• Title/Summary/Keyword: Numerical propulsion system simulation

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Optimal Output Tracking Control Simulation for Thrust Control of an Open-cycle Liquid Propellant Rocket Engine (개방형 액체로켓엔진의 추력제어를 위한 최적출력 추종제어 시뮬레이션)

  • Cha, Jihyoung;Cho, Woosung;Ko, Sangho
    • Journal of the Korean Society of Propulsion Engineers
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    • v.24 no.2
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    • pp.52-60
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    • 2020
  • This paper deals with an optimal output tracking control for open-cycle liquid propellant rocket engine. For this purpose, we modeled simplified mathematical model of open-cycle liquid propellant rocket engine and designed optimal output feedback control system using combustion chamber pressure. For design the closed-loop system of open-cycle liquid propellant rocket engine, we designed optimal output feedback linear quadratic tracking control system using the linearized model and demonstrated the performance of the controller through numerical simulation.

Two-dimensional Numerical Simulation of a Pulsed Heat Source High Temperature Inert Gas Plasma MHD Electrical Power Generator

  • Matsumoto, Masaharu;Murakami, Tomoyuki;Okuno, Yoshihiro
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2008.03a
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    • pp.589-596
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    • 2008
  • Performance of a pulsed heat source high temperature inert gas plasma MHD electrical power generator, which can be one of the candidates of space-based laser-to-electrical power converter, is examined by a time dependent two dimensional numerical simulation. In the present MHD generator, the inert gas is assumed to be ideally heated to about $10^4K$ pulsed-likely within short time(${\sim}1{\mu}s$) in a stagnant energy input volume, and the energy of high temperature inert gas is converted to the electricity with the medium of pure inert gas plasma without seeding. The numerical simulation results show that an enthalpy extraction ratio(=electrical output energy/pulsed heat energy) of several tens of % can be achieved, which is the same level as the conventional seeded non-equilibrium plasma MHD generator. Although there still exist many phenomena to be clarified and many problems to be overcome in order to realize the system, the pulsed heat source high temperature inert gas MHD generator is surely worth examining in more detail.

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Investigation on the Off Design Performance of a Transonic Compressor with Circumferential Grooves

  • Zhu, Jianhong;Piao, Ying;Zhou, Jianxing;Qi, Xingming
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2008.03a
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    • pp.66-71
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    • 2008
  • Two cases with circumferential grooves were designed for a transonic compressor, and 3-D numerical simulations were conducted for stall mechanism at three representative speeds. A conclusion can be drawn from the comparison between compressors with or without casing treatment that: with the rising of rotation speed, stall margin increases dramatically under the help of casing treatments, and the case with middle grooves has reasonable compromise between stall margin increment and efficiency cutting. At lower speed, the increment reduces, and grooves at the back of blade tip have more influence on stall margin. Further investigation shows there is a transition in mechanism of compressor stall with the decline of rotational speed: at high rotation speed, the expansion of stall margin mainly results from the suppression of tip leakage vortex by casing treatments, yet it benefits more from the depression of boundary layer separation from suction surface of blade tip.

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Numerical prediction analysis of propeller bearing force for full-scale hull-propeller-rudder system

  • Wang, Chao;Sun, Shuai;Li, Liang;Ye, Liyu
    • International Journal of Naval Architecture and Ocean Engineering
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    • v.8 no.6
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    • pp.589-601
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    • 2016
  • The hybrid grid was adopted and numerical prediction analysis of propeller unsteady bearing force considering free surface was performed for mode and full-scale KCS hull-propeller-rudder system by employing RANS method and VOF model. In order to obtain the propeller velocity under self-propulsion point, firstly, the numerical simulation for self-propulsion test of full-scale ship is carried out. The results show that the scale effect of velocity at self-propulsion point and wake fraction is obvious. Then, the transient two-phase flow calculations are performed for model and full-scale KCS hull-propeller-rudder systems. According to the monitoring data, it is found that the propeller unsteady bearing force is fluctuating periodically over time and full-scale propeller's time-average value is smaller than model-scale's. The frequency spectrum curves are also provided after fast Fourier transform. By analyzing the frequency spectrum data, it is easy to summarize that each component of the propeller bearing force have the same fluctuation frequency and the peak in BFP is maximum. What's more, each component of full-scale bearing force's fluctuation value is bigger than model-scale's except the bending moment coefficient about the Y-axis.

Study on Simulation Method for Combustion Flow Field with the Moving Boundary of Solid Propellants (이동 경계면을 가진 고체 추진제 연소 유동장의 해석 기법 연구)

  • Sung, Hyung-Gun;Park, Sol;Hong, Gi-Cheol;Roh, Tae-Seong;Choi, Dong-Whan
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2007.11a
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    • pp.229-232
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    • 2007
  • A numerical method for the moving boundary required in analysis of the combustion phenomenon of the solid propellant has been studied. The ghost cell extrapolation has been used in the Eulerian coordinate system. The Lagrangian method has been used in Non-Eulerian coordinate system. Results of the numerical analysis were verified by comparing to theoretical results of 1-D free-moving piston in the pipe.

