Internal traversing of combustion species inside a methane fuelled

ABSTRACT This paper describes a test programme undertaken by Rolls-Royce plc and QinetiQ Ltd. where a series staged Dry Low Emissions (DLE) combustor was internally traversed in 3 dimensions. The primary motivation of the exercise was to generate gaseous composition data for Combustion CFD validation and to gain greater insight into the changes in the detail of chemical composition along the length of the combustor. The combustor was run at baseload conditions corrected for 10 bar. An RB211 DLE combustion system was modified so that it could be installed into the QinetiQ internal traversing facility. Within this facility a position-calibrated gas-sampling probe was traversed within the combustor. Measurements of gaseous concentrations were made of CO, CO 2 , NO x , NO 2 , HC and O 2 for over 400 points in 6 axial planes in both primary and secondary zones. Data within this paper, however, is reported for the four axial locations of most interest. The combustion temperature, AFR and efficiency were calculated from the gas analysis. A selected summary of the traverse results in terms of the gaseous compositions (NO and NO x ), efficiency and AFR is included. Combustor performance in terms of efficiency, mixing and emissions has also been evaluated. The results show that although the combustion contains a great deal of structure at the inlets to both the primary and secondary zones, efficiency is close to 100% by the exit of each zone. Peak NOx emissions identified in the primary zone reached acceptable values by the combustor exit plane. Although a large number of points were measured, recommendations include further work with different operating conditions and better coverage of each axial plane

Evolution of Carbonaceous Aerosol and Aerosol Precursor Emissions Through a Jet Engine

This study conducted during the summers of 2000 and 2001 represents the first measurement and model intercomparison that tracks detailed gaseous and aerosol emissions through a gas turbine engine. Its primary objective was to determine the impacts of engine operational state on the evolution of carbonaceous aerosol and aerosol precursors. Emissions measurements were performed at the exit of a combustor and at the exit of a full engine for a gas turbine engine typical of the in-service, commercial aircraft fleet. Measurements were compared to model simulations of changes in gaseous chemistry. As predicted by the model simulations, results show no significant modifications to the aerosol distribution along the postcombustor flowpath. The oxidation of NO to HONO was measured. Trends with engine power setting and sulfur loading were at the level of estimated uncertainty limits. Simulations of the fluid and chemical processes through the turbine and exhaust nozzle correctly captured HONO trends and matched experimental data within measurement uncertainty. This suggests that the employed modeling approach is valid for HONO chemistry, and more generally, because HONO results from NO oxidation via the hydroxyl radical, indicates the importance of OH-driven oxidation through the engine. These results indicate that the chemical and physical processes occurring in the turbine are important in determining aircraft engine emission