Large-eddy simulation of cavitating nozzle and jet flows

F Örley,M S Mihatsch,S Hickel,N A Adams,T Trummler,S J Schmidt

doi:10.1088/1742-6596/656/1/012096

F Örley, M S Mihatsch + Show 4 more

Open Access

https://doi.org/10.1088/1742-6596/656/1/012096

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Abstract

We present implicit large-eddy simulations (LES) to study the primary breakup of cavitating liquid jets. The considered configuration, which consists of a rectangular nozzle geometry, adopts the setup of a reference experiment for validation. The setup is a generic reproduction of a scaled-up automotive fuel injector. Modelling of all components (i.e. gas, liquid, and vapor) is based on a barotropic two-fluid two-phase model and employs a homogenous mixture approach. The cavitating liquid model assumes thermodynamic- equilibrium. Compressibility of all phases is considered in order to capture pressure wave dynamics of collapse events. Since development of cavitation significantly affects jet break-up characteristics, we study three different operating points. We identify three main mechanisms which induce primary jet break-up: amplification of turbulent fluctuations, gas entrainment, and collapse events near the liquid-gas interface.

Highlights

Modern fuel injection systems play a key role for the optimization of the air-fuel mixing process in the combustion chamber
Sou et al [1, 2] assume that primary break-up of liquid jets is promoted by enhanced turbulent fluctuations caused by collapse events of cavitation structures near the nozzle outlet
Numerical Method We employ an implicit large-eddy simulations (LES) approach based on the Adaptive Local Deconvolution Method (ALDM) by Adams et al [6] and Hickel et al [7, 8]

Summary

Introduction

Modern fuel injection systems play a key role for the optimization of the air-fuel mixing process in the combustion chamber. The collapse of vapor pockets in regions of higher pressure causes strong shock-waves and highvelocity liquid jets directed towards the wall surface. Cavitation can lead to choked conditions in a duct and maintains a mass flow rate independent of the pressure-drop.

Results

Conclusion