• 한국전산유체공학회:학술대회논문집
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• 2009.11a
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• pp.121-128
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• 2009

During a hypothetical high-pressure accident in a nuclear power plant (NPP), molten corium can be ejected through a breach of a reactor pressure vessel (RPV) and dispersed by a following jet of a high-pressure steam in the RPV. The dispersed corium is fragmented into smaller droplets in a reactor cavity of the NPP by the steam jet and released into other compartments of the NPP by a overpressure in the cavity. The fragments of the corium transfer thermal energy to the ambient air in the containment or interact chemically with steam and generate hydrogen which may be burnt in the containment. The thermal loads from the ejected molten corium on the containment which is called direct containment heating (DCH) can threaten the integrity of the containment. DCH in a NPP containment is related to many physical phenomena such as multi-phase hydrodynamics, thermodynamics and chemical process. In the evaluation of the DCH load, the melt dispersion rates depending on the RPV pressure are the most important parameter. Mostly, DCH was evaluated by using lumped-analysis codes with some correlations obtained from experiments for the dispersion rates. In this study, MC3D code was used to evaluate the dispersion rates in the APR1400 NPP during the high-pressure accidents. MC3D is a two-phase analysis code based on Eulerian four-fields for melt jet, melt droplets, gas and water. The dispersion rates of the corium melt depending on the RPV pressure were obtained from the MC3D analyses and the values specific to the APR1400 cavity geometry were compared to a currently available correlation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.3
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• pp.1519-1526
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• 2013

This study reviewed the capturing performance of a canopy hood used in some melting processes of a casting manufacturing factory through a site survey. In addition, this study compared and evaluated the flow field and pressure field for the plans to enhance the hazardous air pollutants collection capacity by using CFD model. The case-2(flange attached + double hood) can be improved in terms of collection performance, but is expected to increase in hood static pressure by about 70% more than the existing structure, so it was shown that its site applicability is not good. It is judged that the shape of case-3(flange attached + double cone attached) is most suitable to improve the suction efficiency. This is because a double cone is installed at the center of the opening to concentrate the flow rate on the edge of the hood and control the hume rising to the center of the hood without a static pressure rise via the slope of the cone.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.40 no.2
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• pp.60-67
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• 2017

A baggage handling system (BHS) in airport is an unified system for moving the passengers' baggage in designated time. Input baggage from the check-in counter travels to the baggage claim area or cargo handling terminal through this system. In particular, entryway BHS consists of conveyors, X-ray and sorters such as tilt-tray to send the baggage to departing airplane and it could have various problems for handling certain amount of baggage in restricted time such as baggage jamming at certain merge point. This causes systemic error such as delay of the time, omissions of the baggage and even breakdown of the equipment and inefficiency. Also the increasing maximum time of the baggage passing through the BHS could delay the flight schedule and finally decrease the service level. Thus, the algorithm for controlling the flow of the merge is essential to the system. The window reservation algorithm is the one of the most frequently used methods to control the merge configuration. Above all, the reserve location, so called reserve ahead point, that allocates the window is important for the performance of the algorithm. We propose the modified window reservation algorithm and the best reserve locations by changing the reserve ahead point in the induction conveyors. The effect of various reserve ahead points such as the capacity and utility of the system were analyzed and the most effective reserve ahead point combination was found. The total baggage processing time and the utilization of the tilt-tray are properly considered when choosing the optimal Reserve ahead point combination. In the layout of this study, the configuration of four conveyors merged into one tilt-tray is studied and simulation analysis is done by AutoMod(R), 3D simulation software. Through the simulation, the window reservation algorithm is effectively operated with the best combination of reserve ahead point which reduces the maximum baggage travel time.

• Journal of the Society of Naval Architects of Korea
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• v.43 no.5 s.149
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• pp.586-596
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• 2006

A 3-dimensional FDLB model with additional internal degree of freedom is applied for diatomic gases such as air, in which an additional distribution function is introduced. Direct simulations of aero-acoustic by using the applied model and scheme are presented. Speed of sound is correctly recovered. As typical examples, the Aeolian tone emitted by a circular column is successfully simulated even very low Mach number flow. Acoustic pressure fluctuations with the same frequency of the Karman vortex street compared with the pressure fluctuation around a circular column is captured. Full three-dimensional acoustic wave past a compact block like pentagon, furthermore, is also emitted in y direction as dipole like sound.

