Operational mode dependency on effective area for NMIJ pressure balance

Experimental methods using different pressure standards were applied to verify theoretical results obtained for the effective area of the piston-cylinder assembly (PCA) and for pressures measured with a force-balanced piston gauge (FPG). The theoretical effective area was based on the PCA’s dimensional properties defined via diameter, straightness and roundness measurements of the piston and cylinder, derived by gas-flow modelling using principles of the rarefied gas dynamics, and presented as two values: one obtained for absolute and the other for gauge pressure operation mode. Both values have a relative standard uncertainty of 5×10-6. The experimental methods chosen were designed to cover the entire operating pressure range of the FPG from 3 Pa to 15 kPa. Comparisons of the FPG with three different PTB pressure standards operated in different pressure ranges – a pressure balance, a mercury manometer and a static expansion system – were performed using the cross-float method and by a direct comparison of the generated pressures. For the theoretical and experimental effective area, as well as for pressures generated by the FPG and the reference standards, all the results demonstrated full agreement within the expanded uncertainties of the standards.

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Estimation of the effective area of the controlled-clearance pressure balance for pressures up to 500 MPa

2008 SICE Annual Conference ◽

10.1109/sice.2008.4654906 ◽

2008 ◽

Cited By ~ 2

Author(s):

Hiroaki Kajikawa ◽

Kazunori Ide ◽

Tokihiko Kobata

Keyword(s):

Effective Area ◽

Pressure Balance

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Investigation of contribution of number of trials in Monte Carlo simulation for uncertainty estimation for a pressure balance

Transactions of the Institute of Measurement and Control ◽

10.1177/01423312211039065 ◽

2021 ◽

pp. 014233122110390

Author(s):

Jasveer Singh ◽

Neha Bura ◽

Kapil Kaushik ◽

Lakshmi Annamalai Kumaraswamidhas ◽

Nita Dilawar Sharma

Keyword(s):

Monte Carlo Simulation ◽

Monte Carlo ◽

Measurement Uncertainty ◽

Critical Factor ◽

Random Number Generation ◽

Effective Area ◽

National Physical Laboratory ◽

Conventional Technique ◽

Random Numbers ◽

Pressure Balance

It is well established that the estimation of measurement uncertainty is vital for the validation of any measurement and is an essential parameter of quality assurance. Apart from the conventional technique of law of propagation of uncertainty (LPU), which has many limitations, Monte Carlo simulation (MCS) technique has become an essential tool for the estimation of measurement uncertainty in various fields of metrology. The most critical factor in MCS is the generation of random numbers of the input quantities according to their probability distributions. The number of Monte Carlo trials to generate these random numbers significantly affects the results. In particular, the required number of trials is also affected by the parameter for which the uncertainty is to be estimated. Hence, in the current paper, the effect of selection of the number of trials on the random number generation and the resulting output in terms of standard deviation (SD) is investigated for the uncertainty in the effective area of a pneumatic reference pressure standard (NPLI-4) at the CSIR-National Physical Laboratory of India. The simulation results thus obtained are compared amongst themselves, with an adaptive approach as well as with the experimental results. The outcomes are analyzed and discussed in detail.

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Water Heating and Operational Mode Switching Effects on the Performance of a Multifunctional Heat Pump

Energies ◽

10.3390/en13184896 ◽

2020 ◽

Vol 13 (18) ◽

pp. 4896 ◽

Cited By ~ 1

Author(s):

Win Jet Luo ◽

Kun Ying Li ◽

Jeng Min Huang ◽

Chong Kai Yu

Keyword(s):

Steady State ◽

Heat Pump ◽

Balance Method ◽

Mode Switching ◽

Operational Mode ◽

Water Heating ◽

Pressure Balance ◽

Pump System ◽

Heat Pump System ◽

Operational Modes

In this study, a multifunctional air and water source heat pump system was developed with a parallel refrigerant piping arrangement, which possessed six operational functions: space cooling (SC), space heating (SH), water heating (WH), water cooling (WC) and two composite operational modes. The two composite operational modes were the SC/WH mode and the SH/WH mode. The performance of the multifuctional heat pump system under different ambient conditions was investigated based on the testing standards of CNS 14464 and CNS 15466. In this study, the effect of the direct water heating (DWH) and circulating water heating (CWH) methods on the performance was investigated. It was found that the water heating performance of the system by the DWH method is better than that of the system by the CWH method. The water heating capacity and COPw,h of the DWH method can be improvement by 2.6% to 22.1% and 2.9% to 50.8%, respectively. Moreover, this study developed a refrigerant pressure balance method to achieve an effective steady state of the refrigerant pressure after operational mode switching. By the refrigerant pressure balance method, the required time to attain the steady state could be greatly reduced—by 50%. However, the deviation of the refrigerant mass flow rate between the refrigerant pressure balance method and the refrigerant pump down method after operational mode switching ranged from 0.15% to 7.6%.

