enthalpy phase diagrams etc.
Sonar fluorocarbon analyzer: ATLAS ID Thermosyphon Workshop, CERN, May 28, 201031 For most gases, and certainly mixtures, we need more realistic equations of state than the ‘Ideal Gas’ E.O.S. Simplest ‘realistic’ is the Van der Waals EOS:
Other ‘Empirical’ EOS, e.g. Benedict-Webb-Rubin use ‘reduced parameters’ to calculate compressibility (Z=PV/T) etc. and can be combined with ‘mixing rules’.
Problem: hard to find VDW coefficients for fluorocarbons in 1980s- we approximated using those of hydrocarbons of similar n-structures…
Also hard to find coefficients for FCs in 1980s
Sonar fluorocarbon analyzer: ATLAS ID Thermosyphon Workshop, CERN, May 28, 201032 Speed of sound is a valuable tool in EOS verification: EOS have developed significantly since 1990s: new thermodynamic parameters have been extensively added to NIST databases for
saturated fluorocarbons: R218 (C3F8), R116 (C2F6) or R610 (C4F10) (Vaclav Vacek et al Czech Technical University, Prague for ATLAS collaboration) most recently the new PC-SAFT EOS (“Perturbed Chain Statistical Associating Fluid Theory”)
PC-SAFT equation of state adopts a hard-sphere chain fluid as a reference fluid. The EOS, contains a reference hard-chain EOS and a perturbation contribution.
Z=Pv/(RT) is the compressibility factor, See back-up slides for more details P is the pressure, v is the molar volume, on the perturbation theory, R denotes the gas constant, if interested T is the absolute temperature, A is the Helmholtz free energy, N is the total number of molecules, k is the Boltzmann constant, and superscripts hc, and pert denote the hard-sphere
chain reference equation of state, and the perturbation contribution, respectively Sonar fluorocarbon analyzer: ATLAS ID Thermosyphon Workshop, CERN, May 28, 201033 Verification of the PC SAFT EOS for C3F8, C4F10 and C3F8/C4F10 mixtures
C3F8/C4F10 C F Vs C3F8 Vs 4 10 Vs T T T P P P
Sonar fluorocarbon analyzer: ATLAS ID Thermosyphon Workshop, CERN, May 28, 201034 PC-SAFT Speed of sound in C3F8/C2F6 @ 1 bara& 25 ºC
- Timing shift of 5.5*10-6s.%-1 - 50ns edge detection precision seen with ~40MHz transit clock system - Better precision expected with full zero-crossing algorithm
Slope ~ 0.16ms-1/%
Plan to compare with calibration mixtures made at Marseille June 2010
Sonar fluorocarbon analyzer: ATLAS ID Thermosyphon Workshop, CERN, May 28, 201035 CPPM C2F6/C3F8 mixing station feeding 56cm sonar tube
Sonar fluorocarbon analyzer: ATLAS ID Thermosyphon Workshop, CERN, May 28, 201036 A sonar for measuring possible C3F8 contamination in pixel N2 environmental gas is already operational in ATLAS…
Sonar fluorocarbon analyzer: ATLAS ID Thermosyphon Workshop, CERN, May 28, 201037 USA15 sonar rack for pixel environmental gas monitoring (Copy of CPPM rack: uses SLAC sonar driver & amp/disc, with E-LMB & NIM electronics, PVSS-II graphical user interface)
