• Transactions of the Korean Society of Mechanical Engineers
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• v.14 no.6
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• pp.1652-1660
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• 1990

Combined radiative-convective heat transfer in a hot gas tube flow has been investigated numerically and experimentally. In the numerical analysis, a standard k-.epsilon. model is used for the evaluation of turbulent shear stresses and spherical harmonics method with the Weighted Sum of Gray Gases Model for the solution of radiative transfer equation. In the experimental study measured are the velocity and temperature of the hot gas flow generated by the propane gas combustion, and tude wall heat flux distribution. Numerical results are compared with experimental ones and it is confirmed that P-3 provides quite reliable results in the analysis of the combined radiation-convection system.

• Journal of the Society of Naval Architects of Korea
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• v.39 no.2
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• pp.52-60
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• 2002

Line heating is a forming process which makes the curved surface with the residual strain created by applying heat source of high temperature to steel plate. in order to control the residual strain, it is necessary to understand not only conductive heat transfer between heat source and steel plate, but also temperature distribution of steel plate. In this paper we attempted to analyze is temperature distribution of steel plate by simplifying a line heating process to collision-effusive flux of high temperature and high velocity, and conductive heat transfer phenomenon. To analyze this, combustion in the torch is simplified to collision effusive phenomenon before analyzing turbulent heat flux. The distribution of temperature field between the torch and steel plate is computed through turbulent heat flux analysis, and the convective heat transfer coefficient between effusive flux and steel plate is calculated using approximate empirical Nusselt formula. The velocity of heat flux into steel plate is computed using the temperature distribution and convective heat transfer coefficient, and temperature field in the steel plate is obtained through conductive heat transfer analysis in which the traction is induced by velocity of heat flux. In this study, Finite Element Method is used to accomplish turbulent heat flux analysis and conductive heat transfer analysis. FEA results are compared with empirical data to verify results.

• Fire Science and Engineering
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• v.23 no.5
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• pp.133-137
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• 2009

The Fire Dynamics Simulator (FDS), a computational fluid dynamics model for fire simulation, was applied to propylene vertical wall fires, to confirm its accuracy in simulation of vertical wall fires. The temperature profiles at the center of the burner obtained for mass loss rates per unit area in the range of $7.0{\sim}29.29g/m^2-s$ were compared with those of experiment. Comparisons of the heat flux distributions along the vertical centerline on the wall surface were made with the measurements. It was shown that the computed temperature profiles were in good agreement with the experiment. It was also noted that the peak temperature near the wall was underpredicted, the heat flux was too high compared with the measurements, and hence improvements are required for FDS in simulation of the vertical wall fires.

• Fire Science and Engineering
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• v.13 no.4
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• pp.20-29
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• 1999

This paper describes the smoke filling process of a fire field model based on a self-developed SMEP(Smoke Movement Estimating Program) code to the simulation of fire induced flows in the two types of atrium space containing a ceiling heat flux. The SMEP using PISO algorithm solves conservation equations for mass, momentum, energy and species, together with those for the modified k- epsilon turbulence model with buoyancy term. Compressibility is assumed and the perfect gas law is used. The results of the calculated upper-layer average temperature and smoke layer interface height has shown reasonable agreement compared with the zone models. The zone models used are the CFAST developed at the Building and Fire Research Laboratory NIST U.S.A. and the NBTC one-room of FIRECALC developed at CSIRO, Australia. The smoke layer interface heights that are important in fire safety were not as sensitive as the smoke layer temperature to the nature of ceiling heat flux condition.

• Transactions of the Korean Society of Mechanical Engineers
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• v.7 no.1
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• pp.103-109
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• 1983

본 논문은 저온용 원통형 저장 탱크를 2층으로 된 적층형 복합재료로 가정하여 각 층의 온도분포 를 해석하였다. 이 중공 원통의 외벽에서는 원주방향으로 임의의 열유속을 받고, 주위 온도는 주 기적으로 변하며 내외벽에서는 대류가 일어나고, 탱크벽의 초기온도 분포는 임의의 함수라는 가 정하에 Fourier cosine 변환과 Green 함수를 도입하여 해석하였다.

• 한국태양에너지학회:학술대회논문집
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• 2012.03a
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• pp.274-279
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• 2012

Daegu Solar Power Tower Plant of 200 kW thermal capacity was developed for the first time in Korea, 2011. Measurement of the heat flux distribution is essential to evaluate the solar energy concentrated by reflectors and to design a suitable receiver. The flux mapping technique, which uses a radiometer and a diffuse plate, is common for measurement of the heat flux distribution. Because the solar power tower plant has a wide concentration area, the flux mapping technique using a fixed diffuse plate is difficult to apply. Therefore, the flux distribution in the solar power tower plant should be measured by the flux mapping technique using a small moving bar. In this study, we measured flux distributions with the moving-bar system developed at the KIER solar furnace and evaluated its applicability for the solar power tower plant.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.669-670
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• 2013

• Proceedings of the Korean Nuclear Society Conference
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• 1996.05b
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• pp.391-396
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• 1996

내부부수로, 벽면부수로, 모서리부수로를 포함하는 가압경수로형 원자로의 핵연료집합체를 모의하는 3$\times$3 봉다발을 모델로 수치해석을 통해 봉다발 주변의 유동특성을 알아보고 각 봉에서의 원주방향 위치에 따른 국소열전달 특성에 관해 고찰하였다. 봉다발에서 열전달계수의 분포는 벽면영향으로 인한 각 부수로에서의 유속분포와 밀접한 관계가 있으며 내부부수로에 인접한 봉에서 가장 높았고, 그 다음이 벽면부수로, 모서리부수로에 인접한 봉에서는 가장 작게 나타났다. 현재 핵연료의 열수력 설계시에 적용하고 있는 부수고 내의 모든 열수력학적 변수가 일정하다고 가정하는 부수로 해석방법은 봉다발내의 실제 열전달 현상과는 상당한 차이가 있음을 보여주었다.

• 한국태양에너지학회:학술대회논문집
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• 2011.11a
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• pp.74-79
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• 2011

Concentration characteristics of the KIER solar furnace are analyzed with a heat flux measurement technique. Total heat capacity of 40kW was confirmed within 1.04% average error, and the normalized maximum heat flux of 3,452 $kW/m^2$ was proved. Non-Gaussian flux distribution in the vertical direction implies that reflectors should not be random rather inclined downwards. Moreover, we characterized flux distribution variations with furnace blind opening ratio, distance from the focal plane, and misalignment of the measurement system. Based on the results, the heat flux distribution can be simply estimated once reflectivity and direct normal insolation values are known. This study will be helpful to the design and the performance evaluation of receivers or chemical reactors.

• Journal of the Korean Society of Propulsion Engineers
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• v.6 no.4
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• pp.1-6
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• 2002

A numerical heat transfer analysis and the structural analysis were performed for the design of sub-scale combustion chamber's coolant passage. The heat flux through the combustion chamber wall was estimated by 2-D heat transfer analysis of compressible hot gas and the result was applied as a thermal boundary condition of 3-D analysis. The heat flux estimated by the present method agreed well with the experimental correlation and proved to be insensitive to cooling condition. So the same thermal boundary condition was applied for various operating conditions. The maximum temperature of combustion chamber wall was predicted by 3-D analysis for single coolant passage and the result will be used for the development of a regeneratively cooled combustion chamber. Also estimated were the stress distribution and structural safety of coolant passage through the static structural analysis.