• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 춘계학술대회논문집
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• pp.1010-1015
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• 2002

Over the last few decades, noise has played a major role in the development of aircraft engines. The dominant noise is generated by the wake interactions of fan and downstream stator. Engine inlet and exhaust ducts are being fitted with liner materials that aid in damping fan related noise. In this paper, the radiation of duct internal noise from duct open ends with liners is studies via numerical methods. The linearized Euler's equations in generalized curvilinear coordinates are solved by the DRP scheme. The far field sound pressure levels are computed by the Kirchhoff integration method. Through comparison of sound directivity from bell-mouth duct with and without liners, it is shown that radiation from engine inlet is affected by liner effects or a soft wall boundary condition.

• 오토저널
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• 제5권4호
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• pp.41-46
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• 1983

The influence of inlet air humidity on the flame velocity and combustion of the spark ignition engine were described experimentally by means of the flame velocity measuring apparatus using ion-current. The flame velocity are greatly influenced air fuel ratio and engine speed, and linealy decrease according to the increasing of inlet air humidity. The flame travell curve is very similar to the rate of mass burned and combustion progressive is estimated mostly by only the rate of mass burned curve. The decreasing of the mean flame velocity is about 0.4m/s for increasing of 0.001 specific humidity and we think the reason is mainly decreasing of thermal conductivity.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2006년도 제27회 추계학술대회논문집
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• pp.331-335
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• 2006

초음속 흡입구는 안정한 유동은 설계점에서 얻을 수 있지만, 비행 중 나타나는 비설계점에서는 흔히 버즈라고 불리는 공력 불안정성에 직면하게 된다. 버즈가 일어나는 동안, 흡입구는 흡입구 선단에 큰 충격파 진동이 나타나며 그에 따라 후류에는 압력 섭동이 발생하며 이는 엔진의 성능감소를 야기한다. 본 연구는 버즈의 일반적인 특성을 파악하기 위해 1단 꺽임각을 갖는 외부 압축식 축대칭 흡입구를 이용하여 실험적, 수치적 연구가 수행되었다. 본 연구를 통해 간헐적으로 나타나는 버즈를 관찰할 수 있었고 배압이 증가할수록 버즈가 일어나는 주파수가 커짐을 확인할 수 있었다.

• 한국추진공학회지
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• 제24권6호
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• pp.120-125
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• 2020

한국형발사체 액체로켓엔진의 개발을 위해 나로우주센터에 구축/개발된 엔진 연소 시험설비에서 75톤급 액체 로켓엔진의 연소시험을 수행하였다. 연료온도 271 K 의 탈설계점 연소시험 중 터보펌프 연료입구압력 저하가 발생하여 시험을 중지하였다. 연료의 수분함유량분석, 연료 런탱크 냉각설비를 이용한 냉각시험, 탈수시험을 수행한 결과 해당 현상이 발생한 원인이 연료 내 수분이었다고 결론을 내렸다. 향후 본 논문의 연구에서 도출된 결과를 적용하여 케로신 연료의 수분관리를 하여 액체 로켓엔진 개발시험을 수행할 예정이다.

• 한국자동차공학회논문집
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• 제11권3호
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• pp.99-105
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• 2003

The configuration of intake port is a dominant factor of inlet air flow and mixture formation in an engine. In this study, as an available technology to optimum intake port, the flow box system using resine has been applied. So we presents a methodology for estimating inlet flow characteristics in this paper. This quantified experimental result shows good agreements with visualization data in a cylinder. We obtained the optimal value of swirl ratio and flow coefficient under steady flow rig test for new development of intake port for heavy-duty engine. From this results, the cylinder heat with a good evaluated swirl flow characteristics was developed and adapted for a 11L heavy-duty engine using the liquid phase LPG injection (LPLi) system. This .research expects to clarify major factor that make the intake port efficiently.

