• 한국초전도저온공학회:학술대회논문집
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• 한국초전도저온공학회 2002년도 학술대회 논문집
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• pp.31-34
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• 2002

In this study, thermal analysis of a thermal capacitor, which is used to cool the current lead in conduction-cooled superconducting systems, was done. The temperature difference across a thermal capacitor was calculated by using heat conduction equation. Effect of heat load, total thickness, height and length of a thermal capacitor on the temperature difference were show. Using the results in this work, total thickness and heat height of a thermal capacitor can be determined for given heat load and given temperature difference. This work can be used practically in design for every superconduction system using a current lead.

• Journal of Ship and Ocean Technology
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• 제8권3호
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• pp.50-60
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• 2004

In this paper, a continuum-based design sensitivity analysis (DSA) method is developed for the weakly coupled thermo-elasticity problems. The temperature and displacement fields are described in a common domain. Boundary value problems such as an equilibrium equation and a heat conduction equation in steady state are considered. The direct differentiation method of continuum-based DSA is employed to enhance the efficiency and accuracy of sensitivity computation. We derive design sensitivity expressions with respect to thermal conductivity in heat conduction problem and Young's modulus in equilibrium equation. The sensitivities are evaluated using the finite element method. The obtained analytical sensitivities are compared with the finite differencing to yield very accurate results. Extensive developments of this method are useful and applicable for the optimal design problems incorporating welding and thermal deformation problems.

• 대한기계학회논문집B
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• 제20권2호
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• pp.741-751
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• 1996

The coupled conduction and convection heat transfer from the protruding heat source in a vertical channel is numerically investigated. Conjugate solution of the two-dimensional energy equation is obtained for the incompressible air flow over the rectangular block with local heat source. It was found that several recirculation zones and separation bubble near the block were related to Re and Gr. And the results show that fractions of the heat transfer through each of the block face, maximum temperature of the block and the relative effect of each parameter on the maximum temperature and heat transfer.

• 설비공학논문집
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• 제7권2호
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• pp.266-275
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• 1995

A numerical investigation on the conduction-natural convection-surface radiation conjugate heat transfer in the enclosure having substrate and chips has been performed. A 2-dimensional simulation model is developed by considering heat transfer by conduction, convection and radiation. The solutions to the equation of radiative transfer are obtained by the discrete ordinates method using S-4 quadrature. The effects of Rayleigh number and the substrate-fluid thermal conductivity ratio on the cooling of chip are analyzed. The result shows that radiation is the dominant heat transfer mode in the enclosure.

• 대한수학회지
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• 제48권2호
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• pp.311-327
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• 2011

This paper is devoted to simplified Tikhonov regularization for two kinds of parabolic equations, i.e., a sideways parabolic equation, and a two-dimensional inverse heat conduction problem. The measured data are assumed to be known approximately. We concentrate on the convergence rates of the simplified Tikhonov approximation of u(x, t) and its derivative $u_x$(x, t) of sideways parabolic equations at 0 $\leq$ x < 1, and that of two-dimensional inverse heat conduction problem at 0 < x $\leq$ 1, respectively.

• Journal of Advanced Marine Engineering and Technology
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• 제19권2호
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• pp.10-19
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• 1995

Heat trnasfer for absorbing and emitting media in laminar layer along the cylinders has been analyzed. Governing equation are transformed to local nonsimilarity equations by the dimensional analysis. The effects of the Stark number, Prandtl number, Optical radius and wall emissivity are mainly investigated. For the formal solution a numerical integration is performed and the results are compared with those obtained by P-1 and P-3 approximation. The results show that boundary layers consist of conduction-convection-radiation layer near the wall and convection-radiation layer far from the wall. As the Stark number of wall emissivity increases the local radiative heat flux is increased. The Pradtl number or curvature variations do not affect the radiative heat flux from the wall, but The Prandtl number or wall emissivity variations affect the conduction heat flux. Consequently the total heat flux from the wall are affected by the Prandtl number or wall emissivity variation.

• 한국안전학회지
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• 제23권3호
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• pp.87-92
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• 2008

시간에 불연속성인 유한요소법이 열전도 방정식에 적용하였다. 근사값은 고정된 시간에 공간변수에는 연속이며 그러나 각 시간 구간에서는 시간변수에 불연속을 허용하였다. 이 유한요소법은 지금까지 많이 알려진 재래식 유한요소해석에 보다 해의 수렴속도가 빠르고 해를 쉽게 얻을 수 있으며 지반이 동결된 동상지반과 같이 복잡한 공학문제와 같은 동적 경계치 문제에 쉽게 접근할 수 있었다. 다차원 문제에도 적용이 가능하며 본 연구에서는 일차원, 이차원 열전도 문제에 적용하였다. 결과 치를 해석해와 비교 검토하였다.

• East Asian mathematical journal
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• 제34권3호
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• pp.295-303
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• 2018

Gautam et al. [9] introduced the multivariable A-function, which is very general, reduces to yield a number of special functions, in particular, the multivariable H-function. Here, first, we aim to establish two very general integral formulas involving product of the general class of Srivastava multivariable polynomials and the multivariable A-function. Then, using those integrals, we find a solution of partial differential equations of heat conduction at zero temperature with radiation at the ends in medium without source of thermal energy. The results presented here, being very general, are also pointed out to yield a number of relatively simple results, one of which is demonstrated to be connected with a known solution of the above-mentioned equation.

• 한국화재소방학회논문지
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• 제11권2호
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• pp.19-24
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• 1997

화재 모델에서 구한 가스 의 온도를 이용하여 비정상 열전도 방정식의 수치해석을 하면 유한 제어 체적을 계산할 수 있으며 가열 온도와 저감율로 열에 의한 압축 및 휨 강도의 저하값을 계산할 수 있다. 또한 이 방법을 이용하여 콘크리트 구조물(기둥, 보등)의 안전성 평가에 잘 적용할수 있었다.할수 있었다.

• 한국포장학회지
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• 제12권1호
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• pp.45-53
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• 2006

Thermal insulation is used in a variety of applications to protect temperature sensitive products from thermal damage. Several factors affect the performance of insulation packages. Among these factors, the thermal resistance of the insulating wall is the most important factor to determine the performance of the insulating package. In many cases, insulating wall consists of multi-layered structure and the heat transfer through this structure is a very complex process. In this study, an one-dimensional mathematical model, which includes all of the heat transfer principles covering conduction, convection and radiation in multi-layered structure, were developed. Based on this model, several heat transfer phenomena occurred in the air space between the layer of the insulating wall were investigated. From the simulation results, it was observed that the heat transfer through the air space between the layer were dominated by conduction and radiation and the low emissivity of the surface of each solid layer of the wall can dramatically increase the thermal resistance of the wall. For practical use, an equation was derived for the calculation of the thermal resistance of a multi-layered wall.