• 제목/요약/키워드: External Heat Input

검색결과 27건 처리시간 0.022초

매개층 산화마그네슘막을 이용한 백금박막 미세발열체의 제작과 마이크로 유량센서에의 응용 (Fabrication of Micro-heaters Using MgO as Medium Layer and It`s Application for Micro-Flowsensors)

  • 홍석우;조정복;정귀상
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 1999년도 추계학술대회 논문집
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    • pp.358-361
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    • 1999
  • This paper describes on the fabrication and characteristics of hot-film type micro-flowsensors integrated with Pt-RTD\`s and micro-heater on the Si substrate, in which MgO thin-films were used as medium layer in order to improve adhesion of Pt thin-films to SiO$_2$ layer The MgO layer improved adhesion of Pt thin-films to SiO$_2$` layer without any chemical reactions to Pt thin-films under high as gas flow rate and its conductivity increased due to increase of heat-loss from sensor to external. Output voltage was 82 mV at N2 flow rate of 2000 sccm/min, heating power of 1.2W. The respons time was about 100 msec when input flow was step-input

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고속응답, 저소비전력형 마이크로 유속센서의 제작과 그 특성 (The fabrication of high-response time, low consumption power, microflowsensor and its characteristics)

  • 홍석우;김병태;김길중;정귀상
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2000년도 추계학술대회 논문집
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    • pp.343-346
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    • 2000
  • This paper presents the characteristics of low consumption, high-response time hot-film type micro-flowsensors with SOI(Si-on-insulator) and trench structures. Output voltages increased due to increase of heat-loss from sensor to external. Compared with no-trench on the SOI structure, the micro-flowsensors with trench structures have properties of high output voltage and low consume power. Output voltage of micro-flowsensors with SOI and trench structures was 250 mV at $N_2$ flow rate of 2000 sccm/min, heating power of 0.3 W. The response time was about 85 msec when input flow was step-input.

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열교환기용 BAS111합금 고주파유도용접관에서 인발조건이 기계적 특성에 미치는 영향 (Effects of Drawing Parameters on Mechanical Properties in High Frequency Induction Welded Tubes of BAS111 Alloy for Heat-exchangers)

  • 국진선;김낙찬;송중근;전동태
    • Journal of Welding and Joining
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    • 제22권4호
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    • pp.65-72
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    • 2004
  • The aim of this study is to investigate the optimum drawing parameter for BAS111 welded tubes. The BAS111 aluminium alloy tubes with 25.4mm in external diameter and 1.5mm in thickness for heat-exchangers were manufactured by high frequency induction welding with the V shaped convergence angle 6.8$^{\circ}$ and power input 50㎾. With increasing the reduction of area (1.6, 5.8, 11.5, 14.2, 18.5, 22.5%) by drawing, tensile strength was increased and elongation was decreased. With increasing the reduction of area by drawing, hardness in weld metal increased rapidly, while that of base metal increased slowly. In the specimen with the outer diameter smaller than 22mm, hardness of weld metal was higher than that of base metal. The optimum drawing parameter of area reduction was estimated about 15% because of the work hardening of welds.

열탄소성 해석에 의한 원주용접 원통관의 잔류응력 예측과 그 영향에 대한 연구 (The Studies on the Prediction of Residual Stresses by Thermal Elasto-Plastic Analysis and its Effect for Circumferential Welded Cylinder)

  • 류기열;엄동석
    • Journal of Welding and Joining
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    • 제15권5호
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    • pp.115-123
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    • 1997
  • The buckling strength, fatigue strength, stress corrosion cracking are considerably effected on one of initial imperfections, the residual stresses produced by a circumferential weld between axisymmetric cylinders. Therefore, we study the residual stresses, plastic strain and temperature distribution with using thermal elasto-plastic analysis which are generated by a circumferential weld between axisymmetric cylinders. It is investigated that welding residual stresses have an effect on the strength of cylinder for inner and outer shell under external pressure.

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고주파유도 용접된 A3003 알루미늄합금 튜브의 기계적 특성에 미치는 열처리조건의 영향 (Effects of Heat-treatment Parameters on Mechanical Properties of A3003 Al Alloy Tubes for Heat-exchangers by High Frequency Induction Welding)

  • 국진선;윤동주;김병일
    • 열처리공학회지
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    • 제19권3호
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    • pp.156-162
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    • 2006
  • The aim of this study is to investigate the full annealing parameter for A3003 Al alloy welded tubes. The A3003 Al alloy tubes with 34 mm in external diameter and 1.3 mm in thickness for OPC drum were manufactured by high frequency induction welding with the V shaped convergence angle $6.7^{\circ}$ and power input 50 kW. The tensile and yield strength decreased with increasing the annealing temperature and time remarkably, but elongation increased remarkably. Vickers hardness in welds and base metal decreased with increasing the annealing temperature and time remarkably. In a certain experimental condition, the welds line in A3003 alloys disappeared at $520^{\circ}C$ for 4hr because of the same mechanical properties and structures between welds and base metal.

