• 동력기계공학회지
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• 제1권1호
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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.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2006년도 춘계 학술발표회 논문집
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• pp.1155-1158
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• 2006

This paper presents a study on the construction condition and environmental effect of deep soil mixing. Construction condition means the difference in unconfined compressive strength with respect to the depth and location of samples. Environmental effect means alkalinity diffused from soil stabilizer. The experimental results indicate that the unconfined compressive strength vary with respect to the depth, and doesn't show consistency pattern. So, in field application we must decide a mixing ratio enough to satisfy the least unconfined compressive strength. The difference in unconfined compressive strength with respect to the location of samples is negligible. The generation of alkalinity from soil stabilizer is reduced by permeating in non-improved soil and it is expected that the diffusion of alkalinity has no environmental effect on soil and ground water.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2014년도 제49회 KOSCO SYMPOSIUM 초록집
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• pp.285-288
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• 2014

Experiments have been performed for the burners used in the non-oxidizing direct fired furnaces for the cold rolled plate to investigate the effect of fuel/air mixing patterns of the burner nozzle on flame shape, temperature and combustion gas concentration. CFD simulation has also been performed to investigate the mixing state of air-fuel for a nozzle mixing burner and a partially pre-mixing burner. A partially pre-mixing burner showed that flame temperature increased up to $26^{\circ}C$ on average compared than that of the nozzle mixing. It also showed that the mixing distance is important at the partially pre-mixing burner. Test results for a partially pre-mixing burner showed that the residual oxygen concentration and the volume ratio of $CO/CO_2$ of the flame were applicable to be used in field furnaces.

• Nuclear Engineering and Technology
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• 제55권10호
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• pp.3775-3786
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• 2023

Mixing Vane Grid (MVG) is one of the most important structures in fuel assembly due to its high performance in mixing the coolant and ultimately increasing Critical Heat Flux (CHF), which avoids the temperature rising suddenly of fuel rods. To evaluate the mixing performance of the MVG, a Total Diffusion Coefficient (TDC) mixing coefficient is defined in the subchannel analysis code. Conventionally, the TDC of the spacer grid is obtained from the combination of experiments and subchannel analysis. However, the processing of obtaining and determine a reasonable TDC is much challenging, it is affected by boundary conditions and MVG geometries. In is difficult to perform all the large and costing rod bundle tests. In this paper, the CFD method was applied in TDC analysis. A typical 5 × 5 MVG was simulated and validated to estimate the mixing performance of the MVG. The subchannel code was used to calculate the TDC. Firstly, the CFD method was validated from the aspect of pressure drop and lateral temperature distribution in the subchannels. Then the effect of boundary conditions including the inlet temperature, inlet velocities, heat flux ratio between hot and cold rods and the arrangement of hot and cold rods on MVG mixing and TDC were studied. The geometric effects on mixing are also carried out in this paper. The effect of vane pattern on mixing was investigated to determine which one is the best to represent the grid's mixing performance.

• 대한의생명과학회지
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• 제1권1호
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• pp.73-79
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• 1995

자동혈구분석기(Technicon $H^*2$ )에 의한 혈액검체의 측정전 mixing횟수가 검사결과에 미치는 영향을 평가하기 위하여 19가지 parameter를 대상으로 초기측정치에 대한 반복측정치의 변화율을 종속변수로 하여 단순회귀분석을 실시하였다. Mixing횟수가 증가할수록 RBC, Hct, MCV는 통계적으로 유의하게 (p< .01)감소하였고, 호염기구 백분율은 유의하게(p< .05)증가하였으므로 평가된 19가지 parameter의 21%인 4가지 검사항목에서 변화가 있었다.

