Unexpected Propagation of Ultra-Lean Hydrogen Flames in Narrow Gaps Articles uri icon

publication date

  • May 2020

issue

  • 17

volume

  • 124

International Standard Serial Number (ISSN)

  • 0031-9007

Electronic International Standard Serial Number (EISSN)

  • 1079-7114

abstract

  • Very lean hydrogen flames were thought to quench in narrow confined geometries. We show for the first time how flames with very low fuel concentration undergo an unprecedented propagation in narrow gaps: H2-air flames can survive very adverse conditions by breaking the reaction front into isolated flame cells that travel steadily in straight lines or split to perform a fractal-like propagation that resembles the pathway of starving fungi or bacteria. The combined effect of hydrogen mass diffusivity and intense heat losses act as the two main mechanisms that explain the experimental observations.