• 제목/요약/키워드: hybrid model

검색결과 2,524건 처리시간 0.039초

복합 모델을 이용한 연료 인젝터의 분무 미립화 모델링 (Modeling of Spray Atomization of Fuel Injector Using Hybrid Model)

  • 박성욱;김형준;류열;이창식
    • 한국자동차공학회논문집
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    • 제10권6호
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    • pp.27-33
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    • 2002
  • This paper presents the comparison of prediction accuracy of hybrid models. To obtain the experimental results fur comparing with the numerical results, the macroscopic and microscopic structures of the hollow-cone spray such as spray development process, spray penetration and the distribution of mean droplet size are investigated by using a shadowgraph technique and phase Doppler particle analyzer. Also, the numerical researches using various hybrid models are performed. LISA model and WAVE model are used for the primary breakup, and TAB, DDB, and RT model are used for the secondary breakup.

A hybrid numerical simulation method for typhoon wind field over complex terrain

  • Huang, Wenfeng;Zhou, Huanlin
    • Wind and Structures
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    • 제18권5호
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    • pp.549-566
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    • 2014
  • In spite of progress in the numerical simulation of typhoon wind field in atmospheric boundary layer (ABL), using typhoon wind field model in conjunction with Monte Carlo simulation method can only accurately evaluate typhoon wind field over a general terrain. This method is not enough for a reliable evaluation of typhoon wind field over the actual complex terrain with surface roughness and topography variations. To predict typhoon wind field over the actual complex terrain in ABL, a hybrid numerical simulation method combined typhoon simulation used the typhoon wind field model proposed by Meng et al. (1995) and CFD simulation in which the Reynolds averaged Navier-Stokes (RANS) equations and k-${\varepsilon}$ turbulence model are used. Typhoon wind filed during typhoon Dujuan and Imbudo are simulated using the hybrid numerical simulation method, and compared with the results predicted by the typhoon wind field model and the wind field measurement data collected by Fugro Geotechnical Services (FGS) in Hong Kong at the bridge site from the field monitoring system of wind turbulence parameters (FMS-WTP) to validate the feasibility and accuracy of the hybrid numerical simulation method. The comparison demonstrates that the hybrid numerical simulation method gives more accurate prediction to typhoon wind speed and direction, because the effect of topography is taken into account in the hybrid numerical simulation method.

직렬-복합소호형 모델 가스차단기의 차단성능평가 (Estimation of Interruption Capability of a Serial-Hybrid Type Model Gas Circuit Breaker)

  • 송기동;정진교;박경엽
    • 대한전기학회논문지:전기기기및에너지변환시스템부문B
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    • 제53권9호
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    • pp.538-544
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    • 2004
  • This paper presents the interruption capability of serial-hybrid type GCB (gas circuit breaker) compared with that of puffer type. First a puffer type model interrupter which has the stroke length of 80 mm has been designed and manufactured. And also, a serial-hybrid type interrupter which has the same design parameters as the puffer type interrupter except the serially arranged thermal-expansion chamber and puffer cylinder has been fabricated. Using a simplified synthetic test facility, the critical interruption capabilities of the two GCBs have been estimated. The critical di/dt, the critical dV/dt of ITRV (initial transient recovery voltage) and the minimum arcing time of the puffer type model GCB were 10.7 A/${\mu}\textrm{s}$, 5.5 kV/${\mu}\textrm{s}$, and 15.0 ms respectively. In the case of serial-hybrid type model GCB, each of the values was 16.6A/${\mu}\textrm{s}$, 11.5 kV/${\mu}\textrm{s}$ and 13.0 ms. As a conclusion of this work, it has been quantitatively confirmed that the hybrid type interrupter can obtain the sufficient interruption capability at the operating force which is so low that puffer type interrupter has not the interruption capability.

