• Title/Summary/Keyword: 가스냉각

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Modeling of Gasifier with PRO/II (PRO/II를 사용한 가스화기 모델링)

  • Kim, KwangSin;Joo, Yong-Jin;Kim, Mi Yeong;Kim, Si-Moon;Lee, Joongwon;Kim, Ki-Tae
    • 한국신재생에너지학회:학술대회논문집
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    • 2010.11a
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    • pp.131.2-131.2
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    • 2010
  • 서부 발전 태안화력발전소에 건설 예정인 IGCC Demo plant의 설계 자료를 근거로 석탄 가스화기의 정상 상태 전산모사를 PRO/II를 사용하여 수행하였다. 석탄을 PRO/II가 받아들일 수 있는 성분으로 바꾼 후 가스화기를 버너와 가스화기 본체의 두 부분으로 나누어 모델링하였다. 버너는 단열조건의 Gibbs Reactor로 모델링하였다. 모사 결과 산소가 완전 소진될 때까지 반응이 진행되는 것을 확인하였다. 가스화기는 char gasification 반응은 kinetic reaction equation으로, gas phase reaction은 equilibrium reactor로 모사하는 알고리듬을 개발 하였으나 PRO/II의 기능에 한계가 있어 간단한 Gibbs Reactor로 모사하였다. 가스화기는 membrane wall에 의하여 냉각되는 것을 고려하여 $1550^{\circ}C$의 균일한 온도에서 반응이 일어나는 것으로 고려하였다. 전산 모사 결과 주요 성분의 조성이 실제 syngas의 조성과 5% 정도 오차가 있는 것으로 나타났다.

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Conceptual Design of Coolant Channel for Sub-scale Combustion Chamber (소형 연소기 냉각 유로 개념 설계)

  • 정용현;조원국;한상엽;류철성
    • Journal of the Korean Society of Propulsion Engineers
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    • v.6 no.4
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    • pp.1-6
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    • 2002
  • A numerical heat transfer analysis and the structural analysis were performed for the design of sub-scale combustion chamber's coolant passage. The heat flux through the combustion chamber wall was estimated by 2-D heat transfer analysis of compressible hot gas and the result was applied as a thermal boundary condition of 3-D analysis. The heat flux estimated by the present method agreed well with the experimental correlation and proved to be insensitive to cooling condition. So the same thermal boundary condition was applied for various operating conditions. The maximum temperature of combustion chamber wall was predicted by 3-D analysis for single coolant passage and the result will be used for the development of a regeneratively cooled combustion chamber. Also estimated were the stress distribution and structural safety of coolant passage through the static structural analysis.

A study on the reduction of emission by controlled cooling system in a diesel engine (냉각 시스템 제어에 따른 디젤 엔진의 배기가스 저감에 관한 연구)

  • Choi, Kyung-Wook;Cho, Won-Joon;Lee, Ki-Hyung
    • Proceedings of the KSME Conference
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    • 2007.05b
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    • pp.3294-3299
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    • 2007
  • These days the exhaustion of petroleum resources and environmental problems are getting serious. Many researchers are focused on low emission and high performance vehicles. Therefore, we should concern about emission regulation when we design a new car. In this study, we investigated the characteristics of the traditional mechanical engine cooling systems which control the engine temperature using engine speed and wax type thermostat. This experiment used three components which are Radiator fan, water pump and water valve controlled by an electronic system based on the engine status (load, speed). We elucidated how different between traditional mechanical cooling system and electronic cooling system which control coolant temperature and coolant flow rate in a DI diesel engine in this paper. The results revealed a fuel saving and an emission (CO, HC) reduction on NEDC cycle.

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Structural Analysis of Gas Generator Regenerative Cooling Chamber (재생냉각형 가스발생기 챔버 구조해석)

  • Ryu, Chul-Sung;Kim, Hong-Jip;Choi, Hwan-Seok
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.31 no.10
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    • pp.1046-1052
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    • 2007
  • Elastic-plastic structural analysis for regenerative cooling chamber of gas generator was performed. Uniaxial tension test was conducted for STS316L at room and high temperature conditions to get the material data necessary for the structural analysis of the chamber which was operated under thermal load and high internal pressure. Physical properties including thermal conductivity, specific heat and thermal expansion were also measured. The structural analysis for four different types of regenerative cooling chamber of gas generator revealed that increased cooling performance decreased the thermal load and strain of the cooling channel structure. The results propose that in order for the regenerative cooling gas generator chamber to have high structural stability with endurance to high mechanical and thermal loads, it is important for the chamber to be designed to have high cooling performance.

A Numerical Study on the Film-Cooling Characteristics of Gas Turbine Blade using CO2 (이산화탄소를 이용한 가스터빈 블레이드 막냉각 특성 연구)

  • Kim, Sang-Gwon;Lee, Jong-Chul;Kim, Youn-Jea
    • The KSFM Journal of Fluid Machinery
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    • v.15 no.2
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    • pp.41-44
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    • 2012
  • In order to cool the turbine blade under high temperature operating conditions, the film-cooling method is generally applied. In this study, $CO_2$ was used as working fluid and it helped the operating system to prevent the loss of compressed air. The trapezoidal diffuser shape was adopted at the cross section of hole and the characteristics of heat flow with various working fluids were numerically studied. In particular, the different mixture ratios of $CO_2$, such as various density ratios of 0.2, 0.8, and 1.0, respectively, were considered. Numerical results are graphically depicted with various conditions.

