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침투경계조건과 CFD를 이용한 터빈 역형상 설계에 관한 연구
이은석(Eun Seok Lee),설우석(Woo Seok Seol) 대한기계학회 2007 대한기계학회 춘추학술대회 Vol.2007 No.5
In this paper, the inverse shape design is introduced using the permeable wall boundary condition. Inverse shape design defines the blade shape for the prescribed Mach numbers or pressure distribution on its surface. It calculates the normal mass flux from the difference between the calculated and prescribed pressure at the surface. A new geometry can be achieved after applying the quasi one-dimensional continuity equation from the leading edge to the trailing edge. For validation of this method, two test cases are studied. The first test case of inverse shape design illustrates the cosine bump with a strong shock. After seven geometry modifications, the shock-free bump geometry can be obtained. The second example concerns the redesign of a transonic turbine cascade. The initial isentropic Mach distribution has a peak on the upper surface. The target isentropic Mach number distribution was imposed smoothly. The peak of Mach distribution has disappeared at the final geometry. This proposed inverse design method has proven to be an efficient and robust tool in turbomachinery design fields.
조원국(Won Kook Cho),설우석(Woo Seok Seol) 한국항공우주연구원 2010 항공우주기술 Vol.9 No.1
액체산소/케로신을 사용하는 가스발생기 사이클 액체로켓엔진의 비추력 해석을 수행하였다. 본 해석 방법으로 재연한 300톤급 엔진의 시스템 성능은 문헌에 보고된 결과와 비교하여 비추력 0.1%, 최적 연소압 12%의 오차를 보였다. 오차의 주요 원인은 문헌에 공개되지 않은 서브시스템의 성능모델 차이와 가스발생기 생성물의 물성 모델 차이로 판단된다. 막냉각이 적용되는 30톤급 1단용 엔진의 경우, 연소압 68 bar에서 혼합비 2.2가 최적 비추력 조건인 것으로 평가되었으며 최적 조건은 주어진 성능 모델에 따라 달라질 수 있다. The analysis of specific impulse of the liquid rocket engine employing gas generator cycle with LOx/kerosene as propellant has been performed. The relative error of performance of 300 ton level engine is 0.1% for specific impulse and 12% for optimal combustion pressure comparing with the published data. The difference of the performance model and the material property models of gas generator product gas are the presumed major reason of discrepancy. The optimal condition of 30 ton level engine is combustion pressure of 68 bar and mixture ratio of 2.2 for maximum specific impulse. This optimal condition can be changed by performance models.
액체로켓 엔진 연소기에 장착되는 동축 스월 분사기의 액막 분열 및 분무 특성에 대한 수치적 연구
문윤완(Yoon Wan Moon),설우석(Woo-Seok Seol),윤영빈(Youngbin Yoon) 한국유체기계학회 2006 유체기계 연구개발 발표회 논문집 Vol.- No.-
This study investigated the characteristics of spray generated by a liquid-liquid co-axial swirl injector used in a combustor of the liquid rocket engine. The linear stability analysis[1] was introduced in liquid sheet breakup and Post[2]'s collision model which considers shattering was adopted on the collision model after breakup. Every model was implemented to KIVA[3], which was adopted as a solver. To validate the implemented models the case of low injection velocity which was similar to a injector installed in LRE main combustor was calculated and the result agreed well with test result.