• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.37 no.9
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• pp.889-898
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• 2009

A mixed-type turbine was adopted and the rotor outer diameter was 108 mm. Turbine rotors were designed to the axial-type blade because the turbine operated at a low partial admission rate of 1.7-2.0% with two stages. Performance characteristics were studied when the spouting from the nozzle was toward radially inward or outward direction. Additionally, the effect at each stage of the rotor was measured. For comparing with each turbine performance, properties were measured based on various rotational speeds. Measured net specific torque was used to compare with the turbine system performance. On the mixed-type turbine, better performance was obtained when the operating air spouted toward radially inward direction. The specific torque was increased by 7.8% from using the second stage although its effect depended on the rotational speed.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.11a
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• pp.160-163
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• 2010

We performed three-dimensional CFD analysis to investigate the effect of the nozzle-rotor axial gap of a partial admission supersonic turbine on the stage performance and the flow field. The computations are conducted for five axial gaps using flow analysis program, $FLUENT^{TM}$. The results show that the axial gap between nozzle and rotor give the effect on the mass flow rates of tip leakage and the flow angle at the rotor outlet.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• v.y2005m4
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• pp.128-133
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• 2005

In this study, performance design programs for components of a turbopump unit (TPU) in a Liquid Rocket Engine (LRE), that has non-cryogenic centrifugal pumps and 1-stage impulse turbine with partial admission nozzle, were developed. The programs were integrated in a TPU module by balancing the mass flow rate for pump-turbine power, and the module was inserted into the LRE system conceptual design program. The fundamental design conditions, satisfying LRE system requirements and minimum mass flow rate condition of gasgenerator, were found and compared with data from a Russian liquid rocket engine.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2005.11a
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• pp.34-39
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• 2005

In this study, 3-D nozzle shape and the shape of nozzle at exit plane were adopted as design parameter of 3-D supersonic nozzle and numerical analyses for these parameters have been performed to investigate the flow and performance characteristics for design parameters of the turbine. Firstly, comparing results for nozzle shape, rectangular nozzle had less total pressure loss occurred in axial gap and more power by 1.5% than circular nozzle did. Next, comparing the results for the shape of nozzle at exit plane, it is found that the performance of partial admission turbine was largely depended upon the gap between nozzle wall at exit plane and the hub / tip of rotor blade and the length between nozzles.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2004.03a
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• pp.839-847
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• 2004

In this study, the flow characteristics within supersonic cascades are numerically investigated by using Fine Turbo, a commercial CFD code. Cascade flows are computed for three different inlet conditions. : a uniform supersonic inlet condition, a linear nozzle and a converging-diverging nozzle located in front of cascades. The effect of inlet conditions is compared and flow characteristics including shock patterns and shock-boundary layer interaction are analyzed. Also the effect of design parameters such as pitch-chord ratio, blade angle and blade surface curvature on the flow within supersonic cascades are studied.

• Journal of the Korean Society of Propulsion Engineers
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• v.14 no.3
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• pp.30-38
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• 2010

Experiments were performed to investigate the flow characteristics of a partial admission supersonic turbine depending on the relative positions of nozzle and cascade. The flow was visualized by a Schlieren system. The static pressures at the turbine cascade inlet, passage and outlet were measured by pressure transducers. Highly complicated flow patterns including shocks, nozzle-cascade interaction and shock boundary layer interactions of the supersonic turbine were observed by the experiments. And the flow characteristics in the supersonic turbine as the relative positions were observed.

• International Journal of Aeronautical and Space Sciences
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• v.6 no.1
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• pp.1-7
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• 2005

The inlet boundary condition of computations about the supersonic turbine flow is commonly applied as far-field inlet boundary condition with specified velocity. However, the inflow condition of supersonic turbine is sometimes affected by the shocks or expansion waves propagated from leading edges of blade. These shocks and expansion waves alter the inlet boundary condition. In this case, the inlet boundary condition can not be specified Therefore, in this paper, numerical analyses for three different inlet conditions - fa-field inlet boundary condition, inlet boundary condition with a linear nozzle and inlet boundary condition with a converging-diverging nozzle - have been performed and compared with experimental results to solve the problem. It is found that the inlet condition with a linear nozzle or a converging-diverging nozzle can prevent changing of inlet boundary condition, and thus predict more accurately the supersonic flow within turbine cascade than a far-field inlet boundary condition does.

• Journal of Aerospace System Engineering
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• v.11 no.1
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• pp.8-13
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• 2017

This study was performed to evaluate the turbine performance of a turbopump in the third stage engine of the Korea Space Launch Vehicle-II. The turbine is a supersonic impulse type with a single rotor. One nozzle is for starting and four remaining nozzles are for steady operation. A similarity test was carried out in the high air test facilities at the Korea Aerospace Research Institute. Test results showed that turbine efficiency changed much more from rotational speed variations than by pressure ratio variations. These results showed characteristics similar to other supersonic impulse turbines.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.830-834
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• 2011

In this study, we performed three-dimensional CFD analysis to investigate the effect of the rotor blade sweep of a partial admission supersonic turbine on the stage performance and the flow field. The computations are conducted for three different sweep cases, No sweep(NSW), Backward sweep(BSW), and Forward sweep(FSW), using flow analysis program, $FLUENT^{TM}$ 6.3 Parallel. The results show that BSW model give the effect on the reducing of mass flow rates of tip leakage and the increasing of t-to-s efficiency.

• 유체기계공업학회:학술대회논문집
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• 2006.08a
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• pp.157-160
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• 2006

A turbo-expander is developed for the regeneration in the expansion process. The turbo-expander operates in the partial admission and supersonic flow, and an axial-type single stage turbine is applied to the turbo-expander. Its outer diameter is 82mm and the operating gas is R134a. A 15kW reciprocating compressor is applied in this experiment and the turbo-expander is installed in the expansion process instead of the commonly using expansion valve. Two supersonic nozzles are applied for the expansion process. The high speed of R 134a after passing the supersonic nozzles gives the impulse force to the turbo-expander and some powers are generated on this process. A generator is installed at the end of the turbo-expander shaft. The generating output power from the turbo-expander is controlled by the power controller. Pressures and temperatures are measured on the lines for the performance investigation. More than 600W/(kg/sec) are generated in this experiment.