• Journal of the Korean Institute of Gas
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• v.23 no.4
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• pp.74-79
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• 2019

Specially designed test material was used for workpiece temperature measurement in the commercial reheating furnace and a linearized thermal model was applied for real time temperature prediction. The applied furnace is a walking beam type and specification of the workpiece is a STS302 which is 160mm in width, 160mm in height and 8100mm in length. Also six thermocouples were installed in width, height and length direction for temperature measurement. Ambient temperature in the furnace was raised to 1265 Celsius degrees and it took about 2.5 hours from loading to discharging of the workpiece. As a result of the experiment, temperature of the workpiece at discharge was 1257 Celsius degrees on the average in the range of 1256 to 1259 Celsius degrees, and predicted average temperature through the thermal model was 1251 Celsius degrees. Therefore, the deviation of the analysis and test results is about 6 degrees, which is within the range of 10 degrees required by the industry.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.485-488
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• 2008

Fire intensity in tunnel fire is very severe, which might cause the spalling on the surface of shotcrete and concrete lining exposed to the heat as well as rapidly-reducing stress due to heat transfer by steel material such as anchor embedded in tunnel which plays the critical role in securing the stability of the tunnel. In this study, a fire test to identity the heat intensity(Modifired Hydrocarbon Curve) and the fire resistance of steel materials embedded as parameters, was carried out. And the evaluation to identify the thermal damage, which was based on critical temperature range for thermal damage of steel materials determined according to the road tunnel fire resistance standard established by ITA(International Tunneling Association).

• Journal of the Korean Society of Propulsion Engineers
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• v.10 no.3
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• pp.53-59
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• 2006

This paper presents the IR-Lamp test results of evaluating heat protection performance and measuring of mechanical/thermal properties in the heat protection material of missile external surface. The results showed that increasing the contents of microballoons improved the heat protection performance, but the mechanical properties were deteriorated. Among the kinds of microballoons, Epoxy/Phenolic Microballoons mixture showed the best mechanical properties and low thermal conductivity. Epoxy/Cork mixture showed the best heat protection in the IR-Lamp test, though it has low mechanical properties and high thermal conductivity.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.17 no.8
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• pp.695-703
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• 2005

The objective of this study is to determine the effective thermal conductivity and thermal resistance values in test boreholes with three different fill materials. To evaluate these heat transfer properties, in-situ tests on four vertical boreholes were conducted by adding a monitored amount of heat to water over various test lengths. Two parameter estimation models, line-source and numerical one-dimensional models, for evaluation of thermal response test data were compared when applied on the same four data sets. Results show that the average thermal conductivity deviation between measured data and these two models is in the range of $3.03\%$ to $4.45\%$. The effect of increasing grout thermal conductivity from 1.34 to 1.82 $W/m^{\circ}C$ resulted in overall increases in effective formation thermal conductivity by $11.1\%$ to $51.9\%$ and reductions in borehole thermal resistance by $11.6\%$ to $26.1\%$.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.8 no.4
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• pp.8-16
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• 2012

The use of energy pile foundation has been increased for economic utilization of geothermal energy. This paper describes an experimental and numerical study on thermal response tests (TRTs) using W and 3U-shaped ground heat exchangers (GHEs) in precast-high strength concrete (PHC) energy piles. Ground thermal conductivity and borehole thermal resistance were measured and compared with those numerical analysis. W-shpaed GHE showed higher heat transfer behavior than 3U-shaped one because of different conditions such as pile size and volume of grout. That is, ground thermal conductivity using W-shaped GHE was higher than that of 3U shaped GHE, and borehole thermal resistance vice versa. The relative error of borehole resistance values between numerical and analytical solution was less than 5%.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.7 no.2
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• pp.43-50
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• 2011

This paper presents how to analyze heat transfer characteristics of double-layered soils. Thermal response tests were conducted to measure the ground thermal conductivities of Joomunjin sand and double layered soils filled in a steel box of which the size is $5m{\times}1m{\times}1m$. Double-layered soils were composed of Joomunjin sand and Kaoline clay. Each thermal conductivity of Joomunjin sand and Kaloine clay was measured by using Heat Flow Meter considering different void ratio. The ground thermal conductivity of double-layered soils was 15% smaller than that of Joomunjin sand.

• Composites Research
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• v.33 no.5
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• pp.302-308
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• 2020

We measured the thermal conductivity of composite materials manufactured by the autoclave and vacuum bag only processes and predicted the cure behavior of the external and internal of composite parts with a cure kinetics model. The temperature difference between the external and internal depends on the processes because of the change of thermal conductivity. In the autoclave process, the temperature and cure behavior of the internal were similar to those of the external because of the high thermal conductivity. However, the temperature of the internal of the vacuum bag only process was different from that of the external. The difference can influence the part quality and evacuation of air. Compression tests were performed to find the mechanical property using 0° unidirectional specimens. The composite of the vacuum bag only process was found to have a lower compressive strength than that of the autoclave process.

