• 오토저널
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• 제10권6호
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• pp.25-38
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• 1988

As a mean of increasing engine power, great attention has been concentrated on the turbo-charging owing to better fuel economy, smaller engine size and lower emission. The performance in turbocharged engine depends not only on the efficiency of the engine and the turbocharger used, but also on the total characteristics of the system by the matching turbocharger to the engine. The matching of the turbocharger to the engine has been usually accomplished by the empirical techniques with a great deal of laborious work. It would be better to predict the performance and emission in the turbocharged engine using the effective simulation model. In this study, computer simulation program has been developed to predict the transient variation of properties of gas in the cylinder, intake and exhaust pipes, the engine performances and emissions.

• 대한기계학회논문집B
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• 제34권6호
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• pp.615-622
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• 2010

본 연구에서는 중형 직분식 선박용 엔진의 성능 및 NOx 배출물 예측을 위한 0-D multi-zone 분무 연소 모델이 개발되었다. 모델은 상용 1-D 사이클 해석 프로그램 (Boost)와 연동할 수 있도록 개발되었으며, 흡배기 시스템을 포함한 엔진 전체에 대한 동시 해석이 가능하였다. 연소 모델은 Fortran90 으로 개발되었으며, AVL 에서 제공된 'user defined high pressure cycle (UDHPC) interface'를 통해 Boost 와 연동되었다. 두 가지의 인젝터(8 홀, 10 홀)에 대해 두 가지 부하에서 해석을 수행하였으며, 해석 결과는 실제 엔진의 성능 실험 결과를 잘 추종하였다.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2004년도 제22회 춘계학술대회논문집
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• pp.513-520
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• 2004

A steady-state/transient performance simulation model was newly developed for the propulsion system of the CRW (Canard Rotor Wing) type UAV (Unmanned Aerial Vehicle) during flight mode transition. The CRW type UAV has a new concept RPV (Remotely Piloted Vehicle) which can fly at two flight modes such as the take-off/landing and low speed forward flight mode using the rotary wing driven by engine bypass exhaust gas and the high speed forward flight mode using the stopped wing and main engine thrust. The propulsion system of the CRW type UAV consists of the main engine system and the duct system. The flight vehicle may generally select a proper type and specific engine with acceptable thrust level to meet the flight mission in the propulsion system design phase. In this study, a turbojet engine with one spool was selected by decision of the vehicle system designer, and the duct system is composed of main duct, rotor duct, master valve, rotor tip-jet nozzles, and variable area main nozzle. In order to establish the safe flight mode transition region of the propulsion system, steady-state and transient performance simulation should be needed. Using this simulation model, the optimal fuel flow schedules were obtained to keep the proper surge margin and the turbine inlet temperature limitation through steady-state and transient performance estimation. Furthermore, these analysis results will be used to the control optimization of the propulsion system, later. In the transient performance model, ICV (Inter-Component Volume) model was used. The performance analysis using the developed models was performed at various flight conditions and fuel flow schedules, and these results could set the safe flight mode transition region to satisfy the turbine inlet temperature overshoot limitation as well as the compressor surge margin. Because the engine performance simulation results without the duct system were well agreed with the engine manufacturer's data and the analysis results using a commercial program, it was confirmed that the validity of the proposed performance model was verified. However, the propulsion system performance model including the duct system will be compared with experimental measuring data, later.

• 정보처리학회논문지A
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• 제10A권2호
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• pp.111-122
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• 2003

군사용 워게임 시뮬레이션 모델들의 상호연동을 위해서는 국제표준연동(HLA : High Level Architecture)구조를 반드시 갖추어야하며 타 모델과 연동시 발생되는 시스템 오버헤드를 줄이기 위해서는 병렬 시뮬레이션 엔진 도입이 효과적이다. 그러나 기존 군사용 워게임 시뮬레이션 모델엔진의 이벤트 처리는 순차적 이벤트-드리븐 방식으로 처리하고 있다. 이는 병렬로 처리 시 글로벌 자료영역에 대한 동시참조등의 문제점들이 발생하기 때문이다. 아울러 기존 시뮬레이션 플랫폼으로 다중 CPU 시스템을 사용하여도 여러 개의 CPU를 다 활용하지 못하는 결과를 초래하고 있다. 따라서 이 논문에서는 군사용 워 게임 모델의 시스템 처리능력 향상과 글로벌 자료 영역에 대한 동시참조, 대외적인 시뮬레이션 시간처리, 장애 회복(Crash Recovery)시 병행 처리된 이벤트들의 순서를 보장 할 수 있는 객체모델에 기반한 병렬 시뮬레이션 엔진으로의 전환을 제안한다 이 전환된 병렬 시뮬레이션 엔진은 다중 CPU 시스템(SMP)상에서도 병렬 실행이 가능하도록 설계하고 구현하였다.

