• 제목/요약/키워드: water flow measurement

검색결과 681건 처리시간 0.032초

Enhancing Effect of Organic Substances on Hydroxyl Radical Generation During Ozonation of Water: Stopped-Flow ESR Technique

  • Han, Sang-Kuk
    • Bulletin of the Korean Chemical Society
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    • 제25권12호
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    • pp.1907-1910
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    • 2004
  • Generation of hydroxyl radical, one of their major active species in ozonation of water was directly observed with spin-trapping/electron spin resonance (ESR) technique using 5,5-dimethyl-pyrrolidine-1-oxyl (DMPO) as a spin-trapping reagent. Hydroxyl radical was trapped with DMPO as a stable radical, DMPO-OH. 80 mM of ozone produced $1.08{\times}10^{-6}$M of DMPO-OH, indicating that 1.4% of ${\cdot}$OH is trapped with DMPO if ${\cdot}$OH is produced stoichiometrically from ozone. Humic acid suppressed DMPO-OH generation in a dose-dependent manner. Generation rate of DMPO-OH was determined with ESR/stopped-flow measurement. Phenol derivatives increased the amount and generation rate of DMPO-OH, indicating that phenol derivatives enhance·OH generation during ozonation of water.

동진지구 김제간선 내 주요 용수지선의 흐름 특성 (Flow Characteristics of Lateral Irrigation Canals Diverted from Kimje Main Canal in Dongjin Irrigation Area)

  • 최진규;손재권;김진택;김영주
    • 한국농공학회논문집
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    • 제54권5호
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    • pp.113-121
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    • 2012
  • The study was carried out to investigate the dimension of irrigation canal, and measure the water flow of those diverted from Kimje main canal in Dongjin irrigation area. The rating curves indicating the relationships between water level and discharge of the lateral canals were induced using the measured data with high regression coefficients of 0.957~0.999 at inlet points and 0.932~0.998 at end points, respectively. And Manning's roughness coefficients were estimated as the ranged from 0.015 to 0.074 at inlet points and 0.056 to 0.089 at end points with rectangular type of concrete open irrigation canals, the Manning's roughness coefficients of the end points were less than those values of the end points, which may be considered as the deposition of the bottom sediments.

지역난방 아파트에 대한 난방에너지 실측 및 시뮬레이션 (Measurement and Simulation of Heating Energy for Apartments with District Heating)

  • 이은주;이두영;홍희기;김영균
    • 설비공학논문집
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    • 제26권12호
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    • pp.572-578
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    • 2014
  • Heating energy was measured in an apartment housing unit with a district heating system, varying the kind of hot water distributors. Ondol coils passing through a living room raised the temperature of the room where the heating was turned off. Including this characteristic of Ondol heating into the modeling, we performed simulations and showed a verification by comparison with the results of measurements. As a result, a main flow control method, which changes hot water flow rate supplied to a housing unit according to the thermal load, can reduce the supplied flow rate and lower the return temperature, compared with a constant flow method. That can result in decreased heat loss in utility-pipe conduits even though the heating energy supplied is almost the same. An outdoor reset control that raises the temperature of the supplied hot water if the outdoor temperature falls has the effect of a quicker response in heating than the reduced flow rate and return temperature.

안쪽축이 회전하는 환형관내 헬리컬 유동장의 실험적 연구 (Experimental Study on the Helical Flow Field in a Concentric Annulus with Rotating Inner Cylinders)

  • 황영규;김영주
    • 대한기계학회논문집B
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    • 제24권6호
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    • pp.822-833
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    • 2000
  • This experimental study concerns the characteristics of a transitional flow in a concentric annulus with a diameter ratio of 0.52, whose outer cylinder is stationary and inner one rotating. The pressure drops and skin-friction coefficients have been measured for the fully developed flow of water and that of glycerine-water solution (44%) at a inner cylinder rotational speed of $0{\sim}600$ rpm, respectively. The transitional flow has been examined by the measurement of pressure drops and the visualization of flow field, to reveal the relation of the Reynolds and Rossby numbers with the skin-friction coefficients and to understand the flow instability mechanism. The present results show that the skin-friction coefficients have the significant relation with the Rossby numbers, only for laminar regime. The occurrence of transition has been checked by the gradient changes of pressure drops and skin-friction coefficients with respect to the Reynolds numbers. The increasing rate of skin-friction coefficient due to the rotation is uniform for laminar flow regime, whereas it is suddenly reduced for transitional flow regime and, then, it is gradually declined for turbulent flow regime. Consequently, the critical (axial-flow) Reynolds number decreases as the rotational speed increases. Thus, the rotation of inner cylinder promotes the early occurrence of transition due to the excitation of taylor vortices.

