Direct numerical simulations of turbulent non-premixed flames: Assessment of turbulence within swirling flows

被引:10
|
作者
Xiao, Hualin [1 ]
Luo, Kun [1 ]
Jin, Tai [2 ]
Wang, Haiou [1 ]
Xing, Jiangkuan [1 ]
Fan, Jianren [1 ]
机构
[1] Zhejiang Univ, State Key Lab Clean Energy Utilizat, Hangzhou 310027, Peoples R China
[2] Zhejiang Univ, Sch Aeronaut & Astronaut, Hangzhou 310027, Peoples R China
基金
中国国家自然科学基金;
关键词
EMISSION CHARACTERISTICS; KINETIC-ENERGY; HEAT RELEASE; STATISTICS; TRANSPORT; DYNAMICS; VELOCITY; FLUCTUATIONS; COMBUSTOR;
D O I
10.1063/5.0035538
中图分类号
O3 [力学];
学科分类号
08 ; 0801 ;
摘要
Direct numerical simulations of non-premixed swirling fuel-rich/fuel-lean flames within a high-pressure model gas turbine combustor are conducted to investigate the flow and flame structures, as well as the transport mechanisms of both turbulent kinetic energy (TKE) and enstrophy. The effects of non-premixed flames upon these characteristics are also analyzed through comparison with the corresponding non-reacting swirling flows. We demonstrate that the turbulence state in the swirling flows behaves axisymmetrically overall in the current cylindrical laboratory-type combustor and is more likely to be cigar shaped in the presence of combustion. The analysis of TKE budgets within non-reacting swirling flows indicates that TKE is predominantly produced by mean shear in the shear layers and redistributed by transport effects from the inner shear layer (ISL) to the internal-recirculation zone; however, these transport effects are suppressed by combustion in fuel-lean non-premixed flames. Although the total pressure effects consume TKE with a similar magnitude in all cases, the essential cause is different. The influence of combustion upon TKE budgets is more significant for fuel-lean flames than for fuel-rich flames as a result of the stronger burning intensity in the ISL of the former. Analysis of enstrophy dynamics shows that dilatation and baroclinic torque play relatively noticeable roles in swirling non-premixed flames, unlike their negligible effects in high-intensity homogeneous isotropic turbulence. The augmentation of baroclinic torque caused by non-premixed swirling combustion mainly arises from the remarkable decrease in density and enhancement of preferential alignment between the vorticity and baroclinic torque vectors.
引用
收藏
页数:18
相关论文
共 50 条
  • [41] A comparative numerical study of premixed and non-premixed ethylene flames
    Egolfopoulos, F.N.
    Dimotakis, P.E.
    Combustion Science and Technology, 2001, 162 (1-6) : 19 - 35
  • [42] A comparative numerical study of premixed and non-premixed ethylene flames
    Egolfopoulos, FN
    Dimotakis, PE
    COMBUSTION SCIENCE AND TECHNOLOGY, 2001, 162 : 19 - 35
  • [43] Stabilization of non-premixed flames in supersonic reactive flows
    Izard, Jean-Francois
    Mura, Arnaud
    COMPTES RENDUS MECANIQUE, 2009, 337 (6-7): : 362 - 372
  • [44] Direct numerical simulation of premixed turbulent flames
    Cant, S
    PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES, 1999, 357 (1764): : 3583 - 3604
  • [45] Low-dimensional manifolds in direct numerical simulations of premixed turbulent flames
    Van Oijen, J. A.
    Bastlaans, R. J. M.
    De Goey, L. P. H.
    PROCEEDINGS OF THE COMBUSTION INSTITUTE, 2007, 31 : 1377 - 1384
  • [46] Identification and analysis of instability in non-premixed swirling flames using LES
    Dinesh, K. K. J. Ranga
    Jenkins, K. W.
    Kirkpatrick, M. P.
    Malalasekera, W.
    COMBUSTION THEORY AND MODELLING, 2009, 13 (06) : 947 - 971
  • [47] The structure of turbulent stratified and premixed methane/air flames I: Non-swirling flows
    Sweeney, Mark S.
    Hochgreb, Simone
    Dunn, Matthew J.
    Barlow, Robert S.
    COMBUSTION AND FLAME, 2012, 159 (09) : 2896 - 2911
  • [48] Numerical investigation of the response of turbulent swirl non-premixed flames to air flow oscillations
    Giusti, Andrea
    Zhang, Huangwei
    Kypraiou, Anna-Maria
    Allison, Patton M.
    Mastorakos, Epaminondas
    INTERNATIONAL JOURNAL OF SPRAY AND COMBUSTION DYNAMICS, 2022, 14 (3-4) : 229 - 237
  • [49] Direct Numerical Simulations of Dual-Fuel Non-Premixed Autoignition
    Demosthenous, Elena
    Mastorakos, Epaminondas
    Cant, Robert Stewart
    COMBUSTION SCIENCE AND TECHNOLOGY, 2016, 188 (4-5) : 542 - 555
  • [50] Using numerics to help the understanding of non-premixed turbulent flames
    Vervisch, L
    PROCEEDINGS OF THE COMBUSTION INSTITUTE, 2000, 28 : 11 - 24