• Journal of ILASS-Korea
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• v.9 no.2
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• pp.24-33
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• 2004

The effect of the working fluid flow conditions and nozzle geometry on the spray performance of a twin-fluid nozzle used in Selective Catalytic Reduction is investigated experimentally. The liquid pressure is varied in the range of 0.3atm to 1.5atm and the air pressure is varied from the 0.5atm to 3.0atm. relative position between liquid nozzle(internal nozzle) and air nozzle(external nozzle) tip changes front 1mm inside the air nozzle to 1mm outside the air nozzle. The orifice diameter of the air nozzle is varied with 5mm. 6mm and 7mm. Spray visualization is realized with CCD-Camera. SMD(Sauter Mean Diameter) and mean particle velocities are measured by PDPA(Phase Doppler Particle Analyzer) under various experimental conditions. The measuring point is 300mm away from the nozzle tip in the downstream spray. The experimental results are that spray angle is depended air flow rate because nozzle diameter, air pressure and nozzle tip relative positions are related air flow rate. SMD is depended air flow rate and water flow rate. Also, SMD is increased when water flow rate is bigger. SMD is decreased when Air flow rate is bigger.

• Journal of environmental and Sanitary engineering
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• v.17 no.4
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• pp.1-9
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• 2002

In order to define about concern with discharge and water-quality, it is calculated drought flow, low flow, normal flow and wet flow in Chungju watershed from flow duration analysis. Water quality modeling study is performed for forecasting at upstream of Chungju lake. It is devided method of modeling into before and after the equipment of environmental treatment institution. And it is estimated the change of water quality. Before the equipment of environmental treatment, BOD concentration is increased from 23000 to 2006 years at all site and decrease on 2012 years. The rate of increasing BOD concentration is showed height between 2000 years and 2003 years most of all site. And after the equipment of environmental treatment, it is showed first grade of BOD water quality in most of sample site beside Jucheon river. The result of water quality modeling using drought flow showed that a lot of pollution occurred. And water quality using wet flow is good, so much discharge make more improve water quality than little discharge.

• Structural Monitoring and Maintenance
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• v.3 no.4
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• pp.335-347
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• 2016

One of major errors in flow rate measurement for two-phase flow using an Electrical Capacitance Sensor (ECS) concerns sensor sensitivity under temperature raise. The thermal effect on electrical capacitance sensor (ECS) system for air-water two-phase flow monitoring include sensor sensitivity, capacitance measurements, capacitance change and node potential distribution is reported in this paper. The rules of 12-electrode sensor parameters such as capacitance, capacitance change, and change rate of capacitance and sensitivity map the basis of Air-water two-phase flow permittivity distribution and temperature raise are discussed by ANSYS and MATLAB, which are combined to simulate sensor characteristic. The cross-sectional void fraction as a function of temperature is determined from the scripting capabilities in ANSYS simulation. The results show that the temperature raise had a detrimental effect on the electrodes sensitivity and sensitive domain of electrodes. The FE results are in excellent agreement with an experimental result available in the literature, thus validating the accuracy and reliability of the proposed flow rate measurement system.

• 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.

• Journal of the Korean Society of Propulsion Engineers
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• v.2 no.2
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• pp.83-87
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• 1998

To reduce the supersonic jet noise from the liquid rocket engine, water injetion silencers were designed and tested. Test variables were the mass flow rate of water jet, the length of primary pipe and the diameter of expansion pipe. Followings are the results of this study. 1. From the same mass flow rate of water, longer primary pipe was more effective to reduce the noise. 2. Noise level was significantly reduced with increasingly water flow rate. 3. The optimum water flow rate was 10～12 times of the propellant flow rate. 4. By installing expansion pipe, noise level was reduced approximately 30㏈ compared to without expansion pipe

• Journal of Korean Society on Water Environment
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• v.28 no.3
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• pp.394-400
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• 2012

