• Transactions of the Korean Society of Mechanical Engineers B
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• v.21 no.2
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• pp.303-315
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• 1997

The theoretical model for the transient probe method is the modified Jaeger model which is used perfect line source theory. The transient probe technique has been developed for the simultaneous determination of thermal conductivity, diffusivity and volumetric heat capacity of liquids. The Levenberg-Marquardt iteration method is adapted to obtain thermal property within nonlinear range. Experimental results of liquids were found to agree well with recommended thermal property data.

• Journal of KSNVE
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• v.4 no.3
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• pp.353-363
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• 1994

The non-preiodic fluctuation of the engine torque appears to be the major source of the torsional vibration of the automotive driveline. The reduction of this torsional vibration hs become a significant problem along with the requirements of higher performance. The shuffle(tip-in, tip-out) is the transient vibration phenomenon of a vehicle which appears at the sudden change of an accelerator under traveling. By executing of an experiment and a simulation using a model, it has become possible to obtain the design parameter of a driveline for the torsional vibration. This paper presents an experimental and theoretical research on the transient vibration phenomenon of a vehicle which appears at the sudden change of an accelerator under traveling. A dynamic model for the automotive driveline was developed, and all parameters of the mmdel were evaluated with experimental data. The results are as follows: (1) The lower the gea ratio of the transmission is, the more the transient vibration phenomenon of a vehicle appears clearly. (2) The transient vibration phenomenon of a vehicle is affected by the design parmeter of the driveline.

• Proceedings of the KIPE Conference
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• 2004.07b
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• pp.686-690
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• 2004

This paper describes the performance improvement of transient response and the modeling of small aircraft onboard generator. As the characteristics of the stator coil which are a major parameters of transient response were improved, the characteristics of transient response could be increased, therefore, the improved generator can be satisfied with large and fast load changes. Established the control model of the generator, it could be possible to do the analysis of generator performance, and improve the operational stability of the generator system using the control model.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.15 no.11
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• pp.991-996
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• 2002

Transient magnetic diffusion process in a melt-cast BSCCO-2212 tube is analyzed by an analytical method. The transient diffusion partial differential equation is transformed into an ordinary differential equation by integral method. The penetration depth of magnetic field into a superconducting tube is obtained by solving the differential equation numerically. The results show that the penetration depth as a function of time which is somewhat different from the results by Bean's critical state model. The reason of the difference between the present results and that of Bean's model is discussed and compared in this paper.

• Proceedings of the Korean Nuclear Society Conference
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• 1996.05b
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• pp.213-218
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• 1996

A simulation model for the transient behavior of CANDU U-tube steam generator(UTSG) has been developed for application to the simulation of operational transient behavior of CANDU nuclear power plant. For application to CANDU UTSG. tile design characteristics of CANDU UTSG such as Wolsong Units, feedwater inlet near the tube sheet. is approximated. For realistic prediction of thermal hydraulic behavior of and tube bundle region is divided into two separate control volumes, subcooled region and saturated region. and the variation of thermal hydraulic properties within a control volume is considered. Test results for typical CANDU operational transient case show reasonable transient behavior of steam generator and considered to be applicable to the simulation of overall plant.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.54 no.10
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• pp.487-495
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• 2005

This paper reviews the characteristic of thermal and temperature of oil field cable in transient state such as grounding fault and lightning surge. For analysis in various conditions, many actual underground power cable systems are modeled using ATP. These results are applied for the examination of temperature increase when the single line to ground fault by the breakdown of insulation part and hitting of lightning surge are occurred. The inner part temperature of OF cable is analysed according to the various kinds of cable using the thermal model of transient state. The temperature increase of sheath and crossbonded lead bv fault current is also analysed using IEC 60949.

• Journal of Biosystems Engineering
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• v.22 no.1
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• pp.59-67
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• 1997

An experimental apparatus was developed for the rapid determination of thermal conductivity by transient probe method. The theoretical basis for transient probe method has been investigated. The mathematical model for this method is the Carslaw and Jaeger model which is used perfect line source theory. The small needle probe which is equipped with thermocouple and heating element is constructed. A software that performs data analysis and acquisition is programmed. The influence of the power dissipated per unit length of the probe has been assessed for glycerin. The result showed no significant correlation between thermal conductivity and power input. Determination made with this experimental apparatus were found to agree well with the recommended thermal conductivity data.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.04a
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• pp.41-45
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• 2002

Transient magnetic diffusion process in a melt-cast BSCCO-2212 tube is analyzed by an analytical method. The transient diffusion equation is transformed into an ordinary differential equation by integral method. The penetration depth of magnetic field into a superconducting tube is obtained by solving the differential equation numerically. The results show that the penetration depth as a function of time which is somewhat different from the results by Bean's critical current model. The reason of the difference between the present results and that of Bean's model is discussed and compared in this paper.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.11 no.1
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• pp.81-90
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• 1999

The performance evaluation technique of a heat exchanger is described by using a transient response analysis for the determination of an average heat transfer coefficient. The model using a finite difference method can accommodate arbitrary inlet fluid temperature as well as longitudinal conduction. Temperature histories are obtained from the experiments at the inlet and outlet of test core. Heat transfer coefficient and friction factor of the plate array are obtained in short times using the data reduction program of transient response analysis in the single-blow method. The results agree very well with theoretical results. It is shown that the rms deviations are very small and the performance evaluation technique gives rapid and accurate results.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.13 no.6
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• pp.514-523
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• 2001

The thermal performance characteristics of gas-loaded heat pipe(GLHP) were investigated by using transient diffuse-front model. Numerical evaluation of the GLHP is made with water as a working fluid and Nitrogen as control gas in the stainless steel tube. The transient vapor temperature and wall temperature were obtained. It is found that the temperature profiles and gas mole fraction distribution have been mainly influence by the diffusion between working fluid and noncondensable control gas in the condenser of GLHP. It is also found that he large power input make the diffusion region smaller.