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김태규(Tae-Kyu Kim),이웅건(Woong-Gun Lee),강승천(Sung-Chon Kang),이동인(Dong-In Lee) 한국자동차공학회 2006 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
The major purpose of this study is to find optimized Injector nozzle's hole-number, hole-hyd.flow and injection pressure, injection-timing in order to achieve their NOx reduction targets while minimizing smoke and fuel economy penalty. The tests were performed on a 6 ℓ Common Rail Diesel Engine to use commercial-vehicle, excavator, wheel-loader, fork-lift truck. In this study, two case of injector nozzle's hole-number(#7, #8) and three case of injector nozzle's hole-hyd.flow(Standard, +7%, -7%) were tested for their relation of NOx, BSFC, smoke by changing injection-pressure, injection-timing. From the test, we find that injector nozzle's hole-number, #8 and hole-hyd.flow, Standard are optimized at this engine. And we find engine performance and emission trend by changing injection-pressure and injection-timing.
Numerical study on flow and heat transfer behavior of vortex and film composite cooling
Li Liang,Du Changhe,Chen Xiuxiu,Wang Jiefeng,Fan Xiaojun 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.6
The complete vortex and film composite cooling model is established to study the flow and heat transfer behavior. Influences of coolant Reynolds number, film hole diameter and inject angle on vortex and film composite cooling property are thoroughly discussed. Results show that the vortex nozzle coolant mass flux increases along the vortex chamber axial direction, while the film hole coolant mass flux and blowing ratio decrease along the vortex chamber axial direction. The internal heat transfer intensity will increase along the vortex chamber axial direction. The adiabatic film cooling efficiency decreases downstream due to counter rotating vortex pairs (CRVP) lift off wall effects. The coolant rotational velocity in vortex chamber increases with the increasing Reynolds number, thus leading to obvious heat transfer enhancement. An increase in Reynolds number results in an increase in CVRP intensity, hence the adiabatic film cooling efficiency will turn lower. The coolant rotational velocity and internal heat transfer intensity will decrease with the increase of film hole diameter. The CRVP intensity and film hole jet coolant mass flux increases with the increasing film hole diameter, leading to an increase in adiabatic film cooling efficiency. The rotational coolant flow and heat transfer intensity are not sensitive to inject angle. As the inject angle increases, the CRVP intensity changes little and the inject coolant owns larger inclined angle with gas mainstream flow, therefore the adiabatic film cooling efficiency will increase.
Lee, Sanghoon,Oh, Yunjung,Park, Sungwook SAGE Publications 2013 Proceedings of the Institution of Mechanical Engin Vol.227 No.7
<P>The main objective of this experimental study was to investigate the spray atomization process of a multi-hole gasoline direct injector by characterizing the basic process of single-jet atomization as well as complex phenomena such as air entrainment and jet interactions. We measured the droplet size and velocity using a phase Doppler particle analysis system at different measurement distances and different injection pressures in both the parallel direction and the orthogonal direction with respect to spray propagation. In addition, we calculated the Weber numbers to characterize further the spray atomization process. Our experimental results showed that the droplet velocities followed similar trends for different measurement distances but that the peak value decreased as the distance increased. Furthermore, a leading edge of the spray was observed at the initial stage of injection but disappeared as the measurement distance increased. Based on the droplet diameter distribution, we confirmed that increasing the distance and air entrainment had effects on the jet atomization process. Air entrainment was seen at the edges of both sides of the jet when the droplet diameter was less than 23 µm and the droplet was travelling at a low velocity, and the spray atomization process was more activated under air entrainment conditions. A comparison of different injection pressures confirmed that the injection pressure plays an important role in droplet break-up.</P>
연료온도 및 분사홀 크기에 의한 GDI 인젝터 유량 특성 연구
송재천 ( Song Jae-cheon ),정재호 ( Jung Jae-ho ),박정환 ( Park Jeong-hwan ) 한국액체미립화학회 2018 한국액체미립화학회 학술강연회 논문집 Vol.2018 No.-
This study presents an experimental investigation of the flow characteristics according to fuel temperature and spray hole size for high pressure GDI injector, equipped with multi-hole type nozzle. For this purpose, injection rate measurements were performed with four different spray hole size over operating conditions from 100 to 300bar of fuel pressure and from -30 to +80℃ of fuel temperature. The test was conducted on FIE system bench similar to the actual engine operating conditions using the solenoid type injector.(Fig.1) Fuel injection rate was analyzed by using IAV injection rate system based on the Bosch method.