• Title/Summary/Keyword: Small tank scale

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A Study on the Characteristics of Two-Step-Flow-Control Fluidic Device (2단 유량제어 Fluidic Device의 특성에 관한 연구)

  • Cho, Bong-Hyun;Bae, Yoon-Yeong;Park, Jong-Kyun;Yoo, Seong-Yeon
    • The KSFM Journal of Fluid Machinery
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    • v.4 no.3 s.12
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    • pp.53-61
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    • 2001
  • Vortex type Fluidic Device(FD) which is installed at the bottom of Safety Injection Tank(SIT) controls the discharge flow rate from the tank. In case of loss of coolant accident the injection water flows into primary system in two steps; initial high flow rate for certain period of time and subsequent low flow rate. By two-step control of the discharge flow rate, FD can ensure the effective use of water in the tank. A small-scale FD has been tested to obtain a required flow characteristics maintaining full pressure and height of prototype, which are the major contributing parameters. Through the testing of many different arrangements of internal geometry of FD, most appropriate one was selected and its performance data was obtained. As characteristics of FD, time dependent Euler number, flow rate and pressure are presented and discussed. Also a method to predict the full size FD is presented.

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Development of Amalgamated Septic Tank using Mineral Sintered Body (광물 소결체를 이용한 합병정화조 개발에 관한 연구)

  • 김광수;김영훈;강헌찬
    • Resources Recycling
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    • v.9 no.4
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    • pp.56-62
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    • 2000
  • This study was introduced an amalgamated septic tank system using mineral sintered body was made from non-metallic minerals with a ability being attached or accelerating a vitality of soil microorganism for the effective wastewater treatment. Experimentally, we made an amalgamated septic tank appling anaerobic-aerobic process experimental facilities to two personal houses for handling a residental sewage directly on a small scale from the place of origin. The results are shown as follows; The COD\ulcorner and BOD of effluent were about 10 mg/l after the treatments and T-N removal efficiency was 60-70%. Moreover these results suggested the possibility of denitrification without adding organics and more than 80% of T-P removal also showed the possibility of wastewater treatment biologically.

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Investigations of Mixing Time Scales in a Baffled Circular Tank with a Surface Aerator

  • Kumar, Bimlesh;Patel, Ajey;Rao, Achanta
    • Environmental Engineering Research
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    • v.16 no.1
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    • pp.47-51
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    • 2011
  • The oxygen transfer rate is a parameter that characterizes the gas-liquid mass transfer in surface aerators. Gas-liquid transfer mechanisms in surface aeration tanks depend on two different extreme lengths of time; namely, macromixing and micromixing. Small scale mixing close to the molecular level is referred to as micromixing; whereas, macromixing refers to mixing on a large scale. Using experimental data and numerical simulations, macro- and micro-scale parameters describing the two extreme time scales were investigated. A scale up equation to simulate the oxygen transfer rate with micromixing times was developed in geometrically similar baffled surface aerators.

Pullout resistance of concrete anchor block embedded in cohesionless soil

  • Khan, Abdul J.;Mostofa, Golam;Jadid, Rowshon
    • Geomechanics and Engineering
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    • v.12 no.4
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    • pp.675-688
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    • 2017
  • The anchor block is a specially designed concrete member intended to withstand pullout or thrust forces from backfill material of an internally stabilized anchored earth retaining wall by passive resistance of soil in front of the block. This study presents small-scale laboratory experimental works to investigate the pullout capacity of a concrete anchor block embedded in air dry sand and located at different distances from yielding boundary wall. The experimental setup consists of a large tank made of fiberglass sheets and steel framing system. A series of tests was carried out in the tank to investigate the load-displacement behavior of anchor block. Experimental results are then compared with the theoretical approaches suggested by different researchers and codes. The appropriate placement of an anchor block and the passive resistance coefficient, which is multiplied by the passive resistance in front of the anchor block to obtain the pullout capacity of the anchor, were also studied.

Measures and Proposal for Korean Solar Water Heating System (한국형 태양열 온수급탕 시스템의 대책과 제안)

  • Kim, Sung-Soo;Hong, Hi-Ki
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.20 no.9
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    • pp.631-636
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    • 2008
  • Solar thermal systems are recently refocused by higher oil prices, but did not completely restore the people's confidence owing to the past bad systems. Several types of solar water heating systems were analyzed in characteristics and some proper systems were proposed under Korean climates and system scale. As a small system, natural circulation system should be installed only in a southern region of Korea, with a freeze protection valve instead of heating coil for freeze protection. In most area of Korea, the forced circulation type with a heat exchange coil inside a thermal storage tank or with a spiral-jacketed storage tank, proposed and verified by the authors, has a merit of stable performance and freeze protection.

A Study on the Determination of Water Storage-Supply Capacity of Agricultural Reservoir (소규모 농업용 저수지의 저류량-용수공급능력 결정에 관한 연구)

  • 안승섭;정순돌;이증석;윤경덕;장인수
    • Journal of Environmental Science International
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    • v.11 no.12
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    • pp.1217-1226
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    • 2002
  • This study aims at the effective estimation of water supply capacity of small scale reservoir and the proposal of the data which is necessary to establish the water resources management plan of down stream area of the reservoir in the future by comparison and examination about reservoir operation technique for the security of agricultural water in small scale reservoir. The result of flow calculation by Tank model is used for the input data as the inflow data which is needed for the analysis of water supply capacity. Stochastic method, simulation method, and optimization method are used to examine the water supply capacity, and water security amount is compared with each method. From the analyses of water supply capacities by each method, slightly different results are shown in spite of the effort to compare them equally using input data such as inflow data under equal conditions, and the comparison of water supply capacities by each method are as follows; linear planning method, simulation method, and transition probability matrix method in the order of amount from the largest. It is thought that the simulation method in which comparatively reasonable application of the inflow data is possible and is simulated in successive time series dam operation of the three methods used in this study thus, simulation model is proper to estimate the water supply capacity of agricultural small scale reservoir. And it is judged that the heightening of efficiency of water resources utilization according to the development of downstream area of dam may be possible using the upward readjusted water supply amount of $55.18{\tiems}10^6ton$ and $63.7{\times}10^6ton$ at 95% and 90% supply reliability respectively which are above the planning water supply amount of $50.0{\times}10^6$ton when the simulation method is introduced as the standard.