• Journal of Advanced Marine Engineering and Technology
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• 제25권6호
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• pp.1260-1271
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• 2001

The simulation program which predicts the gas behavior in a spark ignition engine has been developed and verified by the comparison with the experimental results foy the MPI engine, naturally aspirated and turbochared engines with a carburettor. First paper describes the calculations of the behavior of gas in the intake and exhaust system. The generalized method of characteristics including friction, heat transfer, area change and entropy gradients was used to analyse the pipe flow The constant-Pressure model was applied for the analysis of the flow through engine valved, and the constant-pressure perfect-mixing model was applied for the flow at manifold junction. The concept of the sudden area change was used for the muffler and catalytic convertor. Fer the plenum chamber in an MPI engine, constant-pressure model and constant-volume model were both examined. Through the comparison of predicted results with experiments, the simulation program was verified by showing good prediction of the behavior of IC engine qualitatively and quantitatively under wide range of operating conditions.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2010년도 제35회 추계학술대회논문집
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• pp.733-736
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• 2010

한국항공우주연구원은 한국형발사체 2단용 액체로켓엔진의 개발 및 인증을 위한 엔진고공환경모사 연소시험설비의 예비설계를 수행하였다. 고흥 우주센터에 구축될 예정인 엔진 고공연소시험설비는 액체산소와 케로신을 공급하여 한국형발사체 2단 엔진의 고공환경모사 시험을 지상에서 수행할 수 있도록 구성된다. 고공환경 모사는 액체로켓엔진의 후류제트로 작동되는 초음속 디퓨저로 구현된다.

• 대한기계학회논문집
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• 제13권3호
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• pp.500-507
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• 1989

본 논문에서는 흡배기 변동압을 실측하여 이것을 계산의 입력수치로 사용 하는 전산프로그램을 개발하여 간단하면서도 정확한 사이클 시뮬레이션이 가능하도록 하여 체적효율을 예측하였다.

• International Journal of Automotive Technology
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• 제6권2호
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• pp.133-139
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• 2005

In this study, a three-dimensional transient simulation with a knock model was performed to predict knock occurrence and autoignition site in a heavy-duty LPG engine. A FAE (Flame Area Evolutoin) premixed combustion model was applied to simulate flame propagation. The coefficient of the reduced kinetic model was adjusted to LPG fuel and used to simulate autoignition in the unburned gas region. Engine experiments using a single-cylinder research engine were performed to calibrate the reduced kinetic model and to verify the results of the modeling. A pressure transducer and a head-gasket type ion-probe circuit board were installed in order to detect knock occurrences, flame arrival angles, and autoignition sites. Knock occurrence and position were compared for different piston bowl shapes. The simulation concurred with engine experimental data regarding the cylinder pressure, flame arrival angle, knock occurrence, and autoignition site. Furthermore, it provided much information about in-cylinder phenomena and solutions that might help reducing the knocking tendency. The knock simulation model presented in this paper can be used for a development tool of engine design.

• 에너지공학
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• 제24권3호
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• pp.55-60
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• 2015

Recent engine development has focused mainly on the improvement of engine efficiency and output emissions. The improvements in efficiency are being made by friction reduction, combustion improvement and thermodynamic cycle modification. Computer simulation has been developed to predict the performance of a spark ignition engine. The effects of various cylinder pressure, heat release, flame temperature, unburned gas temperature, flame properties, laminar burning velocity, turbulence burning velocity, etc. were simulated. The simulation and analysis show several meaningful results. The objective of the present study is to develop a combustion model for a spark ignition engine running with isooctane as a fuel and predicting its behavior.

• 오토저널
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• 제11권3호
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• pp.60-71
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• 1989

In this paper the structure of an engine and its interaction are investigated by a mathematical model for the performance evaluation. The total system is composed of air-fuel inlet element, intake manifold, combustion, engine dynamics and emission. Their control functions are schematically evaluated. Because of the model constructure with general engine functions and computer simulation of the chosen engine, physical characteristics of the corresponding engine and the engine data of normal operation states are used. According to the study, it is possible to predict the mixture rate by the difference in the mass of fuel and air flowing into cylinder and to evaluate and trace dynamic characteristic of operation state under various operating conditions. The model characteristic under the transient operating condition to evaluate operating of actual engine through the result of simulation.