• Journal of Environmental Science International
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• v.4 no.2
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• pp.169-180
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• 1995

This Daper presents effective simulation of the dispersion of thermal discharge which can be relesed at Boryong power plant. Applied numerical models are finite difference method for hydrodynamic analysis and Masch-model comprised of conditions for ambient current velocity. Application of these models is done in Cheonsu Bay Summing up the results of this study are as follows; 1. It is found that the result for measurements of temperature appears high at southwardly Songdo on flood. The reason is that tidal currents which flowed north direction were accompanied with southwardly dispersed thermal discharge. A minute Particle of thermal Plume has a tendency to dispels inward Deacheon Bay. 2. According to the results of numerical experiment, maximum distance for thermal discharge dispersion appeared 10.8 km at lower part and 8.6 km at upper part with power plant outlet as starting point. 3. Comparative the numerical simulation and Airbone Multispectral Scanner indicated that thermal discharge should be verified separative phenomena. The simulated results were compared with field data set showing good agreement. It is concluded that these model can be simulated well.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.3
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• pp.297-303
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• 2007

Orimulsion, a bitumen-in-water emulsified fuel, has been used throughout the world as a substitute fuel for heavy oil and coal. Orimulsion has relatively high levels of sulfur, nickel, and vanadium, compared to other fuel oils and coals, and has been the subject of much debate regarding the environmental impacts. In Korea, Y power plant has operated boilers with Orimulsion as a fuel, and they has some drawbacks during the plant operation, such as plume opacity. In this study, we investigated the cause of formation mechanism and factors for the plume opacity by investigating the operation data, and measuring the particle size distribution at EP(Electrostatic Precipitator), FGD(Fuel Gas Desulfurization) and TMS(Telecommunications Management System) units. Resulting data showed the primary particles below 1 ${\mu}m$ formed were regrown by the recombination of $SO_3$ in wet-limestone FGD process, and thus the secondary particles are induced to cause the plume opacity.

• Journal of computational fluids engineering
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• v.8 no.4
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• pp.41-49
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• 2003

This study presents a numerical model to analyze dynamic thermal behavior of a hot chuck designed for flip-chip bonders. The hot chuck of concern is a heater which has been specifically developed for accomplishing high-speed and ultra-precision soldering. The characteristic features are radiative heat source and the heating tool made of a material of high thermal diffusivity. A physical modeling has been conducted for the network of heat transport. A simplified finite volume model is deviced to simulate time-dependent thermal behavior of the heating tool on which soldering is achieved. The reliability of the proposed numerical model is verified experimentally. A series of numerical tests illustrate the usefulness of the numerical model in design analysis.

• Journal of Korean Society of Water and Wastewater
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• v.18 no.4
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• pp.437-444
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• 2004

To control algal bloom in reservoirs in Korea, artificial circulation systems have been applied. Diffuser block aeration systems have been increasingly used in Korean reservoirs especially for shallow ones. However, there has been no sound theoretical background for the design and operation of the system. Also there has not been sufficient post-installation studies to validate the effectiveness of the system. As a result, it has been repeatedly reported that the success of the system is not certain. Proper consideration on thermal stratification regimes of reservoirs and flow dynamics induced by bubble plumes are essential elements in design processes of the aeration system. This paper discusses the current methods in the design of diffuser type aeration system and suggests a new design method based on fluid mechanical theory. Example calculations were discussed using observed data of the Yeoncho Dam and it seems that the results represent the current situation successfully.

• International Journal of Aeronautical and Space Sciences
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• v.6 no.1
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• pp.61-70
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• 2005

The currently developed propulsion system(PS) is composed of propellant tank, valves, thrusters, interconnecting line assembly and thermal hardwares to prevent propellant freezing in the space environment. Comprehensive engineering analyses in the structure, thermal, flow and plume fields are performed to evaluate main design parameters and to verify their suitabilities concurrently at the design phase. The integrated PS has undergone a series of acceptance tests to verify workmanship, performance, and functionality prior to spacecraft level integration. After all the processes of assembly, integration and test are completed, the PS is integrated with the satellite bus system successfully. At present, the severe environmental tests have been carried out to evaluate functionality performances of satellite bus system. This paper summarizes an overall development process of monopropellant propulsion system for the attitude and orbit control of LEO(Low Earth Orbit) observation satellite from the design engineering up to the integration and test.

