A fuel spray induced vortex ring

It is demonstrated that a typical gasoline fuel injection process can be ac companied by the development of a fountain structure consisting of a spray jet and a vortex ring. In the case of a typical injection process lasting 3 ms, the vortex-like structures were observed starting t approximate to 2 m s after the start of injection and lasting until about t = 4.5 ms. The vort ex ring moved in the direction of the jet and its distance from the axis of the spray increased with time. The axial spray velocity initially increase d with increasing distance from the axis, then subsequently decreased. The observed velocity of the vortex ring and the proportionality of its radius and axial displacement are shown to be consistent with the concept of a tim e dependent turbulent eddy viscosity. (C) 2001 Elsevier Science Ltd. All ri ghts reserved.