• Journal of the Korean Society for Heat Treatment
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• v.36 no.1
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• pp.33-39
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• 2023

In this study, the effect of mixing condition of raw material powders possessing various particle size and particle size distribution on thermite reaction efficiency was investigated. When fine raw powders are used, rather the reaction yield tends to decrease due to agglomeration. In contrast, coarse raw powders make deteriorate the contact area between raw material powders containing Al reducing agent. To ensure the optimal thermite reaction efficiency, it is required to optimize a mixture condition of raw material powders prior to thermite reaction. From the current experiment, the maximum thermite reaction efficiency is 77%, which came from Nb₂O₅ + NiO +Al mixtures with size distribution from 9.25 to 22.63 ㎛.

• 한국전산유체공학회:학술대회논문집
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• 2005.10a
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• pp.45-47
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• 2005

We have investigated the mixing behavior of a tubular heat exchanger reactor using CFD and compared its mixing performance with different type of reactors such as jet mixer and continuous stirred tank reactor (CSTR). The mixedness in each reactor was quantified introducing a statistical average value, the coefficient of variation (CoV), which is a normalized standard deviation of concentration of a component over the whole fluid domain. Through the analysis of the flow pattern and turbulent energy distribution, we suggested a simple but effective way to improve the mixing performance of the tubular heat-exchanger reactor, which include the addition of the internals and/or the increase of the recycle flow rate. It was found that the CoV value of the tubular reactor could be nearly equivalent to that of CSTR by applying those two alternatives suggested here.

• Journal of Power System Engineering
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• v.1 no.1
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• pp.35-41
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• 1997

Annular jet pump can be used for the transportation of solid materials and fish. The effect of mixing chamber on the characteristics of annular jet pump is sought in this paper. Experiments were done for several reducing angles of mixing chamber, and for several throat area. Water was used for both the primary fluid and secondary fluid. A vortex was observed for the straight mixing chamber, but it was not observed for the mixing chamber whose reducing angle is $18^{\circ}$ or higher. The efficiency curves for the annular jet pump are presented in this paper, showing the annular jet pump which has 240 reducing angle and $0.611{\sim}0.73$ value of At/As. is most effective among the tested several annular jet pumps.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.229-230
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• 2009

This paper proposes a new design of ultra-slim color mixing lens (CML) for backlight unit (BLU), and presents simulated performance of the design. The novel color mixing structure has a shorter mixing length (< 1cm) than the existing color mixing structure, and achieves high efficiency and uniformity.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• v.y2005m4
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• pp.368-373
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• 2005

To achieve efficient combustion within a manageable length, a successful fuel injection scheme must provide rapid mixing between the fuel and airstreams. The aim of the present numerical research is to investigate the mixing enhancement combustion phenomena according to fuel injector location near the cavity in supersonic flow. Fuel injector location changes the actual length to depth ratio of the cavity in the supersonic combustor. Therefore fuel injector location near the cavity effects different fuel/air mixing efficiency and combustion efficiency.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2002.04a
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• pp.209-212
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• 2002

Main radionuclides of the soil waste stored in Korea Atomic Energy Research Institute are Co-60 and Cs-137. Moisture content of soil is 12%, pH of soil is 5.8, and content of organic matter is 2.2 %. Radioactive concentrations of the soil particle size of which is less than 0.063mm and soil in the drum surface of which is more than radiation dose rate 0.05mR/hr are higher. Meanwhile, radioactive concentration of soil in the drum surface of which is less than radiation dose rate 0.02 mR/hr are mostly lower. On using the mixing solution of ammonium sulfate and citric acid, 62% Co was removed from soil and 41% Cs was removed. Also, on using the mixing solution of ammonium nitrate and citric acid, 61% Co was removed from soil and 39% Cs was removed, and on using the mixing solution of ammonium potassium oxalate, 36% Co was removed and only 3% Cs was removed. And on using only water, removal efficiency is less than 5%.

• Journal of the Korea Institute of Military Science and Technology
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• v.6 no.4
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• pp.113-123
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• 2003

Both numerical analysis and experiment of cold and hot tests were performed to obtain basic design data for the swirl coaxial type Injector and to predict the combustion performance. Mass distribution, mixing distribution, mixing efficiency, characteristic velocity efficiency were measured by the cold tests and numerical analysis using the commercial thermo-hydraulic program. Test and analysis variables were recess, pressure drop, velocity ratio, mixing spray, mixture ratio. Hot tests were performed for the Uni-element injector to compare the performance with the cold test results, and, hot tests for Multi-element injector were performed to compare the performance with Uni-element injector. Designed thrust of the Uni-element injector liquid rocket was 35kgf at sea level and combustion chamber pressure, 20bar. Kerosene and Lox were used as a propellant.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.11a
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• pp.156-157
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• 2021

Since concrete is contaminated or radioactive during operation of nuclear power plants, it is the most important radioactive waste generated during the dismantling of a nuclear power plant. The amount of waste is different depending on the pollution state of each facility and the applied technology is different, so there is a big difference. We aim to reduce the amount of waste and increase the value of recyclability through technology to remove radionuclides attached to the surface. For this purpose, laser scabbling, which exfoliates the surface of concrete by irradiating a laser, and a facility system for controlling dust and dust are used in parallel. The purpose of this study is to evaluate the efficiency of laser scabbling by manufacturing simulated concrete for nuclear facilities, and to review the optimal mixing design conditions for nuclear facility structures.

• Journal of Korean Society of Water and Wastewater
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• v.20 no.4
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• pp.559-571
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• 2006

The overall objective of this research was to find out the interrelation of coagulant and organic matter during rapid mixing process and to identify the change of organic matter by mixing condition and to evaluate the effect of coagulation pH. During the coagulation, substantial changes in dissolved organics must be occurred by coagulation due to the simultaneous formation of microflocs and NOM precipitates. Increase in the organic removal efficiency should be mainly caused by the removal of microflocs formed during coagulant injection. That is, during the mixing period, substantial amount of dissolved organics were transformed into microflocs due to the simultaneous formation of microflocs and NOM precipitates. The results also showed that 40 to 80% of dissolved organic matter was converted into particulate material after rapid mixing process of coagulation. During the rapid mixing period, for purewater, formation of dissolved Al(III) (monomer and polymer) constant by rapid mixing condition, but for raw water, the species of Al hydrolysis showed different result. During the rapid mixing period, for high coagulant dose, Al-ferron reaction increases rapidly. At A/D(Adsorption and Destabilization) and sweep condition, both $Al(OH)_3(s)$ and dissolved Al(III) (monomer and polymer) exist, concurrent reactions by both mechanism appear to cause simultaneous precipitation.

• Proceedings of the KSME Conference
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• 2005.11a
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• pp.52.1-52.1
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• 2005