• 한국원자력학회:학술대회논문집
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• 한국원자력학회 2002년도 춘계공동학술발표회요약집
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• pp.76-76
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• 2002

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 2003년도 추계학술발표대회 요약집
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• pp.201.2-201.2
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• 2003

• 한국자동차공학회논문집
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• 제6권1호
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• pp.59-72
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• 1998

This experimental study was carried out to investigate the characteristics of the in-cylinder eccentricity swirl flow generated by a 4 valve cylinder head with a tangential and a helical intake port. the measurements of the in-cylinder velocity field have been made by a two-channel LDA system. The mean flow coefficient(Cf(meam)), swirl ratio(Rs) and mass flowrate with valve eccentricity ratios and an intake port partition between the two intake ports were measured in the steady flow test fig using the ISM(impulse swirl meter). The experimental results indicated that the mass flowrate through the tangential intake port was 19% and 7.7% more than that of the helical intake port in case of with and without intake port partition respectively. There was a tendency to be a single rotation flow in swirl flow fields formed by a 4 valve cylinder head because of the interaction between the two intake ports. As the intake port partition was not set between flow coefficient(Cf(mean)) was 7.35%.

• Korean Chemical Engineering Research
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• 제40권6호
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• pp.676-680
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• 2002

기준 밀도계는 기준 조건하에서 밀도를 측정하는 기기로서, 산업계에서 특히 대유량 천연가스 계량에 폭 넓게 사용된다. 본 연구에서는 기준 밀도계의 적정 설치 및 운영방안을 제시하여 천연가스 유량 측정 정확도를 향상시키고자 현장 실험을 수행하였다. 실험 결과, 교정가스로 메탄과 질소가스 대신 메탄과 표준가스로 교정한 실험결과가 작은 밀도오차를 발생하고, 정확한 밀도 측정을 위해서는 정기적인 교정이 필수적이며, 또한 기준 밀도계는 주위 조건에 민감하게 반응하여, 주위 온도가 높으면 오차가 증가하는 것도 확인되었다.

• 한국가스학회지
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• 제27권2호
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• pp.57-64
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• 2023

가스계량기의 검침방식이 발전하면서 원격검침이 가능한 스마트 가스 계량기(누출점검용 계량기 및 다기능 안전 계량기)가 사용되고 있다. 이러한 계량기는 부가기능으로 수집하는 유량 및 압력 데이터를 활용하여 누출 판단을 하는 기능이 있다. 유량 데이터를 이용한 누출판단 기능은 실제 현장에서 유효한 사례가 있지만 압력 데이터 기반 누출 판단 기준은 누출로 인한 압력 값 변화뿐만 아니라 여러 요인(정압기 압력 크기, 인접 계량기 연계, 인접 주택 사용량, 계량기 위치 등)으로 압력 크기 변화(레벨)가 있는 문제점이 있다. 본 논문에서는 스마트 가스계량기에서 수집되는 압력데이터를 활용하여 누출여부를 판단 할 수 있는 기법으로 압력 데이터 전처리 방법과 누출 여부 관련 압력 값 범위 기준, 누출판단 기법 및 적용 사례 검증을 통해 개발하였다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 춘계학술대회논문집B
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• pp.899-905
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• 2000

The characteristics of air flow and engine performance with swirl ratio variance of intake port In a turbocharged DI diesel engine was studied in this paper. The intake port flow is important factor which have influence on the engine performance and exhaust emission because the properties in the injected fuel depend on the combustion characteristics. The swirl ratio for ports was modified by hand-working and measured by impulse swirl meter. For the effects on performance and emission, the brake torque and brake specific fuel consumption were measured by engine dynamometer and NOx, smoke were measured by gas analyzer and smoke meter. As a result of steady flow test, when the valve eccentricity ratio are closed to cylinder wall, the flow coefficient and swirl intensity are increased. And as the swirl ratio is increased, the mean flow coefficient is decreasing, whereas the gulf factor is increasing. Also, through engine test its can be expected to meet performance and emission by optimizing the main parameters; the swirl ratio of intake port, injection timing and compression ratio.

• 한국안전학회지
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• 제32권1호
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• pp.75-81
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• 2017

A series of laboratory experiments has been performed in order to investigate the behavior of water-air two-phase flow in a horizontal pipe. A conductivity meter has been applied to detect the irregular alternation of air at the specific points in flows. The experimental condition has been established according to the water and air flowrates. Passing time, which is the time length for a measuring probe to pass through the entire length of a specific bubble, has been defined to evaluate the size of bubbles in the flow. Passing length, which can be considered as the equivalent value to bubble size and determined from the product of passing time and cross-sectional averaged velocity, and its corresponding occurrence frequency have been analyzed to classify the air flow patterns according to the condition of air and water fluxes. From the result, the dependancy of flow patterns on the variation of air-water flux ratio has been investigated and the existence of thresholds also checked for classifying the behavior of air in the flow.

• 센서학회지
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• 제13권2호
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• pp.79-84
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• 2004

Asthma is one of the important respiratory diseases requiring home self care usually performed by commercialized peak expiratory flow meter (PEFM). However, this simple device can measure only single parameter, PEF, due to its purely mechanical principle, significantly limiting desease management quality. The present study introduced a new expiratory flow measurement technique by miniatured air expansion chamber easily installed within PEFM. Continuous pressure signal obtained from the chamber demonstrated an accurate quadratic relationship with flow. The volume measurement error was $<{\pm}1%$ well within the American Thoracic Society (ATS) criteria of 3%. Important spirometric parameters of FVC, PEF, and FEF25-75% were all accurately estimated with correlation coefficients > 0.95. The present technique obtains continuous expiratory air flow signal, making possible and convenient to perform spirometric test at home. Electronic interface capability would be also useful for remote asthma management.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2002년도 학술발표회 발표논문집
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• pp.53-56
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• 2002

This study presents an evaluation of the mechanical pipe flowmeter at low hydraulic heads. Three flowmeters each of 75mm and 25mm diameter were used. The Flowmeter was tested with experimental open channel apparatus. Relationship between flowmeter values and bucket values was good. The 75mm diameter flow meter showed small relative errors with hydraulic heads above 9cm. The 25mm diameter flow meter showed small relative errors with hydraulic heads above 2cm. The Irrigation flow measurement using the mechanical pipe flowmeter of 75mm diameter in paddy fields needs hydraulic head above 9cm, which is easy to get in tertiary canals.

• Journal of Advanced Marine Engineering and Technology
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• 제30권3호
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• pp.382-388
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• 2006

This study experimented to understand the effect of transporting ice slurry through in pipe with valve. And at this experiment it used ethylene glycol-water solution and a concentration is 30wt%. The experimental apparatus was constructed of ice slurry generation tank, turbo flow meter, manometers for differential pressure measuring, PIV system for flow pattern measuring. illumination and along a horizontal circular tube with valve as test section. The experiments were carried out under various conditions, with velocity of fluid at the entry ranging from 0.5 to 1.5 m/s and concentration of IPF is 30%. Also valve open rate is 50%, 75%, 100%.