• Proceedings of the Korean Nuclear Society Conference
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• 1996.11a
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• pp.395-400
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• 1996

Scoping analyses for the Safety Injection System (SIS) configuration for Korean Next Generation Reactor (KNGR) are peformed in this study. The KNGR SIS consists of four mechanically separated hydraulic trains. Each hydraulic train consisting of a High Pressure Safety Injection (HPSI) pump and a Safety Injection Tank (SIT) is connected to the Direct Vessel Injection (DVI) nozzle located above the elevation of cold leg and thus injects water into the upper portion of reactor vessel annulus. Also, the KNGR is going to adopt the advanced design feature of passive fluidic device which will be installed in the discharge line of SIT to allow more effective use of borated water during the transient of large break LOCA. To determine the feasible configuration and capacity of SIT and HPSI pump with the elimination of the Low Pressure Safety Injection (LPSI) pump for KNGR, licensing design basis evaluations are performed for the limiting large break LOCA. The study shows that the DVI injection with the fluidic device SIT enhances the SIS performance by allowing more effective use of borated water for an extended period of time during the large break LOCA.

• Transactions of the Korean Society of Mechanical Engineers
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• v.6 no.3
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• pp.256-260
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• 1982

This paper presents the characteristics of fuel spray in a diesel engine. In this paper, in order to obtain spray droplet size in a diesel engine, water was injected into the cylinder at room temperature and pressure by injection system. Spray droplet size was measured by liquid immersion technique with a lubricant used as an immersion liquid for spray water from injection nozzle. In this experiment, single hole type throttle nozzle are used at same operating conditions, which included opening pressure of nozzle, fuel delivery, and injection speed. Sauter mean diameter decrease with the increase of injection pressure and decrease in injection nozzle diameter. The rate of spray penetration increased with increasing injection pressure and diameter of injection nozzle at the constant spray conditions.

• Journal of ILASS-Korea
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• v.25 no.3
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• pp.95-102
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• 2020

Six shear coaxial injectors for a 3 tonf-class liquid rocket engine using oxygen and methane as propellants were designed and manufactured by considering geometric design parameters such as a recess length and a taper angle. Cold-flow tests on the injectors were performed using water and air as simulants. By changing the water mass flow rate and air mass flow rate, the injection pressure drop under single-injection and bi-injection was measured. The discharge coefficients through the injector oxidizer-side and fuel-side were calculated and the discharge coefficient ratio between bi-injection and single-injection was obtained. Under single-injection, the recess served to reduce the injection pressure drop on the injector fuel-side. For the injectors without recess, the discharge coefficients under bi-injection were almost the same as those under single-injection. However, for the injectors with recess, the taper angle and bi-injection had a significant effect on the discharge coefficient.

• Journal of Korean Society on Water Environment
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• v.37 no.3
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• pp.168-174
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• 2021

Mixing is a very important unit in water treatment process. A mechanical stirring method is generally used for mixing, but recently, the use of pressurized water mixing method (pump diffusion flash mixer) has gained interest because it is more advantageous in terms of mixing time, noise, energy consumption, and maintenance. The following conclusions were obtained from the study of pressurized water mixing method by Computational Fluid Dynamics. Firstly, the mixing degree in the pipe increased as the density of water increased. Secondly, even if the relative velocity between flow rate in the pipe and the pressurized water was constant, the mixing degree decreased as the flow velocity in the pipe increased. Thirdly, the stronger the injection energy the higher the mixing degree. It was also found that the mixing degree was greatly affected by the injection velocity as compared to the injection flow amount. Finally, the required energy to achieve 95% mixing degree at the distance of 10 times diameter in big pipes of 500 mm to 3000 mm was 0.3 to 4.5 kJ. The result of this study could be used in the process design of injection with water purification chemicals, such as, ozone, chlorine, and coagulant.

• Economic and Environmental Geology
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• v.45 no.3
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• pp.307-315
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• 2012

In this paper, a laboratory model test was conducted to evaluate grouting efficiency of ordinary portland cement(OPC) and micro cement used in MIS(Micro-Injection Process System). For this research, a injection equipment was developed for pressure permeation which can evenly simulate various grouting tests in a laboratory and suggested a standard for the production of the test specimen. Using the injection device, the laboratory injection tests of grouts were prepared with water/cement ratio of 1:1, 2:1, 3:1, 4:1, and 5:1. The analysis of injection test for pressure permeation showed that the efficiency of injection increases linearly as the water/cement ratio increases. Comparison of efficiency of the injection indicates that MIS with a relatively smaller average diameter shows more efficient injection than the OPC. In the low ratio of water/cement as 2:1~1:1, the injection efficiency of OPC was especially poor. Also, a nonlinear grout volume-injection time is represented by a hyperbolic model and grout volume predicted by hyperbolic model was compared with the value measured. From the comparison, it shows that the hyperbolic model has the potential of evaluating the efficiency of grouting.

