Effect Chain Analysis of Supercritical Fuel Disintegration Processes Using an LES-based Entropy Generation Analysis

ABSTRACT

In this work, a large eddy simulation (LES) technique combined with entropy generation analysis (EGA) is employed in order to investigate the complex physics of fuel injection under supercritical conditions. In particular, physical processes that are relevant for the fuel breakup and mixing are identified and their effects on the overall disintegration process are quantified. Thereby, it turned out that (1) a chain of four consecutive physical processes (shearing, separation, pseudo-boiling, and turbulent mixing) drive the overall jet disintegration, (2) entropy is primarily generated due to thermal energy conversion processes including pseudo-boiling rather than hydrodynamics, and (3) LES technique combined with EGA proved to be a promising approach for effect chain analyses, not only for simple flows, but also for those with complex thermodynamic properties like supercritical fuel injection. Based on these findings, a physical model of the disintegration process of a cryogenic jet flow injected at supercritical conditions is proposed.

KEYWORDS:

• Supercritical fluid flow
• turbulent round jet
• fuel disintegration
• large eddy simulation
• entropy generation
• irreversibility

Acknowledgments

The authors gratefully acknowledge the financial support by the DFG (German Research Council) SFB-TRR 75 and the support of the numerical simulations on the Lichtenberg High Performance Computer (HHLR) at the Technische Universität Darmstadt.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the DFG SFB-TRR 75.