Evaluation of Thermal Fluid Characteristics for EGR Cooler with Spiral Type (Spiral 구조 EGR Cooler의 열유동 특성 평가)

  • 허형석;원종필;박경석
    • Transactions of the Korean Society of Automotive Engineers
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    • v.11 no.6
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    • pp.44-50
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    • 2003
  • Cooled EGR is an effective method for the reduction of NOx from a diesel engine and an EGR Cooler is the key component of the system. High efficiency, low pressure loss and compactness are required for the EGR Cooler. To meet these requirements, new geometric tube must be developed. In this paper, a full size EGR cooler test bench has been developed to validate the CFD flow and heat transfer models. Fluid temperature and pressure drop measurements are provided. fillet temperature is $200^{\circ}C$ and $300^{\circ}C$, and flow rates vary from 0.008 kg/sec to 0.019 kg/sec. The gas flow and heat transfer in a single tube cooler have been studied using computational fluid dynamics(CFD). Analysis has been carried out in a single tube with a plain tube and six spirally enhanced tubes of varying pitch to depth ratio(p/e).

Structural Analysis of Gas Generator Regenerative Cooling Chamber (가스발생기 재생냉각 챔버 구조해석)

  • Ryu, Chul-Sung;Choi, Hwan-Seok
    • Proceedings of the KSME Conference
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    • 2007.05a
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    • pp.802-807
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    • 2007
  • Elastic-plastic structural analysis for regenerative cooling chamber of gas generator was performed. Uniaxial tension test was also conducted for STS316L at room and high temperature conditions to get the material data necessary for the structural analysis of the chamber which is operated under thermal load and high internal pressure. Physical properties including thermal conductivity, specific heat and thermal expansion data were also measured. The structural analysis for four different types of regenerative cooling chamber of gas generator revealed that increased cooling performance decreases the thermal load and strain of the cooling channel. The results propose that in order for the regenerative cooling gas generator chamber to have high structural stability with endurance to high mechanical and thermal loads, it is important for the chamber to be designed to have high cooling performance.

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Heat Transfer Analysis of EGR Cooler with Different Tube Shape (튜브형상에 따른 배기가스 재순환 냉각 장치 열전달 성능 평가)

  • Sohn, Chang-Hyun
    • Transactions of the Korean Society of Automotive Engineers
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    • v.15 no.5
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    • pp.112-117
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    • 2007
  • With the Euro-4 regulation coming into effect, the domestic car industry is forced to look for newer options to reduce NOX in the exhaust. EGR(Exhaust Gas Recirculation) Cooler is an effective method for the reduction of NOX form a diesel engine. High efficiency, low pressure loss and compactness are desirable features of an EGR Cooler. The cooling performance of EGR depends on the shape of tubes and the location of the entrance and exit. This paper reports the computational work conducted to estimate the performance of EGR cooler with three different cross section tubes and a triangular spiral tube. Three dimensional computation results show that the triangular tube is more effective than circular and rectangular tube. The most effective geometry is a triangular spiral tube with offset inlet and outlet locations.

Performance Simulation of Natural Circulating Cooling System of SF6 Gas Charged Transformer (SF6 가스를 충전한 변압기의 자연순환 냉각시스템의 성능시뮬레이션)

  • Choi, Y.D.;Huh, C.S.;Kim, J.G.
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.6 no.1
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    • pp.54-65
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    • 1994
  • Performance of naturally circulating cooling system of $SF_6$ gas charged transformer was simulated and the variations of gas flow rate, maximum coil temperature, gas temperature and cooling air temperature were investigated with respect to the height of radiator, interplates distance and heat generation rate at core. The results show that the height of radiator most significantly affects the performance of natural circulating cooling system of transformer.

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DESIGN OPTIMIZATION OF UPPER PLENUM OF PBMR USING RESPONSE SURFACE APPROXIMATION (반응면기법을 이용한 PBMR 기체냉각형 고온가스로 상층부의 최적설계)

  • Lee, S.M.;Kim, K.Y.
    • 한국전산유체공학회:학술대회논문집
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    • 2010.05a
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    • pp.187-194
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    • 2010
  • Shape optimization of an upper plenum of PBMR type gas cooled nuclear reactor has been performed by using three-dimensional Reynolds-Averaged Navier-Stokes (RANS) analysis and surrogate modeling technique. The objective function is defined as a linear combination of uniformity of flow distribution in the core and pressure drop in the upper plenum and the core. The ratio of thickness of slot to diameter of rising channels, ratio of height of upper plenum to diameter of rising channels, and ratio of eight of the slot at inlet to outlet, are used as design variables for optimization. Design points are selected through Latin-hypercube sampling. The optimal point is determined through surrogate-based optimization method which uses 3-D RANS analyses at design points. The results show that the optimum shape represent remarkably improved performance in flow uniformity and friction loss than the reference shape.

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