• Journal of Physiology & Pathology in Korean Medicine
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• v.34 no.6
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• pp.334-340
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• 2020

Nypa fruticans Wurmb. (NF) has been used as a folk remedy to treat inflammatory diseases in Asia. In this study, we aimed to investigate the protective effect of NF water extract on cerulein-induced acute pancreatitis (AP). To measure the protective effects of NF on AP, AP was induced via intraperitoneal injection of cerulein (50 ㎍/kg) hourly for 6 h in mice. NF water extract (100, 250, or 500 mg/kg) or saline was administrated to intraperitoneal injection 1 h before the first injection of cerulein. The mice were sacrificed at 6 h after the final injection of the cerulein. Pancreas, and blood sample were taken for further analysis. Administration of NF water extract inhibited the pancreatic injury, the elevation of pancreatic weight/ body weight ratio, and the elevation of serum digestive enzymes such as amylase and lipase during cerulein-induced AP in mice. Also, pancreas MPO activity, which represents neutrophil infiltration, was inhibited by administration of NF water extract. Taken together, administration of NF water extract reduces the severity of cerulein-induced AP, which suggests a clinical basis that NF could be a potential agent to prevent AP.

• Journal of Korean Society on Water Environment
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• v.27 no.1
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• pp.104-109
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• 2011

The removal efficiencies of 2-methylisoborneol (MIB) and geosmin were investigated to reveal removal characteristics of typical organic compounds causing disagreeable taste and odor at the conventional water treatment plant installed with pulsator clarifier patented by the French company $Degr{\acute{e}}mont$. The injection rate of Powdered Activated Carbon (PAC) into water was changed step wisely as we conducted jar tests in the laboratory and water treatment in the actual plant. 2-MIB concentration decreased linearly while geosmin did exponentially along with the injection rate of PAC at our jar tests. The removal efficiency of geosmin by PAC injection was considerably higher than that of 2-MIB. In the real pulsator clarifier, 2-MIB concentration started decreasing as the injection rate reached up to 10 mg/L of PAC. On the other hand, the concentration of geosmin in water decreased proportional to the injection rate of PAC. In the sand filtration, removal efficiencies of 2-MIB and geosmin on July were much higher than those on March. It was carefully suggested beforehand and found afterwards that general microorganisms notably existed in the sand filter with no chlorine in filter influent and backwash water and the sand filter biologically activated removed much more odor compounds. It was considered as the reason why the removal efficiency of 2-MIB and geosmin was increased. The microbial activity maybe increased in summer with water temperature rising and low filtration rate possibly increased contact time between odor compounds and general microorganisms.

• Nuclear Engineering and Technology
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• v.56 no.3
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• pp.1052-1065
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• 2024

Advanced Pressurized Water Reactors (APWRs) and Boiling Water Reactors (BWRs) employ a suppression pool as a heat sink to prevent containment overpressure. Steam can be discharged into the pool through multi-hole spargers or blowdown pipes in both normal and accident conditions. Direct Contact Condensation (DCC) creates sources of momentum and heat. The competition between these two sources determines the development of thermal stratification or mixing of the pool. Thermal stratification is of safety concern as it reduces the cooling capability compared to a completely mixed pool condition. In this work we develop a scaling approach to prediction of the thermal stratification in a water pool induced by steam injection through spargers. Experimental data obtained from large-scale pool tests conducted in the PPOOLEX and PANDA facilities, as well as simulation results obtained using validated codes are used to develop the scaling. Two injection orientations, namely radial injection through multi-hole Sparger Head (SH) and vertical injection through Load Reduction Ring (LRR), are considered. We show that the erosion rate of the cold layer can be estimated using the Richardson number. In this work, scaling laws are proposed to estimate both the (i) transient erosion velocity and (ii) the stable position of the thermocline. These scaling laws are then implemented into a 1D model to simulate the thermal behavior of the pool during steam injection through the sparger.

• Journal of Environmental Science International
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• v.22 no.4
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• pp.453-461
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• 2013

This study, changes in raw water quality is to indicate on the efficiency of ozone treatment of each pollutant as compared to derive the appropriate operating measures. The appropriate selection for injection rate of pre-ozone and did not inject pre-ozone assess changes in the water. When good water quality, you not injected of pre-ozone to evaluate the economic efficiency of electricity and put the most cost-effective ozone concentration were evaluated. Evaluation remove organic matter and chlorophyll-a concentration level in experiments with each factor of the water DOC> 2.5 mg/L, THMFP> 70 ${\mu}g/L$, Chl-a> 30 $mg/m^3$or less constant process, if you do not need to put pre-ozone showed little impact. It also does not put you in pre-ozone appropriate produce enough power rate savings was calculated as approximately 90 million won. Ability to remove organic materials and the ability to produce disinfection byproducts, and cost-effective decisions by considering the concentration of injection if pre-ozone 1 mg/L was investigated by the appropriate concentration of ozone injection.

• Journal of Korean Society of Water and Wastewater
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• v.33 no.4
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• pp.311-319
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• 2019

The purpose of this study was to analyze water treatment characteristics, including the efficiency of removing algae from water purification plants, by installing a demonstration facility for decontamination of algae, including natural algae remover injection equipment, in the water purification plant. Jar-test showed that the optimum injection of natural decontaminant was 20 mg/L. Of the water contaminant treatment efficiency of the intake and water purification plants, Chl-a averaged 74.0% elimination efficiency from $5.0mg/m^3$ to $1.3mg/m^3$ and the maximum treatment efficiency was 91.5% removal efficiency when the inflow concentration of Chl-a was $11.8mg/m^3$. In addition, 51.2% and 47.1% of the taste and odor indicator items, geosmin and 2-MIB, resulted from the overgrowth and decaying of algae, respectively, to identify toxic substances and odor reduction effects. In addition, elimination efficiencies of SS and Turbidity materials were higher than 70.0%. In the injection of natural algae remover, no effects such as sudden changes in water quality due to secondary reactions were found, and appropriate levels were maintained under water treatment conditions.