• Journal of environmental and Sanitary engineering
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• v.10 no.2
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• pp.79-88
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• 1995

The electrostatic precipitation of Auto- Bias has the advantages of a little of power consumption by the voltage to apply only at ionizer and the prevention of fire danger by current flow over. As this ionizer wire was used WXN- Pt material of diameter 90$\mu $m, that improved ion efficiency and safety, simplified a existing source of electric power by induced Auto- Bias voltage. Also, the new type collector used electric conductivity- film wag superior a electric safety and dust collection efficiency and was possible to wash it by water. As a experiment result of this Auto- Bias electrostatic collector, the induced Auto- Bias voltage by appling D.C 4.0∼6.0kV at ionizer was 1.3∼2.3kV and then the power consumption by applied voltage was 8- l8W. The pressure loss of collector by the amount of flowing was 6.1 OmmH$_{2}$O in 300m$^{3}$/hr and showed a safe state of the dust collection. The collection efficiency by particle size was 65.1-95.8% in 0.5∼5.0$\mu $m. After corona discharge of ionizer, the remains ozone concentration was found much lower than that of ACGIH or air pollution criteria in Korea.

• International Journal of Ocean System Engineering
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• v.1 no.3
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• pp.136-143
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• 2011

In this paper, three-dimensional free-surface flows are simulated by using two different numerical methods, the constrained interpolation profile (CIP)-based and finite volume (FV)-based methods. In the CIP-based method, the governing equations are solved on stationary staggered Cartesian grids by a finite difference method, and an immersed boundary technique is applied to deal with wave-body interactions. In the FV-based method, the governing equations are solved by applying collocated finite volume discretization, and body-fitted meshes are used. A free-surface boundary is considered as the interface of the multi-phase flow with air and water, and a volumeof-fluid (VOF) approach is applied to trace the free surface. Among many variations of the VOF-type method, the tangent of hyperbola for interface capturing (THINC) and the compressive interface capturing scheme for arbitrary meshes (CICSAM) techniques are used in the CIP-based method and FV-based method, respectively. Numerical simulations have been carried out for dam-breaking and wave-body interaction problems. The computational results of the two methods are compared with experimental data and their differences are observed.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.38 no.12
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• pp.1009-1015
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• 2014

The present study investigated the effects of non-equilibrium condensation with the angle of attack on the coefficients of pressure, lift, and drag in the transonic 2-D flow of NACA0012 by numerical analysis of the total variation diminishing (TVD) scheme. At $T_0=298k$ and ${\alpha}=3^{\circ}$, the lift coefficients for $M_{\infty}=0.78$ and 0.81 decreased monotonically with increasing ${\Phi}_0$. In contrast, for $M_{\infty}$ corresponding to the Mach number of the force break, $C_L$ increased with ${\Phi}_0$. For ${\alpha}=3^{\circ}$ and ${\Phi}_0=0%$, $C_D$ increased markedly as $M_{\infty}$ increased. However, at ${\Phi}_0=60%$ and ${\alpha}=3^{\circ}$, which corresponded to the case of the condensation having a large influence, $C_D$ increased slightly as $M_{\infty}$ increased. The decrease in profile drag by non-equilibrium condensation grew as the angle of attack and stagnation relative humidity increased for the same free stream transonic Mach number. At ${\Phi}_0=0%$, the coefficient of the wave drag increased with the attack angle and free stream Mach number. When ${\Phi}_0$ > 50%, the coefficient of the wave drag decreased as ${\alpha}$ and $M_{\infty}$ increased. Lowering ${\Phi}_0$ and increasing $M_{\infty}$ increased the maximum Mach number.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.35 no.3
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• pp.143-154
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• 2013

