An atmospheric test program was conducted to define a low NOx annular combustor concept suitable for a supersonic, high-altitude aircraft application. The lean premixed combustor, known as the Vortex Air Blast (VAB) concept, was tested as a 22.0 cm diameter model in the early development phases to arrive at basic design and performance criteria. Final demonstration testing was carried out on a full scale combustor of 0.66 m diameter. Variable geometry dilution ports were incorporated to allow operation of the combustor across the range of conditions between idle (Tin = 422 K, Tout = 917 K) and cruise (Tin = 833 K, Tout = 1778 K). Test results showed that the design could meet the program NOx goal of 1.0 g NO2/kg fuel at a reduced atmospheric cruise condition.

An experimental rig program has been conducted with the objective of evaluating the combustion performance of a family of fuel gases based on a mixture of hydrogen and carbon monoxide. These gases, in addition to being members of a family, were also representative of those secondary fuels that could be produced from coal by various gasification schemes. In particular, simulated Winkler, Lurgi, and Blue-water low and medium energy content gases were used as fuels in the experimental combustor rig. The combustor used was originally designed as a low NOx rich-lean system for burning liquid fuels with high bound nitrogen levels. When used with the above gaseous fuels this combustor was operated in a lean-lean mode with ultra long residence times. The Blue-';water gas was also operated in a rich-lean mode. The results of these tests indicate the possibility of the existence of an "optimum" Las turbine hydrogen -carbon monoxide based secondary fuel. Such a fuel would exhibit low NOx and high efficiency over the entire engine operating range. It would also have sufficient stability range to allow normal light-off and engine acceleration. Solar Turbines Incorporated would like to emphasize that the results presented here have been obtained with experimental rig combustors. The technologies generated could, however, be utilized in future commercial gas turbines.

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The United States federal new source performance standards (NSPS) for stationary gas turbines contain NO, limits that are standardized based on the International Standards Organization (ISO) standard for ambient conditions. The measured NO, emissions from stationary gas turbines at test conditions are to be corrected to ISO standard ambient conditions using a recommended equation, which was developed using data from conventional (diffusion flame) combustion systems. It is geneanly expected that this correction equation will require a revision when advanced lean premixed or hybrid combustion system is utilized.At the site of the first Mars 1005 SoLoNO, gas turbine, a continuous emissions and gas turbine performance data gathering system has been installed. From the data gathered, the nonapplicability of this NO, ambient correction equation is demonstrated. This points to the need to develop a custom NO, ambient correction equation for gas turbines with an advanced lean premixed system.Using a proven NO, model, the humidity effect on NO, emissions from an advanced lean premixed system is determined to be much stronger than that for a conventional combustion system. The humidity effect was determined based on an engineering application of the NO, model. Through statistical analyses, this stronger humidity effect is supported by more than one thousand five hundred data points gathered over a eight-month period at the above customer's site, covering an ambient temperature range over 100°F (56°C). Using this newly determined humidity effect and a least-square curve fit of the data, a custom NO, ambient correction equation has been developed for this prototype Man SoLoNO, gas turbine.

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