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EVALUATION ON THE CONSISTENCY OF CALIBRATION RESULTS BETWEEN REFERENCE STANDARDS OF PNEUMATIC PRESSURE BALANCE BASED ON NON-FULL RANGE CALIBRATION

Jurnal Standardisasi ◽

10.31153/js.v21i3.774 ◽

2019 ◽

Vol 21 (3) ◽

pp. 203

Author(s):

Adindra Vickar Ega ◽

R.Rudi Anggoro Samodro

Keyword(s):

High Pressure ◽

Pressure Range ◽

Full Range ◽

Effective Area ◽

National Metrology Institute ◽

Pressure Balance ◽

Pneumatic Pressure ◽

Piston Cylinder ◽

Normalized Error ◽

High Pressure Range

To provide calibration services for pressure measuring devices, SNSU-BSN has several piston-cylinder standard that may traceable to different National Metrology Institute (NMIs). Non-full range calibration of pressure balance has been performed to evaluate the consistency of calibration results between those standard, especially for establishing self-traceability in the future. In this research, a piston-cylinder unit S/N 1926 with medium pressure range of 1750 kPa, was calibrated with low pressure range S/N 978 of 350 kPa and high pressure range S/N 1054 of 7000 kPa. The calibration was performed with cross-float method to evaluate the effective area of piston-cylinder at null pressure and reference temperature of 20⁰C (A0,20) and distortion coefficient (λ) as the 1926 main parameters. The obtained value, respectively are (1.961 166 × 10-4 ± 4.4 × 10-9) m2 and (-1.67 × 10-12 ± 9.4 × 10-13) Pa-1 from 978 and (1.961166 × 10-4 ± 5.1 × 10-9) m2 and (-1.58 × 10-12 ± 8.4 × 10-13) Pa-1 from 1054. The result of 1926 from both methods shows good conformity with Normalized Error (En) of 0.0007 and 0.069, respectively. Linearity of effective area changes to the pressure is very consistent in both low and high pressure range. Validation results by using PTB-Germany results, shows the relative different for A0 and λ obtained are less than 0,1 × 10-6 and 6%,respectively. Therefore, the pneumatic pressure balance of SNSU-BSN is traceable, consistent with each other and capable for disseminating the pressure unit along all primary pressure standard owned with high agreement compared to those of other advance NMIs.

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Rarefied gas flow in pressure and vacuum measurements

ACTA IMEKO ◽

10.21014/acta_imeko.v3i2.101 ◽

2014 ◽

Vol 3 (2) ◽

pp. 60 ◽

Cited By ~ 6

Author(s):

Jeerasak Pitakarnnop

Keyword(s):

Gas Flow ◽

Rarefied Gas ◽

Slip Flow ◽

Effective Area ◽

Low Flow ◽

Vacuum System ◽

Rarefied Gas Flow ◽

Pressure Balance ◽

Piston Cylinder ◽

Flow Leak

Flows of a gas through the piston-cylinder gap of a gas-operated pressure balance and in a general vacuum system have one aspect in common, namely that the gas is rarefied due, respectively, to the small dimensions and the low pressure. The flows in both systems could be characterised as being in either slip-flow or transition regimes. Therefore, fundamental research of flow in these regimes is useful for both pressure and vacuum metrology, especially for the gas-operated pressure balance where a continuum viscous flow model is widely used for determining the effective area of the pressure balance. The consideration of gas flow using the most suitable assumption would improve the accuracy of such a calculation. Moreover, knowledge about rarefied gas flow will enable gas behaviour in vacuum and low-flow leak detection systems to be predicted. This paper provides useful information about rarefied gas flow in both slip-flow and transition regimes.

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