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RISS 인기검색어
- 검색키워드
- 저자 : ( David L. S. Hung ) (검색결과 2 건)
- 무료
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- 유료
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SUPPRESSED PROMPT ATOMIZATION OF FLASHBOILING SPRAY BY ELEVATING INJECTION PRESSURE
( Qinglin Xu ),( Min Xu ),( David L. S. Hung ),( Tianyun Li ),( Xue Dong ) 한국액체미립화학회 2017 한국액체미립화학회 학술강연회 논문집 Vol.2017 No.-
In a direct injection spark ignition (DISI) engine, the mixing time of the fuel with intake air in the cylinder is limited, thus quicker atomization and evaporation are desired. In general, there are two viable ways to promote these processes. One of them is by increasing the injection pressure, which has always been the key technology adopted by automobile manufacturers to improve the engine performance and meet the emission regulations. While high-pressure injection is already applied in most of the DISI engines, it has been reported that further increase of injection pressure is still beneficial on fuel efficiency and emissions reduction. In addition to this, flash-boiling is also regarded as an effective way to improve fuel atomization and evaporation with the potential to reduce fuel consumption and emissions. Existing research on flash-boiling spray mainly focuses on the multi-hole injector. Its plume-to-plume interaction phenomenon, as called “collapse”, has been thoroughly studied. Its benefits on atomization and evaporation have been proved. However, limited work has been done on the flash-boiling spray of a single-hole injector. Its breakup mechanism and movement behavior need to be further studied. Moreover, the study of high pressure gasoline spray beyond 35 MPa is also limited, especially at flash-boiling conditions. The effects of injection pressure on flash-boiling spray is still unrevealed. Therefore, the objective of this work is to study the influence of the superheat degree and injection pressure on the spray penetration and dispersion of a single-hole injector. Results show that in promoting dispersion and reducing penetration of the fuel, the effect of superheat degree was better than that of high injection pressure. In addition, increasing injection pressure of superheated fuel led to the increase in the tip penetration and decrease in the spray width while the injection pressure had opposite effects on subcooled fuel spray.
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Validity Analysis of Spray Model by Comparing Simulated with Measured Spray Liquid and Vapor Phase
( Zhe Sun ),( Xue Dong ),( Peng Yin ),( Tianyun Li ),( David L. S. Hung ),( Min Xu ) 한국액체미립화학회 2017 한국액체미립화학회 학술강연회 논문집 Vol.2017 No.-
Gasoline direct injection (GDI) Engine is proved to be a key technology to save energy and reduce emissions, which improves the overall engine performance. Spray injection affect the fuel-air mixing directly and computational fluid dynamics(CFD)software is utilized to model the macroscopic shape of the spray and the vapor mass. In this paper, the liquid and vapor phase of the spray of a one-hole injector was studied both experimentally and numerically. The structure and concentration distribution of the vapor phase of the spray, vapor mass and spray penetration were measured using laser induced exciplex fluorescence (LIEF) technique in a constant volume chamber. The simulations were performed by the CONVERGE software. Both the spray penetration and Sauter Mean Diameter (SMD) employed in the simulation were calibrated with the in-chamber measurements. The comparison of vapor concentration between the simulated results and the measured results acquired from the chamber suggest that the evaporation model of the single component fuel has significant influence on the simulated results. In addition, an analysis based on the present evaporation model has been made in this study. The results show that the 2-D plane and local line distributions of vapor concentration in simulation do not best match those from the experiments. It is found to get higher vapor concentration in the simulation model, suggesting that the relationship between vapor concentration and evaporation rate should be considered and further verified.
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