• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2007.11a
• /
• pp.297-301
• /
• 2007

The blades of supersonic turbines with low aspect ratio are usually designed to have the same cross sectional shape in radial direction. The profile diameter definition of turbines may lead to produce unintended flow passage area variations resulting performance degradation. In this paper, the effects of profile diameter definition on the supersonic impulse turbine performance have been investigated. Computational results of three different profile diameters are compared. It has been found that flow passage area variation can be achieved according to designer's intention when blade profile is defined at rotor tip diameter. Furthermore, the turbine blade profile defined at rotor tip showed better performance than the others.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.14 no.3
• /
• pp.23-29
• /
• 2010

A supersonic nozzle specially is one of the important part in a supersonic turbine usually adapted the impulse type, because the flow acceleration in the turbine theoretically is done only in the nozzle. The present study deals with numerical flow analysis to investigate the effect of nozzle shapes on the performance characteristics of a partial admission supersonic turbine. The flow analysis was performed for four different nozzle shapes. The shapes of the nozzles are circular, square, straight rectangular and bent rectangular nozzles. The results of the flow analysis showed that the aerodynamic loss of turbine is highly affected by the nozzle shapes, and the partial admission loss is also highly depended on nozzle shapes. Specially, bent rectangular nozzle had the best performance among the nozzle shapes

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• v.y2005m4
• /
• pp.349-354
• /
• 2005

In this paper, a small supersonic wind tunnel is designed and built to study the flow characteristics of a supersonic impulse turbine cascade. The flow is visualized by means of a single pass Schlieren system. The supersonic cascade with 2-dimensional supersonic nozzle was tested for various blade leading edge shapes and gaps between the nozzle and cascade. Highly complicated flow patterns including shocks, nozzle-cascade interaction and shock boundary layer interactions are observed.

• Proceedings of the KSME Conference
• /
• 2004.04a
• /
• pp.1732-1737
• /
• 2004

In this paper, a small supersonic wind tunnel is designed and built to study the flow characteristics of a supersonic impulse turbine cascade. The flow is visualized by means of a single pass Schlieren system. The supersonic cascade with 3-dimensional supersonic nozzle was tested over a wide range of nozzle installation angle. Highly complicated flow patterns including shocks, nozzle-cascade interaction and shock boundary layer interactions are observed.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.8 no.4
• /
• pp.1-8
• /
• 2004

In this paper, a small supersonic wind tunnel is designed and built to study the flow characteristics of a supersonic impulse turbine cascade. The flow is visualized by means of a sin91e pass Schlieren system. The supersonic cascade with 3-dimensional supersonic nozzle was tested over a wide range of nozzle installation angle. Highly complicated flow patterns including shocks, nozzle-cascade interaction and shock boundary layer interactions are observed.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2004.03a
• /
• pp.807-812
• /
• 2004

In this paper, a small supersonic wind tunnel was designed and built to study the flow characteristics of a supersonic impulse turbine cascade by experiment. The flow was visualized by means of a single pass Schlieren system. The supersonic cascade with 3-dimensional supersonic nozzle was tested over a wide range of pressure ratio. Highly complicated flow patterns including shocks, nozzle-cascade interaction and shock boundary layer interactions were observed.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2010.11a
• /
• pp.160-163
• /
• 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
• /
• 2010.11a
• /
• pp.43-48
• /
• 2010

Present study was conducted numerical analysis for velocity compound supersonic impulse turbine with the rotor overlaps, and the performance characteristics were analyzed through the numerical results. Tip overlap was more effective than hub overlap through the analysis. a case, overlap applied the hub and tip of the rotor, has the largest improvement for the turbine performance in parametric study cases. In case of overlap for the 2nd stage rotor, however, improvement of the turbine performance was not visibly large. Because, power generated in the 2nd stage was 22~23% of whole generated turbine power.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2008.11a
• /
• pp.117-121
• /
• 2008

The effect of tip clearance on the performance of a supersonic impulse turbine was investigated experimentally. Test was performed using high pressure air in wide ranges of pressure ratio and rotational speeds. Test revealed that efficiency gradient of the subject turbine at a reference test point was a very low value of 0.05. Turbine efficiency was varied non-linearly with respect to tip clearance. It has been found that efficiency gradient is proportional to the cube of rotational speed at a fixed turbine pressure ratio. It also has been found that efficiency gradient shows its minimum at a reference test pressure ratio irrespective of rotational speeds.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.12 no.4
• /
• pp.48-55
• /
• 2008

In this paper, numerical analysis of the surface gas temperature on turbine blades has been performed to investigate the temperature profiles characteristics of a partial admission supersonic turbine driven by high temperature and pressure gas of pyro-starter with two different types of turbine blade edge shape. In order to examine the surface gas temperature on turbine blades at initial starting, computations tlave been carried out at several turbine rotational speeds in the range of $0{\sim}10,000$ rpm for each type of turbine edge shape. "Sharp" edge and "Round" edge types were taken as the turbine edge shape factor. As turbine rotational speed increased, the average temperature of turbine blades was further decreased. It was also found that the surface temperature of turbine blades with a sharp edge was lower than round-type edge turbine blades.