Sonar fluorocarbon analyzer: ATLAS ID Thermosyphon Workshop, CERN, May 28, 201038 On USA15 SCT1 Pix nose A Pix nose C USA 15 ID wall 2357961 2357991 Y61?-04-X1 Pix SCT2 ID EPA ID EPC Gas Stream Y59-04-X1 Y62-04-X1 2357921 2358011 Sampling Layout
Rack Pix SCT « CO2 » Y59-24-A2
Calib gas in (usually Xenon)
To Ecotek LD (P. Bonneau) or GC (S. Konavalov) Tube P (-1+1 barg)
Sonar tube Twin oil To air ventilation bubbler system
Membrane pump 39 To GC (S. Konavalov) CPPM+ USA15 sonar transit clock panel in PVSS-II user interface
Average counts in pure N2 5405.5: -1 Vs = 350.55 ms Air
Pure N2
Average Temp (4PT100s+ 5NTCs): 19.49°C Crude use of ideal gas eq. of state with g=1.404:
Vs =√(1.404*8.314*(273.15+19.49)/0.028) 349.29 ms-1
Sonar fluorocarbon analyzer: ATLAS ID Thermosyphon Workshop, CERN, May 28, 201040 CPPM+ USA15 sonar transit clock panel in PVSS-II user interface
Average counts in Air: 5541.4: -1 Vs = 341.94 ms Air
Pure N2
Average Temp (4PT100s+ 5NTCs): 19.49°C Crude use of ideal gas eq. of state with g=1.400:
Vs =√(1.40*8.314*(273.15+19.49)/0.028959) 342.96 ms-1 We see sensitivity to changes in composition
equal to a single unit of molecular weight… 41 Sonar fluorocarbon analyzer: ATLAS ID Thermosyphon Workshop, CERN, May 28, 2010 CPPM+ USA15 sonar transit clock panel in PVSS-II user interface
Average counts 16397.6: -1 Vs = 115.5 ms Average Temp (4PT100s+ 5NTCs): 19.25°C PC-SAFT prediction at this temperature and pressure 115.0 ms-1
42 Sonar fluorocarbon analyzer: ATLAS ID Thermosyphon Workshop, CERN, May 28, 2010 Sonar tube temperature panel in PVSS-II user interface
Sonar fluorocarbon analyzer: ATLAS ID Thermosyphon Workshop, CERN, May 28, 201043 PC-SAFT Speed of sound data in C3F8/N2 at 1 bara, 25ºC
Need to compare with measurements in CPPM /USA15 sonar tube – June 2010
Sonar fluorocarbon analyzer: ATLAS ID Thermosyphon Workshop, CERN, May 28, 201044 Conclusions Sonar binary gas analysis is a proven, sensitive and reliable technique used in high energy physics over more than 20 years; The technique has been applied to other gas mixing applications: hydrocarbons, vapours for MOCVD semiconductor fabrication and has been tested with anesthesia gas mixtures; A sonar, based on a SLAC/CPPM/CTU Prague development, is continuously operating (since 3 months) in USA15 to examine pixel environmental gas for possible C3F8 contamination;
In C2F6 / C3F8 mixtures (DMW= 50 units) in the 1-20% range 50ns resolution electronics should provide <<10-3 scale mixture sensitivity. Functioning of the sonar, monitoring and control of C2F6 / C3F8 mixtures will be studied as part of the C2F6 / C3F8 cooling study program being defined for SR1 in the latter half of 2010. Integration into the ATLAS pit thermosyphon demonstrator is planned for refrigerant mixture studies in a 70+ metre thermosyphon.
