کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
652658 | 885035 | 2008 | 12 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
In-cylinder flows of a motored four-stroke engine with flat-crown and slightly concave-crown pistons
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موضوعات مرتبط
مهندسی و علوم پایه
مهندسی شیمی
جریان سیال و فرایندهای انتقال
پیش نمایش صفحه اول مقاله
![عکس صفحه اول مقاله: In-cylinder flows of a motored four-stroke engine with flat-crown and slightly concave-crown pistons In-cylinder flows of a motored four-stroke engine with flat-crown and slightly concave-crown pistons](/preview/png/652658.png)
چکیده انگلیسی
The temporal and spatial evolution processes of the in-cylinder flow structures and turbulence intensities in the symmetry and offset planes of a motored four-valve, four-stroke engine during the intake and compression strokes are diagnosed by using a particle image velocimeter. Two pistons of different crown shapes (flat-crown and slightly concave-crown pistons) are studied. The inception, establishment, and evolution of the tumbling vortical flow structures during the intake and compression strokes are clearly depicted. Quantitative strengths of the rotating vortical flow motions are presented by a dimensionless parameter, the tumble ratio, which can represent the mean angular velocity of the vortices in the target plane. The turbulence intensity of the in-cylinder flow is also calculated by using the measured time-varying velocity data. The results show that the flat-crown piston induces higher bulk-averaged tumble ratio and turbulence intensity than the slightly concave-crown piston does because the tumble ratio and turbulence generated by the flat-crown piston in the offset planes during the compression stroke are particularly large. The engine with the flat-crown piston also presents larger torque and power outputs and lower hydrocarbon emission than that with the slightly concave-crown piston. This might be caused by the enhanced combustion in the engine cylinder due to the stronger tumble ratio and turbulence intensity.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Experimental Thermal and Fluid Science - Volume 32, Issue 5, April 2008, Pages 1156-1167
Journal: Experimental Thermal and Fluid Science - Volume 32, Issue 5, April 2008, Pages 1156-1167
نویسندگان
R.F. Huang, H.S. Yang, C.-N. Yeh,