• 동력기계공학회지
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• 제13권5호
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• pp.52-58
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• 2009

A gas turbine consists of an upstream compressor and a downstream turbine with a combustion chamber, and also the compressor and the turbine are generally coupled using a single shaft. Many casing bolts are used to assemble two horizontally separated casings, the gas turbine casing and the compressor casing, in both of axial and vertical directions. Because drilled holes for casing bolts in vertical direction are often too close to drilled holes for casing bolts in axial direction, one can observe cracks in the area frequently during operations of a gas turbine. In this study of the root cause analysis for the cracking initiating from the drilled holes of the casings of a gas turbine, the finite element analysis(FEA) was applied to evaluate the thermal and mechanical characteristics of the casings. By applying the field operation data recorded from combined cycle power plants for FEA, thermal and thermo-mechanical characteristics of a gas turbine are analyzed. The crack is initiated at the geometrical weak point, but it is found that the maximum stress is relieved when the same type of cracks is introduced on purpose during FEA. So, it is verified that the local fracture could be delayed by machining the same type of defects near the hole for casing flange bolts of the gas turbine, where the crack is initiated.

• 한국전산구조공학회논문집
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• 제29권4호
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• pp.347-354
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• 2016

가스 터빈은 기동 및 정지 횟수가 많기 때문에 열피로나 취화 현상으로 인한 가스터빈 케이싱의 균열 또는 케이싱의 플랜지면에서 고온고압 가스의 누설이 발생할 가능성이 높다. 따라서 가스터빈 케이싱의 구조안전성 및 플랜지면에서의 누설평가는 반드시 수행되어야 하는 부분이다. 본 논문에서는 유한요소해석을 바탕으로 터빈 케이싱의 ASME B&PVC VIII-2 구조안전성 평가 및 접촉압력을 통한 누설 평가 그리고 볼트의 구조안전성 평가를 진행하였다. 또한 가스터빈 케이싱의 유한요소모델링 및 해석/평가 방법을 제안하여 가스터빈 개발에 활용할 수 있게 하였다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 추계학술대회
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• pp.557-561
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• 2004

The hot gas casing of gas turbine has operated high temperature and thermal gradient. The structure safety of hot gas casing will be highly depend on the thermal stress. In this paper, flow and thermal stress analysis of hot gas casing is carried out using ANSYS program. The obtained temperature data by flow analysis of hot gas casing apply the load condition of the thermal analysis. The thermal stress analysis is carry out the elastic-plasticity analysis. The pressure, temperature and velocity of the flow and thermal stress of the hot gas casing are presented.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2011년도 춘계학술대회 논문집
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• pp.913-914
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• 2011

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2013년도 추계학술대회 논문집
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• pp.163-165
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• 2013

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2000년도 유체기계 연구개발 발표회 논문집
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• pp.211-218
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• 2000

Off-design experimental performance was investigated for a small centrifugal compressor, whose impeller diameter is about 125mm, used in an industrial gas turbine. Test rig was designed and manufactured with a radial inflow turbine and a combustor to supply driving power to the compressor. Static pressure was measured on the casing of the impeller, vaneless diffuser, vaned diffuser and volute. Total pressure was obtained using specially fabricated rakes at the vaned diffuser throat and exit. Circumferential nonuniformity was found, near surge, in the Impeller, vaned diffuser and volute region. Spanwise nonuniform flow from the impeller affected the total pressure defects in the vaned diffuser region. Static pressure distortion in the circumferential direction in the volute was found near surge, where the minimum occurred near 140 degree position.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2004년도 제22회 춘계학술대회논문집
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• pp.622-627
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• 2004

There are many difficulties in realizing Ultra-micro gas turbine system. Among them, the effects of tip clearance upon the micro turbine flowfield are discussed in this paper. The flowfield was investigated numerically with the Reynolds-averaged three-dimensional thin-layer Navier-Stokes equations. Calculations were conducted with clearance height from 0％ to 10% of the passage height. Leakage mass flow and deterioration of efficiency are proportional to the clearance height for the clearance height larger than 4%. However, in the case of 2% clearance, leakage flow is significantly reduced due to relative motion of the casing and as a result deterioration of efficiency is very small. It is difficult to control tip clearance in micro turbines, but the results of this study indicate that if the clearance height is controlled within a few per-cent of passage height, deterioration of stage performance will be small.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 1998년도 유체기계 연구개발 발표회 논문집
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• pp.191-197
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• 1998

The recent results of the engine development performed in this you on Turbogreen 1200, the first industrial gas turbine engine developed in Korea, are presented. In order to improve the engine performance and structural stability from the first prototype engine, several variants of the engine and major components such as combustor and rotor assembly have been developed and tested. This paper shows these results especially focused on the engine test and performance analysis, in which test system, instrumentation and data processing are discussed as well. The engine performance and its trend give relatively good coincidence with the design ones. At design power of 1.2MW, the thermal efficiency of the engine is estimated over $25\%$ which is below the design target of $27.2\%$. This gap of efficiency is caused mainly by large tip clearance between turbine blades and casing. Considering high design efficiency superior to those of other competitive engines in this power class, Turbogreen 1200 would have a strong competition in its performance if the design efficiency is achieved by further developments such as tip clearance control, which are very possible and natural in final mass production of the developed gas turbine engine.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2012년도 추계학술대회 논문집
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• pp.464-469
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• 2012

발전소에 있어서, 발전소가 높은 신뢰성이 있기 위해서는 안정적인 회전체의 동적 운동이 확보되어야 하므로, 장기간 안전하게 운전하기 위하여 축 진동은 매우 중요한 요소중의 하나이다. 하지만 어느 복합발전소에서는 오일 탄화물에 의한 비정상적인 1X 성분의 축 진동 상승으로 가스터빈이 여러번 정지되었다. 본 논문에서는 가스터빈 Exhaust 케이싱 베어링에서 발생한 이상진동에 대하여 어떻게 현장조치를 하였는지를 기술하였다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 춘계학술대회논문집
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• pp.46-50
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• 2007

The nuclear power plant's turbine-generator system had been suffered form some problems, such as high shaft vibration, generator casing crack, stator coil water leakage, high $H_2$ gas consumption rate. Those kinds of problems were related to high vibration. So nuclear plant decided to replace generator in order to reduce rotor high vibration and high thermal sensitivity. A series of effort to reduce turbine-generator vibration was carried out as followings, first of all, replacement of generator, analysis of turbine-generator vibration, LP B rotor shop balancing, improvement of LP B/Gen coupling run-out, improvement of Generator basement and field balancing. Finally the nuclear turbine-generator's shaft vibration was reduced below $60{\mu}m$ from over $200{\mu}m$ which is very excellent vibration in nuclear turbine-generator in Korea.