• 제목/요약/키워드: mass flow sensor

검색결과 64건 처리시간 0.024초

SCV를 장착한 2밸브 Sl 가시화기관의 연소특성에 관한 연구 (A Study of the Combustion Characteristics Using a 2-valve Sl Optically Acessible Engine with SCV)

  • 정구섭;전충환;장영준
    • 대한기계학회논문집B
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    • 제25권12호
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    • pp.1692-1701
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    • 2001
  • This study describes the combustion characteristics under various condition of air excess ratio and ignition timing in a 2-valve SI optically accessible engine with swirl control valve(SCV). It adapted three different types of SCV(open ratio 72.5%, 78%, 59%) to strengthen a swirl flow. Pressure data were acquired using pressure sensor to investigate the effect of swirl flow on combustion, and from these pressure data, IMEP(indicated mean effective pressure) and MFB(mass fraction burnt) were calculated to explain burn rate and flame speed. From acquired flame images, we inspected the flame propagation direction, flame area, and flame centroid. Flame propagation direction showed different tendency between with/without SCV, and flame area with SCV was faster and larger than that of conventional engine. Finally, the representative flame images at each crank angle were acquired by PDF method to verify flame growth process. It is found that strengthened swirl flow is more beneficial for faster and stable combustion.

베이즈 분류기를 이용한 수냉식 냉동기의 고장 진단 방법에 관한 실험적 연구 (An Experimental Study on Fault Detection and Diagnosis Method for a Water Chiller Using Bayes Classifier)

  • 이흥주;장영수;강병하
    • 대한설비공학회:학술대회논문집
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    • 대한설비공학회 2008년도 하계학술발표대회 논문집
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    • pp.36-41
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    • 2008
  • Fault detection and diagnosis(FDD) system is beneficial in equipment management by providing the operator with tools which can help find out a failure of the system. An experimental study has been performed on fault detection and diagnosis method for a water chiller. Bayes classifier, which is one of classical pattern classifiers, is adopted in deciding whether fault occurred or not. FDD algorithm can detect refrigerant leak failure, when 20% amount of charged refrigerant for normal operation leaks from the water chiller. The refrigerant leak failure caused COP reduction by 6.7% compared with normal operation performance. When two kinds of faults, such as a decrease in the mass flow rate of cooling water and temperature sensor fault of cooling water inlet, are detected, COP is a little decreased by these faults.

  • PDF

MFC의 퍼지제어기 구현 (Implementation of Fuzzy Controller for MFC)

  • 이석기;이연정;이승하
    • 한국지능시스템학회논문지
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    • 제14권5호
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    • pp.648-654
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    • 2004
  • 반도체 제조 장비에서 가스의 질량 흐름 제어기(Mass Flow Controller: MFC)가 차지하는 비중은 매우 크다. 가스의 흐름 제어가 곧 반도체 소자의 품질 및 수율을 결정하는 중요한 요소이기 때문이다. 따라서 MFC의 고속, 고정밀 제어를 구현하기 위한 요구가 높아지고 있다. MFC의 제어 알고리즘에 관한 연구 선례는 찾아보기가 매우 힘들다. 그러나 일반적으로 PID 제어 알고리즘을 사용되는 것으로 알려지고 있다. MFC 제어의 어려움은 열에 의해 흐름을 감지하는 시스템일 경우 느린 응답 특성과 비선형성을 포함한다는 데 있다. 본 논문에서는 기존의 PID 알고리즘 보다 더 우수한 성능을 보이는 MFC 제어 알고리즘을 제시하고 실험을 통해 그 우수성을 보인다. 비선형성과 느린 응답 특성을 보상하기 위하여 퍼지제어 알고리즘을 적용하였으며 그 성능을 현재 상용화된 제품과 비교하였다. 본 논문에서 제안한 알고리즘은 PC와 PC에 장착된 데이터 획득 보드를 통하여 제어루프를 형성하였고, PC상에서 LabWindows/CVI 프로그램으로 제어알고리즘을 구현하였다. 또한, 느린 응답 특성이 존재하는 센서출력으로부터 실제의 흐름을 추정하는 하나의 방법도 제시하였다. 실험결과 본 논문에서 제안하는 알고리즘이 기존의 제품보다 더 빠르고, 더 정확한 제어성능을 보였다.