• Journal of Soil and Groundwater Environment
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• v.21 no.6
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• pp.114-127
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• 2016

An increase of groundwater flux in BHE system creates that ground temperature (locT) becomes lower in summer and higher in winter time. In other words, it improves significantly the performance of BHE system. The size of thermal plume made up by advection driven-flow under the balanced energy load is relatively small in contrast to the unbalanced energy load where groundwater flow causes considerable change in the size of thermal plume as well ground temperature. The ground temperatures of the up gradient and down gradient BHEs under conduction only heat transport are same due to no groundwater flow. But a significant difference of the ground temperature is observed between the down gradient and up gradient BHE as a result of groundwater flow-driven thermal interference took placed in BHE field. As many BHEs are designed under the obscure assumption of negligible groundwater flow, failure to account for advection can cause inefficiencies in system design and operation. Therefore including groundwater flow in the design procedure is considered to be essential for thermal and economic sustain ability of the BHE system.

• Journal of computational fluids engineering
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• v.22 no.1
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• pp.43-50
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• 2017

Thermal flowfield of a micro turbojet engine was computationally investigated for exhaust nozzles with different aspect ratio and curvature. Special attention was paid to maximum and average temperature of the nozzle surface and the exhaust nozzle plume. The IR signatures of the micro turbojet engine nozzle were then calculated through the narrow-band model based on thermal flowfield data obtained through CFD analysis. Finally, in order to check the similarity of thermal flowfields and IR signature of the sub-scale micro turbojet engine model and the full-scale UCAV propulsion system, several non-dimensional parameters associated with temperature and optical property of plume were introduced. It was shown that, in spite of some differences in actual values of non-dimensional parameters, the scaling characteristics on spectral feature of IR signature and effects of aspect ratio and curvature of nozzle configuration remain similar in sub-scale and full-scale cases.

• Transactions of the Korean Society of Mechanical Engineers
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• v.14 no.6
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• pp.1645-1651
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• 1990

The steady laminar mixed convection from two finite vertical parallel plates has been studied by numerical procedure. The governing equations are solved by the finite difference method and point successive over relaxation scheme at R3=100-1000, Gr=0-10$^{6}$ , Pr=0.71 and dimensionless plate spacing b/$\ell$=0.05-0.1. The plume interaction caused by the thermal interference of two plates is observed. As Reynolds numbers are increased, optimum plate spacings are moved to narrow spacings at the same Grashof number, and as Grashof numbers are increased, to wide spacings at the same Reynolds number.

• Fire Science and Engineering
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• v.17 no.3
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• pp.13-19
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• 2003

In this paper, numerical calculations are conducted to predict the characteristics of the heat transfer and smoke propagation in a cydodrome. The gas flow velocity and temperature around the origin of the fire is obtained by using a plume model and the turbulent flow characteristics are considered by standard $textsc{k}$-$\varepsilon$ turbulent model. In this study, the transient thermal behavior can be used for designing fire detection of large rooms.

• Journal of Environmental Science International
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• v.7 no.2
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• pp.233-241
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• 1998

This study Is concerned with properties of a thermal convection in a stably stratified Boussinesq fluid caused by partial heating at the lower boundary. For thins purpose, two-dimensional, nonrotating system was employed. U the heating is very strong, convection takes the form of a turbulent plume. Othenuse, remains laminar. If the partial heating at the bottom boundary Is symmetric. the convection takes the form of a trubuient plume. Otherwise remains but beating form Is not so signiacant as to alter the vergence in the lower layer at the center of the partial heating area. The temperature perturbation is characterized by the temperature 'Cross-Over' over the partial heating area. These features are cleared ac- cording to the Increase of temperature difference between the center and side part of the bottom boundary.