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다중완화시간 격자 볼츠만기법을 이용한 다양한 종횡비의 리드드리븐 공동유동 수치해석연구
황팅팅(Tingting Huang),송주헌(Juhun Song),임희창(Hee-Chang Lim) 한국가시화정보학회 2020 한국가시화정보학회지 Vol.18 No.3
This study performs a numerical simulation of lid driven rectangular cavity flow with different aspect ratios of k = 0.5 to 4 under Reynolds 100, 1,000, 10,000 by using multi-relaxation time (MRT) Lattice Boltzmann Method (LBM). In order to achieve better convergence, well-posed boundary conditions in the domain should be defined such as no-slip condition on side and bottom solid wall surfaces and uniform horizontal velocity on the top of the cavity. This study focuses on the flow inside different shape of rectangular cavity with the aim to observe the effect of the Reynolds number and aspect ratio on the flow characteristics and primary/secondary vortex formation. In order to validate the study, the results have been compared with existing works. The result shows that the Reynolds number and the aspect ratio both has substantial effects on the flow inside the lid-driven rectangular cavity.
이병화(Byounghwa Lee),송주헌(Juhun Song),이천성(Cheonsung Lee),장영준(Youngjune Chang),전충환(Chunghwan Jeon) 대한기계학회 2009 대한기계학회 춘추학술대회 Vol.2009 No.5
This study is to investigate the effect of the moisture, volatile matter and size in the coal on the pulverized coal combustion characteristics by means of a three-dimensional numerical simulation method. The results show that combustion temperature in the boiler utilizing sub-bituminous coal is entirely getting lower as the moisture content increases. When sub-bituminous coal is utilized in order to get equivalent output power in the boiler which was designed for bituminous coal, it should be considered not only heating value but cooling effect driven from increasing air and coal. The more volatile matter content in a coal is, the more combustion occurs quickly and rapidly near burner. Therefore, as the temperature near region of burner becomes high, the burner is expected to be damaged. Also, mean temperature at the elevation burner located is higher than those of other elevation, because of characteristics of volatile matter. On the other hand, temperature in the part of super-heater where is rear region of boiler is lower, for the combustion time of particle is very short. However, as the particle size increases, the temperature rear region of boiler show tendency to return back to conditions where temperature is similar to bituminous coal condition, for combustion burning time of coal can be keep longer. This implies that in order to apply sub-bituminous coal into the boiler designed for bituminous coal, enlarging pulverized coal particle size could be an alternative to maintain appropriate temperature in the rear region of the boiler.
DPF 위치에 따른 엔진과 터보차저 성능 변화에 관한 영향의 수치 해석적 연구
김강욱(Kangwook Kim),송주헌(Juhun Song) 한국자동차공학회 2013 한국자동차공학회 지부 학술대회 논문집 Vol.2013 No.4
The objective of the study was to analyze the impact of DPF(Diesel Particulate Filter) place on the engine and turbocharger performance with GT-Power. The location of the after-treatment system within the exhaust system of a turbocharged diesel engine can have significant impact on the turbocharger and engine performance. The study is conducted in DPF of after-treatment system upstream of the turbocharger as opposed to the more conventional downstream location. This study has shown that turbocharger efficiency and BMEP(Brake Mean Effective Pressure) advantage exist for a pre-turbine configured DPF as compared to the post-turbine counterpart. Under the post-turbine configuration, When the speed of engine is low-speed, the performance is more efficient than the pre-turbine configuration. As the speed of engine increases, the results indicate that a pre-turbo configuration is more desirable than a post-turbine configuration in terms of BSFC(Brake Specific Fuel Consumption).
미분탄 연소로에서 연소특성에 미치는 석탄특성에 관한 연구
이병화(Byounghwa Lee),송주헌(Juhun Song),이천성(Cheonsung Lee),장영준(Youngjune Chang),전충환(Chunghwan Jeon) 대한기계학회 2009 大韓機械學會論文集B Vol.33 No.10
This study is to investigate the effect of the moisture, volatile matter and particle size in the coal on the pulverized coal combustion characteristics using CFD. The results show that as the moisture content in coal increases, flame temperature decreases because of heat loss driven from latent heat of vaporization and reduction of heating value. As the volatile matter content in the coal increases, the temperature in the region near the burner increases, while the temperature in rear region of boiler decreases. The solution to keep the temperature in the rear region of boiler is suggested that particle size is needed to be larger. As the particle size increases, the temperature in the rear region of boiler show tendency to increase, for combustion burning time of coal could be extended.
