• Journal of Ocean Engineering and Technology
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• v.29 no.5
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• pp.331-341
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• 2015

A degasser is a separation unit used in drilling to separate gas from the drilling mud. The degasser used in offshore drilling was developed at an early stage of drilling. Since its development, the design of the degasser’s internal structure has been optimized, with many limitations due to the restrictions of experimental and computational performance measurement methods. Despite the recent development of CFD technology for multiphase flow analysis, CFD has only been used in a limited way for degasser internal flow analysis and design optimization. In this study, a design optimization procedure for a degasser’s internal structure design was proposed, and CFD analyses of three types of internal structural designs were performed to evaluate the separation performance. The CFD result for each design type was used for the design optimization and, as the result, an optimized design is proposed.

• Journal of the Korean Society of Industry Convergence
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• v.25 no.6_2
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• pp.1063-1069
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• 2022

In modern industry, vacuum has grown into an indispensable industrial field. The performance of the vacuum pump in the degasser system among mud treatment system facilities was verified by a numerical analysis method. The degasser system is an equipment for removing the gas contained in the mud, and it is a work process that requires a vacuum. This study analyzed the vacuum pump performance of the degasser used in drilling for resource development of onshore and offshore plants. The vacuum pump used in the degasser system was designed with a discharge rate of 0.099kg/s. The DM(Design Modeler) program of ansys workbench 17.2 was used to modify the model of the vacuum pump used in the degasser system. And for performance analysis, CFX, which is known to be suitable for rotating system analysis, was used. Finally the performance analysis results of the vacuum pump and the prototype performance test results were compared and analyzed.

• Journal of the Korean Society of Industry Convergence
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• v.24 no.6_2
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• pp.763-772
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• 2021

Drilling Mud Treatment Systems are widely used for Oil Gas drilling mud circulation, horizontal directional drilling mud recycling, geothermal drilling, mining, coal exploration drilling, water well drilling. Degasser is a device used in drilling to remove gasses from drilling fluid which could otherwise form bubbles. For small amounts of entrained gas in a drilling fluid, the degasser can play a major role of removing small bubbles that a liquid film has enveloped and entrapped. As with the desander, its purpose is to remove unwanted solids from the mud system. The smaller cones allow the desilter to efficiently remove smaller diameter drill solids. In this study, a simulation study is conducted on the degasser of the facility in the Mud Treatment System to conduct a performance review on the gas separation in the mud.

• Journal of Korea Foundry Society
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• v.20 no.6
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• pp.407-418
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• 2000

The effect of various factors on the results of degassing of AC4C aluminum alloy melt by using rotary degasser were investigated. The difference between the effects of nitrogen gases of commercial pure and high purity grades on the degassing results was not significant. The optimum degassing condition was obtained. The effect of holding and degassing temperature was not significant, either. The result of degassing was deteriorated by the modification treatment of eutectic silicon, meanwhile improved by the grain refining. The effect of the latter was stronger than that of the former when the melt was treated simultaneously. The volume fractions of hydrogen porosity of the castings obtained from the molds with water moisture such as natural and green sand molds were much higher than those from the molds without that such as pep-set and $CO_2$ molds.

• Nuclear Engineering and Technology
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• v.46 no.1
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• pp.39-46
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• 2014

A total loss of all heat sinks is considered a severe accident with a low probability of occurrence. Following a total loss of all heat sinks, the degasser/condenser relief valves (DCRV) become the sole means available for the depressurization of the primary heat transport system. If a nuclear power plant has a total loss of heat sinks accident, high-temperature steam and differential pressure between the primary heat transport system (PHTS) and the steam generator (SG) secondary side can cause a SG tube creep rupture. To protect the PHTS during a total loss of all heat sinks accident, a sufficient depressurization capability of the degasser/condenser relief valve and the SG tube integrity is very important. Therefore, an accurate estimation of the discharge through these valves is necessary to assess the impact of the PHTS overprotection and the SG tube integrity of the primary circuit. This paper describes the analysis of DCRV discharge capacity and the SG tube integrity under a total loss of all heat sink using the CATHENA code. It was found that the DCRV's discharge capacity is enough to protect the overpressure in the PHTS, and the SG tube integrity is maintained in a total loss of all heat accident.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 1993.11a
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• pp.103-108
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• 1993