• International Journal of Highway Engineering
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• v.13 no.1
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• pp.87-96
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• 2011

According to adverse effects of ecosystems due to a bulk of fossil fuel consumption, utilization of sustainable and renewable energy is required. In this paper, converting the energy crisis into an opportunity of new growth is expected by converting heat energy in asphalt pavement into electric power using thermoelectric effect. For this, experiments of inserting heat collector pipe and thermoelectric element into asphalt were performed, and the electric power of heat energy harvesting was measured for development of efficient harvesting system of heat energy. As the results of experiments, electric conversion of average 19.86W per day is possible at $1m^2$ conversion area at a depth of 5cm, and possibility of this system was confirmed. Consequently, a systematic "Green Road" using sustainable heat energy source in asphalt pavement simultaneously with environmental maintenance and econovic growth was suggested.

• Journal of the Korea Society of Computer and Information
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• v.17 no.12
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• pp.41-47
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• 2012

Every object over $O^{\circ}K$ emits radiant energy based on its own temperature. Uncooled thermal imaging system displays the detected incident radiant energy as an image by signal processing. Recently, the uncooled thermal imaging system is applied to various areas such as medical, industrial, and military applications. Also, several researches are in progress to find new applications of the uncooled thermal imaging system. In this paper, we present effective method for controlling TEC-less detector in the uncooled thermal imaging system and also present the efficient control scheme for maximizing the accuracy of temperature measurement. The proposed scheme is to apply TEC-less and temperature detection algorithm in Uncooled thermal imaging system. In results of tests performed by using the actual chamber, we acquired images of better quality than the former system and temperature measurement accuracy was improved to less than $1^{\circ}C$.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 1999.04a
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• pp.44-44
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• 1999

전적으로 해외기술에 의존하고 있는 소프트 닙 캘린더 피복의 국산화를 위해 시험 제작 된 소프트 닙 캘린더용 연질롤의 캘린더링 효과를 구명하기 위해서 공정 변수에 따른 신문 용지의 물성변화를 평가하였다. 연질 롤로는 (주)광성고무롤에서 시험제작된 경도 90 Shore D의 것을 사용하였으며, 캘린 더링 시의 압력, 가열 롤의 표면온도, 닙 체류 시간, 유입지의 함수율 변화에 따른 신문용지 의 별크, 평활도, 광택도, 인장강도, 인열강도, 불투명도 변화를 조사하였다. 별크는 캘린더링 시 압력, 가열 롤의 표면온도, 닙 체류시간의 증가에 따라 감소하였다. 가열 롤의 표면온도가 높을수록 별크가 크게 감소되었으며, 닙 체류시간이 짧은 경우에는 1 120 226;C 이하에서 캘린더링을 실시하는 것이 별크 유지에 효과적이었다. 평활도는 가열 롤의 표연 온도, 닙 체류시간이 증가함에 따라 개선되었으며, 선압과 함 수율 증가에 의해서도 상승되는 경향을 보였. 인장강도는 유입지의 함수율, 닙 체류시간, 가열 롤의 표면온도가 모두 상승할 경우 증 가하는 결과를 나타내었다. 이는 함수율 증가에 의해 섬유의 유연성이 향상된 상태에서는 칼렌더링 온도와 닙체류 시간 증가에 의한 섬유의 기계적 변형과 열전달에 의한 섬유의 열 변형이 효과적으로 발생하여 섬유간 결합면적이 증가된 결과로 생각되었다. 인열강도는 소프트닙 캘린더링 후 전반적으로 감소하였으나 캘린더링 온도와 닙체류시 간은 인열강도에 미치는 영향은 적은 것으로 나타났다. 소프트 닙 캘린더링 시 발생하는 인 열강도의 저하를 막기 위해서는 닙 체류시간을 짧게 적용하고 섬유의 열변형이 종이의 표변 에서만 일어날 수 있도록 유입지 함수율과 가열롤의 표면온도를 적절히 조절하는 것이 필요 하리라 판단되었다.광택도는 온도와 압력이 증가할수록 증가하였으나, 닙 체류시간에 따라서는 큰 변화를 나타내지 않았으며 120도씨에서는 닙 체류시간의 증가에 따라 광택도가 오히려 감소하기도 하였다. 불투명도는 벌크와 마찬가지로 압력이 높고 가열롤의 표면온도가 높은 경우 낮게 나타 났다 특히 닙 체류시간의 증가에 따라 감소하는 경향을 보였다.보였다.