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분사각 및 홀 직경 변화에 따른 박용디젤엔진 분무특성에 관한 수치해석 연구
한동식(Dong-Sik Han),이병화(Byoung-hwa Lee),배명직(Myung-Jik Bae),장영준(Young-June Chang),전충환(Chung-Hwan Jeon),송주헌(Ju-hun Song) 대한기계학회 2008 대한기계학회 춘추학술대회 Vol.2008 No.5
It is very important to understand spray characteristics and fuel injection conditions in direct-injection diesel engine because emission gas compositions from diesel engines are closely related to spray formation processes. In this study, the characteristics of diesel spray has been studied using a computational fluid dynamics code, named STAR-CD. Reitz & Diwarkar model was used for the breakup models while standard k-ε turbulence model was consider for the compressibility effect due to moving process of piston. In this paper, the numerical simulation was performed to study the spray characteristics such as vapor mass fraction, evaporation rate and SMD and their impact on engine performance.
열전달 특성에 따른 전기용해로 내부 온도예측에 관한 수치적 연구
한동식(Dong-Sik Han),전충환(Chung-Hwan Jeon),장영준(Young-June Chang),송주헌(Ju-Hun Song) 대한기계학회 2008 대한기계학회 춘추학술대회 Vol.2008 No.5
The main objective of this study is to analyze the heat transfer characteristics in the electric furnace. Local temperatures are measured at various locations in the furnace using the B-type thermocouples. In this paper, mathematical heat transfer model has been developed predict temperature distribution by considering the thermal radiation and transient conduction effect on heating element, crucible and furnace walls. The numerical simulation was performed using the ANSYS-Workbench software, and its results were compared with experimental data. The computational results show that the temperature distributions agreed well with experimental results. Finally, a difference in temperature behavior of the crucible was investigated as some heat transfer parameters change.
이중원추형 모형연소기에서 압력과 공기비에 따른 NOx 배출특성
남동현(Dong Hyun Nam),남현수(Hyun Su Nam),한동식(Dong Sik Han),김규보(Gyu Bo Kim),조승완(Seungwan Cho),김한석(Han Suk Kim),전충환(Chung Hwan Jeon) 대한기계학회 2012 大韓機械學會論文集B Vol.36 No.3
본 연구에서는 이중원추형 버너가 장착된 고압연소기를 이용하여 입구공기온도, 공기비 그리고 연소실 압력조건에 따른 NOx 배출 특성을 실험적으로 조사하였다. 배기가스 온도와 NOx 배출량은 동일한 연소실 끝단지점에서 측정되었다. NOx 배출량은 공기비가 증가함에 따라 감소하는 경향을 나타내었으며, 입구공기 온도와 연소실의 압력이 높아질수록 증가하는 경향을 나타내었다. 특히 입구공기온도의 증가는 희박 영역에서 가연한계를 증가시켜 높은 단열화염 온도를 가짐에도 불고하고 저감된 NOx 배출 수준을 얻을 수 있었다. 연소실 압력이 증가할수록 Thermal NOx의 영향을 받는 영역에서의 NOx 배출은 큰 폭의 상승을 보였으나, 공기비가 1.8이상인 영역에서는 적은 연료량으로 인하여 적은 상승폭을 나타내었다. This work presents an experimental investigation of NOx emissions according to inlet air temperature (550?660 K), stoichiometric air ratio (λ, 1.4?2.1), and elevated pressure (2?5 bar) in a High Press Combustor (HPC) equipped with a double cone burner, which was designed by Pusan Clean Coal Center (PC3). The exhaust-gas temperature and NOx emissions were measured at the end of the combustion chamber. The NOx emissions generally decreased as a function of increasing λ. On the other hand, NOx emissions were influenced by λ, inlet air temperature and pressure of the combustion chamber. In particular, when the inlet air temperature increased, the flammability limit was extended to leaner conditions. As a result, a higher adiabatic temperature and lower NOx emissions could be achieved under these operation conditions. The NOx emissions that were governed by thermal NOx were greatly increased under elevated pressures, and slightly increased at sufficiently low fuel concentrations (λ>1.8).
정적연소기내 CRSP 설계인자에 따른 연소특성에 관한 실험적 연구
양인규(In-gyu Yang),한동식(Dong-sik Han),김현규(Hyun-kyu Kim),장영준(Young-june Chang),송주헌(Ju-hun Song),전충환(Chung-hwan Jeon) 대한기계학회 2009 대한기계학회 춘추학술대회 Vol.2009 No.11
Natural gas is a promising alternative fuel to meet strict engine emission regulations in many countries. A natural gas engines achieve low emissions but the demand is for better fuel consumption, increased ratings. This study focuses on a cylindrical Constant Volume Combustion Chamber(CVCC) was used to investigate the combustion characteristics under various Combustion Radical Spark Plug(CRSP) design parameters and different equivalence ratio. The maximum combustion pressure and mass fraction burned of combustion was effected by the CRSP orifice diameter, volume ratio and equivalence ratio. This paper shows optimum parameters of CRSP according to combustion characteristics with design parameters.
정적연소기내 예연소실 설계인자가 연소특성에 미치는 영향에 관한 실험적 연구
양인규(In Gyu Yang),한동식(Dong Sik Han),김현규(Hyun Kyu Kim),장영준(Young June Chang),송주헌(Ju Hun Song),전충환(Chung Hwan Jeon) 대한기계학회 2010 大韓機械學會論文集B Vol.34 No.6
천연가스는 최근 세계적으로 강화되고 있는 배기가스 규제를 만족시키기 위한 연료이다. 가스엔진개발에 있어 적은 배기가스와 보다나은 연료 소비효율이 요구되고 있다. 본 연구는 정적연소기 내에서 예연소실 설계 형상인자와 당량비에 따른 연소 특성을 연구하는데 초점을 맞추었다. 특히 예연소실 설계인자 중 오리피스 직경, 체적비와 당량비가 연소 최대압력과 질량연소분율에 미치는 영향에 대하여 연구 하였다. 본 논문은 예연소실 설계인자에 따른 연소 특성을 분석하여, 최적의 예연소실 설계인자를 제공하는 것을 목적으로 하고 있다. Natural gas is a promising alternative fuel that can be used to satisfy the strict engine emission regulations in many countries. To develop natural-gas engines, low emission, efficient fuel consumption, and increased power ratings have to be realized. In this study, a cylindrical constant-volume combustion chamber (CVCC) was used to investigate natural-gas combustion characteristics for different prechamber design parameters and equivalence ratios. In particular, the maximum combustion pressure and mass fraction of the burned gas were evaluated by considering orifice diameter, volume ratio of prechamber and equivalence ratio. Using this result and by analyzing the changes in combustion characteristics with variations in design parameters, the optimum prechamber parameters were determined.