• Title/Summary/Keyword: Water flow rate

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전기전도도를 이용한 CSO의 유량 추정 (The Flow rate estimation of CSOs using EC Data)

  • 최원석;송창수
    • 상하수도학회지
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    • 제25권5호
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    • pp.751-757
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    • 2011
  • The monitoring technique based on electrical conductivity (EC) can provide researchers with some advantages in maintenance management and is cost-effective as compared with existing CSOs monitoring. In this study, the flow rate estimation using EC data was executed in two sites where storm overflow chamber had installed. In the result of A-site, R2 of second order multinomial between dilution ratio of EC and observed flow rate was showed the range of 0.68 ~ 0.77. And $R^{2}$ of B-site was 0.62 ~ 0.81. On the other hand, cumulative frequency of A-site was 43.4 ~ 52.2% in the relative error level of under 20%. And B-site was 10.1 ~ 46.5%. The flow rate estimation formula was improved through consideration of some parameters including antecedent dry days and rainfall duration. And difference between estimated flow rate and observed flow rate in total rainfall event was very small.

해양환경 변화가 알루미늄합금 희생양극의 효율에 미치는 영향에 관한 연구 (A Study on the Influence of Al Alloy Sacrificial Anode Efficiency due to Marine Environmental Variation)

  • 김도형
    • 한국해양공학회지
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    • 제14권2호
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    • pp.106-111
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    • 2000
  • Recently it was reported that the life of Al Sacrifical anode is being used in port piers has been significantly shortened compared with the original design life (e.g. average life shortened from 20 years to 13-15 year) Those factors involving these problems mentioned above were seemed to be a quality of anode material and diverse environmental factors such as pH flow rate temperature Dissolved oxygen Chemical oxygen demand and resistivity etcm In this study flow rate and contamination degree(pH) of sea water affecting to sacrificial anode life hve been investigated in terms of electrochemical characteristics of Al alloy sacrificial anode It was known that the lifetime of Al alloy anode was shortened not only by increasing of self-corrosion quantity by varying flow rate of sea water but also by increasing corrosion current density due to the potential difference increment between Al anode and steel structure cathode by varying contamination degree of sea water. Especially when anode current density is from 1mA/cm2 to 3mA/cm2 and flow rate of sea water is under 2m/s anode current efficiency is 90% above However flow rate is over 2m/s anode current efficiency fell down sharply due to erosion corrosion as well as galvanic corrosion.

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Y 스트레이너형 자동 정유량 조절 밸브의 개발 (Development of Y Strainer Type Automatic Flow Rate Regulating Valve)

  • 윤준용;권우철
    • 한국유체기계학회 논문집
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    • 제10권1호
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    • pp.49-55
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    • 2007
  • An 'Y' strainer type automatic flow rate regulating valve, which functions are to remove impurities from hot water inside the pipe and to maintain a constant flow rate regardless of variations of the differential pressure between valve inlet and outlet at the same time, is developed for distributing hot water equally to several pipes with district heating or central heating system. Numerical analysis of the three dimensional turbulent flow field in a valve shape is carried out to confirm the flow field whether the designed regulator shape is acceptable or not. The final developed valve improves installation time and cost and maintenance ability comparing with set-up 'Y' strainer and regulator separately. Tolerance for the nominal flow rate is also satisfied within ${\pm}5%$.

Drifter를 이용한 저수지 수리거동 조사 (용담댐을 중심으로) (Observation of Reservoir Current Using Drifter (The Case Study of Yongdam Reservoir))

  • 이요상;고덕구;채효석;한경민
    • 생태와환경
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    • 제45권2호
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    • pp.200-209
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    • 2012
  • The current of the water body is very important information for the water quality management on reservoirs. It is applied to hydraulics and water quality model for simulation. In this regard, the current characteristic of water body is the basic information that can be used to predict various conditions. However, it is very slow flowing and is affected by the reservoir operations and external factors. As such, an accurate measurement of the current is a difficult problem. In order to measure the water current, we constructed a drifter. According to the result of flow survey at Yongdam reservoir, 5m and 10 m depth layer flow was investigated from the upstream to the downstream, during a flood period. Maximum flow rate of 5 m depth is 13.8 cm $sec^{-1}$ and 10 m depth shows 4 cm $sec^{-1}$, respectively. But 2m depth shows a backward flow and maximum flow rate is 4 cm $sec^{-1}$. Density currents flow plays the role of back flow in reservoirs. Flow velocity in the reservoir was measured in the range of 1~2 cm $sec^{-1}$, at normal flow season, and the flow direction were different for each survey. This phenomenon occurs because the reservoir volume is very large, compared to the inflow and outflow volume.

암모니아/물 흡수식 냉동기의 대향류 판형 재생기의 수치모델

  • 지제환;정은수;정시영
    • 설비공학논문집
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    • 제13권10호
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    • pp.1034-1041
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    • 2001
  • A numerical model which simulates the flow boiling process of the ammonia/water solution within a plate type generator for ammonia/water absorption refrigerators was developed. The ammonia/water solution flows downward under gravity and the ammonia/water vapor generated by flow boiling flows upward. The heating medium flows counter to the ammonia/water solution. The flow pattern within the generator was assumed to be a bubbly flow, and the liquid and vapor phases were assumed to be saturated. It was shown that the boiling of ammonia occurred mainly in the upper part of the generator. The effects of the heating medium inlet temperature, the mass flow rate of the heating medium and the mass flow rate of ammonia/water solution into the generator on the generation of ammonia/water vapor were investigated.

