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[論文] 4-Stroke 디젤엔진의 性能豫測에 關한 硏究-熱發生Model을 使用한 Cycle Simulation-
오태식(T.S.Oh),오세종(S.Z.Oh),양재신(J.S.Yang) 한국자동차공학회 1982 오토저널 Vol.4 No.2
It is well known to diesel engineer. that the heat release pattern is one of the most important factors affecting engine performance. Thorough research in heat release pattern has materially helped the progress in high. speed diesel engine development. This paper is based on the research conducted at KAIST and Daewoo Heavy Industry last year. The purpose of this paper is to determine the heat release pattern in combustion chamber of MANM type, the famous low-noise engine.<br/> Thermodynamic cycle simulation was performed using Whitehous-Way's heat release pattern with modified coefficients and Annand's heat transfer model. Instantaneous temperature and pressure of gas in cylinder could be det ermined by the numerical solution of simultaneou. s equation of mass conservation, equation of energy conservation, and state equation of ideal gas. Calculated results were compared with measured values in some details emphasizing upon the factors affecting rate of heat release.<br/> The agteement was fairly good and revealed why M type should have lower burning velocity at the early part of combustion inspite of high injection rate. Additional results by parametric studies were given in relation to fuel injection conditions for further application to engine development.
백선우(S.W. Back),이관중(K.J. Yee),오세종(S.J. Oh) 한국전산유체공학회 2009 한국전산유체공학회지 Vol.14 No.1
Ice accretion may occur when the sold surface passes through the clouds containing supercooled water droplets. In the case of aircraft, it can result in serious performance degradation and safety hazard. In this study, numerical analysis code has been developed to predict the rime ice shapes on a 2-D airfoil and the computation results are validated against experimental data of NASA and other computation results of well-known ice prediction code, LEWICE. In addition, the effects of various numerical parameters on the ice shape have been systematically investigated.
항공기 Nacelle/pylon 위치에 따른 Shock-Buffet 현상의 수치적 연구
김성환(S.H. Kim),이관중(K.J. Yee),오세종(S.J. Oh) 한국전산유체공학회 2014 한국전산유체공학회 학술대회논문집 Vol.2014 No.11
The shock buffet on a transonic transport aircraft are negative factors that reduce the aerodynamic performance of aircraft. The parametric studies were performed for position of nacelle/pylon to estimate the trend of flow mechanism under the wing that affects shock buffet. To generate external mesh of aircraft configuration that change the position of nacelle, snappyHexMesh provided in OpenFOAM was applied. Implicit density-based solver(ISAAC) was used for flow analysis. The change of nacelle position along horizontal direction dynamically affected the aerodynamic performance of transonic transport aircraft as comparing that of vertical direction. As a result of the parametric study of nacelle/pylon position, it was confirmed that the optimal position of nacelle can be obtained by aerodynamic design.
로터 공력 해석을 위한 Actuator Surface Method 개선 연구
박재영(J.Y. Park),강선오(S.O. Kang),태명식(M.S. Tai),오세종(S.J. Oh),박동훈(D.H. Park) 한국전산유체공학회 2019 한국전산유체공학회지 Vol.24 No.2
In this study, improvements on up-to-date actuator surface method are proposed to enhance the prediction capability and universality for rotor aerodynamic analysis. In order to improve accuracy for analysis of high-solidity rotor, the correction equation for reference line velocity was newly derived to take into account influences of neighboring blades. To describe more realistic flow field and wake around blades, source-doublet panel method was adopted to calculate the momentum source distribution along chord-wise direction which reflects the characteristics of sectional airfoil and flow condition. The validity of proposed methods is evaluated by carrying out the analyses for rectangular wing and open rotor, and comparing with available experimental and computational results. It is confirmed that suggested methods can provide improvement on prediction of velocity field and wake trajectory, as well as aerodynamic performance.
항공기 Nacelle/pylon 위치에 따른 Shock-buffet 현상의 수치적 연구
김성환(S.H. Kim),이관중(K.J. Yee),오세종(S.J. Oh) 한국전산유체공학회 2014 한국전산유체공학회지 Vol.19 No.3
The shock buffet on a transonic transport aircraft are negative factors that reduce the aerodynamic performance of aircraft. The parametric studies were performed for position of nacelle/pylon to estimate the trend of flow mechanism under the wing that affects shock buffet. To generate external mesh of aircraft configuration that change the position of nacelle, snappyHexMesh provided in OpenFOAM was applied. Implicit density-based solver(ISAAC) was used for flow analysis. The change of nacelle position along horizontal direction dynamically affected the aerodynamic performance of transonic transport aircraft as comparing that of vertical direction. As a result of the parametric study of nacelle/pylon position, it was confirmed that the optimal position of nacelle can be obtained by aerodynamic design.
비정상 용출 및 중첩 패널 기법을 이용한 비행체의 피치 동안정 미계수 예측
태명식(M.S. Tai),강선오(S.O. Kang),오세종(S.J. Oh),박동훈(D.H. Park) 한국전산유체공학회 2019 한국전산유체공학회지 Vol.24 No.1
In general, it takes large time and cost to obtain dynamic stability derivatives of flight vehicles experimentally or numerically. In this study, the pitching dynamic derivatives of aircrafts are predicted by using source-doublet panel method and evaluate its practicality. A free-wake panel method is used for unsteady aerodynamic analysis of an aircraft in forced harmonic pitch oscillation. A treatment for wake-body interaction is applied to take into account the effect of wake from a main wing on a fuselage or tail wing. Calculations are carried out for a single rectangular wing, standard dynamic model(SDM), and DLR-F12 geometries. The dynamic derivatives are predicted based on the time history of the normal force and pitching moment. The unsteady panel method is validated by using numerical and experimental data in literatures and the results of Euler computation using commercial CFD code. For both the time history and predicted dynamic derivatives, the results show reasonable agreement with available experimental data and CFD results. The effect of Mach number and reduced frequency is examined for the SDM case. Within the Mach number range studied, the dynamic derivatives increase with Mach number which is consistent with the tendency observed in the previous studies. The dynamic derivatives are found to be relatively insensitive to the reduced frequency. The results show that the method of the present study provides reasonable accuracy and good efficiency for estimating the dynamic derivatives.