• 상하수도학회지
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• 제22권3호
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• pp.351-358
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• 2008

The modified in-line mixer which was suggested in this study for small water treatment facilities was evaluated on the performance of coagulation. For the objectives of this research, computational fluid dynamics(CFD) simulation was applied for analysis of flow characteristics within the modified in-line mixer. For verifying the results of CFD simulation, wet tests for the pilot plant were conducted. The wet test was to measure the actual coagulant dispersion distribution on the overall cross-section at a distance of 5.5D from the chemical injection point. From the results of CFD simulation and wet test, it was shown that the coagulant dispersion within the modified in-line mixer was occurred more uniformly than within the existing PDM(Pump diffusion Mixer). The results have confirmed the modified in-line mixer had several advantages compared with the existing PDM in terms of dispersion efficiency.

• 한국산학기술학회논문지
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• 제19권10호
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• pp.437-443
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• 2018

본 연구에서는 라인믹서 내의 압력손실과 혼화성능에 대한 혼합요소의 영향을 해석하였다. 기체와 액체가 혼합된 고농도 오존수 장치는 단체급식시설의 살균 및 소독, 양식장의 수질관리 등 다양한 분야에서 사용되고 있다. 그러나 기존에 사용되는 장치는 가압방식을 사용하여 부피가 매우 크다. 최근에는 기후 변화로 강수량이 감소하여 지하수 및 지표수의 오염으로 음용수의 살균은 매우 중요하다. 따라서 기존의 장치와 대비하여 작은 공간을 사용하면서도 정수기능을 갖는 라인믹서형 기체-액체 혼합장치의 개발이 필요하다. 본 연구에서는 라인믹서 장치 내에 삽입한 혼합요소인 static mixer의 개수, 오리피스의 형태와 개수, 오리피스에 부착된 베인의 모양에 따른 유입유체의 혼화상태와 유동특성을 전산유체역학 모사를 통해 해석하고 혼화상태에 미치는 영향을 평가하였다. 곡면의 베인을 부착한 오리피스를 라인믹서에 사용한 경우 static mixer를 사용한 경우와 비교하여 비슷한 혼화정도를 나타내면서 압력손실양은 50% 이상 감소하는 것을 확인하였다.

• 상하수도학회지
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• 제22권6호
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• pp.689-696
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• 2008

In a water treatment process a complete and homogeneous dispersion of the coagulants in the raw water could be most important factor. This research was performed to evaluate coagulation performance of the in-line-orifice mixer which was recently introduced as a rapid mixing device. The test was to determine the actual coagulant dispersion distribution on the overall cross-section at a distance of 1.6~3D from the chemical injection point by measuring zeta potential. From the results of zeta potential test, it was shown that the coagulant dispersion within the in-line orifice mixer was occurred very unevenly. The results have confirmed that it is necessary to increase the velocity of coagulants injection or pressurized water rates, in order to reduce nonuniform distribution of chemicals.

• International Journal of Naval Architecture and Ocean Engineering
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• 제6권1호
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• pp.27-38
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• 2014

Flow mixing and pressure drop characteristics for marine selective catalytic reduction applications were investigated numerically to develop an efficient static mixer. Two different mixers, line- and swirl-type, were considered. The effect of vane angles on the relative intensity, uniformity index, and pressure drop was investigated in a swirl-type mixer; these parameters are dramatically affected by the mixer geometry. The presence of a mixer, regardless of the mixer type, led to an improvement of approximately 20% in the mixing performance behind the mixer in comparison to not having a mixer. In particular, there was a tradeoff relationship between the uniformity and the pressure drop. Considering the mixing performance and the pressure drop, the swirl-type mixer was more suitable than the line-type mixer in this study.

• 한국전자통신학회논문지
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• 제13권4호
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• pp.685-694
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• 2018

본 논문에서는 Ku대역 추적레이더의 핵심부품인 고주파 헤드 내 주파수 믹서(혼합기)의 설계 및 제작 결과에 대해서 다룬다. 단일종단(Single-Ended) 및 단일평형(Single-Balanced) 믹서의 단점을 보완하기 위해서, Fine-Line 구조의 평형(Balanced) 믹서를 설계하여 낮은 변환손실 특성을 가지도록 하였으며, Ku대역 RF신호를 입력받아 L밴드 IF신호를 생성하도록 하였다. 제작된 믹서에 대해서 Ku밴드 5개 샘플주파수를 대상으로 실험한 결과, 최대 잡음지수(Noise Figure Max) 6.823dB, 이득(Gain) 4.159dB ~ 4.676dB, 통과대역(Band Pass) 61MHz의 값을 확인하였다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집E
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• pp.777-782
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• 2001

