Study of the influence of the needle eccentricity on the internal flow in diesel injector nozzles by computational fluid dynamics calculations

Abstract

In the present paper, a computational study has been performed in order to clarify the effects of the needle eccentricity in a real multihole microsac nozzle. This nozzle has been simulated at typical operating conditions of a diesel engine, paying special attention to the internal flow development and cavitation appearance within the discharge orifices. For that purpose, a multiphase flow solver based on a homogeneous equilibrium model with a barotropic equation of state has been used, introducing the turbulence effects by Reynolds-averaged Navier–Stokes methods with a re-normalization group k–ϵ model. The results obtained from this investigation have demonstrated the huge influence of the needle position on the flow characteristics, showing important hole to hole differences.

Keywords:

• diesel injector
• cavitation
• needle eccentricity
• internal flow

2010 AMS Subject Classifications::

• 76M12
• 76T99

Acknowledgements

This work was partly sponsored by ‘Vicerrectorado de Investigación, Desarrollo e Innovación’ of the ‘Universitat Politècnica de València’ in the frame of the project ‘Estudio de la influencia del uso de combustibles alternativos sobre el proceso de inyección mediante GRID computing (FUELGRID)’, and by ‘Ministerio de Ciencia e Innovación’ in the frame of the project ‘Estudio teórico-experimental sobre la influencia del tipo de combustible en los procesos de atomización y evaporación del chorro Diesel (PROFUEL), reference TRA2011–26293. This support is gratefully acknowledged by the authors.

The authors also thank the computer resources and assistance provided by the Universidad de Valencia in the use of the supercomputer ‘Tirant’.