Experimental Study of Gas Turbine Combustion With Elevated Fuel Temperatures

The effects of elevated fuel temperatures on the performance and emissions of a Rolls–Royce 501K combustor with a modified fuel injector designed to handle two-phase flow is investigated in this study. A series of tests were run using Jet-A fuel at ambient, 250, 450, and 600 °F fuel temperatures. The influence of the new fuel injector design was compared with previously collected test data using a legacy 501 K fuel injector. In addition to conventional pressure and temperature instrumentation, high frequency pressure measurements and emissions of unburned hydrocarbons (UHC), carbon monoxide (CO), and oxides of nitrogen (NO_x) were recorded. In order to mitigate autoxidative coking, nitrogen sparging and catalytic deoxygenation were employed to remove dissolved oxygen from the fuel during high temperature tests. Oxygen levels in the fuel prior to heating were on average less than 0.2% of fully saturated values. Possible variations in fuel makeup and density due to the deoxygenation methods are discussed. At the highest fuel temperatures, test conditions with combustion pressures below the vaporization pressure of the fuel led to lower combustion efficiencies most likely due to flashing in the injector. The trends in combustion efficiency and emissions levels due to increasing fuel temperatures are analyzed in this paper.