Gas-phase transient effects on droplet evaporation and ignition

Shangpeng Li, Huangwei Zhang, Chung K. Law

Research output: Contribution to journalArticlepeer-review

2 Scopus citations

Abstract

In order to achieve high efficiency and power density, modern combustors are generally operated at elevated pressures. As the pressure and gas-phase density increase, classical quasi-steady (QS) models of droplet evaporation, ignition, and burning introduce non-negligible errors. In this paper, we extend the QS model to incorporate the gas-phase transient (GT) effect by examining the development of the evaporating boundary layer near the droplet surface. Specifically, the evaporation and ignition of single droplets in an infinite, hot, and oxidizing environment are analyzed. The theoretical result agrees well with the transient numerical simulation for an extensive range of parameters. The proposed theory successfully predicts the GT effect on evaporation lifetime and critical ignition limit of droplets. It is demonstrated that the GT effect increases the droplet evaporation rate while tends to suppress ignition. In comparison with pure evaporation, the ignition of droplets is more severely affected. Additionally, the GT effect increases as the liquid-to-gas density ratio decreases or evaporation intensity increases.

Original languageEnglish (US)
Article number112840
JournalCombustion and Flame
Volume254
DOIs
StatePublished - Aug 2023

All Science Journal Classification (ASJC) codes

  • General Chemistry
  • General Chemical Engineering
  • Fuel Technology
  • Energy Engineering and Power Technology
  • General Physics and Astronomy

Keywords

  • Droplet evaporation
  • Droplet ignition
  • Evaporating boundary layer
  • Gas-phase transient effect
  • Quasi-steady assumption

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