Effects of Lewis and Karlovitz numbers on transport equations for turbulent kinetic energy and enstrophy Lewis数和Karlovitz数对湍流动能和拟能输运方程的影响

Lee，Hsu Chew1; Liu，Xiaoyu1; Dai，Peng1; Chen，Zheng2; Abdelsamie，Abouelmagd3; Wan，Minping1,4

2022-07-01

10.1007/s10409-022-09030-8

ACTA MECHANICA SINICA   Impact Factor & Quartile

0567-7718

1614-3116

A three-dimensional Direct numerical simulation (DNS) with complex chemistry was employed to examine the statistical behavior of turbulent kinetic energy (TKE) and enstrophy transport equations in hydrogen (Lewis number (Le) ≈ 0.4) and dodecane (Le ≈ 4.2) flames. The Karlovitz (Ka) numbers ranged from 4 to 150, involving both the thin and broken reaction zones. Budget analyses of TKE and enstrophy transport equations are performed, and scaling terms in the literature are re-examined. Similar to thin reaction zone flames, viscous dissipation term appears to be the most important term in the TKE balance, while viscous dissipation and vortex-stretching terms are the dominant terms in the enstrophy transport equation at high Ka number. The velocity-pressure gradient and the mean velocity dilatation in the TKE transport equation and the dilatation term in enstrophy budget are found to be affected by the Le. Modified scaling estimations for those terms affected by Le are proposed in this work to account for the Le effects spanning different combustion regimes. This work confirmed that Kolmogorov’s first hypothesis is not valid for low Ka number flames investigated in this study, where the vortex stretching and viscous dissipation terms cannot be scaled with local dissipation and viscosity. At sufficiently high Ka number flames, the vorticity can be scaled with the Kolmogorov time scale, and the mean enstrophy value approaches homogeneous, isotropic, non-reacting turbulence flow, but lower Le fuels require much higher Ka number to achieve that.

Complex chemistry Direct numerical simulations Lewis number Turbulent premixed flames

SCI ; EI

Chinese

First ; Corresponding

National Natural Science Foundation of China[91752201,11672123] ; Shenzhen Science and Technology Program["JCYJ20170412151759222","JCYJ201803 02173952945","KQTD20180411143441009"] ; Department of Science and Technology of Guangdong Province[2019B21203001] ; Joint Program of Shenzhen Clean Energy Research Institute and SUSTech["LCH-2019011","CERI-KY-2019-003"]

Engineering ; Mechanics

Engineering, Mechanical ; Mechanics

WOS:000813789200008

SPRINGER HEIDELBERG

20222512254166

Budget control ; Combustion ; Computational complexity ; Kinetic energy ; Kinetics ; Numerical models ; Viscous flow ; Vortex flow

Fluid Flow, General:631.1 ; Computer Theory, Includes Formal Logic, Automata Theory, Switching Theory, Programming Theory:721.1 ; Computer Applications:723.5 ; Mathematics:921 ; Classical Physics; Quantum Theory; Relativity:931

ENGINEERING

2-s2.0-85132143607

Scopus

1.Guangdong Provincial Key Laboratory of Turbulence Research and Applications,Department of Mechanics and Aerospace Engineering,Southern University of Science and Technology,Shenzhen,518055,China
2.Department of Mechanics and Engineering Science,College of Engineering,Peking University,Beijing,100871,China
3.Laboratory of Fluid Dynamics and Technical Flows,University of Magdeburg “Otto von Guericke”,Magdeburg,39106,Germany
4.National Center for Applied Mathematics Shenzhen,Shenzhen,518055,China

Lee，Hsu Chew,Liu，Xiaoyu,Dai，Peng,等. Effects of Lewis and Karlovitz numbers on transport equations for turbulent kinetic energy and enstrophy Lewis数和Karlovitz数对湍流动能和拟能输运方程的影响[J]. ACTA MECHANICA SINICA,2022,38(7).

Lee，Hsu Chew,Liu，Xiaoyu,Dai，Peng,Chen，Zheng,Abdelsamie，Abouelmagd,&Wan，Minping.(2022).Effects of Lewis and Karlovitz numbers on transport equations for turbulent kinetic energy and enstrophy Lewis数和Karlovitz数对湍流动能和拟能输运方程的影响.ACTA MECHANICA SINICA,38(7).

Lee，Hsu Chew,et al."Effects of Lewis and Karlovitz numbers on transport equations for turbulent kinetic energy and enstrophy Lewis数和Karlovitz数对湍流动能和拟能输运方程的影响".ACTA MECHANICA SINICA 38.7(2022).