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최정열(Jeong-Yeol Choi),김진수(Chin-Su Kim),오세종(Se-Jong Oh) 한국전산유체공학회 2000 한국전산유체공학회 학술대회논문집 Vol.2000 No.5
For the analysis of compressible flow with real gas effect, characteristic form of Roe's Riemann solver was derived again using real gas equation of state and variable specific heat, and it was extended to multi component reactive system. From this study, it is known that some correction should be made for the use of existing numerical algorithm. 1) Sonic speed and characteristic variable should be corrected with real gas effect. 2) Roe's average was applicable only with the assumption of constant properties. 3) Artificial damping term and characteristic variables should be corrected but their influence may not be significant.
김진수(Chin-Su Kim),오세종(Jeong-Yeol Choi),최정열(Se-Jong Oh) 한국전산유체공학회 2000 한국전산유체공학회 학술대회논문집 Vol.2000 No.10
This paper presents the results of the application of a computational fluid dynamics algorithm for the simulation of plasma flows of arc-heated jet. The underlying physical model is based on the axisymmetric form of the conservation equations that are coupled with an arc model including Ohm heating, electromagnetic forces. The arc model given as a source term in fluid dynamic equations is determined by a solution of electric potential field governed by an elliptic partial differential equation. The governing equation of electric field is loosely coupled with fluid dynamic equations by an electric conductivity that is a function of state variables. However, the electric fields and flow fields cannot be solved in fully coupled manner, but should be solved iteratively due to the different characteristics of governing equations. With this solution approach, several applications of arc flow analysis will be presented including Arc Thruster and Circuit Breaker.
신재렬(Jae-Ryul Shin),이대성(Dae-Sung Lee),오세종(Se-Jong Oh),최정열(J.-Y. Choi) 한국항공우주학회 2008 韓國航空宇宙學會誌 Vol.36 No.9
하이드라진(N₂H₄) 아크젯 추력기의 열화학 유동장 해석을 위한 전산유체해석을 수행하였다. 열복사와 전기장이 고려된 압축성 유동해석을 위해서 RANS 방정식을 수정하여 사용하였다. 로렌츠 힘과 Ohm 가열효과를 고려한 Maxwell 방정식이 유동방정식과 결합되어 전기 방전으로 인한 전기장해석을 위해 이용되었다. 아크젯 추력기 내부에서 유동장은 충분히 고온상태이기에 화학평형 해석이 이용되었으며, 광학 두께를 이용한 열복사 모델이 유동방정식에 적용되었다. 계산 결과들은 아크젯 추력기유동이 동결유동에 비해 추력은 180%증가되며, 비추력은 200%가까이 상승됨을 보여준다. 또한 유동장 해석 결과들은 아크젯 추력기 내부의 열적 물리적 특성에 대한 이해를 돕는다. The computational fluid dynamic analysis has been conducted for the thermo-chemical flow field in an arcjet thruster with mono-propellant Hydrazine (N₂H₄) as a working fluid. The Reynolds Averaged Navier-Stokes (RANS) equations are modified to analyze compressible flows with the thermal radiation and electric field. the Maxwell equation, which is loosely coupled with the fluid dynamic equations through the Ohm heating and Lorentz forces, is adopted to analyze the electric field induced by the electric arc. The chemical reactions of Hydrazine were assumed to be infinitely fast due to the high temperature field inside the arcjet thruster. The chemical and the thermal radiation models for the nitrogen-hydrogen mixture and optical thick media respectively, were incorporated with the fluid dynamic equations. The results show that performance indices of the arcjet thruster with 1㎾ arc heating are improved by amount of 180% in thrust and 200% in specific impulse more than frozen flow. In addition thermo-physical process inside the arcjet thruster is understood from the flow field results.
김혜성(Hye-Sung Kim),양원석(Won-Seok Yang),김귀순(Kui-Soon Kim),오세종(Se-Jong Oh),최정열(Jeong-Yeol Choi) 한국추진공학회 2014 한국추진공학회 학술대회논문집 Vol.2014 No.12
세계 각국에서는 군사 또는 과학의 목적으로 다양한 극초음속 비행체 연구 개발 프로그램이 진행되고 있으며, 관련 기술 확보를 위해 소형 발사체나 미사일을 부스터로 사용하는 비행시험 프로그램이 대두되고 있다. 호주는 HyShot 비행시험 프로그램의 뒤를 이어 미국과 협력하여 HIFiRE 프로그램을 수행하고 있으며, 국내에서도 스크램제트 기반 추진기관에 관한 다양한 연구가 이루어지고 있다. 이에 따라 본 논문에서는 향후 수행될 RBCC 추진기관 비행시험에 필요한 과학로켓 임무 분석을 수행하였으며, 그 결과 현재 국내에서 사용되고 있는 발사체 중 KSR-Ⅱ가 가장 적합할 것으로 예측하였다. Various R & D programs of hypersonic flight vehicle are progressed with the purpose of military or science worldwide and hypersonic flight test programs using missile or small launch vehicle are on the rise to acquire technologies. Australia is conducting HIFiRE program with USA after HyShot flight test program, and domestic studies of propulsion system based in scramjet are progressed. Accordingly, this paper designs and analyzes a mission of sounding rocket for flight test with RBCC propulsion system to be performed in the future, and shows that KSR-Ⅱ is a best launch vehicle fitted for the mission among domestic launch vehicles now in use.
Kriging 모델기반 유전자 알고리즘을 이용한 RBCC 엔진 유로 최적설계 및 분석
채상현(Sang-Hyun Chae),김혜성(Hye-Sung Kim),이관중(Kwan-Jung Yee),오세종(Se-Jong Oh),최정열(Jeong-Yeol Choi) 한국추진공학회 2017 한국추진공학회지 Vol.21 No.1
A design optimization method is applied for the flow path design of RBCC engine, an important factor for the determining the propulsion performance operating at air-breathing mode. A design optimization was carried out to maximize the specific impulse of the RBCC engine by using a genetic algorithm based on the Kriging model. Results are analyzed using ANOVA and SOM. Design conditions of ramjet and scramjet mode are selected as Mach number 4 at 20 km altitude and Mach number 7 at 30 km, respectively. The optimized design presents that the specific impulse is increased by 7% and 10% on each condition than the baseline design.