• Title/Summary/Keyword: Venturi

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Architecture and Language: Theories and Practice in Architecture since the 1960s. (건축과 언어: 1960년대 이후 서구건축의 이론과 실험)

  • 김성홍
    • Lingua Humanitatis
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    • v.1 no.2
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    • pp.107-121
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    • 2001
  • This paper examines the way in which the idea of language has been introduced in architectural discourse since the late 1960s. The paper reviews the works of Robert Venturi, Charles Jencks, Peter Eisenman, Alan Colquhoun, and Mario Gandelsonas, which explore the analogy between linguistic and architectural form. All of the writers above are responsive to each other's theoretical positions, sometimes implicitly and sometimes explicitly. A system of signs can be approached by asking how the lexicon and syntax are proportioned. The same question may be posed to architecture: can architecture be understood as a lexicon or as a relational structure, such as language is\ulcorner Two perspectives are presented by architectural theorists. The first advocated by Venturi and Jencks posit architectural form as a problem of signs. The problem with this perspective is that, it reduces architecture into popularized iconography in favor of the representational aspects of architectural form. The second perspective, developed by Eisenman, explores the possibility of finding new formal constructs in the abstract relationship of formal properties. Eisenman's theory, however, has its own problems for, in highlighting syntactic structure, it minimizes the distinction between the perceptual and the pragmatic dimensions. Yet both perspectives address crucial problems of contemporary architecture and expand architectural discourse into the broader realm of humanistic studies.

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The Methods to Improve the In-Line Eductor (포소화약제 혼합장치의 개량화 방안)

  • Joo, Seung-Ho;Lim, Mann-Taek;Kim, Hye-Won;Kong, Ha-Sung
    • Journal of the Korea Safety Management & Science
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    • v.13 no.2
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    • pp.275-282
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    • 2011
  • A core device of foam system is the in-line eductor and it is the device to mix the foam liquid into liquid solution proper to the use density and the mixture ratio must be kept regularly regardless of changing fluid condition of the front and rear end of the in-line eductor. However, if the flux of the pressurized water changes, the mixture ratio is not kept regularly, and so it becomes a cause which a performance of fire-extinguishing deteriorates in discharging foam liquid. I devise a method to improve it that the metering orifice type in-line eductor is improved into the metering venturi type in-line eductor, the fluctuation of the mixture ratio to the flux change of the pressurized water is minimized and the performance of fire-extinguishing is kept regularly. As this method is simple in its structure and can be designed at a low cost, it helps for maintenance as well. In the future, it seems to need the research for the metering nozzle type in-line eductor in the future.

A SOFT-SENSING MODEL FOR FEEDWATER FLOW RATE USING FUZZY SUPPORT VECTOR REGRESSION

  • Na, Man-Gyun;Yang, Heon-Young;Lim, Dong-Hyuk
    • Nuclear Engineering and Technology
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    • v.40 no.1
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    • pp.69-76
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    • 2008
  • Most pressurized water reactors use Venturi flow meters to measure the feedwater flow rate. However, fouling phenomena, which allow corrosion products to accumulate and increase the differential pressure across the Venturi flow meter, can result in an overestimation of the flow rate. In this study, a soft-sensing model based on fuzzy support vector regression was developed to enable accurate on-line prediction of the feedwater flow rate. The available data was divided into two groups by fuzzy c means clustering in order to reduce the training time. The data for training the soft-sensing model was selected from each data group with the aid of a subtractive clustering scheme because informative data increases the learning effect. The proposed soft-sensing model was confirmed with the real plant data of Yonggwang Nuclear Power Plant Unit 3. The root mean square error and relative maximum error of the model were quite small. Hence, this model can be used to validate and monitor existing hardware feedwater flow meters.