SnO2를 이용한 CO 및 NOx 가스 감지 센서 제작 및 특성 연구 (Fabrication and Evaluation of the SnO2 Based Gas Sensor for CO and NOx Detection)

  • 김만재;이유진;안효진;이상훈
    • 한국자동차공학회논문집
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    • 제23권5호
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    • pp.515-523
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    • 2015
  • In this paper, we fabricated and evaluated the gas sensor for the detection of CO gas and $NO_X$ gas among the vehicle exhaust emission gasses. The $SnO_2$ (tin dioxide) layer is used as the detection material, and the thin-film type and the nano-fiber type layers are deposited with various thicknesses using sputtering method and electro spinning method, respectively. The experiments are performed in the chamber where the gas concentration is controlled with mass flow controller. The fabricated devices are applied to the CO and $NO_X$ gas, where the device with the thinner $SnO_2$ layer shows better sensitivity. The nano-fiber has the larger surface area, and the shorter response time and recovery time are obtained. From the experimental results, both types of gas sensors successfully detect CO and $NO_X$ gases, which can be applied to measure those gases from the vehicle emissions.

Use of In-Situ Optical Emission Spectroscopy for Leak Fault Detection and Classification in Plasma Etching

  • Lee, Ho Jae;Seo, Dong-Sun;May, Gary S.;Hong, Sang Jeen
    • JSTS:Journal of Semiconductor Technology and Science
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    • 제13권4호
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    • pp.395-401
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    • 2013
  • In-situ optical emission spectroscopy (OES) is employed for leak detection in plasma etching system. A misprocessing is reported for significantly reduced silicon etch rate with chlorine gas, and OES is used as a supplementary sensor to analyze the gas phase species that reside in the process chamber. Potential cause of misprocessing reaches to chamber O-ring wear out, MFC leaks, and/or leak at gas delivery line, and experiments are performed to funnel down the potential of the cause. While monitoring the plasma chemistry of the process chamber using OES, the emission trace for nitrogen species is observed at the chlorine gas supply. No trace of nitrogen species is found in other than chlorine gas supply, and we found that the amount of chlorine gas is slightly fluctuating. We successfully found the root cause of the reported misprocessing which may jeopardize the quality of thin film processing. Based on a quantitative analysis of the amount of nitrogen observed in the chamber, we conclude that the source of the leak is the fitting of the chlorine mass flow controller with the amount of around 2-5 sccm.

차량 연료 소모량 예측을 위한 신경회로망 기반 모델링 (Neural Network-Based Modeling for Fuel Consumption Prediction of Vehicle)

  • 이민구;정경권;이상회
    • 전자공학회논문지 IE
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    • 제48권2호
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    • pp.19-25
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    • 2011
  • 본 논문에서는 연료 소모량을 예측하기 위해 차량 데이터를 이용한 신경회로망 모델링 방식을 제안하였다. 제안한 신경회로망의 훈련과 시험 데이터를 획득하기 위해 시내를 중형 가솔린 차량을 주행하였고, OBD-II 포트에서 입력 데이터로 속도, 엔진 RPM, 쓰로틀 위치 센서(TPS), 흡기 공기량(MAF)을 측정하였고, 목표값으로 연료 소모량을 측정하였다. 입력과 출력 데이터의 빈선형 맵핑을 위해 다층 퍼셉트론 네트워크를 사용하였다. 신경회로망 모델은 평균 제곱오차가 $1.306{\times}10^{-6}$로 연료 소모량을 매우 잘 예측함을 확인하였다.

