• 한국자동차공학회논문집
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• 제7권6호
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• pp.82-90
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• 1999

Numerical analysis of the three dimensional flow in a bus engine room is carried out through this study. The radiator and the fan modeling rare carried out to simulate the flow in an engine room, and the results are focused on the flow in the cavity located in front of the radiator. The numerical simulation results are compared with the experiment . To improve the cooling performance in the bus engine room, the flow inside the cavity is inspected in detail. The complex flow features are found in this region , and the suggestion are made to improve the radiators cooling performance.

• International Journal of Contents
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• 제3권4호
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• pp.8-14
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• 2007

This study focuses on modeling mobile 3D game engine and suggesting modified skinned-mesh schema based on JSR-184 in order to improve the performance in terms of memory consumption and time complexity. Most of the 3D games have used OpenGL-ES low-level APls, which may limit portability and fast developing time. Hence, the 3D mobile game engine providing high-level APls which works on GSM (Global System for Mobile Communication) phones on J2ME, is proposed here in order to optimize the performance for Java environment abiding JSR-184 standard. To prove performance enhancement, skinned-mesh schema on JSR-184 engine is modified and tested. The experimental results are shown.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2006년도 제27회 추계학술대회논문집
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• pp.237-240
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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 regressionrate in the hybrid rocket engine. The present study has numerically investigated the combustion processes and the flame structure 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. Numerical results suggest that the present approach is capable of realistically simulating the combustion characteristics of the hybrid rocket engines.

• 항공우주기술
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• 제8권1호
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• pp.82-97
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• 2009

본 연구에서는 가스발생기 사이클 엔진시스템의 제어특성을 검토하고, 제어기를 구성하기 위한 해석의 일환으로 공칭 작동점 부근에서의 선형해석을 위한 Simulink 수학적 모델을 구성하여, 엔진 스로틀링 과정에 대한 해석을 수행하였다. 스로틀 밸브의 특성이 엔진동특성에 미치는 영향을 검토하기 위하여 추력제어밸브와 가스발생기 혼합비 유지를 위한 압력균형기(pressure stabilizer)의 모델, 그리고 제어밸브 구동용 모터의 수학적 모델을 포함시켰다.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2008년 영문 학술대회
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• pp.59-62
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• 2008

This paper presents an approach of complex control method(CCM) real-time simulation and rapid prototyping for aero-engine control system and describes its principle and realization in detail. This approach is mainly based on MATLAB/RTW for rapid prototyping from system modeling to embedded implementation. According to the simulation results between automatic code and manual code for an aeroengine multi-variable control method, it shows that this approach is feasible and effective, and not only decreases development cycle but also improves the reliability and universality. So a series of problems can be resolved during the simulation stage and rapid application to prototype testing.

• 한국CDE학회논문집
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• 제12권3호
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• pp.163-170
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• 2007

A torque converter, connected to a transmission/transaxle input shaft, connects, multiplies and interrupts the flow of engine torque into the transmission. Damper springs are usually equipped in a torque converter to convert stably the torque power supplied from engine. Damper Springs generally have the most flexible design variables among vehicle transmission parts, so that they could be effective design factors to improve the entire vehicle's performance. Damper spring, however, has geometric complexity after it equipped in a torque converter. For that reason, modeling a damper spring requires expert's knowledge to determine many design parameters and satisfy the functional requirements at the same time. In this paper, we introduce an optimum design method applied in detailed-design stage to reduce design process and financial loss caused by adequate design. Many design variables have to be classified and structuralized for Optimization. This also could make designer concentrate on functional requirements of damper spring, not on design possibility. In addition, modeling an assembled spring has technical restriction with primitives of the current major CAD solutions because of complexity of assembled spring shape. Thus, one of modeling solution presented in this paper since detailed and exact modeling is important for CAE or DMU.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2008년도 춘계학술대회논문집
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• pp.432-435
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• 2008

Launch vehicle for injecting the satellite into its orbit is composed with propulsion system, guidance and navigation system, telemetry and so on. Among the others, the propulsion system is the most important part, because that is the key factor of failure of launch vehicle. Especially, the most of failures were occurred in time of engine startup. Therefore, the study of the conditions for stable engine startup is needed at the first step of development. The many researches were accomplished for mathematical modeling, stable startup engine and control of liquid propellant rocket engine. But the cavitation problem that can be occurred at an inlet of pump associated with propellant feeding system wasn't considered in these works. In this paper, propulsion system model was integrated with clustered engines and propellant feeding system for the simulations of engine startup. As the results of simulations, the requirements were deduced for the stable engine startup without the cavitation at an inlet of pump.

• 대한기계학회논문집A
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• 제39권2호
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• pp.203-209
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• 2015

건설기계 산업에서 배기 및 연비 규제를 만족하기 위하여 엔진 시스템이 점차 전자제어화 되고 있으며, 이를 제어하기 위한 EMS(Engine Management System)의 복잡도 또한 증가하고 있다. 본 연구에서는 EMS function 개발 시, 비용 및 개발기간의 단축을 위한 HiLS(Hardware in the Loop Simulation) 시스템을 개발하였다. HiLS 에 내장된 엔진 모델은 크게 Air, Fuel, Torque 및 동력계 모델로 구성되어있고 실시간 엔진 모사를 위하여 Mean value modeling 방법을 적용하였다. 이 연구를 통하여 개발한 HiLS 시스템은 EGR(Exhaust Gas Recirculation) 시스템과 Turbocharger 가 장착된 건설기계용 디젤엔진을 이용하여 정확성을 검증하였고, 테스트 결과 실 엔진 대비 90% 이상의 정확도를 얻었다.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2000년도 제21회 KOSCO SYMPOSIUM 논문집
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• pp.9-16
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• 2000

The flamelet concept has been widely applied to numerically simulate complex phenomena occurred in nonpremixed turbulent flames last two decades, and recently broadened successfully the applicable capabilities to various combustion problems from simple laboratory flames to gas turbine engine, diesel spray combustion and partially premixed flames. The paper is focused on brief review of recently noticeable work related to flamelet modeling, which includes Lagrangian flamelet approach, RIF concept as well as steady flamelet approach. The limitation of steady flamelet assumption, the effect of transient behavior of flamelets, and the effect of spray vaporization on PDF model have been discussed.

• 한국시뮬레이션학회논문지
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• 제8권1호
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• pp.89-99
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• 1999

The major objective of this research is to propose a design architecture for autonomous defense systems for supporting highly intelligent behavior by combining decision, perception, and action components. Systems with such high levels of autonomy are critical for advanced battlefield missions. By integrating a plenty of advanced modeling concepts such as system entity structure, endomorphic modeling, engine-based modeling, and hierarchical encapsulation & abstraction principle, we have proposed four layered design methodology for autonomous defense systems that can support an intelligent behavior under the complicated and unstable warfare. Proposed methodology has been successfully applied to a design of autonomous tank systems capable of supporting the autonomous planning, sensing, control, and diagnosis.