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FLAME AND EDDY STRUCTURES IN HYDROGEN−AIR TURBULENT JET PREMIXED FLAME

Masayasu Shimura
Department of Mechanical and Aerospace Engineering Tokyo Institute of Technology 2-12-1 Ookayama, Meguro-ku, Tokyo, 152-8550, Japan

K. Yamawaki
Department of Mechanical and Aerospace Engineering Tokyo Institute of Technology 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550, Japan

Y.-S. Shim
Department of Mechanical and Aerospace Engineering Tokyo Institute of Technology 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550, Japan

Mamoru Tanahashi
Department of Mechanical and Aerospace Engineering Tokyo Institute of Technology 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550, Japan

Toshio Miyauchi
Dept. Mechanical and Aerospace Eng., Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8552, Japan; Organization for the Strategic Coordination of Research and Intellectual Properties Meiji University 1-1-1 Higashimita, Tama-ku, Kawasaki, Kanagawa, Japan

Аннотация

Three-dimensional direct numerical simulation (DNS) of hydrogen−air turbulent plane jet premixed flames, which are composed of high-speed unburnt mixture gas and surrounding burnt gas for flame holding, have been conducted. Fully-developed homogeneous isotropic turbulence is superimposed on the high speed mean flow under the assumption that a turbulence gird is installed in the upstream. A detailed kinetic mechanism including 12 species and 27 elementary reactions is considered. Eddy structures which have large-scale in space and streamwise rotating axis are produced along the outer edge of OH layer in burnt gas. These streamwise eddies are induced by velocity difference due to strong expansion of the burnt gas. Although combustion condition of the present DNS is classified into corrugated flamelets regime, unburnt mixture islands frequently appear behind the main flame. The creation of these islands is closely related to the fine-scale eddies in the unburnt turbulence and the separated unburnt mixture is consumed rapidly by the heating from surrounding burnt gas.