• Journal of the Korean Society of Propulsion Engineers
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• v.10 no.4
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• pp.69-76
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• 2006

Elastic-viscoplastic structural analysis has been performed for regenerative cooling chamber of liquid rocket thrust chamber using Bodner-Partom visco-plastic model. Strain rate test was conducted for a copper alloy at various temperatures in order to get material constants of visco-plastic model used in the structural analysis. Material constants of visco-plastic model were obtained from strain rate test results and visco-plastic model was incorporated into finite element program, Marc, by means of a user subroutine. The structural analysis results indicated that the deformation of cooling channel is mostly caused by thermal loading rather than pressure loading and confirmed structural stability of the cooling channel under the operating condition.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.9
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• pp.903-913
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• 2011

A numerical study is carried out to analyze the steady three-dimensional turbulent flow through cylindrical and fan-shaped holes and the film cooling of these holes at low and high blowing ratios. Compressible Reynoldsaveraged Navier-Stokes equations and the energy equation are solved using a finite-volume-based solver, and a shearstress transport model is used as the turbulence closure. The effects of the compound angle, pitch to diameter ratio, and lateral expansion angle of the hole on the film-cooling effectiveness are evaluated by the film-cooling effectiveness. It is observed that the compound angle of the hole enhances the film performance for the cylindrical hole, and a small hole pitch induces interactions between the coolants from the adjacent holes, thus reducing the film-cooling performance.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.636-640
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• 2011

Film cooling technique has been applied to effectively reduce thermal load on liquid rocket combustion chambers by direct injection of a portion of propellant, which flows through the regeneratively cooling channels, into the chamber wall. This study developed a comprehensive model to quantitatively predict the effects of kerosene film cooling on propulsive performance and wall cooling at supercritical pressure conditions, and assessed the predictive capability against hot-firing tests of an actual combustor. The present model is expected to be utilized as a design and analysis tool to meet the conflicting requirements in terms of performance, cooling, pressure loss and weight.

• Journal of the Korean Society of Propulsion Engineers
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• v.16 no.5
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• pp.37-46
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• 2012

The calculation model for heat transfer analysis of rocket engine combustion chamber considering film-cooling has been established. Convective, radiative heat transfers and film-cooling effect in combustion chamber were evaluated using empirical equations especially for rocket engine combustors, and for heat transfer outward from chamber wall general convective and radiative equations were applied. Structural grid has been generated inside chamber wall for FVM calculations, and transient thermal analyses were carried out by time-marching techniques. LOx/kerosene rocket engine with chamber pressure of 50 bar has been analysed, and it is shown that, in that case, the film-cooling less than 4% remarkably contributes to reduce wall temperature, but the effect of the effect of film-cooling more than about 4% is not significantly increased.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.867-868
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• 2011

Transient Analysis on heat transfer of rocket engine combustion chamber and wall temperature variation was carried out, especially, calculations of LOx/kerosene rocket engine with/without fuel film-cooling were conducted. Convective and radiative heat flux inside combustion chamber wall were calculated by the empirical equations for rocket engine combustion, and conduction of wall interior was calculated by numerical method with 2D axisymmetric grid. In this calculations the transient variations of wall temperature, the location changes of peak temperature and so on affected by film-cooling were analyzed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.4
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• pp.2021-2026
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• 2013

In this study, the effect on the welding angle distortion was reviewed by carrying out a thermal elastic-plastic analysis while changing the cooling condition(width, length, and distance from weld torch to cooling torch) the back of the welding zone for the butt weld joint. The review results revealed that maximum 57% of reduction in the angle distortion was achieved when the distance between weld torch and cooling tip of 25mm, cooling length of 80mm, and cooling width of 30mm were maintained.

• Proceedings of the KSME Conference
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• 2005.11a
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• pp.34.2-34.2
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• 2005

• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.333-336
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• 2008

3MW 풍력발전기용 발전기의 구조적 특성을 소개하고 회전자의 동특성 해석을 수행하였다. 이 발전기는 증속기를 사용하였으며 정격속도는 1459 rpm 이며 30% over speed trip 조건을 적용하여 설계되었다. 회전자 pole에 전원 공급 없이 자기장을 만드는 영구자석을 사용하는 형태로 구조는 간단하다. 발전기의 냉각방법은 공극을 냉각하기 위하여 팬을 이용하여 공기를 순환하며 고정자 외형에는 냉각채널을 부착하여 냉각수를 순환한다. 회전기계의 설계 시에는 반드시 진동을 고려하여 가능하면 진동을 줄이는 방향으로 설계가 되어야 하며 회전축 계의 설계에 있어서는 계의 강도, 위험속도, 불평형 진동응답 및 안정성 등을 고려하여야 한다. 본 논문에서는 물리설계를 기본으로 하여 설계된 발전기의 형상을 간단하게 설명하고, 발전기의 회전자를 상용 유한요소 해석 프로그램인 ANSYS 를 이용하여 해석을 수행하였다. 해석절차는 정적해석을 수행하고 다음으로 모드해석을 수행 하였다. 모드형상에 따른 주파수를 표기하고 해석 결과를 나타내었다.

• Proceedings of the Korean Nuclear Society Conference
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• 1997.05a
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• pp.534-541
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• 1997

1000MWe급 피동형원자로기 안전계통 성능 및 RELAP5 코드의 적용성 평가를 목적으로 AP600을 참조노형으로 설정된 1000MWe급 대용량 피동형원자로에 대한 냉각재 상실사고를 모의 해석하였다. 대형냉각재상실사고시 발생되는 현상들은 기존 원자로와 큰 차이가 없고, 이들 현상을 모의하기 위한 모델링 요건들이 피동형계통 분석에 동일하게 요구되었으며, 계산된 PCT가 규제기관의 허용치에 충분한 여유도를 갖고 있어 대형냉각재상실사고시 충분한 노심냉각 능력을 갖는 것으로 평가되었다. 또한 안전주입 배관이 파단되는 소형냉각재 상실사고를 해석한 결과 KP1000의 피동안전계통은 ADS의 작동에 의하여 노심을 노출시키지 않고 적절한 사고완화 기능을 수행할 수 있는 것으로 분석되었다.

• Proceedings of the KIPE Conference
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• 2014.11a
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• pp.161-162
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• 2014

본 연구의 목적은 HVDC Valve module 및 valve tower에 유입되는 냉각 유체의 유동장 동적 해석과 동시에 냉각 유체의 동적 특성을 측정 비교함으로써 유동 해석의 적합성을 판단하고, HVDC valve module과 valve tower의 냉각 유로 및 관련 기구 설계의 기초 자료로 활용하는데 그 목적이 있다.