• Journal of the Korean Society of Propulsion Engineers
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• v.10 no.2
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• pp.78-86
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• 2006

This paper presents the performance test result of the 30-ton class turbopump turbine. Test has been conducted using high pressure cold air, The turbine overall performance has been measured for various pressure ratio and rotational speed settings. The nozzle-rotor clearance effect on turbine performance also has been tested for the four kinds of the nozzle-rotor clearance values. We found that turbine efficiency rated 51.1% at its design velocity ratio and pressure ratio of 13.5. We also found that turbine efficiency can be increased by 3.5% for approximately 1mm decrement of the nozzle-rotor clearance from its nominal value.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.11a
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• pp.149-152
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• 2010

It was investigated that effect of the supersonic impulse turbine rotor leading edge thickness which was the part of 75 ton open cycle liquid rocket engine turbopump. The test for turbine was performed that the rotor thickness to pitch ratio was 1.9 and 1.4 to 30 ton turbine. As a result of test, the rotor with lower thickness(1.4) had 1.5% efficiency gain to the higher thickness(1.9) and the pressure ratio with maximum efficiency was increased to the nozzle full expansion point.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.11a
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• pp.786-792
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• 2010

The present study deals with numerical flow analysis to investigate the effect of sweep and lean on the performance characteristics of a partial admission supersonic turbine. The flow analysis was performed for three different angles. The angles of sweep and lean are $5^{\circ}$, $10^{\circ}$, $15^{\circ}$. The results of the flow analysis showed that the efficiency is improved as the sweep angle is increased. However, a sweep angle of $5^{\circ}$ was less effective in comparison with the baseline model. The total pressure loss was reduced as the lean angle is increased, but the total to static efficiency was decreased.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.11a
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• pp.577-580
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• 2010

Coaxial injectors using GCH4/LOx as propellants was designed with shear(gas)/shear(liquid) type and shear(gas)/swirl(liquid) type. Spray characteristics were investigated by cold flow test. Spray patterns of the shear/shear and the shear/swirl type injectors were like a spout of water and hollow cone, respectively. Atomization efficiency of the shear/swirl type injector was better than atomization efficiency of the shear/shear type injector.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2004.03a
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• pp.125-130
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• 2004

Experimental study on combustion characteristics of double swirl coaxial injectors has been conducted for the assessment of critical injector design parameters. A reusable, unielement thrust chamber has been fabricated with a water-cooled copper nozzle. Two principle design parameters, a swirl angle and a recess length, have been investigated through hot firing tests for the understanding of their effects on high pressure combustion. Clearly, both parameters considerably affect the combustion efficiency, dynamics and hydraulic characteristics of an injector. Internal mixing of propellants in a recess region increases combustion efficiency along with the increase of a pressure drop required for flowing the same amount of mass flow rates. It is concluded that pressure buildup due to flame can be released by the increase of LOx flow axial momentum or the reduction of a recess length. Dynamic pressure measurements of the thrust chamber show varied dynamic behaviors depending on injector configurations.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.05a
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• pp.77-80
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• 2010

A series of hydraulic tests of a Lox pump are performed using water at a room temperature. According to the test results, the Lox pump satisfies its design requirement but both the head and the efficiency do not fully follow the conventional similarity rule. The deviation of the head from the rule is assumed to be due to the increased volute loss at high rotational speed. Furthermore, it is found that when the pump rotates with the flow ratio less then the design requirement the leakage flowrate seems to be increased.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.1196-1199
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• 2017

A series-hybrid power system was designed for quad-tilt prop UAV and the characteristics was analysed. The power system consists of a 4.5kW rotary engine-generator and a li-battery as power sources, a power controller manages the overall power and supplies to the vehicle system. The output power of the engine is to be matched with the generator performance considering mechanical driving loss and generating efficiency, and also loss for charging and discharging of the battery energy. It is applied that the constant speed operation of the engine-generator to minimize overall fuel consumption by integrating the generating power and the battery energy, consequentially the battery capacity and characteristics could be important factors for improvement of the system efficiency.

• Journal of the Korean Society of Propulsion Engineers
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• v.24 no.1
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• pp.9-16
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• 2020

A performance evaluation of the 200 N-class GCH₄/LOx small rocket engine was performed through ground hot-firing test. As a result, the combustion pressure and thrust raised with the increase of the oxidizer supply pressure, and thus the specific impulse, characteristic velocity, and their efficiency increased. The characteristic velocity was measured at about 90% performance efficiency. The change of chamber aspect ratio did not affect the performance of the rocket engine in the test condition specified. In addition, uncertainty evaluation was conducted to ensure the reliability of the test results.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2004.10a
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• pp.210-214
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• 2004

This study proposes a design method for blade pitch control mechanism in order to regulate the power and to improve the starting characteristic. This power control unit which is assembled by spring and mass is planing to equip with 1kW class wind turbine system which is developed for low wind speed area like Korea. For the design of this control unit, the proper geometry of the hub was designed and the calculation of the mechanics was carried out. Especially, It is expected that the operational efficiency will be improved because of additional high pitch starting function by using 2 step spring structure.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2004.10a
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• pp.259-264
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• 2004

The critical component of combustor having high combustion efficiency for high performance liquid rocket engine is injector. The results of design and hot firing tests of six sub-scale combustors which have respectively an impinging type injector(1ea.), an bi-propellant swirl closed injector(1ea.), and hi-propellant swirl mixed injector(4ea.) were described in this paper. The combustion test were successfully performed. The combustion efficiency have higher value than predicted value and high frequency combustion instability does not occur.