Sensitivity of Ingnition Delay Time and Temperature to Changes in Turbulence Expressed by Magnussen Parameters Academic Article uri icon

abstract

  • A numerical simulation of a time-dependent turbulent spray flame is presented here. The Magnussen Eddy-Dissipation Combustion Model is used for the influence of the turbulence upon the reaction rate. A global 1-step combustion model is employed in order to isolate the effect of one pair of Magnussen parameters on the evolution of the maximum flame temperature. The combustion simulation refers to an experimental study by Koss et al. (1993), in which n-heptane fuel was injected into a high temperature, high pressure environment, and ignited after a delay time of about 1.6 ms. This ignition delay time is also obtained by the present numerical calculations (with the same nominal conditions) which show the appearance of a relatively high temperature region that expands with time. In addition, a 2-step combustion mechanism is employed, for comparison with respect to spot of ignition. According to the 1-step model the ignition occurs in the inner part of the spray stream near the axis of symmetry whereas the spot of ignition obtained by the 2-step is in the shear flow at the edge of the jet.

publication date

  • January 1, 1999