Large eddy simulation of mixing process for different density gas jets
1. School of Energy and Power Engineering, Jiangsu University, Zhenjiang, Jiangsu 212013, China; 2. Institute for Energy Research, Jiangsu University, Zhenjiang, Jiangsu 212013, China
Abstract：The large eddy simulation of the turbulent mixing process for different density gases in the case of circular tube jet was carried out to investigate the effect of gas density ratio on the downstream gas mixing process. The results show that with helium and carbon dioxide injecting into air, the Reynolds numbers are 7 000 and 32 000, respectively. The calculated results of velocity and mass fraction are in good agreement with the experimental results. For the same jet flow flux, the low-density jets are developed faster than high-density jets. The pseudo-similarity of the variable-density jet is verified, and the coherent vortex structure is analyzed. The turbulent flow fields of carbon dioxide jets at different jet velocities are calculated to show that the low velocity jet has higher mixing rate than the high velocity jet.
张春1, 王平2, 曾海翔1, 李伟超1. 不同密度气体射流混合过程的大涡模拟[J]. 江苏大学学报（自然科学版）, 2019, 40(6): 662-667.
ZHANG Chun1, WANG Ping2, ZENG Haixiang1, LI Weichao1. Large eddy simulation of mixing process for different density gas jets[J]. Journal of Jiangsu University(Natural Science Eidtion)
, 2019, 40(6): 662-667.
DING Y,HAN P P. Numerical study of linearly stratified flow past a cylinder based on a multiphase mixture model［J］. Journal of Harbin Engineering University，2016,37(9):1179-1183.(in Chinese)
WANG R X,JIANG N. Scale similarity of coherent structures and scale-similar sub-grid model［J］. Journal of Harbin Engineering University，2012,33(10):1283-1288. (in Chinese)
［5］
HAKEM M, HAZZAB A, GHENAIM A. Experimental investigation of elliptical jet in coflow［J］. International Journal of Applied Engineering Research,2007, 2(1):31-43.
［6］
JESTER-ZURKER R, JAKIRLIC＇ S,TROPEA C. Computational modelling of turbulent mixing in confined swirling environment under constant and variable density conditions［J］.Flow Turbulence and Combustion, 2005,75(1／2／3／4):217-244.
［7］
WANG P, FROHLICJH J. Large-eddy simulation of varible-density turbulent axisymmetric jets［J］. International Journal of Heat and Fluid Flow,2008, 29(3): 654-664.
［8］
DJERIDANE T, AMIELH M, ANSELMET F, et al. Velocity turbulence properties in the near-field region of axisymmetric variable density jets［J］.Physics of Fluids,1996, 8(6): 1614-1630.
［9］
孙兴. 基于OpenFOAM的平壁射流气膜冷却的大涡模拟研究［D］.大连:大连理工大学,2014.
［10］
FULACHIER L, BORCHI R, ANSELMET F, et al. Influence of density variations on the structures of low-speed turbulent flows:a report on Euromech［J］. Journal of Fluid Mechanics,1989, 203(3):577-593.
［11］
GUBSER S S, NAYAR R, PARIKH S. Strings, vortex rings, and modes of instability［J］. Nuclear Physics B, 2015, 892:156-180.
［12］
ASWIN G, JOSETTE B. Side-jet effects in high-pressure turbulent flows: direct numerical simulation of nitrogen injected into carbon dioxide［J］.The Journal of Supercritical Fluid, doi:10.1016／j.supflu.2018.04.015.
［13］
GARCIA-VILLALBA M, FROHLICH J, RODI W. Identification and analysis of coherent structures in the near field of a turbulent unconfined annular swirling jet using large eddy simulation［J］. Physics of Fluids, 2006, 18(5):055103.
［14］
EVGENIY S, DIMITRIS D. Artificial compressibility, characteristics-based schemes for variable-density, in-compressible, multispecies flows: part II multigrid implementation and numerical tests［J］.Journal of Computational Physics, 2005, 210(2): 608-631.
［15］
REINAUD J, JOLY L, CHASSAING P. Numerical si-mulation of a variable-density mixing-layer［J］. Workshop on Vortex Flows and Related Numerical Methods, 1999, 7:359-368.
WANG B Y,ZHANG J Z,LYU Y W.Numerical study on convective heat transfer characteristics of lobed nozzle jet impingement onto a flat target［J］.Journal of Chongqing University of Technology(Natural Science),2018,32(4):86-93. (in Chinese)
2019, Vol. 40 