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온실 난방을 위한 모세관형 태양열 집열기의 성능에 미치는 유량의 효과에 관한 연구 (The Effects of Water Flow Rates on the Performance of a Capillary Tube Solar Collector for Greenhouse Heating)

  • 유영선;장유섭;홍성기;윤진하;정두호;강영덕
    • 생물환경조절학회지
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    • 제5권1호
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    • pp.57-64
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    • 1996
  • To use effectively the solar energy in greenhouse heating, a high performance solar collector should be developed. And then the size of the solar collector and thermal storage tank should be determined through the calculation of heating load. The solar collector must be set in the optimum tilt angle and direction to take daily solar radiation maximally, and the flow rate of heat transfer fluid through the solar collector should be kept in the optimum range. In this research, the performance tests of a capillary tube solar collector were performed to determine the optimum water flow rate and the results summarized as follows. 1. The regressive equations for efficiency estimations of the capillary tube solar collector in the open loop were modeled in the water flow rate of 700-l,000 $\ell$/hr. 2. The optimum water flow rate of the solar collector was estimated by the second order polynomial regression and the maximum efficiency was 80% at the water flow rate of 850 $\ell$/hr. 3. The solar thermal storage system consisted of a capillary tube solar collector and a water storage tank was tested at the water flow rate of 850 $\ell$/hr in the closed loop, and obtained the solar thermal storage efficiency of 55.2%. 4. As the capillary tube solar collector engaged in this experiment was made of non-corrosive polyolefin tubes, its weight was as light as 1/30 of the flat plate solar collector made of copper tubes. Therefore it was considered to be suitable for the greenhouse heating system.

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온수 추출과정 동안 축열조 내의 열성층 특성 및 온수 이용률에 관한 연구 (A Study on Thermal Stratification Characteristics and Useful Rate of Hot Water in Thermal Storage Tank during Hot Water Extraction Process)

  • 장영근;박정원
    • 설비공학논문집
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    • 제14권6호
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    • pp.503-511
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    • 2002
  • Heat flow characteristics during hot water extraction process was studied experimentally. Data were taken at various outlet port type for the fixed inlet port type, inlet-outlet temperature differences and mass flow rates. In this study, the temperature distribution in a storage tank and an outlet temperature were measured to predict a degree of stratification in the storage tank, and a useful rate of hot water was analysed with respect to the variables dominating a extraction process. Experimental results show that the degree of stratification and useful rate of hot water are all high in a low flow rate in case of using modified distributor I (MDI) as the outlet port type.

An Experimental Study on the Performance of Air/Water Direct Contact Air Conditioning System

  • Yoo, Seong-Yeon;Kwon, Hwa-Kil
    • Journal of Mechanical Science and Technology
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    • 제18권6호
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    • pp.1002-1009
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    • 2004
  • Direct contact air conditioning systems, in which heat and mass are transferred directly between air and water droplets, have many advantages over conventional indirect contact systems. The purpose of this research is to investigate the cooling and heating performances of direct contact air conditioning system for various inlet parameters such as air velocity, air temperature, water flow rate and water temperature. The experimental apparatus comprises a wind tunnel, water spray system, scrubber, demister, heater, refrigerator, flow and temperature controller, and data acquisition system. The inlet and outlet conditions of air and water are measured when the air contacts directly with water droplets as a counter flow in the spray section of the wind tunnel, and the heat and mass transfer rates between air and water are calculated. The droplet size of the water sprays is also measured using a Malvern Particle Analyzer. In the cooling conditions, the outlet air temperature and humidity ratio decrease as the water flow rate increases and as the water temperature, air velocity and temperature decrease. On the contrary, the outlet air temperature and humidity ratio increase in the heating conditions as the water flow rate and temperature increase and as the air velocity decreases.

VOF 다상유동 해석을 이용한 침사지 유동특성 연구 (Study on flow characteristics of the grit chamber using VOF multi-phase flow simulations)

  • 윤정환
    • 한국가시화정보학회지
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    • 제19권2호
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    • pp.63-73
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    • 2021
  • It is essential to accurately predict the change in water level, velocity, and flow rate for each passage of the grit chamber according to the operating conditions of the pump. In this study, VOF multiphase flow analysis was performed, and the flow characteristics of the grit chamber were predicted. As a result of simulations, the sedimentation phenomenon after the entrance of the grit chamber channel is expected to occur on the side walls. When 6 channels are used, the average speed of the channels is about 52% of the design standard, and when 4 channels are used, the value increases to 74% of the design standard. The average water level in the channels tends to decrease as the flow velocity increases, and the water level in the absorption well with a larger flow rate is maintained lower than that in the absorption well with a smaller flow rate.

기포를 동반한 유동장에서의 냉각원과 주위의 해수동결에 관한 실험적 연구 (An Experimental Study on Sea Water Freezing Behavior Along Horizontal Cooled Cylinder With Bubbly Flow)

  • 박대식;윤석훈;김명환;이영호;오철
    • Journal of Advanced Marine Engineering and Technology
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    • 제25권4호
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    • pp.825-832
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    • 2001
  • This study was experimentally performed to investigate freezing behavior of sea water along horizontal cooled a circular tube with bubbly flow. The experiments were carried out for a variety of parameter, such as sea water velocity, air-bubble flow rate, and cooled-tube temperature. The shape of freezing layer, freezing rate and salinity of frozen layer were observed and measured. And the flow patterns around cooled tube were visualized using the PIV to analyze the relationship between the flow structure and the freezing characteristics. It was found that the experimental parameters gave a great influence on the freezing rate and the salinity of the frozen layer.

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