• Proceedings of the Korea Society for Simulation Conference
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• 2001.10a
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• pp.387-390
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• 2001

Thermopile thermometer can measure the temperature of an object without attaching the object. It measures the temperature by receiving the radiation energy from objects. The idea of this is from the law of Stefan-Boltzmann. In the past it was not used well because the size was big and the cost was too expensive. But, In these days it can be used many field because the size become smaller and advantage of cost by using micro machine technology. However, The accuracy of measuring is not better than electric type. So we want to improve the accuracy of sensor by analyzing the heat transfer of the thermopile. To analyze temperature distribution in the thermopile sensor, we use the FEM software which is named ANSYS. The conduction and radiation heat transfer is considered to simulate the temperature distribution and time response inside of the sensor.

• Progress in Superconductivity and Cryogenics
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• v.5 no.2
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• pp.58-65
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• 2003

The high temperature superconductivity(HTS) cable must be cooled below the nitrogen liquefaction temperature to applicate the cable in power generation and transmi-ssion system under the superconducting state. To obtain superconducting state. a reliable cryocooler system is required. Structural and thermal design have been performed to design cryocooler system operated with reverse Brayton cycle using gas neon as refrigerant. This cryocooler system consists of compressor. recuperator. coldbox. control valves and has 1 kW cooling capacity. Heat loss calculation was conducted for the given cryocooler system by considering the conduction and radiation through the multi-layer insulation(MLI) and high vacuum. The results can be summarized as: conduction heat loss is 7 W in valves and access port and radiation heat loss is 18 W through the surface of cryocooler. The full design specifications were discussed and the results were applied to construct in house HTS cable cooling system.

• Journal of the Korean Society of Industry Convergence
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• v.8 no.2
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• pp.105-112
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• 2005

The characteristics of natural convection heat transfer combined with radiation in a vertical parallel plates has been investigated experimentally. The vertical channel is consisted with a heated wall and three protruding heating sources attached on the opposite wall. The cooling of modules has been experimented with heating the wall as well as modules themselves at different aspects ratios and heating fluxes. As the location of module is higher, the temperature becomes higher, but the increasement is smaller. When the aspect ratio is lower than 26, its effect on the temperature is not significant rather than that of the radiation heat transfer. Furthermore, the correlation of Nusselt number with the Rayleigh number are attempted, but additional treatment is needed to accomodate the cases of heating module and/or opposite wall.

• Journal of Biosystems Engineering
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• v.18 no.1
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• pp.48-59
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• 1993

Pepper is considered as one of main crops not only in the agricultural production but also in farmer's income. Red-pepper is much consumed by Koreans everyday in the form of powder, but its processing processes such as drying and grinding cause many problems. Consequently, it is required to improve the quality of red-pepper powder for high dietary life. This study was conducted to investigate the heat and mass transfer characteristics of red-pepper powder by convection and radiation conditioning. Physical and thermal properties such as specific heat, thermal conductivity and thermal diffusivity were also determined in terms of moisture content of the powder.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.7 no.3
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• pp.461-472
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• 1995

The interaction of laminar mixed convection and surface radiation in a two-dimensional channel with an array of rectangular blocks is analyzed numerically. Three blocks are maintained at high temperature and the other bottom and top horizontal walls are insulated. Discrete ordinate method(DOM) is introduced to analyze the radiative heat transfer. The effects of the variations of Reynolds number and channel specifications on the heat transfer characteristics are investigated. The average Nusselt numbers along the block surfaces are correlated and presented in terms of Reynolds number and dimensionless geometric parameters such as the block spacing, height and channel spacing. For the conditions considered in this study, average Nusselt numbers along the block surfaces are strongly influenced by the channel spacing and Reynolds number but weakly influenced by the block spacing and block height.

• Nuclear Engineering and Technology
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• v.49 no.8
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• pp.1636-1644
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• 2017

The main purpose of this article is to describe the magnetohydrodynamic stagnation point flow of Walter-B nanofluid over a stretching sheet. The phenomena of heat and mass transfer are based on the involvement of thermal radiation and chemical reaction. Characteristics of Newtonian heating are given special attention. The Brownian motion and thermophoresis models are introduced in the temperature and concentration expressions. Appropriate variables are implemented for the transformation of partial differential frameworks into sets of ordinary differential equations. Plots for velocity, temperature, and nanoparticle concentration are displayed and analyzed for governing parameters. The skin friction coefficient and local Nusselt and Sherwood numbers are studied using numerical values. The temperature and heat transfer rate are enhanced within the frame of the thermal conjugate parameter.

