고압 유동조건에서의 액체 램제트 엔진의 분무특성

윤현진 ( H. J. Youn ),이충원 ( C. W. Lee ) 한국분무공학회 2004 한국액체미립화학회지 Vol.9 No.2

N/A In a liquid-fueled ramjet engine, the insufficient mixing and evaporation result in the low combustion efficiency and combustion instability. Improving its characteristics and devising a means of fuel droplets with air may compensate these disadvantages of liquid fuel ramjet engine. The jet penetrations of various fuel injectors were measured to investigate the spray characteristics of a liquid-fueled ramjet engine under high pressure air-stream conditions. The penetrations in high pressure conditions are smaller than the values calculated from Inamura`s or Lee`s equations, and the jet penetrations in the high pressure conditions have a similar tendency. In the dual orifice injectors, the jet penetrations of rare orifice is rapidly increased due to the reduction of the drag, which is created by the jet column of front orifice. The jet penetration of rare orifice is increased because of the drag reduction created by the jet column of the front orifice. Because of the drag reduction formed by the column of jet, the jet penetration in the rear orifice of dual orifice injector is much larger than the jet penetrations of single orifice injector. As the distances of the orifice are increased, the jet penetrations of the rear orifice decrease.

Atomization Improvement of a Liquid Jet with Wall Impingement and its Application to a Jet Engine Atomizer

( Seiichi Shiga ) 한국액체미립화학회 2005 한국액체미립화학회 학술강연회 논문집 Vol.2005 No.-

In the present study, capability of improving the liquid atomization of a high-speed liquid jet by using wall impingement is explored, and its application to a jet engine atomizer is demonstrated. Water is injected from a thin nozzle. The liquid jet impinges on a wall positioned close to the nozzle exit, forming a liquid film. The liquid film velocity and the SMD were measured with PDA and LDSA, respectively. It was shown that the SMD of the droplets was determined by the liquid film velocity and impingement angle, regardless of the injection pressure or impingement wall diameter. When the liquid film velocity was smaller than 300 m/s, a smaller SMD was obtained, compared with a simple free jet. This wall impingement technique was applied to a conventional air-blasting nozzle for jet engines. A real-size air-blasting burner was installed in a test rig in which three thin holes were made to accommodate liquid injection toward the intermediate ring, as an impingement wall. The air velocity was varied from 41 to 92m/s, and the liquid injection pressure was varied from 0.5 to 7.5MPa. Combining wall impinging pressure atomization with gas-blasting produces remarkable improvement in atomization, which is contributed by the droplets produced in the pressure atomization mode. Comparison with the previous formulation for conventional gas-blasting atomization is also made, and the effectiveness of utilizing pressure atomization with wall impingement is shown.

Atomization Improvement of a Liquid Jet with Wall Impingement and its Application to a Jet Engine Atomizer

Shiga, Seiichi The Institute for Liquid Atomization and Spray Sys 2006 한국액체미립화학회지 Vol.11 No.3

In the present study, capability of improving the liquid atomization of a high-speed liquid jet by using wall impingement is explored, and its application to a jet engine atomize. is demonstrated. Water is injected from a thin nozzle. The liquid jet impinges on a wall positioned close to the nozzle exit, forming a liquid film. The liquid film velocity and the SMD were measured with PDA and LDSA, respectively. It was shown that the SMD of the droplets was determined by the liquid film velocity and impingement angle, regardless of the injection pressure or impingement wall diameter. When the liquid film velocity was smaller than 300m/s, a smaller SMD was obtained, compared with a simple free jet. This wall impingement technique was applied to a conventional air-blasting nozzle for jet engines. A real-size air-blasting burner was installed in a test rig in which three thin holes were made to accommodate liquid injection toward the intermediate ring, as an impingement wall. The air velocity was varied from 41 to 92m/s, and the liquid injection pressure was varied from 0.5 to 7.5 MPa. Combining wall impinging pressure atomization with gas-blasting produces remarkable improvement in atomization, which is contributed by the droplets produced in the pressure atomization mode. Comparison with the previous formulation for conventional gas-blasting atomization is also made, and the effectiveness of utilizing pressure atomization with wall impingement is shown.

