Evaporation Characteristics of Ethanol Diesel Droplets Containing Nanoparticles

doi:10.1007/s12204-021-2280-x

Abstract

Abstract: Evaporation plays an important role in the cylinder combustion process, so the study of fuel evaporation characteristics is very important to improve the combustion performance of internal combustion engine. In this study, ethanol diesel was used as the base fuel. The evaporation characteristics of droplets at different ambient temperatures (623K, 923K) were investigated by adding alumina nanoparticles with different mass fractions (1%, 2.5%) to ethanol diesel. The results show that the evaporation states of three kinds of droplets (ethanol diesel, base fuel with 1% alumina nanoparticles, base fuel with 2.5% alumina nanoparticles) are similar in the low temperature environment, and nanoparticles inhibit the evaporation of the droplets. At low temperature, the higher the concentration of nanoparticles is, the slower the evaporation rate is. However, in the high temperature environment, nanoparticles significantly promote droplet evaporation, and the phenomenon of micro explosion is obvious. By analyzing the evaporation processes of two different temperatures, we know that nanoparticles first gather on the surface of the droplet, then form a protective shell, and finally reduce the evaporation rate of the droplet at low temperature. In the high temperature environment, nucleation sites and bubbles are formed in the interior of the droplet; as the droplet is heated further, nucleation sites and bubbles first gather and then fuse; the bubbles gradually expand and burst rapidly, causing micro explosion of the droplets, and most of them are evaporated in the micro explosion.

Key words: ethanol diesel| nanoparticles| droplet evaporation| bubble| micro explosion

摘要： Evaporation plays an important role in the cylinder combustion process, so the study of fuel evaporation characteristics is very important to improve the combustion performance of internal combustion engine. In this study, ethanol diesel was used as the base fuel. The evaporation characteristics of droplets at different ambient temperatures (623K, 923K) were investigated by adding alumina nanoparticles with different mass fractions (1%, 2.5%) to ethanol diesel. The results show that the evaporation states of three kinds of droplets (ethanol diesel, base fuel with 1% alumina nanoparticles, base fuel with 2.5% alumina nanoparticles) are similar in the low temperature environment, and nanoparticles inhibit the evaporation of the droplets. At low temperature, the higher the concentration of nanoparticles is, the slower the evaporation rate is. However, in the high temperature environment, nanoparticles significantly promote droplet evaporation, and the phenomenon of micro explosion is obvious. By analyzing the evaporation processes of two different temperatures, we know that nanoparticles first gather on the surface of the droplet, then form a protective shell, and finally reduce the evaporation rate of the droplet at low temperature. In the high temperature environment, nucleation sites and bubbles are formed in the interior of the droplet; as the droplet is heated further, nucleation sites and bubbles first gather and then fuse; the bubbles gradually expand and burst rapidly, causing micro explosion of the droplets, and most of them are evaporated in the micro explosion.

关键词: ethanol diesel| nanoparticles| droplet evaporation| bubble| micro explosion

CLC Number:

TK 6

WANG Xiaorong (王筱蓉), WEI Ning (韦宁), GAO Ji (高吉), YAN Jun (严俊), JIANG Genzhu (姜根柱). Evaporation Characteristics of Ethanol Diesel Droplets Containing Nanoparticles[J]. J Shanghai Jiaotong Univ Sci, 2021, 26(2): 201-209.

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