The analysis of multi-phase jets and mixing zones

  • Sazhin, Sergei (PI)
  • Osiptsov, Alexander (CoPI)
  • Heikal, Morgan (CoI)
  • Healey, Jonathan (CoI)

Project Details

Description

This project in 2012 was based on a Royal Academy of Engineering grant and continued work that had been supported through earlier EPSRC grants. It provided for the visit of the internationally leading scholar in the field, Professor Alexander Osiptsov, from Moscow State University as a Distinguished Visiting Fellow.

This opportunity was developed and supported by nine former EPSRC grants, including a grant for a project entitled ‘Modelling of breakup processes in transient Diesel fuel sprays’. This project focused on the modelling of jet primary break-up via the stability analysis of transient jets with results presented in research papers published in the Journal of Fluid Mechanics and in Physics of Fluids.

At the time an almost universal approach to engineering modelling was based on using commercial software packages which employed standard mathematical models. In addition to these packages, in-house numerical codes had been developed which were based on numerical solutions of the underlying partial or ordinary differential equations. The modelling group at the Sir Harry Ricardo Laboratory at the University of Brighton had developed a novel approach to engineering modelling, focused on the analysis of underlying physics of the phenomena and applying combined analytical/asymptotic and numerical techniques. 

The main limitation of the models developed in these papers was that they were based on the assumption that the jets and surrounding gas are single-phase media. In real situations, however, bubbles of air were almost always present inside jets and droplets were entrained in the surrounding air. This led researchers to the necessity of the analysis of multi-phase jets and mixing zones. Professor A.N. Osiptsov had become one of the world leaders in disperse-mixture modelling and the stability analysis of multi-phase flows.

One of the methods which Osiptsov developed for the analysis of these flows was widely known as the Osiptsov Lagrangian method (this term is widely used in fluid dynamics community: e.g. Healy, D.P, Young, J.P, 2001, Calculation of inertial particle transport using the Osiptsov Lagrangian method, 4th Int Conf. Pn Multiphase Flow, New Orleans, Paper DJ4). The method proved an efficient tool for studying disperse flows with local particle accumulation regions and intersecting particle trajectories.

The research programme for Professor Osiptsov’s visit focused on the applicability of the models and numerical methods of multiphase-flow hydrodynamics, developed by him and his colleagues, including the problems of hydrodynamic stability of sprays observed in automotive applications.

This work during the visit contained the following activities:

Identification of a specific engineering problem, referring to the modelling of spray primary break-up, for the solution of which the Osiptsov Lagrangian method could be applied. 

Discussion of long term collaborative programmes leading to an EPSRC grant application focused on the formation and dynamics of automotive sprays. At the time, nobody had attempted to use the Osiptsov Lagrangian method for studying dispersed systems with phase changes, and to apply the multiphase stability theory to modelling spray formation and dynamics. Participants in the facilitated discussions included Professor M Heikal (Head of Automotive Engineering Research at the University of Brighton), Ricardo Consulting Engineers and Professor J Healey, from Keele University who had been a collaborator on the foundational EPSRC projects.

Professor Osiptsov delivered seminars for staff and students at the School of Computing, Engineering and Mathematics at the University of Brighton, and the Department of Mathematics at Keele University. This, together with research discussions with staff and students, led to other possible collaborative programmes where the new approach was applicable. 
StatusFinished
Effective start/end date1/01/1228/02/12

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