고양이 치수에서 열 자극으로 유도된 신경병증 염증에서 치수 혈류량 변화 (Change in Pulpal Blood Flow of Heat-induced Neurogenic Inflammation in Feline Dental Plup)

  • 박민경
    • 한국산학기술학회논문지
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    • 제14권12호
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    • pp.6340-6345
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    • 2013
  • 본 연구는 열 자극으로 유도된 신경성 염증 상태에서 혈류량의 변화와 histamine의 치수혈류 조절에 관해 유기적 관계를 연구함으로써 치수혈류 조절기전을 밝히고자 하였다. 연구방법은 열 마리의 고양이를 전신마취 하에 사용되었으며, 치수혈류의 변화는 레이저 도플러 측정계(Periflux 4001, Stockholm, Sweden)을 사용하여 측정 하였다. 레이저 도플러 측정하는 프로브는 하악 견치의 치면에 위치하였다. 열 자극은 입력/출력 장치와 열 자극 제어 스크립트 파일을 사용하여 치아에 적용하였다. 열($40-65^{\circ}C$)에 따라 치수 혈류량이 증가를 확인하였으며, $55^{\circ}C$에서 가장 큰 변화가 나타났다. 열 자극의 변화가 없는 $45^{\circ}C$에서 Histamine($5{\mu}g/kg/1ml$)를 치아와 가까운 설 동맥으로 주입 시 열 자극만 처치한 그룹보다 현저한 증가가 나타났다. 본 연구는 열적 자극에 의해 발생된 신경성 염증상태에서 치수혈류 변화와 이에 히스타민의 기능적으로 관여함을 나타내주며, 치아 염증 상태의 기전을 밝힐 수 있는 가능성을 보여준다.

지하수정호 결합 복합지열시스템의 시범운영 효과분석 (Analysis of Test Operations Effect of Open-Closed Loops Complex Geothermal System Combined with Groundwater Well)

  • 송재용;김기준;이근춘;정교철
    • 지질공학
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    • 제28권3호
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    • pp.475-488
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    • 2018
  • 본 연구에서는 지하수 관정을 활용하고 밀폐형-개방형이 결합된 복합지열시스템(CWG 시스템)을 시설재배지에 적용하여 열원측 및 부하측의 열교환량과 투입된 전력량 대비 효율을 평가하였다. 또한, 운전 과정에서의 외기온도 및 시설재배지 온도를 평가하여 복합지열시스템 적용시의 냉난방 효과를 분석하였다. 냉방운전시 열원측 열교환량 평가결과, 약 235 L/min의 지하수가 유입되는 개방형에서 평균 90.0 kW/h, 약 85 L/min의 순환수가 유동하는 밀폐형에서 40.1 kW/h의 열교환량이 발생하였으며, 전체 열교환량은평균 130.1 kW/h로 분석되었다. 부하측에서 실질적으로 전달되는 열교환량은 평균 110.4kW/h로 평가되었다. 복합지열시스템의 냉방효율을 분석한 결과, 평균 EER는 5.63으로 분석되었다. 난방운전 시 열원측 열교환량 평가결과, 약 266 L/min의 지하수가 유입되는 개방형에서 평균 60.4 kW/h, 약 86 L/min의 순환수가 유동하는 밀폐형에서 22.4 kW/h의 열교환량이 발생하였으며, 전체 열교환량은 평균 82.9 kW/h로 분석되었다. 부하측에서 실질적으로 전달되는 열교환량은 평균 112.0 kW/h로 평가되었다. 복합지열시스템의 난방효율을 분석한 결과, 평균 COP는 3.92로 분석되었다. 외기온도와 CWG 시스템을 적용한 시설하우스 및 비교 시설하우스 내부온도와의 상관관계를 분석한 결과 30RT 용량의 CWG 시스템 하우스가 비교 하우스에 비해 외기온도 $20^{\circ}C$인 경우 $3.4^{\circ}C$, 외기온도 $25^{\circ}C$인 경우 $6.8^{\circ}C$, 외기온도 $30^{\circ}C$인 경우 $10.1^{\circ}C$, 외기온도 $35^{\circ}C$인 경우 $13.4^{\circ}C$의 온도가 저감되는 것으로 평가되었다. 이러한 결과를 볼 때, 본 시스템을 적용할 경우 일반적으로 외기온도가 $30^{\circ}C$ 이상을 보이는 여름철에 CWG 시스템을 적용하지 않은 시설재배지에 비해 약 $10^{\circ}C$ 이상의 냉방효과가 나타낼 수 있을 것으로 판단된다. 이와 같은 결과는 시설재배지의 복합지열시스템 설계에 활용될 수 있고, 다양한 조건에서의 시험성과와 종합하여 복합지열시스템의 냉난방 효과에 대한 보다 명확한 규명이 가능할 것으로 판단된다.

