• Title, Summary, Keyword: Fast burning

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Part Load Performance Characteristics according to Inlet Valve Angle (흡입 밸브 각도에 따른 엔진 부분부하 성능 특성)

  • Lee, Jung-Man;Lee, Jae-Won;Kim, Hyeong-Sig;Kwon, Soon-Tai;Park, Chan-Jun;Ohm, In-Yong
    • Proceedings of the Korea Society for Energy Engineering kosee Conference
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    • pp.161-166
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    • 2008
  • This paper searched through mixture ratio response test whether exert effect that is some in part load performance of engine according to inlet valve angle in gasoline engine. Engines that inlet valve angle is narrow decreased quantity of NOx among exhaust gas than engine that inlet valve angle is wide, and ignition timing was retard, and fuel consumption improved a little. That quantity of NOx among exhaust gas decreases and ignition timing was retard can judge that fast burning occurred. Fast burning can decrease output decline and misfire that can happen at lean burning. Can be judged by thing which engine's combustion performance improves if inlet valve angle is narrow if examine test result.

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A Study on Relationship between Ignition Systems and the Performances of Gasoline Engines (I) (점화시스템의 종류와 가솔린 엔진 성능과의 상관관계에 대한 연구 (I))

  • SunWoo, Myoung-Ho;Song, Jeong-Hoon
    • Proceedings of the KIEE Conference
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    • pp.966-969
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    • 1998
  • Fast burning achieves higher efficiency, and reduces cycle variations which is able to improve vehicle driveability. Furthermore, the greater resistance to knock with fast burning can allow the fuel economy advantages associated with higher compression ratio to be realized. One way of increasing the combustion speed is to enhance the performance of ignition systems which were able to reduce the early period of combustion. It is well known that shortening the initial stage of combustion also reduces the cyclic variations. This literature survey deals with the papers which have studied the ignition process or various ignition systems. Those systems increasing the combustion speed, extending the lean misfire limit, reducing the exhaust gas and stabilizing the operating condition of the spark ignition engine by modifying the ignition process or increasing ignition energy.

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A Mathematical Model for Pyrolysis Processes During Unforced Smoldering of Cigarette (비흡입시 연소하는 담배의 열분해 작용에 관한 수학적 모델)

  • 이성철
    • Journal of the Korean Society of Tobacco Science
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    • v.17 no.2
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    • pp.160-169
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    • 1995
  • A mathematical model for the pyrolysis processes during unforced smoldering of cigarette was proposed in this study by analyzing the physical model of the smoldering cigarette (including the establishment of burning front between burning zone and pyrolysis zone, and analyzing the involvement of main factors such as pyrolysis of virgin tobacco, evaporation of water, and internal heat transport in the processes). Thermal conduction of cigarette paper and convective and radiative heat transfer at the outer surface were also considered via the thermal resistance law for the competitive heat transfer mechanisms. The governing partial differential equations were solved using an integral method. Model predictions of smoldering speed, or linear burn rate, as well as temperature and density profiles in the pyrolysis zone for different kinds of cigarettes were found to be close to the experimental data in the literature (Muramatsu, 1981). The model provides a relatively fast and efficient way to simulate the pyrolysis processes and offers a practical tool for exploring important parameters for a smoldering cigarette, such as blended tobacco composition, properties of cigarette paper, and heat flux from the burning zone to the pyrolysis zone.

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FAST REACTOR PHYSICS AND COMPUTATIONAL METHODS

  • Yang, W.S.
    • Nuclear Engineering and Technology
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    • v.44 no.2
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    • pp.177-198
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    • 2012
  • This paper reviews the fast reactor physics and computational methods. The basic reactor physics specific to fast spectrum reactors are briefly reviewed, focused on fissile material breeding and actinide burning. Design implications and reactivity feedback characteristics are compared between breeder and burner reactors. Some discussions are given to the distinct nuclear characteristics of fast reactors that make the assumptions employed in traditional LWR analysis methods not applicable. Reactor physics analysis codes used for the modeling of fast reactor designs in the U.S. are reviewed. This review covers cross-section generation capabilities, whole-core deterministic (diffusion and transport) and Monte Carlo calculation tools, depletion and fuel cycle analysis codes, perturbation theory codes for reactivity coefficient calculation and cross section sensitivity analysis, and uncertainty analysis codes.

A NEXT GENERATION SODIUM-COOLED FAST REACTOR CONCEPT AND ITS R&D PROGRAM

  • Ichimiya, Masakazu;Mizuno, Tomoyasu;Kotake, Shoji
    • Nuclear Engineering and Technology
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    • v.39 no.3
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    • pp.171-186
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    • 2007
  • Critical issues in the development targets for the future fast reactor(FR) cycle system, including sodium-cooled FR were to ensure safety assurance, efficient utilization of resources, reduction of environmental burden, assurance of nuclear non-proliferation, and economic competitiveness. A promising design concept of sodium-cooled fast reactor JSFR is proposed aiming at fully satisfaction of the development targets for the next generation nuclear energy system. A roadmap toward JSFR commercialization is described, to be followed up in a new framework of the Fast reactor Cycle Technology development(FaCT) Project launched in 2006.

