• Title/Summary/Keyword: 이론전산학

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Study on Computational Fluid Dynamics(CFD) Simulation for De-NOx in the incinerator at Taebaek city (태백시 소각로 내 NOx 제거를 위한 전산유체역학(CFD) simulation 연구)

  • Kim, Ji-Hyun;Park, Young-Koo
    • Journal of the Korean Applied Science and Technology
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    • v.30 no.2
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    • pp.320-332
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    • 2013
  • The feed air to MSW incinerator influences on the residence time of combustion gas, removal of unburnt ash and exiting gas temperature. Thus the secondary air volume could present sufficient residence time which can maintain the exiting temperature over $850^{\circ}C$. The secondary air also relates directly with the turbulence in the inside of combustion chamber, which finally provide the stable combustion condition. The present study designed a modern incinerator for a field scale, and evaluation of the potential amount of primary air based on the daily combustible quantity. From the evaluated primary air volume, the secondary air flow rate could be estimated, and its dynamic behavior was verified. In addition, the obtained air volume enables to find an optimum operation condition of the combustion. As a result of the CFD simulation, the air ratio 75 : 25 between primary and secondary air amount was optimum ratio than design criteria 72 : 28. And the flow velocity ratio of front-back of secondary air jet nozzle was found excellent at 1 : 3. In addition, the result of applied to the plant, the removal efficiency of NOx and CO generation would concentration of CO.

A Study on the Development of Land Suitability Analysis System using GSIS in the Landuse Planning (토지이용계획에 있어 GSIS를 이용한 적지분석시스템 개발에 관한 연구)

  • Lim, Seong-Hyeon;Cho, Gi-Sung
    • Journal of Korean Society for Geospatial Information Science
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    • v.3 no.2 s.6
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    • pp.43-61
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    • 1995
  • The national land use plan that targets the whole national land and all kinds of urban plans that targets a city or a part of city must be performed continuously now and after that. Therefore, the importance of land use plan, that is included in those plans, is very big and crucial. This study scrutinizes the detail zoning land suitability analysis which bases on urban basis plan and the GSIS application plan about allocation, applied various basic theory which is arranged in that course to study area, and try to develop the land use suitability analysis system, a application system The programing language used in system development is the AML of ARC/INFO. On this study, the results divide into four parts. First, we develop the land use suitability analysis system and can simplify and automatize a complicated analysis course and this system will be more useful to the land use suitability analysis. Second, the analysis range is expanded, considering the circumstance environmental factor of planning area outside. So we can implement more comprehensive analysis. Third, we apply a precedency conception and a legal restrictive element that base on urban characteristics and urban space structure theory to this study, develop a computerized method about distributive method, and can allocate the detail zone in the various ways. Finally, the next studies that can clear the detail zone suitability criteria and the correlation of the relationship of materials are essential to improve the accuracy and confidence in this analysis.

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A Study on the Effect of the Orifice Shape on Oil Outflow from a Damaged Ship (사고 선박 손상부 형상이 기름 유출량에 미치는 영향 연구)

  • Park, Il-Ryong
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.28 no.4
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    • pp.620-631
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    • 2022
  • This paper shows the numerical prediction of the change in oil outflow rate according to the orifice shape of a damaged ship by using the computational fluid dynamics (CFD) analysis method. It also provides discharge coefficients for various orifice shapes to be used in theoretical prediction approaches. The oil outflow from the model ship was analyzed using a multiphase flow method under the condition that the Froude and Reynolds number similitudes were satisfied. The present numerical results were verified by comparing them with the available experimental data. Along with the aspect ratio of the orifice and the wall thickness of the cargo tank, the effects of the orifice shapes defined by mathematical figures on the oil outflow were investigated. To consider more realistic situations, the investigation of the ef ect of the crushed iron plate around the damaged part was also included. The numerical results confirmed the change in oil outflow time for various shapes of the damaged part of the oil tank, and discharge coefficients that quantify the viscous effects of those orifice shapes were extracted. To verify the predicted discharge coefficients, they were applied to an oil spill estimation equation. As a result, a good agreement between the CFD and theoretical results was obtained.