In this study, we used In-line orifice mixer for efficient chemicals mixing in water treatment. The method of using In-line orifice mixer has been already proved the improvement of water treatment efficiency. Numerical study was performed using FLUENT, a commercial code, to standard design and production of effective In-line orifice mixer. As variable for exactly standardizing, a proper ratio between an outer diameter of cone and a diameter of pipe, a distance between cone and orifice, a determination of orifice diameter for an optimal mixing, a distance between injection nozzle's position and cone, Numerical study has been performed for optimal standard and analyzed flow field on a basis of turbulent intensity in an orifice downstream.

• Journal of information and communication convergence engineering
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• 제1권3호
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• pp.139-142
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• 2003

In this paper, we consider the factors that affect a conversion loss performance in designing a single balanced diode mixer integrated with IRF(Image Reject Filter), based on the embedded electrical wavelength placed between the IRF and mixer, diode matching and LO drive amplifier. To evaluate the conversion loss performance, we suggest two types of a single balanced mixer using 90 degree branch line coupler, microstrip line and schottky diode. One is only mixer and the other is integrated with IRF and LO drive amplifier. The measured results of a single balance diode mixer integrated IRF show the conversion loss of 8.5 dB and the flatness of 1 dB p-p from 21.2 GHz to 22.6 GHz with 10 dBm LO. The measured input PI dB and IIP3 are 7 dBm and 15 dBm respectively under the nominal LO power level of 10dBm. The LO/RF and LO/IF isolation are 22 dB and 50 dB, respectively.

• 상하수도학회지
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• 제23권1호
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• pp.107-112
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• 2009

This study was conducted for verification and systematization of estimation method about the headloss using CFD(Computational Fluid Dynamics). Head loss which happens between the inlet and outlet of in-line mixer can be a major factor for the design and construction. Also, this Case studies about the sensitivity related to the velocity in the piping system. As result, program's default calculation function was used to get each side's total pressure and the differential of each total pressure could be defined as head loss from in-line mixer. In the case of adopting pipe surface friction factor and geometry loss, Calculation residual can be much more reduced. It was found that residual of value between CFD method and field test ranged about 3 through 18 precent.

• 한국산학기술학회논문지
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• 제18권2호
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• pp.6-13
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• 2017

본 연구에서는 혼화기의 혼화성능과 압력손실을 개선하기 위해 오리피스의 형상과 개수에 따른 영향을 해석하였다. 물의 정수에서 중요한 과정은 물속의 이물질을 포집하는 응집 과정이고 응집제가 얼마나 물속에 고른 분포를 가지고 물속에 혼화되어 있는 지가 정수에 큰 영향을 미친다. 기계식 혼화방식이 갖는 정수과정에서의 긴 체류시간, 기계 소음, 과다한 에너지의 소비 및 높은 유지관리 비용 등의 단점을 보완하기 위해서 최근에는 응집제가 원수에 주입됨과 동시에 가능한 한 빠르게 수중에 확산시킬 수 있는 장치로서 관내혼화장치의 도입이 증가추세에 있다. 본 연구에서는 관내 혼화기의 혼화성능과 압력손실을 개선하기 위해 오리피스의 유무, 형상과 개수에 따른 약품의 체적분률, 관내 압력손실 등 유동특성과 체적분률이 수치해석에 의해 계산된다. 관내 혼화장치에 장착된 오리피스는 혼화정도를 향상시키나 압력손실이 증가되므로 오리피스의 개수를 제한하여야 한다. 주요 인자에 대한 민감도 분석을 통해 가이드 베인을 장착한 오리피스 1개를 사용하여 약품의 체적분률과 압력손실이 개선된 관내 혼화장치를 제안하였다.

• 한국분무공학회지
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• 제20권1호
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• pp.1-6
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• 2015

Visualization of the mixing pattern in a non-element mixer was carried out using laser induced fluorescence(LIF) to evaluate characteristics of mixer consisting of the main flow pipe and branch flow pipes. The branch flows were injected periodically with the period $T_{in}$ normal to the main flow, and rhodamine B was mixed into the most upstream branch flow to visualize mixing pattern in the main flow pipe by LIF. The length of boundary line L of the LIF image was measured. In this study, a numerical analysis was performed to identify the mixing process of the non-element mixer, and the results were compared with experimental results. Each result was almost the same. When the number of branch flows is increased, the mixing pattern became complicated and was supposed to become chaotic. The length of boundary line L increased exponentially with an increase in the number of branch flows.