• 제목/요약/키워드: Heat Transfer Control

검색결과 549건 처리시간 0.022초

복사열전달을 고려한 고층아파트 연속난방 열공급제어 시뮬레이션 (Simulation of Heat Supply Control of Continuous Heating System of Multistoried Apartment in Consideration of Radiation Heat Transfer)

  • 최영돈;홍진관;윤종호;이남호
    • 설비공학논문집
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    • 제6권2호
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    • pp.78-92
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    • 1994
  • Thermal performance of pipe network of continuous heating system controlled by thermostat and flow control valve was simulated in consideration of radiation heat transfer and solved by linear analysis method. Thermal performance of real apartment building with radiant floor heating system was simulated by equivalence heat resistance-capacity method. This method enables to simulate the unsteady variation of temperature or each element of building. Heat transfer characteristics of each element were also investigated.

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분리벽형 증류탑의 최적 설계를 위한 내부 순환량 분포와 전열 특성 연구 (Internal Recycle Distribution and Heat Transfer Effect for Optimal Design of Dividing Wall Distillation Columns)

  • 정성오;이기홍;이문용
    • 제어로봇시스템학회논문지
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    • 제9권3호
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    • pp.236-241
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    • 2003
  • This paper addresses the optimal design of dividing wall distillation column which is rapidly applied in a variety of chemical processes over recent several years because of its high energy saving efficiency. A general dividing wall column model which can cope with the heat transfer through the dividing wall is developed using rigorous computer simulation. Based on the simulation model, the effects of the internal recycle flow distribution around the dividing wall and the heat transfer across the dividing wall on overall system performance are investigated. An improved column design method is suggested to utilize the heat transfer through the wall. The suggested method is compared with the existing method via simulation study in which the proposed design shows improved energy saving result.

일방향 연계를 활용한 연속가변 추력제어 시스템의 열전달 해석 (Heat Transfer Analysis for Variable Thrust Control System Using 1-Way Coupling)

  • 이지훈;장한나;김규빈;조진연;곽재수;고준복;박성한
    • 한국추진공학회:학술대회논문집
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    • 한국추진공학회 2017년도 제48회 춘계학술대회논문집
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    • pp.388-391
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    • 2017
  • 본 연구에서는 상용 전산 유체 해석 코드와 상용 유한 요소 해석 코드를 연계하여 연속가변 추력제어 시스템의 열전달 해석을 수행하였다. 유동해석을 수행하여 온도 및 대류 열전달 계수를 도출하였고, 이 결과 값을 Mapping 방식을 이용하여 열전달 해석의 경계 조건으로 부가하였다. 열전달 해석을 수행하여 왕복 운동하는 추력조절기의 기밀을 위하여 장착되는 O-ring에 전달되는 온도를 예측하였다.

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열전달 특성을 고려한 공기압 압력제어계의 감압제어특성 해석 (Analysis of Decompression Control Characteristics of Pneumatic Pressure Control System Considering Heat Transfer Characteristics)

  • 장지성
    • 동력기계공학회지
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    • 제10권1호
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    • pp.90-95
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    • 2006
  • Pneumatic control systems have been mainly used as a high speed operating system. Therefore, state change of air in a control volume was assumed to be adiabatic change and, pneumatic control systems have been analyzed by using this assumption. Especially, when absolute value of pressure change in the control volume is small, there is a tendency to neglect effect of temperature change on pneumatic control system because temperature change owing to pressure change is small. In this study, an effect of temperature change of air on the decompression control process was analyzed by considering change of mass flow rate, and heat transfer characteristics between air in the chamber and the chamber wall. As a result, this study could confirm that a slight temperature change of the air in the pneumatic pressure control system can influence on the dynamic characteristics of pressure response, and pressure control performance.

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충돌제트 열전달에 발포알루미늄 방열기의 높이와 노즐의 크기가 미치는 영향 (Effects of Nozzle Size and Height of Aluminum Foam Heat Sink on Jet Impingement Heat Transfer)

  • 김서영;백진욱;강병하
    • 대한기계학회논문집B
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    • 제25권9호
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    • pp.1263-1271
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    • 2001
  • An experimental study is carried out for an aluminum foam heat sink attached to an isolated heat source to evaluate high potential of aluminum foam as a heat sink with impinging jets. The effects of the pore density and the height of the aluminum foam heat sink, the jet Reynolds number, and the nozzle diameter are delineated in comparison with a conventional pin type heat sink. It is found that the aluminum foam with small pores is inefficient for the heat transfer enhancement due to the large flow friction at the given porosity. In the parameter ranges of the present study, the change in the nozzle diameter shows no significant effects on the surface temperature of the aluminum foam heat sink at a given Reynolds number. The heat transfer enhancement is strongly dependent on the jet Reynolds number and shows a maximum value at a moderate Reynolds number.

