• Journal of Advanced Marine Engineering and Technology
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• 제38권4호
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• pp.367-375
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• 2014

셀-튜브 열교환기는 산업분야에서 가장 널리 사용되는 열교환기이다. 열교환기의 열적 성능을 개선하기 위하여 셀-튜브 열교환기에 대해 배플의 배치, 배플의 방향, 배플의 표면의 돌기형상 등의 인자를 변경하였으며, 유동의 박리 및 경계층해석에 적절히 이용되는 SST 난류모델을 적용하여 열전달특성을 고찰하였다. CFD해석시 경계조건는 셀측의 입구온도를 344K로 일정하게 하고, 물의 유량을 6, 12, 18, 24 l/min로 변화시켰다. 그 결과로는 지그재그형 배치가 열전달률 및 압력강하가 향상되는 것으로 나타났으며, 배플의 방향은 기존형보다 수직형 및 각도 $45^{\circ}$형이 열전달이 향상되는 것으로 나타났고, 압력강하는 거의 차이가 없었다. 또한 배플의 돌기형상은 열전달면적을 증가시킴으로써 열전달률 및 압력강하가 향상됨을 알 수 있었다. 해석결과를 통하여 열전달 증가가 유동의 박리, 유체의 체류시간, 튜브와의 접촉면적, 유량, 와류 등에 따라 크게 영향을 받는다는 것을 알 수 있었다.

• 대한기계학회논문집B
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• 제24권1호
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• pp.50-59
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• 2000

An experimental study has been carried out in order to investigate the heat storage characteristics for a latent heat storage tank with horizontal shell and tube type. The heat exchanger consisted of horizontal cylindrical capsules with a staggered tube bank layout. Based on the obtained data, the effects of flow rate and inlet fluid temperature on the melting time and heat storage rates were examined. It is found that the melting time decreased with increase of the flow rate and the inlet temperature. Results also show that at the initial stage of heat transfer the heat storage rate represents the maximum value and rapidly decreases.

• 제어로봇시스템학회논문지
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• 제20권5호
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• pp.543-550
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• 2014

In many industrial processes and operations, such as power plants, petrochemical industries and ships, shell and tube heat exchangers are widely used and probably applicable for a wide range of operating temperatures. The main purpose of a heat exchanger is to transfer heat between two or more medium with temperature differences. Heat exchangers are highly nonlinear, time-varying and show time lag behavior during operation. The temperature control of such processes has been challenging for control engineers and a variety of forms of PID controllers have been proposed to guarantee better performance. In this paper, a scheme to control the outlet temperature of a shell and tube heat exchanger system that combines the PID controller with feedforward control and anti-windup techniques is presented. A genetic algorithm is used to tune the parameters of the PID controller with anti-windup and the feedforward controller by minimizing the IAE (Integral of Absolute Error). Simulation works are performed to study the performance of the proposed method when applied to the process.

• 설비공학논문집
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• 제13권5호
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• pp.363-363
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• 2001

• 한국해양공학회지
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• 제18권1호
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• pp.69-74
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• 2004

In general, the protection method of Shell and Tube Type heat exchanger for a vessel has been applied as a sacrificial anode, which is attached at the inner side of the shell. However, this is an insufficient protection method for tube. Therefore, a more suitable method, such as the impressed current cathodic protection for tube protection, is required. Al-brass is the raw material of tubes for heat exchanger of a vessel where seawater is used for cooling the water. It has a high level of heat conductivity, excellent mechanical properties, and a high level of corrosion resistance, due to a cuprous oxide (Cu$_2$O) layer against th seawater. However, in actuality, it has been reported that Al-brass tubes for heat exchanger of a vessel can produce local corrosion, such as stress corrosion cracking (SCC). This paper studied the effect of impressed potential on the stress corrosion cracking of Al-brass for impressed current cathodic protection in 3.5% NaCl +0.1% NH$_4$OH solution, under flow by a constant displacement tester. Based on the test results, the latent time of SCC, stress corrosion crack propagation, and the dezincification phase of Al-brass are investigated.

