• Journal of Korea Soil Environment Society
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• v.2 no.1
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• pp.83-90
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• 1997

Aiming at the treatment of large volumes of gas with a low concentration of poorly water soluble VOC(Volatile Organic Compound), a new system is proposed: the combination absorption tower/bioreactor. In the scrubber part of the bioscrubbing system, the contaminating compounds are absorbed in a aqueous phase. The contaminated scrubbing liquid is transported to the bioreactor, where the compounds are biodegraded by aerobic microorganisms (mainly to carbon dioxide, water, and biomass). In this study, separation of a volatile organic compound(VOC) out of a waste gas stream has been carried out using a re-cyclable high boiling point extrant(HBE). The liquid stream containing a high boiling point entrant(HBE) scrubs the gas stream in a direct gas-liquid countercurrent contacting operation in a packed tower for the removal of said component from the gaseous stream. A packed-bed column using Pall Ring was set up in order to simulate practical conditions for the scrubbing tower. The liquid stream transported to the bioreactor is recovered and recycled to the scrubber. The model gas, which contained 400 mg/$\textrm{m}^3$ of toluene, at a rate of 100 L/min, flowed into the packed column where the scrubbing liquid trickled over the packing in countercurrent to the rising gas at 10~15L/min. The bioscrubber designed for large volume air streams containing VOCs showed removal efficiency up to 80% in an optimum operating conditions during the tests fer removing toluene from an air stream by scrubbing the air stream with HBE.

• Journal of Korean Society on Water Environment
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• v.22 no.5
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• pp.919-925
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• 2006

The regression models for the water temperatures of Ban Byeon Stream and Yong Jeon stream were developed using multi-regression method. It was also investigated that the applicability of the stream temperature prediction to two-dimensional numerical simulation to predict the vertical water temperature in Imha Reservoir. Air temperature and dew point as independent variables were selected to be applicable to cases with the different variation of flow rates. The data division of water temperature using a cutoff flow rate of $20m^3/s$ was found to reduce the prediction error of the stream temperature. The mean absolute percent error of the numerical simulation results of the vertical water temperature in Imha Reservoir using the regression models was 11%, which was only 4.3% lager than the simulation result using the measured stream temperature. Therefore, the regression models of the stream temperatures using multi-regression method applied in this study could be applied to predict the vertical water temperature in Imha Reservoir with a good accuracy.

• 한국연소학회:학술대회논문집
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• 2012.04a
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• pp.263-266
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• 2012

The characteristics of mild combustion and pollutant emission were investigated computationally with supplied air stream temperature and dilution rate in jet flame. The air was diluted with main combustion products. As dilution rate increased at fixed air temperature, the temperature distribution of burner inside was uniformed and the maximum mole fraction of CO and NO was decreased. In addition, emission indices for NO, CO, and $CO_2$ were compared with air temperature and dilution rate.

• Toxicological Research
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• v.5 no.2
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• pp.97-104
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• 1989

A new exposure system was developed to generate p-dinitrobenzene (p-DNB) containing atmosphere. A glass column was filled with small glass beads coated with the chemical. The p-DNB containing medium was heated to a temperature beyond the boiling point of p-DNB. A stream of air flow was forced to pass through the column and let it mixed with fresh air before introducing into an inhalation chamber. The concentration of p-DNB in the chamber air was measured by direct assaying the air directly and by sampling the chemical using a microfilter installed in the chamber.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2009.10a
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• pp.375-376
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• 2009

• Transactions of the Korean Society of Automotive Engineers
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• v.24 no.6
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• pp.677-683
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• 2016

In this study, the pressures due to air resistances on the models of 1, 2, 3 and 4 as the automotive bodies grafted on various spoilers are investigated through the flow analysis. Model 1 has the flat type and model 2 has the shape that a flat plane is projected. Model 3 is attached with the slanted plate and model 4 has the shape that two slanted plates are installed on both sides. At the flow streams on the models of 1, 2, 3 and 4, the flow velocities are shown to become highest above the roofs of automotive bodies. The maximum flow velocities are also shown at the beginning points at the roofs of car bodies on the side planes of automotive bodies. The maximum pressures of 102,500 to 102,553 Pa as air resistances are shown at the bumpers of the front car bodies. The flow velocities on the inlet and middle planes become nearly same at the models of 1, 2, 3 and 4. But these velocities on the inlet plane at model 2 projected with the spoiler of flat plate become lower than the models of 1, 3 and 4. The air streams throughout the models become uniform at all models. The flow stream is shown most uniformly at model 2 projected with the spoiler of flat plate. But the flow stream is shown most irregularly at model 3 projected with the spoiler of slanting plate. By using the result of this flow analysis, it is thought to reduce the power of car effectively in driving by changing the configuration of automotive spoiler.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.27 no.9
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• pp.1209-1219
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• 2003