• Nuclear Engineering and Technology
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• v.52 no.11
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• pp.2620-2629
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• 2020

As an early stage in the development of a water calorimeter, this study established a computer simulation methodology for analyzing the thermal behavior of a water calorimeter based on radiation transport and energy deposition. As a result, this study developed a method wherein the energy deposition distribution, which is obtained by applying Monte Carlo methods in water calorimeters, is directly used as a heat source for the thermal analysis model. Based on the proposed method, heat transfer in a water vessel and the effect of thermistor self-heating were analyzed. Through an analysis of the water velocities with and without a water vessel, it was found that a water vessel can serve as a convection barrier. Furthermore, it was confirmed that when considering thermistor self-heating, the water temperature change at the thermistor location is 0.219 mK higher compared to that when the thermistor was not considered. Therefore, thermistor self-heating must be considered to analyze the thermal behavior of a water calorimeter more accurately.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2003.10a
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• pp.176-180
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• 2003

To obtain superconducting state, a reliable cryocooler system is required. Structural and thermal design have been performed to design cryocooler system operated with reverse Brayton cycle using gas neon as refrigerant. This cryocooler system consists of compressor recuperator, coldbox, control valves and has 1 ㎾ cooling capacity. Heat loss calculation was conducted for the given cryocooler system by considering the conduction and radiation through the multi-layer insulation (MLI) and high vacuum. The results can be summarized as; conduction heat loss is 7 W in valves and access port and radiation heat loss is 18 W through the surface of cryocooler. The full design specifications were discussed.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.30 no.3 s.246
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• pp.201-207
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• 2006

Transient radiative heat transfer is analyzed in a one-dimensional slab using finite volume method (FVM). In this study, the step, $2^{nd}$ order upwind, and QUICK schemes are used for incident diffuse radiation and collimated beam, respectively. The results fer diffuse radiation show that all schemes applied in this study give good agreements with available published results. In case of collimated beam however, the results show deviations from the analytical solutions. To successfully describe the propagations of collimated beam shock capturing schemes such as TVD scheme are need to be developed.

• Nuclear Engineering and Technology
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• v.54 no.11
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• pp.4348-4358
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• 2022

The thermal-hydraulics phenomena in a containment during an accident will necessarily include radiative heat transfer (i) within the gas mixture due to the high radiative absorption and emission of steam and (ii) between the gas mixture and the surrounding structures. The analysis of some previous PANDA experiments (PSI, Switzerland) demonstrated the importance of the proper modelling of radiation for the benefit of numerical simulations. These results together with dedicated scoping calculations conducted for the present experiments indicated that the radiative heat transfer is considerable, even for a very low amount of steam (≈2%). The H2P2 series conducted in the large-scale PANDA facility at the Paul-Scherrer-Institut (PSI) in the framework of the OECD/NEA HYMERES-2 project is intended to enhance the understanding of thermal radiation phenomena and to provide a benchmark for corresponding numerical simulations. Thus, the test matrix was tailored around the two opposite extremes: either gas compositions with small steam content such that radiative heat transfer phenomena can be neglected. Or gas mixtures containing larger amounts of steam, so that radiative heat transfer is expected to play a dominant role. The H2P2 series consists of 5 experiments designed to isolate the radiation phenomena from convective and diffusive effects as much as possible. One vessel with a diameter of 4 m and a height of 8 m was preconditioned with different mixtures of air / steam at room and elevated temperatures. This was followed by the build-up of a stable helium stratification at constant pressure in the upper part of the vessel. After that, helium was injected from the top into the vessel which leads to an increase of the vessel pressure and a corresponding elevation-dependent and transient rise of the gas temperature. It is shown that even the addition of small amounts of steam in the initial gas atmosphere considerably impacts the radiative heat transport throughout all phases of the experiments and markedly influences i) the monitored gas peak temperature, ii) the temperature history during the compression and iii) the following relaxation phase after the compression was stopped. These PANDA experiments are the first of its kind conducted in a large scale thermal-hydraulic facility.