Sonar fluorocarbon analyzer: ATLAS ID Thermosyphon Workshop, CERN, May 28, 201045 Back up slides
Sonar fluorocarbon analyzer: ATLAS ID Thermosyphon Workshop, CERN, May 28, 201046 Details Polaroid 600 series instrument grade and commercial grade ultrasonic transducers
Sonar fluorocarbon analyzer: ATLAS ID Thermosyphon Workshop, CERN, May 28, 201047 Sonar fluorocarbon analyzer: ATLAS ID Thermosyphon Workshop, CERN, May 28, 201048 Spider
49 29/04/2010Sonar fluorocarbon analyzer: ATLASSonar ID Flowmeter/Analyser Thermosyphon Workshop, CERN, May 28, 2010 Tube DN65 (Spider Holder)
50 29/04/2010Sonar fluorocarbon analyzer: ATLASSonar ID Flowmeter/Analyser Thermosyphon Workshop, CERN, May 28, 2010 PEEK Cone
51 29/04/2010Sonar fluorocarbon analyzer: ATLASSonar ID Flowmeter/Analyser Thermosyphon Workshop, CERN, May 28, 2010 Sonar fluorocarbon analyzer: ATLAS ID Thermosyphon Workshop, CERN, May 28, 201052 What do you need for the effective use of the PC SAFT equation? The hard-chain contribution Based on Wertheim‟s thermodynamic perturbation theory of first order Chapman et al. developed an equation of state, which for hard-sphere chains comprising m segments is given by
(1)
(2)
(3)
where xi is the mole fraction of chains of component i, mi is the number of segments in a chain of hs component i, r is the total number density of molecules, gii is the radial pair distribution function for segments of component i in the hard sphere system, and superscript 'hs' indicates quantities of the hard-sphere system. Expressions of Boublik and Mansoori et al. are used for mixtures of the hard- sphere reference system in Eq. (1) and (2), given by
where m = {0,1,2,3}
with di being a temperature dependent segment diameter of component i , according to 53 53 “SONAR Workshop for ATLAS ID cooling consolidation, 22.04.2010 at CERN V. Vacek, CTU Prague What do you need for the effective use of the PC SAFT equation?
The perturbation contribution
The second-order perturbation theory of Barker and Henderson was extended to chain molecules. The perturbation contribution is the sum of the first and second order term, according to
Van der Waals one fluid mixing rules are usually adopted to extend the perturbation terms to mixtures.
Conventional combining rules are employed to determine the parameters between a pair of unlike segments
Where the compressibility factor is given by
with
Where the packing fraction h is defined by 54 54 “SONAR Workshop for ATLAS ID cooling consolidation, 22.04.2010 at CERN V. Vacek, CTU Prague Complete set of parameters of gases and saturated fluorocarbons for the PC-SAFT EOS
“Our” mixtures are investigated in PC-SAFT using the conventional Berthelot-Lorentz combining rules. The parameters between the pair segments are given as follows
where kij is the unknown binary interaction parameter that is to be defined on the basis of the available experimental data or at the first approach it can be set as the “zero”
55 55 “SONAR Workshop for ATLAS ID cooling consolidation, 22.04.2010 at CERN V. Vacek, CTU Prague Working with mixtures and PC-SAFT EOS General rules remains – some notes: The main difference lies in the fact that for instance the binary mixture has two degrees of freedom; this means that, e.g., at a fixed temperature, the mixture state must be defined by two other quantities, i.e. by the total pressure and by the composition. The partial vapor pressures of the ideal solution of two liquids are related to the composition of the liquid
mixture xi in terms of Raoult‟s law: The mixture composition can be defined e.g. by the overall mole fraction z of component B, From Dalton‟s law p = pA+pB B defined as Combining Raoult and Dalton‟s laws:
The amount of the liquid phase (L) and the vapor phase (V) can be determined from the compositions of
phases xA and yA by the so called „lever rule‟
The phase equilibrium of the two-component mixture is usually interpreted by temperature–composition pressure–composition or diagrams
56 56 “SONAR Workshop for ATLAS ID cooling consolidation, 22.04.2010 at CERN V. Vacek, CTU Prague SLAC Sonar Driver Circuit (ECL input, 200-360V typ.bias)
Driver output : 50 kHz BIAS = 20V
0V
Comparator output TTL signal 0V – no signal 5V – pluse 0V
Sonar fluorocarbon analyzer: ATLAS ID Thermosyphon Workshop, CERN, May 28, 201057 SLAC Sonar Amp/Disc Circuit (ECL output, 80-360V bias)
Amplifier Comparator
Discriminator output
noise
Driver (ECL input)
58 Sonar fluorocarbon analyzer: ATLAS ID Thermosyphon Workshop, CERN, May 28, 2010 ELM & NIM
Sonar fluorocarbon analyzer: ATLAS ID Thermosyphon Workshop, CERN, May 28, 201059 60 Sonar fluorocarbon analyzer: ATLAS ID Thermosyphon Workshop, CERN, May 28, 2010