Journal of Shanghai Jiao Tong University (Science) ›› 2019, Vol. 24 ›› Issue (5): 591-596.doi: 10.1007/s12204-019-2118-y

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Spray Characteristics with High-Speed Tomographic Particle Image Velocimetry Under Non-Flash and Flash Boiling Conditions

XU Hongchang (徐宏昌), LIU Shuangzhai (刘双寨), PAN Haoxing (潘浩星)   

  1. (National Engineering Laboratory for Automotive Electronics Control Technology, Shanghai Jiao Tong University, Shanghai 200240, China)
  • 出版日期:2019-10-08 发布日期:2019-09-27
  • 通讯作者: LIU Shuangzhai (刘双寨) E-mail:Shuangzhailiu@sjtu.edu.cn

Spray Characteristics with High-Speed Tomographic Particle Image Velocimetry Under Non-Flash and Flash Boiling Conditions

XU Hongchang (徐宏昌), LIU Shuangzhai (刘双寨), PAN Haoxing (潘浩星)   

  1. (National Engineering Laboratory for Automotive Electronics Control Technology, Shanghai Jiao Tong University, Shanghai 200240, China)
  • Online:2019-10-08 Published:2019-09-27
  • Contact: LIU Shuangzhai (刘双寨) E-mail:Shuangzhailiu@sjtu.edu.cn

摘要: 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.

关键词: tomographic particle image velocimetry (PIV), velocity field, non-flash boiling spray, flash boiling spray, degree of superheat (DoS)

Abstract: 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.

Key words: tomographic particle image velocimetry (PIV), velocity field, non-flash boiling spray, flash boiling spray, degree of superheat (DoS)

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