• 제목/요약/키워드: Natural Circulation

검색결과 483건 처리시간 0.027초

자연 윤리학 구성의 제 요소 - 한의사 윤리를 중심으로 - (Elements of Natural Ethics - Focusing on Korean Medicine Ethics -)

  • 안영수;김민주;오정명;민유리;류정아
    • 대한한의학원전학회지
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    • 제33권2호
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    • pp.13-32
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    • 2020
  • Objectives : To define an everyday ethics for students and doctors of Korean Medicine, people who desire treatment, cultivation and healing through Korean Medical means by determining its conditions and characteristics. Ways of constructing its contents fit for contemporary society were discussed. Methods The threefold Heaven-Earth-Human theory, Yinyang theory, circulation of the Five Phases along with contents of classics such as 『Huangdineijing(黃帝內經)』, 『Guanzi(管子)』, 『Zhongyong(中庸)』, 『Daxue(大學)』, 『Beijiqianjinyaofang(備急千金要方)』, 『Donguibogam(東醫寶鑑)』 were newly interpreted or quoted for explanation. Results : The elements that construct natural ethics and Natural Ethics were established as following: the natural perspective of Nature and People, natural sustainability as fundamental principle, co-existence and initiative circulation as fundamental rules, education and cultivation of lay people, and professional character and competence. Conclusions : The authors suggest a reconstruction of the inherent philosophy, ethics, principle, rule, life guidelines of Korean Medicine within the framework of "natural ethics" and "Natural Ethics" as a prior task for better integration of traditional KM into contemporary society.

Experimental validation of simulating natural circulation of liquid metal using water

  • Lee, Min Ho;Jerng, Dong Wook;Bang, In Cheol
    • Nuclear Engineering and Technology
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    • 제52권9호
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    • pp.1963-1973
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    • 2020
  • Liquid metal-cooled reactors use various passive safety systems driven by natural circulation. Investigating these safety systems experimentally is more advantageous by using a simulant. Although numerous experimental approaches have been applied to natural circulation-driven passive safety systems using simulants, there has been no clear validation of the similarity law. To validate the similarity law experimentally, SINCRO-V experiment was conducted using Wood's metal and water for simulant of the Wood's metal. A pair of SINCRO-V facilities with length-scale ratio of 14.1:1 for identical Bo' was investigated, which was the main similarity parameter in temperature field simulation. In the experimental range of 0.2-1.0% of decay heat, the temperature distribution characteristics of the small water facility were very similar to that of the large Wood's metal facility. The temperature of the Wood's metal predicted by the water experiment showed good agreement with the actual Wood's metal temperature. Despite some error factors like discordance of Gr' and property change along the temperature, the water experiment predicted the Wood's metal temperature with an error of 27%. The validity of the similarity law was confirmed by the SINCRO-V experiments.

단순화된 피동 원자로건물 냉각계통 내 자연순환에 관한 수치적 연구 (Numerical Investigation on Natural Circulation in a Simplified Passive Containment Cooling System)

  • 서정수
    • 한국안전학회지
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    • 제33권3호
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    • pp.92-98
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    • 2018
  • The flow of cooling water in a passive containment cooling system (PCCS), used to remove heat released in design basis accidents from a concrete containment of light water nuclear power plant, was conducted in order to investigate the thermo-fluid equilibrium among many parallel tubes of PCCS. Numerical simulations of the subcooled boiling flow within a coolant loop of a PCCS, which will be installed in innovative pressurized-water reactor (PWR), were conducted using the commercially available computational fluid dynamics (CFD) software ANSYS-CFX. Shear stress transport (SST) and the RPI model were used for turbulence closure and subcooled flow boiling, respectively. As the first step, the simplified geometry of PCCS with 36 tubes was modeled in order to reduce computational resource. Even and uneven thermal loading conditions were applied at the outer walls of parallel tubes for the simulation of the coolant flow in the PCCS at the initial phase of accident. It was observed that the natural circulation maintained in single-phase for all even and uneven thermal loading cases. For uneven thermal loading cases, coolant velocity in each tube were increased according to the applied heat flux. However, the flows were mixed well in the header and natural circulation of the whole cooling loop was not affected by uneven thermal loading significantly.

