• 한국압력기기공학회 논문집
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• 제18권2호
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• pp.69-76
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• 2022

In order to prepare for a future nuclear market, research for developing floating small modular reactor has been initiated with the aim of differentiating it from large nuclear power plants such as distributed power, heat supply to remote communities and sea water desalination. Depending on the characteristics of the small modular reactor, it is necessary to design a plate and shell heat exchanger that can be manufactured smaller than the U-tube recirculation method. In this study, 12 cases are selected by changing the diameter of the heat plate, the thickness of the device body and the size of the stiffener. Finite element analysis is performed by setting the stress classification lines for the point at which deformation is expected under external pressure conditions for these analysis cases. For the basic design of the plate and shell heat exchanger, the optimal conditions are derived by analyzing the tendency of stress change in the device body and stiffener.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.2085-2090
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• 2007

This paper describes the possible way to improve the capacity, the efficiency and the pressure drop of $CO_2$ system. It is considered the use of an internal heat exchanger (IHX) to improve the performance of the $CO_2$ system. Experiment was performed by changing a tube shape, a tube number and a tube length of IHX to investigate the performance of IHX for $CO_2$ system. The focus of the present study is to obtain the concept on IHX optimal design. Experimental results show that design parameters are closely related with the capacity and the pressure drop of $CO_2$ system. In the transcritical $CO_2$ cycle, the system performance is very sensitive to the IHX design. System performance on operation condition and shape of IHX is also introduced.

• 한국전산유체공학회지
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• 제16권2호
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• pp.56-61
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• 2011

Numerical study is conducted to design the high temperature heat exchanger of Stirling engine by using the commercial CFD solver, FLUENT. The Fin-tube type of heat exchanger is designed as a reference model by considering the type of engine which is ${\beta}$-configuration. To find the optimal design of heat exchanger in heat transfer capacity numerical calculation is conducted by changing the shape, the number, and material of reference model in three-dimensional combustion field. Adjusted one-way constant velocity of working fluid that is helium is considered as the representative velocity of oscillating flow. The optimal design of heat exchanger considering the heat transfer capability is suggested by using the calculation results.

• 한국에너지공학회:학술대회논문집
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• 한국에너지공학회 1996년도 추계학술발표회 논문집
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• pp.77-80
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• 1996

우리나라에서 피크부하용으로 사용하는 복합발전이 하계시에서 외기온도가 상승함에 따라 실제로는 정격출력을 내지 못하고 있다. 따라서 본 연구에서는 연료(LNG)의 냉열을 이용하여 가스터빈의 연소용공기를 냉각시킬 경우, 복합발전 시스템의 성능변화를 분석하기 위하여 시뮬레이션을 수행하였다. 그 결과 LNG의 냉열을 이용하여 연소용공기를 원하는 온도까지 냉각시킬 수 있음을 확인할 수 있었다. 또한 연소기로 연료를 투입하기전에 설계온도까지 예열시키는 열교환기를 통해 배기가스에 함유된 현열을 더욱 많이 회수하면서, 가스터빈 투입연료의 온도를 상승시킬 수 있어, 시스템효율이 더욱 상승함을 알 수 있었다. 결론적으로 외기온도가 변하는 경우에, 본 시스템의 도입을 위해서는 경제성분석과 더불어 열교환기 시스템의 최적합성이 추후 진행되어야 할 것이며, 이를 통해 최적의 발전시스템을 구성할 수 있으리라 생각된다.

• 한국전산유체공학회지
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• 제12권3호
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• pp.13-19
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• 2007

A numerical simulation on the heat transfer and flow field was carried out to improve the performance of the shell and tube heat exchanger. The steady incompressible 3-D Navier-Stokes solution is obtained with the actual operational condition and geometry of the heat exchanger. Based on this study, it is noted that the present geometry of the heat exchanger causes poor heat transfer since the air inside shell does not flow through the tube bundle, but around it. The enhancement of the heat transfer can be achieved by the variation of the design factor like the sealing strip located on the top/bottom and middle of the baffle, but it causes the increasement of the pressure drop. In this paper, the effects of the location and size of the sealing strips and flow rate through the heat exchanger on the heat transfer and pressure drop are studied.

