• 한국유체기계학회 논문집
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• 제4권4호
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• pp.28-36
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• 2001

Performance analysis is conducted on an axial-type turbine which is used for fire extinction by injecting water or steam into the turbine. Loss models developed by Hacker and Okapuu are applied for predicting the performance of turbine. Pressure loss generated through a turbine is converted to the thermal efficiency, and thermal and gas properties are calculated within a turbine passage. Total-to-total efficiency, total-to-static efficiency, static temperature at the exit of turbine, output power, flow coefficient, blade loading coefficient, and expansion ratio are predicted with changing the amount of injected steam and the rotational speed. The 74 kW class gas turbine developed at KIMM is chosen for performance analysis. The 74 kW class turbine consists of 1 stage like a current developing gas turbine for fire extinction. Water or steam is injected at the end of combustor, and results show that efficiency and output power are dependent on the temperature of injected water or steam and the static temperature at the exit is decreased.

• 대한기계학회논문집B
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• 제26권9호
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• pp.1292-1301
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• 2002

An experimental study of turbine performance is conducted with various incidence angles on a rotating turbine rotor. 5 different incidence angles are applied from -17$^{\circ}$to 13$^{\circ}$with 7.5$^{\circ}$gaps. In order to precisely set up the incidence angles at the rotor inlet, 5 turbine discs are manufactured with the different fir tree section. Total-to-total efficiencies are obtained on the several off-design points with considering the exit total pressure, which is meas fred at 12 locations between the hub and casing using a pressure rake. The degree of reaction is 0.373 at the mean radius, and Reynolds number based on the rotor chord is 0.86$\times$10$^{5}$ at the turbine inlet on the design point experiment. The experiment on a single-stage turbine is conducted at the low-pressure and low-speed state, but it is sufficient to consider the blade loading effect due to the rotating apparatus even though the total pressure loss at the exit is increased proportionally to the turbine output power. The experimental results recommend 6$^{\circ}$as an optimum incidence angle on the turbine blade design. The total-to-total efficiency is steeply decreased when the incidence angle is over $\pm$9$^{\circ}$ from the optimum incidence angle. In the range of less than -10$^{\circ}$incidence angle, 7.5$^{\circ}$ reduction of incidence angle generates 15% decrease of total-to-total efficiency. This result is obtained on the same rotor blade by changing only the rotational speed to minimize the effect of profile and secondary flow loss in the passage. Experimental results show that the change rate of total-to-total efficiency according to the incidence angle change is unchanged although the turbine operates at the off-design condition.

• Journal of Mechanical Science and Technology
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• 제18권4호
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• pp.689-698
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• 2004

Uncertainties generated from the individual measured variables have an influence on the uncertainty of the experimental result through a data reduction equation. In this study, a performance test of a single stage axial type turbine is conducted, and total-to-total efficiencies are measured at the various off-design points In the low pressure and cold state. Based on an experimental apparatus, a data reduction equation for turbine efficiency is formulated and six measured variables are selected. Codes are written to calculate the efficiency, the uncertainty of the efficiency, and the sensitivity of the efficiency uncertainty by each of the measured quantities. The influence of each measured variable on the experimental result is figured out. Results show that the largest uncertainty magnification factor (UMF) value is obtained by the inlet total pressure among the six measured variables, and its value is always greater than one. The UMF values of the inlet total temperature, the torque, and the RPM are always one. The uncertainty percentage contribution (UPC) of the RPM shows th, lowest influence on the uncertainty of the turbine efficiency, but the UPC of the torque has the largest influence to the result among the measured variables. These results are applied to find the correct direction for meeting an uncertainty requirement of the experimental result in the planning or development Phase of experiment, and also to offer ideas for preparing a measurement system in the planning phase.

• 한국항공우주학회지
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• 제31권8호
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• pp.107-114
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• 2003

본 연구에서는 터빈 전효율의 불확도에 영향을 미치는 측정변수들의 불확도에 대한 영향을 실험의 결과로부터 분석하였다. 실험에 사용된 터빈은 축류형 3차원 단단터빈으로써 평균반경에서 반동도가 0.373이며 상온저압 상태에서 실험이 수행되었다. 입구전압력과 출구전압력에 의하여 발생되는 불확도는 전효율의 불확도에 전파되는 영향이 상당히 크게 나타나므로 상온저압시험에서는 높은 정밀도를 갖는 압력계를 사용하여야 한다. 측전변수의 불확도가 효율의 불확도에 차지하는 영향은 토오크에 의하여 발생되는 불확도가 가장 크게 나타났으며 회전수의 불확도가 가장 적었다. 토오크의 불확도 영향은 회전수의 증가에 따라 증가하는 경향이 있다. 전압력의 경우는 출그측에서의 불확도가 입구측에 비하여 영향력이 크게 나타났다.