Numerical Analysis of Flow Uniformity in Selective Catalytic Reduction (SCR) Process Using Computational Fluid Dynamics (CFD)

  • Shon, Byung-Hyun
    • International Journal of Advanced Culture Technology
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    • v.10 no.3
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    • pp.295-306
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    • 2022
  • The NOx removal performance of the SCR process depends on various factors such as catalytic factors (catalyst composition, shape, space velocity, etc.), temperature and flow rate distribution of the exhaust gas. Among them, the uniformity of the flow flowing into the catalyst bed plays the most important role. In this study, the flow characteristics in the SCR reactor in the design stage were simulated using a three-dimensional numerical analysis technique to confirm the uniformity of the airflow. Due to the limitation of the installation space, the shape of the inlet duct was compared with the two types of inlet duct shape because there were many curved sections of the inlet duct and the duct size margin was not large. The effect of inlet duct shape, guide vane or mixer installation, and venturi shape change on SCR reactor internal flow, airflow uniformity, and space utilization rate of ammonia concentration were studied. It was found that the uniformity of the airflow reaching the catalyst layer was greatly improved when an inlet duct with a shape that could suppress drift was applied and guide vanes were installed in the curved part of the inlet duct to properly distribute the process gas. In addition, the space utilization rate was greatly improved when the duct at the rear of the nozzle was applied as a venturi type rather than a mixer for uniform distribution of ammonia gas.

A Numerical Study on an Optimum Design of a Hybrid Collector Coupled with the Principle of Cyclone, Baffle and Bag-Filter (싸이클론과 배플 및 백필터 원리를 결합한 하이브리드형 집진기의 최적화 설계를 위한 수치해석)

  • Hong, Sung-Gil;Jung, Yu-Jin;Lim, Ki-Hyuk;Yoo, Jeong-Kun;Shon, Byung-Hyun
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.14 no.2
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    • pp.983-989
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    • 2013
  • The current research reviewed the design conditions that would maximize the efficiency of the hybrid collector that combines in one unit "cyclone-inertial impaction-bag filter". The computational analysis for the shape of cyclone entry predicts that a design that installs the guide vane at the entry of the tangential type cyclone brings a high-rpm and powerful vortex, very effective in promoting the deflection of coarse particles from the streamline at the cyclone. As the lower part of the cyclone is venturi-shaped, however, a strong flow downward of 4 to 5 m/sec persists through the lower part of the hopper, revealing the likely reentrainment of collected dust. And the removal of the venturi at the lower part of the cyclone would solve the problem of the reentrainment of collected dust. The acceleration of the flow velocity through the adjustment of the gap of the collision baffle would increase the effect of collision, but as the interference with the dust separation is expected, the original design should be kept for the baffle.

Characteristics of Proteins and Total Suspended Solids Removal by Counter Current Air Driven Type, High Speed Aeration Type and Venturi Type Foam Separator in Aquacultural Water (향류 공기 구동식, 고속 폭기식 및 벤튜리식 포말분리기에 의한 양어장수의 단백질 및 부유 고형물의 제거 특성)

  • SUH Kuen-Hack;KIM Byong-Jin;KIM Sung-Koo
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.33 no.3
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    • pp.205-212
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    • 2000
  • Experimental investigations on the removal of protein, total suspended solids and turbidity from aquacultural water were carried out by using three types of foam separator: counter current air driven type foam separator (CCADFS), high speed aeration type foam separator (HSAFS) and venturi type foam separator (VFS). The decrease of flow rate by CCADFS, HSAFS and VFS were $0.4,\;66.1,\;77.2 {\%}$ respectively. Protein removal rates by three types foam separator were decreased with the increased hydraulic residence time (HRT). Bellw 0.32 minute and 0.21 minute of hydraulic residence times, protein removal rate of HSAFS and YES was higher than that of CCADFS, respectively. Protein removal rate of VFS was lower than that of HSAFS at any HRT. As increasing the HRT, protein removal efficiency of CCADFS was increased, but that of HSAFS and VES were decreased. The changes of removal rates and efficiencies of total suspended solid and turbidity were similar to proteins.