The dynamic behaviors of the single vortex interacting with $CH_4-Air$ jet diffusion flame are investigated numerically. The numerical method is based on a predict-corrector scheme for a low Mach number flow. A two-step global reaction mechanism is adopted as a combustion model. Studies are conducted in fixed initial velocities for the three cases according as where $CO_2$ is added; (1) without dilution, (2) dilution in fuel stream and (3) dilution in oxidizer stream. A single vortex is generated by an axisymmetric jet, which is made by an impulse of a cold fuel when a flame is developed entirely in a computational domain. The simulation shows that $CO_2$ dilution in fuel stream results in somewhat larger vortex radius, and greater amount of entrainment of surrounding fluid than in other cases. Thus, the dilution of $CO_2$ in fuel stream enhances the mixing in single vortex and increases the stretching of the flame surface. The budgets of the vorticity transport equation are examined to reveal the mechanism of vortex formation when $CO_2$ is added. It is found that, in the case of $CO_2$ dilution in fuel stream, the vortex destruction due to volumetric expansion and the vortex production due to baroclinic torque are more dominant than in other cases.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.2 no.3
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• pp.166-176
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• 1990

Experimental study was made to find the effective ways for cooling of engine room in a power car through natural ventilation, forced ventilation and wind tunnel test of 1:10 model. Through the measurements of inner temperature of engine room and pressure distribution of model surface for the various opening combinations and the fan locations, the following results are obtained. For natural ventilation, side and top opening combination is more effective than the side openings only and optimal opening combination is all side openings with top center opening. For forced ventilation with fan on the roof, the combination of all sides and top opening is more effective than the combination of side and top opening, and the optimal location of fan is top center. When the model is located in the air stream, the combination of side and top opening is more effective than the side openings only, and the optimal location of top opening is the front opening. With both air stream and forced ventilation, the optimal location of fan is the side region, and the direction of side grill installation is found to have negligible effect on the room ventilation.

• Journal of ILASS-Korea
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• v.3 no.4
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• pp.43-49
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• 1998

In order to clarify the effect of equivalence ratio and kinds of fule in flame structure, a numerical simulation of triple flame developed in a co-flowing methane-air and air stream was carried out by the elementary chemical reaction mechanism. The following conclusions were obtained. Equivalence ratio at which the apparent burning velocity is maximum is a little larger than that of the one-dimensional premixed flame. Apparent burning velocities are two times higher than that of the one-dimensional premixed flame for the methane-air. The flame thrusts out forward in the downstream of the boundary between mixture and air stream, and a part of the flow is bent and forks out in this protruding flame so that a triple flame is originated; this triple flame is composed of fuel rich and lean premixed flame branches and a diffusion flame branch. Near the equivalence ratio at which the burning velocity of rule-dimensional premixed flame is the largest the effect of one-dimensional premixed flame becomes large and the fuel rich premixed flame advances and becomes vertical to the flow direction.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.5 no.1
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• pp.8-18
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• 2002

This research was conducted to establish the conservation strategy of stream water quality by analyzing the factors influenced on stream water quality in the northeastern part of Mt. Bughansan National Park from July 1998 to October 2001. The number of visitors resulted in the significant increase of electrical conductivity, which affected on pollution of the stream water quality. According to the multiple regression analysis, the pH of the stream water was related to dissolved oxygen and temperature of water at the 1% significant level. The electrical conductivity of the stream water was related to number of visitors, amount of $K^+$ and ${NO_3}^-$, total amount of ions, percentages of $Cl^-$ and $Na^+$ caused by solifluction soil at the 1% significant level. The anions($Cl^-$, ${NO_3}^-$ and ${SO_4}^{2-}$) of the stream water were related to number of visitors, electrical conductivity, air temperature, hardness, amount of ${NO_3}^-$, ${SO_4}^{2-}$, total ions, percentage of $Cl^-$, ${NO_3}^-$, ${SO_4}^{2-}$, amount of $Ca^{2+}$ caused by solifluction soil at the 1% significant level. To prevent the pollution of stream water in the northeastern part of Mt. Bughansan National Park, it is recommended that the number of visitors in the park should be managed and rehabilitated rapidly by measure to eco-friendly during the spring season.