투수층흐름에서의 마찰계수 (Friction Factor of Seepage Flow)

  • 유동훈;권순국
    • 한국해안해양공학회지
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    • 제6권4호
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    • pp.397-403
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    • 1994
  • 레이놀즈수에 대한 투수층흐름 마찰계수의 관계식을 개발하고자 투수층수조 실험을 실시하였다. 사용된 투수층수조는 물이 거의 수평으로 흐르도록 유도하는 장치이다. 각 구간마다 수두의 변화로 한번의 실험으로 다양한 수리조건을 재현할 수 있는 포괄성을 갖고 있으며, 여러 조의 수리실험을 실시하였다. 보다 광범위한 수리조건을 재현하기 위하여 여러 크기의 골재를 사용하였고 유출량도 다양하게 송출하였다. 기존자료를 이용하여 형상계수 산정식을 개발하였으며, 금번 수조실험의 결과를 이용하여 레이놀즈수가 1부터 600까지의 조건에서 투수층흐름 마찰계수를 구하는 양해법 산정식을 개발하였다. 관측된 마찰계수의 분포경향을 고려하였을 때, 레이놀즈수가 600보다 큰 난류조건에서도 동일 산정식을 사용할 수 있으리라 기대된다.

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경사각을 갖는 적층판식 유수분리기의 유수분리 효율에 관한 연구 (A Study on the Oil/Water Separation Efficiency of Laminated Plate Type Oily water Separator with Inclined Angle)

  • 한원희;김준효;최민선
    • Journal of Advanced Marine Engineering and Technology
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    • 제25권2호
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    • pp.365-374
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    • 2001
  • Its a tendency to strengthen related international was as the importance on marine oil pollution recently becomes the issue. According to the regulation of IMO, oil discharge from ships is allowed under 15PPM only and oil filtering equipment is essential. Oily water separator of laminated plate type which is one of gravity type separator can be use as assistant equipment for the oil filtering system to meet the present IMO standard, because it fits well to process large amount of rich oil with high specific gravity. The purpose of this paper is to investigate an efficiency of oil/water separation with the characteristics of laminated plate arrangement. The analyse of oil contents for oil-water mixture were carried out in order to find an efficiency of oil/water separation and an experimental study was simultaneously carried out to investigate internal flow characteristics of separator by visualization method and PIV(Particle Image Velocimetry) measurement at three spaces of plates for 5, 10 and 15 mm with variation of inlet flow rates of $0.25m^3$/h and $0.5m^3$/h. The experimental results showed that the space of the plates acts a significant role in the separating process.

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고온층계통의 이온교환기에 의한 연구로 수조 상부 방사선의 저감효과에 대한 연구 (Study for Reduction Effect of Pool Top Radiation in Research Reactor by Using Ion Exchanger of Hot Water Layer)

  • 박용철;박종호
    • 한국유체기계학회 논문집
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    • 제2권4호
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    • pp.40-47
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    • 1999
  • A hot water layer (HWL hereinafter) was installed at the depth of 1.2 m from the pool surface to reduce the radiation level at the pool top. After the HWL system was improved by the replacement of the filter with the Ion Exchanger to capture the Na-24, to purify the pool water of HWL and finally to reduce the radiation at the pool top. It was confirmed by the performance test of the pump and the measurement of the pressure difference through the Ion Exchanger and the strainer, that the flow characteristics of HWL system was not adversely affected after the system modification. Also the flow analysis using the pressure loss coefficients of the Ion Exchanger and strainer, calculated by the Darcy formula, could predict the flow variations by pressure changes within $10\%$ error in comparison with the field test results. It was also confirmed that HWL was maintained with the depth of 1.2 m from the pool surface because each electric water heater was electrically and thermodynamically maintained at 30 kW and the temperature of HWL was maintained with $5^{\circ}C$ higher temperature than that of pool water. Finally, it was confirmed that the pool top radiation was saturated and stabilized below 10000 nG/hr within 24 hours as the ion exchanger captured the main nucleus, Na-24 and purified the pool water of HWL.