• Environmental Engineering Research
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• 제15권2호
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• pp.57-62
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• 2010

The purpose of this study was to investigate the effect of mixing methods on the biodegradation of sorbed naphthalene and phenanthrene in soils. Biodegradation was initiated by inoculating Pseudomonas sp. KM1 into equilibrated soil slurry vials. Four different mixing methods, including no mixing, orbital shaking, rolling and rotating were utilized to enhance the biodegradation of both naphthalene and phenanthrene. The experimental results showed that the sorbed compounds were more effectively biodegraded with rolling and rotating mixing methods. The sorbed naphthalene concentrations were reduced to 0 mg/kg via the rolling and rotating methods. However, with no mixing and the orbital shaking methods, the sorbed naphthalene concentrations were comparatively high, ranging from 2.59 to 20.45 mg/kg. Similar trends were observed for the biodegradation of phenanthrene, but the concentrations remaining were higher than those of naphthalene, due to the limited bioavailability of the sorbed phenanthrene. The rolling and rotating mixing methods are suggested can distribute bacteria uniformly in the slurry system; improve the mass transfer rate and the probability of physical contact between bacteria and the sorbed contaminants, resulting in higher bioavailability of the contaminants.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 춘계학술대회
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• pp.1819-1824
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• 2004

The common method to improve heat transfer in Nuclear fuel rod bundle is install a mixing vane in space grid. The previous split mixing vane is guides cooling water to swirl flow in sub-channel of fuel assembly. But, this swirl flow decade rapidly after mixing vane and the effect of enhancing the heat transfer vanish behind this short region. The large scale secondary vortex flow was generated by rearranging the inclined angle direction of mixing vanes to the coordinated directions. This LSVF mixing vanes generate the most strong secondary flow vortices which maintain about 35 $D_H$ after the spacer grid and the streamwise vorticity in subchannel with LSVF mixing vane sustain two times more than that in subchannel with split mixing vane. The turbulent kinetic energy and the Reynolds stresses generated by the mixing vanes have nearly same scales but maintain twice more than previous type.

• 유기물자원화
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• 제3권2호
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• pp.47-57
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• 1995

본 연구의 목적은 유기성폐기물 퇴비화시 교반강도가 퇴비화공정에 미치는 영향을 알아보기 위한 것이다. 주된 연구지표는 교반강도와 초기수분함량이었다. 본 연구를 위하여 기계식 교반장치를 갖춘 실험실규모의 퇴비화반응조가 이용되었다. 실험대상폐기물은 생분뇨슬러지와 감압증발처리공정을 거친 분뇨슬러지, 그리고 돈분을 이용하였다. 초기수분함량이 60%와 63% 인 경우 연속교반시 간헐교반보다 유기물분해율이 더 높게 나타났다. 또한 시료의 물리적 성상도 연속교반이 간헐교반보다 더 균등질의 양호한 상태를 나타내었다. 한편 초기 수분함량 68%인 경우는 혼합되기 보다는 시료 일부가 반죽상태를 형성하는 문제가 발생하였으며 유기물분해율도 연속교반의 경우가 간헐교반보다 더 낮게 나타났다.

• 한국연소학회지
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• 제18권2호
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• pp.8-16
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• 2013

The flameless combustion has been considered as one of the promising combustion technology for high thermal efficiency, reducing NOx and CO emissions. In this paper, the effect of air and fuel injection condition on formation of flameless combustion was analyzed using three dimensional numerical simulation. The results show that the high temperature region and the average temperature was decreased due to increase of recirculation ratio when air velocity is increased. The average temperature was also affected by entrainment length. Generally mixing effect was enhanced at low entrainment length and dilution was dominated at high entrainment length. This entrainment length was greatly affected by air and fuel injection velocity and distance between air and fuel. It is also found that the recirculation ratio and dilution effect were generally increased by entrainment length and the recirculation ratio, mixing and dilution effect are the significant factor for design of flameless combustion system.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2005년도 춘계 학술대회논문집
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• pp.1-13
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• 2005

Fluid flows within microchannels are characterized by low Reynolds numbers. Therefore the effect of mixing is a crucial factor in design of the channels. Since the action of the electro-osmotic or magnetic forces used in the mixing enhancement is usually periodic in the three-dimensional channel configuration, use of the various concepts of chaotic advection is reasonable in the quantification of the stirring effect. In this paper, the details of the method of material-stretching mapping is explained. The actual application of the method to the screw extruder is also presented.