최소 자승법을 이용한 하이브리드용 리튬이온 배터리 모델링 및 특성분석 (Modeling and Characteristic Analysis of HEV Li-ion Battery Using Recursive Least Square Estimation)

  • 김호기;허상진;강구배
    • 한국자동차공학회논문집
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    • 제17권1호
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    • pp.130-136
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    • 2009
  • A lumped parameter model of Li-ion battery in hybrid electric vehicle(HEV) is constructed and system parameters are identified by using recursive least square estimation for different C-rates, SOCs and temperatures. The system characteristics of pole and zero in frequency domain are analyzed with the parameters obtained from different conditions. The parameterized model of Li-ion battery indicates highly dependant of temperatures. The system pole and internal resistance changes 6.6 and 18 times at $-20^{\circ}C$, comparing with those at $25^{\circ}C$, respectively. These results will be utilized on constructing model-based state observer or an on-line identification and an adaptation of the model parameters in battery management systems for hybrid electric vehicle applications.

상황에 따른 개념 유형의 국면 분석을 통한 중학교 과학 영재아들의 조석에 관한 정신모형 탐색 (Investigation of Mental Models about Tide for Scientifically Talented Middle School Students by Analyzing Facet of Conceptual Types by Context)

  • 이기영
    • 한국지구과학회:학술대회논문집
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    • 한국지구과학회 2005년도 추계학술발표회 논문집
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    • pp.254-262
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    • 2005
  • 본 연구에서는 중학교 과학 영재아들이 가지고 있는 조석에 관한 정신모형을 탐색하기 위하여 상황에 따른 개념 유형을 분류하고, 각 유형들을 구성하는 국면들을 분석하였다. 조석 현상에 관해 두 가지 상황으로 구성된 과제 수행을 실시한 후 그 응답 결과를 분석한 결과, 상당수의 학생들이 상황에 따라 서로 다른 개념 유형을 나타내었다. 상황에 따른 개념 유형들을 구성하고 있는 국면을 분석한 결과, 각 유형들은 내용-일반적 국면을 공통적으로 포함하고 있었으나, 내용-특정적 국면과 전략적 국면에서는 많은 차이를 나타내었다. 두 가지 상황에서 나타나는 개념 유형들과 이들 유형을 구성하는 국면들을 조합하여 학생들의 정신모형을 분석한 결과 다음과 같은 4가지 모형으로 나눌 수 있었다: (1) Tide model (2) Force model (3) Phase model (4) Hybrid model. Tide model은 과학적으로 옳은 모형이며, Force model과 Phase model은 옳지 않은 모형이며, Hybrid model은 혼합 모형으로 상황에 따라 나타나는 개념 유형이 서로 부합되지 않는 모형이다. 중학교 과학 영재아들이 조석 현상에 대해 가장 많이 가지고 있는 모형은 Tide model(45.0%)이었으며, 그 다음으로는 Hybrid model(30.0%), Force model(12.5%), Phase model(7.5%) 순으로 나타났다.

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A Proposal for Diesel Spray Model Using a TAB Breakup Model and Discrete Vortex Method

  • Yeom, Jeong-Kuk;Lee, Myung-Jun;Chung, Sung-Sik;Ha, Jong-Yul;Jiro Senda;Hajime Fujimoto
    • Journal of Mechanical Science and Technology
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    • 제16권4호
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    • pp.532-548
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    • 2002
  • A hybrid model consisting of a modified TAB (Taylor Analogy Breakup) model and DVM (Discrete Vortex Method) is proposed for numerical analysis of the evaporating spray phenomena in diesel engines. The simulation process of the hybrid model is divided into three steps. First, the droplet breakup of injected fuel is analyzed by using the modified TAB model. Second, spray evaporation is calculated based on the theory of Siebers'liquid length. The liquid length analysis of injected fuel is used to integrate the modified TAB model and DVM. Lastly, both ambient gas flow and inner vortex flow of injected fuel are analyzed by using DVM. An experiment with an evaporative free spray at the early stage of its injection was conducted under in-cylinder like conditions to examine an accuracy of the present hybrid model. The calculated results of the gas jet flow by DVM agree well with the experimental results. The calculated and experimental results all confirm that the ambient gas flow dominates the downstream diesel spray flow.