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Investigation of the shock structural formation of the supersonic nozzle jet with longitudinal variation of coaxial pipe location

  • Roh, Sung-Cheoul;Park, Jun-Young;Kim, Soo-Yong
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2004.03a
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    • pp.784-788
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    • 2004
  • A visualization study of shock formation of the supersonic jet nozzle using a Shadowgraph Method (SM) was carried out to investigate the effect of the longitudinal variation of coaxial pipe end tip position inside the supersonic nozzle. The experiment was performed for the Mach number range from 1.1 to 1.2 at nozzle exit. The well known shock cell structure was shown with the pipe end located deep inside the nozzle for the studied Mach number. With the pipe end approaches nozzle exit, it was found that the shock cell structure disappeared and turned into complex formation. In order to understand the mechanism of the shock structural change, computational simulation was carried out using the Navier-Stokes solver, FLUENT. Topological sketch was added with an aid of the visualization and the numerical simulation.

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A numerical study on manoeuvrability of wind turbine installation vessel using OpenFOAM

  • Lee, Sungwook;Kim, Booki
    • International Journal of Naval Architecture and Ocean Engineering
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    • v.7 no.3
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    • pp.466-477
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    • 2015
  • In this study, a numerical prediction method on manoeuvrability of Wind Turbine Installation Vessel (WTIV) is presented. Planar Motion Mechanism (PMM) captive test for the bare hull of WTIV is carried out in the model basin and compared with the numerical results using RANS simulation based on Open-source Field Operation And Manipulation (OpenFOAM) calculation to validate the developed method. The manoeuvrability of WTIV with skeg and/or without skeg is investigated using the numerical approach along with the captive model test. In the numerical calculations, the dynamic stability index which indicates the course keeping ability is evaluated and compared for three different hull configurations i.e. bare hull and other two hulls with center skeg and twin skeg. This paper proves that the numerical approach using RANS simulation can be readily applied to estimate the manoeuvrability of WTIV at the initial design stage.

아크 용접에서 구동력에 따른 열 및 물질 유동에 관한 연구

  • 김원훈;나석주
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 1996.11a
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    • pp.27-41
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    • 1996
  • In this study the heat transfer and fluid flow of the molten pool in stationary gas tungsten arc welding using argon shielding gas were investigated. Transporting phenomena from the welding arc to the base material surface, such as current density, heat flux, arc pressure and shear stress acting on the weld pool surface, were taken from the simulation results of the corresponding welding arc. Various driving forces for the weld pool convection were considered, self-induced electromagnetic, surface tension, buoyancy, and impinging plasma arc forces. Furthermore, the effect of surface depression due to the arc pressure acting on the molten pool surface was considered. Because fusion boundary has a curved and unknown shape during welding, a boundary-fitted coordinate system was adopted to precisely describe the boundary for the momentum equation. The numerical model was applied to AISI 304 stainless steel and compared with the experimental results.

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DEVELOPMENT OF SIMULATION TOOL FOR ORBITAL MOTION OF METEOROID STREAM PARTICLES (METEOROID STREAM 입자들의 궤도 운동 시뮬레이션 TOOL 개발)

  • 김방엽
    • Journal of Astronomy and Space Sciences
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    • v.17 no.1
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    • pp.107-116
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    • 2000
  • This paper presents the preliminary survey and simulation results of the prediction of Leonid stream's orbital motion. Based on the model survey on eject velocity and perturbation of meteoroid particles, a simulation program was developed and applied to orbital motion of Leonid stream. The Jones ejection distribution model was used to describe the particle's eject velocity and the orbital dynamic model includes perturbations of major planet's gravity. DE405 ephemeris file generated by Solar System Dynamics Group at Jet Propulsion Laboratory in NASA was used for the planet's ephemeris calculations. Solar radiation pressure were also considered in the simulation and 8th order Runge-Kutta algorithm was used a numerical integration method.

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A Numerical Analysis of Thrust Development and Control using Multi-Nozzle (다발 노즐을 사용한 추력 발생 제어에 관한 수치적 연구)

  • Park, Hyung-Ju;Sung, Hong-Gye
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2010.05a
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    • pp.288-291
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    • 2010
  • Numerical analysis was conducted on thrust vector control using multi-nozzle system. The nozzle using flow valve switch to control mass flow of multi scarfed nozzle to manage thrust was considered. The operating characteristics of scarfed nozzle, thrust component and moment of multi nozzle in terms of mass flow rate were investigated by three dimensional flow simulation.

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