A Fundamental Study on the Power Prediction Method of Ship by using the Experiment of Small Model (소형 모형선을 이용한 실선마력추정에 대한 연구)

  • Ha, Yoon-Jin;Lee, Young-Gill
    • Journal of the Society of Naval Architects of Korea
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    • v.51 no.3
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    • pp.231-238
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    • 2014
  • In this study, the self-propulsion tests are performed in INHA towing tank. And the effective wake characteristics of the KVLCC2 and the KCS models are compared by the experimental results. The form factor is independent of Reynolds number. To estimate the hydrodynamic performance of a full scale ship, the form factor is determined to consider attendant on Reynolds number. In this research, the power predictions are carried out considering the form factor difference of model and full scale ship. The results of this research could be used as one of the fundamental data to the powering performance prediction.

A Study on the Small Wastewater Collection System for Rural Area (농촌지역 소규모 오수차집시스템에 관한 연구)

  • Yoon, Chun-Gyeong;Yoo, Chan
    • Journal of Korean Society of Rural Planning
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    • v.4 no.2
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    • pp.20-28
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    • 1998
  • A small wastewater collection system for rural area was reviewed and the small diameter gravity (SDG) was thought to be the most appropriate. The pilot-scale field experiment was performed for 15 months and the result is presented. The wastewater used for experiment was the effluent of septic tank in Kon-Kuk University, and components are similar to normal domestic wastewater. The SDG experimental system included 2" PVC pipe and reverse-sloped lower section is included. No clogging problem by solids was experienced at the points where flow direction changed. The pipe-breaking by freezing was experienced during the cold weather, thus proper protection may be required where severe weather is expected.

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Factors Affecting Process Temperature and Biogas Production in Small-scale Rural Biogas Digesters in Winter in Northern Vietnam

  • Pham, C.H.;Vu, C.C.;Sommer, S.G.;Bruun, S.
    • Asian-Australasian Journal of Animal Sciences
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    • v.27 no.7
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    • pp.1050-1056
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    • 2014
  • This study investigated the main factors influencing digester temperature and methods to reduce heat losses during the cold season in the subtropics. Four composite digesters (two insulated and two uninsulated) were buried underground to measure their internal temperature ($^{\circ}C$) at a depth of 140 cm and 180 cm, biogas production and methane ($CH_4$) concentration in biogas from August to February. In parallel the temperature of the air (100 cm above ground), in the slurry mixing tank and in the soil (10, 100, 140, and 180 cm depth) was measured by thermocouple. The influent amount was measured daily and the influent chemical composition was measured monthly during the whole experimental period. Seasonal variations in air temperature significantly affected the temperature in the soil, mixing tank and digester. Consequently, biogas production, which is temperature dependent, was influenced by the season. The main factors determining the internal temperature in the digesters were insulation with Styrofoam, air temperature and temperature of slurry in the mixing tank. Biogas production is low due to the cold climate conditions in winter in Northern Vietnam, but the study proved that storing slurry in the mixing tank until its temperature peak at around 14:00 h will increase the temperature in the digester and thus increase potential biogas production. Algorithms are provided linking digester temperature to the temperature of slurry in the mixing tank.

Development of Process for Village Scale Wastewater Treatment Using Biofilter and Sulfur-limestone (바이오필터와 황-석회석을 이용한 마을하수 처리 공정 개발)

  • Kim, Tae-Kyu
    • Journal of The Korean Society of Agricultural Engineers
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    • v.49 no.2
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    • pp.75-86
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    • 2007
  • This process which has a connection of biofilter and sulfur-limestone has been developed to treat organic substances including BOD, COD and SS etc. and to treat sulfur-limestone is for denitrification.. The whole process consists of chemical reaction tank, sedimentation tank, trickling filter, denitrification tank The trickling filter is equipped with a reactor filled with absorptive filter, and the sulfur denitrification tank is filled with sulfur-limestone mixed media. After setting up practical facilities whose capacity is 60 tons a day, we have observed the removal efficiencies of pollutants through 60 experiments during Summer and Winter seasons. The average concentration of polluted water was BOD for 3.6 mg/L, $COD_{Mn}$ for 11.3 mg/L, SS for 2.8 mg/L, T-N for 8.6 mg/L, and T-P for 0.8 mg/L, and the rate of treatment efficiencies 96.5%, 84.7%, 96.5%, 79.2%, and 80.8%, respectively was found through the experiments. The average treatment efficiency for BOD and $COD_{Mn}$ was 85.0% and 55.7%, respectively and the average removal efficiency for NH4+-N was 84.9% in the trickling filter. The removal efficiency in the denitrification tank is as follows; The removal rate of $NO_3^--N$ was as high as 93.2% within the compass of pH 6.3 to 7.3 through $16.8{\sim}37.0mg/L$ flown into $NO_3^--N$ and $0.1{\sim}8.3mg/L$ outflown. It had observed that this process has implemented highly efficient and advanced treatment without external carbon sources and internal recycle during its process. In conclusion, this process is suitable for a sewerage in a small village due to the merits of low power consumption and easy maintenance.