입자온도의 직접적인 측정법을 이용한 석탄촤 고압 CO2 가스화 반응률에 관한 연구
이동방(Dongfang Li),김량균(Ryanggyoon Kim),송주헌(Juhun Song),전충환(Chunghwan Jeon) 대한기계학회 2011 대한기계학회 춘추학술대회 Vol.2011 No.10
Gasification kinetics of coal char of coal Wira with CO2 at elevated pressure was investigated with a Pressurized Wire Heating Reactor(PWHR). An experimental method with the capacity to heat the coal char particle and measure its temperature directly (as with a thermocouple) was developed. The effects of gasification temperature(1100 ?. 1400oC), partial pressure of carbon dioxide(0.2 ?. 0.8), and total pressure(10 ?. 30atm) on gasification rate of the coal char with CO2 were determined. The modified nth-order reaction models were then employed to analyze the reaction kinetics.
정적연소실내 예연소실 설계인자 및 스월 강도에 따른 연소특성에 관한 실험적 연구
전충환(Chunghwan Jeon),양인규(Ingyu Yang),김현규(Hyunkyu Kim),송주헌(Juhun Song),장영준(Youngjune Chang),조승완(Seungwan Cho) 한국자동차공학회 2010 한국자동차공학회 부문종합 학술대회 Vol.2010 No.5
Natural gas is a promising alternative fuel to meet strict engine emission regulations in many countries. The development of natural gas engines requires low emissions along with the demand for better fuel consumption and increased power ratings. In this study, a cylindrical Constant Volume Combustion Chamber(CVCC) was used to investigate the combustion characteristics under different swirl intensity and equivalence ratio. The maximum combustion pressure and mass fraction of burned gas was evaluated in particular by the orifice diameter, volume ratio of pre-chamber, equivalence ratio and swirl intensity. This result could provide combustion characteristics with variation of swirl intensity.
정적연소기에서 디젤 분무 증발과 연소특성에 관한 실험 및 수치적 연구
최낙원(Nakwon Choi),정정훈(Jeonghoon Jeong),전충환(Chunghwan Jeon),장영준(Youngjune Chang),송주헌(Juhun Song) 한국자동차공학회 2011 한국자동차공학회 부문종합 학술대회 Vol.2011 No.5
In this study, experimental and numerical investigation for diesel spray evaporation and combustion was carried out in a constant volume combustion chamber(CVCC) on various ambient gas pressure and temperature. In the experiment, the spray was injected into CVCC by common rail system and then images of the spray were acquired by high speed camera and the calculation study was implemented under same condition with experiment by using AVL-Fire. There was a good agreement between experimental and computational results such as spray penetration, ignition delay.
분위기 압력에 따른 커먼레일 시스템의 비증발 디젤 분무특성에 관한 실험적 연구
전충환(Chunghwan Jeon),정정훈(Jeonghoon Jeong),김현규(Hyunkyu Kim),송주헌(Juhun Song),장영준(Youngjune Jang),조승완(Seungwan Cho) 한국자동차공학회 2010 한국자동차공학회 부문종합 학술대회 Vol.2010 No.5
It is very important to understand the spray characteristics and fuel injection conditions in direct injection diesel engine because the emission gas compositions from diesel engines are related to spray formation processes. The objective of the papers is the characteristics of the macroscopic behaviour of diesel sprays. In this study, the characteristics of diesel spray has been studied using a shadowgraph and laser scattering. The spray characteristics such as spray tip penetration and spray cone angle studied at various injection pressure and ambient pressure.
정적연소기에서 디젤 연소특성에 관한 실험 및 수치적 연구
최낙원(Nakwon Choi),정정훈(Jeonghoon Jeong),전충환(Chunghwan Jeon),송주헌(Juhun Song) 한국자동차공학회 2011 한국자동차공학회 지부 학술대회 논문집 Vol.2011 No.4
In this study, experimental and numerical investigation for diesel combustion was carried out in a constant volume combustion chamber(CVCC) on various ambient gas pressure and temperature. In the experiment, the spray was injected into CVCC by common rail system and then images of the spray were acquired by high speed camera and the calculation study was implemented under same condition with experiment by using AVL-Fire. There was a good agreement between experimental and computational results such as combustion, ignition delay.
유다연(Dayeon Yu),이천성(Cheonseong Lee),김성곤(Songgon Kim),이병화(Byounghwa Lee),송주헌(Juhun Song),장영준(Youngjune Chang),이시훈(Sihyun Lee),전충환(Chunghwan Jeon) 대한기계학회 2010 대한기계학회 춘추학술대회 Vol.2010 No.11
In order to investigate devolatilization characteristics for ashless coal with relatively low ash content and high heating value, an experiment was performed in different bed configurations of TGA and DTF(Drop Tube Furnace) at atmospheric pressure condition. The heating rate was 10℃/min up to 950℃ in TGA, while temperatures varied from 500 to 1300℃ in DTF. A weight loss and particle temperature were obtained to be used for kinetic analysis of the devolatilization. The kinetic parameters including an activation energy and pre-exponential factor for ashless coal were obtained using Coats-Redfern method in TGA and single step method in DTF. Furthermore, the devolatilization kinetics of the ashless coal were compared with the results of different kinds of conventional coal such as sub-bituminous and bituminous.