FEA calculation of pressure distortion coefficients of gas-operated pressure balances – EURAMET project 1039

Sabuga, Wladimir; Priruenrom, Tasanee; Beciet, Gianfranco Molinar Min; Giovinco, Gaspare; Rabault, Thierry; Wongthep, Padipat; Pražák, Dominik

doi:10.1016/j.measurement.2011.10.035

Cited by 11 publications

(9 citation statements)

References 6 publications

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“…The goal of measuring pressures up to 7 MPa with a relative standard uncertainty of order 1 ppm is a challenge because it requires characterisation of pressure balances with unprecedented accuracy and even significant improvement of the national standard of PTB. For absolute pressure measurements in helium up to 7 MPa, a system of special pressure balances, as outlined in [21,22], was designed, constructed and evaluated [2,[23][24][25]; see also the summary in [9]. The system includes two pressure-balance platforms, three pistoncylinder units (PCUs) with effective areas of 20 cm 2 , and three 2 cm 2 PCUs.…”

Section: Pressure Measurementmentioning

confidence: 99%

Final determination of the Boltzmann constant by dielectric-constant gas thermometry

et al. 2017

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Gaiser et al published in 2013 (Metrologia 50 L7-11) a second, improved value of the Boltzmann constant k determined by dielectric-constant gas thermometry at the triple point of water (k = 1.380 6509 × 10 −23 J K −1 , relative standard uncertainty 4.3 parts per million (4.3 ppm)). Subsequently, the uncertainty was able to be reduced to 4.0 ppm by reanalysing the pressure measurement. Since 2013, further progress regarding this primarythermometry method has been achieved in terms of the design and the assembly of the measuring capacitors, the determination of their effective compressibility, the sensitivity of the capacitance bridge, and the scattering and the evaluation of the data. Based on a huge amount of data, two new k values have been obtained by applying two different capacitors. The combination of these two values with the 2013 result, fully taking into account the correlations, has yielded a final result of k = 1.380 6482 × 10 −23 J K −1 with a relative standard uncertainty of 1.9 ppm. This value is about 0.2 ppm smaller than the CODATA 2014 one, which has a relative standard uncertainty of 0.57 ppm.

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Section: Pressure Measurementmentioning

confidence: 99%

Final determination of the Boltzmann constant by dielectric-constant gas thermometry

et al. 2017

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“…For the second goal, it was necessary to characterise pressure balances with an unprecedented quality and even to improve the national standard of PTB significantly. A system of special pressure balances, as outlined in [28,29], was designed, constructed and evaluated [30][31][32][33], see also the summary in [5]. The system includes two pressure-balance platforms, three piston-cylinder units (PCUs) with effective areas of 20 cm 2 and three 2 cm 2 PCUs.…”

Section: Pressure Measurementmentioning

confidence: 99%

Dielectric-constant gas thermometry

2015

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The principles, techniques and results from dielectric-constant gas thermometry (DCGT) are reviewed. Primary DCGT with helium has been used for measuring T-T 90 below the triple point of water (TPW), where T is the thermodynamic temperature and T 90 is the temperature on the international temperature scale of 1990 (ITS-90), and, in an inverse regime with T as input quantity, for determining the Boltzmann constant at the TPW. Furthermore, DCGT allows the determination of several important material properties including the polarizability of neon and argon as well as the virial coefficients of helium, neon, and argon. With interpolating DCGT (IDCGT), the ITS-90 has been approximated in the temperature range from 4 K to 25 K. An overview and uncertainty budget for each of these applications of DCGT is provided, accompanied by corroborating evidence from the literature or, for IDCGT, a CIPM key comparison.

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“…Although the analytical equations for the effective area provided by Dadson et al are unique, see section 2, the methods of measurement of the PCA's geometries and the numerical procedures vary from laboratory to laboratory. These differences were the topic of comparative studies [16][17][18] that confirmed the generally good agreement and highlighted risky points of the primary characterizations of the PCAs. Of course, a value of the PCA effective area obtained from the model of Dadson et al must be further corrected for thermal and pressure induced changes, see e.g.…”

Section: Introductionmentioning

confidence: 72%

“…Of course, a value of the PCA effective area obtained from the model of Dadson et al must be further corrected for thermal and pressure induced changes, see e.g. [18], but these corrections are not within the scope of this paper.…”

Section: Introductionmentioning

confidence: 99%

Analytical solutions of some model cases of piston-cylinder assemblies

Pražák,

Hajduk,

Krajíček

et al. 2021

Meas. Sci. Technol.

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Pressure balances are an important part of the sets of primary pressure standards in many national metrology institutes. The most critical factor determining their accuracy is the effective area of their piston-cylinder assemblies (PCAs). This can be determined (for PCAs with undistorted pressure) by applying a numerical procedure based on a theory by Dadson while knowing a gapprofile (of an axisymmetric PCA approximation). The pressure balances are also a basis for the primary pressure scale of the Czech Metrology Institute. Hence, we wanted to test our programme by computing the effective area from the geometrical data. Therefore, we solved the analytical formulae of Dadson et al (1982) The Pressure Balance—Theory and Practice (London: Her Majesty’s Stationery Office) for several simple geometries with a constant gap width, which are easy to calculate analytically. It is shown that the analytical results always agreed perfectly with the results of our programme. This success confirmed the correctness of our programme. However, it also pointed out a problem of discretization which can be non-negligible, even in the case of relatively simple geometries. We assume that the analytical formulae obtained can be of practical use for any other pressure metrology laboratory requiring an independent way to confirm their own PCA-modelling software.

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FEA calculation of pressure distortion coefficients of gas-operated pressure balances – EURAMET project 1039

Cited by 11 publications

References 6 publications

Final determination of the Boltzmann constant by dielectric-constant gas thermometry

Final determination of the Boltzmann constant by dielectric-constant gas thermometry

Dielectric-constant gas thermometry

Analytical solutions of some model cases of piston-cylinder assemblies

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