• 전기학회논문지P
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• 제51권3호
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• pp.132-136
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• 2002

In this study, we analyzed the luminous efficiencies of Ne-Xe-Ar and He-Ne-Xe-Ar mixing gas in compared with those of Ne-Xe and He-Ne-Xe mixing gas to improve luminous efficiency by adding a small amount of Ar gas. At the Xe 4%, the brightness of Ne-Xe and He-Ne-Xe mixing gas is higher than others. As the Xe % increases, power consumption decreases. Thus, in the Ne-Xe and He-Ne-Xe mixing gas of Xe 4%, we obtained maxium luminous efficiency. The Ar concentration is varied from 0.1% to 0.7% in this study. The luminous efficiency of the Ne-Xe(4%) mixing gas is improved to 1.16 and 1.13 lm/W by adding an Ar concentration of 0.4% and 0.5%, respectively. The luminous efficiency of the He-Ne-Xe(4%) (He : Ne = 7 : 3) mixing gas is considerably improved by adding an Ar concentration of above 0.3%. The maximum luminous efficiency of this mixing gas is 1.38 lm/W at the condition of adding an Ar concentration of 0.5%.

• 한국정밀공학회지
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• 제33권1호
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• pp.31-35
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• 2016

For reaction injection molding (RIM) polyurethane was mixed in the mixing head by impingement mixing, injected into the mold, and cured quickly, as soon as the mold is filled. The shape of the nozzle in the mixing head is critical to improve the quality of polyurethane. To achieve homogeneous mixing, an intensive turbulence energy in the mixing nozzle is essential. In this study, a mixing nozzle for RIM was designed, and mixing efficiency was investigated based on experiment. Experiments were conducted with different combinations of nozzle tips and exit diameter to measure the mixing efficiency by measuring jet force and investigating mixing image with high speed camera. Jet force increased gradually and reaches steady state conditions. The jet force depended on shape of nozzle tip and outlet sizes. These results suggest that optimized nozzle configurations are necessary for high efficiency mixing with RIM.

• 한국추진공학회지
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• 제3권3호
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• pp.1-8
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• 1999

$H_2$O/Kerosene을 사용하여 Unlike 충돌형 인젝터(FOOF형)에서 산화제와 연료의 운동량비 변화에 따른 혼합효율을 측정하였다. 모의 추진제의 운동량비 1.5(총혼합비 1.89)에서 혼합성능은 최대 값을 나타내었으며 모의 추진제의 실험결과는 실제 추진제인 LOX/Kerosene에 적용하여 혼합특성속도 효율을 예측하였다 연구 결과 혼합특성속도 효율은 운동량비 2.0에서 최대 값을 나타내었다. 이러한 예측은 실제 연소실험을 통하여 얻어진 연소효율과 약간의 차이는 있으나 초기설계자료로서 충분한 가치가 있는 것으로 판단된다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.3139-3143
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• 2007

The objective of this paper was to investigate the mixing characteristics of an three-stage inline coagulant mixing system experimentally. Wastewater samples of pH 8.5 and initial turbidity 1,000NTU were taken from a site of tunneling work. At the constant dosage, 0.36mL/L, of polymer as coagulant aids, the coagulation efficiency with the dosage of PAC as coagulant was about 4${\sim}$6% at 10 minutes after sampling. In the case of 2 different velocity gradient conditions, the efficiency of turbidity removal was increased about 6.5${\sim}$8% with increasing the dosage of coagulant while, the efficiency was increased about 20${\sim}$21.5% with increasing the dosage of coagulant aids. The efficiency of turbidity removal with the settling time after sampling was about 90% after 1 minute, and the efficiency was about 95% after 5 minutes.

• 설비공학논문집
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• 제18권12호
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• pp.999-1006
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• 2006

A study of temperature profiles in mixing zone of AHU (air handling unit) can contribute greatly to enhance performance of AHU system, so the study on the temperature distribution between RA (return air) and OA (outdoor air) is important to analyze the mixing characteristics in a mixing zone of AHU. Accordingly, the temperature profiles during RA (return air) and OA (outdoor air) supply process into mixing zone of AHU with an air mixer are studied experimentally. The effect of air mixer, OA temperature and RA/OA flow rate are studied in detail. In this study, the results show that the mixing efficiency is all high for installed the air mixer. The more OA temperature increase and OA flow rate decrease, the more mixing efficiency is high.

