Implicit large eddy simulation of vitiation effects in supersonic air/H-2 combustion


KARACA M. , Zhao S., Fedioun I., Lardjane N.

AEROSPACE SCIENCE AND TECHNOLOGY, vol.89, pp.89-99, 2019 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 89
  • Publication Date: 2019
  • Doi Number: 10.1016/j.ast.2019.03.050
  • Title of Journal : AEROSPACE SCIENCE AND TECHNOLOGY
  • Page Numbers: pp.89-99
  • Keywords: Vitiation, Implicit LES, Turbulent combustion, Non-premixed flames, DEPENDENT BOUNDARY-CONDITIONS, CONDITIONAL MOMENT CLOSURE, NUMERICAL-SIMULATION, TURBULENT, OXIDATION, IGNITION, SCHEMES, MODEL, AIR

Abstract

This paper presents and discusses Implicit Large Eddy Simulation (ILES) results of vitiation effects in ground tests of supersonic air/H-2 combustion. This work is useful for realistic extrapolation of ground test data to flight conditions. The high-enthalpy flow configuration retained, typical of scramjet engines, is the Mach 2 LAERTE combustion chamber of the French aerospace lab ONERA. The supersonic air co-flow is preheated by burning a small amount of hydrogen in oxygen-enriched air. Stable numerical simulations of such high-speed turbulent shocked flows require dissipative numerics that interact with molecular diffusion. The premature ignition in the case of vitiation by oxygen atom can be observed using reduced finite rate chemistry in the quasi-laminar approximation, i.e. without any subgrid combustion model, because the Damkohler number (ratio of turbulent to chemical time scale) is less than unity. Turbulent time scales are only moderately affected by vitiation, but chemical time scales are significantly reduced. (C) 2019 Elsevier Masson SAS. All rights reserved.