• 제목/요약/키워드: gas measurement method

검색결과 641건 처리시간 0.028초

기체 유량 측정에서 몬테 카를로 모사를 이용한 측정불확도 평가 (Uncertainty Assessment Using Monte Carlo Simulation in Gas Flow Measurement)

  • 이대성;양인영;김춘택;양수석
    • 대한기계학회논문집B
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    • 제27권12호
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    • pp.1758-1765
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    • 2003
  • Monte Carlo simulation(MC) method was used as an uncertainty assessment tool for gas flow measurement in this paper. Uncertainty sources for gas flow measurement were analyzed, and probability distribution characteristics of each source were discussed. Detailed MC methodology was described including the effect of the number of simulation. The uncertainty result was compared with that of the conventional sensitivity coefficient method, and it was revealed that the results were different from each other for this particular gas flow measurement case of which the modelling equation was nonlinear. The MC was comparatively simple, convenient and accurate as an uncertainty assessment method, especially in cases of complex, nonlinear measurement modelling equations. It was noted that the uncertainty assessment method should be selected carefully according to the mathematical characteristics of the measurement.

다점 피토관을 이용한 기체 유량 측정의 불확도 평가 (Uncertainty Assessment of Gas Flow Measurement Using Multi-Point Pitot Tubes)

  • 양인영;이보화
    • 한국유체기계학회 논문집
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    • 제19권2호
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    • pp.5-10
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    • 2016
  • Gas flow measurement in a closed duct was performed using multi-point Pitot tubes. Measurement uncertainty was assessed for this measurement method. The method was applied for the measurement of air flow into a gas turbine engine in an altitude engine test facility. 46 Pitot tubes, 15 total temperature Kiel probes and 9 static pressure tabs were installed in the engine inlet duct of inner diameter of 264 mm. Five tests were done in an airflow range of 2~10 kg/s. The flow was compressible and the Reynolds numbers were between 450,000 and 2,220,000. The measurement uncertainty was the highest as 6.1% for the lowest flow rate, and lowest as 0.8% for the highest flow rate. This is because the difference between the total and static pressures, which is also related to the flow velocity, becomes almost zero for low flow rate cases. It was found that this measurement method can be used only when the flow velocity is relatively high, e.g., 50 m/s. Static pressure was the most influencing parameter on the flow rate measurement uncertainty. Temperature measurement uncertainty was not very important. Measurement of boundary layer was found to be important for this type of flow rate measurement method. But measurement of flow non-uniformity was not very important provided that the non-uniformity has random behavior in the duct.

무선센서네트워크 기반 공기질 측정을 위한 비분산적외선 복합가스측정시스템 (NDIR Multi-Gas Measurement System for Air Quality based on Wireless Sensor Network)

  • 백승현;이준영;정상우;박홍배
    • 대한임베디드공학회논문지
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    • 제11권5호
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    • pp.299-304
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    • 2016
  • As public interest in air quality and environment problem is increasing, many researches are being carried out the gas measurement system. Especially, Non-dispersive infrared (NDIR) measurements using Beer-Lambert gas sensing principle with very high selectivity and long life time are noted for reliable method. It is possible to detect various gases such as carbon dioxide (CO2), carbon monoxide (CO), and nitrogen dioxide (NO2), but many researches are mostly concentrated on CO2 sensor. The multi-gas measuring instrument is high price and unwieldy, therefore it is not suitable for wide area required numerous instrument. So we study the NDIR multi-gas measurement system for air quality based on wireless sensor network, and experiment the realized measurement system.