• Journal of Mechanical Science and Technology
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• 제16권8호
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• pp.1154-1164
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• 2002

Losses on the turbine consist of the mechanical loss, tip clearance loss, secondary flow loss and blade profile loss etc.,. More than 60 % of total losses on the turbine is generated by the two latter loss mechanisms. These losses are directly related with the reduction of turbine efficiency. In order to provide a new design methodology for reducing losses and increasing turbine efficiency, a two-dimensional axial-type turbine blade shape is modified by the optimization process with two-dimensional compressible flow analysis codes, which are validated by the experimental results on the VKI turbine blade. A turbine blade profile is selected at the mean radius of turbine rotor using on a heavy duty gas turbine, and optimized at the operating condition. Shape parameters, which are employed to change the blade shape, are applied as design variables in the optimization process. Aerodynamic, mechanical and geometric constraints are imposed to ensure that the optimized profile meets all engineering restrict conditions. The objective function is the pitchwise area averaged total pressure at the 30% axial chord downstream from the trailing edge. 13 design variables are chosen for blade shape modification. A 10.8 % reduction of total pressure loss on the turbine rotor is achieved by this process, which is same as a more than 1% total-to-total efficiency increase. The computed results are compared with those using 11 design variables, and show that optimized results depend heavily on the accuracy of blade design.

• 전기학회논문지
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• 제62권9호
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• pp.1223-1227
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• 2013

If the factory test efficiency and field operation efficiency of water turbine are different from each other, issues for efficiency warranty can be raised. So, This paper shows the result for comparative analysis of field operating efficiency vs plant testing efficiency of the water turbine generator installed in agricultural reservoir. The efficiency of the induction generator is analyzed by the change of rotational speed with the parameter obtained by test, the efficiency of water turbine is calculated by the change of head with the design flow. Efficiency deviation of induction generator is lower but the variation of developed power is pretty high near the rated speed and the efficiency variation of water turbine is high by the fluctuation of head for constant flow. It was found that factory test efficiency and total efficiency of water turbine generator calculated according to the rotational speed are very close.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2003년도 제20회 춘계학술대회 논문집
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• pp.123-126
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• 2003

실험에서 측정변수에 발생되는 불확도가 터빈 전효율의 불확도에 미치는 영향을 실험을 통하여 분석하였다. 단단 축류형 3차원 터빈이 실험에 사용되었으며 평균반경에서 반동도가 0.373이며 상온 저압 상태에서 실험이 수행되었다. 입구/출구전압력에 의하여 발생되는 불확도는 터빈 전효율의 불확도로 전파되는 영향이 상당히 크게 나타나므로 상온저압시험에서는 높은 정밀도를 갖는 압력계가 필요하게 된다. 측정변수의 불확도가 전효율의 불확도에 차지하는 영향은 토오크에 의하여 발생되는 불확도가 가장 크게 나타났으며 회전수에 의한 불확도가 가장 적었다. 토오크의 불확도 영향은 회전수의 증가에 따라 증가하는 경향이 있다. 전압력의 경우는 출구측에서의 불확도가 입구측에 비하여 영향력이 크게 나타났다.

• 한국추진공학회지
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• 제14권5호
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• pp.65-71
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• 2010

75톤급 개방형 액체로켓용 터보펌프 터빈의 성능시험을 수행하였다. 넓은 압력비와 회전수 영역에서 터빈의 출력을 측정하였으며 이를 통해 터빈로터 전후의 유동특성을 파악하였다. 아울러, 터빈의 효율 변화 및 측정된 로터입구의 압력을 기 개발된 30톤급 터빈과 비교하였으며 이를 바탕으로 설계 의도에 부합되는 향상된 성능의 동익을 재설계하였다.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2010년도 제34회 춘계학술대회논문집
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• pp.38-44
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• 2010

75톤급 개방형 액체로켓용 터보펌프 터빈의 성능시험을 수행하였다. 넓은 압력비와 회전수 영역에서 터빈의 출력을 측정하였으며 이를 통해 터빈로터 전후의 유동특성을 파악하였다. 이와 함께 터빈의 효율 변화 및 측정된 로터입구의 압력을 기 개발된 30톤급 터빈과 비교하여 설계 의도에 부합되는 향상된 성능의 동익을 재설계하였다.

• Journal of Advanced Marine Engineering and Technology
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• 제21권4호
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• pp.421-429
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• 1997

This study is theoretically examined the influences on the performance of diesel engine super¬charged by exhaust gas turbine with the change of excess air factor, admission ratio, total efficien¬cy of turbine and compressor, scavenging pressure ratio, and scavenging temperature. In this study, all calculations are carried out by computer, and the theoretical engine performance is com¬pared with the actual engine performance which is offered from engine manufacturer. Following results are acquired by this study. The mean effective pressure is increased with decrease of excess air factor or increase of scavenging pressure ratio. As the admission ratio or total efficiency of tur¬bine is increased, the mean effective pressure is increased but the specific fuel consumption is decreased. Mean calculation error compared with the actual engine performance is under 5 per¬cents, therefore, this calculation method can be used in the design of diesel engine.