• Title/Summary/Keyword: 등 마하수

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터보프롭엔진의 정상상태 탈설계점 성능해석 기법에 관한 연구

  • 공창덕;신현기;기자영
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 1999.10a
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    • pp.24-24
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    • 1999
  • 소·중형 상업용 항공기나 초등 훈련기용으로 많이 이용되고 있는 터보프롭엔진의 정상상태 성능해석을 위한 프로그램을 개발하였다. 프로그램의 검증을 위하여 지상정지조건에서의 성능 및 비행마하수에 따른 출력 등을 상용 정상상태 해석 프로그램인 TURBOMARCH 해석결과와 비교하였다. 비교결과 각 구성품의 입 ·출구 온도 및 압력, 출력 등에서는 약 3%이하의 오차율을 보였으며, 마하수 변화에 따른 출력 비교에서도 최대오차율이 2.4%로 프로그램의 신뢰성을 확인하였다. 개발된 프로그램을 이용하여 비행마하수 0.2, 80% 동력터빈 회전수에서 가스발생기 회전수를 5% 간격으로 나누어 부분부하 성능해석을 수행하였으며, 동력터빈 회전수에 따른 성능해석도 수행하였다.

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소형항공기용 터보프롭엔진의 성능모사에 관한 연구

  • 공창덕;신현기;기자영
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2000.04a
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    • pp.27-27
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    • 2000
  • 소, 중형 상업용 항공기나 초등 훈련기용으로 많이 이용되고 있는 터보프롭엔진의 성능해석을 위한 프로그램을 개발하였다. 대상엔진으로는 국내 최초의 초등훈련기인 KT-1의 추진기관인 PT6A-62엔진을 선정하였고 프로그램의 검증을 위하여 지상정지조건에서의 성능, 고도에 따른 성능 및 비행마하수에 따른 성능, 그리고 고도와 비행마하수를 동시에 고려한 성능 등을 상용 프로그램인 GASTURB 및 제작사에서 제시한 성능데이터와 그 해석결과를 비교하였다. 개발된 프로그램을 이용하여 비행마하수 0.2, 100% 동력터빈 회전수에서 가스발생기 회전수를 75%에서 105%까지 5% 간격으로 나누어 부분부하 성능해석을 수행하였다. 또한 연료유량의 변화에 대한 천이상태 성능해석도 수행하였다.

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Numerical Study on the Effect of Non-Equilibrium Condensation on Drag Divergence Mach Number in a Transonic Moist Air Flow (천음속 익형 유동에서 비평형 응축이 Drag Divergence Mach Number에 미치는 영향에 관한 수치 해석적 연구)

  • Choi, Seung Min;Kang, Hui Bo;Kwon, Young Doo;Kwon, Soon Bum
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.40 no.12
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    • pp.785-792
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    • 2016
  • In the present study, the effects of non-equilibrium condensation on the drag divergence Mach number with the angle of attack in a transonic 2D moist air flow of NACA0012 are investigated using the TVD finite difference scheme. For the same ${\alpha}$, the maximum upstream Mach number of the shock wave, Mmax, and the size of supersonic bubble decrease with the increase in ${\Phi}_0$. For the same $M_{\infty}$, ${\Phi}_0$, and $T_0$, the length of the non-equilibrium condensation zone ${\Delta}_z$ decreases with increasing ${\Phi}_0$. On the other hand, because of the attenuating effect of non-equilibrium condensation on wave drag, which is related to the interaction between the shock wave and the boundary layer, the drag coefficient $C_D$ decreases with an increase in ${\Phi}_0$ for the same $M_{\infty}$ and ${\alpha}$. For the same ${\alpha}$, $M_D$ increases with increasing ${\Phi}_0$, while $M_D$ decreases with an increase in ${\alpha}$.

Numerical Investigation of the Lateral Jet Effect on the Aerodynamic Characteristics of the Missile: Part I. Jet Flow Condition Effect (측 추력 제트가 미사일의 공력특성에 미치는 영향에 관한 연구 : Part I. 제트 유동특성 영향)

  • Min, Byung-Young;Lee, Jae-Woo;Byun, Yung-Hwan;Hyun, Jae-Soo;Kim, Sang-Ho
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.32 no.8
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    • pp.64-71
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    • 2004
  • A computational study on the supersonic flow around the lateral jet controlled missile has been performed. For this purpose a three dimensional Navier-Stokes computer code(AADL3D) has been developed and case studies have been performed by comparing the normal force coefficient and the moment coefficient of a missile body for different jet flow conditions including jet pressure and jet Mach number. The results show different behavior of normal force and moment variation according to jet pressure variation and jet Mach number variation. From the detailed flow field analyses, it is verified that most of the normal force loss and the pitching moment generation are taken place at the low-pressure region behind the jet nozzle. Furthermore, it is shown that the pitching moment can be efficiently reduced by obtaining the lateral thrust through higher jet Mach number rather than through high jet pressure.

