• 한국유체기계학회 논문집
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• 제18권4호
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• pp.22-29
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• 2015

In this study, an in-house program to predict steady state operation of micro gas turbines is constructed using MATLAB. The program consists of two parts: design and off-design simulations. The program is fully modular in its structure, and performance of each component (compressor, combustor, turbine, recuperative heat exchanger and pipe elements) is calculated in a separate calculation module using mass and energy balances as well as models for off-design characteristics. The off-design modules of compressor and turbine use performance maps, which are program inputs. The off-design operation of a micro gas turbine under development was predicted by the program. The prediction results were compared with those by commercial software, and the validity of the in-house program was confirmed.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2003년도 유체기계 연구개발 발표회 논문집
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• pp.80-87
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• 2003

Micro gas turbines are designed with low turbine inlet temperature and pressure ratio. To overcome the efficiency defect of the simple cycle, adoption of the recuperator is an inevitable choice. In addition to the design performance, we should also pay attention to the off-design performance of gas turbines since they usually operate at part-load conditions for a considerable amount of the time. This study aims at analyzing off-design performance characteristics of micro gas turbines and addressing the importance of the recuperator in the part load operation. Comparative analyses have been performed to evaluate the part load performance differences among various design and operating options : simple vs recuperative cycles, single vs two shaft configurations, various operating strategies for the single shaft configuration (fuel only control, variable speed operation, variable inlet guide vane control), and current vs advanced engines. Major finding is that maintaining turbine at high level is crucial in efficient operation of micro gas turbines.

• 한국유체기계학회 논문집
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• 제7권3호
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• pp.39-47
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• 2004

Micro gas turbines are designed with low turbine inlet temperature and pressure ratio. To overcome the efficiency defect of the simple cycle, adoption of the recuperator is an inevitable choice. In addition to the design performance, we should also pay attention to the off-design performance of gas turbines since they usually operate at part-load conditions lot a considerable amount of their lifetime. This study analyzes off-design performance characteristics of micro gas turbines and addresses the importance of the recuperation process doting the part load operation. Comparative analyses have been performed to evaluate the part load performance differences among various design and operating options : simple vs recuperative cycles, single vs two shaft configurations, various operating strategies for the single shaft configuration, and current vs advanced engines. Major finding is that maintaining high turbine exhaust temperature is crucial for efficient operation of micro gas turbines.

• 한국전산유체공학회지
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• 제4권2호
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• pp.17-30
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• 1999

The unsteady transitional boundary layer due to rotor-stator interaction was studied at two operation points, the design and one off design points. The off design point leads to lower blade loading and lower Reynolds number. A Navier-Stokes code developed in the previous study was parallelized to expedite computations. A low Reynolds number turbulence model was used to close the momentum equations. All computations show good agreement with experimental data. The wake induced transitional strip on the suction side of the stator is clearly captured at design point operation. There is no noticeable change in shape and phase angle of the wake induced strip even in the laminar sublayer. The wake induced transitional strip at off design point shows more complex structure. The wake induced transitional strip is observed only in the turbulent layer, and becomes obscure in the laminar sublayer and buffer layer. This behavior is probably consequent upon that the transition is governed by both wake induced strip and natural transition mechanism by Tollmien-Schlichting wave.

• 대한기계학회논문집
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• 제18권8호
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• pp.2167-2176
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• 1994

This paper presents some useful design criteria for the turbine cogeneration system through both the design and off-design analysis. Comparative analysis of the part load performance is carried out for several gas turbines which have different design parameters represented by the turbine inlet temperature and pressure ratio. It is shown that the variation in part load efficiency considerably depends on the design parameter. The off-design operation of the heat recovery steam generator is simulated by introducing adequate assumptions for the heat transfer process. It is turned out that the design parameters of heat recovery steam generator should be determined by considering the favorable operation at the off-design conditions.

