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Rotor Blade Sweep Effect on the Performance of a Small Axial Supersonic Impulse Turbine
Sooin Jeong,Byoungik Choi,Kuisoon Kim 한국항공우주학회 2015 International Journal of Aeronautical and Space Sc Vol.16 No.4
In this paper, a computational study was conducted in order to investigate the rotor blade sweep effect on the aerodynamics of a small axial supersonic impulse turbine stage. For this purpose, three-dimensional unsteady RANS simulations have been performed with three different rotor blade sweep angles (-15°, 0°, +15°) and the results were compared with each other. Both NTG (No tip gap) and WTG (With tip gap) models were applied to examine the effect on tip leakage flow. As a result of the simulation, the positive sweep model (+15°) showed better performance in relative flow angle, Mach number distribution, entropy rise, and tip leakage mass flow rate compared with no sweep model. With the blade static pressure distribution result, the positive sweep model showed that hub and tip loading was increased and midspan loading was reduced compared with no sweep model while the negative sweep model (-15°) showed the opposite result. The positive sweep model also showed a good aerodynamic performance around the hub region compared with other models. Overall, the positive sweep angle enhanced the turbine efficiency.
Rotor Blade Sweep Effect on the Performance of a Small Axial Supersonic Impulse Turbine
Jeong, Sooin,Choi, Byoungik,Kim, Kuisoon The Korean Society for Aeronautical and Space Scie 2015 International Journal of Aeronautical and Space Sc Vol.16 No.4
In this paper, a computational study was conducted in order to investigate the rotor blade sweep effect on the aerodynamics of a small axial supersonic impulse turbine stage. For this purpose, three-dimensional unsteady RANS simulations have been performed with three different rotor blade sweep angles ($-15^{\circ}$, $0^{\circ}$, $+15^{\circ}$) and the results were compared with each other. Both NTG (No tip gap) and WTG (With tip gap) models were applied to examine the effect on tip leakage flow. As a result of the simulation, the positive sweep model ($+15^{\circ}$) showed better performance in relative flow angle, Mach number distribution, entropy rise, and tip leakage mass flow rate compared with no sweep model. With the blade static pressure distribution result, the positive sweep model showed that hub and tip loading was increased and midspan loading was reduced compared with no sweep model while the negative sweep model ($-15^{\circ}$) showed the opposite result. The positive sweep model also showed a good aerodynamic performance around the hub region compared with other models. Overall, the positive sweep angle enhanced the turbine efficiency.
소형 초음속 터빈의 로터 블레이드 스윕 형상이 팁 누설 유동에 미치는 영향
정수인(Sooin Jeong),최병익(Byoungik Choi),오영택(Yeong taek Oh),김귀순(Kuisoon Kim) 한국추진공학회 2016 한국추진공학회 학술대회논문집 Vol.2016 No.12
본 논문에서는 슈라우드가 있는 로터 블레이드에 적용된 스윕 형상이 소형 초음속 축류 터빈 단에서 팁 간극을 통해 누설되는 흐름에 미치는 영향에 대하여 전산해석적인 방법으로 고찰하였다. 이를 위해 서로 다른 세 가지 스윕각(Sweep angle = -15°, 0°, +15°)을 적용하고 3차원 비정상 RANS 해석을 수행하여 그 결과를 서로 비교하였다. 로터 블레이드에 적용한 스윕각은 다양한 팁 누설현상에 영향을 주는 것으로 나타났다. 로터 스윕각이 클수록 팁 누설량은 감소하고 터빈효율은 증가하였다. This paper describes a computational investigation into the impact of a rotor blade sweep on the tip gap leakage flows in small supersonic impulse turbine with shrouded flat top rotor. For this purpose, three-dimensional unsteady RANS simulations have been performed with three different rotor blade sweep angles (-15°, 0°, +15°) and the results are compared with each other. The results show the rotor blade sweep affect the tip gap leakage mass flow rate and the turbine efficiency. The tip gap entrance flow blockage effect appears higher in BSW model (+15°)and the flow blockage effect of the rotor blade tip appears higher in FSW model (-15°) than others.
최적화기법을 이용한 초음속 충동형 터빈 노즐의 비대칭 설계
정수인(Sooin Jeong),최병익(Byoungik Choi),정은환(Eunhwan Jeong),김귀순(Kuisoon Kim) 한국추진공학회 2011 한국추진공학회 학술대회논문집 Vol.2011 No.5
본 연구에서는 초음속 충동형 터빈의 노즐에서 나타나는 유동의 과소·과대팽창 문제를 최적화 기법을 이용하여 비대칭형상을 포함해 설계함으로써 개선시키고자 하였다. 노즐 형상 설계를 위해 8개의 설계변수를 설정하였으며 목적함수로는 후류 영역 출구까지의 정효율이 최대가 되도록 하였다. 최적화에는 iSIGHT-FD가 사용되었으며 근사최적화를 위한 방법으로는 Radial Basis Function을 이용하였다. 노즐유동의 계산에는 상용 코드인 FLUENT 6.3을 사용하였으며 개선된 노즐의 정효율은 기존 대비 1.35% 증가하였고 손실계수는 19.85% 감소하였다. In this paper, the nozzle design with asymmetric configuration using the optimal method is used in order to improve the under- and over-expansion problem of the flow at the supersonic turbine nozzle. For the design of nozzle contour, 8 design variables are selected and the total-to-static efficiency from the nozzle inlet to the wake outlet is considered as the objective function to be maximized. The Fluent6.3 and the iSIGHT-FD program are used for calculation of nozzle flow and design optimization respectively. RBF(Radial Basis Function) method is chosen for approximate optimization algorithm. It is shown that the static efficiency of improved nozzle design increases 1.35% and loss coefficient decreases 19.85% as compared to baseline design.
정수인(Sooin Jeong),최병익(Byoungik Choi),이향기(Hanggi Lee),김귀순(Kuisoon Kim) 한국추진공학회 2017 한국추진공학회 학술대회논문집 Vol.2017 No.5
액체 로켓 엔진의 터보펌프를 구동하는 고압 초음속 충동형 터빈의 로터 블레이드에 3차원 설계요소를 적용하여 성능을 개선하기 위한 연구를 진행하고 있다. 본 논문에서는 기존 설계된 터보펌프용 터빈의 로터 블레이드 형상을 바탕으로 로터 블레이드에 스윕(sweep)과 상반각(dihedral) 등과 같은 중첩선(stacking line) 변화를 통한 3차원 형상을 적용하고 CFD를 이용한 3차원 유동 해석을 수행한 후, 각각의 설계 요소에 대한 터빈성능 특성 변화를 면밀히 검토하고 그 결과를 정리하였다. We are working on improving the performance by applying the three-dimensional design element to the rotor blades of high pressure supersonic impulse turbine that drives turbo pump of liquid rocket engine. In this paper, based on the shape of a rotor blade of a turbopump turbine designed in the past, a three-dimensional shape is applied to a rotor blade through a stacking line change such as sweep and dihedral. After performing the flow analysis, the changes in the turbine performance characteristics for each design element were carefully examined and the results were summarized.