A Numerical Study of Channel Shape and Mach Number Effects on Transonic Combustion (채널형상과 마하수가 천음속 연소에 미치는 영향에 대한 수치해석적 연구)

  • Lee, Jang-Chang
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.33 no.11
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    • pp.65-73
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    • 2005
  • The compressible flow of reactive fluid is investigated by using the transonic small-disturbance (TSD) model and the one-step first-order Arrhenuis chemical reaction. The fluid flow is restricted to dilute premixed reactions with small heat release. The effects of channel shape and Mach number on transonic combustion are studied by numerical analysis. The results show that the channel divergence increases the chemical reaction within the given channel length whereas the channel convergence inhibits the chemical reaction near the outlet and that increasing the inlet flow Mach number at a fixed reaction rate causes the flow acceleration in a diverging channel and the appearance of weak shock waves which do not show in the inert flow case. It also helps to increase the pressure and temperature near the diverging channel outlet and to consume the reactant within the given channel length.

Experimental Study on the Supersonic Air Intake at Mach 4 (마하4 초음속 공기 흡입구 유동 특성에 관한 실험적 연구)

  • Lee Hyoung-Jin;Jeung In-Seuck;Aso Shigeru
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • v.y2005m4
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    • pp.394-398
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    • 2005
  • Ramjet engine have been usually operated on Mach $1.5\sim3$ as the vehicle of supersonic cruising engine and studied about the higher performance above Mach 4. The research of Duel mode Scramjet engine which have duel operating mode of ramjet/Scramjet are in progress actively nowadays. This paper suggests the effect the flow characteristics and the effects of back pressure, angle of attack, angle of yow on the supersonic air intake on mach 4 through the Schlieren/Oil flow visualization, and pressure measurement on experimental model.

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Analytical Study on Performance Parameters of High Speed Propulsion (Ramjet/Scramjet) (초고속 순항 추진기관(램제트/스크램제트)의 성능인자에 대한 해석적 연구)

  • Byun Jong-Ryul;Sung Hong-Gye;Yoon Hyun-Gull
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2005.11a
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    • pp.141-146
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    • 2005
  • This paper presents a theoretical analysis of a ramjet and scramjet engine according to flight Mach numbers. The main objective of this study is to give physical understanding on the performance parameters and to provide a more unified treatment of the fundamentals of ramjet and scramjet propulsion, mainly based on analytical methods. The effects of flight Mach number, inlet characteristics, and combustion on the performance of ramjet and scramjet are analysed. The cycle analysis are conducted on both combustors with constant pressure and with constant cross-section area, on which comparisons are made. Also the optimal Mach number at the entry of the combustor is studied.

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Defect Diagnostics of Gas Turbine Engine with Mach Number and Fuel Flow Variations Using Hybrid SVM-ANN (SVM과 인공신경망을 이용한 속도 및 연료유량 변화에 따른 가스터빈 엔진의 결함 진단 연구)

  • Choi, Won-Jun;Lee, Sang-Myeong;Roh, Tae-Seong;Choi, Dong-Whan
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2006.11a
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    • pp.289-292
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    • 2006
  • In this paper, the hybrid algorithm of Support Vector Machine md Artificial Neural Network is used for the defect diagnostics algorithm for the aircraft turbo-shaft engine. The results of learning of ANN, especially, accuracy or speed of convergence are sensitive to the number of data, so a comparison between design point and off-design area, especially, Mach number and fuel flow variable area, is essential research. From application results for diagnostics of gas turbine engine, it was confirmed that the hybrid algorithm could detect well in the of-design area as well as design point.

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The consideration about pressure on surface of cone shape in experiments of supersonic wind tunnel I (초음속풍동실험에서 원뿔형상의 표면에서 측정되는 압력에 대한 고찰 I)

  • Lee, Jae-Ho;Choi, Jong-Ho;Yoon, Hyun-Gull;Kim, Kyu-Hong
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2011.04a
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    • pp.391-394
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    • 2011
  • In this paper, the shock angle and effect had been compared with numerical data within supersonic area at an forebody such as missiles or an aircraft. By using supersonic wind tunnel in Seoul National University, The shock position and magnitude were measured in the model of cone shape according to mach number. The experiment had been conducted at mach number 2.0, 3.0, and 3.8. As a result, the shock position and magnitude are different from flow velocity, AOA, and AOS in some cases blockage effect had occurred.

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A Study on Improvement γ-Reθt Model for Hypersonic Boundary Layer Analysis (극 초음속 경계층 해석을 위한 γ-Reθt모델 개선 연구)

  • Kang, Sunoh;Oh, Sejong;Park, Donghun
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.48 no.5
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    • pp.323-334
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    • 2020
  • Since boundary layer transition has a significant impact on the aero-thermodynamic performance of hypersonic flight vehicles, capability of accurate prediction of transition location is essential for design and performance analysis. In this study, γ-Reθt model is improved to predict transition of hypersonic boundary layers and validated. A coefficient in the production term of the intermittency transport equation that affects the transition onset location is constructed and applied as a function of Mach number, wall temperature, and freestream stagnation temperature based on the similarity numerical solution of compressible boundary layer. To take into account a Mach number dependency of transition onset momentum thickness Reynolds number and transition length, additional correlation equations are determined as function of Mach number and applied to Reθc and Flength correlations of the baseline model. The suggested model is implemented to a commercial CFD code in consideration of practical use. Analysis of hypersonic flat plate and circular cone boundary layers is carried out by using the model for validation purpose. An improvement of prediction capability with respect to variation of Mach number and unit Reynolds number is identified from the comparison with experimental data.