• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.21 no.1
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• pp.41-48
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• 2009

The present study has been performed to investigate the thermal characteristics of under-ventilated compartment fire which is a typical fire condition in structures. A series of fire experiments was conducted to characterize the thermally driven flow in a 2/5 scale ISO 9705 fire compartment. Three different fuels were used in this test series, methane gas, heptane pool, and polystyrene pellets fire. In order to measure accurate temperature, double shield aspirated thermocouples reducing the effect of radiative energy exchange on temperature measurement were used in addition to bare bead thermocouples. The upper layer temperature for well ventilated fire was increased with increasing heat release rate, but it was slightly decreased for under-ventilated fire. The measured temperatures in the upper layer at the front sampling location were higher than at the rear. Thermal characteristics through the doorway were also analysed for a wide range of heat release rates. This study provides a comprehensive and quantitative assessment of fire behavior for under-ventilation condition of fire.

• Journal of Environmental Science International
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• v.12 no.10
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• pp.1101-1108
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• 2003

We studied the relationship between a civil affair occurrence of bad smell and meteorological conditions around Seongseo district for recent 2 years. The results were as follows; (1) The civil affair occurrence days of bad smell were concentrated from May to August. (2) Daily mean temperatures were mostly 20∼28$^{\circ}C$ and daily mean relative humidities were 60∼80%. (3) Wind speeds were mostly less than 2㎧(75%), and wind directions were southerly winds(50%). It was hardly occurred for relatively well-ventilated conditions in cases of wind speeds 2㎧ over. And the Lagrangian particle dispersion model were used to figure out the transport route in a civil affair occurrence days of bad smell. It was found that the south-western winds transported the bad smelling materials from Jungni-dong(the place of source) to the housing complex located along a piedmont district.

• Fire Science and Engineering
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• v.27 no.2
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• pp.31-39
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• 2013

The Fire Dynamics Simulator (FDS) has been applied to simulate a full-scale pool fire in well-confined and mechanically ventilated multi-compartments representative of nuclear power plant. The predictive performance of FDS was evaluated through a comparison of the numerical data with experimental data obtained by the OECD/NEA PRISME project. To identify clearly the FDS results regarding to the user-dependence in the process of FDS implementation except for the intrinsic limitation of FDS such as simple combustion model, only the over-ventilated fire condition was chosen. In particular, the importance of accurate boundary conditions (B.C.) in mechanically ventilated system were discussed in details. It was known from FDS results that the B.C. on inlet and outlet vents did significantly affect the thermal and chemical characteristics inside the compartments. Finally, it was confirmed that the FDS imposed an accurate ventilation B.C. provided qualitatively good agreement with temperatures, heat fluxes and concentrations measured inside the nuclear-type multi-compartments.

• Journal of Bio-Environment Control
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• v.23 no.4
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• pp.391-400
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• 2014

The number of large scale greenhouses has recently been increasing to cope with mass consumption of agricultural product. Korean government announced a new development plan for constructing greenhouse complex in reclaimed lands for the purpose of improvement in exports and activation of domestic market of agricultural product. Wind environment in the reclaimed land is totally different from that of inland area, and it can give a strong influence on ventilation performance of naturally ventilated greenhouse facilities. In this study, internal airflow analysis of naturally ventilated greenhouse built on a reclaimed land was conducted using wind tunnel and PIV for validation research. Later, the PIV measured results will be used to improve the accuracy of 3 dimensional CFD simulation in the future. Wind profile at a reclaimed land was produced using ESDU program and it was applied to the wind tunnel. The calculated error was only 5% and 0.96 of correlation coefficient, implying that the computed profiles were designed properly. From the measured results, when external wind speed changed from $1m{\cdot}s^{-1}$ to $1.5m{\cdot}s^{-1}$, air velocities inside the greenhouse which PIV measured were also increased proportionately in case of both side vent open and side-roof vent open. Considering reduced ratio of air velocity inside the greenhouse, it was measured a minimum of 40% in case of side vent and 30% in case of side-roof vent compared with external wind speed from each vent type. From the quantitative and qualitative PIV analysis, the PIV measured results indicated that there were well ventilated and stagnant areas in the greenhouse according to external wind condition as well as ventilation design.

• Fire Science and Engineering
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• v.27 no.2
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• pp.80-88
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• 2013

The validation of Fire Dynamics Simulator (FDS) was conducted for the under-ventilated fire in well-confined multi-compartments representative of nuclear power plant. Numerical results were compared with experimental data obtained by the OECD/NEA PRISME project. The effects of the numerical boundary conditions (B.C.) in ventilated system and the flame suppression model applied within FDS on the thermal and chemical environments inside the compartment were discussed in details. It was found that numerical B.C. on the vent flow resulting from over-pressure at ignition and under-pressure at extinction should be considered carefully in order to predict accurately the species concentrations rather than temperatures and heat fluxes inside the multi-compartment. The default information of suppression model applied within FDS resulted in artificial phenomena such as flame extinction and re-ignition, and thus the FDS results on the under-ventilated fire showed good agreement with the experimental results as the modified suppression criteria of the fuel used was adopted.