We drew the stage-discharge relations of Byeokgye Stream, located in Yangpyeong-gun, Gyeonggi-do, and analysed the correlation between items of water pollutants by measuring the flow rate and water pollutants thirty-four times from April 2010 to December 2010. The results showed that it tended to be low water season from April to June and from October and December, while tending to be water season from July to September. The average flow rate was $2.137\;m^3/sec:\;0.464\;m^3/sec$ in low water season and $13.970\;m^3/sec$ in high water season. The stage-discharge curve thereon was $Q=40.107{\times}(h-1.200)^{2.877}$. As to the correlations, the correlation between the water temperature and COD was 0.58, and the correlations of SS with BOD and COD were 0.46 and 0.40 respectively. The correlation between SS and T-P was 0.73, showing higher than other items.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.37 no.11
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• pp.1031-1036
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• 2013

The motor-driven water pump boiler for a water circulating mattress generates noise and vibration as it supplies a large water flow rate. A non-pump boiler can reduce such noise and vibration, however, the water circulation flow rate becomes lesser than that in motor-driven water pump boilers, and a large temperature deviation occurs between the inlet and the outlet of the mattress. In this research, a new non-pump boiler for water circulating mattress is developed and its performance is experimentally validated and compared with the existing non-pump boilers. The experimental results show that temperature response time is improved and temperature deviation is reduced.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.2079-2084
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• 2007

A small-scale thermoelectric cooling system was built in an effort to enhance the performance of the refrigeration system by utilizing the water-cooled jacket which was attached on the hot side of the thermoelectric module. Considered design parameters for the water-cooled jacket included the geometry of the flow passage inside the jacket and the flow rate of cooling water. The higher flow rate of cooling water in the jacket resulted in a better performance of the refrigeration system. The introduction of geometrical complexity of the cooling water flow passage to the cooling jacket also showed significant improvement on the performance of the thermoelectric refrigeration system such as the cooling capacity and the COP of the refrigeration system.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.1
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• pp.139-143
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• 2019

Measurement of flow rate is required in various fields. Water meters are often used at home, and flow meters are used in water and sewage plants, petrochemical industries and so on.. A system is needed to monitor the flow rate in real time and notify immediately when flow rate is abnormal. Recently, with the development of the IoT it is possible to construct such devices at low cost. WeMos can be programmed with Arduino IDE as a mini wifii IoT module. The flow sensor can output a digital pulse proportional to the flow rate. In this paper, we developed the flow monitoring and warning system using WeMos and IoT technology. When the system operates, it calculates the flow rate, sends the value as JSON format to the server, monitors the flow rate as graph from the remote with the smartphone. We also implement the system to promptly send alert message to the smart phone using Pushbullet when the flow rate is abnormal.

• Journal of Ecology and Environment
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• v.30 no.2
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• pp.109-119
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• 2007

The effect of water flow on the growth of Gafrarium tumidum was studied in the field using open cages constructed with stainless steel net and perspex in which holes were drilled. Cages with different flows (25, 50 and 75% of the control) were made by varying the area of perspex being drilled. Reduction in flow rate was directly proportional to the undrilled area, and the mean flow rate of the different treatment groups varied from 3.12 cm/s for the 25% exposure to 12.48 cm/s for the control cages. At the end of the 3-month experiment, no significant differences in sediment characteristics were found among the treatments. Growth in shell length, shell weight and tissue dry weight was, however, positively correlated with flow rate. Percentage increases ranged from $3.0{\sim}8.3%$ for shell length, $9.9{\sim}23.1%$ for shell weight and $17.2{\sim}53.3%$ for tissue dry weight. Condition index of the clam was not significantly different among the treatments. Seston depletion effect could reduce growth in G. tumidum only when water flow was reduced to 25% of the control. G. tumidum also exhibited different responses in shell and tissue growth at low flow rates, in which shell growth continued to decrease as flow rate decreased whereas tissue growth was relatively independent of low flows at 25 and 50% of the control. It was suggested that when seston flux was reduced at slow flows, it would be a better strategy for G. tumidum to channel energy for gonad development instead of shell growth during the reproductive stage.