Ultra low NOx ultra lean gas turbine primary zones with liquid fuels

Three low NOx gas turbine combustor design concepts, Jet Mix, Grid Mix and radial swirlers, which have been demonstrated to give very low NOx emissions using gaseous fuels have been successfully tested on liquid fuels and low NOx emissions demonstrated. The Jet Mix was shown to have low NOx emissions at atmospheric pressure and has been tested at pressure, with similar low NOx results. Kerosene performance and emissions was very similar to that for propane as the fuel. The scale up of the Jet Mix was found to be possible without increasing the NOx emissions greatly and is a preferable design option to the use of large numbers of smaller Jet Mix modules. Sector tests at pressure showed the Jet Mix design produced emission reductions close to the best of the NASA clean combustor results. The Grid Mix low NOx design was shown to be capable of low NOx performance using kerosene. There was a much wider flame stability than for the Jet Mix design and lower NOx emissions were demonstrated. The radial swirler with vane passage of 76mm wall fuel injection was shown to have ultra low NOx emissions with liquid fuels, only slightly higher than for gaseous fuels. For a high air flow radial swirler it was found that central kerosene injection gave lower NOx emissions than for gaseous fuels and had the potential to yield a NOx EI of below 10 at simulated take off conditions.