• Title, Summary, Keyword: 고온가스덕트

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Suggestion of Structural Sizing Methodology on a Coaxial Double-tube Type Hot Gas Duct for the VHTR (초고온가스로의 동심축 이중관형 고온가스덕트에 대한 구조정산 방법론 제안)

  • Song, Kee-Nam;Kim, Y.W.
    • Proceedings of the KSME Conference
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    • pp.717-724
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    • 2008
  • Very High Temperature Gas Cooled Reactor (VHTR) has been selected as a high energy heat source for nuclear hydrogen generation, which can produce hydrogen from water or natural gas. A primary hot gas duct (HGD) as a coaxial double-tube type cross vessel is a key component connecting the reactor pressure vessel and the intermediate heat exchanger for the VHTR. In this study, structural sizing methodology for the primary HGD with a coaxial double-tube of the VHTR that produces heat at temperatures in the order of $950^{\circ}C$ was suggested and a structural pre-sizing of it was carried out as an example.

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Preliminary Structural Sizing of the Co-axial Double-tube Type Primary Hot Gas Duct for the Nuclear Hydrogen Reactor (수소생산용 원자로에서 동심축 이중관형 1차 고온가스덕트의 예비 구조정산)

  • Song, Kee-nam;Kim, Y-W
    • Transactions of the Korean Society of Pressure Vessels and Piping
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    • v.4 no.2
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    • pp.1-6
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    • 2008
  • Very High Temperature Gas Cooled Reactor (VHTR) has been selected as a high energy heat source for nuclear hydrogen generation. The VHTR can produce hydrogen from heat and water by using a thermo-chemical process or from heat, water, and natural gas by steam reformer technology. A co-axial double-tube primary hot gas duct (HGD) is a key component connecting the reactor pressure vessel and the intermediate heat exchanger (IHX) for the VHTR. In this study, a preliminary design analysis for the primary HGD of the nuclear hydrogen system was carried out. These preliminary design activities include a determination of the size, a strength evaluation and an appropriate material selection. The determination of the size was undertaken based on various engineering concepts, such as a constant flow velocity model, a constant flow rate model, a constant hydraulic head model, and finally a heat balanced model.

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Thermal and Creep Analysis of an Exhaust Duct of Smart UAV with FGM (경사기능재료를 사용한 스마트 무인기 덕트의 열해석과 크리프 해석)

  • Im, Jong-Bin;Park, Jeong-Seon;Yun, Dong-Yeong;Lee, Jeong-Jin
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.34 no.1
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    • pp.65-73
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    • 2006
  • The high temperature occurs due to the combustion gas from engine in unmanned aerial vehicles (UAV). The high temperature may cause serious damages in UAV structure. The Functionally Graded Material (FGM) is chosen as a candidate material of the engine duct structure. A functionally graded material (FGM) is a two- component mixture composed by compositional gradient materials from one material to the other. In contrast, traditional composite materials are homogeneous mixtures, and involve compositions between the desirable properties of the component materials. Since significant proportions of an FGM contain the pure form of each material, the need for compromise is eliminated. The properties of both components can be fully utilized. Thermal stress analysis of FGM layers (20, 40, 60, 80 and 100) is performed in this paper. In addition, the creep behavior of FGM applied in duct structure of an engine is analyzed for better understanding of FGM characteristics.

The Effect of Temperature and Flow Rate in Hot Exhaust Gas on the NOx Emission and Flame Structure of Diffusion Flame (고온 배기가스의 온도 및 유량이 확산화염의 구조 및 NOx 발생에 미치는 영향)

  • Sohn, H.S.;Jang, S.W.;Kim, H.Y.
    • 한국연소학회:학술대회논문집
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    • pp.139-146
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    • 2001
  • The experimental study was carried out for the diffusion flame characteristics of second stage combustor with the variations of temperature and supplying rate of hot exhaust gas from first stage combustor. It also examined the flame structure and NOx formation of the second stage combustor in which the fuel(natural gas) is supplying into the mixture of oxygen hot exhaust gas from first stage combustor. The results show that the increasement of temperature and flow rate of exhaust gas lead to increase the NOx up to 30ppm with 19% $O_2$ condition

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1-D Analysis for Water Spray Cooling of Exhaust Gas in Combustor Test Facility (물 분무를 이용한 연소가스 냉각 1차원 해석)

  • Im, Ju Hyun;Kim, Myung Ho;Kim, Yeong Ryeon
    • Journal of the Korean Society of Propulsion Engineers
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    • v.19 no.1
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    • pp.61-67
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    • 2015
  • The cooling of hot exhaust gas is an important issue for the construction of combustor test facility. Water spray is an effective method for exhaust gas cooling due to its large latent heat in process of evaporation. In this study, 1-D analysis has been performed based on continuity, energy conservation, and saturated vapor property to understand water spray cooling of combustion gas. In the exhaust duct of combustor test facility, the injected water decreases combustion gas temperature, and evaporates in the combustion gas. However, some of the injected water is collected in the sump due to condensation. The evaporation of water helps combustion gas cooling, but causes pressure increase inside the exhaust duct due to increase of vapor pressure. These phenomena has been analyzed by 1-D modeling in this study. From 1-D analysis, the adequate mass flow rate of water spray to cool combustion gas and to avoid excessive pressure rise inside the exhaust duct has been decided.