• 소성∙가공
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• 제14권1호
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• pp.37-42
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• 2005

In order to invstigate the influence of die design variables on the quality of the sheared surface in cutting of sandwich sheet metals, the cut-off operation is carried out, which is the typical shearing process in sheet metal forming technology. For experiments we made the cut-off die which can be easily adjusted for die design variables such as blankholding force, pad force and clearance. The sandwich sheet metals considered are clad304(STS304-Al1050-STS304) and anti-vibration sheet metal. The shearing process is visualized by the computer vision system installed in front of the cut-off die and the sheared surface is measured and quantitatively compared with the help of the optical microscope after cut-off operation. From test results it is shown that the shearing mechanisms are different according the material of which sandwitch sheet metal is composed. The influence of die design variable is explored and we found optimal conditions for both sandwich sheet metals. It is expected that this investigation can be utilized to get the better sheared surface.

• 유공압시스템학회논문집
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• 제6권4호
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• pp.24-32
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• 2009

For a design of on/off solenoid actuator for valve actuating, designer must have the experimental knowledge as well as general electromagnetic formulas to design object. It is possible for theoretical knowledge to do the out-line design, but it is impossible to optimal design without experimental knowledge which only can be achieved through many repeated experiments. In addition, in present on/off type solenoid actuator field, the smaller, lightening, lower consumption power, high response time are effected as the most important design factor. So, experimental knowledge is more needed for optimal design of solenoid actuator. In this study, we derived the governing equations for optimal design of on/off solenoid actuator for valve actuating and developed a design program composed electromagnetic theories and experimental parameter values for inexperienced designers. And we proved the propriety of this program by experiments.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2004년도 춘계학술대회 논문집
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• pp.57-61
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• 2004

in order to improve the quality of the sheared surface in cutting of sandwich sheet metals the cut-off operation is mainly investigated which is the typical shearing process in sheet metal forming technology. For experiments the cut-off die is made which can be easily adjusted by die design variables such as blankholding force, pad force, and clearance. The sheet metals chose as specimen are clad304(STS304-Al1050-STS304) and anti-vibration sheet metal. The shearing process is visualized by the computer vision system installed in front of the cut-off die and the sheared surface before and after cut-off operation is measured and quantitatively compared with the help of the optical microscope. From test results the good sheared surface was shown when the clearance gets small with large blankholding force.

• 대한환경공학회지
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• 제38권5호
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• pp.249-254
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• 2016

본 연구에서는 상용 유리화설비 설계를 위한 기초자료에 도움이 되고자 용융공정에서 발생되는 배기가스의 특성과 배기가스 처리계통 운영사례를 조사하였다. 유리화설비 운영의 목적은 용융공정으로 투입된 방사성폐기물 내에 함유되어 있는 유해물질과 용융공정 내에서 발생된 다양한 화학종을 함유하고 있는 유해 배기가스를 처리하는 것이다. 유리화설비를 건설, 운영하기 위해서는 안전성 분석을 통한 인허가가 필수적이며, 부산물로 발생하는 방사성핵종이나 유해물질을 법적 환경배출규제치 이하로 처리하는 것이 매우 중요하다. 이를 위해서는 배기가스의 특성을 정확히 파악하여 그 특성에 따라 적절한 배기가스 처리공정을 설계해야 한다. 따라서 적절한 배기가스 처리계통을 설계하는 데는 폐기물 발생 특성, 용융로 특성, 배기가스 규제지침, 배기가스 발생 특성, 배기가스 처리장치에 대한 성능 평가 등의 광범위한 요소를 고려해야 한다.

• 한국해양공학회지
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• 제17권2호
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• pp.72-76
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• 2003

This paper presents the design concept and operation results of float-off for FSO (340,000 DWT Class, ELF AMENAM KPONO Project) built on the ground, without dry dock facilities. It was the first attempt to build FSO, completely, on the ground and launch it using DBU (Double Barge Unit, which was connected by rigid frame structure.) The major characteristics of FSO, which are similar to general VLCC type hull, including topside structure, weigh 51,000 metric ton. In order to have sufficient stability during the deck immersion of DBU, while passing through a minimum water plane area zone, proper trim control was completed with LMC (Load Master Computer). The major features of the monitoring system include calculation for transverse bending moment, shear force, local strength check of each connector, based on component stress, and deformation check during the load-out and float-off. Another major concern during the operation was to avoid damages at the bottom and sides of FSO, due to motion & movement after free-floating; therefore, adequate clearances between DBU and FSO were to be provided, and guide posts were installed to prevent side damage of the DBU casings. This paper also presents various measures that indecate the connector bending moment, damage stability analysis, and mooring of DBU during float off.