• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.941-942
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• 2011

A thermal equivalent circuit of IPMSM considering eddy current loss of PM and core loss of rotor is proposed. This thermal equivalent model is represented by the thermal resistances and thermal capacitances. In order to determine the factor of each parameter, a heating test is processed. Additionally, the eddy current loss of PM is calculated by a transient 3D finite element analysis. Finally, this thermal equivalent model is verified by a temperature test in a 25kW 12-pole/18-slot IPMSM with varying load.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.13 no.7
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• pp.647-652
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• 2001

The thermal comfort of indoor spaces is very important factor in our life. Regions, cultures, climates and individual difference for establishing thermally comfortable environments should be considered carefully because these factors have a large influence on the thermal comfort doing some complicated interactions with environmental, psychological and physical elements. Recently, predicted mean vote(PMV) based on the heat transfer theory between environmental factors and human bodies has evaluated by many researchers and widely used nowadays. The objective of this study is to evaluate the thermal comfort in workspaces with personal air conditioning system using the measurements of environmental comfort parameters and the questionnaire survey of occupant's thermal senses with response to the environment.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.05a
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• pp.249-254
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• 2003

The thermal coefficient of concrete is measured using dilatometer (AASHTO TP60) and strain gage. Testing parameters such as six different coarse aggregate types, cycles of warming and cooling, specimen shape and measurement types were investigated to evaluate the influencing factors for thermal coefficient of concrete. According to experimental results, the thermal coefficient of concrete made with crushed aggregate showed 9.2 -10.$\mu\varepsilon/^{\circ}C$, , however recycled coarse aggregate classified type II showed a little increasing in comparison with crushed aggregate. The thermal coefficient of concrete made with recycled aggregate was reduced 0.2-0.4$\mu\varepsilon/^{\circ}C$, under temperature cycles. However, specimen shapes were revealed as mainly affecting factors on the thermal coefficient of concrete. Finally the thermal coefficient value determined by the dilatometer device was shown to be similar to the value from PML 60.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.13 no.2
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• pp.31-37
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• 2017

The heat transfer function or thermal performance is the most important function of the steam generator component in nuclear power plants. The declining of thermal performance, fouling does not affect the electric power of the nuclear power plant within a certain fouling level, but it affects the output when goes beyond the governor valve wide open of the turbine. The VWO steam pressure can be predicted through the thermal performance evaluation of steam generators in the nuclear power plant. In consideration of the fouling characteristics of the steam generator, methods of the thermal performance evaluation and fouling cases are reviewed, and also the critical VWO value is estimated through the actual thermal performance evaluation. It is necessary to apply the VWO theory based on the thermal performance of the steam generators.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.12 no.2
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• pp.107-113
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• 2013

When the main spindle of high precision machine tools are run many hours, heat is generated in bearing parts of the inside of the spindle. Also, headstock is appeared distortion by inside and outside temperature difference of a machine. This paper studies method to measure behavior of machine tool about these thermal effects. In addition, it estimates measurement uncertainty factors which can be appeared in thermal effects measurement. Finding the factor of thermal affect measurement is important for estimation of measurement uncertainty. This paper measures thermal effects of high precision machine tools and evaluates the important factors of uncertainty.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.59 no.4
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• pp.450-455
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• 2010

The performance modeling of a $25{\mu}m$ pitch VGA ${\mu}$-bolometer with the self-aligned thermal resistor structure is carried out. The self-aligned thermal resistor can be utilized for the maximizing the thermal resistance and the fill factor of a bolometer, so the performance improvement can be expected. From the results of the performance modeling of the micro-bolometer with self-align thermal resistor for a $25{\mu}m$ pitch $640{\times}480$ microbolometer designed with $0.6{\mu}m$ minimum feature size, the drastic improvements of NETD from 38.7 mK to 19.1 mK, responsivity of 1.9 times are expected with a self aligned thermal resistor structure. The main reason for the performance improvements with a self-aligned thermal resistor structure comes from the increasement of the thermal resistance.

• Journal of the Korean Solar Energy Society
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• v.33 no.3
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• pp.51-57
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• 2013

Metal curtain wall systems are widely used in high-rise commercial and residential buildings. While aluminum is the most frequent used frame material, steel framing is also reemerging as a high-performance material in glazed curtain walls due to less thermal conductivity and design flexibility. The purpose of this study is to evaluate thermal performance of a steel frame curtain wall system by comparing with a aluminum frame curtain wall system. The thermal transmittance was measured according to KS 2278, and condensation resistance was calculated by the test results according to KS F 2295. The steel framing test specimen showed lower thermal transmittance and temperature descending factor compared to the aluminum framing test specimen.

• Wind and Structures
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• v.27 no.6
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• pp.369-380
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• 2018

In this research work, nonlinear thermal buckling behavior of functionally graded (FG) plates is explored based a new higher-order shear deformation theory (HSDT). The present model has just four unknowns, by using a new supposition of the displacement field which enforces undetermined integral variables. A shear correction factor is, thus, not necessary. A power law distribution is employed to express the disparity of volume fraction of material distributions. Three kinds of thermal loading, namely, uniform, linear, and nonlinear and temperature rises over z-axis direction are examined. The non-linear governing equations are resolved for plates subjected to simply supported boundary conditions at the edges. The results are approved with those existing in the literature. Impacts of various parameters such as aspect and thickness ratios, gradient index, type of thermal load rising, on the non-dimensional thermal buckling load are all examined.

• Proceedings of the KSME Conference
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• 2005.11a
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• pp.20.2-20.2
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• 2005

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.11
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• pp.2390-2398
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• 2002

For integrity analysis of nuclear reactor pressure vessel, including the Pressurized thermal shock analysis, the fast and accurate calculation of the stress intensity factor at the crack tip is needed. For this, a simple approximation scheme is developed and the resulting stress intensity factors for axial semi-elliptical cracks in cylindrical vessel under various loading conditions are compared with those of the finite element method and other approximation methods, such as Raju-Newman's equation and ASME Sec. Xl approach. For these, three-dimensional finite-element analyses are performed to obtain the stress intensity factors for various surface cracks with t/R = 0.1. The approximation methods, incorporated in VINTIN (Vessel INTegrity analysis-INner flaws), utilizes the influence coefficients to calculate the stress intensity factor at the crack tip. This method has been compared with other solution methods including 3-D finite clement analysis for internal pressure, cooldown, and pressurized thermal shock loading conditions. The approximation solutions are within $\pm$2.5% of the those of FEA using symmetric model of one-forth of a vessel under pressure loading, and 1-3% higher under pressurized thermal shock condition. The analysis results confirm that the VINTIN method provides sufficiently accurate stress intensity factor values for axial semi-elliptical flaws on the surface of the reactor pressure vessel.