Experimental and numerical study on flow/flame interactions and pollutant emissions of premixed methane-air flames with enhanced lean blowout hydrogen injection

Medhat A. Nemitallah*, Ahmed Abdelhalim, Ahmed Abdelhafez, Mohamed A. Habib

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

This study investigates experimentally and numerically the stability, combustion, and emissions characteristics of premixed swirl-stabilized methane/air flames with enhanced lean blowout (ELBO) injection of hydrogen in the non-premixed mode for higher turndown ratio gas turbines. The study analyzed the effects of hydrogen fraction (HF: volumetric percentage of H2 in the total fuel) ranging from 0 to 25% and equivalence ratio (φ) ranging from 0.5 to 0.893 on flow/flame interactions and flame stability, structure, and emissions. The introduction of non-premixed H2 yields two conflicting outcomes, with enhancements in reaction kinetics and flame speed yet counteracted by increased hydrogen jet momentum dispersing the flame. The combustor lean blowout (LBO) limit remains relatively unaffected (φ overall ≈ 0.5) by H2 injection. Flame temperature is primarily influenced by φ and minorly by HF. Increasing HF resulted in localized temperature rises around H2 jets without an overall increase in flame temperature, offering a promising strategy for reduction of NOx emissions. Nevertheless, using H2 as a pilot fuel leads to an increase in intermediate species like OH, H, and O, contributing to flame stabilization. However, this practice also results in higher CO and unburned hydrocarbons emissions due to the inherent characteristics and heightened reactivity of H2.

Original languageEnglish
Pages (from-to)14-32
Number of pages19
JournalInternational Journal of Hydrogen Energy
Volume65
DOIs
StatePublished - 2 May 2024

Bibliographical note

Publisher Copyright:
© 2024 Hydrogen Energy Publications LLC

Keywords

  • Dry low NOx (DLN) burner
  • Enhanced lean blowout (ELBO) combustion
  • Flame stability
  • Gas-turbine combustor
  • Hydrogen injection
  • Stratified combustion

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment
  • Fuel Technology
  • Condensed Matter Physics
  • Energy Engineering and Power Technology

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