• 한국원자력학회:학술대회논문집
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• 한국원자력학회 2001년도 추계학술발표회요약집
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• pp.107-107
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• 2001

• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제18권3호
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• pp.257-268
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• 2014

The objective of the present study is to investigate thermal diffusion and radiation effects on unsteady MHD flow past a linearly accelerated vertical porous plate with variable temperature and also with variable mass diffusion in presence of heat source or sink under the influence of applied transverse magnetic field. The fluid considered here is a gray, absorbing/emitting radiation but a non-scattering medium. At time t > 0, the plate is linearly accelerated with a velocity $u=u_0t$ in its own plane. And at the same time, plate temperature and concentration levels near the plate raised linearly with time t. The dimensionless governing equations involved in the present analysis are solved using the closed analytical method. The velocity, temperature, concentration, skin-friction, the rate or heat transfer and the rate of mass transfer are studied through graphs in terms of different physical parameters like magnetic field parameter (M), radiation parameter (R), Schmidt parameter (Sc), Soret number (So), Heat source parameter (S), Prandtl number (Pr), thermal Grashof number (Gr), mass Grashof number (Gm) and time (t).

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.145-148
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• 2003

Thermal characteristics according to the bearing preload arc studied for the four type spindles with high frequency motor. For the analysis. three dimensional models are built considering heat transfer characteristics such as natural and forced convection coefficients, Bearing and motor are main heat generation, and heat generation by ball bearings as a function of load. viscosity and gyroscopic moment effect are considered. Unsteady-state temperature distributions and thermal displacements according to the bearing preload are analyzed by using the finite clement method.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2009년도 하계학술발표대회 논문집
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• pp.973-978
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• 2009

In this study, the thermal environment characteristics of On-Off control and thermal difference proportional control method in floor radiant heating system were researched by computer simulation. For the analysis of unsteady heat transfer phenomena in household, the method of using electrical equivalent R-C circuit is applied, and radiation heat transfer between panel, ceiling and walls in household is calculated by enclosure analysis method. The parametric study on two control methods, conventional on-off control and temperature error based time control(T.E.B.T.C.) method, are performed to compare thermal heating control performances, respectively.

• 대한조선학회논문집
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• 제32권2호
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• pp.75-83
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• 1995

생산현장의 판굽힘가공 자동화를 위한 기초연구로서 강판의 선상가열 변형을 역학적 측면에서 고찰하고 3차원 비선형 과도 열탄소성 유한요소해석을 통한 수치 시뮬레이션을 시도하였다. 가스토치에 의해 가열되는 평판의 비정상 열전달 문제를 해석하며 온도분포의 시간이력을 계산하였고 이를 바탕으로 평판의 과도 열변형과정을 해석하였으며 그 결과를 상세히 고찰하였다.

• International Journal of Air-Conditioning and Refrigeration
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• 제6권
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• pp.1-13
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• 1998

The basic heat transfer process that occurs in a building can best be illustrated by an electrical circuit network. Present paper reports the dynamic simulation of annual energy consumption in an office building by the thermal resistance capacitance network method. Unsteady thermal behaviors and annual energy consumption in an office building were examined in detail by solving the simultaneous circuit equations of thermal network. The results are used to evaluate the accuracy of the modified BIN method for the energy consumption analysis of a large building. Present thermal resistance-capacitance method predicts annual energy consumption of an office building with the same accuracy as that of response factor method. However, the modified BIN method gives 15% lower annual heating load and 25% lower cooling load than those from the present method. Equipment annual energy consumptions for fan, boiler and chiller in the HVAC system are also calculated for various control systems as CAV, VAV, FCU+VAV and FCU+CAV. FCU+CAV system appears to consume minimum annual energy among them.

• Nuclear Engineering and Technology
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• 제53권6호
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• pp.1731-1735
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• 2021

The operation of the nuclear reactor requires accurate and fast methods and techniques for analysing its kinetics. These techniques become even more important when the MOX-fuel is used due to the lower value of delayed neutron fraction 𝛽 for ²³⁹Pu. Based on a Birth-and-Death process review, the mathematical model of thermal reactor core has been proposed different from existing ones. The analytical method for thermal point-reactor parameters evaluation is described within this work. The proposed method is applied for analysis of the unsteady transient processes taking place in a thermal reactor at its start-up or shutdown power change, as well as during small accidental power variation from the rated value. Theoretical determination of MASURCA reactor core reactivity through the analysis of experimental data on neutron time spectra was made.

• 한국항공우주학회지
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• 제32권8호
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• pp.91-100
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• 2004

경사기능재료 판에 대한 열탄성 변형과 응력 해석을 위해 Green 함수 방법이 채택되었다. 3 차원 비정상 온도분포에 대한 해는 적층판 이론에 의해 얻어진다. 열탄성 문제에 대한 기본 방정식은 각각 평면외 (out-plane) 변형과 평면내 (in-plane) 힘에 의해 유도되었다. 굽힘과 평면내 힘에 의한 열탄성 변형과 응력분포는 Galerkin 방법에 근거한 Green 함수를 이용하여 해석하였다. 열탄성 변형과 응력분포 해석을 위한 Galerkin Green 함수의 특성함수들은 사각판의 제차 경계조건을 만족시키는 허용함수들의 급수 형태로 근사화되었다. 단수지시된 사각 판에 대한 수치해석이 수행되었으며, 정사기능재료의 물성치가 판의 비정상 열탄성 거동에 미치는 영향이 검토되었다.

• KIEAE Journal
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• 제5권1호
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• pp.27-33
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• 2005

Global efforts have made to reduce energy consumption and $CO_2$ gas emission. One of the weakest parts for energy loss through the whole building components is building envelopes. Lots of technologies to increase the thermal performance of building envelopes have been introduced in recent year. Transparent Insulation Wall(TIW) is a new technology for building insulation and has been function both solar transmittance and thermal insulation. A mathematical model of a Transparent Insulation Wall equipped with south wall was proposed in order to predict thermal performance under varying climates(summer and winter). Unsteady state heat transfer equations were set up using an energy balance equation and solved using Gauss-Seidel iteration solution procedure. The thermal performance of the TIW determined from a wall surface and air layer temperature, non-airconditioned room temperature and air conditioning load. As a result, this numerical study shows that the TIW is effective in an air conditioning load reduction. Further experimental study is required to establish complete TIW system.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2004년도 추계 학술대회논문집
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• pp.221-225
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• 2004

Evaluation of turbulence models is performed for a better prediction of thermal stratification in an upper plenum of a liquid metal reactor by applying them to the experiment conducted at JNC. The turbulence models tested in the present study are the two-layer model, the $\kappa-\omega$ model, the v2-f model and the low-Reynolds number differential stress-flux model. When the algebraic flux model or differential flux model are used for treating the turbulent heat flux, there exist little differences between turbulence models in predicting the temporal variation of temperature. However, the v2-f model and the low-Reynolds number differential stress-flux model better predict the steep gradient o( temperature at the interface of thermal stratification, and only the v2-f model predicts properly the oscillation of temperature. The LES Is needed for a better prediction of the amplitude and frequency of the temperature fluctuation.