• 상하수도학회지
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• 제22권3호
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• pp.281-288
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• 2008

Cake resistance is influenced by floc size deposited on membrane surface. Enlarging floc size can reduce cake resistance. The small particles are enlarged by coagulation and flocculation process in conventional mixing tank at membrane filtration system. Fully-grown flocs for reducing the cake resistance, however, are ruptured while passing through a pump. In light of this fact, this study aims to experimentally look at the reaggregation phenomenon of mixing system. In addition, reaggregation phenomenon of mixing system is compared with first-aggregation of in-line injection system in which coagulant is injected just before a pump. These results suggest that first-aggregation of in-line injection system is better than reaggregation of mixing system for G-value above $3100sec^{-1}$. Since G-value in pipe of actual membrane filtration system are usually larger than $3100sec^{-1}$. The performance of in-line injection system is expected to be better than the conventional mixing tank system.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2009년도 제33회 추계학술대회논문집
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• pp.202-206
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• 2009

고속회전 연료분사시스템의 분무특성을 연구하였다. 분무특성에 영향을 주는 직렬식 분무오리피스의 직경을 각각 1mm, 2mm, 3mm, 4mm, 5mm와 분무오리피스 수를 3개, 6개, 12개로 변화시켜가며 분무특성 연구를 수행하였다. PDPA 측정 시스템을 이용하여 분무입자의 크기와 속도, 분무분포 등을 측정하였고, 고속카메라를 이용하여 분무가시화를 수행하였다. 실험결과, 분무오리피스로부터 분출된 단일 액주의 길이는 회전속도에 의해 제어되며, 분무입자의 크기(SMD)는 분무오리피스의 직경과 수가 증가함에 따라 작아지는 경향을 보였다. 결국 분무입자의 크기를 제어하는 기본 메커니즘은 분무 오리피스내의 액막의 두께에 의해 결정됨을 알 수 있었다.

• Bulletin of the Korean Chemical Society
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• 제31권9호
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• pp.2637-2643
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• 2010

In order to develop a new line injection system for spin draw yarn (FD SDY) fibers, the effect of various parameters in extrusion and melt line conditions on the dispersion and distribution of $TiO_2$ particles within FD PET fibers was investigated. As a result, the dispersibility of $TiO_2$ particles in a PET matrix is found to depend on the particle size and its surface characteristics. Surface modification of $TiO_2$ by dimethyl polysiloxane resulted in the improved dispersibility and affinity of $TiO_2$ particles in the PET matrix. Especially, residence time, mixing temperature, and mixing shear rate in the new line injection system under the SDY spinning process were very important parameters to minimize the agglomeration of $TiO_2$ particles. The FD SDY prepared by the new line injection system was superior to those using the polymerization process and the conventional masterbatch chip dosing process in the color-L and color-b values of the fibers.

• 한국유체기계학회 논문집
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• 제19권5호
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• pp.50-60
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• 2016

A design methodology of the modeled test facility to conserve an injection performance of a passive safety injection system is proposed. This safety injection system is composed of a core makeup tank and a safety injection tank. Individual tanks are connected with pressure balance line on the top side and injection line on the bottom side. It is important to conserve the scaled initial injection flow rate and total injection time since this system can be operated by small gravity head without any active pumps. Differential pressure distribution of the injection line induced by the gravity head is determined by the vertical length and elevation of each tank. However, the total injection time is adjustable by the flow resistance coefficient of the injection line. The scaling methodology for the tank and flow resistance coefficient is suggested. A key point of this test facility design is a scaling analysis for the flow resistance coefficient. The scaling analysis proposed on this paper is based on the volume scaling law with the same vertical length to the prototype and can be extended to a model with a reduced vertical length. A set of passive injection test were performed for the tanks with the same volume and the different length. The test results on the initial flow rate and total injection time showed the almost same injection characteristics and they were in good agreement with the design values.

• KSBB Journal
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• 제16권5호
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• pp.459-465
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• 2001

본 연구에서는 생물공정에서 주요 기질로 이용되는 글루코오스와 전분을 온라인 모니터링 하기 이하여 GOD, AMG를 이용한 흐름 주입분석(Flow Injection Analysis : FIA) 기술을 개발하였고, 효소활성 변화를 비교, 고찰하였다. 특히, epoxy 고분자 담체에 고정화된 COD-FIA와 AMG/GOD-FIA 장치의 성능을 조사하였고, FIA의 조작온도, pH, 운반용액의 첨가제, 염 그리고 각종 신진대사물질의 고정화된 GOD, AMG의 활성에 대한 영향을 소형 반응기내 글루코오스와 전분의 농도 변화를 온라인 모니터링하였다. GOD-FIA에 의한 온라인 모니터링 결과는 오프라인 분석과 비교적 잘 일치하였으며, AMG/GOD-FIA에의한 전분 농도의 온라인 모니터링은 단일 효소 반응기를 사용한 경우 두 개의 효소 반응기를 사용한 경우보다 더 효과적임을 알 수 있었다.

