• Title/Summary/Keyword: 흡입구 형상

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Development of Icing Simulation Device for Gas Turbine Icing Test (가스터빈 결빙시험용 결빙모사장치 개발)

  • Lee, Kyung-Jae;Yang, Soo-Seok;Lee, Dae-Sung
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2007.04a
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    • pp.358-361
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    • 2007
  • Most aircraft cruise in the stratosphere at which temperature is below $-50^{\circ}C$ md, as a result, the surface of aircraft can be iced up. Ice on the wing can change aerodynamic characteristic and results in the deterioration of its performance. Ice on the engine inlet increases the possibility of compressor blade damage and affects the performance and safety of the engine. This paper focused on the development of icing simulation device for analyzing effect of icing on engine performance. Icing simulation tests were conducted with a liquid air system and a icing simulation device and results show that icing could be simulated with this system.

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Development of Icing Simulation Device for Gas Turbine Icing Test (가스터빈 결빙시험용 결빙모사장치 개발)

  • Lee, Gyeong-Jae;Lee, Jin-Geun;Go, Seong-Hui;Jeon, Yong-Min;Yang, Su-Seok;Lee, Dae-Seong
    • Aerospace Engineering and Technology
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    • v.5 no.2
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    • pp.37-46
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    • 2006
  • The outside environment is very severe while aircraft is cruising. Especially small particle of icing in cold air condition can have negative influence on aircraft performance. If ice particle is attached to leading edge of wing, it can change wing configuration and decrease flight quality. If icing particle is attached to inlet of engine, it can damage compressor blade and have negative influence to aircraft safety. We make icing simulation device with liquid air system for analyzing about variation of engine performance due to incoming of icing to engine.

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Scramjet Experimental Techniques Using a Shock Tunnel (충격파 터널을 이용한 스크램제트 실험 기술)

  • Yang, Sungmo;Kim, Keunyeong;Chang, Eric Won Keun;Jin, Sangwook;Park, Gisu
    • Journal of the Korean Society of Propulsion Engineers
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    • v.22 no.5
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    • pp.97-106
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    • 2018
  • This paper summarizes the technical difficulties pertaining the double-compression ramp scramjet inlet model testing in a shock tunnel and their corresponding solutions. Four technical difficulties are identified: 1) test facility unstart, 2) flow disturbance and model damage due to the impact of diaphragm debris, 3) lack of fuel jet development due to multiple injection, and 4) short test time. After overcoming the identified technical difficulties, the improved results were confirmed through the results of shadowgraph images and shock tube end wall pressure.

Effects of IR Reduction Design on RCS of UCAV (IR 저감 설계가 무인전투기의 RCS에 미치는 영향)

  • Song, Dong-Geon;Yang, Byeong-Ju;Myong, Rho-Shin
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.46 no.4
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    • pp.297-305
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    • 2018
  • The role of UCAV is to carry out various missions in hostile situations such as penetration and attack on the enemy territory. To this end, application of RF stealth technology is indispensable so as not to be caught by enemy radar. The X-47B UCAV with blended wing body configuration is a representative aircraft in which modern RCS reduction schemes are heavily applied. In this study, a model UCAV was first designed based on the X-47B platform and then an extensive RCS analysis was conducted to the model UCAV in the high-frequency regime using the Ray Launching Geometrical Optics (RL-GO) method. In particular, the effects of configuration of UCAV considering IR reduction on RCS were investigated. Finally, the effects of RAM optimized for the air intake of the model UCAV were analyzed.

