Flash-boiling of sprays may occur when a superheated liquid is discharged into an ambient environment with lower pressure than its saturation pressure. Such conditions normally exist in direct-injection spark-ignition engines operating at low in-cylinder pressures and/or high fuel temperatures. The addition of novel high volatile additives/fuels may also promote flash-boiling. Fuel flashing plays a significant role in mixture formation by promoting faster breakup and higher fuel evaporation rates compared to non-flashing conditions. Therefore, fundamental understanding of the characteristics of flashing sprays is necessary for the development of more efficient mixture formation. The present computational work focuses on modelling flash-boiling of n-Pentane and iso-Octane sprays using a Lagrangian particle tracking technique. First an evaporation model for superheated droplets is implemented within the computational framework of STAR-CD, along with a full set of temperature dependent fuel properties. Then the computational tool is used to model the injection of flashing sprays through a six-hole asymmetric injector. The computational results are validated against optical experimental data obtained previously with the same injector by high-speed imaging techniques. The effects of ambient pressure (0.5 and 1.0 bar) and fuel temperature (20-180° C) on the non-flashing and flashing characteristics are examined. Effects of initial droplet size and break-up sub-models are also investigated. The computational methodology is able to reproduce important physical characteristics of flash-boiling sprays like the onset and extent of spray collapse. Based on the current observations, further improvements to the mathematical methodology used for the flash-boiling model are proposed.


    Zugriff

    Zugriff prüfen

    Verfügbarkeit in meiner Bibliothek prüfen

    Bestellung bei Subito €


    Exportieren, teilen und zitieren



    Titel :

    Aspects of Numerical Modelling of Flash-Boiling Fuel Sprays


    Weitere Titelangaben:

    Sae Technical Papers


    Beteiligte:

    Kongress:

    12th International Conference on Engines & Vehicles ; 2015



    Erscheinungsdatum :

    2015-09-06




    Medientyp :

    Aufsatz (Konferenz)


    Format :

    Print


    Sprache :

    Englisch




    Experimental Study on Flash Boiling of Ammonia Fuel Sprays – A Potential Alternative Fuel

    Larmi, Martti / Yeganeh, Maryam / Akram, Muhammad Saad et al. | SAE Technical Papers | 2023


    Novel methods for 3D-CFD simulation of flash-boiling and multi-component fuel sprays

    Lucas, Gwendal / Technische Universität Braunschweig / Shaker Verlag | TIBKAT | 2018



    Flash boiling effects in the development of gasoline direct-injection engine sprays

    Schmitz,I. / Ipp,W. / Leipertz,A. et al. | Kraftfahrwesen | 2002


    Flash Boiling Effects on the Development of Gasoline Direct-Injection Engine Sprays

    Leipertz, Alfred / Schmitz, Ingo / Ipp, Wolfgang | SAE Technical Papers | 2002