• 대한기계학회논문집B
• /
• 제25권4호
• /
• pp.561-571
• /
• 2001

The standard uncertainty of flowrate measurement is obtained by combining that of independent variables. Gravimetric and volumetric method were applied to determine the flowrate and the standard uncertainties of flowrate measurement by both methods were evaluated in accordance with the procedure recommended by International Organization for Standardization. The combined standard uncertainties of determining the flowrate were estimated from the sensitivity coefficient and the standard uncertainty of independent variables. For practical application, the methods for evaluating and expressing uncertainty in flow measurement were discussed. It was found that the uncertainties of the weighing and time measurement in gravimetric method, the volume and time measurement in volumetric method have dominant influence on that of flowrate measurement. With the quantitative analysis of the sensitivity coefficient, the contribution of the each variable uncertainty to the combined standard uncertainty of flowrate measurement is shown clearly.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 1991년도 한국자동제어학술회의논문집(국제학술편); KOEX, Seoul; 22-24 Oct. 1991
• /
• pp.1712-1717
• /
• 1991

The paper describes estimation errors of unsteady flowrate measurements due to parameter changes in a quasi-remote instantaneous flowrate measurement method (abbreviate as QIFM) and an instantaneous flowrate measurement method using two points pressure measurements (abbreviate as TPFM). By introducing error performance index, the influence of parameter changes on the accuracy, and dynamic response of the estimated unsteady flowrate are evaluated. Of four parameters, the variation of the length of the pipeline and speed of sound produce large errors in the estimated unsteady flowrate during transient periods. The effect of kinematic viscosity of the working fluid(oil) is relatively insensitive in unsteady flowrate estimation.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 1989년도 한국자동제어학술회의논문집; Seoul, Korea; 27-28 Oct. 1989
• /
• pp.749-754
• /
• 1989

This paper describes a remote measurement method for estimating unsteady flowrate through a pipeline. By this method, instantaneous flowrate at the remote location along a pipeline (distance L) from flowmeters is measured by making use of dynamic characteristics between two cross sections of the circular pipeline. Using this method, instantaneous flowrate is accurately measured at a location where it is difficult to setup flowmeters. The estimated flowrate waveforms by the method are compared with directly measured ones by cylindrical choke-type instantaneous flowmeter. The validity of the method is established.

• Journal of Advanced Marine Engineering and Technology
• /
• 제9권4호
• /
• pp.339-347
• /
• 1985

Precise measurement of flowrate is considered as an important measuring factor in mechanical and chemical experiment. Although there are many methods to measure flowrate, Float type flowmeter is widely used because of its easy attachment to piping and high measuring precision. To design the precise float type flowmeter, much design information such as tapered-tube dimensions, float size, float shape and float material is required. In this paper, fundamental design theory for float type flowmeter according to the given flowrate range is suggested and compensation coefficients of volumetric and weight flowrate for water, R-113 and air are calculated.

• 대한기계학회논문집
• /
• 제16권5호
• /
• pp.933-942
• /
• 1992

본 연구에서는 이상류 동축 노즐의 미립화 기구를 규명하기 위한 기초단계로 20˚의 증류수를 사용하여 이상류 동축노즐의 평균액적 직경에 미치는 공급유량의 영 향을 직접사진 촬영법을 사용하여 규명하고자 한다.

• 유체기계공업학회:학술대회논문집
• /
• 유체기계공업학회 2003년도 유체기계 연구개발 발표회 논문집
• /
• pp.373-378
• /
• 2003

In this paper, build up of fan performance tester in KITECH was introduced. The fan tester was set up based on AMCA standards 210-99, ANSI/ASHRAE 51-1999 with maximum flowrate within $1000\;m^{3}/min$. Both of inlet and outlet chamber setup with multiple nozzles described in AMCA 210 were established. The development of fully automatic control and measurement system are described. With this system, the accuracy of fan performance test can be maintained through the various flowrate and the uncertainty can be reduced.

• Journal of Biosystems Engineering
• /
• 제11권2호
• /
• pp.88-91
• /
• 1986

• 대한기계학회논문집B
• /
• 제28권10호
• /
• pp.1219-1230
• /
• 2004

Comparing to the gravimetric and volumetric method, the flowmeter calibration based on the master meter method is relatively economical and convenient, especially for high flowrate. The uncertainty of flow quantity and flowrate using the master meter method was evaluated according to the GUM (Guide to the Expression of Uncertainty in Measurement). In order to apply for the wider flow range, two master meters (electromagnetic flow meter) were employed as reference flowmeters. The uncertainty of the master meter was obtained by combining the statistical variation of the repeated measurements and the variation of fluid density and pipe material due to temperature and pressure changes were scrutinized. for a practical application, the uncertainty of calibrator, whose measuring capacity of 1000 ㎥/h obtained by employing two 500 ㎥/h electromagnetic How meters, was evaluated. The uncertainty budget shows the quantitative contribution of each uncertainty component to the overall uncertainty of the calibrator. As a result, it was found that the dominant uncertainties were from the master meter, which was evaluated statistically, and from the process of least squares fitting. On the contrary, the uncertainties arising from the variation of the fluid density and the pipe volume due to the temperature and pressure were negligible.

• 대한기계학회논문집
• /
• 제10권3호
• /
• pp.335-342
• /
• 1986

본 연구에서는 이러한 가능성을 알아 보기 위하여 오리피스판을 통하여 기액 2상흐름이 있을 때 각 상의 유량변화레 따른 순간압력강하치를 분석하고자 한다. 우선 평균압력강하치를 측정하여 식 (1)과 비교 분석하며, 교란치의 평균진폭과 교란 강도를 구하여 기공율의 변화에 따른 이러한 통계치들의 경향을 고찰한다. 그리고 순간압력강하 곡선에 대한 통계함수들, 확률밀도함수(probability density function) 와 자기상관함수(auto-correlation function)을 구하여 이 들의 통계적 성질을 구명 하고 2상 유동량의 결정에 대한 교란치의 할동도를 토의한다.

• 한국유체기계학회 논문집
• /
• 제3권3호
• /
• pp.25-30
• /
• 2000

Thermodynamic method of pump performance measurement calculates pump efficiency and flowrate by measuring fluid temperature increase and pressure rise through the pump. The theory of this method is investigated and precise comparison experiment with classical hydraulic method was conducted to verify the accuracy. Classical hydraulic pump performance measurement results and Yatesmeter results based on the thermodynamic method showed good agreement in measured performance.