• 제목/요약/키워드: heat-transfer simulation

검색결과 952건 처리시간 0.025초

Thermal-hydraulic study of air-cooled passive decay heat removal system for APR+ under extended station blackout

  • Kim, Do Yun;NO, Hee Cheon;Yoon, Ho Joon;Lim, Sang Gyu
    • Nuclear Engineering and Technology
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    • 제51권1호
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    • pp.60-72
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    • 2019
  • The air-cooled passive decay heat removal system (APDHR) was proposed to provide the ultimate heat sink for non-LOCA accidents. The APDHR is a modified one of Passive Auxiliary Feed-water system (PAFS) installed in APR+. The PAFS has a heat exchanger in the Passive Condensate Cooling Tank (PCCT) and can remove decay heat for 8 h. After that, the heat transfer rate through the PAFS drastically decreases because the heat transfer condition changes from water to air. The APDHR with a vertical heat exchanger in PCCT will be able to remove the decay heat by air if it has sufficient natural convection in PCCT. We conducted the thermal-hydraulic simulation by the MARS code to investigate the behavior of the APR + selected as a reference plant for the simulation. The simulation contains two phases based on water depletion: the early phase and the late phase. In the early phase, the volume of water in PCCT was determined to avoid the water depletion in three days after shutdown. In the late phase, when the number of the HXs is greater than 4089 per PCCT, the MARS simulation confirmed the long-term cooling by air is possible under extended Station Blackout (SBO).

아크 점용접 구조물의 정밀 용접 열변형 해석에 관한 연구 (I) -온도 모니터링 및 열전달 모델 정립- (The Analysis of Welding Deformation in Arc-spot Welded Structure (I) - Temperature Monitoring and Heat Transfer Analysis -)

  • 이원근;장경복;강성수;조상명
    • Journal of Welding and Joining
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    • 제20권4호
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    • pp.544-550
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    • 2002
  • Arc-spot welding is generally used in joining of precise parts such as case and core in electronic compressor. It is important to control joining deformation in electronic compressor because clearance control in micrometer order is needed for excellent airtightness and anti-nose. The countermeasures far this deformation in field have mainly been dependent on the rule of try and error by operator's experience because of productivities. For control this deformation problem without influence on productivities, development of exact simulation model should be needed. In this study, to solve this deformation problem in arc-spot welded structure with case and core, we intend to make a simulation model that is able to predict deformation in precise order by tuning and feedback between sensing data and simulation results. This paper include development of heat input model for arc-spot welding, temperature monitoring and make a heat transfer model using sensing data in product.

밀집형 열교환기 내 공기 측 대류열전달특성 (Analysis for Air-Side Convective Heat Transfer Characteristics in Compact Heat Exchangers)

  • 모정하;이상호
    • 대한설비공학회:학술대회논문집
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    • 대한설비공학회 2009년도 하계학술발표대회 논문집
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    • pp.1443-1448
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    • 2009
  • Numerical analysis has been carried out to investigate air-side convective heat transfer characteristics in compact heat exchangers with continuous plate fins. Simulation results such as air flow and temperature distributions are presented, and heat transfer characteristics are compared for various inlet conditions. Results from various turbulence models are also compared for applicability. There is large difference between the local heat transfer coefficient distributions along the cylinder wall for circular tubes. Colburn j factors from the calculated results of circular and flat tubes in the heat exchangers are compared for various Reynolds number. The predicted results in this study can be applied to the optimal design of air conditioning system. with compact heat exchanger.

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백신 수송용 포장재 내부에서 열 전달의 모델링 및 시뮬레이션 (Modeling and Simulation of Heat Transfer inside the Packaging Box for Vaccine Shipping)

  • 다오 반 둥;최호석;이성찬;배윤성
    • Korean Chemical Engineering Research
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    • 제46권3호
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    • pp.604-609
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    • 2008
  • 본 연구에서는 세계보건기구의 기준을 만족시키기 위한 포장재 개발을 목적으로 백신 수송용 장방형 포장재 내부열 전달에 대한 모델링 및 시뮬레이션을 수행하고 이를 실험결과와 비교하였다. 장방형의 박스를 구형 박스로 전환하여 구상한 1차원 모델은 냉각공정의 경우에는 실험 결과와 비교적 잘 일치하는 결과를 보였으나, 가열공정에서는 실험결과와 상당한 차이를 보여주었다. 이는 가열공정을 계산할 때, 포장재 외부에서의 경계조건을 적절히 고려해주지 못한 결과로 사료된다. 그러나, 본 연구를 통하여 상전이 물질을 함유한 다층 벽을 통한 열 전달의 문제를 전산 모사할 수 있는 기본적인 알고리즘을 성공적으로 개발할 수 있었다.

A2024 와 SM45C 마찰용접의 열전달 해석 (Heat Transfer Analysis of Friction Welding of A2024 to SM45C)

  • 이상윤;윤병수
    • 한국공작기계학회논문집
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    • 제10권1호
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    • pp.65-70
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    • 2001
  • The hear transfer mechanism initiating the friction welding is examined and a transient three dimensional heat conduc-tion model for the welding of two dissimilar cylindrical metal bars is investigated. The cylindrical metal bars are made of materials made of A2024 and SM 45C. Numerical simulations of heat flow are performed using the finite volume method. Respectively. Commercial FLUENT code is used in the heat flow simulation and maximum temperature and distribution of temperature are calculated. Temperature of friction welded joining face is compared with the temperature distribution measured by experiment and numerical simulation. The maximum temperature of friction welded joining face is lower than melting point of A2024-T6 aluminum alloy using insert metal. The temperature distribution of friction welded join- ing face with insert metal is more uniform than that of without inset metal.

