• 한국기계가공학회지
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• 제11권3호
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• pp.154-159
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• 2012

For numerical analysis of the plate heat exchanger, a lot of time are required in modeling work and calculation. Whereas, this paper was purposed to identify characteristic of the plate heat exchanger through simplification of modeling by interpreting the numerical analysis proximity with the actual model. This study was also examined temperature difference between inlet side and outlet side, inner pressure drop, heat transfer area of plate and change of heat transfer coefficient on the plate depending on the inner corrugation angle and corrugation pitch of a herring bon pattern of the plate heat exchanger among chevron types of the plate exchanger.

• Tribology and Lubricants
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• 제25권6호
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• pp.374-380
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• 2009

This paper presents the stress and displacement characteristics of oil pipe using the finite element analysis. Displacement in axial direction and von Mises stress of a pipe were analyzed with three design factors, which are the pipe thickness, the corrugation pitch and the corrugation height, under uniform oil pressure. The FE computed results are presented between a conventional round pipe and a rectangular pipe, which is manufactured in this study. The computed FE results show that maximum displacement in axial direction and von Mises stress of pipe are increased linearly as the oil pressure increases. Also, they are increased linearly as the corrugation pitch, corrugation height and pipe thickness increases. von Mises stress of a rectangular pipe at the edge increases sharply compared with that of a conventional round pipe. Therefore, the strength of rectangular pipe is superior to that of a conventional round pipe.

• 대한기계학회논문집B
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• 제34권11호
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• pp.965-973
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• 2010

본 연구에서는 입구영향과 주름높이가 고려된 판형열교환기의 유동 및 열전달특성을 수치적으로 해석하였다. 여러 개의 단위셀을 연결한 다중셀에 입구부와 출구부가 부착된 모델을 기본으로 입구부의 길이변화($L_{cell}{\sim}5L_{cell}$)에 따른 모델과 P/H비 변화($2{\leq}P/H{\leq}4$)에 따른 모델에 대하여 수치해석을 수행하였다. 수치조건은 쉐브론각 $15^{\circ}$, 주름피치 24mm이며, $1,000{\leq}Re{\leq}10,000$이다. 마찰인자는f=$CRe^m$의 형태로, Colburn j 계수는 j=$CRe^m$의 형태로 상관관계식을 제시하였다. 이러한 상관관계식은 향후 판형열교환기 설계시에 기초자료로 활용될 수 있을 것으로 판단된다.

• 대한조선학회논문집
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• 제59권2호
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• pp.109-117
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• 2022

Membrane panels are installed in LNG cargo-hold in order to endure extremely low temperature LNG. Although there are several types of membranes around the world, Korean LNG cargo containment system is developing to accomplish technology independence from the other countries. The membrane panel of Korean LNG cargo containment system is composed of corrugation and flat sheets which are arranged asymmetrically. It is very important to reduce the number of the type of corrugation sheet because a mold is required as much as the type of the corrugation sheet. Therefore, we proposed an optimization method to minimize the type of the corrugation sheet. For this method, the number of pitches, which is the distance between the centers of two corrugation sheets should be minimized. We also developed optimized arrangement procedure of the flats simultaneously. Finally, the developed optimization program is applied to 174K LNG cargo hold, and the minimum pitch size is found.

• 한국가스학회지
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• 제15권4호
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• pp.39-43
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• 2011

본 연구에서는 가스배관용 플렉시블 조인트의 응력과 변형거동 특성을 유한요소법으로 해석하였다. 이러한 특성결과는 나선 주름관이나 직각 주름관 및 평면관으로 구성된 플렉시블 조인트의 강도안전성을 고찰할 수 있다. FEM 계산결과에 의하면, 최적의 나선 주름관은 $4.7^{\circ}$의 경사각도와 1.5mm의 주름높이를 갖는 주름관 모델인것으로 나타났다. 또한, $90^{\circ}$의 주름을 갖는 직각 주름관 모델이 경사각도를 갖는 나선 주름관보다는 강도안전성이 더 우수한 것으로 나타났다. 따라서, 주름관의 강도안전성을 높이기 위해서는 주름관의 피치와 곡률반경을 줄이는 것이 바람직함을 알 수 있다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2006년도 추계학술대회 논문집
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• pp.1293-1298
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• 2006

