• 설비공학논문집
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• 제18권6호
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• pp.526-533
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• 2006

The prediction of heat-up time of an LCD glass plate in LCD glass pre-treatment process has been implemented in the present study. Firstly, the analytical solution for one-dimensional radiation heat transfer from IR heaters to a LCD glass plate is obtained. When the surface temperature of the IR heaters is set at 473 K, the heat-up time of LCD glass to averaged temperature of 383K is 28 seconds. In addition, a three dimensional full CFD analysis using STAR-CD is implemented in an effort to consider the effect of 3-D heat loss through the furnace walls. From the results of the 3-D CFB analysis, the heat-up time increases up to 32.5 seconds under the same conditions. When the IR heater temperature in creases up to 573 K, the heat-up time decreases to 12 seconds for the one-dimensional analytical solution and to 13.5 seconds for the 3-D CFD analysis, respectively.

• Journal of Welding and Joining
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• 제19권5호
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• pp.492-498
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• 2001

In the previous study, temperature monitoring of case about shrinkage fit process was performed and heat transfer model was developed in detail by feedback and tuning among monitoring result, process investigation, and analysis result. The gap element in contact between case and core was effectively used in analysis model. In present study, following things are performed to solve deformation of case due to shrinkage fit process on the basis of previous result. Above all, mechanical material properties of case are measured by case specimen for deformation analysis considering weldment of case. Deformation of case before and after shrinkage fit process is measured, too. Three dimensional deformation model is developed by the comparison and inspection between these experimental data and analysis results. Deformation analysis is simulated with the result of heat transfer analysis, in other words, non-coupled analysis is used. Finally the countermeasure for deformation is brought up through those.

• 한국자동차공학회논문집
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• 제9권2호
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• pp.92-98
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• 2001

We determined the transfer coefficient through the analysis of three dimensional temperature distribution in comparison with the measured temperature on the piston in the turbocharged diesel engine. And we analyzed the thermal stress and the thermal deformation with that heat transfer coefficient by using finite element method. According to this results, we found that maximum tempetature range of the piston appeared at the upper part of the piston crown and that the heat transfer coefficient of the upper part of the piston is smaller than that of the lower one. It showed that the maximum thermal deformation is shown at the edge of the upper part of piston and that the maximum thermal stress was shown on the lower part of the piston crown. Finally, we defined the method of determination of a piston heat transfer analysis by using measured temperature on the piston and analyzed temperature with finite element method.

• 한국항공우주학회지
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• 제30권8호
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• pp.112-119
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• 2002

주기적으로 배열된 액체 로켓엔진의 연료 분사기 배열에 대한 3차원 열전달 수치해석을 수행하였다. 해석에는 SIMPLE 알고리즘을 사용한 유한체적법이 적용되었으며 2차원 후향 계단에 대해서 기존의 문헌과 일치하는 열전달 결과를 주었다. 분사기 요소 사이의 거리가 가까울수록 누셀 수와 압력강하가 증가하였다. 레이놀즈 수가 증가할 경우, 누셀 수는 증가 하였으며 무차원 압력강하는 약간 감소하였다.

• International Journal of Fluid Machinery and Systems
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• 제9권3호
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• pp.229-236
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• 2016

Exergetic analysis was introduced in optimization of a rotating equilateral triangular internal cooling channel with staggered square ribs to maximize the net exergy gain. The objective function was defined as the net exergy gain considering the exergy gain by heat transfer and exergy losses by friction and heat transfer process. The flow field and heat transfer in the channel were analysed using three-dimensional Reynolds-averaged Navier-Stokes equations under the uniform temperature condition. Shear stress transport turbulence model has been selected as a turbulence closure through the turbulence model test. Computational results for the area-averaged Nusselt number were validated compared to the experimental data. Three design variables, i.e., the angle of rib, the rib pitch-to-hydraulic diameter ratio and the rib width-to-hydraulic diameter ratio, were selected for the optimization. The optimization was performed at Reynolds number, 20,000. Twenty-two design points were selected by Latin hypercube sampling, and the values of the objective function were evaluated by the RANS analysis at these points. Through optimization, the objective function value was improved by 22.6% compared to that of the reference geometry. Effects of the Reynolds number, rotation number, and buoyancy parameter on the heat transfer performance of the optimum design were also discussed.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1998년도 춘계학술대회논문집
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• pp.231-234
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• 1998

This study presents steady-state finite element analysis of three-dimensional hot extrusion of sections through square dies. The objective of this study is to develop a steady-state finite element method for hot extrusion through square dies, and to provide theoretical basis for the optimal die design and process control in the extrusion technology. In the present work, steady-state assumption is applied to both analyses of deformation and temperature. The analysis of temperature distribution includes heat transfer. Convection like element is adopted for the heat transfer analysis between billet and container, and also billet and die. Distributions of temperature, effective strain rate, velocity and mean stress are discussed to design extrusion die effectively.

• 설비공학논문집
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• 제6권4호
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• pp.337-343
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• 1994

Numerical analysis was applied to a simplified two-dimensional Ondol heating model which consists of heating space on the top of it along with radiant and convective heating floor panel, flue channel in the midway and rectangular underground soil region at the bottom. These three components constitute a system thermally coupled at the top and bottom interfaces of the flue channel. Investigated in the present paper are effects with variations of the Reynolds numbers of 100, 200, and 300, Grashof numbers of $0.1{\times}10^6$ and $0.3{\times}10^6$ and aspect ratios of 15 and 20 on the heat transfer and fluid flow characteristics of two-dimensional Ondol heating model by computer simulation.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.157-162
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• 2003

This study is analysis on the heat transfer of exhaust gas into the muffler at passenger Car. Numerical analysis with Computational fluid Dynamics(CFD) was carried out to investigate exhaust gas flow. The STAR-CD S/W used for the three dimensional steady state CFD analysis in a muffler. The Navier-Stokes Equation is solved with the SIMPLE method in a general cartesian coordinates system. Result of numerical simulation; Inlet and outlet temperature shown about ${\Delta}T=239K$, 216K, 202K at in the muffler. Heat transfer was progressed quickly by atmospheric temperature of muffler external at in the near wall.

• 한국정밀공학회지
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• 제15권11호
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• pp.227-232
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• 1998

The purpose of this study is to develop a numerical method for analyzing the transient heat transfer and evaluating the residual stress. The analysis of heat transfer and thermal stress are carried out by three-dimensional finite element method. Thermal spraying is one of the most common surface coating techniques to be used for many applications. In order to improve the mechanical properties of flame-sprayed ceramic coating layer, the accurate and effective analysis of heat transfer and thermal stress is essentially required.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회B
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• pp.2131-2136
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• 2008

The characteristics of heat transfer and pressure drop in an offset strip fin heat exchanger was studied with a steady-state three dimensional numerical model. Flow Reynolds number $Re_{dh}$ ranged from 10 to 3500 and Prandtl number Pr ranged from 0.7 to 50. The dimensionless performance factors, i.e. 'the pumping power factor F' and 'the heat transfer performance factor J' were analyzed and obtained a relationship between them. Finally, the prediction of F and J factors was generalized for different Prandtl numbers.