과도 액정 기법을 이용한 열전달 계수 측정법에 관한 실험적 연구 (Experimental Study on the Measurement Method of Heat Transfer Coefficients Using a Transient Liquid Crystal Technique)

  • 홍철현;정준화;양장식;이기백
    • Journal of Advanced Marine Engineering and Technology
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    • 제27권5호
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    • pp.581-588
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    • 2003
  • Heat transfer characteristics of a pair of longitudinal vortices using a transient liquid crystal technique are studied experimentally. In order to control the strength of longitudinal vortices, angle of attack of the vortex generators is $20^{\circ}$and the length of space from the centerline the vortex generations is 25mm apart. The heat transfer measurements using a transfer coefficients. The following conclusions are obtained from the present experiment. When any vortex generators are not set up in wind tunnel test, heat transfer rate is low respectively. However, with the vortex generators of rectangular winglet, the heat transfer on the local surface can be enhanced.

판형 열교환기의 열전달성능 손실 없이 유동방향 길이를 축소하는 방법 (A Method to Reduce Flow Depth of a Plate Heat Exchanger without a Loss of Heat Transfer Performance)

  • 송귀은;이대영
    • 설비공학논문집
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    • 제18권2호
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    • pp.129-136
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    • 2006
  • Optimal design of an air-to-liquid finned plate heat exchanger is considered theoretically in this study. Based on existing correlations for the pressure loss and the heat transfer in channel flows, the optimal configuration of the plate heat exchanger including the optimal plate pitch and the optimal fin pitch is obtained to maximize the heat transfer within the limit of the pressure drop for a given flow depth of the plate heat exchanger. It is found that the optimal fin pitch is about one ninth of the optimal plate pitch. In the optimal configuration, the flow and thermal condition in the channels is just at the boundary between the laminar developing and laminar fully developed states. It is also found when reducing the flow depth of plate heat exchangers for compactness, the heat transfer performance can be maintained exactly the same if the geometric parameters such as the plate thickness, plate pitch, fin thickness, and fin pitch are reduced proportional to the square root of the flow depth as long as the flow keeps laminar within the heat exchangers.

원형제트출구 전단류 조절에 따른 제트충돌면에서의 열전달 특성 ( 2 ) - 음향여기된 제트 - (Heat Transfer Characteristics on Impingement Surface with Control of Axisymmetric Jet ( 2 ) - With Acoustic Excitation -)

  • 황상동;이창호;조형희
    • 대한기계학회논문집B
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    • 제24권3호
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    • pp.373-381
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    • 2000
  • The flow and heat transfer characteristics on the impingement surface can be controlled by the change of vortex with the acoustic excitation, because the flow characteristics of an impinging jet are affected strongly by the vortices formed at the jet exit. To investigate the effects of acoustic excitation, we measured the velocity, turbulent intensity distributions for the free jet and local heat transfer coefficients on a impingement surface. As the acoustic excitation, subharmonic frequency of excited frequency plays an important role to the control of the jet flow. If the vortex pairings are promoted by the acoustic excitation, turbulence intensity of the jet flow is increased quickly. On the other hand if the vortex pairings are suppressed, the jet flow has low turbulence intensity at the center of the jet. Therefore, the low heat transfer rates are obtained on the impingement plate for a small nozzle-to-plate distance. However, it has high heat transfer rates at a large distance between the nozzle and plate due to the increasing of potential-core length.

자동차용 증발기 판 내의 증발 열전달 및 유동 특성에 관한 실험적 연구 (An Experimental Study on In-Plate Evaporation Heat Transfer and Flow Characteristics for Automobile)

  • 곽경민;주상우;정우열;김택근;김광일
    • 한국자동차공학회논문집
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    • 제15권2호
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    • pp.95-100
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    • 2007
  • An experimental study was performed to evaluate the in-plate evaporation heat transfer and flow characteristics of a evaporator used in automobile. Two test-cores with different heat transfer area, bead-shape and bead-array were tested, A type and B type. For the heat transfer, Nusselt number for B type test-core reaches a value nearly equal to the one for A type test-core, in the whole range of equivalent Reynolds number. But, for the same mass flow rate of refrigerant, hA for B type test-core becomes higher with the increase of the mass quality of refrigerant than for A type test-core. In a flow visualization experiment, the wake zone of refrigerant circulating at u-turn position of plate is observed.

가공관의 외벽에서 친수성 표면처리가 증발열전달에 미치는 영향 (Effects of Hydrophilic Surface Treatment on Evaporation Heat Transfer at the Outside Wall of Enhanced Tubes)

  • 박노성;황규대;김호영;강병하;정진택
    • 대한기계학회논문집B
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    • 제25권5호
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    • pp.666-672
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    • 2001
  • Experiments have been carried out to investigate the evaporation heat transfer characteristics of various tubes on which hydrophilic surface treatment using plasma was employed. Spiral, corrugated and low-finned tubes were selected as test tubes. The evaporator tubes were bundled to form three rows of tubes connected in series, with each row being 400mm long. The results obtained indicate that hydrophilic treated tubes tested exhibit better evaporation heat transfer performance as compared with untreated tubes. It is found that the high wettability of the surface obtained through hydrophilic treatment induces film flow onto the tubes during the evaporation process, while sessile drops are formed on untreated tubes.