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초음속난류유동장에서 후향계단 후류의 측면제트분사에 대한 수치적연구
김종록(J.R. Kim),김재수(J.S. Kim) 한국전산유체공학회 2002 한국전산유체공학회 학술대회논문집 Vol.2002 No.-
This paper describes numerical research on transverse jet behind rearward-facing step in turbulent supersonic flowfields without chemical reaction. The purpose of transverse jet behind rearward-facing step is to improve mixing of the fuel in the combustor. Two-dimensional unsteady flowfields generated by slot injection into supersonic flow are numerically simulated by integration of Navier-Stokes equation. Final-scale turbulence effects are modeled with two-equation k- E model. Numerical methods are modeled high-order upwind TVDschemes. A total of 4 cases are computed, comprising slot momentum flux ratios at four step heights downstream of the step. These numerical results are represented periodic phenomenon in unsteady flowfields.
역류제트를 이용한 센터바디 디퓨져의 열차폐 특성에 관한 연구
김종록(J.R. Kim),이경환(K.H. Lee),김재수(J.S. Kim) 한국전산유체공학회 2017 한국전산유체공학회지 Vol.22 No.2
In the development of liquid-propellant rocket engines, it is important to simulate high-altitude environments and verify the performance of the engines in these environments. Supersonic diffusers are the most important technology in high-altitude simulation facilities. Using the thermal protection system based on the counter-flow jet, as proposed in this study, the cooling efficiency of the CBD(center-body diffusers) can realize an efficient high-altitude simulation facility for the liquid-propellant rocket engine. The analysis for the supersonic flow with a counter-flow jet was performed by experimental and numerical methods. The thermal protection effect by the counter-flow jet in the center body diffuser was analyzed by a numerical method. When the pressure ratio of counter-flow jet injection is less than 0.5, the cooling effect is insignificant, but when the pressure ratio is 1.0 or more, the cooling effect is more than 1000K.
적응 격자계를 이용한 초음속 난류유동장의 측면제트분사에 대한 수치적연구
김종록(J.R. Kim),김익태(I.T. Kim),김재수(J.S. Kim) 한국전산유체공학회 2001 한국전산유체공학회지 Vol.6 No.2
Two-dimensional steady flowfields generated by slot injection into supersonic flow are numerically simulated by the integration of Navier-stokes equation with two-equation k-turbulence model. High-order upwind scheme is used on unstructured adaptive meshes. The numerical results are compared with experimental data in terms of surface static pressure distributions, the length of the upstream separation region, and the height of the Mach surface for steady flowfields with a Mach number of 3.71 and a unit Reynolds number of 5.83×10^6/m.
김재수,박남은,김종록,김양수,우철훈,박정주,오범석,옥호남 朝鮮大學校 機械技術硏究所 2004 機械技術硏究 Vol.7 No.1
예비설계 단계에서 외형설계,구조설계를 위한 하중분포 계산,발사체의 안정성 및 성능분석을 위하여 데이터베이스형 발사체 공력코드를 개발하였다. 분석방법으로는 동체, 핀의 공력계수와 동체와 핀의 간섭, 핀과 핀사이의 간섭 등의 분석을 거쳐 전체 발사체에 대한 분석이 이루어졌다. 발사체 공력코드의 데이터베이스구성은 기존의 DATCOM의 데이터베이스를 기반으로 발사체 형상에 대한 실험데이터를 추가 구성함으로서 발사체 공력코드의 신뢰성을 증대시켰다. 또한, 기존의 발사체 공력셜계코드와 비교 분석을 수행하여 발사체 공력코드를 검증하였다. For the development of launch vehicle, the aerodynamic characteristics have to be performed for the configuration design in the preliminary design, the load distribution in the detail design, and the performance analysis. The static and dynamic coefficients are analyzed for fins, body and fin-body interface characteristics. A detail analysis is required during the detail design phase, but a rapid analysis is better in the preliminary design. Therefore, the database code, based on the theory and experimental datum, is useful to analyze the variety of models during the preliminary design phase, and the computational aerodynamic code is required to calculate the detail load distribution during the detail design phase. In this computational aerodynamic code, based on the database of theoretical and experimental datum, have been developed.
