• Proceedings of the KAIS Fall Conference
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• 2005.05a
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• pp.71-74
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• 2005

본 논문에서는 폐목재의 재활용을 위한 1차 파쇄기의 다음 공정인 2차 파쇄기에 대해 경계조건과 하중조건을 적응하여 유한요소법에 의한 ANSYS로 구조해석과 모달해석을 수행하여 응력(stress), 변형률(strain)을 구하고 구조적 타당성을 검토하였다. 이는 안전성을 고려한 설계의 기초 자료가 되며 고유진동수(natural frequency)를 구하여 모터의 회전을 제어함으로서 공진(resonance) 현상을 피하는데 있다.

• Proceedings of the KIEE Conference
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• 2005.07b
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• pp.1518-1520
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• 2005

본 논문에서는 실제 부하가 연결된 스위칭 전력 변환기 동특성의 부하 영향(leading effect)을 수식적으로 나타내고 해석하였다. 부하 시스템을 extra element로 고려하고 Middlebrook의 extra element theorem의 결과를 적용하였다. 그리고 스위칭 전력 변환기의 소신호 동특성에 대한 부하 영향을 해서하기 위해서 보드 선도 해석 방법을 이용하였다.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 1995.05a
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• pp.123-128
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• 1995

고등기술연구원에서 수행하고 있는 IGCC 연구프로그램의 일부로 이루어지고 있는 석탄가스연소가스터빈 시스템의 공정개발을 위한 해석체계를 소개하였고, 지금까지 이루어진 해석결과들을 제시하였다. 본 해석체계는 가스터빈 시스템해석을 위한 사이클해석. 구성요소인 압축기, 연소기, 터빈에 대한 해석모듈들로 구성하였으며, 각 해석모듈은 구성요소에 대한 전문적인 열유동장 해석방법을 채택한다. 각 해석모듈간의 상호작용 및 해석결과들의 종합을 통하여 IGCC용 가스터빈 공정개발을 위한 기초적인 자료제공이 가능하다.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.12
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• pp.1359-1365
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• 2014

In this study, 1-way fluid structure interaction analysis(FSI) for the shutter, component of side jet thruster was performed to evaluate the safety. Driving torque to open nozzle, thermal and high pressure load of hot gas was applied to shutter. Thus, the shutter must be designed to endure this load during combustion. We carried out computational fluid dynamics analysis to obtain the pressure, temperature, and heat transfer coefficient of hot gas of side jet thruster. We then used the data as the load condition for a thermal structural analysis using a mapping method. The locations with the maximum stress and temperature distributions were found. We compared the maximum stress with the tensile stress of shutter material according to temperature to evaluate the safety. We also analyzed the radial deformation of the shutter to set the proper interface gap with the side jet thruster parts.

• Journal of the Korean Society of Propulsion Engineers
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• v.16 no.4
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• pp.1-8
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• 2012

In this study, numerical method, stage stacking method based on the result of numerical method and scaled stage stacking method have been applied to predict the performance of a multi-stage axial compressor with inlet guide vane. The results obtained through three different methods for off-design conditions were compared with performance test data. And the effect the angle of variable inlet guide vane was also investigated. The three-dimensional numerical simulation has been performed by using flow analysis program, $FLUENT^{TM}$ 6.3 and the performance prediction based on the stage stacking method has been performed with compressor analysis code from NASA.

• Journal of the Korean Society of Propulsion Engineers
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• v.24 no.5
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• pp.21-33
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• 2020

In this study, the program for system analysis of an expander cycle rocket engine using liquid hydrogen as a fuel was developed. The properties of hydrogen were considered by the ratio of isomers with temperature. The analysis procedure was established with the open and closed types of the expander cycle engine and the simulation methods were suggested for each component. To validation of the analysis program, we compared the performance of the engine operating point and the analysis results performed overseas for Vinci and SE-21D, which are expander cycle engines. As a result of the analysis, the main performance factors of the system, such as the mass flow of the propellant, specific thrust, and power, except for some of the inaccurate input information, showed high accuracy with an error of around 1-2%.

• Journal of the Korean Society of Propulsion Engineers
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• v.9 no.4
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• pp.39-47
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• 2005

The structural analysis and water pressure tests are performed for liquid rocket thrust chamber regenerative cooling channel specimens at room temperature condition. Material properties of copper alloy to be used in the elastic-plastic structural analysis are obtained by uniaxial tension test at room temperature. The plate-type cooling channel specimens are manufactured and performed water pressure test to verify the analysis results. The results of elastic-plastic structural analysis and water pressure test show resonable agreements though with minor differences and it is revealed that structural stability of regenerative cooling channel is highly affected by the manufacturing tolerances due to very thin cross-sectional thickness of the cooling channel.

• Journal of the Korean Society of Propulsion Engineers
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• v.16 no.6
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• pp.32-40
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• 2012

For predicting eigenfrequency and initial growth rate of combustion instabilities in lean premixed gas turbine combustor, linear thermoacoustic analysis model was developed in the current paper. A model combustor was selected for the model validation, which has well-defined inlet and outlet conditions and a relatively simple geometry, compared to the combustor in the previous works. Analytical linear equations for thermoacoustic waves were derived for a given combustion system. It was found that the prediction results showed a good agreement with the measurements, even though there was underestimation for instability frequencies. This underestimation was more obvious for a longer flame (i.e. wider temperature distribution) than for a shorter flame.

• Aerospace Engineering and Technology
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• v.1 no.2
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• pp.1-10
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• 2002

Flow computations around forward sweep wing small aircraft have been conducted in this study. The main-wing of the forward-wing small aircraft is composed of two planforms: the inboard wing section with backward sweep angle which is known as strake and the outboard wing section with forward sweep angle. The geometrical discontinuity or kink generated by the combination of these two different planforms requires detailed flow analysis around wing. Four different solvers were used to calculate aerodynamic data and the accuracy of each method is examined. For the convenience of grid generation over the aircraft geometry, the overset grid method was applied. Through this calculation, the basic aerodynamic data of the forward-wing aircraft were provided and the aerodynamic characteristics of the wing is expounded.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.6
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• pp.18-25
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• 2016

Enhanced tubes are used widely in the evaporators of large tonnage compression-type refrigerators. The evaporators consist of tube bundles, and the refrigerant properties are dependent on the locations in the tube bundles. In particular, the saturation temperatures of low pressure refrigerants (R-11, R-123) are strongly dependent on the locations due to the saturation temperature-pressure curve characteristics. Therefore, for the proper design of evaporators, local property predictions of the refrigerants are necessary. In this study, a computer program that simulates the flooded refrigerant evaporators was developed. The program incorporated theoretical models to predict the refrigerant shell-side boiling heat transfer coefficients and pressure drops across the tube bundle. The program adopted an incremental iterative procedure to perform row-by-row calculations over the specified incremental tube lengths for each water-side pass. The program was used to simulate the flooded refrigerant evaporator of the "T" company operating with R-123, which yielded satisfactory results. The program was extended to predict the performance of the flooded refrigerant evaporator operating with R-11, R-123, and R-134a. The effects of bundle aspect ratio are investigated.