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이항기(Hang Gi Lee),신주현(Ju Hyun Shin),최창호(Chang Ho Choi) 대한기계학회 2017 대한기계학회 춘추학술대회 Vol.2017 No.11
This study investigates the performance of the supersonic impulse turbine of the 75 ton thrust liquid rocket engine. The Korea Space Launch Vehicle-II has the liquid rocket engine that generates the 75 ton-force thrusts. This engine uses the powerful turbopump in order to provide the propellants to the combustion chamber. The supersonic impulse turbines are employed in turbopumps to generate the high specific power in the condition of the small flow-rate turbine driving gas. This study conducted the performance test for the supersonic impulse turbine using a high-pressure air at the turbine test facilities in Korea Aerospace Research Institute. The tests were performed in the ranges including the design point and off-design points. Results show that the turbine performances meet the requirements. The characteristics of the turbine are analyzed.
정은환(Eunhwan Jeong),이항기(Hang-Gi Lee),박편구(Pyun-Goo Park),김진한(Jinhan Kim) 한국추진공학회 2011 한국추진공학회지 Vol.15 No.3
A velocity-compounded(VC) turbine of the 75ton turbopump was developed as an improved performance backup for a single-rotor base-line turbine. Curvic coupling was used for the connection between rotors and shaft. High temperature torsion test and spin test was performed for the curvic coupling design validation. Aerodynamic performance test revealed that the developed VC turbine can generate 20.5% higher specific power than the base-line turbine. It has been measured that 1<SUP>st</SUP> rotor of the subject turbine generates 74.1% of total power at design operating condition.
정은환(Eunhwan Jeong),이항기(Hang-Gi Lee),박편구(Pyun-Goo Park),홍문근(Moongeun Hong),김진한(Jinhan Kim) 한국추진공학회 2012 한국추진공학회 학술대회논문집 Vol.2012 No.5
75톤 추력급 터보펌프 터빈의 토크 특성을 성능시험 데이터를 바탕으로 분석하였다. 터빈의 비토크는 해석적으로 고정된 압력비에서 보정 선속도의 일차함수로 표현되며 이를 시험적으로 확인하였다. 일정 압력비 이상의 영역에서는 보정선속도-비토크 변화가 일정하게 나타나는 현상도 아울러 발견하였다. 분석된 토크 특성과 파이로 시동기의 시험 측정 데이터를 이용하여 터보펌프의 시동특성을 예측한 결과 터보펌프 설계회전수의 약 50%의 수준에 이르는 시간은 0.7초 이내인 것으로 나타났다. 파이로 시동기에서 터빈입구까지의 열손실은 최대회전수를 약 90 rpm 줄어들게 하는 것으로 예측되었다. Torque characteristics of a 75-tonf turbopump turbine was analyzed using the turbine performance test result. Specific torque of the subject turbine could be expressed as a linear function of corrected rotor speed at a fixed pressure ratio and it has been confirmed by the test result. It also found that corrected rotor speed-specific torque characteristics does not change anymore if the turbine pressure ratio is set bigger than a certain value. Using the turbine torque characteristics and pyro-starter performance test results, rotational speed development behavior of the turbopump was predicted. Prediction revealed that the lap time reaching 50% of turbopump design speed is less than 0.7 second. Effect of the thermal loss between pyro-starter and turbopump was negligible.
정은환(Eunhwan Jeong),이항기(Hang-Gi Lee),박편구(Pyun-Goo Park),홍문근(Moongeun Hong),김진한(Jinhan Kim) 한국추진공학회 2013 한국추진공학회지 Vol.17 No.1
Torque characteristics of a turbopump turbine was analyzed using the turbine performance test result. Specific torque of the subject turbine could be expressed as a linear function of corrected rotor speed at a fixed pressure ratio and it has been confirmed by the test result. It also found that corrected rotor speed-specific torque characteristics does not change anymore if the turbine pressure ratio is set bigger than a certain value. Using the turbine torque characteristics and pyro-starter performance test results, rotational speed development behavior of the turbopump was predicted. Prediction revealed that the lap time reaching 50% of turbopump design speed is less than 0.7 second. Effect of the thermal loss between pyro-starter and turbopump was negligible.
정은환(Eunhwan Jeong),이항기(Hang-Gi Lee),박편구(Pyun-Goo Park),김진한(Jinhan Kim) 한국추진공학회 2008 한국추진공학회 학술대회논문집 Vol.2008 No.11
슈라우드가 장착된 초음속 충동형 터빈의 팁간극에 따른 성능변화를 시험적으로 고찰하였다. 시험은 30톤급 터보펌프용 터빈을 이용하였으며 고압공기를 이용하여 다양한 압력비 및 회전수 범위에서 이루어졌다. 터빈의 효율민감도는 기준시험점에서 0.05의 매우 작은 값을 나타내었다. 터빈효율변화는 간극의 크기에 다라 비선형적으로 변화하였으며 고정된 압력비에서 효율민감도는 회전수의 세제곱에 비례하는 것으로 나타났다. 아울러 회전수에 무관하게 효율민감도는 기준시험 압력비에서 최소값을 보이는 것으로 나타났다. The effect of tip clearance on the performance of a supersonic impulse turbine was investigated experimentally. Test was performed using high pressure air in wide ranges of pressure ratio and rotational speeds. Test revealed that efficiency gradient of the subject turbine at a reference test point was a very low value of 0.05. Turbine efficiency was varied non-linearly with respect to tip clearance. It has been found that efficiency gradient is proportional to the cube of rotational speed at a fixed turbine pressure ratio. It also has been found that efficiency gradient shows its minimum at a reference test pressure ratio irrespective of rotational speeds.