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정동호(Dongho Jung),오승협(Seunghyub Oh) (사)한국CDE학회 2013 한국 CAD/CAM 학회 학술발표회 논문집 Vol.2013 No.1
There are a lot of method in pipes connecting but, most widely use weld. Not only general industry but space launch vehicle use to connecting pipes welding. To extend pipes many choices are available but welding is permanently join the pipes without leak. However pipe welding is not easy to install. During the welding if occur welding part stress concentration and a blow hole will be developed critical defect. Beside welding the pipes naturally grows welding beads It’s inside and outside. Accidentally welding back bead bigger than expect. It will be orifice not intentionally. On this paper deal with flow influence in pipe welding joint back bead and check the optimal point of back bead status a point of view flow.
정동호(Dongho Jung),조기주(Kiejoo Cho),오승협(Seunghyub Oh) (사)한국CDE학회 2012 한국 CAD/CAM 학회 학술발표회 논문집 Vol.2012 No.2
The liquid propulsion launch vehicle have propellant supply system to supply propellant to engine. This supply system is called feeding system. Which is connected from propellant tank to engine. The feeding system is affected by launch vehicle configuration and onboard equipment arrangement. Among them most important factor is launch vehicle configuration. This paper have a mean to check character of several configurations from joint part between propellant tank and feeding line. To design joint part concept, we was performed case study from overseas. From the result of case study, we designed several concept. Which had performed CFD analysis.
정동호(Dongho Jung),조기주(Kiejoo Cho),오승협(Seunghyub Oh) 한국추진공학회 2011 한국추진공학회 학술대회논문집 Vol.2011 No.11
추진제 탱크와 배관의 연결부에 대한 개념 설계단계로 해외 발사체의 배관 연결부를 조사하였고, 그 결과를 토대로 몇가지 대표 형상을 선정하여 유동해석을 수행하였다. 유동해석 결과 배관의 연결부 중 제일 유동특성이 좋은 것을 찾을 수 있었다, 하지만 큰 차이는 없었다. 그 이유는 배관이 길어서 배관 내부를 유체가 흐르면서 배관 내부 유동이 안정되는 것으로 판단된다. The concept design of joint part between propellant tank and feeding line for launch vehicle has been performed with the case study of oversea launch vehicles. we carried out, for the several configurations, numerical flow analyses to find the joint configuration which promises high flow uniformity at the outlet. There were a little difference in the numerical results, because the length of feeding lines are sufficiently long to stabilize the flow field.
재 점화가 있는 가압식 추진기관의 액체산소 탱크 가압 헬륨량 산정
조규식(Gyusik Cho),정영석(Youngsuk Jung),오승협(Seunghyub Oh) 한국추진공학회 2011 한국추진공학회 학술대회논문집 Vol.2011 No.11
극저온 추진제 탱크 속에서 가압 가스는 열손실에 의해 수축하고 추진제는 기화한다. 재 점화가 있는 추진기관의 경우 무추력 비행구간에서 극저온 추진제가 가압가스와 넓은 표면적으로 접촉하기 때문에 이러한 현상이 증대된다. 가압 가스량을 산정함에 있어 이러한 탱크 내부 열 물질 전달 현상을 고려하여야 한다. 무추력 비행구간에서 열 물질 전달 준 평형상태에 도달한다는 가정 하에 평형압력 계산절차를 제시하였다. 이를 적용하여 Falcon-1 발사체 2단에 탑재된 헬륨량을 산정하였다. In a cryogenic propellant tank the pressurant is contracted due to heat loss and the propellant itself evaporates. On a restartable propulsion system such phenomena are more intensive because the propellant contacts with the pressurant on the larger surface during the coast flight. Such heat and mass transfer phenomena should be considered for estimating the amount of pressurant. On the hypothesis that the heat and mass transfer quasi-equilibrium is achieved during the coast flight, the calculation process of the equilibrium pressure is presented. On the process the amount of loaded helium on the Falcon-1 second stage is calculated.