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A study on the optimization design of pulse air jet system to improve bag-filter performance (여과집진기의 탈진 성능 향상을 위한 충격 기류 분사 시스템 최적화 설계에 관한 연구)

  • Hong, Sung-Gil;Jung, Yu-Jin;Park, Ki-Woo;Jeong, Moon-Heon;Lim, Ki-Hyuk;Suh, Hye-Min;Shon, Byung-Hyun
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.13 no.8
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    • pp.3792-3799
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    • 2012
  • The dedusting characteristics of pulse air jet type dedusting system which is widely applied in the industries were identified by utilizing the computational fluid dynamics (CFD) and the dedusting performance in modified shape of dedusting unit was compared in this study. The review on the dedusting air volume, air stream distribution and inflow velocity distribution on each shape of dedusting part showed that the case of installing the nozzle on the blow tube (Case-3) and the case of installing the double intaking tube to the venturi (Case-4 and Case-5) were more excellent than the structure (Case-1) which is widely applied in the field in its amplification effect on the air volume and extension of stream width. The specification of venturi was decided to apply the selected Case-5 for the option of the commercial back filter. It is considered that the dedusting air volume will be maintained in maximum in the case of 50 mm and 90 mm for the diameter of internal and external intaking pipe respectively.

[Retracted]Improving Performance of Foam Proportioner Utilizing Metering Venturi Type ([논문철회]미터링 벤츄리를 이용한 포소화약제 혼합장치의 성능개선)

  • Joo, Seung-Ho;Kong, Ha-Sung;Gong, Ye-Som
    • Fire Science and Engineering
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    • v.29 no.3
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    • pp.48-52
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    • 2015
  • In this study, we have evaluated whether the mixing ratio is proper by creating a mixing device for foam proportioner that mainly is employed in practice utilizing a metering venturi type. In case of the mixing ratio for 3%, water under pressure of 76 mm in diameter and the original liquid of a foam fire extinguishing agent of 31.75 mm in diameter have showed up the fluctuation rate just as much as 3.1~3.5% of the mixing ratio. Because water under pressure of 101.6 mm in diameter and the original liquid of a foam fire extinguishing agent of 38.1 mm in diameter have showed up 3.3~3.7% of the fluctuation rate, water under pressure of 101.6 mm in diameter and the original liquid of a foam fire extinguishing agent of 38.1 mm in diameter have satisfied 3.0~3.9% of performance criterion. And also, in case of the 6% of mixture rate, water under pressure of 76.2 mm in diameter and the original liquid of a foam fire extinguishing agent of 31.75 mm in diameter have showed up the fluctuation rate just as much as 6.4~6.8% of the mixing ratio. Because water under pressure of 101.6 mm in diameter and the original liquid of a foam fire extinguishing agent of 38.1 mm in diameter have showed up 6.0~6.8% of the fluctuation rate, water under pressure of 101.6 mm in diameter and the original liquid of a foam fire extinguishing agent of 38.1 mm in diameter have satisfied 6.0~7.0% of performance criterion.

A Preconditioning Method for Two-Phase Flows with Cavitation

  • Shin B.R.;Yamamoto S.
    • 한국전산유체공학회:학술대회논문집
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    • 2003.10a
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    • pp.181-182
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    • 2003
  • A preconditioned numerical method for gas-liquid to-phase flow is applied to solve cavitating flow. The present method employs a density based finite-difference method of dual time-stepping integration procedure and Roe's flux difference splitting approximation with MUSCL-TVD scheme. A homogeneous equilibrium cavitation model is used. The method permits simple treatment of the whole gas-liquid two-phase flow field including wave propagation, large density changes and incompressible flow characteristics at low Mach number. By this method, two-dimensional internal flows through a venturi tuve and decelerating cascades are computed and discussed.

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최적비율을 적용한 LPG/Air 강제 혼합기 개발

  • Park, Seong-Sik;Kim, Nam-Jin
    • 한국전산유체공학회:학술대회논문집
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    • 2010.05a
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    • pp.491-492
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    • 2010
  • 기존에 사용중인 저압용 벤튜리 타입 혼합기는 0.32kg/cm2에서 열리고 0.28kg/cm2에서 닫히도록 설정되어 있다. 이 방식은 증가하는 도시가스 공급량을 따라갈 수 없기 때문에 강제 혼합기를 개발 현장에 적용하고자 한다. 본 연구를 통해서 개발하고자하는 강제 혼합기는 제어밸브을 통하여 가스 62.5%, 압축공기 37.5%의 비율로 희석하여 서지탱크로 보내진다. 완성된 혼합기를 이용한 열량실험 결과 유량이 변하여도 일정한 열량이 나옴을 알 수 있었다.

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