• Progress in Superconductivity
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• 제12권1호
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• pp.17-22
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• 2010

Distribution of local critical temperature and current density in $YBa_2Cu_3O_{7-\delta}$ (YBCO) coated conductors was analyzed using a Low-temperature Scanning Laser Microscopy (LTSLM). We prepared YBCO coated conductors of various bridge types to study the spatial distribution of critical temperature and current density in single and multi bridges. An LTSLM system was modified for a detailed two-dimensional scan without shifting of the sample. We observed a spatial distribution of the critical temperature from the bolometric response, which arises from a focused laser beam at the sample near the superconducting transition. Also we studied the relation between the critical temperature and the current density.

• 대한기계학회논문집
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• 제14권2호
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• pp.393-398
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• 1990

A method is proposed which can be used to obtain the fibesr content distribution of compression molded long fiber-reinforced thermoplastic sheet for nonisothermal state. The fiber is modelled to be a sphere. Once the one-dimensional unsteady state heat conduction equation in solved, the mean temperature in defined across the thickness direction. The viscosity of matrix is determined with the mean temperature. Using the obtained viscosity, two-dimensional sheet0like part compression molding is simulated with the finite element method. Comparison with experiments shows that the method accurately predicts the distribution.

• 한국자동차공학회논문집
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• 제11권6호
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• pp.93-100
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• 2003

This paper describes the thermoelastic instability arising from friction heat generation in braking and proposes the finite element methods to predict the variation of temperature and thermal deformation. In a conventional disc brake analysis, heat generation is only related with wheel speed and friction material and the interface pressure between disc and pad is assumed constant. But under dynamic braking conditions, the frictional heat causes the thermoelastic distortion that leads to more concentrated contact pressure distribution and hence more and more non-uniform temperature. In this paper, to complete the solution of the thermomechanically coupled problem, the linear relation model between pressure and temperature is proposed and demonstrated in examples of a simple two dimensional contact problem. And the two dimensional model has been extended to an annular three dimensional disc model in order to consider more realistic geometry and to provide a more accurate critical speed for automotive brake systems.

• 대한조선학회지
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• 제14권4호
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• pp.15-22
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• 1977

In this paper, two dimensional theoretical solutions of temperature distribution and thermal stress due to tandem cooling in an infinite plate were studied. Temperature distribution and thermal stress were calculated by numerical integration. Calculated temperature distributions were in good agreement with the result of the experiments by Park, and calculated thermal stresses were in good agreement with physical phenomena. This solutions could be applied to the practical tandem cooling operations.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회B
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• pp.2334-2339
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• 2008

This paper proposes an improved mathematical model for predicting the frosting behavior on a two-dimensional fin considering the heat conduction of heat exchanger fins under frosting conditions. The model consists of laminar flow equation in airflow, diffusion equation of water vapor for frost layer, and heat conduction equation in fin, and these are coupled together. In this model, the change in three-dimensional airside airflow caused by frost growth is accounted for. The fin surface temperature increased toward the fin tip due to the fin heat conduction. On the contrary, the temperature gradient in the airflow direction(x-dir.) is small throughout the entire fin. The frost thickness in the direction perpendicular to airflow, i.e. z-dir., decreases exponentially toward the fin tip due to non-uniform temperature distribution. The rate of decrease of heat transfer in the airflow direction is high compared to that in the z-direction due to more decrease in the sensible and latent heat rate in x-direction.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집D
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• pp.390-395
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• 2001

Cooling characteristics using convection and conduction heat transfer in a parallel channel with extruding heat sources are studied numerically. A two-dimensional model has been developed for numerical prediction of transient, compressible, viscous, laminar flow, and conjugate heat transfer between parallel plates with uniform block heat sources. The finite volume method is used to solve this problem. The considered assembly consists of two channels formed by two covers and one PCB which has three uniform heat source blocks. Five different cooling methods are considered to find efficient cooling method in a given geometry and heat source. The velocity and temperature fields, local temperature distribution along surface of blocks, and the maximum temperature in each block are obtained.

• Coupled systems mechanics
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• 제8권3호
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• pp.219-245
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• 2019

The present research deals in two dimensional (2D) transversely isotropic magneto generalized thermoelastic solid without energy dissipation and with two temperatures due to time harmonic sources in Lord-Shulman (LS) theory of thermoelasticity. The Fourier transform has been used to find the solution of the problem. The displacement components, stress components and conductive temperature distribution with the horizontal distance are calculated in transformed domain and further calculated in the physical domain numerically. The effect of two temperature are depicted graphically on the resulting quantities.

• 한국광학회:학술대회논문집
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• 한국광학회 1990년도 제5회 파동 및 레이저 학술발표회 5th Conference on Waves and lasers 논문집 - 한국광학회
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• pp.79-81
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• 1990

Temperature distribution of laser diode chip mounted on ideal heat kink was calculated by numerical analysis. In numerical analysis, infinite difference method and Gauss-Scidel iteration was adopted on the basis of two dimensional heat conduction phenomena. As a result, temperature increase of active medium of laser diode driven at 60mA was calculated to be 1.47$^{\circ}C$

• 터널과지하공간
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• 제14권4호
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• pp.287-294
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• 2004

지하암반 냉동저장고 주변의 온도분포를 예측하기 위하여, FLAC을 이용한 2차원 및 3차원 수치해석을 수행하였다. 수치해석 수행 시 암반 열물성에 대한 지하수 및 동결잠열의 영향을 고려하였으며, 2차원 및 3차원 수치해석 결과와 5년간의 지하암반 온도계측 자료를 비교하였다. 2차원 수치해석 결과 실험실 물성을 이용한 경우는 계측 결과와 큰 오차를 나타내었으며, 지하수 부피비 20% 및 동결잠열을 고려한 수치해석 결과가 계측 결과와 가장 작은 오차를 나타내었다. 하지만, 냉동기 가동시간이 증가하면서 지표면으로의 열 유동의 영향으로 커지는 오차는 커지는 경향을 나타내었다. 지표면의 영향을 고려하는 3차원 수치모델을 정립하여 수치해석을 수행한 결과, 지하수 및 동결잠열의 영향을 고려한 수치모델이 계측 결과가 잘 일치하는 경향을 나타내었다.

• Progress in Superconductivity
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• 제13권1호
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• pp.28-33
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• 2011

Distribution of the local critical temperature and current density in YBCO coated conductors were analyzed using Low-temperature Scanning Laser and Hall Probe Microscopy (LTSLHPM). We prepared YBCO coated conductors of various bridge types to study the spatial distribution of the critical temperature and the current density in single and multi bridges. LTSLHPM system was modified for detailed linescan or two-dimensional scan both scanning laser and scanning Hall probe method simultaneously. We analyzed the local critical temperature of single and multi bridges from series of several linescans of scanning laser microscopy. We also investigated local current density and hysteresis curve of single bridge from experimental results of scanning Hall probe microscopy.