Progress in development of controlled-clearance pressure balance in NMIJ

Kajikawa, Hiroaki; Ide, Kazunori; Kobata, Tokihiko

doi:10.1088/1742-6596/215/1/012174

Cited by 3 publications

(4 citation statements)

References 3 publications

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“…For p m above 900 MPa, d j − p j is almost a flat line. Non-constant d j is also found by other researchers [13,17,21,36]. d j for the stall jacket pressure is determined by extrapolating d j − p j curve to p j z .…”

Section: Resultssupporting

confidence: 55%

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Characteristic analysis of a controlled-clearance piston-cylinder assembly up to 1500 MPa using a finite element method

Liu,

Wang,

Zhang

et al. 2023

Metrologia

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We utilized numerical methods to analyze the characteristics of the piston-cylinder assembly of a controlled-clearance piston gauge. The piston gauge was able to measure liquid pressure from 100 MPa to 1500 MPa with relative expanded uncertainty of 0.02 % (k = 3). We established a finite element model to solve the stress and strain of the structural problem. The effective areas were calculated based on Dadson’s formula using the converged solutions of the clearance and the pressure distribution within the distorted piston-cylinder engagement gap that were iteratively determined by the finite element model and a fluid mechanics model with pressure-dependent fluid’s properties. Results were compared to the effective areas calculated by the modified Heydemann-Welch model based on experimental data, and the relative differences were less than 0.02%. We found sharp declines of the clearance and pressure distribution near the exit of the piston-cylinder engagement gap, which may lead to wearing during long-time operation at high pressures. Numerical results indicated non-linear relationship between jacket pressure and the cubic root of piston fall speed, which was traditionally considered as linear. The stall jacket pressure obtained by cubic (instead of linear) fitting extrapolation was found more close to the ones determined directly by the finite element model. Numerical results also found non-linear relationships among jacket pressure, measuring pressure, jacket pressure distortion coefficient.

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Section: Resultssupporting

confidence: 55%

“…The corresponding elastic distortion coefficient λ is then determined by equation ( 16) with A 0 defined in equation (17). Results for p m = 100 MPa ∼ 1500 MPa at operational piston fall speed v p = 0.2 mm min −1 and 0.1 mm min −1 are shown in figure 13, as well as λ obtained by the modified H-W model based on experiment data.…”

Section: Resultsmentioning

confidence: 99%

Characteristic analysis of a controlled-clearance piston-cylinder assembly up to 1500 MPa using a finite element method

Liu,

Wang,

Zhang

et al. 2023

Metrologia

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“…While the pressure more than 50 MPa, the main uncertainty contribution of the pressure measurement becomes to . Therefore, the controlled-clearance piston gauge (CCPG) is widely used as the primary standard in many NMIs [1,2,3] for high pressure scale in order to realize and optimize the uncertainty estimation of  The pressure laboratory of National Institute of Metrology (Thailand), NIMT started to establish the gas primary pressure standards from 1.5 to 350 kPa since 2012 by using the dimensional properties to determine A0 [4]. Then the pressure standard obtained from the dimensional measurement were initially used to determine the effective area at zero pressure (A0) up to pressure 500 MPa by using the crossfloating method.…”

Section: Introductionmentioning

confidence: 99%

ESTABLISHMENT OF THAILAND PRESSURE STANDARD FROM 1.5 kPa TO 500 Mpa

Wongthep¹,

Sainoo²

2023

Proceedings of the 6th IMEKO TC16 Conference on Pressure and Vacuum Measurement

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This paper describes the method used to characterize the zero-pressure effective area (A0) and pressure distortion coefficient () of 200MPa-CCPG oil piston-cylinder unit (PCU) in order to realize the national pressure scale from 1.5 kPa to 500 MPa. The A0 was determined by cross-floating method from a set of primary gas pressure standard, while the H-W method was used for calculating . A set of three oil PCUs was maintained as a primary pressure standard and used for scaling up and down pressure to determine  for the other PCUs. The relative standard uncertainty of 200MPa-CCPG pressure standard is 3.010 -5 .

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“…At pressures up to 500 MPa, d is determined by a comparative method using another pressure balance connected to the CCPC as the tare gauge. This method has been successfully used for 0.1 MPa kg −1 [11], 0.2 MPa kg −1 and 0.5 MPa kg −1 CCPCs [12,13] at NMIJ. Precise measurements have revealed that d depends not only on p s but also on p j at high system pressures [5,14].…”

Section: Introductionmentioning

confidence: 99%

Methods of precisely estimating the jacket pressure coefficient of controlled-clearance piston-cylinders at pressures up to 1 GPa

Kajikawa¹,

Ide²,

Kobata³

2011

Metrologia

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Deformational characteristics of a controlled-clearance piston-cylinder (CCPC) have been evaluated to precisely estimate the pressure dependence of its effective area. Among the experimentally accessible characteristics, the jacket pressure coefficient d, which denotes the relative change in the effective area due to applied jacket pressure pj, is examined in this paper. Two methods for precisely determining d at pressures up to 1 GPa are proposed. One is a comparative method that uses a set of a pressure balance and a multiplier as the tare gauge. The other is a new method that uses precise pressure transducers as monitoring devices. Both pj and weights loaded on the CCPC are changed so that the pressure generated by the CCPC remains constant, which is monitored by the transducers. d is estimated by the relative change in the weights loaded on the CCPC itself. Using the two methods, d for a 1 MPa kg−1 CCPC is measured at pressures up to 1 GPa. At each system pressure, d obtained by each method is approximated by a linear function of pj. The consistency of the fit values of d by the two methods is confirmed. The method using pressure transducers as monitoring devices is advantageous in terms of efficiency and operability especially at higher pressures.

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Progress in development of controlled-clearance pressure balance in NMIJ

Cited by 3 publications

References 3 publications

Characteristic analysis of a controlled-clearance piston-cylinder assembly up to 1500 MPa using a finite element method

Characteristic analysis of a controlled-clearance piston-cylinder assembly up to 1500 MPa using a finite element method

ESTABLISHMENT OF THAILAND PRESSURE STANDARD FROM 1.5 kPa TO 500 Mpa

Methods of precisely estimating the jacket pressure coefficient of controlled-clearance piston-cylinders at pressures up to 1 GPa

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