• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.1011-1015
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• 2017

In this study, numerical and experimental studies on the nozzle flow in a sub-scale cold flow test were conducted to simulate high altitude condition. In the theoretical calculation, the temperature of the nozzle outlet is calculated to be lower than the liquefaction point, and the fluid exists at the phase change point. Also, numerical analysis result is higher than theory calculation but lower than liquefaction temperature. As a result of cold flow test, it was confirmed that the temperature was much higher than theory and analysis. This is because it assumed that it is adiabatic in the theoretical calculation, but the experiment in the actual environment is not the adiabatic but the heat exchange with the outside exists.

• Journal of the Korean GEO-environmental Society
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• v.15 no.10
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• pp.5-13
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• 2014

In this research, in order to study insulation effect of commercial XPS and recycled PE aggregates for prevention of frost heave in the roadbed of railroad track from the freezing temperature, model tests were carried out in the large freezing room. For this, thermal conductivities were measured for various dry densities, water contents, temperatures and mixing ratios of PE aggregates. From the tests, it can be seen that thermal conductivities of roadbed decrease with the increase of the ratio of mixed PE aggregates. However it was sensitive to the changes of temperature and water content due to the amount of water in the voids. From the model test of railroad track, it can be seen that the time to reach $0^{\circ}C$ was longer for XPS than that for the PE aggregates. Also the test shows best insulation effect can be achieved when XPS board was installed above the PE aggregate layer rather than the opposite order.

• Journal of the Korean Geotechnical Society
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• v.33 no.8
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• pp.17-27
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• 2017

Gangwon province which is located in northeast of Korea is the coldest region where average daily temperature is below zero during winter while the other regions are above zero. However, there have been insufficient researches on the insulation design and the effect of the insulation on the freezing damages, even though freezing damages were reported consistently in the lining of road tunnel during winter. In this study, to investigate the effect of insulations on the reduction of freezing damages, numerical analysis was performed considering geotechnical and meteorological characteristics in Gangwon province during winter. As a result, it was found that thickness of concrete and shotcrete in lining had negligible effect on the freezing depth while the insulation had significant effect on it. In addition, because the freezing depth is greatly affected by the thermal conductivity of the ground behind the lining in the period of cold weather, these effects should be considered in the estimation of the insulation thickness.

• Journal of the Korea institute for structural maintenance and inspection
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• v.18 no.4
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• pp.59-66
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• 2014

Insulation of rooftop is one of the major performance to energy-saving construction. Further, waterproofing performance is also important. For such a reason, it is need to develop waterproofing method containing thermal insulation property. This study was wanted to evaluate thermal insulation performance about the composite waterproofing method of thermal supplement type that is developed recently. As a result of waterproofing performance test, every test item was showed over the performance standards of KS (Korean (Industrial) Standards). And the result of thermal insulation performance test, the highest temperature in the styrofoam box was $25.91^{\circ}C$, the bubble sheet box was $17.28^{\circ}C$, the insulation sheet box was $15.47^{\circ}C$ and the waterproofing sheet box of thermal supplement type was $24.11^{\circ}C$. In observations of thermal bridges of sheet's joint, thermal bridges was not identified at the sheet's joint. As a result, composite waterproofing method of thermal supplement type is interpreted to have thermal insulation performance.

• Bulletin of the Korean Space Science Society
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• 2004.04a
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• pp.71-71
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• 2004

KSLV-I 추진기관 기체공급계는 상부의 산화제 탱크로부터 나온 산화제 주배관이 하부의 연료탱크를 관통하여 엔진공급계로 이어지도록 구성되어 있다. 연료탱크에는 산화제 배관의 관통을 위한 tunnel이 구성되어 있으며 배관과 tunnel은 일정한 간격을 유지하게 된다. 배관과 연료탱크 사이의 열전달을 줄이기 위하여 산화제 배관에 단열재를 적용할 수 있으나, 이 경우 배관의 운송, 조립시에 handling이 힘들게 되고, 특히 발사체에 조립된 후에 발생하는 단열재의 파손 및 성능감소에 대한 유지보수가 불가능하다. (중략)

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 1994.05a
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• pp.88-91
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• 1994

최근 국내에서도 시설원예가 급격하게 보급되고 있는 실정이다. 하지만, 시설원예가 에너지 소비형의 농경방식이라 지적되고 있는바 에너지절약형 온실의 개발이 필요할 것으로 판단되어, 본 실험실에서는 본 연구와 관련하여 비닐하우스의 벽체를 이중으로 하여 이중벽사이에 단열입자를 송풍기의 케이싱내로 직접 통하게하는 직송방식으로 충전ㆍ회수하는 실험을 실시한 바가 있으며, 그 결과 외기온의 평균이 -4.9$^{\circ}C$인 겨울철 야간에 입자를 충전한 이중비닐 하우스의 내부온도는 평균 9.8$^{\circ}C$로 단열성이 우수함을 알 수 있었다.(중략)

• 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.

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.331-332
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• 2009

The purpose of this study was to evaluate the effect of rejct fly-ash and blast-furnace slag on hydration heat and strength development of ternary system cement and concrete. Main experimental variables were performed fly-ash contenes (20%) and rejct fly-ash contents (20%) and slag contents (50%, 55%). The hydration heat and insulation temperature, strength development were measured to analyze the concrete of ternary system cement

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.2
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• pp.449-454
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• 2010

In this paper, flow characteristics of R600a in an adiabatic capillary tube were investigated employing the homogeneous flow model. The model is based on fundamental equations of mass, energy and momentum which are solved simultaneously. Two friction factors(Churchill) and viscosity(McAdams) are comparatively used to investigate the flow characteristics. Thermodynamic and transport properties of R600a are calculated employing EES property code. Flow characteristics analysis of R600a in an adiabatic capillary tube is presented to offer the basic design data for the operating parameters. The operating parameters considered in this study include condensation temperature, evaporation temperature, subcooling degree and inner diameter tube of the adiabatic capillary tube. The main results were summarized as follows: condensation and evaporation temperature, inlet subcooling degree and inner diameter tube of an adiabatic capillary tube using R600a have an effect on length of an adiabatic capillary tube. The length of an adiabatic capillary tube using R600a is expressed to the correlation shown in Eq. (15).

• Proceedings of the Korean Society of Disaster Information Conference
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• 2015.11a
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• pp.138-140
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• 2015

건축물에서 단열재는 일정한 온도를 유지하도록 하려는 부분의 바깥쪽을 피복하여 외부로의 열손실이나 열의 유입을 적게 하기 위한 재료이다. 단열재는 소재(素材) 자체의 열전도율(熱傳導率)이 작은 것이 바람직하나, 대부분 열전도율이 그다지 작지 않다. 그러므로 대개의 경우 열전도율을 작게 하기 위해서 다공질(多孔質)이 되도록 만들어 기공(氣孔) 속의 공기의 단열성을 이용한다. 일반적으로 재료의 밀도가 크면 열전도율 값이 크게 되는 경향이 있다. 이에 본 연구에서는 경량골재인 펄라이트의 입자 크기별 열전도율을 측정하여 단열재로서 사용여부를 판단하고자 한다.