• 한국지반환경공학회 논문집
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• 제3권1호
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• pp.57-66
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• 2002

도로포장설계시 일반적으로 동상방지층을 노상층에 포함시키지 않고 단지 노상층의 CBR을 산정하여 그 강도에 적합한 도로포장구조를 결정하고 있다. 그러나, 현재 추세는 동상방지층을 노상층에 포함시켜 포장구조를 설계하고 있다. 동상방지층을 포함한 노상층의 평균 CBR을 사용하는 경우 노상층만의 CBR에 비해 상대적으로 큰 강도를 나타내므로 포장구조 두께는 감소한다. 그러나, 동상방지층을 포함한 노상층의 평균 CBR 산정식이 별도로 규정되어 있지 않으므로 CBR 결정에 많은 혼선을 가져오고 있다. 따라서, 본 연구에서는 동상방지층을 포함한 노상층의 평균 CBR을 산정하기 위하여 실내 및 현장 CBR 시험을 실시하였다. 실험결과를 근거로 노상층의 평균 CBR 산정에 편리한 수정식을 제안하였다. 또한, 노상층만의 CBR을 사용한 포장설계시와 동상방지층을 포함한 노상층의 평균 CBR을 사용한 포장설계시 포장두께를 비교하여 경제성을 검토하였다.

• 설비공학논문집
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• 제8권2호
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• pp.299-306
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• 1996

This work presents an analytical model, so called modified LMTD method, to predict the thermal performance of finned-tube heat exchanger under frosting conditions. In this model, the total heat transfer coefficient and effective thermal conductivity of the frost layer were defined as a function of frost surface temperature. The surface temperature of the frost layer formed on the heat exchanger was calculated through the analysis of the heat and mass transfer process in the air and frost layer. To examine the validity of this analytical model, the computed results from the present model, such as heat transfer rate, frost mass and thickness of frost, were compared with the ones of the expermental work and LMED method.

• 대한기계학회논문집B
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• 제27권8호
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• pp.1114-1121
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• 2003

A mathematical model considering the air side and the frost layer is presented to predict the frost layer growth. The standard k-$\varepsilon$ model for the air flow and the diffusion and energy equations for the frost layer are employed. The numerical results are compared with experimental data to validate the present model, and agree well with experimental data within a maximum error of 10%. The present model predicts well the frost properties and heat and mass transfer with respect to the frosting time. The variation of total heat transfer strongly depends on the operating condition, and has a similar trend to that of the sensible heat transfer. The frost properties along the flow direction are also investigated.

• 한국지반공학회지:지반
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• 제14권1호
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• pp.49-58
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• 1998

폐타이어가 지반의 동상방지 건설재료로서 재사용될 수 있는지를 연구하였다. 동상방지에 대한 폐타이어의 기본적인 효과를 검토하기 위해 화강풍화토에 폐타이어가루를 몇 가지의 비율로 혼합해서 준비한 시료로서 영하 $17^{\circ}$하에서 동상시험과 화강풍화토에 대한 동결깊이시험을 실내에서 수행하였다. 역청포장의 보조기층 바로 아래에 폐타이어조각을 혼합한 쇄석층을 동상방지층으로 둠으로서 실용상으로 효과적이라는 사실을 알게 되었다. 그리고 이 동상방지 층의 소요두께와 동결 지수와의 관계식을 제안하였다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.2091-2096
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• 2007

This paper presents a mathematical model for predicting the frost behavior formed on heat exchanger fins, considering fin heat conduction under frosting condition. The model is composed of air-side, the frost layer, and fin region, and they are coupled to the frost layer. The frost behavior is more accurately predicted with fin heat conduction considered (Case A) than with a constant fin surface temperature assumed (Case B). The results indicate that the frost thickness and heat transfer rate for Case B are over-predicted in most regions of the fin, as compared to those for Case A. Also, for Case A, the maximum frost thickness varies little with the fin length variations, and the extension of the fin length over 30 mm contributes insignificantly to heat transfer.

• 한국철도학회논문집
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• 제19권4호
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• pp.506-514
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• 2016

철도 현장에 실험용 자갈궤도와 콘크리트궤도를 설치한 후 겨울철에 동결심도와 동상량을 측정하였다. 그 결과 같은 동결지수일 때 자갈궤도보다 콘크리트궤도의 동결심도가 깊게 나타나는 경향을 보였다. 또한 자갈궤도는 하부에 XPS, PE골재층을 포설할 경우 동결심도가 크게 감소하였고, 콘크리트궤도에서는 입도조정층의 두께를 늘릴 경우 동결심도가 감소하는 경향을 보였다. 동상량 역시 자갈궤도에서는 하부에 XPS, PE골재층을 설치할 경우 감소하였고, 콘크리트궤도에서는 입도조정층의 두께를 증가시킬 경우 감소하는 경향을 보였다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 1999년도 토목섬유 학술발표회 논문집
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• pp.117-128
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• 1999

Geosynthetics have been studied especially Korean Railway earth works from the outset and have proved successful in both technical and economic terms. Hitherto Geosynthetics have been given consideration chiefly in dimensioning the requisite track subbase thickness, but have not been considered when calculating the thickness of the frost protection layer. this often made it impossible to reduce the thickness of the subbase. The article therefore puts forward a proposal for considering the German Geosynthetics in dimensioning the requisite thickness of the frost protection layer.

• 대한기계학회논문집B
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• 제20권3호
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• pp.1096-1105
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• 1996

A theoretical model of the frost formation has been presented to investigate the characteristics of the growth of frost layer by considering molecular diffusion of water vapor and heat generation caused by sublimation of water vapor in the frost layer. The present model was compared with existing experimental data as well as a previous model. The difference between the present model and existing experimental data was found to be about 6 percent. An analysis for the behavior of frost formation using present model shows a good agreement with the trend for a number of experimentally observed features. The present analysis can also provide the physical understanding on the phenomena of the frost formation.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2005년도 후기학술대회논문집
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• pp.234-235
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• 2005

In this experiment study, to acquire elementary data for explaining to generate frost layer in the fin - tube evaporator. the experiment condition is to supply air on 0.3m/s, 0.6m/s, 0.9m/s and inlet air temperature is 15$^{circ}C$, 20$^{circ}C$, 25$^{circ}C$ , supplied air relative humidity is 70%, 80, 90%. And brine temperature in the copper tube was kept -15$^{circ}C$ because, generally cooling temperature range is constantly -15$^{circ}C$ in the heat exchanger for air conditioning system. in conclusion, through this experiment, we did compare with frost layer and frost thickness in each condition and examine these data

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2005년도 전기학술대회논문집
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• pp.166-171
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• 2005

In this experiment study, to acquire elementary data for explaining to generate frost layer in the fin - tube evaporator. the experiment condition is to supply air on 0.3m/s, 0.6m/s, 0.9m/s and inlet air temperature is kept constantly $20^{\circ}C$, supplied air relative humidity is 70%, 80, 90%. And brine temperature in the copper tube was kept $-15^{\circ}C$ because, generally cooling temperature range is constantly $-15^{\circ}C$ in the heat exchanger for air conditioning system. in conclusion, through this experiment, we did compare with frost layer and frost quantity in each condition and examine these data