Autoignition and Vaporization of No. 3 Diesel Oil Spray Under Lean Conditions

Spray or heterogeneous autoignition has recently taken on great importance with the advent of low emission (NOx) combustors requiring precise control of the primary zone equivalence ratio. Many of these combustors, particularly lean premixed systems rely on the prevaporation and mixing of the fuel and air prior and external to the primary zone combustion process. At high pressures and temperatures, heterogeneous autoignition occurs readily and it can prevent the necessary (for low NOx) premixing and prevaporization of the fuel and air. Experimental results of an investigation into the relationship between vaporization and autoignition has revealed that the necessary level of mixing and vaporization for low NOx can be achieved without autoignition for most of the present industrial gas turbine engines.