清华大学学报（自然科学版）2026，Vol.66Issue(4)：677-690,14.DOI:10.16511/j.cnki.qhdxxb.2024.27.038
微重力环境下复杂燃料单液滴的蒸发及自着火模拟
Simulation of the evaporation and autoignition of complex fuel single droplets under microgravity conditions
摘要
Abstract
[Objective]Understanding how multicomponent fuel droplets combust in microgravity environments is crucial for characterizing real fuels during spray combustion.Constructing surrogate fuels that represent real fuels is significant,balancing the need for accurate representation of complex,multicomponent fuels with acceptable computational costs.Existing surrogate fuels often match the overall properties of real fuels;however,this can lead to inaccuracies due to differences in how components vaporize due to their volatility.This article aims to study the differences in droplet evaporation and autoignition behaviors among hydrocarbon fuels with various carbon numbers and volatilities in both single-and multi-component scenarios.[Methods]We developed a numerical simulation model for single droplet combustion under the assumption of spherical symmetry for multicomponent fuels.This model solves the one-dimensional convective diffusion equation for heat and mass transfer and the continuity equation for gas and liquid phases.We examined single-component n-alkanes with carbon numbers ranging from 9 to 13 and four multicomponent mixtures with an average carbon number of 10,designed to represent surrogate fuels.For single-component fuels,our analysis focused on the zero-dimensional ignition delay time,ignition delay time for droplet combustion,and droplet radius changes over time.For multicomponent fuels,we also studied component distribution in the gas and liquid phases to understand the coupling relationship between evaporation,diffusion,and reaction during droplet combustion.Our quantitative analysis of ignition delay time involved simulating zero-dimensional ignition time under local temperature and composition throughout the droplet combustion process and the entire space.[Results]The results showed that although zero-dimensional ignition delay times did not differ significantly among components with different carbon numbers,fuel droplets with lower carbon numbers had shorter ignition delay times because of higher volatility.In multicomponent mixtures,despite similar molecular structures,average carbon numbers,and ignition delay times in zero-dimension reactors between the four mixtures and n-decane,there were significant differences in droplet ignition delay times and droplet radius evolution.The analysis revealed that in multicomponent fuels,high-volatility components evaporate first,and low-volatility components evaporate later.With limited liquid mass transfer rates,low-volatility components accumulate on the droplet surface.This accumulation reduces volatility,extends the ignition delay time,and prolongs the droplet combustion lifetime.Our quantitative analysis found that droplet evaporation influences ignition in two ways:it mixes components and propagates the reaction,and it accelerates the ignition process through continuous fuel evaporation.Both processes are closely related to preferential vaporization.[Conclusions]Therefore,surrogate fuel models that match the overall physical and chemical properties of real fuels may exhibit different droplet combustion properties compared with real fuels.This finding highlights the importance of accurately modeling the complex evaporation and combustion processes of multicomponent fuels in microgravity environments to improve spray combustion simulation accuracy.关键词
微重力/复杂燃料/液滴蒸发/液滴燃烧模拟Key words
microgravity/complex fuel/droplet evaporation/droplet combustion simulation分类
信息技术与安全科学引用本文复制引用
孙宇航,宋海玉,刘有晟..微重力环境下复杂燃料单液滴的蒸发及自着火模拟[J].清华大学学报（自然科学版）,2026,66(4):677-690,14.基金项目
国家重点研发计划项目(2021YFA0716201) （2021YFA0716201）
国家自然科学基金面上项目(52076117) （52076117）