The Present State and Solutions for Archival Arrangement and Description of National Archives & Records Service of Korea (국가기록원의 기록물 정리기술의 현황과 개선방안)

  • Yoon, Ju-Bom
    • Journal of Korean Society of Archives and Records Management
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    • v.4 no.2
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    • pp.118-162
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    • 2004
  • Archival description in archives has an important role in document control and reference service. Archives has made an effort to do archival description. But we have some differences and problems about a theory and practical processes comparing with advanced countries. The serious difference in a theory is that a function classification, maintenance of an original order, arrangement of multi-level description are not reflected in practical process. they are arranged in shelves after they are arranged by registration order in a unit of a volume like an arrangement of book. In addition, there are problems in history of agency change or control of index. So these can cause inconvenience for users. For improving, in this study we introduced the meaning and importance of arrangement of description, the situation and problem of arrangement of description in The National Archives, and a description guideline in other foreign countries. The next is an example for ISAD(G). This paper has chapter 8, the chapter 1 is introduction, the chapter 2 is the meaning and importance of arrangement of description, excluding the chapter 8 is conclusion we can say like this from the chapter 3 to the chapter 7. In the chapter 3, we explain GOVT we are using now and description element category in situation and problem of arrangement of description in Archives. In the chapter 4, this is about guideline from Archives in U.S.A, England and Australia. 1. Lifecycle Date Requirement Guide from NARA is introduced and of the description field, the way of the description about just one title element is introduced. 2. This is about the guideline of the description from Public Record Office. That name is National Archives Cataloguing Guidelines Introduction. We are saying "PROCAT" from this guideline and the seven procedure of description. 3. This is about Commomon Record Series from National Archives of Australia. we studied Registration & description procedures for CRS system. In the chapter 5, This is about the example which applied ISAD to. Archives introduce description of documents produced from Appeals Commission in the Ministry of Government Administration. In the chapter 6, 7. These are about the problems we pointed after using ISAD, naming for the document at procedure section in every institution, the lack of description fields category, the sort or classification of the kind or form, the reference or identified number, the absence description rule about the details, function classification, multi-level description, input format, arrangement of book shelf, authority control. The plan for improving are that problems. The best way for arrangement and description in Archives is to examine the standard, guideline, manual from archives in the advanced countries. So we suggested we need many research and study about this in the academic field.

A Fluid Analysis Study on Centrifugal Pump Performance Improvement by Impeller Modification (원심펌프 회전차 Modification시 성능개선에 관한 유동해석 연구)

  • Lee, A-Yeong;Jang, Hyun-Jun;Lee, Jin-Woo;Cho, Won-Jeong
    • Journal of the Korean Institute of Gas
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    • v.24 no.2
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    • pp.1-8
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    • 2020
  • Centrifugal pump is a facility that transfers energy to fluid through centrifugal force, which is usually generated by rotating the impeller at high speed, and is a major process facility used in many LNG production bases such as vaporization seawater pump, industrial water and fire extinguishing pump using seawater. to be. Currently, pumps in LNG plant sites are subject to operating conditions that vary depending on the amount of supply desired by the customer for a long period of time. Pumps in particular occupy a large part of the consumption strategy at the plant site, and if the optimum operation condition is not available, it can incur enormous energy loss in long term plant operation. In order to solve this problem, it is necessary to identify the performance deterioration factor through the flow analysis and the result analysis according to the fluctuations of the pump's operating conditions and to determine the optimal operation efficiency. In order to evaluate operation efficiency through experimental techniques, considerable time and cost are incurred, such as on-site operating conditions and manufacturing of experimental equipment. If the performance of the pump is not suitable for the site, and the performance of the pump needs to be reduced, a method of changing the rotation speed or using a special liquid containing high viscosity or solids is used. Especially, in order to prevent disruptions in the operation of LNG production bases, a technology is required to satisfy the required performance conditions by processing the existing impeller of the pump within a short time. Therefore, in this study, the rotation difference of the pump was applied to the ANSYS CFX program by applying the modified 3D modeling shape. In addition, the results obtained from the flow analysis and the curve fitting toolbox of the MATLAB program were analyzed numerically to verify the outer diameter correction theory.