• Journal of The Korean Society of Agricultural Engineers
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• v.50 no.1
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• pp.25-37
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• 2008

When livestock facilities in Korea have been changed larger and denser, rearing conditions have been getting worse and the productivity of animal production have been decreased. Especially in the cold season, the minimized ventilation has generally been operated to save energy cost in Korea resulting in very poor environmental condition and high mortality. While the stability, suitability, and uniformity of the rearing condition are the most important for high productivity, the ventilation configuration is the most important to improve the rearing condition seasonally. But, it is so difficult to analyze the internal air flow and the environmental factors by conducting only field experiment because the weather condition is very unpredictable and unstable as well as the structural specification can not be easily changed by the researchers considering cost and labor. Accordingly, an aerodynamic computer simulation was adopted to this study to overcome the weakness of conducting field experiment and study the aerodynamic itself. It has been supposed that the airflow is the main mechanism of heat, mass, and momentum transfers. To make the simulation model accurately and actually, simplified pig models were also developed. The accuracy of the CFD simulation model was enhanced by 4.4 % of errors compared with the data collected from field experiments. In this paper, using the verified CFD model, the CFD computed internal rearing condition of the mechanically ventilated pig house were analyzed quantitatively as well as qualitatively. Later, this developed model will be computed time-dependently to effectively analyze the seasonal ventilation efficiency more practically and extensively with tracer gas decay theory.

• Journal of the Korean Home Economics Association
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• v.44 no.3 s.217
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• pp.103-113
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• 2006

The purpose of this study was to determine the present condition of sick house syndrome of newly built apartments a mid-sized city. The questionnaire survey was carried out from $19^{th}\;to\;22^{nd}$ of May 2004, with respondents consisting of 160 households living in two apartment complexes of Cheongju. Their residency periods after moving in were within $six{\sim}ten$ months. From the survey results of the respondents, sick house syndrome items revealed high percentages with the highest value of 49.3%. The respondents answered that they knew relatively well about sick house syndrome but they had no knowledge about 'bake-out'. The response percentages of sick house syndrome items in E complex, consisting of $106m^2$ (32 pyeong) size units, were significantly higher than those in A complex, consisting of $76m^2$ (23 pyeong) size units. This result suggests that the pollution levels emitted from interior materials in larger sized apartment units are higher than those in small sized units. The response percentages of sick house syndrome items in houses with fulfilled ventilation which had been ventilated before or after moving in were lower than in houses not ventilated.

• International Journal of Naval Architecture and Ocean Engineering
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• v.8 no.1
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• pp.22-37
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• 2016

This article investigates numerical modeling of surface piercing propeller (SPP) in unsteady open water condition using boundary element method. The home code based on BEM has been developed for the prediction of propeller performance, unsteady ventilation pattern and cross flow effect on partially submerged propellers. To achieve accurate results and correct behavior extraction of the ventilation zone, finely mesh has generated around the propeller and especially in the situation intersection of propeller with the free surface. Hydrodynamic coefficients and ventilation pattern on key blade of SPP are calculated in the different advance coefficients. The values obtained from this numerical simulation are plotted and the results are compared with experiments data and ventilation observations. The predicted ventilated open water performances of the SPP as well as ventilation pattern are in good agreement with experimental data. Finally, the results of the BEM code/experiment comparisons are discussed.

• Journal of the Korean Society of Clothing and Textiles
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• v.41 no.6
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• pp.1141-1153
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• 2017

The wearing of the correction bra is very important to stabilize the shape of an implant after breast enlargement surgery; however, the verification of the wearing effect is insufficient. This study surveyed women who experienced breast augmentation surgery, to investigate wearing condition and satisfaction with bras worn immediately after surgery and during the recovery period as well as to collect basic data for the development of an improved patient bra. The study results are as follows. More than half of the respondents stated that they wear a cupless brassiere. As a result of the satisfaction by brassiere types, the cupless bra showed the highest satisfaction. The most important factor in choosing a patient's bra after breast augmentation surgery was the "degree of breast compression". Through the application of the results of this study, the necessity of development of the brassiere for breast enlargement patients with improved function and comfort was understood. It is therefore necessary to improve the function of holding the shape of the breast and applying appropriate pressure as well as designing the ventilated material without skin irritation that is superior to the existing brassieres.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2009.04a
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• pp.93-99
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• 2009

본 연구는 ISO-9705 표준화재실의 40% 축소모형실험 결과와 FDS 화재해석 결과의 비교분석을 통하여 FDS 화재해석 모델에 적용된 CO 와 soot의 생성율(yield rate)에 기초한 접근방식의 타당성을 검토한다. 일반적으로 생성율은 연료적인 특성인 동시에 공간의 환기조건이나 열적조건등에 영향을 받게 된다. 그러나 FDS 해석에 적용되는 연료의 생성율은 환기량이 충분한 상태(well ventilated condition)에서 측정되어진 물성으로써 공간내부의 CO와 soot 농도는 연료의 종류와 화원의 크기에 의해서만 결정된다. 따라서 환기조건과 연료특성에 따른 화재공간 내부에서의 CO와 soot 농도를 측정하여 이 결과를 FDS 시뮬레이션 결과와 직접 비교함으로써 환기조건 및 연료종류에 따른 CO 와 soot의 생성율 개념의 타당성을 고찰해보고자 한다.