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Title: Turbulent flame-wall interaction: a DNS study

Abstract

A turbulent flame-wall interaction (FWI) configuration is studied using three-dimensional direct numerical simulation (DNS) and detailed chemical kinetics. The simulations are used to investigate the effects of the wall turbulent boundary layer (i) on the structure of a hydrogen-air premixed flame, (ii) on its near-wall propagation characteristics and (iii) on the spatial and temporal patterns of the convective wall heat flux. Results show that the local flame thickness and propagation speed vary between the core flow and the boundary layer, resulting in a regime change from flamelet near the channel centreline to a thickened flame at the wall. This finding has strong implications for the modelling of turbulent combustion using Reynolds-averaged Navier-Stokes or large-eddy simulation techniques. Moreover, the DNS results suggest that the near-wall coherent turbulent structures play an important role on the convective wall heat transfer by pushing the hot reactive zone towards the cold solid surface. At the wall, exothermic radical recombination reactions become important, and are responsible for approximately 70% of the overall heat release rate at the wall. Spectral analysis of the convective wall heat flux provides an unambiguous picture of its spatial and temporal patterns, previously unobserved, that is directly related to the spatial andmore » temporal characteristic scalings of the coherent near-wall turbulent structures.« less

Authors:
 [1];  [1];  [2];  [3]
  1. Sandia National Laboratories (SNL)
  2. ORNL
  3. SINTEF Energy Research
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Center for Computational Sciences
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1043299
DOE Contract Number:  
DE-AC05-00OR22725
Resource Type:
Journal Article
Journal Name:
Journal of Fluid Mechanics
Additional Journal Information:
Journal Volume: 658; Journal Issue: 1; Journal ID: ISSN 0022-1120
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; 42 ENGINEERING; AIR; BOUNDARY LAYERS; COMBUSTION; CONFIGURATION; FLAME PROPAGATION; FLAMES; HEAT FLUX; HEAT TRANSFER; HYDROGEN; CHEMICAL REACTION KINETICS; NUMERICAL ANALYSIS; RADICALS; RECOMBINATION; SIMULATION; THICKNESS; TURBULENCE; VELOCITY; WALL EFFECTS

Citation Formats

Chen, Jackie, Hawkes, Evatt R, Sankaran, Ramanan, and Gruber, Andrea. Turbulent flame-wall interaction: a DNS study. United States: N. p., 2010. Web.
Chen, Jackie, Hawkes, Evatt R, Sankaran, Ramanan, & Gruber, Andrea. Turbulent flame-wall interaction: a DNS study. United States.
Chen, Jackie, Hawkes, Evatt R, Sankaran, Ramanan, and Gruber, Andrea. Fri . "Turbulent flame-wall interaction: a DNS study". United States.
@article{osti_1043299,
title = {Turbulent flame-wall interaction: a DNS study},
author = {Chen, Jackie and Hawkes, Evatt R and Sankaran, Ramanan and Gruber, Andrea},
abstractNote = {A turbulent flame-wall interaction (FWI) configuration is studied using three-dimensional direct numerical simulation (DNS) and detailed chemical kinetics. The simulations are used to investigate the effects of the wall turbulent boundary layer (i) on the structure of a hydrogen-air premixed flame, (ii) on its near-wall propagation characteristics and (iii) on the spatial and temporal patterns of the convective wall heat flux. Results show that the local flame thickness and propagation speed vary between the core flow and the boundary layer, resulting in a regime change from flamelet near the channel centreline to a thickened flame at the wall. This finding has strong implications for the modelling of turbulent combustion using Reynolds-averaged Navier-Stokes or large-eddy simulation techniques. Moreover, the DNS results suggest that the near-wall coherent turbulent structures play an important role on the convective wall heat transfer by pushing the hot reactive zone towards the cold solid surface. At the wall, exothermic radical recombination reactions become important, and are responsible for approximately 70% of the overall heat release rate at the wall. Spectral analysis of the convective wall heat flux provides an unambiguous picture of its spatial and temporal patterns, previously unobserved, that is directly related to the spatial and temporal characteristic scalings of the coherent near-wall turbulent structures.},
doi = {},
url = {https://www.osti.gov/biblio/1043299}, journal = {Journal of Fluid Mechanics},
issn = {0022-1120},
number = 1,
volume = 658,
place = {United States},
year = {2010},
month = {1}
}