• Title/Summary/Keyword: GRI

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Simulation of Methane Swirl Flame in a Gas Turbine Model Combustor (가스터빈 모사 연소기에서 선회 확산 화염의 연소특성 해석)

  • Joung, Dae-Ro;Huh, Kang-Yul
    • 한국연소학회:학술대회논문집
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    • 2007.05a
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    • pp.118-125
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    • 2007
  • The firtst-order conditional moment closure (CMC) model is applied to CH4/air swirl diffusion flame in a gas turbine model combustor. The flow and mixing fields are calculated by fast chemistry assumption with SLFM library and a beta function pdf for mixture fraction. RNG k-e model is used to consider the swirl flame in a confined wall. Reacting scalar fields are calculated by elliptic CMC formulation with chemical kinetic mechanism, GRI Mech 3.0. Validation is done against measurement data for mean flow and scalar fields in the model combustor [1]. Results show reasonable agreement with the mean mixture fraction and its variance, while temperature is overpredicted as the level of local extinction increases. The second-order CMC model is needed to consider local extinction with considerable conditional fluctuations near the nozzle.

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Comparison of the combustion characteristics between air combustion and oxy-combustion with $CO_2$ recirculation ($CO_2$ 재순환에 의한 순산소 연소와 공기 연소의 화염 특성 비교)

  • Lee, Seung-Hwan;Huh, Kang-Y.
    • Journal of the Korean Society of Combustion
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    • v.13 no.3
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    • pp.24-32
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    • 2008
  • Steady Laminar Flamelet Model (SLFM) calculation is performed to compare the turbulent combustion characteristics of air combustion and oxy-combustion with $CO_2$ recirculation. Radiative heat loss is considered by the optically thin limit assumption. For more realistic simulation the first-order conditional moment closure(CMC) model is applied to SANDIA PILOTED FLAME D again for the oxidants of air and mixture of $O_2$ and $CO_2$. The chemical kinetic machanism for methane is GRI Mech 3.0. Results show that oxy flames are much more stable than air flames, while comparable stability is maintained with 65% $CO_2$ recirculation. The comparable peak temperature is maintained with 80% $CO_2$ recirculation. Higher the temperature, higher the fractions of intermediate species, CO and OH, due to dissociation.

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Radiation Effects on the Flame Structure and Extinction Limit of Counterflow Partially Premixed Methane Flames Diluted with Water Vapor in the Air Stream (공기류측에 수증기가 첨가된 대향류 메탄 부분예혼합화염의 화염구조 및 소화한계에 미치는 복사효과)

  • Park, Ji-Woong;Oh, Chang Bo;Kim, Ook Joong
    • 한국연소학회:학술대회논문집
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    • 2012.11a
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    • pp.325-328
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    • 2012
  • Radiation effects on the partially premixed methane flames diluted with water vapor in the air stream were numerically investigated. OPPDIF code and GRI-v3.0 were used in the numerical simulation. Adiabatic condition was compared with two different radiation models, optically-thin and WSGGM models. It was found that the radiation effect on the flame structure for the equivalence ratio (${\Phi}$) of 2.5 was less than ${\Phi}=1.5$. Extinction limit was not affected significantly, however, local flame structure was markedly influenced by the radiation models as increasing the water vapor concentration.

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Variation of oxygen-enriched flame characteristics with dilution method (산소부화화염의 희석방법에 따른 화염특성 변화)

  • Han, Ji-Woong;Lee, Chang-Eon
    • Proceedings of the KSME Conference
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    • 2003.11a
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    • pp.332-337
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    • 2003
  • Oxygen-enriched non-premixed flame characteristics was investigated numerically with variation of dilution methods, which are Flue gas recirculation(FGR) and fuel injection recirculation(FIR). In order to compare flamelets in various oxygen-enrichment conditions reasonably, the adiabatic flame temperature and Damkoller number was held fixed by modulating amount of diluents to fuel and oxidizer stream and by varying global strain rate of flame respectively. Also modified GRI 3.0 reaction mechanism was utilized, which was able to predict oxygen-enriched methane flame correctly. Fundamental flame characteristics such as structure, heat release rate and extinction with FGR and FIR were compared in various oxygen enrichment conditions.

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Interaction Mode Change According to the Equivalence Ratios in the Interacting Methane and Hydrogen Counterflow Premixed Flames (상호작용하는 대향류 메탄 및 수소 예혼합화염에서 당량비 조건에 따른 상호작용 모드 변화)

  • Park, Ji-Woong;Oh, Chang Bo
    • 한국연소학회:학술대회논문집
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    • 2012.04a
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    • pp.13-16
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    • 2012
  • The interaction between methane and hydrogen premixed flames with the different equivalence ratio and global strain rate was investigated numerically in one-dimensional counterflow field. The OPPDIF code and GRI-v3.0 were used to simulate the interacting flames. Overall trends in the maximum heat release rates of $CH_4{^-}$ and $H_2$-side flame were examined with the variation of $a_g$. The interaction mode of the flames were classified according to the equivalence ratios and Lewis numbers of each flame and global strain rate.

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A study for International Guidelines for Corporate Social Responsibility and Corporate Reporting for Sustainable Development (기업의 사회적 책임 기준과 기업 보고에 관한 고찰)

  • Kim, Gwang-Sub;Lee, Byung-Yong
    • Journal of Korean Society for Quality Management
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    • v.35 no.3
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    • pp.47-54
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    • 2007
  • CSR(Corporate Social Responsibility) is the subject which has been discussed for a long time, but real preparations of the corporations begin recently. International organizations and global corporation councils have announced their own guidelines about CSR The corporations have to establish responsible departments in their organizations and begin to publish reports which deals with the social responsibility. GRI(Global Reporting Initiative) have launched international guideline for corporate reporting and ISO has progressed making international standard for CSR. This paper is a study about understanding the international regulations tendency of CSR and the trend of Corporate Reporting for their sustainable development of the organizations.

