Jong-Gyu Kim

Fuel-Side Cold-Flow Test and Pressure Drop Analysis on Technology Demonstration Model of 75 ton-class Regeneratively-Cooled Combustion Chamber

․ Jong-Gyu Kim** ․ Byoungjik Lim* ․ Munki Kim** ․ Donghyuk Kang** ․ Seong-Ku Kim* ․ Hwan-Seok Choi*ABSTRACT Fuel-side cold-flow tests were performed on the technology demonstration model of a 75 ton-class liquid rocket engine combustion chamber for the first stage of the Korea space launch vehicle Ⅱ. Pressure drop in the cooling channels of the combustion chamber was measured by changing fuel mass flow rate through a pressure regulating system. Pressure d rop in each segment of the chamber could be obtained and a lot of pressure drop was caused by high flow velocity in the nozzle throat segment. The accuracy of a hydraulic analysis method for calculating a pressure loss in cooling channels could be verified by applying it to the cold-flow test conditions. 초 록 한국형발사체 1단에 사용될 75톤급 액체로켓엔진 연소기의 기술검증시제를 설계, 제작하여 연료 수류시험을 수행하였다. 가압압력을 조절하여 연료 유량을 변경함으로써 주어진 유량에서 발생하는 연소기 재생냉각 채널에서의 압력 손실을 측정하였다. 연소실 각 부에서의 압력 손실을 측정할 수 있었으며, 상당량의 압력 손실이 유속이 강한 연소실 노즐목부에서 발생함을 확인하였다. 주어진 연료 수류시험 조건에서 수력학 해석을 통하여 수력학 해석 방법의 정확도를 검증할 수 있었다. Key Words: Liquid Rocket Engine(액체로켓엔진), Regeneratively-Cooled Combustion Chamber( 재생냉각 연소기), Fuel-Side Cold-Flow Test(연료 수류시험), Pressure Drop Analysis(차압 해석)

Combustion Stability Rating Test of Liquid Rocket Engine Thrust Chamber

ABSTRACT As a evaluation method of combustion stability in a liquid rocket engine thrust chamber, external disturbance devices are used. In the paper, the study on pulse- gun ignition tests for a combustion stability rating test of a thrust chamber was performed. Charging volume of pulse-guns was determined by confirming the intensities of the pressure waves from the ignition tests in the cold-flow conditions. While using same injector head, combustion instabil ities were not encountered during 14 hot-firing tests without pulse-guns but combustion instabilitie s were triggered by pulse-gun ignition during 2 hot-firing tests. The results showed that the pulse-gu n ignition test could be the evaluation method and could reduce the hot-firing test number for the stability rating of a thrust chamber.초 록 액체로켓엔진 연소기의 연소안정성을 평가하기 위한 방법으로 연소 시 외부 교란을 공급하여 안정성 특성을 확인하는 방법이 사용된다. 본 논문에서는 연소기의 연소안정성 평가시험을 위한 펄스건 기폭시험에 대한 연구를 수행하였다. 비연소조건에서 펄스건 기폭시험을 수행하여 압력파의 강도를 확인함으로써 펄스건의 장약량을 결정하였다. 동일한 연소기 헤드에서 펄스건이 적용되지 않은 14번의 연소시험 동안 연소불안정이 나타나지 않았지만, 펄스건이 적용된 두 번의 탈설계점 조건에서는 연소불안정 현상이 발생하였다. 이로부터 펄스건을 이용한 기폭시험이 연소안정성 평가의 방법이 될 수 있음을 확인하였으며, 연소안정성 판정을 위한 연소시험 횟수를 줄일 수 있는 방법임을 제시하였다.Key Words: Combustion Stability Rating Test(연소안정성 평가시험), Thrust Chamber(연소기), Pulse-gun(펄스건), Combustion Instability(연소불안정)Received 27 August 2013 / Revised 6 March 2014 / Accepted 11 Ma rch 2014

Development of Sub-scale Combustor for a Liquid Rocket Engine Using Swirl Injector with External Mixing

The procedure of design and manufacture of sub-scale combustor using bipropellant swirl injector with external mixing for a liquid rocket engine are described. The results of cold flow test, ignition test and combustion test of the sub-scale combustor are also given in this paper. The sub-scale combustor uses liquid oxygen(LOx) and kerosene as propellants and has a injector head, an ablative material combustor wall and a water cooled nozzle. The injector head has LOx manifold, fuel manifold, fire face plate, one center swirl injector and 18 main swirl injectors. The cold flow, ignition and combustion tests were successfully performed without damage of combustor. Results of hot firing tests show that combustion efficiency meets the target of design and operations of start and stop cyclogram are stable and high frequency combustion instability does not occur.ﾖ⨀┍܀㘶〮㘵㬔C桥浩捡氠敮杩湥敲楮最