SIMULINK와 LabVIEW를 이용한 소형 터보제트 엔진의 실용 통합 상태 진단 시스템 개발

공창덕(Changduk Kong),고성희(Seonghee Kho),박길수(Gilsu Park),박광림(Gwanglim Park) 한국추진공학회 2013 한국추진공학회지 Vol.17 No.1

In currently developed engine condition monitoring systems, most field engine maintenance engineers have difficulties to use them in fields due to complexity, unpractical use, lack of understanding, etc. Therefore a practical usable engine condition monitoring system must be needed. This work proposes a practical performance condition monitoring of a small turbojet engine through comparing between the on-line performance monitoring data and the initial clean performance data calculated by the base engine performance model. Moreover the proposed monitoring system checks the gas path components’ on-line health condition through comparing the component performance characteristics between the running engine represented as a deteriorated engine or a degraded engine and the base engine performance model represented as a clean engine. The proposed condition monitoring system is coded in a friendly GUI type program for easy practical application by a commercial tool, MATLAB/SIMULINK and LabVIEW.

MUSIC 알고리즘을 이용한 JEM 신호의 Chopping 주파수 추출

송원영,김형주,김성태,신인선,명로훈 한국전자파학회 2019 한국전자파학회논문지 Vol.30 No.3

Jet engine modulation(JEM) signals are widely used in the field of target recognition along with high-range resolution profile and inverse synthetic aperture radar because they provide specific information of the jet engine. To obtain the number of blades of the jet engine, the chopping frequency proportional to the number of blades must be extracted. In the conventional chopping frequency extraction method, an initial threshold value is defined and a method of detecting the chopping peak is used. However, this detection method takes time depending on the signal due to repetitive detection. Thus, in this study, we proposed to extract the chopping frequency using MUltiple SIgnal Classification(MUSIC) algorithm. We applied the MUSIC algorithm to a given JEM signal to find the chopping frequency and determine the blade number candidates. We also applied the MUSIC algorithm to other chopping frequency extractions to determine the score of the candidate groups. Unlike the conventional detection algorithm, which requires repetitive frequency detection, MUSIC algorithm quickly detects the accurate chopping frequency and reduces the calculation time.

부유식 일체형 소형워터제트 추진시스템 개발

정재훈(Jae Hoon Jeong),이중섭(Chung Seob Yi),이치우(Chi Woo Lee) 한국생산제조학회 2016 한국생산제조학회지 Vol.25 No.1

This paper presents the development of a floating outboard type of compact water jet propulsion system. The planning case of the water jet system is developed by performing precision processing after manufacturing FRP (Fiber Reinforced Plastics) from plug mold casting. This system is composed of an intake, impeller, diffuser, reverse bucket, and main shaft. In addition, a rebuilt engine was applied through marine engineering. The water jet propulsion system performance was verified to discharge a maximum 0.29 m3/s of flow rate and 37 m/s of flow velocity in a test pool on land. A field test was performed by installing the water jet propulsion device on board a ship that was tested off the coast of Korea. The weight of the hull, engine, and other equipment was approximately 1.2 tons, and the sailing speed was a maximum 22 knots at 3,600 rpm.

제트 엔진 변조신호에서 주파수 마스킹을 이용한 표적의 특징 추출 및 식별

김시호(Si-Ho Kim),김찬홍(Chan-Hong Kim),채대영(Dae-Young Chae) 한국전자파학회 2014 한국전자파학회논문지 Vol.25 No.4

본 논문은 항공기의 JEM(Jet Engine Modulation) 신호를 분석하여 표적을 식별하는 방법에 관한 것이다. 제트 엔진의 각 단의 날개 수 정보로부터 계산된 하모닉 주파수 마스크를 이용하여 스펙트럼을 분석함으로써 엔진 기종을 식별하는 방법을 제안한다. 기존의 방법처럼 각 단의 쵸핑(chopping) 주파수를 찾기 위한 복잡한 논리적 알고리즘이나 스펙트럼 비교 방법처럼 미리 모사된 엔진 스펙트럼 DB(Database)를 필요로 하지 않으며, 엔진 DB의 날개 수 정보를 이용하여 추출한 하모닉 성분을 비교함으로써 식별이 가능하다는 장점을 가진다. 또한, 정밀 축회전속도(spool rate)를 찾는 방법을 제시함으로써 날개 수 추정이나 하모닉 주파수의 위치 계산에서 오류를 줄일 수가 있다. This paper deals with the method to classify the aircraft target by analyzing its JEM signal. We propose the method to classify the engine model by analyzing JEM spectrum using the harmonic frequency mask generated from the blade information of jet engine. The proposed method does not need the complicated logic algorithm to find the chopping frequency in each rotor stage and the pre-simulated engine spectrum DB used in the previous methods. In addition, we propose the method to estimate the precise spool rate and it reduces the error in estimating the number of blades or in calculating the harmonic frequency of frequency mask.