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원전 배관의 반복 측정 데이터에 대한 신뢰도 분석 방법 (Reliability Analysis Method for Repeated UT Measurement Data in Nuclear Power Plants)

  • 윤훈;황경모
    • Corrosion Science and Technology
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    • 제12권3호
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    • pp.142-148
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    • 2013
  • Safety is a major concern in Nuclear Power Plants (NPPs). Piping systems in NPPs are very complex and composed of many components such as tees, elbows, expanders and straight pipes. The high pressure and high temperature water flows inside piping components. As high speed water flows inside piping, the pipe wall thinning occurs in various reasons such as FAC (Flow Accelerated Corrosion), LDIE (Liquid Droplet Impingement Erosion) and Flashing. To inspect the wall thinning phenomenon and protect the piping from damages, piping components are checked by UT measurement in every overhaul. During every overhaul, approximately 200~300 components (40,000~60,000 UT data) are examined in NPPs. There are some methods from EPRI for evaluating wear rate of components. However, only few studies have been conducted to find out the raw data reliability for the wear rate evaluation. Securing the reliable raw data is the key factor for a reasonable evaluation. This paper suggests the reliability analysis method for the repeatedly measured data for wear rate evaluation.

PDA를 이용한 유량측정시스템 개선방안 연구 (Improvement study of river discharge measurement system using PDA)

  • 황의호;양재린;이근상;고덕구
    • 한국수자원학회:학술대회논문집
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    • 한국수자원학회 2006년도 학술발표회 논문집
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    • pp.942-947
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    • 2006
  • 수자원공사에서는 유량측정 이래 크게 개선되지 않고 있는 유량자료의 신뢰도를 획기적이면서 가시적으로 향상시킬 수 있는 방법을 고안하여 '04년 'PDA를 이용한 유량측정시스템'을 개발하여 시스템을 운영하고 있다. 그러나 기존 시스템은 모든 연산이 모바일 인터넷 기반으로 운영됨으로써 DB 전송 상 통신장애가 빈번하게 발생하여 측정자에게 많은 불편함이 초래하고 있으며, 유량측정 지점에 대한 유동적인 대처 방안 등이 미비한 실정이다. 이에 따라, 본 연구에서는 기존 시스템의 운영상 발생되는 통신장애 문제점을 극복하고, 유량측정 결과의 신뢰도를 향상시키기 위하여 개선방안을 마련하고 현장에 적용할 수 있는 시스템을 개발하고자 하였다. 이를 위해, 기존 시스템 상세 분석을 통한 시스템 구성상의 문제점 및 적용 알고리즘 상의 문제점을 도출하여 개선 시스템에 반영할 수 있는 방안을 제시하였으며, 자료 전송시 통신장애 극복방안을 제시할 수 있는 시스템 개발 방법을 도입하였다. 또한, 유량변화율 및 불확실도의 개선과 최신 IT기술 도입을 통한 기존 유속측정 장비의 개선 방안을 제시하였다. 이를 통해 보다 개선된 유량측정방법을 제공함으로써 유량측정업무 체계를 개선시켜주고, 신뢰성 높은 유량측정 결과 취득이 가능할 것으로 사료된다.

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디지털 영상처리기술을 이용한 비접촉식 유체-구조 연동운동3차원 측정시스템 개발에 관한 연구 (A Study on Developments of Three-dimensional Measurement System for Flow-Structure Interactions using Digital Image Processing)

  • 도덕희;상지웅;황태규;조용범;편용범
    • 한국해양공학회:학술대회논문집
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    • 한국해양공학회 2004년도 학술대회지
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    • pp.274-278
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    • 2004
  • A simultaneous measurement system that can analyze the flaw-structure interactions has been developed This system consists of four CCD cameras, two for capturing instantaneous flaw fields and two for tracking a solid body. The three-dimensional vector fields around a cylinder are measured while the motion of the cylinder forced by the flow field is measured simultaneously with the constructed system The cylinder is pended in the working fluid of a water channel and the surface of the working fluid is forced sinusoidal to make the cylinder bounced Reynolds number for the mean main stream is about l000. The interaction between the flaw fields and the cylinder motion is examined quantitatively.

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