발사체 공력해석 프로그램 RocketAeroMaster2005 개발
김재수,김종록,우철훈,김태훈,임오택,박정주,오범석,옥호남 朝鮮大學校 機械技術硏究所 2005 機械技術硏究 Vol.8 No.1
예비설계 단계에서 외형설계, 구조설계를 위한 하중분포 계산, 발사체의 안정성 및 성능분석을 위하여 데이터베이스형 발사체 공력코드를 개발하였다. 분석방법으로는 동체, 스트랩온 부스터의 공력계수와 동체와 스트랩온 부스터의 간섭 동의 분석을 거쳐 전체 발사체에 대한 분석이 이루어졌다. 발사체 공력코드의 데이터베이스구성은 기존의 DATCOM의 데이터베이스를 기반으로 발사체 형상에 대한 실험데이터(MD)를 추가 구성함으로서 발사체 공력코드의 신뢰성을 증대시켰다. 또한, 기존의 발사체 공력설계코드와 비교 분석을 수행하여 발사체 공력코드를 검증하였다. For the development of launch vehicle, the aerodynamic characteristics have to be performed for the configuration design in the preliminary design, the load distribution in the detail design, and the performance analysis. The static and dynamic coefficients are analyzed for strap on booster, body and strap on booster-body interface characteristics. A detail analysis is required during the detail design phase, but a rapid analysis is better in the preliminary design. Therefore, the database code, based on the theory and experimental datum, is useful to analyze the variety of models during the preliminary design phase, and the computational aerodynamic code is required to calculate the detail load distribution during the detail design phase. In this computational aerodynamic code, based on the database of theoretical and experimental datum, have been developed.
김재수,우철훈,김종록,김태훈,이상수 朝鮮大學校 機械技術硏究所 2005 機械技術硏究 Vol.8 No.2
고속으로 운항하는 비행체에는 구조상 바퀴간이나 폭탄장착부 등에 공동이 존재하게 되며, 난류 전단층에 의한 심한 압력진동과 공진현상이 일어나게 된다. 이러한 공진 현상들은 공동 주위의 구조물에 손상을 줄 수 있으며, 공기역학적 성능 및 안정성에 나쁘게 작용할 수가 있다. 본 논문에서는 비정상, 압축성의 2차원 축대칭과 3차원 Unsteady Reynolds -Averaged Navier-Stokes(RANS)방정식에 k- u난류 모델을 적용하여 종방향 진동이 지배적인 세장비(L/D)가 3인 공동에 폭비(W/D)를 1~5까지 증가시키며 수치 계산을 수행하였다. 이를 Rossiter 공식에 기초한 무차원 진통수와 Xin Zhang and Edwards의 실험결과로 비교 및 검증하였다. 그리고 2차원과 3차원의 각기 다른 유동현상을 SPL값을 이용한 FFT분석과 streamline을 통하여 비교 분석하였다. High-speed flight vehicles have cavities such as wheel wells and bomb bays. Supersonic cavity flow of high Reynolds number is characterized by pressure oscillation due to turbulent shear layer, cavity geometry, and resonance phenomenon based on external flow conditions. Resonance phenomena can damage the structures around the cavity and negatively affect aerodynamic performance and stability. In the present study, we performed numerical analysis of cavities by applying the k-u turbulence model to the unsteady, compressible, two dimensional and three dimensional Reynolds-Averaged Navier-Stokes(RANS) equations. The Strouhal numbers of the cavities were compared and verified by Rossiter's equation and experimental values of Xin Zhang and Edwards. The cavity model used for numerical calculation had a depth(D) of 15mm, cavity L/D of 3, width to depth ratio(W /D) was 1.0 to 5.0 for three dimensional analysis. Based on the PSD(Power Spectral Density) analysis of the pressure variation at the cavity floor, the dominant frequency was reasonable in comparison to the results of Rossiter and Xin Zhang & Edwards.