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성효성(Hyo-Seong Seong),장낙원(Nakwon Jang),박정도(Jeong-Do Park),이성환(Sung-Hwan Lee),도근영(Geun-Young Doe),이정재(Jurng-jae Yee) 한국항해항만학회 2009 한국항해항만학회 학술대회논문집 Vol.2009 No.공동학술
분산발전원의 위치 변경에 따른 전력조류 및 송전전력 손실 평가를 통하여 도시차원에 적합한 발전원 설치점 선정 기법의 개발이 시급하다. 본 연구에서는 전력손실을 고려하여, 분산전원이 주변의 모선 및 선로에 미치는 영향을 최소화 할 수 있도록, 분산전원의 설치지점을 선정하는 방안을 제안한다. In this paper we developed positioning algorithm considering distributed energy resource of ocean side by load flow calculation using Newton-Rhapson method.
디젤 엔진 분무의 액적 미립화 모델 및 벽면 충돌 모델에 관한 연구
김홍석,성낙원,Kim, Hongsuk,Sung, Nakwon 대한기계학회 1999 大韓機械學會論文集B Vol.23 No.1
In this research computational methods for the droplet atomization and spray wall impingement are studied for the non-evaporating diesel fuel spray. The TAB(Taylor Analogy Breakup) model and Wave model are compared with experiments in order to describe droplet atomization process. The Watkins model and O'Rourke model are compared to simulate the spray wall impingement. As a result, It is found that the application of the Wave model has a good agreement with the experimental data in the case of high pressure injection. With regard to wall Impingement phenomena, it is found that the Watkins model is appropriate to the high temperature cylinder wall condition, while the O'Rourke model is appropriate to cold starting problem.
주변 압력이 연료 분무의 증발 및 착화에 미치는 영향에 관한 연구
김홍석(Hongsuk Kim),성낙원(Nakwon Sung) 한국자동차공학회 2002 한국자동차공학회 춘 추계 학술대회 논문집 Vol.2002 No.5_1
The effect of ambient pressure on evaporation of an n-heptane fuel droplet and a spray was investigated, and its effect on ignition was also studied. The calculations were performed using modified KlVA-3V code, in which the atomization model based on the stability theory of a liquid jet, the droplet evaporation model considered the real gas effect in phase equilibrium and Shell ignition model were implemented into KlVA-3V cede. From this study following results were obtained: Droplet lifetime decreased with pressure when the ambient temperature was low, but it increased with pressure when the ambient temperature high. Spray evaporation was enhanced with ambient pressure due to the effect of enhanced atomization and single droplet evaporation at high temperature. Additionally, the reduction of ignition delay time with ambient pressure was explained by the enhanced spray evaporation.
분할 분사가 디젤 엔진의 수트 및 질소 산화물에 미치는 영향
김진훈(Jinhoon Kim),성낙원(Nakwon Sung) 한국자동차공학회 2002 한국자동차공학회 Symposium Vol.2002 No.11
The modified KIVA-3V code was used to study the soot and NO emissions of a diesel engine with split injection. A model of soot suggested by Foster er al.[1] was implemented in KIVA-3V code. In order to understand the emission characteristic of split injection, the first injection quantity and injection dwell were varied. Regarding soot, there existed the optimal conditions of split injection for lowest soot reduction by varying the first injection quantity and injection dwell. The optimal conditions were found when the first injection quantity was large enough to burn actively. The results showed that NO emissions increased as the percentage of fuel in the first injection was increased and the injection dwell was decreased. Increaed NO emission was due to higher combustion temperature.
화염면적밀도 모델을 이용한 선회유동이 있는 정적연소기의 난류 예혼합 LPG 연소 특성 예측
김홍석(Hongsuk Kim),성낙원(Nakwon Sung) 한국자동차공학회 2002 한국자동차공학회 Symposium Vol.2002 No.11
Numerical analysis for the turbulent premixed reacting swirl flow in a constant volume vessel was performed with the flame surface density(FSD) model. To describe the effect of flame quenching near the wall, the region of the reacting flow was divided into three zones with distance from the wall, turbulent, buffer, and viscous zones, The production rates for FSD in the buffer zone was restricted using an arbitrarily chosen critical strain rate and arrhenius type laminar reaction rate was applide for the viscous zone. The results from the FSD model were compared with the existing experimental results. The combustion characteristics of different equivalence ratios, turbulent intensity and swirl flow velocities were also studied using the FSD model.
LPG 엔진 연소실 내 유동 및 LPG 분무 특성에 관한 연구
이정민(Jeongmin Lee),성낙원(Nakwon Sung) 한국자동차공학회 2002 한국자동차공학회 Symposium Vol.2002 No.11
To investigate the characteristics of LPG spray and flow field generated through the intake and compression periods, a numerical research was carried out using multidimensional flow and spray simulation code, KIVA3V. LPG spray evaporation quantities were increased with low ambient pressure and high ambient temperature. Evaporation quantities were clearly increased about 9% as pressure was decreased from 2.0bar to 1.0bar. On the other hand, they were a little increased as temperature was varied from 293k to 313k, Another investigation on the effect of an engine speed on incylinder flow generated by a helical port showed turbulent intensity was incresed with an increased engine speed.