• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.36 no.4
• /
• pp.328-336
• /
• 2008

The shock tunnel as a hypersonic ground test facility was designed, constructed and its performance test was conducted to reproduce the high speed flow which the hypersonic propulsion system is encountered. The design points were understood and the conceptual design was completed using the quasi one dimensional operation analysis code. After that, the specific performance and compartment design were completed using CFD simulation as the part analysis. The facility was then constructed according to those design results and the performance test was conducted for various operation conditions. In this paper, we suggested the compartment design method using CFD analysis, construction process and various performance test results in detail.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.36 no.4
• /
• pp.321-327
• /
• 2008

The shock tunnel as a hypersonic ground test facility was designed, constructed and its performance test was conducted to reproduce the high speed flow which the hypersonic propulsion system is encountered. The design points were understood and the conceptual design was completed using the quasi one dimensional operation analysis code. After that, the specific performance and compartment design were completed using CFD simulation as the part analysis. The facility was then constructed according to those design results and the performance test was conducted for various operation conditions. In this paper, we suggested the design method of hypersonic shock tunnel including the conceptual and performance design using theoretical analysis and the quasi 1D Multi-species computational fluid dynamics code.

• 한국전산유체공학회:학술대회논문집
• /
• 1995.10a
• /
• pp.213-218
• /
• 1995

마하수 4일때 초음속 풍동의 벽면과 모델지지부의 간섭에 관해 연구하였다. 특히 모델지지부 주위에서의 충격파 형성과 sting, strut 그리고 second throat에서의 반사 충격파의 상호 작용에 연구의 촛점을 두었다. 수치 기법은 내재적 플럭스 차분 분할기법 (implicit flux-difference splitting technique)을 사용하였다. 2차원과 3차원 유동해석 결과로부터 모델지지부 후류의 유동에 미치는 diffuser 출구 경계조건의 영향을 알아보았다.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.44 no.6
• /
• pp.463-467
• /
• 2016

In this paper, acceleration and pressure exerted on a human model were measured under a supersonic condition in a shock tunnel. In order to measure these in an interference-free environment, free-fall technique with an electromagnet and a three-dimensional iron-powdered human model was used. Free-fall experiment was conducted at Mach 4 and the force acting on the model was obtained by calculating the displacement from the flow visualization images.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2011.04a
• /
• pp.391-394
• /
• 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.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2017.05a
• /
• pp.609-611
• /
• 2017

The hysteresis phenomena are frequently encountered in the wide variety of fluid flow systems of industrial and engineering applications. Hysteresis mainly appears during the transient change of pressure ratios, and this, in turn, influences the performance the supersonic wind tunnel. However, investigations on the hysteresis phenomenon particularly inside the supersonic wind tunnel are rarely studied. In the present study, numerical simulations are carried out to investigate hysteresis phenomenon of the shock waves inside the Supersonic Wind Tunnel. The unsteady, compressible flow through the supersonic wind tunnel is computationaly analyzed with an symmetric model. The Navier-Stokes equations are solved with Spalart-Allmaras turbulence model using a fully implicit finite volume scheme. The variaton in the flow field between the starting pressure ratio and operating pressure ratio of a supersonic wind tunnel is investigated in terms of hysteresis phenomenon.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.22 no.2
• /
• pp.52-58
• /
• 2018

Hysteresis phenomena are often encountered in a wide variety of fluid flow systems used in industrial and engineering applications. Hence, in recent years, a significant amount of research been focusing on clarifying the physics of the flow hysteresis appearing during the transient change of the pressure ratios and influencing the performance of the supersonic wind tunnel. However, investigations on the hysteresis phenomenon, particularly when it occurs inside the supersonic wind tunnel, are rare. In this study, numerical simulations were carried out to investigate the hysteresis phenomena of the shock waves encountered in a supersonic wind tunnel. The unsteady and compressible flow was analyzed with an axisymmetric model, and the N-S equations were solved by using a fully implicit finite volume scheme. The optimal pressure ratio was determined from the hysteresis curves, and the results can be utilized to operate the wind tunnel efficiently.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 1998.10a
• /
• pp.10-10
• /
• 1998

천음속 익형에서 발생하는 응축충격파와 경계층의 간섭을 피동제어 하여 항력감소에 대한 연구를 2.5$\times$7$\textrm{cm}^2$ 천음속 풍동에서 수행하였다. 익형표면에 설치한 정압공으로 정압을, 익형후방에 설치한 8개의 Pitot probe로 전압을 동시에 측정하여 충격파를 통한 에너지의 손실과 항력의 변화를 계산하였고, 또한 유동장과 충격파의 형상을 가시화하기 위해 슈리렌 가시화 시스템을 사용하였다. 실험은 NACA 0012 익형에서 기공률 변화에 따른 피동제어의 항력감소 초과를 조사한 다음 NACA 64-018 익형에서는 기공률과 공동의 크기의 변화가 미치는 효과를 연구하였다. 피동제어의 개념은 충격파가 발생하는 하부벽을 다공벽으로 만들고 그 아래를 공동으로 만들면 충격파 후방의 상대적으로 높은 압력이 기류의 일부를 공동으로 자연스럽게 유입시키고 다시 공동에서 낮은 압력의 충격파 상류로 유출시키는 것이다.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.46 no.8
• /
• pp.652-661
• /
• 2018

It is necessary to resolve the absolute velocity as well as Mach number to reflect the high temperature effect in high speed flow. So this region is classified as high enthalpy flows distinguished from high speed flows. Many facilities, such as arc-jet, shock tunnel, etc. has been used to obtain the high enthalpy flows at the ground level. However, it is difficult to define the exact test condition in this type of facilities, because some chemical reactions and energy transfer take place during the experiments. In the present study, a quasi 1D code considering the thermochemical non-equilibrium effect is developed to effectively estimate the test condition of a shock tunnel. Results show that the code gives reasonable solution compared with the results from the known experiments and 2D axisymmetric simulations.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2007.11a
• /
• pp.41-44
• /
• 2007

Ground test facility for the hypersonic propulsion system was designed, constructed and performance test was conducted. The design point was selected using quasi，1-Dimensional CFD analysis before the conceptual design for construction of hypersonic facility After that, specific designs for performance and components were completed using unit analysis CFD code and performance tests were conducted for the various operation conditions.