Purpose: This study was to find efficacy of integrin alpha2 (${\alpha}_2$) and epidermal growth factor receptor (EGFR) as tumor marker of oral squamous cell carcinoma (SCC) and clarify the selective cell death effect of anti-integrin ${\alpha}_2$ and anti-EGFR on SCC cells, additionally testify conjugated gold nanoparticles (GNP) with air plasma for selective cell death of oral SCC. Methods: Expression of integrin ${\alpha}_2$, EGFR on human SCC cells (SCC25) were examined by western blot. SCC25 cells were treated with anti-integrin ${\alpha}_2$, anti-EGFR and analysed by Hemacolor staining, immunoflorescence staining, FACS flow cytometry. Conjugated GNP with integrin ${\alpha}_2$, EGFR antibody were treated by air plasma on SCC cells. Results: Integrin ${\alpha}_2$ and EGFR were over-expressed on SCC25 cells than normal lung WI-38 cells. The cell viability rate of SCC25 cells treated with anti-integrin ${\alpha}_2$, anti-EGFR was lower than WI-38 cells. The concentration changes of nucleus, releasing cytochrome c and apoptosis inducing factor (AIF) from mitochondria to cytosol were observed. The changes of proteins related with apoptosis were observed. Increase of bax, bcl-xL, activation of caspase-3, -7, -9, and fragmentation of PARP, DFF45 and decrease of lamin A/C in SCC25 cells were observed. In FACS, increase of sub-$G_1$ and S phase was observed. Cell cycle related proteins, Such as cyclin D1, cyclin dependent kinase (CDK) 4, cyclin A, cyclin E, CDK 2, p27 were decreased. After SCC25 cells treated with conjugatged GNP-Integrin ${\alpha}_2$, GNP-EGFR, additionally air plasma, the cell death rate was significantly increased. Conclusion: Integrin ${\alpha}_2$, EGFR were over-expressed in oral SCC cells. Anti-integrin ${\alpha}_2$, anti-EGFR in SCC25 cells induced apoptosis selectively. When GNP-anti integrin ${\alpha}_2$, GNP-anti EGFR were treated with air plasma on SCC25 cells, cancer cells were died more selectively. GNP-anti integrin ${\alpha}_2$, GNP-anti EGFR with air plasma could be treatment choice of oral SCC.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2002.04a
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• pp.66-69
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• 2002

In this work, cost effective venting is considered by comparing flow rates of 5$m\ell$/min, 10$m\ell$/min, and 20$m\ell$/min. Studies were performed on a soil artificially contaminated with diesel oil (the initial TPH(Total Petroleum Hydrocarbon) concentration of 7098mg/kg), and nutrient condition was C:N:P rate of 100:10:1. The soil has a sandy texture with pH of 6.8, 2.16 ~2.38% organic matter, a total porosity of 47~52% and field capacity 16.2~ 17.2%. The column experiments was made of glass column of 60cm length and 10cm I.D. at controlled temperature of 2$0^{\circ}C$($\pm$2.5$^{\circ}C$). The efficiency of continuous flow rate of 5, 10 and 20$m\ell$/min resulted in separately 61.3%, 58.1%, and 55% reduction of initial TPH concentration(7098mg/kg). Hydrocarbon utilizing microbial count and dehydrogenase activity in air flow of 5$m\ell$/min were higher than those of the others. The first order degradation rate of n-alkanes ranging from C10 to C28 was higher than that of pristane and phytane as isoprenoids. The $C_{17}$/pristane and $C_{18}$phytane ratios for monitoring the degree of biodegradation were useful only during the early stages of oil degradation. Degradation contributed from about 89% to 93% of TPH removal. Volatilization loss of diesel oil in contaminated soil was about 7% to 11%, which was significantly small compared to degradation.n.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.3
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• pp.286-292
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• 2005

This study is to investigate the industrial boiler which can be significantly affected by the restriction of NOx. Note that the application of SNCR method to industrial boiler is usually blown as not feasible due to the insufficient residence time for proper mixing. The purpose of this study is to investigate the applicability of the SNCR system application to the industrial boiler, which produces 40 tons of steam per hour using heavy oil. For the industrial boiler with 3-D rectangular coordinate, the general coding are made fur various turbulence modeling such as turbulent flow, turbulent fuel combustion, thermal NO formation and destruction together with the NO reaction with reducing agents. Further, the incorporation of drop trajectory model is successfully made in 3-D rectangular coordinate with Lagrangian frame and the main swirl burner effect on the characteristics of flame is considered. As expected a short flame was created and thereby NOx is removed more efficiently by increasing the proper region of temperature for NO reduction reaction. The validation of program was made successfully by the comparison of experimental data. Based on the reliable calculation results, the SNCR method in a industrial boiler shows the possibility as one of viable NO reduction method by the use of well designed mixing air of reducing agent.