• 한국태양에너지학회 논문집
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• 제22권2호
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• pp.11-17
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• 2002

This paper is concerned with the development of a new method for making, separating ice and storage floated ice by installing an evaporation plate at under-water within a storage tank. In a conventional harvest-type ice storage system, a tank saves ice by separating an ice from an installed evaporation plate, which is located above an ice storage tank as an ice storage system. Developed new harvest-type method shows good heat transfer efficiency than a convectional method. It is because the evaporation panel is directly contacted with water in a storage tank. Also, at a conventional system a circulating pump, a circulating water distributor and a piping are installed, however these components are not necessary in a new method. In this study ice storage systems are experimentally investigated to study the charge and discharge of thermal energy. The results show the applicable possibility and performance enhancement of a new type.

• 한국산학기술학회논문지
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• 제21권11호
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• pp.86-93
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• 2020

국내 사회기반 시설물의 경우 70년대 이후로 건설되어 향후 신규건설에 대한 수요보다 유지보수에 대한 수요가 크게 증가할 것으로 전망된다. 더욱이 경주지진과 포항지진 이후로 과거 시공된 시설물의 내진성능에 대한 평가 및 보수 보강 사업이 이루어지고 있다. 본 연구에서는 보강공법 중 L형 GFRP 외부부착공법을 대상으로 하여 시험체를 설계하고, 에폭시와 화약식 타정 총으로 압력 핀을 시공하는 방법으로 외부부착된 L형 GFRP Plate의 보강효과를 확인하기 위하여 4점 휨 시험을 수행하였다. 실험결과를 바탕으로 L형 GFRP Plate의 보강효과를 확인하고, 국내의 "복합신소재시스템에 의한 철근콘크리트구조물의 보강설계 및 시공 지침서"에 따라 L형 GFRP 외부부착공법이 적용된 보의 거동에 대하여 평가하고 에폭시와 압력 핀을 조합하여 시공하는 부착방법의 효용성을 평가하였다. 실험 결과를 분석한 결과 지침에 따른 설계는 부재의 강도를 잘 예측하는 것으로 나타났으나, GFRP Plate 보강재의 손상을 동반하는 고정법의 사용으로 인하여 설계가정의 조건을 만족하는 파괴가 일어나지 않는 것으로 분석하였다.

• 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.

• 한국분무공학회지
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• 제15권2호
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• pp.83-93
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• 2010

Feedwater heaters of many nuclear power plants have recently experienced severe wall thinning damage, which will increase as operating time progresses. Several nuclear power plants in Korea have experienced wall thinning damage in the area around the impingement baffle inside feedwater heater installed downstream of the turbine extraction stream line. At that point, the extract steam from the turbine is two phase fluid at high temperature, high pressure, and high speed. Since it flows to reverse direction after impinging the impingement baffle, the shell wall of feedwater heaters may be affected by flow-accelerated corrosion. In this paper, to compare degree of shell wall thinning mitigation rate to squared type with mitigation rate of other type baffle plate, four different types of impingement baffle plate-squared, curved, mitigating type and multi-hole type-applied inside the shell. With these comparison data, this paper describes operation of experiments and numerical analysis which is composed similar condition with real feed water heater. And flow visualization is operated for verification of experiments and numerical analysis. In conclusion, this study shows that mitigating type and multi-hole type baffle plate are more effective than other baffle plate about prevention of pressure concentration and pressure value decrease.

• Steel and Composite Structures
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• 제32권4호
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• pp.497-507
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• 2019

Exposed column base connections are used in low- to mid-rise steel moment resisting frames. This paper is to investigate the effect of the base plate thickness on the exposed column base connection strength, stiffness, and energy dissipation. Five specimens with different base plate thickness were numerically modelled using ABAQUS software. The numerical model is able to reproduce the key characteristics of the experimental response. Based on the numerical analysis, the critical base plate thickness to identify the base plate and anchor rod yield mechanism is proposed. For the connection with base plate yield mechanism, the resisting moment is carried by the flexural bending of the base plate. Yield lines in the base plate on the tension side and compression side are illustrated, respectively. This type of connection exhibits a relatively large energy dissipation. For the connection with anchor rod yield mechanism, the moment is resisted through a combination of bearing stresses of concrete foundation on the compression side and tensile forces in the anchor rods on the tension side. This type of connection exhibits self-centering behavior and shows higher initial stiffness and bending strength. In addition, the methods to predict the moment resistance of the connection with different yield mechanisms are presented. And the evaluated moment resistances agree well with the values obtained from the FEM model.