Papers : A Study on the Characteristics of the Ramjet Engine Combustor using a Two Color PIV Technique (논문 : Two Color PIV 기법을 이용한 램제트엔진 연소기 특성에 대한 연구)

  • An,Gyu-Bok;Yun,Yeong-Bin;Jeong,In-Seok;Heo,Hwan-Il
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.30 no.1
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    • pp.95-104
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    • 2002
  • A two color PIV technique has been developed for visualization of complex and high speed flow in a ramjet combustor. Two color PIV has the advantages that velocity distribytions in high speed flowfields can be measured simply by varying the time interval between two different laser beams and a directional ambiguity problem can be solved by color separation, and then a singnal-to-noise ratio can be increased through nearly perfect cross-correlation. As a basic research of the ramjet engine, a 2-D shaped combustor with two symmetric air intakes has been manufactured and an experimental study has been conducted using a two color PIV technique. The flow characteristics such as recirculation zones and two intake air mixing have been investigated varying inlet angles and dome heights. It is found that the size and air mass ratio of reciculation zones are affected mainly by an inlet angle, but not much by a dome height.

터보펌프용 1.4MW급 터빈의 전산유동해석

  • Park, Pyun-Goo;Jeong, Eun-Hwan;Kim, Jin-Han
    • Aerospace Engineering and Technology
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    • v.4 no.2
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    • pp.153-162
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    • 2005
  • Through a preliminary design process, four design candidates for a 1.4MW class partial admission turbine have been chosen and the numerical analyses using a frozen rotor method are applied to estimate their performance. Each flow analysis result was compared with others and the optimum design was selected. Flow characteristics in the passages and some types of losses induced by shocks and wakes were found from calculation results. A new rotor blade was redesigned based on these calculations and this result is compared with previous one through flow analysis.

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Numerical Investigation of the Effect of Turbine flow Passage Variation on the Turbine Performance (유로형상변화에 따른 터빈성능 변화의 수치적 해석)

  • Park, Pyun-Goo;Jeong, Eun-Hwan;Kim, Jin-Han
    • 유체기계공업학회:학술대회논문집
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    • 2005.12a
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    • pp.481-487
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    • 2005
  • A turbopump turbine consists of rotational part including a rotor and stationary part including nozzles and exit guide vanes, of which shape and relative position affect turbine performance owing to supersonic flows with prevailing unsteadiness. In this study, numerical 3-D flow calculations of the turbine with the different number of exit guide vanes and different relative position of each component are conducted and the effect of flow passage variations on turbine performance is analyzed.

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Effect of Shape of Discharge Port on Hydraulic Performance of Automotive Closed Type Water Pump (자동차 밀폐형 워터펌프의 토출구 형상이 수력성능에 미치는 영향)

  • Heo, Hyung-Seok;Lee, Gee-Soo;Bae, Suk-Jung
    • Transactions of the Korean Society of Automotive Engineers
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    • v.14 no.1
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    • pp.39-47
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    • 2006
  • Recent trend in pursuit of high performance and effectiveness for automotive cooling system has changed the application of material for impeller of automotive water pump from metal to high ability engineering resin, which can achieve optimization of design of impeller geometry and realize lightweight high efficiency water pump. Closed type water pump improves hydraulic loss of fluid through the clearance between volute casing and impeller compared with that of the existing open type water pump(Although closed type is heavier than open type for the same size and same material, adoption of plastics can solve the problem.). In the present study, the characteristics of hydraulic performance of closed type water pump were investigated with respect to the angle between shroud and hub of impeller and the shape of discharge port of volute casing. Performance tests were carried out for 4 cases, that is, for 2 impellers and 2 casings. The modification of shape of only discharge port can enhance the hydraulic performance by 10 percent and the pump efficiency by 4-6 percent.

Ramjet Mode Combustion Test for a Dual-Mode Ramjet Engine Model with a Large Backward-Facing Step (큰 후향 계단이 있는 이중 모드 램젯 엔진 모델의 램젯 모드 연소 시험)

  • Yang, Inyoung;Lee, Kyung-jae;Lee, Yang-ji;Kim, Chun-taek
    • Journal of the Korean Society of Propulsion Engineers
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    • v.20 no.6
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    • pp.83-90
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    • 2016
  • Ramjet mode combustion test was performed for a dual-mode ramjet engine model. The engine model consists of an air intake, a combustor and a nozzle. The combustor in the model has a large backward-facing step, designed to be used as a part of a rocket-based combined cycle engine. The test was performed at the flight speed of Mach 5 and the altitude of 24 km. Strong combustion was established only when the fuel was injected from both of the bottom-side and cowl-side wall. When the total fuel stoichiometric ratio was 1.0, distributed as 0.5 on the cowl side and 0.5 on the bottom side, the flow became subsonic at some portion in the combustor by thermal choking, i.e., ramjet mode was established for this condition.

