Large-eddy simulation of a three-feed non-premixed flame for an oxy-fuel gas turbine burner

The development of turbulent combustion models for a three-feed non-premixed flame is essential for the research of gas-turbine in the oxy-fuel integrated coal gasification combined cycle (IGCC) system. The quasi-two-dimensional flamelet models are considered effective and accurate substitutes for the two-dimensional flamelet model, however, there are still many aspects worth further investigations in terms of each dimension in the flamelet library. The considerations of heat loss, the presumed probability density function (PDF), and the resolution of the diluent fraction in large-eddy simulation (LES) should be attached importance to. In this paper, heat loss, diluent fraction PDF, and resolution of the diluent fraction have been investigated. It has been shown that the current heat loss model in the flamelet equation can correctly interpret the reactions which are facilitated by high temperature. The beta-PDF used for diluent fraction results in a lower temperature in the flame zone than that of the delta-PDF as the diluent fraction fluctuation cannot be overlooked. And also, coarse resolution in terms of the diluent fraction gives interpolation error and shoud be paid attention to.