• Proceedings of the KIEE Conference
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• 2001.04a
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• pp.84-86
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• 2001

This paper deals with the characteristic and thermal analysis of brushless motors for Rack assist type Electric Power Steering(REPS). The performance of permanent magnet is under the influence of temperature. To predict the motor performance, the thermal analysis is necessary. The equivalent thermal network is composed of the thermal resistance and the temperature of major parts is calculated according to the operating condition.

• Transactions of the Korean hydrogen and new energy society
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• v.26 no.4
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• pp.377-385
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• 2015

This paper presents a thermodynamic performance analysis of regenerative organic Rankine cycle (ORC) using turbine bleeding to utilize low-grade finite thermal energy. Refrigerant R245fa was selected as the working fluid. Special attention is paid to the effects of the turbine bleeding pressure and the turbine bleed fraction on the thermodynamic performance of the system such as net power production and thermal efficiency. Results show that the thermal efficiency has an optimum value with respect to the turbine bleeding pressure and the net power production is lower than the basic ORC while the thermal efficiency is higher.

• 한국태양에너지학회:학술대회논문집
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• 2012.03a
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• pp.445-450
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• 2012

BIPV/T (Building Intergrated PhotoVoltaic/Thermal) is combined system produces electricity and thermal energy. The heat from PV modules should be removed for better electrical performance, and can be converted into useful thermal energy. The efficiency of the PV system's performance will raise by the system removes heat from the PV. The test system is installed to top floor of the experimental house in the KEPCO Research Institute. The planned experiment is following. (1) Supplying heat energy to top floor. (2) Supplying heat and cool energy to thermal storage in the bottom of the top floor. (3) Supplying heat energy to EHP for improved performance. The experimental performance is executed from 13th February to 13th March, 2012. The solar generation of electricity is 4.04kWh under the horizontal solar radiation is $1000W/m^2$ and the air temperature is $25^{\circ}C$.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.8 no.4
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• pp.497-509
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• 1996

Evacuated powder insulations have long been known to have better thermal performance than existing commercially available insulators, such as fiber glass and CFC-blown foam. To make a composite powder panel, a series of individually evacuated panels was encapsulated in a rigid closed cell foam matrix. The panels were encapsulated in a thin glass sheet barrier to preserve the vacuum. The thermal conductivity of the individual panel was found to be $0.0062W/m^{\circ}K$ by experiment and the polyurethane foam above had a thermal conductivity of $0.024W/m^{\circ}K$. In this study, numerical analysis using finite element method was carried out to investigate insulation performance of rigid foam/evacuated powder composite panel with respect to panel geometries such as panel pitch, panel aspect ratio and panel area ratio. Numerical analysis has indicated that more optimal vacuum panel geometries, much lower overall thermal conductivities can be achieved.

• Journal of Advanced Marine Engineering and Technology
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• v.28 no.4
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• pp.648-656
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• 2004

In this study, a highly efficient shell-and-tube heat exchanger with plate fins is considered to improve thermal performance of the conventional shell-and-tube heat exchanger. This type of shell-and-tube heat exchanger with plate fins of various shape is simulated three-dimensionally using a commercial thermal-fluid analysis code. CFX4.4. The effect of the shape of the plate fin on heat transfer characteristics is also investigated by the simulation. Plate fins of four different shapes. plane, plane-slit. wave. and wave-slit fins, are considered. The flow fields, pressure drop and heat transfer characteristics in the heat exchanger are calculated. It is proved that the shell-and-tube heat exchanger with plate fins is superior to the conventional shell-and-tube heat exchanger without plate fins in terms of heat transfer. The shape of the plate fin is important in the performance of a heat exchanger such as heat transfer and pressure drop.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.615-620
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• 2010