• 한국환경보건학회지
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• 제26권4호
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• pp.129-133
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• 2000

The objective of this study was to invetigate the coagulation effects of landfill leachate by using Acid Mine Drainage(AND). The coagulation efficiency was investigated by mixing landfill leachate with F $e^{+3}$ solution earned by oxidation of pyrite(AMD). In the results of this experiment, it was found that the amount of removed COD and SS was approximately 30% respectively by mixing at the ratio of AMD three to leachate one. And it showed highest turbidity removal efficiency at all mixing ratio. Concentration of Fe was decreased with increasing mixing ratio, however it was increased inversely at mixing ratio 4. Optimal mixing ratio was 3 at the results obtained by leachate coagulation experiments. Also removal efficiency at mixing ratio 3 corresponded to 500mg/$\ell$ of FeC $l_3$ dosage. it was suggested that pretreatment by mixing of AMD and leachate remove both suspended organic material of leachate and metal of AMD.

• 한국분무공학회지
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• 제11권4호
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• pp.220-227
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• 2006

Experimental studies has been conducted to investigate the effect of orifice diameter ratio on the mixing characteristics of the split element of doublet and triplet elements. The spray characteristics of non-reacting immiscible liquids have been investigated using a patternator. The local volume fraction is measured by use of mean value of each component. This volume measurement represents the mixing characteristics of the liquid, which affect the overall combustion efficiency. The ratio of the orifice diameter, ranging from 1 to 1.5, and that of the jet-momentum, ranging from 0.5 to 6.0, we used. The jet impinging behavior with use of various ratios exhibits substantially different mixing characteristics. Mixing efficiency is maximized when the jet-momentum ratio is increased; this behavior is particularly prominent when the orifice diameter ratio is greater than unity. The split of the triplet element yields better mixing characteristics and is more effective than that of the doublet element in regard to achieving high combustion efficiency. The optimum mixing factor for the triplet element is found to be 0.75, according to our measurement.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2002년도 학술대회지
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• pp.283-286
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• 2002

The mixing of fuel and oxidizer and each mass distribution of unlike split triplet(F-O-O-F) injector for liquid rocket which are known to affect the combustion efficiency significantly, has been investigated using PLLIF technique. Experiment is conducted to investigate the effect of mixture ratio(MiR), momentum ratio(MoR) and impinging angle on mixing efficiency. The mixing efficiency, which is introduced by Rupe, gives the global chracteristic of spray mixing. Experiment far comparison with triplet injector(F-O-F), which has same momentum ratio and impinging angle with split triplet injector is conducted.

• 한국정밀공학회지
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• 제25권6호
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• pp.143-149
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• 2008

This paper presents the results of the study on the novel micro mixer. Existing micro mixer is classified as active mixing and passive mixing by the mixing principles. Both mixing principles have problems. For solving these problems, this research has developed the novel micro mixers based on a totally different principle compared with former mixers. They not only have a simpler structure than former ones but also are able to achieve high mixing efficiency in spite of low power consumption due to using Lorentz Force. In addition, they are designed to increase the efficiency of mixing by changing the rotating direction of fluid with a polar switching circuit. Driving forces of the mixer are Lorentz force and a moving force of fluid due to electrophoresis. Because the efficiency of mixer is affected by electrode shape, several models have been made. The computer simulation has been made to estimate the efficiency of each mixer.

• 대한기계학회논문집B
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• 제29권12호
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• pp.1369-1376
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• 2005

Effective mixing gives strong advantageous impact on microfluidic applications since mixing is in general very slow process motivated by molecular diffusion transport only on the micro-scale. In this work, the mixing characteristics are analyzed in a Y-channel micromixer with obstacles. For the through analysis, our laboratory in-house unstructured grid CFD code is validated through solving a concentration transport in a uniform microchannel. The solutions well correspond to both exact solutions and those from MemCFD. Mixing in a Y-channel micromixer with obstacles is numerically investigated by the in-house code to search the optimal radius and layout of obstacles. From the simulations, the mixing efficiency appears to be proportional to the magnitude of the formation of lateral velocity component. It is also shown that the asymmetric layout and radius enlargement of obstacles greatly improves mixing efficiency.