• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.44 no.2
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• pp.116-122
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• 2016

The performance characteristics of a TBCC engine considering the transition mode from a turbojet to a ramjet engine has been investigated. The performance of each engine was proposed and a transition mode of the TBCC engine has been evaluated by adjusting the operating rate of the ramjet engine and turbojet engine performance changes continuously. Based on the transition model, it was confirmed that the performance is continuously changed at various flight Mach numbers and altitudes. The performance characteristics including thrust and specific impulse considering various flight conditions and transition mode were analyzed, which testifies characteristics of the engine itself, as well as transition of the combined cycle.

• Journal of the Korean Society of Propulsion Engineers
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• v.8 no.3
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• pp.1-9
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• 2004

We conducted the firing test with the regenerative cooling LRE and calculated the heat flux from measured coolant temperature, that was compared with the heat flux predicted by previously developed numerical analysis method. The difference between the measured heat flux and the numerical calculation value was within nine percents. Therefore, developed numerical analysis method can be applied to the design/fabrication of a real LRE system. and, it was investigated that combustion pressure and mixture ratio have an Influence on the heat flux with a constant relation.

• Journal of the Korean Society of Propulsion Engineers
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• v.13 no.1
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• pp.58-71
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• 2009

The blast wave released during the initiation of energetic materials gives rise to pulse energy generation, characterized by a sudden increase of potential energy. A highly efficient energy source, sought from pulse-type lasers, may be utilized in various space propulsion and power applications. This paper introduces a scheme of utilizing the laser energy in 1) attitude control of a satellite requiring of a low thrust, 2) innovative laser-induced drug delivery, 3) implosion-based micro piston development, 4) deflecting and zapping of space debris for laser kill purpose, and 5) finally lunar detection using laser induced breakdown spectroscopy.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2003.10a
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• pp.253-256
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• 2003

The engine core of a 65hp-turboshaft engine for UAV is developed and modified into a 55lbf-turbojet engine. Since the core engine is installed with a propelling nozzle, which has the same mass flow characteristics as the power generator of the turboshaft engine its mechanical and aerodynamic characteristics are basically the same as those of the complete engine. Engine output is not shaft power but thrust force that is easier to measure. The core engine is very useful for core test purpose. Besides, the core engine itself can be directly used for propulsion of small air vehicles.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2003.10a
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• pp.53-56
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• 2003

This paper describes the general design procedure of cooling system for liquid rocket engine(LRE). From this design logic, cooling channels are designed and fabricated. The measured heat flux from firing test is similar to the heat flux predicted by design logic. Therefore, the proposed design procedure of cooling channel can be applied to real LRE system. Also the result of firing test indicates that combustion pressure and mixture ratio have an influence on the heat flux to be produced in combustion chamber.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.3
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• pp.85-94
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• 2003

A geosynchronous Satellite in general, has two momentum management logics to maintain its wheel momentum tin the stable region. The one is applied in order to control accumulative wheel momentum in the momentum dumping mode and the other is utilized in order to control attitude errors during the stationkeeping. In this paper, the momentum management logics are explained for dumping/sationkeeping mode and the logics are verified by simulation on the 3 attitude subsystem.

• Bulletin of the Society of Naval Architects of Korea
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• v.27 no.1
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• pp.73-83
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• 1990

A theorectical method is presented for the calculation of the effective wake in an axisymmetric sheared inflow. The effective wake is essential in the design of optimal propulsor and in the reduction of propulsor induced vibration and noise. The nominal wakes are mathematically modelled and the effective wakes are calculated using the computer program developed on the basis of the linear momentum theory. The results show that shear effects arc dominant near the hub and the effective wakes reveal some differences near the hub for the moderately and heavily loaded propulsors but they arc well coincided with the other experimental or theorectical results for the lightly loaded propulsors. To improve the results it may be necessary to consider nonlinear terms neglected in this study and body boundary condition on hub.

• Aerospace Engineering and Technology
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• v.12 no.1
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• pp.111-119
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• 2013

Conceptual design of RBCC (Rocket Based Combined Cycle) engine is performed through the thermodynamic cycle analysis. The engine is designed to take off at sea level and accelerate to Mach 8 at 30 km altitude. According to the flight speed, the engine operating modes are categorized into 3 modes : Ejectorjet (~ Mach 3), Ramjet (Mach 3~6), Scramjet (Mach 6~8). As a design result, the engine has a diameter of 1 m and a length of 6.7 m. In the prediction results, its maximum thrust is 16.5 ton. In Ramjet and Scramjet modes, design condition of the engine intake influence the engine thrust according to the flight speed.

• Transactions of the Korean Society of Mechanical Engineers
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• v.12 no.5
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• pp.1063-1070
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• 1988

The influence of the inlet pressure on bearing performance of tilting pad bearings in laminar regime is examined. A simple flow model is presented to calculate the inlet pressure in inlet flow that occurs at a short distance ahead of the bearing inlet. The bearing performances are obtained, load capacity, friction torque and lubricated flow-rate, etc, numerically for the inlet pressure boundary conditions with and without pressure jump. The computed results of both cases show that bearing performance and the optimum pivot position changes remarkably according to the bearing operating conditions. The influence of the inlet pressure on bearing performance must be considered to analyze the bearing performance precisely.

• Journal of the Korean Society of Propulsion Engineers
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• v.20 no.4
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• pp.87-93
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• 2016

In a Direct Connect(DC) mode altitude engine test, a labyrinth seal is set up between an air intake duct and an engine. The labyrinth seal plays a key role in mechanically isolating them, which contributes to the accurate measurement of thrust and the other component forces. However, when high vertical temperature gradient is generated in the supplied air in the duct, the isolation breaks down. In this paper, a labyrinth seal control device is designed and installed in an effort to eliminate the issue. Test result shows the device successfully gets rid of the contact problem even when high vertical temperature gradient is produced.