• Title/Summary/Keyword: 복합 사이클

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The Protocol of Basic Body Ability for 4D Cycling System (4D 사이클링에 대한 기초 신체능력 프로토콜)

  • Kim, Ki-Bong;Lee, Sung-Han
    • Journal of Digital Convergence
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    • v.11 no.11
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    • pp.313-320
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    • 2013
  • The four-dimensional cycle simulator, which can recognize whether the road is ascent or descent, its gradient, and status of its surface on Virtual Reality, is introduced in this paper. On the base of these recognitions, various virtual motion path situations are displayed on LCD monitor attached ahead. These various situations may support not only the sense of realty but also an interest in a game in opposition to previous exercise cycles that might be monotonous. In this paper both analysis and estimation of basic bodily abilities for the four-dimensional cycling are addressed.

Overview of Project on COP Increase of Refrigeration Cycle using nano-fluids (나노유체를 이용한 냉동사이클 효율 향상 과제의 소개)

  • Kim, Jeongbae;Lee, Kyu Sun;Lee, Geun An
    • Journal of Institute of Convergence Technology
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    • v.1 no.2
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    • pp.29-32
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    • 2011
  • In this paper, we will introduce the overview of new project dealing how to increase of refrigeration cycle COP using nano-fluids, CuO, TiO2, Al2O3, that are used on similar previous studies. Recently many studies were performed to show the effect of nano-fluids at refrigeration cycle. But, the reason was not cleared yet. In general, the flow phenomena at the evaporator were guessed to be mixed with the partial pool boiling condition and the flow boiling condition from the previous results not published yet. So, we hope that the COP increase of refrigeration cycle will be verified and showed through this project.

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Thermodynamic Analysis of Hybrid Engine Cycle of Brayton and Pulse Detonation Engine (브레이튼과 펄스 데토네이션 복합 엔진 사이클의 열역학적 성능 해석)

  • Kim, Geon-Hong;Koo, Ja-Ye
    • Journal of the Korean Society for Aviation and Aeronautics
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    • v.15 no.1
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    • pp.1-10
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    • 2007
  • When detonation is occurred, the working fluid is compressed itself, though there are no other devices that compress the fluid. As a result, an engine which uses detonation for a combustion process doesn't need moving parts so that the engine can be lighter than other engines ever exist, and such an engine is often referred to as a pulse detonation engine. Since using detonation has higher performance than using deflagration, many studies have been attempting to control and analyze the engines using detonation as combustion. The purpose of this study is to analyze the hybrid cycle which is consisted of Brayton and Pulse Detonation Engine cycle. At first, we set the theoretical basis of detonation analysis, and after that we consider two hybrid cycles; a turbojet hybrid cycle and a turbofan hybrid cycle. The more energy released, the higher detonation Mach number the detonation wave has. In general, a cycle which has a detonation process has higher performances but thermal efficiency of hybrid turbofan engine.

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Conceptual Design of Rocket Based Combined Cycle Engine (Rocket Based Combined Cycle Engine의 개념설계 연구)

  • Lee, Yang-Ji;Kang, Sang-Hun;Yang, Soo-Seok
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2009.11a
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    • pp.581-585
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    • 2009
  • In this study, conceptual design of the RBCC (Rocket Based Combined Cycle) engine was performed for the hypersonic propulsion system development. For the flight mission, RBCC engine takes off at sea level and accelerates up to Mach 8 at the altitude of 30km. By the flight speed characteristics, operating pattern of the engine is categorized into 3 modes : Ejector jet (~Mach 3), Ramjet (Mach 3~6), Scramjet (Mach 6~8). According to the engine mode characteristics, RBCC engine design and analysis was performed.

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TBCC Engine Performance Design Technique of Reusable Launch Vehicle (재사용 우주 발사체의 TBCC 엔진 성능 설계 기법)

  • Kim, Sung-Jin;Sung, Hong-Gye
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2008.11a
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    • pp.167-170
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    • 2008
  • A TBCC(Turbine Based Combined Cycle) engine performance design method for reusable launch vehicles flying both in subsonic and supersonic regime was proposed. The TBCC consists of turbo jet engines and ramjet engines, operating individually or together according to operation schedule. The performance scheme of turbojet and ramjet was validated and the combined engine performance of the TBCC at a typical flight condition was analyzed.

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Performance Analysis on the Multi Stage Reheater Regeneration Cycle for Ocean Geothermal Power Generation (해양지열발전용 다단재열재생사이클 성능해석)

  • Lee, Ho Saeng;Cha, Sang Won;Jung, Young Kwon;Kim, Hyeon Ju
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.17 no.2
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    • pp.116-121
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    • 2014
  • In order to study the improvement of the multi stage regeneration cycles, muti-stage processes were applied to the cycles, respectively or together. The kinds of the cycles are multi stage reheater cycle (MS) and multi stage reheater regeneration cycle (MSR). Working fluid used was R134a and R245fa. Temperature of the heat source was $65^{\circ}C$, $75^{\circ}C$, and $85^{\circ}C$, and temperature of the heat sink was $5^{\circ}C$. Optimization simulation was conducted for improving the gross power and efficiency with multi stage reheater regeneration cycle for ocean thermal energy conversion(OTEC) with changing of a heat source, kind of the working fluid, and type of the cycle. Performance analysis of the various components was simulated by using the Aspen HYSYS for analysis of the thermodynamic cycle. R245fa shows better performance than R134a. This paper showed the most suitable working fluid with changing of a heat source and the kinds of working cycle. Compared to each other, MS showed better performance at gross power and MSR showed higher cycle efficiency.

