• Title, Summary, Keyword: Frost

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Evaluation of Frost Heave Prediction and Frost Susceptibility in Sample using JGS Test Method (일본 동상성판정기준을 적용한 시료의 동상예측 및 동상성 평가)

  • Kim, Young-Chin;Hong, Seung-Seo
    • Proceedings of the Korean Geotechical Society Conference
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    • pp.926-931
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    • 2008
  • This paper show two different standardized test methods(Japanese Geotechnical Society; JGS 2003). One test is a "Test Method for Frost Heave Prediction Test, JGS 0171-2003", and the other test is a "Test Method for Frost Susceptibility, JGS 0172-2003". The purpose of this test is to obtain the freezing rate(freezing speed), frost heave ratio(heave to sample height), frost heave rate(heaving speed), and other parameters to be used for frost heave prediction and determine the frost susceptibility by freezing test with water intake. This method shall be used to predict the frost heave in frozen ground and evaluate the frost susceptibility of natural and replacement materials.

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An Experimental Study of Frost Formation on the Horizontal Cylinder (수평 실린더 표면의 착상에 대한 실험적 연구)

  • Paik, Sang-Jin;Lee, Yoon-Been;Ro, Sung-Tack
    • Proceedings of the KSME Conference
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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.

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Modeling for Frost Growth on a Cold Plate (냉각 평판에서 서리 성장 모델링)

  • Yang, Dong-Keun;Lee, Kwan-Soo
    • Proceedings of the KSME Conference
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    • pp.1546-1551
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    • 2004
  • This paper presents a mathematical model to predict the frost properties and heal and mass transfer within the frost layer formed on a cold plate. The laminar flow equations for the air-side are analyzed. and the empirical correlations of local frost properties are employed in order to predict the frost layer growth. The correlations of local frost density and effective thermal conductivity of frost layer, obtained from various experimental conditions, are derived as functions of various frosting parameters (Reynolds number, frost surface temperature, absolute humidity and temperature of moist air, cooling plate temperature, and frost density). The numerical results are compared with experimental data and the results of various models to validate the present model, and agree well with experimental data within a maximum error of 10%. The heat and mass transfer coefficients obtained from the numerical analyses are presented, as the results, it is found that the model for frost growth using the correlation of heat transfer coefficient without solving air flow have a limitation in its application.

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Numerical Study of Performance Variation Under Frost and Non-frost Condition of Refrigerating System in the Refrigerator Truck (냉동탑차용 냉장시스템의 착상 및 무착상 상태에서의 성능변화에 관한 해석적 연구)

  • Kim, Sang-Hun;Myung, Chi-Wook;Cho, Hong-Hyun
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.23 no.11
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    • pp.733-740
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    • 2011
  • To analyze the cooling performance in the refrigerator truck according to frost growth, the analytical model of refrigeration system was developed under frost and non-frost condition using EES. The system performance was analyzed with outdoor temperature, storage temperature, outdoor front air velocity and compressor speed in order to investigate the system performance characteristics with operating conditions. Besides, the system performance under frost condition was compared with that under non-frost condition. As a result, the frost thickness was 0.9 mm when the refrigerating capacity of frost condition was decreased by 30%. The maximum of the system COP was shown at compressor speed of 1500 rpm for non-frost and frost condition, simultaneously. The performance under frost condition was more sensitive to the operating condition compared to that under non-frost condition.

A Characteristics Study on the Visualization and Heat Transfer of the Frost Formation Structure Variation by Control Plate Surface Temperature (표면온도 제어에 의한 착상층 구조변화의 가시화 및 열전달 특성 연구)

  • Kim Kyung-Chun;Ko Choon-Sik;Jeong Jae-Hong;Ko Young-Hwan;Shin Jong-min
    • 한국가시화정보학회:학술대회논문집
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    • pp.55-58
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    • 2002
  • To control the frost formation, a temperature variation of the cooling plate and characteristics on hydrophilic and hydrophobic surfaces was attempted. As a temperature variation of the cooling plate, being closely related to the frost layer density of frost layer is found to be affected by the melting process inside the frost layer during the heating period. At characteristics on surface, completely different structures of frost are appeared in the initial stage of frost formation due to the difference in surface conditions, while those effects are vanished with time. It is found that the frost thickness, density and heat flux characteristics are closely associated with the frost structure.

