• Journal of the Korean Society of Propulsion Engineers
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• v.7 no.3
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• pp.38-44
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• 2003

In this study, a performance model of the smart UAV propulsion system with ducts, tip jets and variable main nozzle, which has flight capability of the rotary wing mode for the take-off/landing and low speed forward flight as well as the fixed wing mode for high speed forward flight, has been newly developed With the proposed model, steady-state performance analysis was performed at various flight modes such as rotary wing mode, fixed wing mode, compound ing mode and altitude as well as at flight speed conditions. In investigation of performance analysis. it was noted that the operational capability of the propulsion system was limited due to the duct losses depending on each flight mode, and the limitation with the altitude variation case had much greater than that with the flight speed variation case.

• The KSFM Journal of Fluid Machinery
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• v.6 no.2 s.19
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• pp.41-46
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• 2003

The hydraulic design optimization and performance analysis of mixed-flow pumps for waterjet marine vehicle propulsion has been carried out using mean streamline analysis and three-dimensional computational fluid dynamics (CFD) code. In the present study, the conceptual design optimization has been formulated with a non-linear objective function to minimize the fluid dynamic losses, and then the commercial CFD code was incorporated to allow for detailed flow dynamic phenomena in the pump system. Newly designed mixed-flow model pump has been tested in the laboratory. Predicted performance curves by the CFD code agree very well with experimental data for a newly designed mixed-flow pump over the normal operating conditions. The design and prediction method presented herein can be used efficiently as a unified hydraulic design process of mired-flow pumps for waterjet marine vehicle propulsion.

• Proceedings of the KSR Conference
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• 1998.05a
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• pp.349-358
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• 1998

This study was carried out about the design and the performance study of propulsion system for Korean High Speed Train of maximum operating speed of 350km/h. The propulsion system was studied to two parts the formation of power transmission and the performance of traction system base on Korean-TGV. For maximum operating speed of 350km/h at Seoul-Pusan high speed line, the power of train should be have the remaining acceleration of 0.058m/s/s and the slopeability of 6%o. This performance study of propulsion system would be continued for defining of adhesion factor, friction factor and aerodynamic factor assumed to analysis and simulation.

• Korean Journal of Applied Biomechanics
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• v.17 no.3
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• pp.165-172
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• 2007

The purpose of this study was to examine the effects of the result of hardship performance of the propulsion speed on the flying carmel spins during a Figure Skating. The subjects were five the korea national representative players. Kinematic variables were analyzed 5frame of the excursion phase by the three-dimensional motion analysis system(60Hz). The obtained conclusion were as follows: In this study, during the propulsion classify two groups as "type I" the acceleration patterns S3, S4 and "type II" the uniform velocity group S1, S2, S5. The results of percentage comparative analysis between type I and type II can be summarized as below: the height of jump(24%), the height of COM(25%), the maximum speed of Roundhouse Kick(21%), the judging technical score(18%), the flight time(13%), the velocity of spins(4%), the distance of flight(-6%) Analysis of the results on performance variables, the velocity pattern of the type I showed comparatively excellence than that of type II.

• Proceedings of the KWS Conference
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• v.43
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• pp.213-215
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• 2004

Water jet propulsion system has high efficiency on middle to high speed, and it provides better safety than conventional screw propeller because it has not projected propeller and rudder. So many leisure boat and high-speed ferries use this propulsion system. We developed water-jet propulsion unit for small planning boat, and launched that in the boat, after that we tested water-jet unit in the lake. As a result, we certify heat dissipation at the bearing housing and reverse duct's shape for neutral position are important at the design, and alignment water-jet unit and keel line are important at the launching, and ship's resistance performance and jet's propulsion performance also are needed to consideration.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.04a
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• pp.27-30
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• 2011

For the successful development of korean lunar lander, the ground test is required in order to verify performance of propulsion system, attitude control system, performance of landing device and etc. In order to develop the lunar lander ground test model, development of large size thruster and pressure regulated propulsion system is now in progress. In this paper, the results of 200N class monopropellant thruster development and propulsion system design will be presented.

• Journal of computational fluids engineering
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• v.15 no.1
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• pp.81-87
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• 2010

In this study, we conducted resistance and propulsion performance test of ship composed of the Resistance Test, Propeller Open Water Test and Self Propulsion Test using the CFD(Computational Fluid Dynamics). We used commercial RANS(Reynolds Averaged Navier Stokes equation) solver, as a calculating tool. The unstructured grids were used in a bow and stern of ship, having complex shape, for a convenience of generating grids, and the structured grids were adopted in a central hull and rest of hull having a relatively simple shape which is called hybrid grid method. In addition, The sliding mesh method was adopted to rotate a propeller directly in the Propeller Open Water and Self Propulsion Test. The Resistance Test and Self Propulsion Test were calculated using Volume of Fluid (VOF) model and considering a free surface. And all The three cases were applied realizable k-epsilon model as the turbulence model. The results of calculations were verified for the suitability of calculations by comparing MOERI's EFD results.

• Journal of the Korean Society of Propulsion Engineers
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• v.24 no.2
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• pp.61-72
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• 2020

Performance characteristics of propulsion systems applied to UAVs that under development or completed in foreign countries were analyzed. In this study, aircraft mission and performance characteristics of ten UAVs were reviewed and compared with current available civil and military aircraft. Also performance characteristics of UAVs propulsion systems were summarized and engine design parameters were analyzed. Thrust, SFC and design parameters such as pressure ratio and bypass ratio of UAV propulsion system were compared with the current existing civil and military aircraft engines. From this study, the design parameters of the propulsion system applied to the UAV were well understood.

• Journal of the Korean Society of Propulsion Engineers
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• v.23 no.2
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• pp.27-37
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• 2019

The shell and tube heat exchangers installed in the propulsion system test complex (PSTC) at the Naro Space Center heats cryogenic helium to 500 K with a heat transfer oil. As the experimental helium outlet temperature was lower than expected (less than 100 K), the boundary layer effect of the heat transfer oil is predicted to be the cause of the performance deterioration. A computational fluid dynamics (CFD) analysis was performed to verify where the boundary layer effect exists; however, the boundary layer effect has no significant impact on the performance of the heat exchanger. An alternative method to improve the performance of the heat exchanger by changing the heat transfer oil has been discussed in this paper. The low viscosity and high thermal conductivity at high temperature (~500 K) of heat transfer oil at the shell-side are required to improve the thermal performance of the heat exchanger. The experimental performance of the heat exchanger, used to exchange heat between the cryogenic helium and hot heat transfer oil at the PSTC are summarized in this paper.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.11a
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• pp.371-377
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• 2009

The propulsion system of turboprop has been rarely used in the large aircraft due to the limitation of the maximum velocity of the propeller, the power limitation by the reduction gear, etc. Recently, the demand on turboprop aircraft continues to increase because of economical efficiency and environmental factors. In this paper, turboprop propulsion system which is composed of a Pratt & Whitney 127F turboprop engine and a Hamilton Standard 568F propeller was modeled by using the Gasturb11 software. The result of the performance analysis on this propulsion system model showed that the propulsion system model was evaluated to have been successfully builded.