Particle Image Velocimetry Flow Measurements and Heat-Release Analysis in a Cross-Flow Cylinder Head

Author(s):  
Fredrik Söderberg ◽  
Bengt Johansson
2002 ◽  
Vol 3 (3) ◽  
pp. 139-155 ◽  
Author(s):  
Y Li ◽  
H Zhao ◽  
Z Peng ◽  
N Ladommatos

Tumble motion in the cylinder of a four-valve spark ignition (SI) engine with a production-type cylinder head was studied using cross-correlation digital particle image velocimetry (PIV). The in-cylinder flow field was measured on three planes: the vertical symmetric plane of the combustion chamber, the vertical plane through centres of the intake and exhaust valves, and a horizontal plane 12 mm below the cylinder head. Ensemble-averaged mean velocity, velocity fluctuation distribution and cyclic variation of the instantaneous velocity field were analysed. Analysis results show that the tumble vortex is formed in the early stage of the compression stroke and distorted in the late stage of the compression stroke. The tumble centre is nearly in the centre of the cylinder when the tumble forms. Then it moves gradually to the underneath of the exhaust valves as the piston moves up. It is found that the cyclic variation of the tumble motion at a tumble ratio of 0.9 is so great that the ensemble-averaged flow characteristics hardly represent any individual cycle flow behaviours. Distribution of the velocity fluctuation field is inhomogeneous during the whole compression process. As the engine speed changes the large-scale flow structure seems to remain unaffected.


PLoS ONE ◽  
2013 ◽  
Vol 8 (11) ◽  
pp. e81198 ◽  
Author(s):  
Elizabeth Antoine ◽  
Cara Buchanan ◽  
Kamel Fezzaa ◽  
Wah-Keat Lee ◽  
M. Nichole Rylander ◽  
...  

Volume 4 ◽  
2004 ◽  
Author(s):  
Dong Liu ◽  
Suresh V. Garimella ◽  
Steve T. Wereley

A non-intrusive diagnostic technique, infrared micro-particle image velocimetry (IR-PIV), is developed for measuring flow fields within MEMS devices with micron-scale resolution. This technique capitalizes on the transparency of silicon in the infrared region, and overcomes the limitation posed by the lack of optical access with visible light to sub-surface flow in silicon-based micro-structures. Experiments with laminar flow of water in a circular micro-capillary tube of hydraulic diameter 255 μm demonstrate the efficacy of this technique. The experimental measurements agree very well with velocity profiles predicted from laminar theory. Cross-correlation and auto-correlation algorithms are employed to measure very-low and moderate-to-high velocities, respectively; the former approach is suitable for biomedical applications while the latter would be needed for measurements in electronics cooling. The results indicate that the IR-PIV technique effectively extends the application of regular micro-PIV techniques, and has great potential for flow measurements in silicon-based microdevices.


2006 ◽  
Author(s):  
Kenichi Watanabe ◽  
Tomonori Nakatsuka ◽  
Daichi Suzuki ◽  
Takashi Nagumo ◽  
Masahiro Motosuke ◽  
...  

Recent development of micro devices is remarkable as in the examples of Micro-TAS, Lab-on-a-chip or ultra micro gas turbine. In order to make the micro devices smaller and more effective, an appropriate use of a micro scale jet as an actuator can be a key technology. Aiming at the development of a measurement system of the micro flow control devices in the future micro aerodynamics, we have established a system to measure a continuous jet, a pulsed jet and a synthetic jet for the flow control in the low Reynolds number air flow with a micro length scale. The two-dimensional flow field around the micro jet using micro particle image velocimetry (PIV) was measured. The jet was injected through the device using an acoustic speaker. It was observed that a saddle point existed at the certain phase where the velocity is 0 at the boundary of the jet blowing and suction phase for the synthetic jet into a still air. It was found that the pulsed jet and the synthetic jet are more effective in the fluid mixing in the low Reynolds number flow than the continuous jet. The dead water region was observed downstream of the jet in case of the jet injection into cross flow. It was recognized that the synthetic jet at the certain oscillation frequency generated a vortex pair near the jet hole.


1996 ◽  
Vol 7 (9) ◽  
pp. 1270-1280 ◽  
Author(s):  
M L Jakobsen ◽  
W J Easson ◽  
C A Greated ◽  
D H Glass

Author(s):  
Masaki Hiratsuka ◽  
Shinichiro Ito ◽  
Keita Miyasaka ◽  
Akihisa Konno

A knuckle shot, resulting from non-spinning kicking, is an essential technique in soccer. The irregular flight path of the knuckle shot is caused by the aerodynamic force from the three-dimensional twin vortices generated in the wake behind the ball. However, the detailed behavior of the twin vortices and relation between the jet flow and the acting forces on the balls is still not understood. In addition, a more thorough understanding of the effect of ball panels on the formation of twin vortices and jet flow is important to develop balls with high controllability. To study the effect of the ball panel shape on the flight path, stereo three-dimensional particle image velocimetry wake flow measurements and synchronized force measurements were performed on various soccer balls. It was confirmed that the aerodynamic force on the ball is produced by the jet flow generated by the vortices in the wake flow. The directions of the force followed the changes of the jet flow, and the magnitude of the force was strongly associated with the flow rate of the jet. Moreover, the shape of the ball panels, especially the groove volume, determines the critical Reynolds number and the fluttering of the balls.


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