Pre-conceptual Design of the Main Components for the NHDD Program (수소생산용 원자로에서 주요기기의 예비개념설계)

  • Song, Kee-Nam;Lee, S.B.;Kim, Y.W.
    • Proceedings of the KSME Conference
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    • pp.296-299
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    • 2007
  • KAERI is in the process of carrying out the Nuclear Hydrogen Development and Demonstration (NHDD) Program. The indirect cycle gas cooled reactors that produce heat at temperatures in the order of $950^{\circ}C$ are being considered in the NHDD program. For the indirect gas cooled reactors, the intermediate hear exchanger (IHX) and hot gas duct (HGD) are the main components. For the NHDD program we are in the process of establishing a conceptual design of the IHX and HGD. The pre-conceptual design activities in this study dealt with a preliminary design of the IHX and the HGD including strength and thermal expansion evaluation of the main components.

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Investigation of FIV Characteristics on a Coaxial Double-tube Structure (동심축 이중관 구조에서 유동기인진동 특성 고찰)

  • Song, Kee-Nam;Kim, Yong-Wan;Park, Sang-Chul
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.33 no.10
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    • pp.1108-1118
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    • 2009
  • A Very High Temperature Gas Cooled Reactor (VHTR) has been selected as a high energy heat source of the order of $950^{\circ}C$ for nuclear hydrogen generation, which can produce hydrogen from water or natural gas. A primary hot gas duct (HGD) as a coaxial double-tube type cross vessel is a key component connecting a reactor pressure vessel and an intermediate heat exchanger in the VHTR. In this study, a structural sizing methodology for the primary HGD of the VHTR is suggested in order to modulate a flow-induced vibration (FIV). And as an example, a structural sizing of the horizontal HGD with a coaxial double-tube structure was carried out using the suggested method. These activities include a decision of the geometric dimensions, a selection of the material, and an evaluation of the strength of the coaxial double-tube type cross vessel components. Also in order to compare the FIV characteristics of the proposed design cases, a fluid-structure interaction (FSI) analysis was carried out using the ADINA code.

The Effect of Oxygen Concentration in Hot Exhaust Gas on the $NO_{x}$ Emission of Diffusion Flame in Exhaust Gas (고온 배기가스의 산소농도가 배기가스이용 확산화염의 $NO_{x}$ 발생에 미치는 영향)

  • Sohn, H.S.;Jang, S.W.;Choi, D.S.;Kim, H.Y.
    • Proceedings of the KSME Conference
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    • pp.115-120
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    • 2001
  • The present study examined the possibility of $NO_{x}$ reduction in the high temperature industrial furnaces. duct burner of gas turbine cogeneration and two-stage gas turbine combustor. The experimental study was carried out for the diffusion flame of second stage combustor with the variations of oxygen concentration and supplying rate of hot exhaust gas from first stage combustor. It also examined the flammability range and $NO_{x}$ formation of the second stage combustor in which the fuel is supplying into the mixture of oxygen hot exhaust gas from first stage combustor. The results show that the enrichment of oxygen and increase of exhaust gas lead to increase the $NO_{x}$ up to 50 ppm with 23% $O_{2}$ condition.

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Review of the Research and Development of Ceramic Matrix Composite Materials and Future Works (세라믹 매트릭스 복합재료 연구 개발 동향 및 전망)

  • Lee, Tae Ho
    • Composites Research
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    • v.27 no.4
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    • pp.123-129
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    • 2014
  • Ceramic matrix composites (CMCs) consist of such reinforcements as carbides, nitrides, borides and oxides, which have high melting points, low density, high modulus and high strength, for the purpose of increasing toughness. These materials are used for heat shielding systems for aerospace vehicles, high-temperature gas turbine combustion chambers, turbine blades, stator vane parts, etc. Oxide CMCs are used for the components of burner and flame holder and the high-temperature gas duct. CMCs are also applied to brake disks, which are subjected to severe thermal shock, and slide bearing parts under heavy loads. The research and development of the CMC are progressed for the strategic purpose in defense and energy industry; for instance, for aerospace applications in the U.S., and for hyper-speed aircraft, gas turbines, and atomic fissions in U.S., Japan, and Europe.