미세먼지 간이측정기 현장 검사용 시험 입자 발생기 개발 및 성능 평가 (Development and performance evaluation of a test particle generator for a field inspection equipment of PM-2.5 sensors)

  • 정혁;박진수
    • 한국입자에어로졸학회지
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    • 제18권3호
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    • pp.61-68
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    • 2022
  • In this study, a fluidized bed particle generator was developed to generate an aerosol without supply of compressed air and to increase portability. It was assumed that the mixing ratio of the test particles and beads, the input amount, and the air flow rate supplied to the generator would have effect on the aerosol generation characteristics. The product of these three parameters was set as a characteristic parameter and particle generation characteristics according to the change of the characteristic parameter were observed. As a result, it was confirmed that the input amount of test particles and beads was not suitable as a characteristic parameter and a characteristic parameter expressed as a product of the mass mixing ratio and the air flowrate was newly defined. When the new characteristic parameter is applied, it can be confirmed that the total amount of particles generated from the particle generator is a function of the characteristic parameter. As a result of measuring the amount of particle generation by adjusting the characteristic parameter, it was confirmed that the performance required for the test particle generator for the field inspection equipment of PM-2.5 sensors could be satisfied.

기체 에틸렌/산소 Tri-arc 회전 데토네이션 엔진 실험연구 (An Experimental Study of Tri-arc Rotating Detonation Engine Using Gaseous Ethylene/Oxygen)

  • 이은성;한형석;최정열
    • 한국추진공학회지
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    • 제25권1호
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    • pp.19-28
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    • 2021
  • 회전 데토네이션 엔진(Rotating Detonation Engine, RDE)은 기계 장치나 유동이 아닌 데토네이션 파만이 연소실 벽을 따라 회전한다. 따라서 RDE 단면이 원형이어야 할 필요가 없으며 임의 단면의 닫힌 형상이 가능하다. 본 연구에서는 임의의 단면을 가지는 RDE의 한 가지 예로써 tri-arc 단면 형상의 RDE를 설계하였으며, 실험적으로 작동 및 성능 특성을 살펴보았다. 동압 센서와 고속카메라를 통하여 데토네이션 파의 회전을 확인하였으며, 오목 면과 볼록 면에서 질량 유량에 따른 데토네이션파의 특징을 알아보았다. 본 연구에서는 유량 조건에 따라 17.0 N에서 96.0 N의 추력 수준을 얻을 수 있었다.

기관지확장제 사용 후 시간에 따른 폐활량 측정치의 변화 (The Time Responses of Spirometric Values in Response to Single Doses of Inhaled Salbutamol)

  • 박순효;최원일;이상원;박훈표;서용우;구덕희;이미영;이충원;전영준
    • Tuberculosis and Respiratory Diseases
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    • 제56권2호
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    • pp.144-150
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    • 2004
  • 연구배경 및 목적 : 기류가역성의 유무와 정도의 평가는 기도질환 환자의 진단 및 치료에 있어서 매우 중요하지만, 기관지확장제 사용 후 기류 가역성을 관찰하기 위한 적절한 폐기능 검사 시간과 폐활량 측정치의 변화에 대한 연구는 매우 적다. 따라서 본 연구는 기관지확장제 사용 후 시간에 따른 폐활량 측정치의 변화를 분석하고자 하였다. 방 법 : 천식 환자 15명을 대상으로 salbutamol $200{\mu}g$을 일 회 흡입 후 15, 30, 45, 60분에 mini-Wright 유량측정기 및 폐활량검사를 이용하여 기관지확장제 반응을 측정하였다. 결 과 : $FEV_1$ 과 FVC의 평균값은 기관지확장제 사용 후 60분에 가장 높게 관찰 되었다. 폐활량 측정치 및 mini-Wright유량측정계의 두 측정치에서 PEF의 평균값은 기관지확장제 사용 후 45분에 가장 높게 관찰되었다. 결 론 : 이상의 결과로서 기류폐색이 의심되는 환자에서 기류가역성을 평가할 때 salbutamol 사용 후 15분 보다는 45분 내지 60분에 PEF 또는 $FEV_1$을 측정하는 것이 기관지확장제 반응을 적절히 평가할 것으로 사료된다.

