• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.11a
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• pp.569-572
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• 2010

In order to study the performance characteristics of the thrust vector nozzle, the test facility and instrumentation system were designed. In this system, axial thrust, moment, exhaust gas velocity and pressure will be measured by using the scale down experimental model devices. The test facility are composed of high pressure air storage system, flow measuring and control system, test nozzle and thrust measurement system.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.10
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• pp.1473-1478
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• 2014

This paper deals with design and thrust force measurement of EMS type LSM for propulsion of the high-speed maglev train. The load of maglev train is calculated, and the design equations of the LSM are presented, and the LSM which is suitable for the operation of short-distance test track is designed. In addition, the finite element analysis is performed to confirm the back-EMF and thrust force characteristics of the LSM designed model. A short length LSM prototype model is manufactured. Finally, the thrust force of the LSM is measured by the method applying dc current to the stator winding instead of three-phase ac current. And the validity of the design and analysis is verified by this measurement.

• Transactions of the Korean Society of Automotive Engineers
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• v.24 no.6
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• pp.642-648
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• 2016

This paper deals with an analytical and experimental investigation to predict the axial thrust load that results from turbocharger operating conditions. The Axial forces acting on the turbocharger thrust bearing are caused by the unbalance between turbine wheel gas forces and compressor wheel air forces. It has a great influence on the friction losses, which reduces the efficiency and performance of high-speed turbocharger. This paper presents the calculation procedure for the axial thrust forces under operating conditions in a turbocharger. The first step is to determine the relationship between thrust forces and strains by experimental and numerical methods. The analysis results were verified by measuring the strains on a thrust bearing with the specially designed test device. And then, the operating strains and temperatures were measured to inversely calculate the thrust strains which were compensated the thermal effects. Therefore it's possible to calculate the magnitudes of the thrust forces under operating turbocharger by comparing the regenerated strains with the rig test results. It will possible to optimize the design of a thrust bearing for reducing the mechanical friction losses using the results.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.805-806
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• 2011

Thermal conductivities of a Ni-Cr coating applied for the protection of a thrust chamber operating under the condition of high pressure and high temperature were measured. Results showed that the data used in heat transfer calculation has a 20~25% margin compared with data measured.

• Tribology and Lubricants
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• v.13 no.4
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• pp.47-52
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• 1997

Friction torques, electrical contact resistances and bearing temperatures were measured on high speed angular contact ball beatings for the spindle of machine tools. The test bearings ran with oil-air lubrication at the thrust loads from 320 N to 1920 N and at the rotational speed of up to 12000 rpm. Electrical contact resistances between balls and races were measured to evaluate the formation of the lubricant film in the contact area. The test results with sufficient lubrication showed that the variations of friction torques were sensitive to the thrust loads and the rotational speeds, and that the friction torques were higher than those with insufficient lubrication. With insufficient lubrication and high thrust loads, the collapse of the lubricant film was detected even at a high rotational speed. It was concluded that these high speed beatings to run in condition of fluid lubrication should require monitoring not only the temperature increase of the bearing but also the lubricant film formation in contact areas resulting from the change in the applied load and the lubricant amount.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.5
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• pp.413-422
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• 2012

The ducted fan for a small UAV propulsion can reconnoiter and observe in a town and a small area, it has better thrust efficiency and a long endurance than propeller. Thrust characteristics of hover and for ward flight condition for the ducted fan UAV is important issue to improve a endurance. The unsteady 3-dimensional flow fields of the ducted fan UAV is essential to stable flight. In this paper, to verify the design results of the ducted fan and to investigate a stable aeronautical characteristic, the thrust performance and the unsteady 3-dimensional flow fields are measured. Thrust characteristics for the hovering and the forward flight conditions are measured by the 6-components balance system in the subsonic wind tunnel. The unsteady 3-dimensional flow fields are analyzed by using a stationary $45^{\circ}$ slanted hot-wire technique. The swirl velocity is almost removed behind the stator blades. Therefore, the thrust performance of the ducted fan is improved and the flight stability is maintained.

• Journal of the Korean Society of Propulsion Engineers
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• v.5 no.2
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• pp.16-23
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• 2001

For liquid rocket engine test, one of most important design parameters to be measured is thrust. However, not like solid rocket motor, a liquid rocket engine is attached to the propellant feed system, control valve and many other safety systems. Without considering these effects, thrust data measured from firing test is not reliable and sometimes almost meaningless. In this research, new thrust measurement system, which includes all these side effects, was designed and fabricated.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.46 no.3
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• pp.189-196
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• 2018

Propeller performance measurement system for high altitude UAV was designed and applied to the wind tunnel test for 2 propeller models with a diameter around 1 m. Mechanical power of the propeller was directly measured by using the torque sensor installed on the rotating axis. The thrust of whole operation body including the propeller was measured by thrust road cell. The guide rail system was suggested to reduce the weight influence of operation body on the thrust road cell. The influence of each measured variables on the aerodynamic coefficients was studied with the repeatability and uncertainty analysis. This analysis result shows that the accuracies of the road cell and the wind velocity were major factors for the thrust coefficient. Propeller performance with typical RPM was measured with various wind speeds and the test results was summarized by performance coefficients for 5 different RPM.

• Aerospace Engineering and Technology
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• v.9 no.2
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• pp.8-13
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• 2010

An effective control of the axial thrust of a turbopump is one of the critical issues for obtaining its operational stability. Axial thrusts of the fuel pump for the 75-ton class rocket engine under development were measured with water as a test propellant at a room temperature. According to the test results, the axial thrust of the fuel pump seemed to satisfy the axial force condition of its bearing. Also, the thrust was increased as a whole when the flowrate of the pump was decreased. Furthermore it was found that the thrust and the leakage flowate were modified when the gaps between the floating ring seals and the impeller were changed.

• International Journal of Aeronautical and Space Sciences
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• v.13 no.3
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• pp.317-322
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• 2012

The low speed aerodynamic characteristics for a modified sonic arc airfoil which is designed by using the nose shape function of sonic arc, the shape function of NACA four-digit wing sections, and Maple are experimentally investigated. The small rotor blades of a modified sonic arc and NACA0012 airfoil are precisely fabricated with a commercially available light aluminum(Al 6061-T6) and are spin tested over a low speed range (3000rpm-5000rpm). In a consuming power comparison, the consuming powers of NACA0012 are higher than that of modified sonic arcs at each pitch angle. The measured rotor thrust for each pitch angle is used to estimate the rotor thrust coefficient according to momentum theory in the hover state. The value of thrust coefficients for both two airfoils at each pitch angle show almost constant values over the low Mach number range. However, the rotor thrust coefficient of NACA0012 is higher than that of the modified sonic arc at each pitch angle. In conclusion, the aerodynamic performance of NACA0012 is better than that of modified sonic arcs in the low speed regime. This test model will provide a convenient platform for improving the aerodynamic performance of small scale airfoils and for performing design optimization studies.