• Journal of the Korean Society of Propulsion Engineers
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• v.9 no.4
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• pp.48-54
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• 2005

An experimental study was carried out to investigate the effect of film cooling in the lab-scale liquid rocket engine using liquid oxygen(LOx) and Jet A-1(Jet engine fuel) as propellants. Film coolants(Jet A-1 and water) was injected through the film cooling injector. The outside wall temperature of the combustor and film cooled length were determined for chamber pressure, mixture ratio, and the different geometries(injection angle) with the percent film coolant flow rate. The loss of characteristic velocity was determined for the case of film cooling with water and Jet A-1. As chamber pressure increased, the outside wall temperature increased in the nozzle but unchanged over the 9 percent film coolant flow rate for the combustion chamber used in this study. Characteristic velocity wasn't affected with the mixture ratio over the 9 percent film coolant flow rate.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.1068-1071
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• 2017

The turbine exhaust system consists of a turbine flange, heat exchanger, exhaust duct and thrust nozzle. Heat exchanger is used for the launch vehicle because of the advantage of reducing the weight of the helium gas and the storage tank by using the heat exchanger pressurization method compared to the cold gas pressurizing method. Since the gas generator is combusted in fuel-rich condition, the soot is contained in the combustion gas. Hence, the heat exchanger should be designed considering the reduction of the heat exchange efficiency due to the soot effect. In addition, the uncertainty of the heat exchange calculation and the evaluation of the influence of the combustion gas soot on the heat exchange can not be completely calculated, so the design requirements must include a structure that can guarantee and control the temperature of the heat exchanger outlet. In this paper, it is described that the component allocation, the design method considering the manufacture of internal structure, the advantages of new concept of nozzle design.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.258-265
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• 2017

At the early stage of the development of high speed propulsion systems, the designers suffer from the lack of both the quantity and the quality of test data. In that situation, the associated uncertainties could not be modeled as probabilistic distribution since probabilistic modelling requires large amount of data. In this paper, instead, the information provided by experts based on their experience and engineering knowledge was used to model uncertainty using the evidence theory. In designing the DCR(Dual Combustion Ramjet) engine, the combustion efficiencies, not well understood and little data existing, are assumed to have been provided by experts. And the uncertainties are quantified by Evidence theory. The quantified uncertainties are incorporated into the optimization. The design variables, area of inlet and area of combustor exit, have been found while satisfying reliability margins of thrust and thermal choking. The results show a reasonable design of the engine under the uncertain circumstances.

• The Journal of the Korea institute of electronic communication sciences
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• v.8 no.2
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• pp.285-290
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• 2013

The slotless linear synchronous motor(LSM) has the advantages that the structure of the mover is simple and it can control the trust force ripple by make the magnetic energy in a gap uniform by removing a slot of the primary iron core. Also, the application of the transportation system is becoming expansion because it high efficiency drive is possible and compares with the other LSM as control is more excellent. However, the application of the living field was unsatisfactory. Therefore, in this study, we examined the drive characteristics by the position feedback control for the living field application of the slotless LSM and we prove useful of the controller through load loading and the acceleration changing to get minimization of the speed vibration and stable answer characteristics.

• Journal of the Korean Society of Propulsion Engineers
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• v.22 no.2
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• pp.125-130
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• 2018

The technology development of a high performance upper stage engine for a GEO(GEostationary Orbit) KSLV(Korea Space Launch Vehicle) is undergoing in Korea Aerospace Research Institute. KSLV is composed of an open cycle engine with gas generator, which is for a low orbit launch vehicle. However the future GEO launch vehicle requires a high performance upper stage engine with a high specific impulse. The staged combustion cycle engine is necessary for this mission. In this paper, current progress and future plan for staged combustion cycle engine development is described.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.4
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• pp.447-456
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• 2010

The application of a reliable motion simulator can contribute effectively in the evaluation of the performance of a vehicle platform in the development stage of a small unmanned aerial vehicle (UAV). Therefore, the research on a reliable motion simulator can accelerate the development of UAV and decrease the relevant cost. In this paper, the design factors considered in the preliminary design stage of a 6 degree-of freedom motion simulator are defined and the motion range of the simulator is described on the basis of these design factors. The length, acceleration, and the required thrust of actuators with respect to the motion simulator under development are also predicted. The motion range can be increased and a suitable actuator can be selected and produced by applying these results in the manufacturing process of the motion simulator. Thus, the reliability of the motion simulators can be achieved during the actual design operation of the UAV.