• 대한기계학회논문집
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• 제18권9호
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• pp.2413-2422
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• 1994

The effects of compressor design conditions on the off-design performance of a single-shaft gas turbine engine have been studied. Three different geometric design conditions are considered and three different values for the specific mass flow rate at the inlet to the compressor are assumed. For each of nine compressor design, the off-design performance of the gas turbine engine is predicted using the method previously proposed by present authors. Results show that the predicted off-design performances are quite different from each other even though they have the same performance at design point: it means that compressor design conditions should be determined in consideration of the off-design performance of the engine. The specific mass flow rate at the inlet to the compressor is also shown that it might be optimized with respect to the net power of the engine.

• 한국자동차공학회논문집
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• 제6권6호
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• pp.72-79
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• 1998

The goals of this research are to understand the regeneration characteristics in diesel particulate filter(DPF) using the cerium additive and throttling. The effects of throttling duration and spring tension of throttling valve were studied. Measurements were made on a 6 cylinder direct injection diesel engine and included pressure drop, filter inlet temperature, oxygen concentrations, and torque. The major conclusions of this work include; (i) the pressure drop is increased with increase of the engine load and the engine speed; (ii) the inlet temperature of the filter is reached $350^{\circ}C$ with certain engine operating condition which leads to sufficient temperature to regenerate with additive; and (iii) oxygen concentrations in the filter and engine torque during throttling operation are decreased by 2 percent and 36 percent, respectively, which are not critical about regeneration and vehicle operation.

• 한국자동차공학회논문집
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• 제6권4호
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• pp.151-159
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• 1998

The heavy equipment such as tracter has been studied to improve rather the performance of engine than comfort. The mufflers of tracters have various specifications according to their uses. The exact analysis of various mufflers is needed to reduce the level of exhaust moise, a major noise source of engine, to improve the ride quality of tracter. In this study, a software based on Green's function is developed to predict the performance of sound transmission loss for a muffler according to the locations of inlet/outlet pipes. The locations of inlet and outlet pipes can be fixed at different position individually. The conventional muffler has the locations of inlet/outlet pipes on the direction of longitudinal axes. On other hand, the inlet and outlet pipes may be located at the circumferential surface of a test muffler such as one of tracter. The software is verified by analysis and experiment on current muffler of tracter and the improvement technique is proposed to reduce the level of exhaust noise.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1988년도 한국자동제어학술회의논문집(국내학술편); 한국전력공사연수원, 서울; 21-22 Oct. 1988
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• pp.214-218
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• 1988

This paper suggests mathemathical engine model which can simulate generalized gasoline engine. Suggested engine model contains air/fuel inlet element, intake manifold, combustion, engine dynamics. In order to analyze a gasoline engine, physical characteristics of engine and steady state engine data should be controlled. In adaptation for abrupt change of circumstance or drive conditions, this model can analyze important physical phenomena in the intake manifold by computer simulation. This model can also evaluate statuses of drive under various working conditions precisely. Therfore, this model suggests basic datum to evaluate the engine system which are needed in designing and development of engine controller.

• 한국분무공학회지
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• 제22권2호
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• pp.62-68
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• 2017

It is important to study on the combustion instability to develop liquid rocket engines for preventing lower combustion efficiency and destruction of combustion chamber. There are many researches on simplex injector with liquid pulsation to solve this problem. In real rocket engine system, however, they use coaxial injectors. Therefore, research on coaxial injector with liquid pulsation is essential. In this study, we investigate dynamic characteristics of gas centered swirl coaxial injector varying tangential inlet diameter. A mechanical pulsator was used to generate an excitation in the liquid flow, and the response characteristics of the injector were confirmed. As tangential inlet diameter increased, mass flow rates increased and spray angle decreased. As tangential inlet diamter decreased, gain decreased because the pressure fluctuation in the injector manifold rarely passed through the inlet. Additionally, it was confirmed that a sufficiently small tangential inlet served as a damper.