Seong-Min Jeon

Rotordynamic Analysis of a High Thrust Liquid Rocket Engine Turbopump

A rotordynamic analysis is performed for a high thrust class liquid rocket engine turbopump considering the dynamic characteristics of ball bearings and pump noncontact seals. Complex eigenvalue problems are solved to predict the rotating natural frequencies and damping ratios as a function of rotating speeds. Synchronous rotor mass unbalance response and time transient response analyses are also performed to figure out the rotor critical speed and the onset speed of instability. From the numerical analysis, it is found that the rear bearing stiffness is most important parameter for the critical speed and instability because the 1st mode is turbine side shaft bending mode. The pump seal effect on the critical speed is enlarged as the rear bearing stiffness decreases and the front bearing stiffness increases會Ā᐀뢦⨀䀨鮬Ā저會Ā저Ⴇ⨀�鮬Ā㰀會Ā㰀梧⨀砩鮬ĀḀ會ĀḀ삧⨀좠ힲĀḀ會ĀḀᢨ⨀綴ԀĀ᐀會Ā᐀炨⨀衬綴܀܀좨⨀Ⴚ鞖ĀĀĀ會ĀĀ₩⨀ꂻ鞖ĀĀĀ會ĀĀ碩⨀䢰ힲĀĀĀ會ĀĀ킩⨀栂䦣ĀĀĀ會ĀĀ⢪⨀恑뎝Ā᐀會Ā᐀肪⨀硗뎝Ā᐀會Ā᐀�⨀쀢鮬ĀĀĀ會ĀĀカ⨀堣鮬ĀĀĀ會ĀĀ被⨀梡ힲĀ會Ā⨀綥Ā搀會Ā搀㢬⨀ࢢힲĀ저會Ā저邬⨀ꂢힲĀࠀ會Āࠀ⨀䂣ힲ

Performance Test of a 75-tonf Rocket Engine Turbopump

ABSTRACT Performance tests of a 75-tonf liquid rocket engine turbopump were conducted. The performance of sub-components - two pumps and a turbine - and their power matching were measured and examined firstly near the design speed under the LN2 and kerosene enviro nment. In the real propellant - LOX and kerosene - environment tests, design and off-design performance of turbopump were fully verified in regime of the rocket engine operation. During the off-design performance tests, turbopump running time was set longer than the engine operating time to verify the pump operability and set the pump inlet pressure close to design NPSHr to investigate pump suctio n capability in parallel. It has been found that developed-turbopump satisfied all of the engine required performances.초 록 75톤급 액체로켓엔진용 터보펌프 개발 시제에 대한 조립체 성능시험이 터보펌프 실매질 시험설비에서 수행되었다. LN2와 케로신을 적용한 첫 시험에서는 터보펌프 구성품들의 조립체 상태에서의 수력/공력 성능 및 출력 매칭 점검이 설계회전수 근방에서 이루어 졌으며 LOX와 케로신을 적용한 실매질 시험에서는 터보펌프의 설계성능 및 엔진운용영역 탈설계 성능 검증이 이루어졌다. 탈설계시험의 경우, 내구성 검증을 위해 엔진의 운용시간을 초과하여 터보펌프가 운용되었으며 펌프입구압력을 설계 요구유효흡입양정(NPSHr)에 가깝게 설정하여 흡입성능 검증을 병행하였다. 개발된 75톤급 액체로켓용 터보펌프는 성능, 운용시간의 엔진 요구규격을 만족시키는 것으로 확인되었다.Key Words:Liquid Rocket Engine(액체로켓엔진), Turbopump(터보펌프), Performance Test(성능시험), Kerosene(케로신), LOX(액체산소)Received 2 December 2015 / Revised 29 February 2016 / Accepted 7 March 2016

Performance Test of a 7 tonf Liquid Rocket Engine Turbopump

ABSTRACT Performance tests of a turbopump for the developing 7-tonf li quid rocket engine were conducted. The performance of turbopump components and their power matchin g were measured and examined firstly under the LN2 and water environment.. In the real prope llant(LOX and kerosene) environment tests, design and off-design performances of turbopump were ful ly verified. During the off-design tests, turbopump running time was set the same as engine operat ing time and pump inlet pressure were set lower than nominal operating value in order to investigate pump suction capability. It have been verified that subject turbopump satisfies required performance - flow rate, head, suction performance and operational time - in the operating regime of d eveloping liquid rocket engine.초 록 7톤급 액체로켓엔진용 터보펌프 개발 시제에 대한 조립체 성능시험이 수행되었다. LN2와 물이 적용된 상사매질 조립체 시험을 통해 터보펌프 단품 간 출력 매칭 및 조립체 레벨에서의 수력/공력 성능 검증이 선행되었으며 LOX와 케로신의 실제 운용 환경의 실매질 시험에서는 터보펌프의 설계점, 탈설계점 성능 검증시험이 이루어졌다. 탈설계시험은 엔진의 운용시간을 적용하여 이루어졌으며 펌프의 흡입성능 검증을 병행하였다. 개발된 7톤급 액체로켓용 터보펌프는 엔진운용영역에서 유량, 양정, 흡입 성능, 그리고 운용시간의 요구규격을 만족시키는 것으로 확인되었다.Key Words:Liquid Rocket Engine(액체로켓엔진), Turbopump(터보펌프), Performance Test(성능시험), Kerosene(케로신), LOX(액체산소)Received 27 December 2014 / Revised 8 March 2015 / Accepted 13 March 2015

Critical Speed Analysis of the Liquid Rocket Turbopump

Numerical analyses of critical speed and mass unbalance response are performed for a 30 ton thrust turbopump. The stiffness and damping of ball bearings and non-contact seals are quantified under aerodynamic and hydrodynamic loads induced by a fuel pump and turbine. Critical speed margin and tip displacements of the rotating parts are evaluated using a three-dimensional finite element method. The results are used to ensure the soundness of the rotordynamic design using an one-dimensional transfer matrix method. A further study shows that sufficient resonance margin may be assured via controlling the stiffness of the rotor support by employing an additional elastic ring to the bearing support.

Transient Heat Transfer and Structural Analyses for the Turbopump Turbine of a Liquid Rocket Engine

Thermal and structural finite element analyses were performed for the turbopump turbine bladed disk model with shroud of a liquid rocket engine. The only 1/80 part model was analyzed which consists of 3D eight node isoparametric solid elements. The applied loading history consists of a startup condition with a thermal spike and a steady state. Heat transfer coefficient on the blade was predicted using the commercial Navier-Stokes solver, Fluent. Transient thermal responses during startup and steady states were calculated using a 3D finite element code developed. Maximum stress and shroud tip displacement under the influence of centrifugal and thermal loading were also determined.