In nuclear power plants using pressurized water as the main coolant, it is necessary to maintain system pressure within operational range. During transients, the coolant shrinks and expands causing insurge and outsurge of coolant in the pressurizer. In CANDU system, the pressure is controlled mainly by the pressurizer/degasser-condenser system. In CANDU system, the control of heat transport system pressure is achieved by giving heat to the pressurizer by activating the heaters to compensate a diminution in pressure or by removing heat from the pressurizer by bleeding steam to the degasser-condenser to compensate an increase in pressure. This study aims at developing a theoretical model capable to simulate various operational transients in the CANDU primary heat transport system (PHTS), applicable to CANDU engineering simulator on real time basis.

• Journal of Korea Foundry Society
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• v.10 no.4
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• pp.316-323
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• 1990

To improve free-cutting property, fine Pb, Bi particles is necessary to be distributed evenly in Al-Cu alloy. The control of added element size and distribution are very difficult because of the insolubility and gravity segregation of Pb, Bi in the matrix. Therefore, in this study, mechanical stirring of the melt, inert gasbubbling, the addition of degasser are used for the fine distribution of Pb, Bi particles. The best distribution are obtained by stirring with 500 rpm for 10min., Ar gas bubbling with 600cc/min for 5min. and degassing with 0.8wt% degasser. As increasing cooling rate, fine grain size and finely dispersed particles were observed. The optimum pouring temperature was $650^{\circ}C$.

• Proceedings of the Korean Nuclear Society Conference
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• 1996.05b
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• pp.643-648
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• 1996

Recent failures of Heat Transport (HT) system Liquid Relief Valves (LRVs) at several CANDU 6 plants resulted in heavy water spills. A multi-discipline KAERI task team along with AECL representatives was set up to assess the specific implications on the Wolsong 2/3/4 station. The study applied the knowledge gained from the generic study by conducting a fundamental review of the specific design of Welsong 2/3/4. The purpose of the study was to demonstrate compliance with the relevant codes and licensing regulations and to identify the improvements to the design and operating procedures applicable to Wolsong 2/3/4. This paper presents the key recommendations of this study.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.8
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• pp.4713-4716
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• 2014

Several methods that have been used to manage a degasing process in recent years, such as an injection method that uses aluminum molten metal powder and chemicals, and the input method that supplies argon and nitrogen, or chlorine gas using a gas blow-tube. On the other hand, these methods have some problems, and it is a difficult process to handle pollution due to the production of considerable toxic gases, such as chlorine and fluoride gas, irregular effects, and lowering work efficiency due to the excessive processing time. The problems that are most fatal are the production of considerable sludge due to a reaction of aluminum molten metal with chemicals, loss of metals, and the decreasing life of refractory materials. To solve these problems, this study developed a technology that is related to continuous casting of molten aluminum metal and monolithic degasing apparatus.

• Journal of Korea Foundry Society
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• v.43 no.6
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• pp.271-278
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• 2023

In the present study, A356 melt degassing experiments were conducted under various impeller rotation speed and inert gas flow rate conditions to determine changes in the melt temperature, composition and density during a degassing treatment. The melt temperature was found to decrease gradually as the degassing time increased, but a clear correlation between the impeller rotation speed or inert gas flow rate and the melt heat loss could not be confirmed. Regardless of the impeller rotation speed or inert gas flow rate, the Mg and Ti contents in the A356 melt scarcely changed, even after degassing for more than 10 minutes, while Sr contents decreased at the maximum degassing rate of 70 ppm. From a quantitative analysis of the degassing rate under each experimental condition based on the hydrogen concentration in the melt derived from the melt density and the degassing model equation, the inert gas flow rate was found to affect the degassing rate rather than the impeller rotation speed under the degassing operation condition employed in the present study.