• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.30 no.4
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• pp.99-105
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• 2002

The performance test of an axial-type turbine is carried out with various axial gap distances between the stator and rotor. The turbine is operated at the low pressure and speed, and the degree of reaction is 0.373 at the mean radius. The axial-type turbine consists of ons-stage and 3-dimensional blades. The chord length of rotor is 28.2mm and mean diameter of turbine is 257.56mm. The power of turbo-blower for input power is 30kW and mass flow rate is $340m^3$/min at 290mmAq static-pressure. The RPM and output power are controlled by a dynamometer connected directly to the turbine shaft. The axial gap distances are changed from a quarter to three times of stator axial chord length, and performance curves are obtained with 9 different axial gaps. The efficiency varies about 8% of its peak value due to the variation of axial gap on the same non-dimensional mass flow rate and RPM, and experimental results show that the optimum axial gap is 1.6-1.9Cx.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.12
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• pp.76-82
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• 2005

An experimental study on an axial-type micro turbine which consists of maximum 6 stages is conducted to measure aerodynamic characteristics on each stage. This turbine has a 2.0 flow coefficient, 3.25 loading coefficient and 25.8mm mean diameter. The solidity of stators and rotors is within a 0.67~0.75, and the off-design performance is measured by changing the load after adjusting the mass flowrate and the total pressure to constant at inlet. A maximum specific output power of 2kW/kg/sec is obtained in one stage, but the increment of the specific output power with increasing stages is alleviated. In case of torque, the increment of the torque maintains to constant at low RPM region, but its increment become dull at high RPM region. The efficiency of the micro turbine becomes low because the tip gap effect is great due to the small blade, but it could be improved by increasing the stages.

• Journal of the Korean Society of Propulsion Engineers
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• v.5 no.2
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• pp.24-31
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• 2001

An axial-type turbine design technology is developed. In order to design one-stage turbine, the preliminary design method is applied, and then design parameters are chosen after analyzing gas properties within the turbine passage using the streamline curvature method. Stator blade is designed using C4 profile, and rotor blade is designed using shape parameters. Stator is manufactured as an integral type and rotor is manufactured to be disassembled from the disc for changing blade incidence angle. The output power from the rotor is measured with various RPM and input power. Experimental results show that the maximum efficiency of turbine rotor is obtained on the design point, and the output power is proportionally decreased with the negative incidence angle even the test turbine is a reaction turbine. The efficiency of turbine rotor is decreased to 5% by $7.5^{\cire}$ negative incidence angle from the designed value.

• Journal of the Korean Society of Propulsion Engineers
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• v.11 no.4
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• pp.10-18
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• 2007

A tested micro axial-type turbine consists of two stages and its mean radius of rotor flow passage is 8.4 mm. This turbine could be applied to a driver of micro power system, and its rotational speed in the unloaded state reaches to 100,000 RPM. The performance of this system is sensitive depending on the blade angles of the rotor and stator because it is operated in a low partial admission rate, so a performance test is conducted through measuring the specific output power and the net specific output torque with various blade angles on the nozzle, stator and rotor. The experimental results show that the net specific output torque is varied by 15% by changing the rotor blade angle, and the optimal incidence angle is about $10.3^{\circ}$.

• Journal of the Korean Society of Propulsion Engineers
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• v.12 no.6
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• pp.21-29
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• 2008

Performance characteristics on a partially admitted small axial-type turbine are experimentally studied with changing design parameters, such as exit flow angles at the nozzle and solidities at the rotor. The tested turbine consists of a single-stage and its mean radius is 35 mm. In this experiment, three different solidities and four different nozzle flow angles are applied to find the optimal design parameter. For a comparison of the turbine performance, the net specific output powers are evaluated. For a 3.4% partial admission rate, the best performance is obtained when the rotor solidity is at 2.18, which is increased to 74% compared to the solidity at full admission.

• Journal of the Korean Society of Propulsion Engineers
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• v.9 no.3
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• pp.10-17
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• 2005

A performance prediction model is developed for partially admitted axial-type turbines. Losses generated within the turbine are classified to the windage loss, expansion loss and mixing loss. The developed loss model is compared with an experimental result. The results predicted with the developed model agree well with the experimental results than those predicted with several other models because this model considers three different kinds of losses. Moreover, this model predicts well the performance even the partial admission is changed. So, this model could be applied to predict the performance of partially admitted axial turbine and it has a high accurate performance.

• Journal of Power System Engineering
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• v.5 no.3
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• pp.38-47
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• 2001

One stage axial type turbine is designed by mean-line analysis, streamline curvature method and blade design method using shape parameters. Tip and hub diameter of the turbine are 300mm and 206.4mm, respectively. The rotating speed is 1800RPM, and the output power is 1.4kW. The flow coefficient is 1.68 and the reaction factor at mean-line is 0.373. The number of stator and rotor of the turbine are 31 and 41, respectively. Mach number of stator exit flow near hub is 0.164. A test rig is developed for performance test to validate a developed design method. The experimental result shows that the maximum efficiency is obtained on the design point.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.36 no.9
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• pp.898-906
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• 2008

A tested turbine consists of two stages, and an axial-type and a radial-type turbine are applied to the first and second stage, respectively. The mean diameter of the axial-type turbine rotor is 70 mm, and the outer diameter of the radial-type turbine is 68mm at the inlet. In this experiment, an axial-type turbine, two different radial-type turbines, and three different nozzle flow angles are applied to find the optimal design parameters. To compare the turbine performance, the net specific output torque is evaluated. The test results show that the nozzle flow angle on the first stage is a more important parameter than other design parameters for partially admitted small turbines to obtain high operating torque. For a 3.4% partial admission rate, the net specific output torque is increased by 13% with the addition of a radial-type rotor to the second stage when the turbine operates at $75^{\circ}$ nozzle flow angle.

• 유체기계공업학회:학술대회논문집
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• 1997.02a
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• pp.25-36
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• 1997

• Proceedings of the KSME Conference
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• 2002.08a
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• pp.541-544
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• 2002

The turbine performance test of an axial-type turbine is carried out with various axial gap distances between the stator and rotor. The turbine is operated at the low pressure and speed, and the degree of reaction is 0.373 at the mean radius. The axial-type turbine consists of ons-stage and 3-dimensional blades. The chord length of rotor is 28.2mm and mean diameter of turbine is 257.56mm. The power of turbo-blower for input power is 30kW and mass flow rate is $340m^3/min\;at\;290mmAq$ static-pressure. The RPM and output power are controlled by a dynamometer connected directly to the turbine shaft. The axial gap distances are changed from a quarter to two times of stator axial chord length, and performance curves are obtained with 7 different axial gaps. The efficiency is dropped about $5{\%}$ of its highest value due to the variation of axial gap on the same non-dimensional mass flow rate and RPM, and experimental results show that the optimum axial gap is 1.0-1.5Cx.