Compared with port fuel injection engines, direct injection (DI) gasoline engine is becoming the
mainstream of gasoline engines because of its higher fuel economy and excellent transient response. It has been
proven that fuel spray characteristics in DI engines are crucial to the performance and emission quality of the
engine. Flash boiling spray has great potential to achieve high fuel economy and low emission by dramatically
improving the fuel atomization and vaporization and it has different spray-air interaction behavior as compared
with non-flash boiling one, while its mechanism is more complex as compared with subcooled spray. We investigate
the time-resolved spatial velocity field of the spray using 2-camera high-speed 3D3C (3-dimension 3-component)
tomographic particle image velocimetry (PIV) diagnostic technique. A 10mm thick laser sheet is used to illuminate
the fuel spray. Characteristics of both non-flash and flash boiling sprays are studied. A single-hole injector is
mounted within a heat exchanger so that different fuel temperature can be accessed. In the experiment, n-pentane
is used as the fuel. For the non-flash boiling spray, the velocity field of the liquid spray is mostly consistent to
the injection direction. With the increase of the degree of superheat (DoS), the overall velocity scale decreases
especially at the spray tip. Meanwhile, larger swirls occur at the lower part of the flash boiling spray, which means
stronger spray-air interaction occurs at a higher DoS.
XU Hongchang (徐宏昌), LIU Shuangzhai (刘双寨), PAN Haoxing (潘浩星)
. Spray Characteristics with High-Speed Tomographic Particle Image Velocimetry Under Non-Flash and Flash Boiling Conditions[J]. Journal of Shanghai Jiaotong University(Science), 2019
, 24(5)
: 591
-596
.
DOI: 10.1007/s12204-019-2118-y
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