Change of Surface Temperature in Woodceramics Made from MDF(I) -Effect of Density and Burning Temperature- (MDF로 제조된 우드세라믹의 표면온도변화(I) -밀도 및 소성온도의 영향-)

  • 오승원
    • Journal of Korea Foresty Energy
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    • v.21 no.1
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    • pp.1-6
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    • 2002
  • The following conclusions were obtained with measuring the surface temperature change of woodceramics which were made of MDF to identify usability of using them as a sub-material for heating system when installing Ondol heating floor. For this purpose, woodceramics were burned at the temperature of $650^{\circ}C$ and $800^{\circ}C$ 1. Surface temperature of woodceramics increased with the increase of density of woodceramics, but no significant difference was detected at the surface temperature when burning temperature was changed. 2. Surface temperature change under given temperature increased as time passed and it showed more increase in temperature at the burning temperature of 80$0^{\circ}C$. 3. Surface temperature change with the change in floor temperature increased u hen floor temperature increased and heating mechanism was fast with increase of measuring temperature.

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Storage Lifetime Improvement of Zr-Ni K1 Delay System (Zr-Ni계 지연관 결합체(K1) 저장수명 향상)

  • Chang, Il-Ho;Back, Seung-Jun;Jung, Eun-Jin;Son, Young-Kap
    • Journal of the Korea Institute of Military Science and Technology
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    • v.13 no.2
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    • pp.336-341
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    • 2010
  • The burning interruption between the initiator and the delay column in a Zr-Ni K1 delay system used for a K510 fuze occurs with long-time storage. About 10 % failure probability of 15-years stored delay systems shows the failure mode in open literature. This paper shows storage lifetime improvement results for the delay system through changing the single-base delay column into double-base ones and controlling the manufacturing processes especially the initial inclusion of humidity. The double-base delay columns was implemented by inserting one delay column of fast burning rates between the initiator and the previous delay column of slow burning rates. Accelerated aging tests of the delay systems with double-base columns, and then the firing tests were performed to evaluate the improved lifetime. The double-base delay columns shows improved storage lifetime of the delay system through preventing the failure mode.

Parameter Effects on the Time to Reach Flashover Conditions in Single Room Fires (건물화재의 플래시오버 도달 시간에 영향을 미치는 인자들에 관한 연구)

  • Kim, Hyeong-Jin;Lilley, David-G.;Baek, Byung-Joon;Pak, Bock-Choon
    • Proceedings of the KSME Conference
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    • pp.1384-1388
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    • 2003
  • In structural fires, flashover is characterized by the rapid transition in fire behavior from localized burning of fuel to the involvement of all combustibles in the enclosure. An investigation of parameter effects on the time to reach flashover conditions in a typical single room fire is undertaken using a zone method (FAST) and Thomas method. Major parameters affecting the time to reach flashover are found to be fire growth rate, ventilation opening area and internal room surface. The results of the FAST and the Thomas Method give very similar results of the time to reach flashover..

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Overall System Description and Safety Characteristics of Prototype Gen IV Sodium Cooled Fast Reactor in Korea

  • Yoo, Jaewoon;Chang, Jinwook;Lim, Jae-Yong;Cheon, Jin-Sik;Lee, Tae-Ho;Kim, Sung Kyun;Lee, Kwi Lim;Joo, Hyung-Kook
    • Nuclear Engineering and Technology
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    • v.48 no.5
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    • pp.1059-1070
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    • 2016
  • The Prototype Gen IV sodium cooled fast reactor (PGSFR) has been developed for the last 4 years, fulfilling the technology demonstration of the burning capability of transuranic elements included in light water reactor spent nuclear fuel. The PGSFR design has been focused on the robustness of safety systems by enhancing inherent safety characteristics of metal fuel and strengthening passive safety features using natural circulation and thermal expansion. The preliminary safety information document as a major outcome of the first design phase of PGSFR development was issued at the end of 2015. The project entered the second design phase at the beginning of 2016. This paper summarizes the overall structures, systems, and components of nuclear steam supply system and safety characteristics of the PGSFR. The research and development activities to demonstrate the safety performance are also briefly introduced in the paper.

Measurement of fast ion life time using neutron diagnostics and its application to the fast ion instability at ELM suppressed KSTAR plasma by RMP

  • Kwak, Jong-Gu;Woo, M.H.;Rhee, T.
    • Nuclear Engineering and Technology
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    • v.51 no.7
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    • pp.1860-1865
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    • 2019
  • The confinement degradation of the energetic particles during RMP would be a key issue in success of realizing the successful energy production using fusion plasma, because a 3.5 MeV energetic alpha particle should be able to sustain the burning plasma after the ignition. As KSTAR recent results indicate the generation of high-performance plasma(${\beta}_p{\sim}3$), the confinement of the energetic particles is also an important key aspect in neutral beam driven plasma. In general, the measured absolute value of the neutron intensity is generally used for to estimating the confinement time of energetic particles by comparing it with the theoretical value based on transport calculations. However, the availability of, but for its calculation process, many accurate diagnostic data of plasma parameters such as thermal and incident fast ion density, are essential to the calculation process. In this paper, the time evolution of the neutron signal from an He3 counter during the beam blank has permitted to facilitate the estimation of the slowing down time of energetic particles and the method is applied to investigate the fast ion effect on ELM suppressed KSTAR plasma which is heated by high energy deuterium neutral beams.