• 제목/요약/키워드: Pinch Analysis

검색결과 71건 처리시간 0.044초

Optimal synthesis and design of heat transfer enhancement on heat exchanger networks and its application

  • Huang, Zhao-qing
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 1996년도 Proceedings of the Korea Automatic Control Conference, 11th (KACC); Pohang, Korea; 24-26 Oct. 1996
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    • pp.376-379
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    • 1996
  • Synthesis for qualitative analysis in connection with quantitative analysis from the pinch design method, EVOP and Operations Research is proposed for the optimal synthesis of heat exchanger networks, that is through of the transportation model of the linear programming for synthesizing chemical processing systems, to determine the location of pinch points, the stream matches and the corresponding heat flowrate exchanged at each match. In the second place, according to the optimization, the optimal design of heat transfer enhancement is carried on a fixed optimum heat exchanger network structure, in which this design determines optimal operational parameters and the chosen type of heat exchangers as well. Finally, the method of this paper is applied to the study of the optimal synthetic design of heat exchanger network of constant-decompress distillation plants.

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이행형 토치에서의 아크 플라즈마의 물리적 거동에 관한 연구 (A study on the physical behavior of arc plasmas in transferred-type Torch)

  • 김외동;고광철;강형부
    • 대한전기학회논문지
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    • 제45권3호
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    • pp.415-425
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    • 1996
  • This study presents an analytical method of solving the behaviors of arc plasma in a nozzle constricting transferred-type torch and purposes to obtain the basic data for the design of a plasma torch, which can be obtained from the temperature, pressure, velocities and voltage distributions. We have to solve some conservation equations simultaneously and need to know the exact thermal gas properties in order to obtain the correct behaviors of arc plasma. It is also necessary to give the relevant physical or geometric boundary conditions. For the simplicity of analysis, we assumed that (a) the plasma flow is laminar, (b)the local thermodynamic equilibrium, i.e. LTE, prevails over the entire arc column region. The electrode sheath effects were neglected and the nozzle area was excluded from the analysis by assuming that the current flow into the nozzle is zero. We solved the momentum transfer equation including the self-magnetic pinch effect, and obtained the temperature distribution from the energy conservation equation. From this temperature, we could get arc voltage distribution. (author). refs., figs., tabs.

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고유수용성신경근 촉진법 훈련과 동작관찰 훈련이 뇌졸중 환자의 상지 운동기능에 미치는 효과: 단일사례 연구 (Effect of Proprioceptive Neuromuscular Facilitation and Action Observation Training on Upper Extremity Motor Function in Stroke Patient: A Single-Subject Study)

  • 박혜령;이문규;윤태원
    • 한국전문물리치료학회지
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    • 제22권1호
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    • pp.69-78
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    • 2015
  • This study evaluated and compared the effectiveness on upper motor extremity function between proprioceptive neuromuscular facilitation which has been frequently used in clinical practice, and action observation training in terms of improving upper motor extremity function. A study with a single-subject design (A-B-C-A') was conducted with a patient who was diagnosed with left hemiplegia. A repeated-measure analysis was conducted to assess results of the Wolf Motor Function Test (WMFT), Box and Block Test (BBT), and grip and pinch strength test performed daily in the study for 4 weeks. The results of the analysis indicated that the WMFT score, BBT score, grip strength, and pinch strength were improved from 29.60 to 39 (24.10%), from 1.67 to 4.93 each (EA) (66.22%), from 2.06 to 2.66 libras (lbs) (22.61%), and from 1.57 to 1.93 lbs (18.94%), respectively, from the baseline period to treatment period B. The values were improved from 29.60 to 42.20 (29.86%), from 1.67 to 7 EA (76.21%), from 2.06 to 3.47 lbs (40.57%), and from 1.57 to 1.67 lbs (6.12%), respectively, from the baseline period to treatment period C. From treatment period B to treatment period C, the WMFT score, BBT score, and grip strength were improved from 39 to 42.20 (7.58%), from 4.93 to 7 EA (29.56%), and from 2.66 to 3.47 lbs (23.20%), respectively, but pinch strength was decreased from 1.93 to 1.67 lbs (15.83%). In conclusion, proprioceptive neuromuscular facilitation and action observation training both have positive effects on upper extremity motor function. However, we suggest that the posttreatment effect of action observation training was better than that of proprioceptive neuromuscular facilitation.

공정용수 재이용 최적화를 통한 용수 및 폐수 최소화 기술 (Water and Wastewater Minimization Technology Through Process Water-Reusing Optimization)

  • 유창규;이태영;이인범
    • 대한환경공학회지
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    • 제28권9호
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    • pp.961-976
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    • 2006
  • 최근에 배출수를 고도 처리하여 재이용하는 기존의 방법에서 벗어나 공정 내에서 용수를 절약함과 동시에 생산 공정의 과학적이고 체계적인 분석을 통하여 용수의 이용률을 극대화한 후 최종 방류함으로써 물이용의 효율성을 높이고자 하는 용수재이용 기술이 많은 관심을 받고 있다. 이에 따라 제지, 석유화학 및 철강 산업 같이 용수를 많이 필요로 하는 용수 과소비 산업의 경우 공정수의 내부 재순환을 최적화 하여 유입되는 공업용수를 저감하는 동시에 재이용수의 사용으로 전체 용수 사용량을 줄이고 폐수의 방류량을 줄이고자 하는 워터핀치기술(water pinch technology)에 대한 관심이 높아지고 있다. 이 기법은 공정수의 재이용을 최적화 시켜 주는 방법을 사용하기 때문에 폐수의 방류량을 줄이면서 전 생산 공정을 대상으로 최적의 공정용수 재이용 라인을 구축할 수 있는 것으로 알려져 있다. 본 총설에서는 공정 설계 단계에서 병목을 찾아 재이용 최적화를 통해 용수 및 폐수 최소화하는 워터핀치 기술과 국내외 산업체에서 용수 재이용 네트워크 설계의 사례연구를 소개하고자 한다. 또한 최근 각광을 받는 에너지와 용수 재이용 네트워크의 동시 설계와 생태산업단지에서 기업간 용수 재이용 네트워크 설계 같은 최신 연구 동향을 소개한다.

역대향류 열교환기의 열 핀치(thermal pinch)에 관한 연구 (A Study on the thermal pinch problem in the counterflow heat exchanger)

  • 최성은;진영욱
    • 대한안전경영과학회:학술대회논문집
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    • 대한안전경영과학회 2008년도 추계학술대회
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    • pp.659-667
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    • 2008
  • The LNG carriers have been propelled by steam turbines and the LNG boil-off(BOG) has been used as fuel or vented. However, as the alternative propulsion systems such as diesel engines are being equipped on the LNG carriers for better fuel efficiency, a need for the LNG BOG re-liquefaction system that liquefies the BOG and sends the liquid BOG back to the LNG cargo has arisen in recent years. This study investigates the design of the BOG re-liquefaction system based on the reverse Brayton refrigeration cycle. The thermodynamic and heat exchanger analysis are carried out and the limitations to the system performance are discussed.

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