• The Journal of the Acoustical Society of Korea
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• v.38 no.5
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• pp.511-521
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• 2019

In this study, we theoretically study the acoustic scattering of an obliquely incident plane wave from a finite elastic cylindrical shell. A heuristic scattering method of Ye [Z. Ye, J. Acoust. Soc. Am. 102, 877-884 (1997)] for a finite fluid cylinder is extended into a finite elastic cylindrical shell since no analytic solutions exist in the finite cylinder. The elastic cylindrical shell is modeled with the 3D elastic wave theory considering internal fluid. Using the derived analytic solution, we observe the effect of the internal fluid on the scattering field, the scattering field for the Rayleigh parameter, and the far-field scattering function for the elastic property of the cylindrical shell.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2004.10a
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• pp.121-125
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• 2004

The effectiveness of the pogo suppression device (PSD) installed at the piping system simulating the fuel supply lines of the rocket engines was investigated. The system response defined as the ratio of the flow rate to the pressure in the main tube was obtained for various PSD gas volumes $(0,\;0.5,\;1,\;2\times10^{-6}\;m^3)$. Existence of a gas volume in the PSD reduced the system resonance frequency. With a larger gas volume, the resonance frequency became lower, but only slightly, though the fluctuations of the main tube pressure and the flow rate damped down considerably

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2004.10a
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• pp.9-12
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• 2004

A numerical simulation is presented for investigating the effects of pressure ratio of $D_2$ injector to supersonic nozzle on the Population inversion in the DF chemical laser cavity, while a latins concurrently takes place. In this study, these phenomena are investigated by means of analyzing the distributions of the DF excited molecules, while simultaneously estimating the maximum small signal gains and power in the DF chemical laser cavity. Major results reveal that the higher $D_2$ injection pressure provides a favorable condition for $DF^{(1)}$-$DF^{(0)}$ transition to generate the higher power laser beam.

• Journal of the Korean Society of Propulsion Engineers
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• v.9 no.2
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• pp.62-69
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• 2005

The design method to calculate the main features of propellant tank pressurization system during the development procedure of propellant feed system of the liquid rocket engine was suggested. We have considered the influences of parameters of pressurization gas on the efficiency of the thermodynamic processes in the tank. The optimum value of temperature and velocity of pressurization gas at the entrance of tank are obtained by the suggested way.

• Journal of the Korean Society of Propulsion Engineers
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• v.4 no.4
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• pp.26-35
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• 2000

This paper depicts the computational results for the axisymmetric subsonic/sonic ejector systems with a second throat. The numerical simulations are based on a fully implicit finite volume scheme of the compressible Reynolds-Averaged Navier-Stokes equations in a domain that extends from the stagnation chamber to the ejector diffuser exit. In order to obtain practical design factors for the subsonic/sonic ejector systems which are applicable to industrial vacuum pumps, the ejector throat area, the mixing section configuration, and the ejector throat length are changed in computations. For the subsonic/sonic ejector systems operating in the range of low operation pressure ratios, the effects of the design factors on the vacuum performance of the secondary chamber are discussed.

• Journal of the Korean Society of Propulsion Engineers
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• v.4 no.4
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• pp.1-8
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• 2000

For the purpose of a cost effective design of practical subsoni $c^ersonic ejector systems, an experiment was carried out using a superheated steam as a primary driving flow. The superheated steam jet was produced by several different kinds of subsonic and supersonic nozzles. The secondary flow of atmospheric air inside a plenum chamber was drawn into the primary steam jet. The vacuum performance of the plenum chamber was investigated for a wide range of the ejector operation pressure ratio. The result showed that the static pressure of the mixed flow at the ejector throat is only a function of the ejector operation pressure ratio, regardless of the primary nozzle type employed.ed.

• Journal of the Korean Society of Propulsion Engineers
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• v.4 no.4
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• pp.70-77
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• 2000

Supersonic Dual Bell Nozzle (SDBN) is an altitude-adaptive propulsion nozzle achieved only by a nozzle wall inflection. In order to investigate the altitude adaptive capability and the effectiveness of this nozzle concept, the present study addresses a computational work of the flow through SDBN. Several types of the SDBNs are tested for a wide range of the pressure ratio which covers from an over-expended flow to a fully under-expended flow at the exit of the SDBN. Axisymmetric, compressible, Wavier-Stokes equations are numerically solved using a fully implicit finite volume differencing scheme. The present computational results reveal that the base nozzle length affects the shock wave system occurring inside SDBN. For a quit wide range of the pressure ratio the flow separation occurs at the nozzle inflection point. It is found that the maximum thrust coefficient is obtainable for the correct expansion state at the exit of SDBN.

• Journal of the Korean Society of Propulsion Engineers
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• v.19 no.3
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• pp.65-72
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• 2015

In present study, a supersonic inlet for dual mode ramjets or RBCC/TBCC engines with a wide range of flight Mach numbers is designed. A conical variable inlet configuration is chosen for the inlet design. Geometric relations with angles of compression cones and conical shock waves are used for the design of the inlet configuration. The performance of the supersonic inlet is confirmed by the numerical analysis. The capture area ratio is maintained around 100% from Mach 3 to 8 conditions.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.03a
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• pp.173-181
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• 2008

Gas turbine engine for aircraft are usually operated at the altitude condition which is quite different from the ground condition. In order to measure the precise performance data at the altitude condition, the engine should be tested at the altitude condition by a real flight test or an altitude simulation test with an altitude test facility. In this paper describes the design of altitude test facility for turbo shaft engine. This facility will be located in test cell #2 at the Korea Aerospace Research Institute. Test Cell #2 will be used for altitude testing engines with mass flow rate up to 40kg/s and inlet temperatures in the range from $-65^{\circ}C$ to $200^{\circ}C$. The existing compressor/exhauster station with heater & cooler system will be used to simulate altitude conditions in Test Cell #2.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.11a
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• pp.326-329
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• 2008

DARPA's hypersonic propulsion program VULCAN is aimed for development of Mach 4+ capable engine by combining current production turbofan engine such as F119 with CVC (Constant Volume Combustion) engine. Final goal is a TBCC(Turbo-based Combined Cycle) engine by combining with dual mode ramjet/scramjet engine. CVC is a common designation of new concept of high efficiency engines, such as Pulse Detonation Engine (PDE) or Continuous Detonation Engine (CDE), which use the detonation as a combustion mechanism. Present paper introduces the internationally collaborative research activities carried out in Aerospace Combustion and Propulsion Laboratory of the department of Aerospace Engineering of the Pusan national University.