• Tribology and Lubricants
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• 제16권6호
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• pp.440-447
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• 2000

It's a tendency to strengthen related international laws as the importance on marine oil pollution recently becomes the issue. According to the regulation of IMO, oil discharge from ships is allowed under 15 ppm only and oil filtering equipment is essential. However, for large ships using heavy fuel oil of over S.G 0.98 and viscosity 380 cSt and system oil, it has been in difficulty to process with existing filtering type of oily water separator. Oily water pre-separator of laminated plate type which is one of gravity type separator has very simple structure and it also makes easier to maintain and repair. In another words, it fits well to process large amount of rich oil with high specific gravity. In this paper, oily water pre-separator of laminated plate type has been studied. The function of emulsified oil and 4 different types of oil have been analyzed and each character has been investigated and proved by experiments. As the result of it, the efficiency of separating oil water has been advanced by 10% in case equipped with pre-separator. In addition, the higher temperature is and the more laminated plate has, it turns out to be getting more effect.

• 에너지공학
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• 제24권4호
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• pp.48-54
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• 2015

본 연구에서는 야외용 가스보일러 형상에 따른 연소판을 열응력 결과를 통해 분석하였다. 정상상태 모드로 계산한 결과, 최대 응력 및 변형은 A형상과 B형상에서 각각 666.8MPa, 0.20476mm로 분석되었다. 변형은 연소판 중심에서 바깥쪽으로 갈수록 증가하는 경향을 보였다. 또한, 8가지 형상 중에서 최대 응력과 변형은 F와 C형상이 가장 안전함을 각각 보였다. 따라서, 8가지 형상 중에서 F형상이 강도 및 안전성 측면에서 가장 우수하다고 판단되었으며, 가스보일러의 연소판 형상에 따른 계산된 결과를 분석함으로서 보일러 시스템에 대한 안전한 구성요소 변수를 실질적으로 적용할 수 있는 모델을 설계할 수 있게 되었다.

• Steel and Composite Structures
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• 제43권1호
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• pp.107-116
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• 2022

This paper presents results of numerical studies completed on unreinforced and doubler plate reinforced Elliptical Hollow Section (EHS) T-joints subjected to axial compressive loading on the brace member. Non-linear finite element (FE) models were developed using the finite element code, ABAQUS. Available test data in literature was used to validate the FE models. Subsequently, a parametric study was carried out to investigate the effects of various geometrical parameters of main members and reinforcement plates on the ultimate capacity of reinforced EHS T-joints. The parametric study found that the reinforcing plate significantly increases the ultimate capacity of EHS T-joints up to twice the capacity of the corresponding unreinforced joint. The thickness and length of the reinforcing plate have a positive effect on the ultimate capacity of Type 1 joints. This study, however, found that the capacity of Type 1 orientation is not dependent on the brace-to-chord diameter ratio. As for type 2 orientations, the thickness and length of the reinforcement have a minimal effect on the ultimate capacity. A new design method is introduced to predict the capacity of the reinforced EHS T-joints Type 1 and 2 based on the multiple linear regression analyses.

• International Journal of Aeronautical and Space Sciences
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• 제14권1호
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• pp.19-29
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• 2013

This paper deals with the study of buckling, vibration, and parametric instability characteristics in a damaged cross-ply and angle-ply laminated plate like beam under in-plane harmonic loading, using the finite element approach. Damage is modelled using an anisotropic damage formulation, based on the concept of reduction in stiffness. The effect of damage on free vibration and buckling characteristics of a thin plate like beam has been studied. It has been observed that damage shows a strong orthogonality and in general deteriorates the static and dynamic characteristics. For the harmonic type of loading, analysis was carried out on a thin plate like beam by solving the governing differential equation which is of Mathieu-Hill type, using the method of multiple scales (MMS). The effects of damage and its location on dynamic stability characteristics have been presented. The results indicate that, compared to the undamaged plate like beam, heavily damaged beams show steeper deviations in simple and combination resonance characteristics.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 춘계학술대회
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• pp.2135-2140
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• 2004

This study represented experimental research on the flat plate solar collector. For the flat plate Solar system, it is sensitive of the Global radiation. In Actually, it suppose to be dependent on the direct radiation. Also, the existing method's factors are depend upon Global radiation in the flat plate collector system. therefore it needs which is depend upon direct radiation. In this experiment, the flat plate collector is used for obtaining the method's factors of the direct radiation. As a result, the correct $({\tau}{\alpha})_e$ is found out for practical value.