• The KSFM Journal of Fluid Machinery
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• v.3 no.4 s.9
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• pp.38-43
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• 2000

Recently, KARI(Korea Aerospace Research Institute, Korea) and CIAM(Central Institute of Aviation Motors, Russia) have made an effort in developing a centrifugal compressor for a small gas turbine engine as part of a collaboration program. This compressor has been designed as a sub-component for an axial-centrifugal compression system for a small turbo-shaft engine aiming adiabatic efficiency higher than 0.81. The geometrical design requirement imposes restrictions to have high inlet hub-to-tip ratio and inlet swirl flow. In this study, the compressor has been designed using the generalized experimental data established from those compressors having pressure ratio of 3.7 to 5. From this generalized empirical correlation, desirable values of design parameters could be obtained. Subsequently, quasi-3D and 3D viscous flow analyses have been performed to ensure the adopted methodology. It is expected that the centrifugal compressor provides total pressure ratio of 4.89, corrected mass flow-rate of 1.64kg/sec, and adiabatic efficiency of 0.815 with inlet hub-to-tip ratio of 0.641. These relatively high total pressure ratio and inlet hub-to-tip ratio are the main distinctive features in this design. Besides, one of the main features of this centrifugal compressor is the adoption of a double-row bladed diffuser to effectively decelerate the transonic flow leaving the impeller. The compressor has been manufactured and will be tested in the near future.

• Journal of the Korean Society of Propulsion Engineers
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• v.18 no.6
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• pp.42-49
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• 2014

Test device using virtual engine simulator can help reduce the number of engine tests through tests similar to the actual engine tests and repeat the test under the same condition, and thus reduce the engine maintenance and operating costs. Also, as it is possible to easily implement extreme conditions in which it is hard to conduct actual tests, it can prevent engine damages that may happen during the actual engine test under such conditions. In this study, an upgraded small jet engine performance test device was developed that can conduct both real and virtual engine test by applying real-time engine model to the existing micro jet engine performance test device that was previously developed by authors. This newly developed multi-purpose small jet engine performance test device is expected to be used for various educational and research purposes.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.12
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• pp.3148-3165
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• 1993

A cascade wind tunnel test for a turbine nozzle, which was designed for a small turbo jet engine in a previous study, has been conducted to evaluate its aerodynamic performance and losses. The large-scale blades were based on the mid-span profile of the nozzle. Oil film flow structure, and then 3-dimensional velocity components were measured in the flow passage with a 5-hold pressure probe, in addition to turbulent intensities at mid-span of cascade exit using a hot-wire anemometer. From this study, 3-dimensional growth of horseshoe and passage vortices in the downstream direction was clearly understood with near-wall flow phenomena. In addition, secondary flow and losses associated with the blade configuration were obtained in detail.

• Journal of the Korean Society of Propulsion Engineers
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• v.15 no.2
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• pp.23-28
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• 2011

The engine ground and altitude tests were carried out to investigate the effect of jet fuel alteration on the performance of a small turbojet engine. JP-S was supplied 8% higher than JP-8 by fuel metering system at the same command. The employment of JP-S showed the similar starting characteristic to that of JP-8, however, difference in the ignition time and acceleration rate of engine speed due to the difference of fuel flow rate by fuel metering system was observed. In spite of jet fuel alteration, the test results yield the similar steady-state engine performance in net thrust, air flow, exhaust gas temperature, etc. On the other hand, the fuel consumption of JP-S increased by 5 % compared with that of JP-8. In point of specific fuel consumption (SFC), SFC of JP-S was approximately 1.1~2.6 %, 5 % higher than that of JP-8 in ground and altitude tests respectively at the same thrust.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.11a
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• pp.410-415
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• 2010

The engine ground and altitude tests were carried out to investigate the effect of jet fuel alteration on the performance of a small turbojet engine. JP-S was supplied 8% higher than JP-8 by fuel metering system at the same command. The employment of JP-S showed the similar starting characteristic to that of JP-8, however, difference in the ignition time and acceleration rate of engine speed due to the difference of fuel flow rate by fuel metering system was observed. In spite of jet fuel alteration, the test results yield the similar Steady-State engine performance in Net thrust, Air flow, Exhaust Gas Temperature, etc. On the other hand, the Fuel consumption of JP-S increased by 5 % compared with that of JP-8. In point of Specific Fuel Consumption (SFC), SFC of JP-S was approximately 1.1~2.6 %, 5 % higher than that of JP-8 in ground and altitude tests respectively at the same thrust.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.864-870
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• 2017

The propellants are burned in the pre-burner of the staged combustion cycle engine, and the resulting hot gas drives the turbine, and the turbine operates the turbo pump. The burned gas passing through the turbo pump is supplied to the combustor at high temperature and high pressure, where the gas is supplied in an excess of fuel or an excess of oxidant depending on the amount of fuel or oxidant. When the cycle works at oxidizer-rich staged combustion, its metal pipe can ignite or explode by the impact of even small particles. In this study, we develop the powder combinations for anti-oxidation coating through the analysis of other coating materials and establish the coating process.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.8
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• pp.1007-1013
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• 2013

This study aims to analyze the aerodynamics when the geometry of the turbine rotor is modified. The turbine used in this study is a small engine used in the APU of a helicopter. It is difficult to improve the performance of small engines owing to the structural weakness of the blade tip. Therefore, the improvement of the hub geometry is investigated in many ways. The working fluid of a turbine is a high-temperature and high-pressure gas. The heat transfer rate of the turbine surface should be considered to avoid the destruction of blade owing to the heat load. The SST turbulence model gives an excellent prediction of the aerodynamic behavior and heat transfer characteristics when the numerical simulations are compared with the experimental results. In conclusion, the aerodynamic efficiency is improved when a bulbous design is applied to the leading edge near the hub. The endwall loss is reduced by 15%.

• Tribology and Lubricants
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• v.13 no.1
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• pp.76-81
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• 1997

The lubrication characteristics of high-speed roller bearings at oil-starvation have been investigated empirically using the bearings employed in small industrial gas turbine engines. Testing was done by simulating the oil-starvation conditions in engines, such as stopping the oil-supply to the bearing during normal operating, starting without oil-supply at atmospheric temperature, and accelerating with oil-supply at atmospheric temperature. During testing, the temperature of bearing, the power consumption, and the rotating resistance of the bearing were measured. From this study, on the contrary to the ball bearing, it was found that the resistance of the bearing was higher at the regime of without oil-supply than that at the regime of with oil-supply, despite less power consumption.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.05a
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• pp.514-519
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• 2003

The aircraft engine is usually supported by rolling element bearings and has a small damping rate, which is vol y sensitive to external force. The high-performance requirement of the rotors leads to complex assembly designs and are more flexible. Squeeze film dampers (SFDs) are introduced to provide damping while crossing the critical speeds and stability to the rotor s :stem. Hence, the focus of the present investigation is on the decision of an optimal size of the flexible rotor system supported by the squeeze film dampers to minimize the maximum transmitted load and unbalance response over a range operating speeds. The enhanced genetic algorithm (EGA), which was developed by authors, is used in the optimization process. This algorithm is based on the synthesis of a modified genetic algorithm and simplex method. The results show significant benefits in using EGA when compared with nonlinear programming (NLP).

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2004.10a
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• pp.36-40
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• 2004

Experimental and numerical studies are carried out for inner flow of small gas turbine engine combustor at normal operating altitude and velocity. First of all inner flow and combustion phenomenon without a load is analyzed for understanding with various back pressure condition due to flight mode of smart UAV.