고압수소 유량계측용 임계노즐 유동의 수치해석적 연구 (A Computational Work of Critical Nozzle Flow for High-Pressure Hydrogen Gas Mass Flow Measurement)

  • 이준희;김희동;박경암
    • 유체기계공업학회:학술대회논문집
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    • 유체기계공업학회 2006년 제4회 한국유체공학학술대회 논문집
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    • pp.227-230
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    • 2006
  • The method of mass flow rate measurement using a critical nozzle is well established in the flow satisfying ideal gas law. However, in the case of measuring high-pressure gas flow, the current method shows invalid discharge coefficient because the flow does not follow ideal gas law. Therefore an appropriate equation of state considering real gas effects should be applied into the method. The present computational study has been performed to give an understanding of the physics of a critical nozzle flow for high-pressure hydrogen gas and find a way for the exact mass flow prediction. The two-dimensional, axisymmetric, compressible Navier-Stokes equations are computed using a fully implicit finite volume method. The real gas effects are considered in the calculation of discharge coefficient as well as in the computation. The computational results are compared with the previous experimental data and predict well the measured mass flow rates. It has been found that the discharge coefficient for high-pressure hydrogen gas can be corrected properly adopting the real gas effects.

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아세톤 PLIF를 이용한 가스터빈 연소기 버너 출구 연료분포의 정량적 측정 (Quantitative Acetone PLIF Measurement of Fuel Distribution in a Gas Turbine Combustor Burner)

  • 전우진;김형모;이강엽;양수석
    • 한국연소학회지
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    • 제15권4호
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    • pp.43-52
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    • 2010
  • A non-intrusive measurement, Planar Laser Induced Fluorescence was employed to visualize and measure the fuel distribution of the non-reacting field at the burner exit of gas turbine combustor. Measurement techniques, image processing method and quantification procedure were presented. Also, concentration measurement with gas analyzer was carried out to verify the propriety of PLIF result. The PLIF result coincides well with gas analyzer measurement result. PLIF test result for several other conditions are mentioned as well.

몬테카를로 방법과 ISO-GUM 방법의 불확도 평가 결과 비교 (Comparison of ISO-GUM and Monte Carlo Method for Evaluation of Measurement Uncertainty)

  • 하영철;허재영;이승준;이강진
    • 대한기계학회논문집B
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    • 제38권7호
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    • pp.647-656
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    • 2014
  • 본 연구에서는 ISO GUM(불확도 표현 지침서)의 불확도 평가 방법을 보완하기 위해, 몬테카를로 방법(Monte Carlo Method, MCM)을 적용한 불확도 해석 프로그램을 개발하고, MCM과 GUM의 평가 결과를 비교하였다. 그 결과 다음과 같은 결과를 도출하였다. 첫째, 측정량의 확률 분포가 정규 분포가 아닌 때에도 MCM 방법은 정확한 포함 구간을 제공한다. 둘째, 정규 분포가 아닌 다른 분포들 몇몇 개가 합성되는 경우 그 확률 분포가 정규로 보이더라도 실제로는 정규가 아닌 경우가 있으며, 이의 판단은 합성 분산의 확률 분포로 할 수 있다. 셋째, 자유도가 낮은 A형 불확도가 불확도 평가에 포함된 경우 GUM은 포함 구간을 저평가하는 것을 알 수 있었고, 이러한 저평가 문제는 A형 표준 불확도에 t-분포의 표준 편차를 곱해주면 사라지는 것을 알 수 있었다. 이 경우 합성 분산의 유효 자유도는 확장 불확도 계산에 불필요하고, 신뢰의 수준 95 %의 포함 인자는 1.96이 적정한 것을 알 수 있었다.

기체용적계를 이용한 분동식 압력계용 기준분동의 새로운 부피측정 방법 (New Method of Volume Measurement for Reference Weights of a Pressure Balance Using a Gas Pycnometer)

  • 이용재;이우갑;모하메드;박연규;오재윤
    • 한국진공학회지
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    • 제22권5호
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    • pp.231-237
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    • 2013
  • 본 연구에서는 분동식 기준압력계의 기준분동(reference weight)의 부피를 측정하는 새로운 측정방법인 기체용적계(gas pycnometer) 측정방법을 제안하였다. 제안된 측정방법에 의한 측정결과로서 기준분동 1 kg, 2 kg, 5 kg에 대한 부피 측정불확도는 신뢰수준 95%에서 0.2%를 나타내었다. 기체용적계의 주요 장치는 샘플용기와 팽창용기, 정밀압력계, 정밀온도계, 진공펌프로 구성되며, 측정 원리는 일정한 용기 내에 들어 있는 일정한 양의 기체의 압력과 부피는 서로 반비례한다는 보일(boyle's law)의 법칙을 용용하였다. 본 결과는 현재까지 문헌이나 제조사로부터 기준분동 재질에 대한 밀도값을 적용하여 오던 것을 기준분동의 부피를 직접 측정하여 밀도값을 적용함으로서 압력기준기의 압력 기준값에 대한 국가측정표준의 신뢰도 향상에 기여될 것이다.