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$45^0$의 rib이 설치된 채널에서의 열전달과 유동특성의 실험 및 수치해석 (Experimental & Numerical Investigation for Heat Transfer and Flows in a $45^0$ Inclined Ribbed Square Channel)

  • 강호근;안수환;김명호
    • 한국마린엔지니어링학회:학술대회논문집
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    • 한국마린엔지니어링학회 2005년도 후기학술대회논문집
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    • pp.178-179
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    • 2005
  • Numerical and experimental investigation of incompressible turbulent flow and heat transfer through square channels with varying number of ribbed walls were conducted to determined pressure drop and heat transfer. The CFX solver used for the computation. The rough walls have a $45^0$ inclined square rib. Uniform heat flux is maintained on whole inner heat transfer channel area. The numerical results agreed well with experimental data that obtained for 7600$D_h$) of 0.0667. The results show that values of local heat transfer coefficient and friction factor increase with an increasing number of ribbed walls.

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열전달 해석을 이용한 VAR 공정 변수가 티타늄 합금 잉고트 응고 조직에 미치는 영향 연구 (The Effects of VAR Processing Parameters on solidification Microstructures in Ti Alloys by Computer Simulation)

  • 김종환;이재현;허성강;현용택;이용태
    • 한국재료학회지
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    • 제12권5호
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    • pp.398-406
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    • 2002
  • VAR process is required to control its various operating parameters. Heat transfer simulation has been accomplished to understand development of solidification micro and macro-structures during VAR process in Ti alloys. Optimum VAR process parameters could be also estimated in this study. It was found that macro-structures were closely related to the shape and depth of liquid pool, and solidification parameters, such as temperature gradient, heat flux, solid fraction. The cooling rates were higher at bottom, top, and center part respectively. As cooling rates increased, the $\alpha$ phase decreased in length, width and fraction. In order to evaluate which parameter affects the result of heat transfer calculation most sensitively, the sensitivities of input parameters to the simulation result were examined. The pool depth and cooling rate showed more sensitive to the temperature of the molten metal, heat transfer coefficient, and liquidus respectively. Also, these thermal properties became more sensitive at higher temperatures.

고효율/친환경 전기 용해로 내의 열전달 해석 (Heat Transfer Analysis in High Efficiency Electric Melting Furnace)

  • 설동일;이병화;전충환;장영준
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2007년도 춘계학술대회B
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    • pp.2285-2290
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    • 2007
  • The main objective of this study is to analyze the heat transfer characteristics in the electric melting furnace. Local temperatures are measured at various location in the furnace using the B-type thermocouples. In this paper, the numerical simulation was performed using the ANSYS software, and compared with experimental data. Mathematical heat transfer model for the prediction of temperature distribution has been developed by considering the thermal radiation among heating element, crucible and insulating materials. The results show that the temperature distributions predicted by the numerical simulation agree with experimental results comparatively.

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사각 또는 반원 형상의 요철이 설치된 채널 내부의 유동 및 열전달의 큰에디모사 (Large Eddy Simulation of Flow and Heat Transfer in a Channel Roughened by Square or Semicircle Ribs)

  • 안준;최해천;이준식
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2004년도 춘계학술대회
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    • pp.1436-1441
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    • 2004
  • The internal cooling passage of a gas turbine blade can be modeled as a ribbed channel. Most studies have considered square ribs. However, the ribs can be rounded due to improper manufacturing or wear during the operation. Hence, we have studied two different rib geometries in this study, i.e. square and semicircle ribs. We have performed large eddy simulations (LES) and experiments to validate the results from the simulations. LES predicts the detailed flow and thermal features, which have not been captured by simulations using turbulence models. By investigating the instantaneous flow and thermal fields, we propose the mechanisms for the local heat transfer distribution between ribs. For both the geometries, heat transfer is enhanced by the entrainment of the cold fluid by the vortical motions and impingement of the entrained cold fluid on the ribs.

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다중버너 수관식 보일러를 위한 전열모듈의 열전달 특성: 0.5 t/h급 모형 수치해석 (Heat Transfer Module for Multi-Burner Water Tube Boiler: 0.5 t/h Class Model Simulation)

  • 안준;김종진;강새별
    • 대한설비공학회:학술대회논문집
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    • 대한설비공학회 2007년도 동계학술발표대회 논문집
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    • pp.528-533
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    • 2007
  • A finned tube type heat transfer module has been proposed for a multi-burner water tube boiler. Fins change their geometry along the streamwise direction to maximize the performance, which makes it difficult to apply conventional bulk analysis. The design program has been improved by updating data for every row of tubes along the flow. A numerical simulation has been also performed to evaluate the effect of inlet conditions and validated with experiment. The heat transfer of the first row has been underpredicted by the conventional Zhukauskas correlation, where the acceleration of the flow due to the blockage is not fully inflected. The fin tip temperature is also underpredicted by Bessel solution, because of the interaction with neighboring fins.

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