터빈엔진시험을 통한 제트연료 변경에 따른 엔진성능 변화 연구

김유일(Youil Kim),민성기(Seongki Min) 한국추진공학회 2011 한국추진공학회지 Vol.15 No.2

The engine ground and altitude tests were carried out to investigate the effect of jet fuel alteration on the performance of a small turbojet engine. JP-S was supplied 8% higher than JP-8 by fuel metering system at the same command. The employment of JP-S showed the similar starting characteristic to that of JP-8, however, difference in the ignition time and acceleration rate of engine speed due to the difference of fuel flow rate by fuel metering system was observed. In spite of jet fuel alteration, the test results yield the similar steady-state engine performance in net thrust, air flow, exhaust gas temperature, etc. On the other hand, the fuel consumption of JP-S increased by 5 % compared with that of JP-8. In point of specific fuel consumption (SFC), SFC of JP-S was approximately 1.1~2.6 %, 5 % higher than that of JP-8 in ground and altitude tests respectively at the same thrust.

Study on Aero-derivative Turbo Shaft Engine Development for MGET™ Test Bench

Lahari Sumanth(라하리),Seong Hee Kho(고성희),Ja Young Ki(기자영),Chang Duk Kong(공창덕) 한국추진공학회 2014 한국추진공학회 학술대회논문집 Vol.2014 No.12

MGETTM 테스트 벤치는 추력 140N급의 마이크로 터보 제트 엔진을 이용하여 가스터빈 엔진의 지상성능 시험을 수행할 수 있도록 개발된 교육용 시험장치 이다. 현장 에서 대상 엔진의 다양화가 요구되어 MGETTM 테스트 벤치의 터보 제트 엔진을 터보 축 및 터보 프롭 엔진으로 개조에 대한 연구가 대두 되었다. 상용으로 개발된 마이크로 엔진은 대부분 100~200 N급 터보 제트 엔진이며 일부 제작사만이 터보 프롭 엔진으로 개조하여 제공하고 있고 터보 축 엔진은 상용화 되어 있지 않은 실정이다. 따라서 본사에서는 MGETTM 테스트 벤치에 터보 축 엔진을 사용하기 위해 140 N급의 터보 제트 엔진을 7 ㎾급의 터보 축 엔진으로 개조하는 연구에 착수하였다. 본 논문에서는 개조된 터보 축 엔진의 성능해석 및 기본 설계에 관하여 기술하였다. MGETTM Test bench acquires micro jet engine, of thrust class 140 N. Test bench used for educational purpose, for study of micro jet engine propulsion and its performance. Further developments of MGETTM Test bench is considered to integrate turbo shaft/ turbo prop engines, to study its performance and power offtake. Micro engines which are available commercially of thrust class 100~200 N doesn"t support for additional power offtake, as they designed for full performance usage for thrust generation. And only few OEM" s have turbo prop designs which differ from turboshaft configuration. Thus, we developed power offtake from commercially available micro engines with few modifications. This, paper includes brief study of 7 ㎾ power extraction from 140 N thrust class micro jet engine. Successful concepts with its performance model data and engine modifications details are included.

마이크로 제트엔진 배기노즐 형상변화에 따른 성능특성

박규상(Gyusang Park),최성만(Seongman Choi),김원철(Woncheol Kim) 한국추진공학회 2016 한국추진공학회 학술대회논문집 Vol.2016 No.5

항공기엔진 배기노즐의 형상변화에 따른 성능특성을 이해하기 위하여 마이크로 터보제트 엔진을 이용한 성능실험을 수행하였다. 배기노즐의 형상은 원형 및 가로세로비가 다른 5개의 사각형 노즐을 이용하였다. 연구결과 엔진노즐 형상변화에 따라 추력이 15 % 정도 감소하는 것으로 측정되었으며, 배기가스 온도와 SFC는 약 9 % 정도 상승하는 것으로 측정되었다. Micro jet engine performance test was conducted to understand the engine characteristics of the exhaust nozzle configuration. One circular and five rectangular shape of the exhaust nozzle are used. From the experimental test results, the thrust was decreased about 15 % and SFC and exhaust gas temperature were increased about 9 % as compared with original micro jet engine.