Strategic Management Audit to Government-sponsored Research Institutes : A Case of Korea Basic Science Institute (KBSI) (정부출연연구기관의 전략적 경영감사 : 한국기초과학지원연구원의 사례를 중심으로)

  • Chung Sun-Yang;Park Jeong-Soo;Gim In-Ho;Cho Sung-Bok
    • Journal of Korea Technology Innovation Society
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    • v.8 no.2
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    • pp.832-859
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    • 2005
  • Government-sponsored Research Institutes (GRIs) have made a great contribution to the development of Korea's Science and Technology (S&T). However, recently, GRIs are facing the challenge of many problems, for instance, absence of reasonable strategies, insufficient resources, and so on. Therefore, many GRIs are required for solving these problems by enhancing their strategic management capabilities. For this purpose, this paper suggests a Strategic Management Audit Model for Korean GRIs. The concept of Strategic Management Audit Model has not been widely adopted in Korean GRIs. In this paper, we suggest GRI-specific Strategic Management Model and apply it to Korea Basic Science Institute (KBSI), which is under the Korea Research Council of Fundamental Science and Technology (KRCF). Based on our strategic management audit, we propose several potential strategies for Korean Basic Research Institutes (KBSI). Our model and its implications will also be helpful for other Korean GRIs.

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A Study on Business Ethics of Competitive Superiority Strategy (경쟁우위 전략에서의 기업윤리에 관한 연구)

  • Yim, Woong-Seok;Kim, Hyung-Joon;Lee, Nae-Hyung
    • Journal of the Korea Safety Management & Science
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    • v.9 no.1
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    • pp.157-174
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    • 2007
  • Corporation had been made by important action rule of business ethics that observes legal standard that is prescribed in each class of administration activity. But it does not keep ethicality of corporation action that conforms law. Law can not include all parts of business ethics because it is forcing essential class for public order preservation and public welfare in right. Moreover, partial corporations are doing to justify unethical action of other evasion of taxes, consultation, manufacturing etc. with legal basis meaning abusing legal standard. For these reason, Insistence that is in point of legal standard and ethical standard is not different each other that is in equal viewpoint is brought.

The impact of open innovation activities on performance of Korean IT SMEs·Venture: Technology Transfer Experiences and Technological Collaborations (중소·벤처기업의 개방형혁신 노력이 성과에 미치는 영향에 관한 연구: 기술이전경험과 기술협력유형을 중심으로)

  • Roh, Doo-Hwan;Hwang, Kyung-Ho;Park, Ho-Young
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
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    • v.12 no.1
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    • pp.33-46
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    • 2017
  • In Korea, small and medium sized domestic enterprises (SMEs) play an pivotal role in the national economy, accounting for 99.8% of all enterprises, 87.9% of total employment, and 48.3% of production. and SMEs were driving a real force of the development of national economy in many respects such as innovation, job creation, industrial diversity, balanced regional development. Despite their crucial role in the national development, most of SMEs suffer from a lack of R&D capabilities and equipments as well as funding capacity. Government-Supported Research Institute (GRI) can provide SMEs with valuable supplementary technological knowledges and help them build technological capacities. so, In order to effectively support SMEs, government and GRI must be a priority to know about the factors influencing the performance related to technology transfer and technological collaborations. The paper analyzes the effects of Korean IT SMEs Venture external collaborations and technology transfer on their performances, according to their collaboration activities and technology transfer experiences. The results show that there was a significant difference between '3~5times' of technology transfer experience and 'zero technology transfer experience' in the case of technology transfer experience. In case of technological collaboration type, there was a significant difference between 'R&D manpower' and 'enhancement of technological capabilities including core technologies'. The results show that the effectiveness of technology transfer of Korean IT SMEs Venture depends on experiences, types of collaboration activities. so the results of this research will be useful for Government-Supported research institute (GRI)' policy makers when establishing technology commercialization support policies and strategic planning of small and medium sized domestic enterprises.

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Analysis of Long-Term Performance of Geogrids by Considering Interaction among Reduction Factors (감소계수 상호영향을 고려한 지오그리드의 장기성능 해석)

  • Jeon, Han-Yong;Kim, Yuan-Chun;Jang, Yeon-Soo
    • Journal of the Korean Geotechnical Society
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    • v.28 no.7
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    • pp.55-65
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    • 2012
  • Total reduction factor that is used when calculating allowable tensile strength of geogrids is made by multiplying the installation damage reduction factor ($RF_{ID}$), chemical degradation reduction factor ($RF_D$), and creep reduction factor ($RF_{CR}$) etc. In case of a model estimating allowable tensile strength considering reduction factor over the short-term tensile strength of geogrids, it has a limit of not considering interaction force between reduction factors. Junction strength comes to be reduced by installation damages or chemical degradation in the same way as tensile strength. Single junction test method cannot properly test damaged samples and shows large deviations as it does not consider scale effect. Besides, regarding calculating shear strength, no reasonable study on reduction factors was conducted yet. Therefore, in this study, reduction factors that may affect the long-term performance of geogrids were revaluated considering various conditions and accurate long-term allowable tensile strength was calculated considering interrelation between reduction factors. Creep results after installation damage and chemical resistance test showed lower value than calculated value according to GRI GG-4. After the installation damage test and the chemical resistance test, the reduction factor of junction strength was less than that of tensile strength. Shear strength before and after installation damage showed no change or increase.