During braking of railway vehicles the repetitive thermal shock leads to thermal cracks on disc surface, and the lifetime of brake disc is dependent on the number of trimming works for removing these thermal cracks. Many tries for development of high heat resistant brake disc to extend the disc life and to warrant reliable braking performance has been continued. In present study, we carry out the computational fatigue analysis for thermal fatigue test in three candidate materials which were made to develop new high heat resistant material. Using FEM, we simulate thermal fatigue test in three candidate materials and conventional disc material. We then estimate the number of cycle to thermal crack initiation based on data from mechanical fatigue tests, and the results are compared with each material. For each material, the correction factor for $N_{f-40}$ which is the number of cycles when crack over $40{\mu}m$ was observed in thermal fatigue test is decided. From this study, we can verify the performance of thermal fatigue test system and suggest a qualitatively comparative method for heat resistance by FEM analysis of thermal shocking phenomenon.

• Nuclear Engineering and Technology
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• v.55 no.12
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• pp.4518-4526
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• 2023

NECP-SARAX is a neutronics analysis code system for advanced reactor developed by Nuclear Engineering Computational Physics Laboratory of Xi'an Jiaotong University. In past few years, improvements have been implemented in TULIP code which is the cross-section generation module of NECP-SARAX, including the treatment of resonance interface, considering the self-shielding effect in non-resonance energy range, hyperfine group method and nuclear library with thermal scattering law. Previous studies show that NECP-SARAX has high performance in both fast and thermal spectrum system analysis. The accuracy of TULIP code in fast and thermal spectrum system analysis is demonstrated preliminarily. However, a systematic verification and validation is still necessary. In order to validate the applicability of TULIP code for full energy range, 147 fast spectrum critical experiment benchmarks and 170 thermal spectrum critical experiment benchmarks were selected from ICSBEP and used for analysis. The keff bias between TULIP code and reference value is less than 300 pcm for all fast spectrum benchmarks. And that bias keeps within 200 pcm for thermal spectrum benchmarks with neutron-moderating materials such as polyethylene, beryllium oxide, etc. The numerical results indicate that TULIP code has good performance for the analysis of fast and thermal spectrum system.

• Journal of the Korea institute for structural maintenance and inspection
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• v.17 no.4
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• pp.91-100
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• 2013

This research is to measure and analyze the thermal performance of the apartment structure and to evaluate and establish standards of thermal insulation defect in order to make the basic data necessary for determining the degree of the thermal performance degradation and for repairing and reinforcing the exterior wall of the existing apartment. Furthermore, it is to predict the part of occurrence of the thermal bridge and condensation at the apartment building structure. On the other one hand, it is also to analyze the degree of thermal insulation performance according to the standards of thermal insulation and elapsed time, through the analysis by the workability of concrete.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.4
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• pp.180-184
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• 2012

3-way ball valves have been mostly used for high temperature/high pressure valves using in petrochemical carriers and oil tankers, which requires high quality products with confidentiality and durability. As a larger disaster may be generated by leakage of oil or gas from valves, thus the present research applied a numerical analysis method with thermal-structural coupled field analysis and the performance test. The Max stress by parts was confirmed through thermal-structural coupled field analysis and develop the 3-way ball valve design, which is safe on operating condition. And its performance was verified by carrying out pressure test, leakage test and durability test for the manufactured 3-way ball valves with satisfying it's regulations.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.24 no.1
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• pp.51-60
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• 2012

Optimization procedures of performance analysis for ORC(Organic Rankine Cycle) system are established to the characteristics of low temperature heat sources such as open-type and closed-type. Effective heat recovery and heat extraction related to maximum power of the cycle as well as heat quality and thermal efficiency must be considered in the case of the open-type low temperature heat source. On the other hand, in the case of the closed-type low temperature heat source, only thermal efficiency is important due to constant heat input. In this study, thermal efficiency and exergy efficiency representing a level of close to Carnot cycle are studied, as useful index for the optimization of the ORC system. To validate the results of cycle analysis, those are compared with appropriate experimental data of ORC system as a thermal efficiency point of view.