• 대한기계학회논문집B
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• 제24권10호
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• pp.1388-1398
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• 2000

A pipe prover is a flowmeter calibrator used in flow measurement field. Gravimetric and volumetric methods were applied to determine the basic volume of the pipe prover. Uncertainty of its basic volume measurement was evaluated in accordance with the procedure recommended by International Organization for Standardization. The combined standard uncertainty of determining the basic volume was estimated from the sensitivity coefficient and the standard uncertainty of independent variables. It was found that the uncertainties of the weighing and volume measurements have dominant influence on that of the basic volume determination. With the quantitative analysis of the sensitivity coefficient, the contribution of the each variable uncertainty to the combined standard uncertainty of the basic volume is shown clearly.

• 대한기계학회논문집B
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• 제32권9호
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• pp.712-719
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• 2008

Light Oil Flow Standard System(LOFSS), as a national oil flow standard system, in Korea Research Institute of Standards and Science(KRISS) was developed for oil flowmeter calibration, and the expanded uncertainty of flow quantity determination was estimated within 0.04 %. In order to improve the reliability of the LOFSS measurement, a proficiency test was carried out in the flow range of 20 and $240\;m^3/h$ (Reynolds number $20,000{\sim}900,000$). A turbine flowmeter was used as a transfer package in round robin test. The water flow standard system of KRISS, the pipe prover of the national calibration and test organization and the master meter calibrator of the turbine flowmeter supplier, which used the different working fluid respectively, were compared with the turbine flowmeter measurement. The maximum difference of measurement was 0.15 % between the LOFSS and the pipe prover. The En numbers of the each system measurement were evaluated at the same Reynolds number. It was found that the En numbers were less than 1 in the comparison, which means the procedures of the uncertainty estimation of the each calibrators were reasonable and reliable.

• 물과 미래
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• 제26권4호
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• pp.97-105
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• 1993

본 논문은 캡슐밀도의 균일성의 영향을 고려하여 관로내에서의 원통형 캡슐 흐름의 특성을 이해하기 위하여 수행된 연구결과를 기술한다. 캡슐의 중심 축방향으로의 밀도변화 영향을 실험적으로나 분석적인 방법으로 연구하였다. 실험은 직경 190mm, 길이 17m인 관에서 수행되었으며, 속도, 캡슐의 기울기, 캡슐바닥과 관과의 간격이 여러 가지 실험 조건하에서 측정되었다. 실험데이타를 해석하기 위하여 무차원 변수로 주어지는 안정성지수(Stability Index)가 유도되었다. 관로에서의 캡슐의 거동은 안정성 지수에 크게 영향을 받는다. 실험결과는 안정성 지수가 캡슐거동과 캡슐밀도의 균일성과의 상관관계를 잘 설명하여주는 유효한 기준임을 증명하였다.

• 한국유체기계학회 논문집
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• 제20권1호
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• pp.59-64
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• 2017

Diverter is an essential element in gravimetric calibration method of flowmeter. Error of diverter are influenced by flow velocity profile of nozzle outlet, motion velocity of diverter and detecting location. That's why, time detection position of diverter is tuned through repetitive test for minimizing error of diverter. Further the diverter must be compared with the other institutions test since the influence on the accuracy of the flow meter used in the test. In this paper, errors (flow velocity profile of nozzle outlet, motion velocity of diverter and detecting location) of diverter are decreased by produced uni-direction diverter and error of gravimetric calibration system is decreased. Uni-direction diverter is calibrated by gravimetric calibration system with precision flowmeter, the flowmeter is calibrated by pipe prover and other institutions and uni-direction diverter is evaluated. Uni-direction diverter is not influenced by flow velocity profile of nozzle outlet, motion velocity of diverter and detecting location. As a result, Uni-direction diverter can calibrate in wider scope since increasing ratio of maximum and minimum flow rate of uni-direction diverter.