Modifications and Assessment of RELAP5/MOD3.2 for HANARO Thermal-Hydraulic Safety Analyses

  • Gee Yang Han;Kwi Seok Ha
    • Nuclear Engineering and Technology
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    • 제34권5호
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    • pp.455-467
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    • 2002
  • RELAP5/MOD3.2 was modified to perform the thermal-hydraulic safety analysis for HANARO transients. Several aspects of RELAP5/MOD3.2 were modified or replaced by new features to properly simulate the unique HANARO characteristics such as the finned fuel element, the cooling mechanisms by both plate type heat exchanger and the natural circulation. Especially, the heat transfer packages were modified to be more appropriate for the safety analysis and the heat transfer models were developed for the plate type heat exchanger as well as natural circulation through the pool water. This modified version of RELAP5/MOD3.2 is renamed as RELAP5/HANARO. The thermal-hydraulic simulations of the single fuel pin test and plate type heat exchanger were peformed to assess the realistic predicting capabilities of RELAP5/HANARO and compared with experimental results and manufacturer's data in this paper. In addition, the natural circulation experiment using the scaled bundle was simulated to validate the capability of RELAP5/HANARO. The simulation results show almost similar trend with experimental data. Therefore, it is proved that RELAP5/HANARO has a confidence to use for the safety analyses of HANARO.

자원순환형 녹색마을 경관디자인 적용에 관한 연구 -김제시 중촌마을을 대상으로- (A Study on the Application of Natural Circulation -based Green Village Landscape Design-: The Case of Joongchon Village in Gimje-si)

  • 김상범;손호기;이창훈;이상영
    • 농촌지도와개발
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    • 제18권4호
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    • pp.961-981
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    • 2011
  • This study selected Joongchon Village in Gimje-si as a target, in order to apply green village design regarding regional circumstances and features within the local government, in making green village as an efficient scheme in aspect of locality for 'Low Carbon, Green Growth'. Subsequently, we conducted survey and analysis. Natural circulation-based green village of Joongchon Village in Gimje-si is a low carbon green village, based upon eco-friendly cattle shed. Even though it is the fact that the initial costs of an eco-friendly cattle shed are rather high, it is the long-term low carbon green technology that can transform livestock night soils into resources, provide them to agricultural farms, independently supply energies from by-product, and produce energies additionally. Therefore, Joongchon Village in Gimje-si is the good example of green village, applying the design which actively utilizes discharged by-product from cattle shed, so natural circulation and energy production are able as an eco-friendly green technology.

Unsteady Single-Phase Natural Circulation Flow Mixing Prediction Using CATHARE Three-Dimensional Capabilities

  • Salah, Anis Bousbia;Vlassenbroeck, Jacques
    • Nuclear Engineering and Technology
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    • 제49권3호
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    • pp.466-475
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    • 2017
  • Coolant mixing under natural circulation flow regime constitutes a key parameter that may play a role in the course of an accidental transient in a nuclear pressurized water reactor. This issue has motivated some experimental investigations carried out within the OECD/NEA PKL projects. The aim was to assess the coolant mixing phenomenon in the reactor pressure vessel downcomer and the core lower plenum under several asymmetric steady and unsteady flow conditions, and to provide experimental data for code validations. Former studies addressed the mixing phenomenon using, on the one hand, one-dimensional computational approaches with cross flows that are not fully validated under transient conditions and, on the other hand, expensive computational fluid dynamic tools that are not always justified for large-scale macroscopic phenomena. In the current framework, an unsteady coolant mixing experiment carried out in the Rossendorf coolant mixing test facility is simulated using the three-dimensional porous media capabilities of the thermal-hydraulic system CATHARE code. The current study allows highlighting the current capabilities of these codes and their suitability for reproducing the main phenomena occurring during asymmetric transient natural circulation mixing conditions.

