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Atomization and Sprays

Journal of the International Institutes for Liquid Atomization and Spray Systems

ISSN for PRINT: 1045-5110

Institutional price:	$787.00
Issues per year:	8

Best Paper Award Selection - Editorial Board Site

2008, Volume18

99 pages

Issue price - $118.00

MULTIDIMENSIONAL SIMULATION OF CAVITATING FLOWS IN DIESEL INJECTORS BY A HOMOGENEOUS MIXTURE MODELING APPROACH

Chawki Habchi
IFP, Avenue de Bois-Préau 92852 Rueil-Malmaison Cedex, France

Nicolas Dumont
PSA Peugeot Citroen, 18 rue des Fauvelles 92250 La Garenne Colombes, France

Olivier Simonin
IMF Toulouse, Allée du Professeur Soula 31400 Toulouse, France

ABSTRACT

Because of intense flow recirculations and strong local depression, cavitation occurs in high-pressure Diesel injectors. Because experiments are very difficult to perform for injection conditions (small length and time scales, high-speed flow, etc.), multidimensional modeling seems to be an appropriate tool in order to better understand the flow features inside and at the exit of the injector nozzle. The purpose of this paper is to present the application of the homogeneous equilibrium modeling (HEM) approach for the simulation of cavitating flows inside a Diesel multihole injector. The validation of the model for typical cavitating flow configurations is presented. The HEM approach allows one to reproduce different cavitation regimes observed experimentally. Indeed, numerical results obtained on a simplified injector [7] agree well with experimental visualizations of cavitation and multiple flow fields. Also, the computed steady-state discharge coefficients of a single hole injector are close to the measured values. Furthermore, numerical results reproduce qualitatively the experimental images of cavitation. Finally, computations of cavitating flows in a six-hole narrow-angle Diesel injector, taking into account the needle displacement, are discussed. It is shown that transient injector exit conditions (i.e., fluid velocity at the injector exit, void fraction, cone angle, etc.) are mainly due to the cavitation collapse especially, during the opening and closing of the injector needle. Therefore, transient computational fluid dynamics code boundary conditions have to be taken into account to improve spray atomization and combustion modeling.