Validation of predicted path of thermally deflected ultrasonic waves (phD work on acoustic thermometry in SFR) Nicolas Massacret (PhD Student ) Directors: Joseph Moysan*, Marie-Aude Ploix* CEA tutor: Jean-Philippe Jeannot** * LMA-LCND -FRANCE- (Laboratory of Mechanics and Acoustics - Non Destructive Characterization Laboratory) ** CEA (Atomic Energy Commission) Cadarache 2013/05/22 LE MANS – 13 th NDCM | PAGE 1
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Validation of predicted path of thermally deflected ultrasonic waves
(phD work on acoustic thermometry in SFR)
Nicolas Massacret
(PhD Student )Directors: Joseph Moysan*, Marie-Aude Ploix*
CEA tutor: Jean-Philippe Jeannot**
* LMA-LCND -FRANCE-(Laboratory of Mechanics and Acoustics -
Non Destructive Characterization Laboratory)** CEA (Atomic Energy Commission)
Cadarache -FRANCE-DEN/DTN/STPA/LIET
2013/05/22 LE MANS – 13th NDCM | PAGE 1
Outline
I- Context
II- Ultrasonic measurement advantages and issues
III- Acoustic model and implementation for simulation
IV- Experimental validation
V- Further experimentation
2013/05/22 LE MANS – 13th NDCM | PAGE 2
French option for the 4th generation of nuclear reactor:
SFR project: Sodium-cooled Fast Reactor
In the past: Rapsodie – Phénix – Superphénix (French SFR)
In the future (plan to be built in 2023): ASTRID prototype
Need to develop several innovative and specific instrumentations
based on feedbacks:
For this kind of reactor,
To diversify and enhance current instrumentation,
For the liquid sodium, an opaque fluid banning optical technique.
I- Context
Rapsodie
Phénix
Superphénix
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ASTRID
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METHOD PATENTED IN 1989 BY UKAEA An Ultrasonic Technique for the Remote Measurement of Breeder Subassembly Outlet
Temperature, Instrumentation for the Supervision of Core Cooling in LMFBR's. [Macleod and al. 1989].
THERMOMETRY ISSUES USING THERMOCOUPLE:
(possible influence of neighboring subassemblies, long response time, important volume of instrumentation,…)
Thermometry at the subassemblies outlet:
turbulent area.
I- Context
Context: Thermometry of sodium at the subassemblies outlet :
≈350 thimbles, each one containing
2 thermocouples.
Acoustic instrumentation advantages :
Opacity of sodium is not an issue any more.
It is non-invasive: Acoustic transducer can be away from the measured area.
There is no more thermal inertia of thimble containing thermocouples : so response-time is improved for thermometry.
It is possible to realize a measurement in different areas with only one transducer.
Temperature: Inhomogeneities of sodium temperature
above the core (ΔTmax=50°C)
Speed flow field at the subassemblies outlet: Turbulent flow (Re=60 000),
High speed flow (about. 4 m.s-1) ,Important speed gradient (1.5m.s-1.cm-1).
Deflection and diffusion of ultrasonic waves
However, ultrasonic propagation depends on:
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II- Ultrasonic measurement advantages and issues
Objective : Define an appropriate model for ultrasonic propagation in turbulent fluid, dealing with influence of temperature and flow speed.
Considering the thermo-hydraulics characteristics of the medium (characteristic length of the inhomogeneities, Mach number, …) and thanks to the application of the frozen fluid hypothesis:
Model using the acoustic ray theory and a refractive index based on temperature and flow speed field.
Numerical simulation of transit-time ultrasonic flowmeters: uncertainties due to flow profile and fluid.
[B. Iooss and al. 2000]
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II- Acoustic model and implementation
Numerical Calculation
Acoustic ray equation:
Prediction of ray deflections and delays
Gaussian beam approach
(in development)
Thermo-hydraulics data(from experiment,
simulation, …)
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II- Acoustic model and implementation
Where :r(x,z) is the 2D ray position vector,s is the arc length,t(r) is the unit vector tangent to the ray,(r) is the travel time of the wave on the ray,c(r) is the acoustic celerity,v(r) the fluid velocity vector,S = t/(c+ t.v) is the acoustic slowness vector,= 1-v.S
Principle of the experiment UPSilon (Ultrasonic Path in Silicone oil):
Creation of thermal inhomogeneities in fluid
Propagation of ultrasonic waves across thermal
inhomogeneities
Observation of delays and deflections of ultrasonic waves
Comparison with acoustic ray simulation
Fluid properties : Silicone Oil Very viscous fluid (viscosity : 10 000 cSt) to
avoid convection movement. High dependence of ultrasonic celerity with
the temperature in this medium. As the sodium (and unlike water), this
dependence is linear and the celerity decreases with the temperature.