공동주택 욕실 배기팬의 플랙시블 덕트 시공상태에 따른 환기효율에 관한 연구 (A Study on the Ventilation Efficiency of Apartment Housing Bathroom Based on the Flexible Installation Method of Exhaust Fan.)

  • 이광명;함진식
    • 한국주거학회논문집
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    • 제16권1호
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    • pp.73-79
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    • 2005
  • The ventilation efficiency of apartment housing bathroom has been measured by the flexible's diameter, length, and installation format to the exhaust In. The gas density attenuation method of Tracer Gas Method has been specifically utilized for this measurement. Full size mock-up of apartment housing bathroom, which was approximately $100 m^2$ in size, has been established for the ventilation emciency measurement. In addition, the ventilation efficiency has been studied by the possibility of air-supply In. The diameters of flexible are 100 mm, 125 mm, and 150mm. It also have the length of 1.0m, and 1.5 m. The installation formats are I shape, L shape, and S shape. As a result of this measurement, the flexible which has the highest ventilation efficiency was the one has bigger diameter, short in length, and I shape installation format.

마이크로 스케일의 흡수선과 흡수강도를 이용한 분무화염의 온도측정 (Temperature measurement of the spray flame using micro scale absorption bands and line strength)

  • 최경민
    • 한국분무공학회지
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    • 제7권2호
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    • pp.1-6
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    • 2002
  • It is necessary to develope a high frequency diode laser sensor system based on the absorption spectroscopy for the measurement of temperature of the spray flame. DFB diode laser operating near $2.0{\mu}m$ was used to scan over selected $H_2O$ transitions near $1.9{\mu}m\;and\;2.2{\mu}m$, respectively. The measurement sensitivity at wide range of sweep frequency was evaluated using multi-pass cell containing $CO_2$ gas. This diode laser absorption sensor with high temporal resolution up to 10kHz was applied to measure the gas temperature in the spray flame region of liquid-gas 2-phase counter flow flame. The successful demonstration of time series temperature measurement in the spray flame gives us motivation of trying to establish non-intrusive temperature measurement method in the practical spray flame.

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소닉노즐을 이용한 천연가스 유량측정에서 임계유동인자 계산 및 국제비교 결과 (Evaluation of Critical Flow Factor in Natural Gas Flow Measurement Using Sonic Nozzle and International Comparison Results)

  • 하영철;허재영
    • 대한기계학회논문집B
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    • 제23권7호
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    • pp.911-917
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    • 1999
  • The sonic nozzle is widely used as reference device for calibrating flowmeters In gas flow measurement and its use requires the Critical Flow Factor(CFF) based on the thermodynamic properties of the gas at the nozzle throat. ISO-9300 provides the calculating method of the factor. But since the CFF from this method show an error over ${\pm}0.5%$ In specific conditions and of ${\pm}0.1{\sim}{\pm}0.2%$ in common Natural Gas(NG) custody transfer condition. this method cannot be applied for gas flow measurement with sonic nozzle. Each research bodies or organizations of the world have joined in order to calculate the CFF more accurately. They have performed these works using their own method and compared the results with each other under the management of ISO. KOGAS have joined those works, because the high-pressure natural gas flow calibration facility of KOGAS will be constructed in late 1999, and then had necessities to calculate a CFF accurately. The calculation method of KOGAS was using the equation of state from AGA-8('94), high accuracy model of ideal gas properties and the solutions of thermodynamic equations. The evaluation results have had a very good consistency within ${\pm}0.05%$ in most NO custody transfer conditions compared to the speed of sound for methane and also shown that the CFF was within ${\pm}0.1%$ compared to the results of other works of the world.