Electrochemical Characteristics of Si/SiO2/C Anode Material for Lithium-Ion Battery According to Addition of CNT and CNF Compounds (CNT와 CNF 복합첨가에 따른 Si/SiO2/C 음극활물질의 전기화학적 특성)

  • Seo, Jin-Seong;Yoon, Sang-Hyo;Na, Byung-Ki
    • Korean Chemical Engineering Research
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    • v.59 no.1
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    • pp.35-41
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    • 2021
  • Silicon is a promising next-generation anode material for lithium-ion battery, and it has been studied for commercialization due to the high theoretical capacity. However, it has problems of the volume change during charge-discharge and the poor electrical conductivity. To solve these problems, formation of SiO2 and carbon coating on the surface of silicon crystal were performed to protect the side reaction and enhance the electrical conductivity of silicon. CNT and CNF were also added to mitigate the volume change and increase the conductivity. Physical properties of asprepared samples were analyzed by XRD, SEM, and EDS. Electrochemical characteristics were investigated by electrical conductivity measurement, EIS, CV and cycle performance test. (Si/SiO2/C)+CNT&CNF showed high electrical conductivity and low charge-transfer resistance, and the capacity was 1528 mAh/g at 1st cycle and 1055 mAh/g at 50th cycle with 83% capacity retention.

Exergy Analysis of Vapor Compression Cycle Driven by Organic Rankine Cycle (유기랭킨사이클로 구동되는 증기압축냉동사이클의 엑서지 해석)

  • Kim, Kyoung Hoon
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.37 no.12
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    • pp.1137-1145
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    • 2013
  • In this study, exergy analysis of a thermally activated refrigeration cycle, a combined organic Rankine cycle (ORC), and a vapor compression cycle (VCC) were conducted. It is considered that a system uses a low-temperature heat source in the form of sensible heat, such as various renewable energy sources or waste heat from industries, and one of eight working fluids: R143a, R22, R134a, propane, isobutane, butane, R245fa, or R123. The effects of turbine inlet pressure and the working fluid selected on the exergy destructions (anergies) at various system components as well as the COP and exergy efficiency of the system were analyzed and discussed. The results show that the component of the greatest exergy destruction in the system varies sensitively with the turbine inlet pressure and/or working fluid.

Electrochemical Characteristics of Electrolyte Additives and Nano-Pb/AC Anode for Ultra Batteries (울트라 배터리 용 전해액 첨가제와 Nano-Pb/AC 음극의 전기화학적 특성)

  • Kim, Geun Joong;Lee, Jong Dae
    • Applied Chemistry for Engineering
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    • v.29 no.5
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    • pp.549-555
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    • 2018
  • In this study, the electrochemical properties of nano-Pb/activated carbon (nano-Pb/AC) composites and electrolyte additives were examined to improve the performance of ultra batteries. Physical properties of the prepared nano-Pb/AC composites were analyzed using FE-SEM, TEM, XPS and BET. The electrochemical performances of ultra batteries were performed by cycle, rate performance and impedance tests. The cycling performance of nano-Pb/AC (Pb : 9 wt%) coated ultra battery increased by 150% with respect to the lead acid one, and the discharge specific capacity increased by 119-122% for 1-5 C rate tests. As a result of the impedance test, it was confirmed that the internal resistance decreased as the nano lead content increased. The cycle performance of the ultra battery containing 0.45 vol% electrolyte additives showed 140% longer than that of no electrolyte additives.

Measurement of CTE Change in a Composite Laminate with Aging under Space Environment using Fiber Optic Sensors (광섬유센서를 이용한 우주환경하에서 복합재료 적층시편의 노화에 따른 열팽창계수변화 측정)

  • Gang,Sang-Guk;Gang,Dong-Hun;Kim,Cheon-Gon;Hong,Chang-Seon
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.31 no.10
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    • pp.21-26
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    • 2003
  • In this research, the change of coefficient of thermal expansion (CTE) of graphite/epoxy composite laminate under space environment was measured using fiber optic sensors. Two fiber Bragg grating (FBG) sensors have been adopted for the simultaneous measurement of thermal strain and temperature. Low Earth Orbit (LEO) conditions with high vacuum, ultraviolet and thermal cycling environments were simulated in a thermal vacuum chamber. As a pre-test, a FBG temperature sensor was calibrated and a FBG strain sensor was verified through the comparison with the electric strain gauge (ESG) attached on an aluminun specimen at high and low temperature respectively. The change of the CTE in a composite laminate exposed to space environment was measured for intervals of aging cycles in real time. As a whole, there was no abrupt change of the CTE after 1000 aging cycles. After aging, however, the CTE decreased a Little all over the test temperature range. These changes are caused by outgassing, moisture desorption, matrix cracking etc.