Influence of molecular transport on burning rate and conditioned species concentrations in highly turbulent premixed flames
Artikel i vetenskaplig tidskrift, 2021

Apparent inconsistency between (i) experimental and Direct Numerical Simulation (DNS) data that show the significant influence of differential diffusion on turbulent burning rate and (ii) recent complex-chemistry DNS data that indicate mitigation of the influence of differential diffusion on conditioned profiles of various local flame characteristics at high Karlovitz numbers is explored by analyzing new DNS data obtained from lean hydrogen-air turbulent flames. Both aforementioned effects are observed by analyzing the same DNS data provided that the conditioned profiles are sampled from the entire computational domain. On the contrary, the conditioned profiles sampled at the leading edge of the mean flame brush do not indicate the mitigation, but are significantly affected by differential diffusion phenomena,e.g., because reaction zones are highly curved at the leading edge. This observation is consistent with a significant increase in the computed turbulent burning velocity with decreasing Lewis number, with all the results considered jointly being consonant with the leading point concept of premixed turbulent combustion. The concept is further supported by comparing DNS data obtained by allowing for preferential diffusion solely for a single species, either atomic or molecular hydrogen.

Lewis number

DNS

differential diffusion

flame speed

burning velocity

Författare

HsuChew Lee

Southern University of Science and Technology

Peng Dai

Southern University of Science and Technology

Minping Wan

Southern University of Science and Technology

Andrei Lipatnikov

Chalmers, Mekanik och maritima vetenskaper, Förbränning och framdrivningssystem, Förbränning och sprejer

Journal of Fluid Mechanics

0022-1120 (ISSN) 1469-7645 (eISSN)

Vol. 928 A5

Drivkrafter

Hållbar utveckling

Fundament

Grundläggande vetenskaper

Ämneskategorier

Strömningsmekanik och akustik

DOI

10.1017/jfm.2021.794

Mer information

Senast uppdaterat

2021-11-09