Title: High-speed impact of micron-sized diesel drop trains—Splashing dynamics, secondary droplet formation, and effects of pre-existing film thickness

Abstract

This work investigates surface impingement of monodispersed diesel drop trains using computational simulations. The three-dimensional simulations include high-speed impact of micrometer-sized fuel drops onto initially dry and wetted stainless steel substrates. The drop size and impact velocity are representative of fuel injection conditions in internal combustion engines (ICEs). The drop trains serve as a simplified representation of fuel spray. To accurately capture the film that naturally develops on initially dry substrates, a dynamic diesel-stainless steel contact angle model was developed using experiments of single drop impact under ICE representative temperature. Simulations are presented for a highly splashing case and the effects of a pre-existing film on splashing dynamics were investigated, including the temporal evolution of splashed mass and film thickness. It was concluded that for thin films, the effect of pre-existing film thickness is less significant than in single drop impingement. Secondary droplet characterization was performed on simulation results, leading to instantaneous and time-averaged distributions of secondary droplet size, velocity magnitude, and trajectory angle. It was found that for each drop impingement, approximately 58% of the splashed mass is from the impinging drop itself, while the remainder of the splashed mass is composed of film liquid. From a high resolutionmore » case, details of secondary droplet formation are observed and three distinct phases of secondary droplet formation are identified. The detailed analysis of drop train impingement under engine-relevant conditions serves as a first step toward a robust understanding of fuel impingement and the development of cleaner and more efficient ICEs.« less

Authors:

Markt, D.  ^[1];

• Search DOE PAGES for author "Markt, D."
• Search DOE PAGES for ORCID "0000-0003-3148-7627"

Raessi, M.  ^[1];

• Search DOE PAGES for author "Raessi, M."
• Search DOE PAGES for ORCID "0000-0001-5415-357X"

Lee, S. -Y.  ^[2];

• Search DOE PAGES for author "Lee, S. -Y."
• Search DOE PAGES for ORCID "0000-0002-5970-370X"

Zhu, X.  ^[2]

• Search DOE PAGES for author "Zhu, X."
• Search DOE PAGES for ORCID "0000-0002-4445-4843"

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+ Show Author Affiliations

1. University of Massachusetts, Dartmouth, MA (United States)
2. Michigan Technological University, Houghton, MI (United States)

Publication Date:

Tue Oct 26 00:00:00 EDT 2021

Research Org.:

Michigan Technological Univ., Houghton, MI (United States); University of Massachusetts, Dartmouth, MA (United States)

Sponsoring Org.:

USDOE Office of Energy Efficiency and Renewable Energy (EERE); Department of Defense (DoD); US Department of the Navy, Office of Naval Research (ONR); National Science Foundation (NSF)

OSTI Identifier:

1978970

Alternate Identifier(s):

OSTI ID: 1827761

Grant/Contract Number:  

EE0007292; N00014-18-1-2255; ENG170004; ENG170008; EE007292

Resource Type:

Accepted Manuscript

Journal Name:

Physics of Fluids

Additional Journal Information:

Journal Volume: 33; Journal Issue: 10; Journal ID: ISSN 1070-6631

Publisher:

American Institute of Physics (AIP)

Country of Publication:

United States

Language:

English

Subject:

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; combustion engine; thin films; computational methods; liquid solid interfaces; computational fluid dynamics; drop breakup; drop formation; flow instabilities; interfacial flows; multiphase flows