• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.13 no.7
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• pp.588-594
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• 2001

The purpose of this study is to investigate the thermal and hydrodynamic characteristics of the channel in corrugated plate type heat exchangers numerically. Numerical work has been conducted using the Reynolds Stress Model(RSM) by utilizing the commercial finite-volume code, FLUENT. Based on this model, the dependence of heat transfer and friction factor on geometrical parameters have been investigated. It is found that larger corrugation angle give higher values of heat transfer coefficients and friction factors. As the reynolds number increases, the heat transfer coefficient also increases. It is also observed that the heat transfer coefficient reaches maximum while the friction factor stays relatively low at same corrugation angle. Through the analysis, it is found that the optimum corrugation angle for the heat exchanger performance exists. It is noted that the flow repulsions at the contact point of the two fluid streams make the low mixing more active for larger corrugation angle and high reynolds number.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.6 no.3
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• pp.282-290
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• 1994

A numerical model for the analysis and design of orifice pulse tube refrigerators has been developed. Heat transfer coefficient and friction factors in the model vary with time, and the real physical properties such as thermal conductivity and viscosity were used to improve the accuracy of the model. Thermodynamic behavior of the working fluid within pulse tube refrigerators was investigated and the effect of design parameters, such as reservoir volume, orifice diameter, and NTU of regenerator, on the cooling load and COP was shown.

• Proceedings of the SAREK Conference
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• 2009.06a
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• pp.1135-1140
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• 2009

The present study has been studied on a thermal and flow characteristic of the microchannel waterblock with pass variations in 8 samples. Results of a numerical analysis using the CFX-11 were compared with results of an experiment. Numerical analysis and experiment were conducted under an input power of 150 W, inlet temperature of $35^{\circ}C$ and mass flow rates of $0.7{\sim}2.0\;kg/min$. The numerical results showed reasonably good agreement with the experimental results within about $3{\sim}5%$. Also, the numerical results showed that the sample 2 types with the 2 pass gave better performance than the sample 1 types with the 1 pass from the viewpoints of heat transfer and pressure drop.

• Journal of Advanced Marine Engineering and Technology
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• v.24 no.5
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• pp.33-41
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• 2000

Three dimensional flow fields around passenger car body was computed by PAM-FLOW, well-known and validated computer program for thermal and fluid analysis. Regarding the computational method, a Navier-Stokes solver based on finite element method with various turbulent models and adaptive grid technique (H-refinement)was adopted. The results were physically reasonable and compared with experimental data, giving good agreement. It was found that three dimensional flow simulation with H-refinement technique had potential for prediction of low fie이 around vehicle and the ability to predict vortex in the wake, which is vital for CFD to be used for automobile aerodynamic calculation.

• Proceedings of the KSME Conference
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• 2000.04b
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• pp.956-961
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• 2000

This paper describes the design of a small size Alkali Metal Thermal to Electric Converter (AMTEC) which employs a capillary structure for recirculating sodium working fluid. The cycle is based on the simple and small capillary type ${\beta}"$ -alumina and wick tube element. The proposed cell consists of the 37 conversion elements with capillary tube of $50{\mu}m$ in diameter and the sealed cylindrical vessel of 22mm in outer diameter. Results on the cycle analysis of sodium flow and heat transfer in the cell showed that the expected power output was 4.65W and the conversion efficiency was 19% for the source temperature of 900K.

• Transactions of the Korean Society of Automotive Engineers
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• v.4 no.3
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• pp.187-198
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• 1996

In this study, the performance of an automobile heat storage system using PCM is numerically simulated. For the analysis of system performance. The phase-change of the PCM and the transient forced convective heat transfer for the HTF are considered simultaneously as a conjugate problem. The phase-change behavior is effectively analyzed using a concept of thermal resistance. From the correlations of phase change rate and heat transfer due to the variations of flow rate of HTF around PCM, the automobile heat storage system performance is predicted. The present results amy be used as the fundamental information for the design of automobile heat storage system.

• Journal of the Semiconductor & Display Technology
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• v.11 no.4
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• pp.31-36
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• 2012

The high thrust of the linear motor in the exposer generates the high temperature heat by the friction and the electromagnetic forces on its coil. It can cause the thermal deformation and the accuracy of the equipment is finally decreased which has a bad effect on the productivity. In this research, the heat and flow on the linear motor of the exposer has been analyzed. The existing equipment is non-contact fluid refrigerant type. The numerical analysis data of the existing equipment have been acquired and the reliability of the data has been verified. The revised modeling for the next-generation is suggested for cooling the exposer effectively.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.05b
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• pp.21-24
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• 2005

A computational analysis of hygro-thermal and mechanical behaviour of concrete column at high temperature is presented. The objective of this study is to develop a finite difference model that simulates coupled heat and transport phenomena in reinforced concrete structures exposed to rapid heating conditions such as fires. The theoretical basis for the integrated finite difference method is presented to describe a powerful numerical technique for solving of fluid flow in porous media. The numerical results predict the phenomena of 'moisture clog' and the explosive spalling of concrete under fire. The investigations show that high-strength concrete(HSC) and normal-strength concrete(NSC) exposed to high temperature have different pore pressure buildup dependent on porosity, permeability and moisture contents. HSC has more possibility than NSC on spalling.

• Proceedings of the KSME Conference
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• 2008.11b
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• pp.2298-2303
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• 2008

The increasing demands for the recently released CPU which has had higher heat density, the confined space of desktop PCs, and so on are the main drive for continuously improving PC cooling systems. In order to meet number of demands, this paper describes the flow and thermal behavior of the heat sink combined with heat pipes, and a fan through the numerical analysis by using the computational fluid dynamics(CFD) code and discusses how to extend the cooling capability.

• Proceedings of the SAREK Conference
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• 2007.11a
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• pp.623-628
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• 2007

The purpose of this paper is to study the influence of geometry parameter on the ejector performance. The CFD results were verified with available experimental data. Flow field analysis was also carried out in this study. Variation on the geometry parameter was made by varying the angle of converging duct those are $0.5^{\circ}$, $2.0^{\circ}$ and $3.5^{\circ}$. The converging duct with an angle of $0.5^{\circ}$ gives the highest value of entrainment ratio that is 0.941. Furthermore, from this study it can be concluded that the entrainment ratio decreases with respect to the increase of angle of convergence duct.