Numerical Investigation of the Parameter Governing the Ignitability of a Spray Flame

This paper contains a numerical examination concerning the ignition behavior of a spray nozzle mounted in a rectangular channel under atmospheric conditions which is run with Jet A-1. On the basis of a comprehensive data set of experimental results, the numerical approach is verified primarily by means of a comparison of the flame growth and position after ignition. In the following several distinct igniter positions and boundary condition settings are simulated. The conditions which prevail at the location of the ignition are investigated with respect to how they influence the ignition process. Due to changes in the fuel placement and flow field characteristics which follow from alternating the boundary conditions such as air and fuel mass flow, ignition is either promoted or impeded. The underlying causes which can lead to a success or failure of the ignition are analyzed. The ignition in the experiment is achieved through a laser-induced breakdown, which is modelled through a Turbulent Flame Speed Closure combustion model with an additional spark ignition extension. A comparison with the ignition statistics from the experiment shows that numerical tools can be used to determine preferential boundary conditions and igniter locations to accomplish a successful ignition in multiphase flow configurations.Copyright © 2012 by ASME