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A Study of Frost Formation on Different Hydrophilic Surfaces (다른 친수성능을 가진 두 표면에서의 착상에 관한 연구)

  • 김철환;신종민;하삼철
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.14 no.6
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    • pp.519-524
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    • 2002
  • An experimental study has been conducted to investigate the effects of surface energy on frost formation. Test samples with two different surfaces are installed in a wind tunnel and exposed to a humid airflow. Dynamic contact angles (DCA) for these surfaces are $23^{\circ}\;and\;88^{\circ}$, respectively. The thickness and the mass of frost layer are measured and used to calculate the frost density while frost formation is visualized simultaneously with their measurements. Results show that frost density increases as time increases at specific test conditions. The air Reynolds number, the airflow humidity and the cold plate temperature are maintained at 12,000, 0.0042 kg/kg and $-21^{\circ}C$, respectively. The surface with a lower DCA shows a higher frost density during two-hour test, but no differences in the frost density have been found after two hours of frost generation. Empirical correlations for thickness, mass and density are assumed to be the functions of the test time and DCA.

Experimental assessment of the effect of frozen fringe thickness on frost heave

  • Jin, Hyun Woo;Lee, Jangguen;Ryu, Byun Hyun;Shin, Yunsup;Jang, Young-Eun
    • Geomechanics and Engineering
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    • v.19 no.2
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    • pp.193-199
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    • 2019
  • A frozen fringe plays a key role in frost heave development in soils. Previous studies have focused on the physical and mechanical properties of the frozen fringe, such as overall hydraulic conductivity, water content and pore pressure. It has been proposed that the thickness of the frozen fringe controls frost heave behavior, but this effect has not been thoroughly evaluated. This study used a temperature-controllable cell to investigate the impact of frozen fringe thickness on the characteristics of frost heave. A series of laboratory tests was performed with various temperature boundary conditions and specimen heights, revealing that: (1) the amount and rate of development of frost heave are dependent on the frozen fringe thickness; (2) the thicker the frozen fringe, the thinner the resulting ice lens; and (3) care must be taken when using the frost heave ratio to characterize frost heave and evaluate frost susceptibility because the frost heave ratio is not a normalized factor but a specimen height-dependent factor.

An Experimental Study on Frost Heaving Characteristics of Soil Stabilized with the Additives (안정처리토의 동상특성에 관한 실험적 연구)

  • Kim, Jae-Young;Ju, Jae-Woo;You, Byung-Ok;Yang, Sung-Kee
    • Proceedings of the Korean Society of Agricultural Engineers Conference
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    • pp.215-218
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    • 2003
  • In order to study the frost heaving characteristics of soil stabilitized with a quick lime, a cement and a briquette ash, frost heaving tests were performed with 2 kinds of soil sampled at Chonbuk-Do area. Frost heaving of no-stabilizing soil compacted with water content greater than optimum water content was increased as the frost period was increased but in case of samples with water content smaller than optimum water content, the frost period gave no affect about increase and decrease of the frost heaving. Both frost heaving of stabilizing and no-stabilizing soil with water content greater than optimum water content was decreased with the increase of the repetition number of freezing and thawing. There was no increase or decrease of frost heaving in the frost heaving test after 5 times of freezing and thawing.

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Evaluation of Ground Water Level Effect on Frost Heaving in Road Pavements (도로 포장체에서 동상에 대한 지하수위 영향 평가)

  • Kweon, Gichul;Lee, Jaehoan
    • International Journal of Highway Engineering
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    • v.15 no.1
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    • pp.47-56
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    • 2013
  • PURPOSES: This study is to evaluate a ground water level effect on frost heaving in road pavements. METHODS: The effects of water table on frost heaving in pavement systems were evaluated from the mechanical analysis using FROST program. The input parameters and boundary conditions were determined by considering climates, pavement sections, and material properties specially subgrade soil types in Korea. RESULTS: When the water table located above the freezing depth, amount of frost heaving caused by freezing the water in pavement itself was big enough to damage in pavement system, although pavement system consists of fully non-frost-susceptible materials with sufficient thickness of anti-freezing layer. The amount of frost heaving was decreased rapidly with increasing the distance between the water table and freezing depth. CONCLUSIONS: It was concluded that there is no engineering problems related with frost heaving in practical sense when the distance between freezing depth and water table is over 1.5m for having subgrade soils less than 50% of #200 sieve passing to meet specification on quality control in Korea.

Prediction of Frost Layer Growth on a Cold Plate (저온 평판에서의 서리층 성장 예측)

  • Jhee, Sung;Lee, Kwan-Soo;Yeo, Moon-Su
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.26 no.9
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    • pp.1325-1331
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    • 2002
  • This study presents a numerical model to predict the behavior of frost layer growth. The characteristics of the heat and mass transfer inside the frost layer are analyzed by coupling the air flow with the frost layer. The present model is validated by comparing with the several other analytical models. It has been known that most of the previous models cause considerable errors depending on the working conditions or correlations used in predicting the frost thickness growth, whereas the model in this work estimates the thickness of the frost layer more accurately within an error of 10% in comparison with the experimental data. Simulation results are presented for variations of heat and mass transfer during the frost formation and for the behavior of frost layer growth along the direction of air flow.