• Nuclear Engineering and Technology
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• 제49권5호
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• pp.968-978
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• 2017

Three small-break loss-of-coolant accident (SBLOCA) tests with safety injection pumps were carried out using the integral-effect test loop for SMART (System-integrated Modular Advanced ReacTor), i.e., the SMART-ITL facility. The types of break are a safety injection system line break, shutdown cooling system line break, and pressurizer safety valve line break. The thermal-hydraulic phenomena show a traditional behavior to decrease the temperature and pressure whereas the local phenomena are slightly different during the early stage of the transient after a break simulation. A safety injection using a high-pressure pump effectively cools down and recovers the inventory of a reactor coolant system. The global trends show reproducible results for an SBLOCA scenario with three different break locations. It was confirmed that the safety injection system is robustly safe enough to protect from a core uncovery.

• 동력기계공학회지
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• 제1권1호
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• pp.42-51
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• 1997

In this study, in order to investigate the influence of cam profile on the injection rate, the characteristics of injection in PLN (pump - line - nozzle) diesel injection system were simulated. Six types of the profile of fuel cam were used for simulation. The maximum injection pressure and maximum injection rate of initial and end phase were analyzed to demonstrate the characteristics of injection. The mathematical model of the injection system and the computation results were verified by experimental results. Simulation results showed that the maximum injection pressure, maximum injection rate, injection quantity and pressure drop in the end phase were proportional to the velocity of fuel cam during the effective stroke.

• KSBB Journal
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• 제17권4호
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• pp.339-344
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• 2002

Flow injection analysis technique for monitoring of xylitol concentrations in biological processes has been developed using xylitol oxidase (XYO) immobilized on VA-Epoxy Biosynth carrier. The immobilized XYO cartridge has been integrated into a FIA system with an oxygen electrode and systematically investigated with regards to the factors which can affect the activity of the immobilized XYO, such as pH, temperature, salt concentration etc. The activity of the immobilized XYO increased with the temperature ($19.0 - 29.0^{circ}C$) and sample injection volume ($75-250\muL$) and molarity of potassium phosphate buffer (0.1-1 M), but it reached the highest value at pH 8.5. The XYO-FIA system has been also applied for on-line monitoring of xylitol concentrations in a reactor and showed good operational stability and agreement with off-line data measured with HPLC.

• Current Applied Physics
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• 제18권11호
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• pp.1451-1457
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• 2018

Injection compression molding (ICM) is an advantageous processing method for producing thin and large polymeric parts in a robust manner. In the current study, we employed the ICM process for an energy-related application, i.e., thin and large polymeric battery case. A mold for manufacturing the battery case was fabricated using injection molding. The filling behavior of molten polymer in the mold cavity was investigated experimentally. To provide an in-depth understanding of the ICM process, ICM and normal injection molding processes were compared numerically. It was found that the ICM had a relatively low filling pressure, which resulted in reduced shrinkage and warpage of the final products. Effect of the parting line gap on the ICM characteristics, such as filling pressure, clamping force, filling time, volumetric shrinkage, and warpage, was analyzed via numerical simulation. The smaller gap in the ICM parting line led to the better dimensional stability in the finished product. The ICM sample using a 0.1 mm gap showed a 76% reduction in the dimensional deflection compared with the normal injection molded part.

• KSBB Journal
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• 제13권3호
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• pp.244-250
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• 1998

글루코스와 초산을 온라인 모니터링 하기위한 흐름주입분석기 술이 개발되었고 대장균발효공정에 이용되었다. 또한, Epoxy 고 분자 담체에 고정화된 GOD와 SOD 를 이용한 GOD-FIA와 SOD-FlA의 특성을 연구했다. 즉, FIA 의 조작온도, 운반용액 속의 첨 가제 (Triton, EDTA, natrium azid 등), 분석 시 료에 용 해된 신진대사물의 농도, pH, 초산측정시 사코진 농도 등에 따 라 고정화된 GOD와 SOD의 활성도, 즉 검출신호의 높이변화를 고찰했다. 최소배양액 과 복합배양액을 사용한 대장균 발효공정 에서 달루코스와 초산을 동시에 온라인 모니터링 하였으며 그결 과는 오프라인 분석결과와 잘 일치 하였다,