Modeling of Hydrogen Jet Diffusion Flames (On the Direct Influence of Molecular Viscoty

It was believed that the increase of molecular viscosity due to high temperature raises the dissipation rate of turbulence in low-turbulent regions in a combustion field. Hence, the objective of the present study was to verify this both experimentally and theoretically. Experiments were carried out on jet diffusion flames of hydrogen, and then, a numerical simulation was conducted for the experimental results. In the simulation, the κ-ε two-equation model was used as a turbulence model and a new source term was added to the κ-equation to represent the dissipation rate of turbulence kinetic energy due to molecular viscosity. The calculated results agree well with the experimental ones. It was found that the new source term suppresses turbulence in low turbulent regions situated around the nozzle exit and the periphery of jets, and changes the condition in the whole combustion field greatly. The present work suggested that consideration of the viscous effect is important in the modeling of turbulent combustion fields.・rights：日本機械学会・rights：本文データは学協会の許諾に基づきCiNiiから複製したものである・relation：isVersionOf：http://ci.nii.ac.jp/naid/110002494156