고주파유도용접된 열교환기용 BAS121합금튜브의 기계적 특성에 미치는 인발조건의 영향 (Effects of Drawing Parameters on Mechanical Properties of BAS121 Alloy Tubes for Heat-exchangers by High Frequency Induction Welding)

  • 한상우;김병일;이현우;전우용;국진선
    • 한국재료학회지
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    • 제14권12호
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    • pp.851-856
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    • 2004
  • The aim of this study is to investigate the optimum drawing parameter for BAS121 welded tubes. The BAS121 aluminium alloy tubes with 25 mm in external diameter and 1.3 mm in thickness for heat-exchangers were manufactured by high frequency induction welding with the V shaped convergence angle $6.5^{\circ}$ and power input 55 kW. With increasing the reduction of area ($13,\;21\%$) by drawing, tensile strength was increased and elongation was decreased. With increasing the reduction of area by drawing, hardness in weld metal increased rapidly, while that of base metal increased slowly. In the specimen with the outer diameter smaller than 22 mm, hardness of weld metal was higher than that of base metal. The optimum drawing parameter of area reduction in BAS121 alloys was estimated about $13\%$ because of the work hardening of welds.

데이터 기반 모델에 의한 온실 내 기온 변화 예측 (Data-Based Model Approach to Predict Internal Air Temperature of Greenhouse)

  • 홍세운;문애경;리송;이인복
    • 한국농공학회논문집
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    • 제57권3호
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    • pp.9-19
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    • 2015
  • Internal air temperature of greenhouse is an important variable that can be influenced by the complex interaction between outside weather and greenhouse inside climate. This paper focuses on a data-based model approach to predict internal air temperature of the greenhouse. External air temperature, solar radiation, wind speed and wind direction were measured next to an experimental greenhouse supported by the Electronics and Telecommunications Research Institute and used as input variables for the model. Internal air temperature was measured at the center of three sections of the greenhouse and used as an output variable. The proposed model consisted of a transfer function including the four input variables and tested the prediction accuracy according to the sampling interval of the input variables, the orders of model polynomials and the time delay variable. As a result, a second-order model was suitable to predict the internal air temperature having the predictable time of 20-30 minutes and average errors of less than ${\pm}1K$. Afterwards mechanistic interpretation was conducted based on the energy balance equation, and it was found that the resulting model was considered physically acceptable and satisfied the physical reality of the heat transfer phenomena in a greenhouse. The proposed data-based model approach is applicable to any input variables and is expected to be useful for predicting complex greenhouse microclimate involving environmental control systems.

GMOH 기법에 의한 공작기계 원점의 열적거동 예측 (Estimation of Thermal Behavior for the Machine Origin of Machine Tools using GMOH Methodology)

  • 안중용
    • 한국공작기계학회:학술대회논문집
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    • 한국공작기계학회 1997년도 추계학술대회 논문집
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    • pp.213-218
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    • 1997
  • Thermal deformation of machine origin of machine tools due to internal and external heat sources has been the most important problem to fabricate products with higher accuracy and performance. In order to solve this problem, GMDH models were constructed to estimate thermal deformation of machine origin for a vertical machining ceneter through measurement of temperature data of specific points on the machine tool. These models are nonlinear equations with high-order polynomials and implemented in a multilayered perceptron type network structure. Input variables and orders are automatically selected by correlation and optimization procedure. Sensors with small influence are deleted automatically in this algorithm. It was shown that the points of temperature measurement can be reduced without sacrificing the estimation accuracy of $\pm$5${\mu}{\textrm}{m}$. From the experimental result, it was confirmed that GMDH methodology was superior to least square models to estimate the thermal behavior of machine tools.

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