• Journal of Advanced Marine Engineering and Technology
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• 제30권1호
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• pp.65-72
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• 2006

Heat transfer augmentation in heat exchangers has received much attention in recent years, mainly due to energy efficiency and environmental considerations. Many active and Passive techniques are currently being employed in heat exchangers, with some inserts providing a cost-effective and efficient means of augmenting heat transfer. The Purpose of this paper is to determine the pressure loss and heat transfer characteristics of a heat exchanger using static mixing technology. Experimental measurements were taken on two set-ups: a single tube heat exchanger and a shell-tube heat exchanger with two static mixing inserts. It was concluded that the static mixing inserts resulted in an increase in the pressure loss and heat transfer characteristics as can be expected.

• 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.

• 수산해양기술연구
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• 제35권2호
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• pp.196-200
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• 1999

In the case that erosion and corrosion occurs in machinery and structure at the same time, the synergy effect by erosion-corrosion affects fatal effect to durability of machinery and structure. Therefore, in machinery and structure which use corrosion liquid, the study of the synergy effect of erosion-corrosion which affects metal material is requested. In this paper. the flow corrosion experiment about the effect of temperature change and liquid velocity change in sea water was carried out to study the characteristics of erosion-corrosion for tube material Cu heat exchanger The main results obtained are as follows. (1) Damage appearance of tube outside by erosion-corrosion becomes dull because electrode potentials of Cu tube is higher than electrode potential of STPG38 shell. (2) In the cooling system by sea water, the weight loss rate of Cu at tube outside liquid temperature of $70^{\circ}C$ is higher than that of temperature of $20^{\circ}C$. (3) In cooling system by sea water, the weight loss rate of Cu at liquid velocity of 5.1m/s is higher than that of velocity of 1.47m/s. But as the testing time passed, the weight loss rate of Cu at velocity of 5.1m/s is almost steady and becomes dull at velocity of 1.47m/s.

• 에너지공학
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• 제10권4호
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• pp.299-309
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• 2001

본 원통다관형 열교환기 설계 코드는 기존에 적용된 Bell-Delaware법 보다 한 차원 발전된 유동 해석법을 적용하여 좀더 정확하고 향상된 열교환기를 설계 하고자 한다. 열교환기 설계에 영향을 미치는 주요한 인자들에 대한 특성 및 설계 범위를 나타내었다. 유동 분율을 구하기 위한 유동 해석(Stream analysis)법에 대한 개략적인 소개와 열교환기 설계를 위한 순서도를 나타내었다. 설계 코드의 성능평가를 위하여 Delaware09, Delaware10, DongHwa, ANL에 대한 실험결과와 성능 비교를 수행하였다. 그 결과 열전달 및 압력 손실 예측치의 대부분이 $\pm$30% 이내에 만족함을 보였으나, 압력손실 부분에서는 전체적으로 과예측 결과를 나타내었다.

• 대한기계학회논문집
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• 제14권1호
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• pp.251-258
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• 1990

본 연구에서는 제 1보에서 다루었던 프로세스 해석의 결과들을 토대로 하여 열교환기의 최적 설계를 행하는데 주력하였다. 먼저, 열교환기의 최적 설계를 행하 는데 주력하였다. 먼저, 열교환기의 열설계에 필요한 CO$_{2}$와 Natrium의 물성치 및 열전달에 관한 기존의 실험식들을 여러문헌으로부터 연구 검토한 후 프로그램에 편 리하게 이용할 수 있도록 전산화 하였으며, 열교환기의 설계시 필요한 전체 경비의 최 소화를 기하는 방향으로 최적화된 설계인자들을 결정하도록 시도하였고 또한 최적화된 프로그램을 개발함으로써 인력, 외화 및 에너지 절감의 효과를 얻고자 하였다.