설비공학 분야의 최근 연구 동향 : 2013년 학회지 논문에 대한 종합적 고찰 (Recent Progress in Air-Conditioning and Refrigeration Research : A Review of Papers Published in the Korean Journal of Air-Conditioning and Refrigeration Engineering in 2013)

  • 이대영;김사량;김현정;김동선;박준석;임병찬
    • 설비공학논문집
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    • 제26권12호
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    • pp.605-619
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    • 2014
  • This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2013. It is intended to understand the status of current research in the areas of heating, cooling, ventilation, sanitation, and indoor environments of buildings and plant facilities. Conclusions are as follows. (1) The research works on the thermal and fluid engineering have been reviewed as groups of fluid machinery, pipes and relative parts including orifices, dampers and ducts, fuel cells and power plants, cooling and air-conditioning, heat and mass transfer, two phase flow, and the flow around buildings and structures. Research issues dealing with home appliances, flows around buildings, nuclear power plant, and manufacturing processes are newly added in thermal and fluid engineering research area. (2) Research works on heat transfer area have been reviewed in the categories of heat transfer characteristics, pool boiling and condensing heat transfer and industrial heat exchangers. Researches on heat transfer characteristics included the results for general analytical model for desiccant wheels, the effects of water absorption on the thermal conductivity of insulation materials, thermal properties of Octadecane/xGnP shape-stabilized phase change materials and $CO_2$ and $CO_2$-Hydrate mixture, effect of ground source heat pump system, the heat flux meter location for the performance test of a refrigerator vacuum insulation panel, a parallel flow evaporator for a heat pump dryer, the condensation risk assessment of vacuum multi-layer glass and triple glass, optimization of a forced convection type PCM refrigeration module, surface temperature sensor using fluorescent nanoporous thin film. In the area of pool boiling and condensing heat transfer, researches on ammonia inside horizontal smooth small tube, R1234yf on various enhanced surfaces, HFC32/HFC152a on a plain surface, spray cooling up to critical heat flux on a low-fin enhanced surface were actively carried out. In the area of industrial heat exchangers, researches on a fin tube type adsorber, the mass-transfer kinetics of a fin-tube-type adsorption bed, fin-and-tube heat exchangers having sine wave fins and oval tubes, louvered fin heat exchanger were performed. (3) In the field of refrigeration, studies are categorized into three groups namely refrigeration cycle, refrigerant and modeling and control. In the category of refrigeration cycle, studies were focused on the enhancement or optimization of experimental or commercial systems including a R410a VRF(Various Refrigerant Flow) heat pump, a R134a 2-stage screw heat pump and a R134a double-heat source automotive air-conditioner system. In the category of refrigerant, studies were carried out for the application of alternative refrigerants or refrigeration technologies including $CO_2$ water heaters, a R1234yf automotive air-conditioner, a R436b water cooler and a thermoelectric refrigerator. In the category of modeling and control, theoretical and experimental studies were carried out to predict the performance of various thermal and control systems including the long-term energy analysis of a geo-thermal heat pump system coupled to cast-in-place energy piles, the dynamic simulation of a water heater-coupled hybrid heat pump and the numerical simulation of an integral optimum regulating controller for a system heat pump. (4) In building mechanical system research fields, twenty one studies were conducted to achieve effective design of the mechanical systems, and also to maximize the energy efficiency of buildings. The topics of the studies included heating and cooling, HVAC system, ventilation, and renewable energies in the buildings. Proposed designs, performance tests using numerical methods and experiments provide useful information and key data which can improve the energy efficiency of the buildings. (5) The field of architectural environment is mostly focused on indoor environment and building energy. The main researches of indoor environment are related to infiltration, ventilation, leak flow and airtightness performance in residential building. The subjects of building energy are worked on energy saving, operation method and optimum operation of building energy systems. The remained studies are related to the special facility such as cleanroom, internet data center and biosafety laboratory. water supply and drain system, defining standard input variables of BIM (Building Information Modeling) for facility management system, estimating capability and providing operation guidelines of subway station as shelter for refuge and evaluation of pollutant emissions from furniture-like products.