Evaluation of ductility capacity of steel-timber hybrid buildings for seismic design in Taiwan

  • Chen, Pei-Ching;Su, I-Ping
    • Earthquakes and Structures
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    • 제23권2호
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    • pp.197-206
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    • 2022
  • Recently, steel-timber hybrid buildings have become prevalent worldwide because several advantages of both steel and timber structures are maintained in the hybrid system. In Taiwan, seismic design specification related to steel-timber hybrid buildings remains void. In this study, the ductility capacity of steel-timber hybrid buildings in Taiwanese seismic design specification is first proposed and evaluated using nonlinear incremental dynamic analysis (IDA). Three non-linear structural models, 12-story, 8-story, and 6-story steel-timer hybrid buildings were constructed using OpenSees. In each model, Douglas-fir was adopted to assemble the upper 4 stories as a timber structure while a conventional steel moment-resisting frame was designated in the lower part of the model. FEMA P-695 methodology was employed to perform IDAs considering 44 earthquakes to assess if the ductility capacity of steel-timber hybrid building is appropriate. The analytical results indicate that the current ductility capacity of steel moment-resisting frames can be directly applied to steel-timber hybrid buildings if the drift ratio of each story under the seismic design force for buildings in Taiwan is less than 0.3%. As a result, engineers are able to design a steel-timber hybrid building straightforwardly by following current design specification. Otherwise, the ductility capacity of steel-timber hybrid buildings must be modified which depends on further studies in the future.

하이브리드 정보서비스 모델의 설계원칙 (Principles of Design for Hybrid Information Service Model)

  • 노진구
    • 정보관리학회지
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    • 제18권3호
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    • pp.87-114
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    • 2001
  • 하이브리드 정보환경은 적절한 범위의 이질적인 정보서비스가 단일 인터페이스를 통하여 지속적이며 통합된 방법으로 이용자에게 제공되는 환경이라고 할 수 있다. 하이브리드 정보환경은 지역 및/혹은 원격 분산서비스 인쇄 및 전자적 서비스를 포함할 수 있다. 그 환경은 객체들이 소속되어 있는 영역에 상관없이 발견, 소재. 신청, 배달 및 이용 등과 같은 기능들의 일부 혹은 전부를 제공할 것이다. 본 연구는 전통적 정보서비스와 전자적 정보서비스를 통합하고 다양한 유형의 정보자원에 대한 연속적이며 통합된 접근을 요하는 하이브리드 정보환경과 하이브리드 도서관에 대한 이해를 통하여 차이브리드 정보서비스의 필요성을 제기하였다. 이어서, 하이브리드 정보서비스 모델 설계에 필요한 기본개념과 이를 바탕으로 한 Agora. BUILDER, HeadLine. HyLife, MALIBU 같은 주요 하이브리드 도서관 프로젝트에 대해 살펴보았다. 아울러 일반적인 하이브리드 정보서비스 모델을 고찰하고 하이 브리드 정보서비스 모델 구축을 위한 기본원칙으로 통합(integration), 연속성(seamlessness), 인증(authentication), 상호연결성(interconnectivity), 정보탐색과정 환경의 개인화(personalisation) 등의 5가지 기본 원칙을 제시하였다.

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화염편 모델을 이용한 하이브리드 로켓의 연소과정 해석 (Flamelet Modeling for Combustion Processes of Hybrid Rocket Engine)

  • 임재범;김용모;윤명원
    • 유체기계공업학회:학술대회논문집
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    • 유체기계공업학회 2006년 제4회 한국유체공학학술대회 논문집
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    • pp.245-248
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    • 2006
  • Hybrid propulsion systems provide many advantages in terms of stable operation and safety. However, classical hybrid rocket motors have lower fuel regression rate and combustion efficiency compared to solid propellant rocket motor. Accordingly, the recent research efforts are focused on the improvement of engine efficiency and regression rate in the hybrid rocket engine. The present study has numerically investigated the combustion processes in the hybrid rocket engine. The turbulent combustion is represented by the flamelet model and Low Reynolds number $k-{\varepsilon}$ turbulent model is employed to reduce the uncertainties for convective heat transfer near solid fuel surface having strong blowing effect. Based on numerical results, the detailed discussions have been made for the effects of oxygen injection methods and oxygen injection flow rate on flame structure and regression rate in the vortex hybrid rocket engines

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