Identification and characterization of steady spray conditions in convergent, single-hole diesel injectors

Peetak Mitra, Katarzyna Matusik, Daniel Duke, Priyesh Srivastava, Koji Yasutomi, Julien Manin, Lyle Pickett, Christopher F. Powell, Marco Arienti, Eli Baldwin, P. K. Senecal, David Schmidt

Research output: Contribution to journalConference articleOther

2 Citations (Scopus)

Abstract

Reduced-order models typically assume that the flow through the injector orifice is quasi-steady. The current study investigates to what extent this assumption is true and what factors may induce large-scale variations. Experimental data were collected from a single-hole metal injector with a smoothly converging hole and from a transparent facsimile. Gas, likely indicating cavitation, was observed in the nozzles. Surface roughness was a potential cause for the cavitation. Computations were employed using two engineering-level Computational Fluid Dynamics (CFD) codes that considered the possibility of cavitation. Neither computational model included these small surface features, and so did not predict internal cavitation. At steady state, it was found that initial conditions were of little consequence, even if they included bubbles within the sac. They however did modify the initial rate of injection by a few microseconds. Though the needle was never stationary, the mass discharge by the nozzle remained constant for most of the injection. The momentum discharge was more sensitive to lower needle lifts than the mass flow rate. An annular jet, that may follow either the needle surface or the sac wall, forms at low needle lift. The presence of this jet corresponds to a loss of momentum through the nozzle exit. The coefficient of area remains remarkably consistent during the early/late needle transient and is an important discovery.

Original languageEnglish
Number of pages17
JournalSAE Technical Papers
Volume2019
Issue numberApril
DOIs
Publication statusPublished - 2 Apr 2019
EventSAE World Congress 2019 - Detroit, United States of America
Duration: 9 Apr 201911 Apr 2019

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