Title: Experimental study of sprays with isooctane, hexane, ethanol and their binary mixtures under different flash boiling intensities

Abstract

Here, this work investigated the behaviors of single-component and multi-component sprays under different flash boiling intensities. Isooctane, hexane, ethanol, isooctane-hexane, and isooctane-ethanol mixtures were used as test fuels. The pressure ratio of the ambient pressure over saturation pressure (R_p) was used as the indicator of the superheated degree. Macroscopic characteristics of the sprays under 10 different R_p (1.1 to 0.14) were investigated using Diffused Backlight Imaging (DBI). Droplet size, which revealed the spray microscopic characteristics, was also investigated using Phase Doppler Anemometry (PDA). The results showed that ambient pressure reduction led to higher flash boiling intensity, significant spray morphology changes, and smaller droplet size, regardless of the fuel type and blend ratios. Spray collapse was observed for all sprays once R_p dropped below 0.3. Spray collapse dramatically increased the liquid penetration length, expanded the near-field spray angle, and reduced the far-field angle for sprays with all the fuels. Fuel properties, such as the latent heat of vaporization, had significant impacts on droplet size distributions, thus altering the liquid penetration length and spray angles. Under similar R_p, sprays with high ethanol content generally had larger droplet sizes compared with other fuel sprays due to the high latent heat of vaporization. Themore » larger droplets caused the high ethanol content sprays to be more resistant to the plume trajectory change, resulting in a smaller far-field spray angle variations with changing R_p. At R_p of 0.28, sprays with the similar latent heat of vaporization have similar droplet sizes, and droplet sizes at different radial locations were also similar to each other.« less

Authors:

Yan, Junhao ^[1]; Gao, Suya ^[1]; Zhao, Weihua ^[2]; Lee, Timothy H. ^[3]; Lee, Chia-Fon ^[1]

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+ Show Author Affiliations

1. Univ. of Illinois at Urbana-Champaign, IL (United States)
2. Univ. of Illinois at Urbana-Champaign, IL (United States); Beijing Institute of Technology (China)
3. Zhejiang Univ. (China)

Publication Date:

Fri Jul 23 00:00:00 EDT 2021

Research Org.:

Univ. of Illinois at Urbana-Champaign, IL (United States)

Sponsoring Org.:

USDOE Office of Energy Efficiency and Renewable Energy (EERE); USDOD

OSTI Identifier:

1977187

Alternate Identifier(s):

OSTI ID: 1809916

Grant/Contract Number:  

EE0007309

Resource Type:

Accepted Manuscript

Journal Name:

International Journal of Heat and Mass Transfer

Additional Journal Information:

Journal Volume: 179; Journal Issue: C; Journal ID: ISSN 0017-9310

Publisher:

Elsevier

Country of Publication:

United States

Language:

English

Subject:

42 ENGINEERING; Flash boiling spray; Multi-component fuel; Ethanol; Droplet size; Spray collapse; Gasoline engines