• 한국압력기기공학회 논문집
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• 제12권1호
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• pp.85-92
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• 2016

The operating temperature of VHTR components is much higher than that of conventional PWR due to high core outlet temperature of VHTR. Material requirements and technical issues of VHTR reactor components which are mainly dominated by high temperature service condition were discussed. The codification effort for high temperature material and design methodology are explained. The design class for VHTR components are classified as class A or B according to the recent ASME high temperature reactor design code. A separation of thermal boundary and pressure boundary is used for VHTR components as an elevated design solution. Key design characteristics for reactor pressure vessel, control rod, reactor internals, graphite reflector, circulator and intermediate heat exchanger were analysed. Thermo-mechanical analysis of the process heat exchanger, which was manufactured for test, is presented as an analysis example.

• 설비공학논문집
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• 제13권7호
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• pp.612-620
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• 2001

The optimum design of a heat exchanger with porous media insertion is studied in this paper. It is considered that the aluminum foam metal is inserted in a flat plate channel and air flows through it. The influence of the microstructure of the foam metal on the pressure drop and heat transfer is investigated utilizing previous analytical results and existing correlation equations. Design parameters are identified as the unit-cell size and the ligament thickness of the porous medium, and their effects are examined. The results show that there exists optimum microstructure of the porous media maximizing heat transfer with a constant pressure drop. When the increase in the pressure drop is within a practically acceptable range, the increase in the heat transfer is dominated by the increase in the heat transfer area due to the porous medium insertion. Consequently, among the porous media with a constant pressure drop, the heat transfer is maximized with a microstructure with maximum specific surface area.

• 유공압시스템학회논문집
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• 제5권2호
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• pp.8-13
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• 2008

Shell-and-tube type heat exchangers are generally classified with fixed tube-sheet and floating tube-sheet heat exchangers. In this paper, we employed the fixed tube-sheet heat exchangers. We theoretically investigated the safety evaluation of our shell-tube heat exchanger by axial, bending and equivalent stress of fin tubes, tube plates, channels and shell. Design pressure ranges were chosen pressure($0.6{\sim}2\;MPa$) on tube side and 200 %(3 MPa) of Maximum pressure on shell side for safety evaluation of heat exchangers. This research will be useful for fabrication of heat exchangers to prevent against damage hazard of heat exchangers in operation.

• 한국유체기계학회 논문집
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• 제14권5호
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• pp.55-62
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• 2011

Shape optimization of a Printed circuit heat exchanger (PCHE) has been performed by using three-dimensional Reynolds-Averaged Navier-Stokes (3-D RANS) analysis and surrogate modeling techniques. The objective function is defined as a linear combination of effectiveness of the PCHE term and pressure drop in the cold channels of the PCHE. The cold channel angle and the ellipse aspect ratio of the cold channel are used as design variables for the optimization. Design points are selected through Latin-hypercube sampling. The optimal point is determined through surrogate-based optimization method which uses 3-D RANS analyses at design points. The results of three types of surrogate model are compared each other. The results of the optimizations indicate improved performance in friction loss but low performance in effectiveness than the reference shape.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2010년 춘계학술대회논문집
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• pp.163-166
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• 2010

Numerical analysis is conducted to design the high temperature heat exchanger of Stirling engine by using the commercial CFD solver FLUENT. The fin-tube type of heat exchanger numerical calculation is conducted by changing the shape, number and material of fin shape of working fluid channel, etc in three-dimensional combustion field. Adjusted one-way constant velocity is used as the representative velocity of oscillating flow. The optimum design of heat exchanger considering the heat trasfer capability is suggested by using the calculation results.