• Steel and Composite Structures
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• 제34권6호
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• pp.819-835
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• 2020

The effects of atmospheric thermal loads on the response of structural elements that are exposed to open environments have been recognized by research works and design specifications. The main source of atmospheric heat is solar radiation, which dominates the variation of the temperature of air, earth surface and all exposed objects. The temperature distribution along the depth of steel members may differ with the geometry configuration, which means that the different-configuration steel members may suffer different thermally induced strains and stresses. In this research, an experimental steel beam was instrumented with many thermocouples in addition to other sensors. Surface temperatures, air temperature, solar radiation and wind speed measurements were recorded continuously for 21 summer days. Based on a finite element thermal analysis, which was verified using the experimental records, several parametric studies were directed to investigate the effect of the geometrical parameters of AISC standard steel sections on their thermal response. The results showed that the overall size of the beam, its depth and the thickness of its elements are of significant effect on vertical temperature distributions and temperature differences.

• Journal of Mechanical Science and Technology
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• 제15권3호
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• pp.357-365
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• 2001

The aim of this paper is to perform the experiment and the numerical simulation for investigating the heat transfer in a regenerator system with ceramic honeycomb and to suggest a useful correlation for optimization of the regenerator system. For achieving this, the effects of some parameters were investigated, e. g., switching time, cell size and length of honeycomb on the mean temperature efficiency. The measured temperatures by R-type thermocouples were compared with the predictions by means of the commercial package, STAR-CD. A useful correlation for thermal efficiency was newly proposed as a function of the normalized switching time, defined in terms of switching time, cell size and length of honeycomb. The results showed that the thermal efficiency is above 90% and the normalized heat exchange rate is higher than 80% when the normalized switching time is less than 1000.

• 대한기계학회논문집B
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• 제27권7호
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• pp.877-882
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• 2003

The main objective of the present study is to analyze the heat transfer characteristics in the vacuum carburizing furnace. Local temperatures are measured at different locations in the self-fabricated furnace for various operating conditions using K-type thermocouples. In addition, the present study simulates the fluid flows and heat transfer in the vacuum carburizing furnace using a commercial package (Fluent V. 6.0), and compares the predictions of local temperatures with experimental data. The temperature and flow fields are predicted. It is found that the time taken for reaching the steady-state temperature under the vacuum pressure is shorter than that under the normal pressure condition. It means that the carburizing furnace under vacuum pressure condition is capable of saving the required energy more efficiently than the furnace under the normal pressure condition. Furthermore, the temperature variations predicted by the numerical simulations are in good agreement with experimental data.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 춘계학술대회논문집B
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• pp.240-245
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• 2000

In this study, thickness, density and effective thermal conductivity of frost forming on the horizontal cylinder were measured with various air temperature and humidity. Reynolds number and temperature of cooling surface are controlled 17300 and $-l5^{\circ}C$ respectively. In each case of air temperature $5^{\circ}C,\;10^{\circ}C,\;15^{\circ}C,$ varying absolute humidity, experiments were executed. In measuring frost surface temperature and thickness of frost layer, infrared thermocouples and CCD camera were used. Frost was gathered from cylinder to measure mass of frost layer. Experimental data showed that the thickness and effective thermal conductivity of the frost layer increase with respect to time. Thickness of frost layer increase with humidity increasing, and density of frost layer increase with air temperature rising. Frost growth with air temperature and density of frost layer with humidity are affected by whether dew point is below or above freezing point.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.302-307
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• 2003

Demand of the LCD-TV is remarkably increasing with development of the LCD technology in these days. Thus, this research has analyzed thermal problems such as heat transfer characteristics inside and outside the LCD-TV using numerical simulation and experiments. The simulated results have been compared with the experimental results using an infrared (IR) camera and T-type thermocouples. The optimal design of structure has been proposed to improve the thermal efficiency of radiation from the comparison.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.199-204
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• 2003

In the present study, the compression process in scroll compressor was simulated in consideration of flow leakage and heat transfer. Tangential and radial leakages of the refrigerant between the scrolls were considered as nozzle flow. The experiment was first conducted with a scroll compressor for automobile air conditioning system and R134a as a refrigerant. Temperature and pressure were measured at the suction and discharge ports of the compressor to determine the thermodynamic states of the refrigerant flow. Temperature distribution of the scroll with the involute angle was also measured by thermocouples that were installed inside the scroll. Measured temperature distribution was compared with the numerical results. From this result, the thermal effect of mechanical contact was found to be important in heat transfer of the compression process.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.205-209
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• 2003

The condensation water temperature $(T_{CW})$ distributions on the combi-drum washer of condensation type which the cloth washes, rinses, spins and dry cloth over a heater were measured using the thermocouples. During the drying process, in order to find out the relationship between the $T_{CW}$ distribution and the cloth dryness level $(C_{D1})$, the experiment was made for the dehydration rate of the cloth $(C_{D0})$ is 63%, the weight of cloth $(W_{C0})$ from 1 to 6kg. In result, according to $W_{C0}$ and $C_{D0}$, the distributions of $T_{CW}$ are very different. Using this tendency, it was appropriate and it developed the automatic drying algorithm and it was gotten dryness level regardless of $W_{C0}$, $C_{D0}$ and the other factor.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2016년도 추계 학술논문 발표대회
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• pp.5-6
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• 2016

When concrete exposed to low temperatures, the free water in the concrete is freeze. If the pressure developed exceeds the tensile strength of the concrete, the cavity will dilate and rupture. It cause expansion and cracking, scaling and crumbling of the concrete. In this study, to prevent such damage, five different types of form were used. Concrete was poured into each form, cured for 7 days at temperature of -10℃. To measure the temperature history, two thermocouples were installed on each of the inside and outside. And to measure the compressive strength, collected core from each form. The maturity is formed by temperature history. The maturity and the compressive strength has a correlation.

• 한국정밀공학회지
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• 제34권4호
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• pp.253-258
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• 2017

This paper presents a numerical study on the thermal characteristics of a milling process of titanium alloy with nanofluid minimum-quantity lubrication (MQL). The computational fluid dynamics (CFD) approach is introduced for establishing the numerical model for the nanofluid MQL milling process, and estimated temperatures for pure MQL and for nanofluid MQL using both hexagonal boron nitride (hBN) and nanodiamond particles are compared with the temperatures measured by thermocouples in the titanium alloy workpiece. The estimated workpiece temperatures are similar to experimental ones, and the model is validated.

• Tribology and Lubricants
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• 제11권5호
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• pp.122-127
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• 1995

The heat generations of angular contact ball bearings are studied experimentally with numerical simulations. The temperature variations of inner and outer races and the temperature increase distributions are measured by using thermocouples for the spindle rotational speeds, preloads, viscosity of oils, and lubrication methods. The measured values from experiments are used to estimate the heat generation rates. The heat generation is focused mainly on the dominant sources which are robbings due to spin and gyro-moments of bearing balls, applied load and viscous friction. Oil-jet and oil-air lubrication methods are adopted using oils with different viscosities.