Workshop « Towards More Accurate Fixed Points » – St Denis – 23-24 november 2006 1 LNE Center...
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Transcript of Workshop « Towards More Accurate Fixed Points » – St Denis – 23-24 november 2006 1 LNE Center...
Workshop « Towards More Accurate Fixed Points » – St Denis – 23-24 november 20061
LNECenter for Scientific and Industrial
Metrology (CMSI)Thermal & Optical Division29, avenue Roger Hennequin
78197 Trappes, France
Development of a new deviceDevelopment of a new devicefor realizing the indium fixed-pointfor realizing the indium fixed-pointin quasi-adiabatic conditionsin quasi-adiabatic conditions
Development of a new deviceDevelopment of a new devicefor realizing the indium fixed-pointfor realizing the indium fixed-pointin quasi-adiabatic conditionsin quasi-adiabatic conditions
R. Morice ([email protected]),
G. Bonnier, J.C. Barbaras, N. Fleurence, V. Le Sant,G Le Dortz, A Lesauvage, G Failleau, P. Ridoux, J.R. Filtz
Workshop « Towards More Accurate Fixed Points » – St Denis – 23-24 november 20062
Introduction
Euromet 732 project
WP6 Indium fixed point
PTB (WP leader), LNE-CMSI, METAS
LNE-CMSI general objective :
Develop enclosures for realizing ITS-90 fixed
point (t>0.01°C) in quasi-adiabatic conditions
Workshop « Towards More Accurate Fixed Points » – St Denis – 23-24 november 20063
Assess uncertainties due to thermal
parasitic effects in ITS-90 fixed points
Thermal Properties of Materials programme
of LNE-CMSI
TP of pure metals
To facilitate and to improve PRTs calibration ?
65 PRTs / year calibrated or
checked at Ga, In- More simple (limited radiative heat flux …)
- Wide variety of materials available up
to 200 °C
INDIUMFIXEDPOINT
Introduction
Workshop « Towards More Accurate Fixed Points » – St Denis – 23-24 november 20065
Therm om eter
Environm ent
G uard cell
F ixed point ce ll
• Fixed point cell placed in a guard containing a metal of the same nature
• Cell+guard system placed in a thermal enclosure
• Temperature of enclosure adjusted below the melting temperature of the metal
• Fixed point cell melted using heat pulses, in quasi-adiabatic conditions
Principle - new device
• Additional heater to maintain permanently the guard in its phase transition
Heat
Workshop « Towards More Accurate Fixed Points » – St Denis – 23-24 november 20066
The project
to investigate / assess the
previous principle
to understand thermal
aspects of phase transition
(permanent heat flux or heat
pulses)
to optimise the final design
Development of an experimental prototype• construction ( nov 06)• metrological assessment
( march 07)
Development of a thermal model ( end 07)
First step : experimental prototype
Second step : final design ( end 07)
Workshop « Towards More Accurate Fixed Points » – St Denis – 23-24 november 20067
Experimental prototype
Scheme
Constructed for operation with
a well known, « traditional »
indium cell (LNE-INM type)
investigate phase transition
using permanent heat flux
method or calorimetric method
(heat pulse technique)
2 indium guards, 5 guard
heaters, 3 heaters for the indium
cell, 1 TC/heater, 3 heat flux
sensors
Ind ium guardAuxilliaryheaters
Indium cell
Ind ium guard
A irpulsedfurnace
O uter casing
Therm om eter
Workshop « Towards More Accurate Fixed Points » – St Denis – 23-24 november 20068
Preliminary tests - Thermal control of the In guard (1)
Method envisaged : Furnace temperature maintained below melting temperature of indium
Melt initiated in the In guard using heat pulses (heating mode)
Detection of local presence of interface using heat pulses (detection mode)
Ind ium guardAuxilliaryheaters
Indium cell
Ind ium guard
A irpulsedfurnace
O uter casing
Therm om eter
tim e
Tem peraturesensor
Indium(Liquid)
Indium(Solid)
W alls
Workshop « Towards More Accurate Fixed Points » – St Denis – 23-24 november 20069
Preliminary tests - thermal control of the In guard (2)
Temperature of auxilliary heater - « Heating mode »
0
1
2
3
4
0 4 8 12 16
time (min)
in meltend of meltoutside melt
T(t
ime)
- T
(bef
ore
pul
se)
/°C
Workshop « Towards More Accurate Fixed Points » – St Denis – 23-24 november 200610
Temperature of auxilliary heater - « Detection mode »
0
0.5
1
0 100 200 300 400
time (sec)
During phasetransition
Outside phasetransition
ther
mal
pul
se (
norm
alis
ed to
1)
Preliminary tests - thermal control of the In guard (3)
tnorm = (tt-tmin)/(tmax-tmin)
Workshop « Towards More Accurate Fixed Points » – St Denis – 23-24 november 200611
Ind ium guardAuxilliaryheaters
Indium cell
Ind ium guard
A irpulsedfurnace
O uter casing
Therm om eter
Preliminary tests – In lateral guard and In cell (1)
Ind ium cell
Ind ium guard
Therm om eter
H eat fluxsensor
A irpulsedfurnace
Workshop « Towards More Accurate Fixed Points » – St Denis – 23-24 november 200612
155.5
156.0
156.5
157.0
157.5
158.0
158.5
159.0
0 5 10 15 20
time (hours)
tem
pera
ture
(°
C)
Melt of In guard
Melt of In cell
Successive melts of the In guard and In cell usingpermanent heat flux method
Temperature displayed in the thermometer well
Preliminary tests – In lateral guard and In cell (2)
Workshop « Towards More Accurate Fixed Points » – St Denis – 23-24 november 200613
Limited heat flux from auxilliary heaters
Possible detection of local L/S interface along indium cell
Possible detection of non-adiabaticity ( out of heating period) along indium cell
Heat pulses technique :Heat exchange between In guard and In cell when both are melting
= (tg-tc)/Req
Heat pulse 1W / 500 J
Preliminary tests – In lateral guard and In cell (3)
Workshop « Towards More Accurate Fixed Points » – St Denis – 23-24 november 200614
Melt of the indium cell by heat pulses (guard in phase transition)
156
156.2
156.4
156.6
156.8
157
157.2
0 50 100 150 200 250time (min)
tem
pera
ture
(°C
)
Preliminary tests – In lateral guard and In cell (4)
Workshop « Towards More Accurate Fixed Points » – St Denis – 23-24 november 200615
Experimental prototype set up
Cross cut
Details : In lateral guard, In cell, In upper guard
Workshop « Towards More Accurate Fixed Points » – St Denis – 23-24 november 200616
Follow up …
Work currently in progress
• prototype now constructed• assessment : confront methods, numerical model, melt / freeze• uncertainties ?
Next steps
• final design of the setup• aluminium (phD student)