A numerical analysis was performed to verify how much additional force is induced by short or long pitch rail corrugations in track. The rail corrugations assumed as sine wave having various pitches and depths. The variation of wheel force, displacement and acceleration of rail and sleeper was investigated. In the results, it was shown that each item of the investigation was increased as the pitches and depths become large. It is expected that the results of the parametric study can be used as a preliminary data for the determination of economical maintenance criteria for rail corrugation in the future

• 한국초전도ㆍ저온공학회논문지
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• 제25권4호
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• pp.32-39
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• 2023

One of the main problems faced in developing India's first HTS power cable was that of shrinkage in length of the double-walled vacuum-insulated cryostat. The shrinkage was due to the evacuation of the annular vacuum space which results in a shorter working cable length. This work reports experimentally observed contraction during evacuation and analyses corrugated pipes/bellows which house the cable core of HTS cables. The effect of corrugation geometry including length, corrugation pitch and depth, diameters of corrugated pipes and thicknesses of pipes is studied numerically to realize the degree of shrinkage due to vacuum as well as chill down. Finally, necessary length compensation and associated cost is determined to tackle the shrinkage issue.

• 대한기계학회논문집B
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• 제36권1호
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• pp.1-8
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• 2012

본 연구에서는 주름높이가 고려된 판형열교환기의 완전발달유동 및 열전달특성을 수치적으로 해석하였다. 여러 개의 단위셀(5개 또는 7개)을 연결한 다중셀에 입구부와 출구부가 부착된 모델을 기본으로 P/H비 변화($2.0{\leq}P/H{\leq}4.0$)에 따른 모델에 대하여 수치해석을 수행하였다. 작동유체는 물이며, 수치조건은 쉐브론각 $20^{\circ}$, $300{\leq}Re{\leq}1,500$이다. 그리고 마찰인자는 $f=CRe^m$의 형태로, Colburn 계수는 $j=CRe^m$의 형태로 상관관계식을 제시하였다. 수치해석 결과 완전발달유동은 세 번째 셀부터 시작되었으며, 누셀트수는 P/H비가 작을수록 큰 값을 나타냈다.

• 한국전산유체공학회지
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• 제9권2호
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• pp.18-22
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• 2004

Numerical investigation has been conducted to figure out flow behavior and pressure drop characteristics of spirally corrugated steel pipe which is widely used in civil, industrial and agricultural field owing to many advantages such as good corrosion resistance and durability, strength, easy and quick installation. Also the poly-ethylene coating spirally corrugated steel pipe has the long life under condition of sea water immerged. In the present study, flow behavior in the spirally corrugated pipe and influence of P/d/sub h/(ratio of wave pitch to hydraulic diameter) to pressure drop are investigated by CFD with various Reynolds number. And also friction factor is estimated by pressure drop obtained by flow analysis. According to computation results, the flow runs spirally up and down along the spiral corrugation in the vicinity of wall, but the effect of spiral corrugation disappears in core region of pipe. As P/d/sub h/ becomes small, more pressure drop occurs in spirally corrugated Pipe. Besides, friction factor augmentation becomes much larger as Re increases. In case of p/d/sub h/=0.38, Pressure drop and friction factor of spirally corrugated pipe are about four times larger than smooth pipe at Re: 1.46×10/sup 6/.

• 한국가스학회지
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• 제3권3호
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• pp.58-64
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• 1999

멤브레인 방식의 저장탱크 제작에서 가장 중요한 설계 파라메타인 멤브레인 유니트의 피치에 관한 응력거동 문제를 유한요소법을 사용하여 해석하였고, 이 결과를 기존의 피치설계치수와 비교 검토하였다. 본 연구에서 고려한 링 마디식 멤브레인의 경우 피치의 길이를 어떻게 설정하든지 초대형 탱크의 경우에서는 안전성 문제가 발생하지 않았다. 그러나 반복하중에 의한 피로강도가 문제되는 선박용 멤브레인의 경우에는 피치를 짧게 설계하는 것이 유리하다는 것을 보여주고 있다. 멤브레인 주름의 변형거동을 보면 주름의 높이 방향 변형이 폭에 비하여 $15{\~}50\%$ 정도 더 크게 발생하고, $-162^{\circ}C$의 초저온에 의한 변형은 액압에 의한 변형과 비교할 때 그리 크지는 않음을 보여준다.