발열체와 격막이 있고 일부가 열린 복합공간내의 자연대류-복사열전달에 관한 수치적 연구 (A numerical study on the combined natural convection and radiation in a partially open complex enclosure with a heater and partitions)

  • 김태국;민동호;한규익;손봉세;서석호
    • 대한기계학회논문집B
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    • 제21권2호
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    • pp.235-251
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    • 1997
  • A numerical simulation on the combined natural convection and radiation is carried out in a partially open rectangular enclosure with a heater by using the finite volume and the S-8 discrete ordinate methods. The fluid inside the enclosure is considered as an absorbing, emitting and anisotropic scattering media. The heater causes a natural circulation of the fluid (10$^{5}$ $^{9}$ ) which results in significant in-flow of the ambient cold fluid through the partially open wall. Comparing the results of pure convection with those of the combined convection- radiation, the combined heat transfer results with small Planck numbers (P$_{l}$ <1.0) show much stronger circulation than those of the pure convection, and the fluid circulation is more evident for larger Rayleigh numbers. When one of three radiative properties - the medium absorption coefficient, the wall reflectivity, and the scattering albedo - increases, the fluid circulation and the heat transfer in the enclosure are reduced. The location of the heater and the open ratio of the right wall are also shown to affect the fluid circulation and heat transfer significantly. However, the anisotropy of the scattering phase function is shown to be unimportant for the fluid circulation and heat transfer within the enclosure considered in this study.

동판교 신도시의 물순환 체계 구축방안 (A Study on the Establishment of Water Circulation System for the Eastern Pangyo New Town)

  • 최희선;김귀곤
    • 한국환경복원기술학회지
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    • 제12권3호
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    • pp.49-58
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    • 2009
  • This study was done to provide a case model with a concept of environmental integration based on the water circulation system. Area of interest (AOI) is the Eastern Pangyo New Town area, which has several advantages in adaptation of a water circulation system. The AOI has a potential of maintaining water resources, and has a good condition to construct the water circulation system. Research done for the purpose of the establishment of the water circulation system in the Eastern Pangyo New Town shows the following. The main sources of water supply in the water circulation system in the Eastern Pangyo New Town is from two subway stations and runoff water, along with the natural water flowing from the mountains, rain water, and stream water. It was determined that more than 35,000 tons of water would be needed for the creation of water circulation system at the Eastern Pangyo. If the creation of infrastructure for the use of runoff and rain water as well as the periodic management can be provided, it can serve as the new model for a new city with water circulation system. In addition, since the Eastern Pangyo New Town water circulation system can secure enough amount of water resources, natural drainage system (NDS) in which it can be in dry condition in non-rainy days, is applied and connected to the typical waterways. Such water circulation system has many positive aspects including the wise use of water resources, and providing wild Life animals corridors and habitats. Also, the water circulation system can lead to the environmental education to the residents and visitors on environmental awareness of the water circulation system and their environment.

전시시나리오구조 유형별 관람행동특성에 관한 연구 - 자연과학계박물관을 중심으로 - (A Study on the Characteristics of Viewing Behaviors by the Composition Type Exhibition Scenarios - Focused on Natural Science Museums -)

  • 임채진;홍수미;김민아
    • 한국실내디자인학회논문집
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    • 제15권4호
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    • pp.106-114
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    • 2006
  • The purposes of natural science museums are to educate the general public on the principles and application of science, and help them understand various aspects of science technology. Data should be analyzed by considering these educational aspects of exhibition, and the methods of presenting exhibits should be decided. Accordingly, the composition of exhibition contents with various exhibition elements has an important role at natural science museums. The relation and structure of exhibition themes are significant factors in helping visitors understand the principles of science and a system of viewing circulation can be used as an important tool for understanding the flow of exhibition. In other words, at the planning stage for the composition of exhibition contents, the relation of exhibition themes as well as the circulation patterns of viewers can induce active viewing behaviors. Therefore, centering on the patterns of viewing circulation as well as on the connectivity of exhibition themes at natural science museums, the purposes of this research are: 1) to conceptualize the composition of exhibition contents; and 2) to find elements that can induce active viewing behaviors by analyzing visitors' viewing behaviors. This research was establishing an analytical indicator of contact for viewing behaviors observed from the composition of exhibition scenarios, the active viewing patterns of engagement, first contact, and repeated contact were analyzed. First, a composition pattern with a high participation rate, in contact with exhibits, was found to induce an overall-viewing circulation and have a big ring of the composition of exhibition themes. Second, by inducing a partial-viewing circulation pattern, a high rate of first contacts was observed from a ring pattern of theme connection. Even for the structure with theme connection with depth, a high frequency of contacts with various exhibits was found when exhibition themes have a ring pattern. Third, the repeated contacts were mostly found in the form of scenarios, which has a successive structure of ring and cross patterns.