Experimental instantaneous shadowgraph visualizations on transparent glass nozzle replicas of high-pressure fuel injectors have been used to validate a novel in-house high-fidelity LES-VOF multiphase solver, to study the evolution of vortex flow and fuel cavitation. Both experiments and simulations capture the formation of an unsteady vapor structure inside the nozzle volume, which is referred to as ‘string-cavitation’; strings are found at the core of the recirculation zones. High-fidelity simulations provide a very detailed insight into the vortex generation in the injector nozzle; strings appear within the time scales that are relevant for fast injection events (on the order of 0.1 milliseconds) and, for the problem under consideration, their generation seems mostly related to the flow pattern in the sac. It is also shown that vortexes interact, merge till they disrupt and favor the temporary inception of shear cavitation.

Vortex Flow and Cavitation in Liquid Injection: a Comparison between High-Fidelity CFD Simulations and Experimental Visualizations on Transparent Nozzle Replicas

Piscaglia, F.;
2021-01-01

Abstract

Experimental instantaneous shadowgraph visualizations on transparent glass nozzle replicas of high-pressure fuel injectors have been used to validate a novel in-house high-fidelity LES-VOF multiphase solver, to study the evolution of vortex flow and fuel cavitation. Both experiments and simulations capture the formation of an unsteady vapor structure inside the nozzle volume, which is referred to as ‘string-cavitation’; strings are found at the core of the recirculation zones. High-fidelity simulations provide a very detailed insight into the vortex generation in the injector nozzle; strings appear within the time scales that are relevant for fast injection events (on the order of 0.1 milliseconds) and, for the problem under consideration, their generation seems mostly related to the flow pattern in the sac. It is also shown that vortexes interact, merge till they disrupt and favor the temporary inception of shear cavitation.
2021
3-phase LES-VOF solver; cavitation; CFD of internal nozzle flows; LibPoliMi/DAER; liquid injection; OpenFOAM; primary atomization
File in questo prodotto:
File Dimensione Formato  
PISCF_OA_01-21.pdf

Open Access dal 19/02/2023

Descrizione: Paper Open Access
: Post-Print (DRAFT o Author’s Accepted Manuscript-AAM)
Dimensione 21.46 MB
Formato Adobe PDF
21.46 MB Adobe PDF Visualizza/Apri
PISCF01-21.pdf

Accesso riservato

Descrizione: Paper
: Publisher’s version
Dimensione 6.52 MB
Formato Adobe PDF
6.52 MB Adobe PDF   Visualizza/Apri

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11311/1161852
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 17
  • ???jsp.display-item.citation.isi??? 11
social impact