1 / 35

VORTEX RING-LIKE STRUCTURES IN GASOLINE FUEL SPRAYS: MODELLING AND OBSERVATIONS

VORTEX RING-LIKE STRUCTURES IN GASOLINE FUEL SPRAYS: MODELLING AND OBSERVATIONS. Sergei SAZHIN *, Felix KAPLANSKI **, Steven BEGG *, Morgan HEIKAL *

tansy
Download Presentation

VORTEX RING-LIKE STRUCTURES IN GASOLINE FUEL SPRAYS: MODELLING AND OBSERVATIONS

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. VORTEX RING-LIKE STRUCTURES IN GASOLINE FUEL SPRAYS: MODELLING AND OBSERVATIONS Sergei SAZHIN*, Felix KAPLANSKI**, Steven BEGG*, Morgan HEIKAL* *Sir Harry Ricardo Laboratories, Internal Combustion Engines Group, School of Environment and Technology, Faculty of Science and Engineering, University of Brighton, Brighton, BN2 4GJ, UK **Laboratory of Multiphase Physics, Tallinn University of Technology, Tallinn 19086, Estonia

  2. Presentation overview • • VORTEX RING-LIKE STUCTURES IN ENGINES • • VORTEX RING MODELS • • MODELLING VERSUS EXPERIMENTS • • OTHER RECENT RESULTS

  3. VORTEX RING-LIKE STUCTURES IN ENGINES

  4. A typical spray in Diesel engines

  5. Piston crown position Typical vortex ring-like structure in a gasoline fuel spray

  6. Schematic view of vortex ring generator (Gharib et al.,1998 )

  7. Formation stage(Gharib et al.,1998 ) L/D<4 ‘optimal’ ring L/D»4 L/D>4

  8. Gasoline engine injectors Injector A B Fuel injector type Port (PFI) Direct (G-DI) Nominal fuel pressure 3.5 bar 100 bar Fuel temperature 22 °C 22 °C Fuel type Iso-octane (2,2,4 TMP) Iso-octane (2,2,4 TMP) Injection frequency 1 Hz 1 Hz Injection duration 5 ms 2 ms Air pressure 1 bar 1 bar Air temperature 20 °C 20 °C Orifice size 200 μm 250 μm

  9. VORTEX RING-LIKE STRUCTURE IS GASOLINE ENGINE (injector A) ,

  10. Injector axis Vx2 2Ro l r Vx3 Vx1 Spray width Penetration depth x VORTEX RING-LIKE STRUCTURE IS GASOLINE ENGINE (injector B) ,

  11. The region of maximal vorticity ,

  12. VORTEX RING MODELS ,

  13. Schematic view of a vortex ring

  14. Formulation of the problem , ring-to-core radius

  15. Approximatesolution

  16. Velocity of the centroid at r=0 ,

  17. Velocity of the centroid at r=0 ,

  18. Velocity of the centroid at r=0 (short times) , γ ≈ 0.57721566 is the Euler constant, ψ(x) is the di-gamma function

  19. Velocity of the centroid at r=0 (long times) ,

  20. Velocity of the region of maximal vorticity ,

  21. Velocity of the region of maximal vorticity at long times , Θ 3 ~ t-3b

  22. MODELLING VERSUS EXPERIMENTS

  23. Velocity of the region of maximal vorticity ,

  24. Velocity of the region of maximal vorticity ,

  25. Conclusions • A generalised vortex ring model is based on the assumption that the time dependence of the vortex ring thickness ℓ is given by the relation atb, where a is an arbitrary positive number, and 1/4 ≤b ≤ 1/2 is suggested. • The predictions of the model are compared with the results of experimental studies of vortex ring-like structures in gasoline engine-like conditions with a high pressure (100 bar) G-DI injector and a low-pressure (3.5 bar) port fuel injector (PFI). The G-DI results has shown good agreement with the model. In contrast, the agreement of the PFI results with the model has been poor.

  26. OTHER RECENT RESULTS

  27. Rd whenR Transient heating of a semitransparent spherical body • Sazhin, S.S., Krutitskii, P.A., Martynov, S.B., Mason, D., Heikal, M.R., • Sazhina, E.M. (2007) Transient heating of a semitransparent spherical body, Int J Thermal Science, 46(5), 444-457. whenRd<R<Rg

  28. r T r T s s , Rd Rd , Kinetic Hydrodynamic region region j V q x d Rd 1 2 Evaporation of droplets into a background gas: kinetic modelling • Sazhin, S.S., Shishkova, I.N., Kryukov, A.P., Levashov, V.Yu., Heikal, M.R. (2007) Evaporation of droplets into a background gas: kinetic modelling, Int J Heat Mass Transfer, 50, 2675-2691.

  29. Rd whenR Approximate analysis of thermal radiation absorption in fuel droplets whenRd<R<Rg

  30. where θR is the radiation temperature, Rd is the droplet radius, θR can be assumed equal to the external temperature Text in the case of an optically thin gas in the whole domain. The coefficients depend on the range of radii Approximate analysis of thermal radiation absorption in fuel droplets • Sazhin, S.S., Kristyadi T., Abdelghaffar, W.A., Begg, S., Heikal, M.R., Mikhalovsky, S.V., Meikle S.T., Al-Hanbali, O. (2007) Approximate analysis of thermal radiation absorption in fuel droplets, ASME J Heat Transfer, 129, 1246-1255.

  31. X (mm) Vd (m/s) Particle grouping in oscillating flows • . • Sazhin S.S., Shakked, T., Sobolev, V., Katoshevski, D. (2008) Particle grouping in oscillating flows, European J of Mechanics B/Fluids, 27,131-149. • Katoshevski, D., Shakked, T., Sazhin, S.S., Crua, C., Heikal, M.R. (2008) Grouping and trapping of evaporating droplets in an oscillating gas flow, International J of Heat and Fluid Flow,29, 415-426. Velocities are normalised by ω/k, the distance by 1/k and the time by 1/ω

  32. Acknowledgements • The authors are grateful to EPSRC (Project EP/E047912/1)for financial support.

  33. Thank you for your attentionAny comments or suggestionswould be highly appreciated

  34. VORTEX RING-LIKE STRUCTURES IN GASOLINE FUEL SPRAYS: MODELLING AND OBSERVATIONS Sergei SAZHIN*, Felix KAPLANSKI**, Steven BEGG*, Morgan HEIKAL* *Sir Harry Ricardo Laboratories, Internal Combustion Engines Group, School of Environment and Technology, Faculty of Science and Engineering, University of Brighton, Brighton, BN2 4GJ, UK **Laboratory of Multiphase Physics, Tallinn University of Technology, Tallinn 19086, Estonia

More Related