An Analysis of Internal & External Acoustic Fields by Using FEM (유한요소법을 이용한 내부 및 외부 음향장 해석)

  • 이덕주;이재규
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 1992.10a
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    • pp.113-116
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    • 1992
  • 소음의 발생 원인은 공기역학적 측면과 구조적 측면으로 나누어지는데, 실제 로는 유동장에서 발생되는 음원과 구조물에서 발생되는 진동과의 상호 간섭 에 의해 보다 복잡한 형태로 발생된다. 음장 문제를 두가지 범주로 구분하면 첫째는 음원과 구조물과의 상호교란에 의한 산란문제(Scattering)와 둘째로 구조물의 자체 진동에 의한 음의 전파현상과 구조물내부에 회전체와 같은 음원이 존재하는 경우에 음의 전파를 관측하는 방사문제(Radiation)가 있다. 실제로 산업용 터빈이나 비행기 엔진 흡입구에서 발생되는 소음, 또는 자동 차의 배기구를 통해 발생되는 소음 그리고 엔진의 진동에 의한 구조적 소음, 기타 가전제품의 회전체(Fan & Motor)에 의한 소음은 방사(Radiation)의 문 제로서 중요 관심 과제이다 수치적 기법으로 근래에 많이 사용하는 방법으 로 BEM(경계요소법), FEM(유한요소법), FDM(유한차분법)이 있는데 본 연 구에서는 유한요소법을 이용하기로 한다. 지금까지는 주로 BEM을 통해서 Far-Field의 음향장을 해석하였지만 복잡한 형상을 갖는 구조물내부에서의 음향장 변화나 구조물 내부에 음원이 존재하는 경우 또는 구조물 자체가 갖 는 물리적 특성치 변화 즉 물체표면에서의 부분 진동문제의 음향장 해석에 있어서 가장 잘 대체해 나갈 수 있는 방법이 유한 요소법이라고 여겨진다. 본 연구에서는 2차원 또는 기하학적으로 축대칭인 3차원 Duct내부에 음원이 존재하는 경우 음원전파에 따른 Near-field와 far-field에서 음의 방향성을 예측하기 위해 먼저 기본적인 유한요소법에 의한 Robin 경계조건을 사용하 여 계산된 결과와 Infinite Element를 도입하여 계산할 결과를 비교하여, Infinite Element가 보다 효율적이며 타당한 결과를 얻음을 확인해 보기로 한다.다 복합적인 측면에서 치료에 임하여야 할 것으로 사료된다. with such configuration.trap with 2.88[eV] deep of injected space charge from the chathode in the crystaline regions. The origin of ${\alpha}$$_2$ peak was regarded as the detrapping process of ions trapped with 0.9[eV] deep originated from impurity-ion remained in the specimen during production process of the material, in the crystalline regions. The origin of ${\beta}$ peak was concluded to be due to the depolarization process of "C=0"dipole with the activation energy of 0.75[eV] in the amorphous regions. The origin of ${\gamma}$ peak was responsible to the process combined with the depolarization of "CH$_3$", chain segment, with the activation energy of carriers from the shallow trap with 0.4[eV], in he amorphous regions.의 증발산율은 우기의 기상자료를 이용하여 구한 결과 0.05 - 0.10 mm/hr 의 범위로서 이로 인한 강우손실량은 큰 의미가 없음을 알았다.재발이 나타난 3례의 환자

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