Barry C. Schlein

Evaluation of low-NOx combustor concepts for aeroderivative gas turbine engines

An experimental program was conducted to evaluate low-NOx combustor concepts applicable to natural-gas-burning aeroderivative gas turbine engines operating at a nominal pressure ratio of 20:1. Gas sampling measurements at the exit of the primary zone of high-shear and lean premixed burners were acquired under elevated entrance pressure and temperature conditions over a range of primary zone equivalence ratios. Piloting systems were incorporated in most of the burner designs to achieve satisfactory burner operability. Both swirl stabilized and perforated-plate (grid) stabilized burners were found to produce NOx levels lower than the current engine goal of 25 ppm (15 percent O2 ).

Evaluation of Low NOx Combustor Concepts for Aeroderivative Gas Turbine Engines

An experimental program was conducted to evaluate low NOx combustor concepts applicable to natural-gas-burning aeroderivative gas turbine engines operating at a nominal pressure ratio of 20:1. Gas sampling measurements at the exit of the primary zone of high-shear and lean premixed burners were acquired under elevated entrance pressure and temperature conditions over a range of primary zone equivalence ratios. Piloting systems were incorporated in most of the burner designs to achieve satisfactory burner operability. Both swirl stabilized and perforated-plate (grid) stabilized burners were found to produce NOx levels lower than the current engine goal of 25 ppm (15% O2).Copyright

Emission and Performance of a Lean-Premixed Gas Fuel Injection System for Aeroderivative Gas Turbine Engines

A dry-low-NOx, high-airflow-capacity fuel injection system for a lean-premixed combustor has been developed for a moderate pressure ratio (20:1) aeroderivative gas turbine engine. Engine requirements for combustor pressure drop, emissions, and operability have been met. Combustion performance was evaluated at high power conditions in a high-pressure, single-nozzle test facility which operates at full baseload conditions. Single digit NOx levels and high combustion efficiency were achieved A wide operability range with no signs of flashback, autoignition, or thermal problems was demonsuated. NOx sensitivities 10 pressure and residence time were found to be small at flame temperatures below 1850 K (2870 F). Above 1850 K some NOx sensitivity to pressure and residence Lime was observed and was associated with the increased role of the thermal NOx production mechanism at elevated flame temperatures.Copyright

Full Annular Rig Development of the FT8 Gas Turbine Combustor

In this paper the results of developmental testing in a high-pressure, full annular combustion section of the FT8 industrial gas turbine are presented. Base power conditions were simulated at approximately 60 percent of burner pressure. All aspects of combustion performance with liquid fuel were investigation, including staring, blowout, exit temperature signature, emissions, smoke, and liner wall temperature. Configurational change were made to improve liner cooling, reduce emissions, adjust pressure loss, and modify exit temperature profile. The effects of water injection on emissions and performance were evaluated in the final test run. Satisfactory performance in all areas was demonstrated with further refinements to be carried out during developmental engine testing.

FT8-3 Advanced Low Emissions Combustor Design

Pratt & Whitney has developed a novel water-injected Industrial Gas Turbine (IGT) combustor liner design that has demonstrated significant reduction in CO emissions when compared to typical film cooled combustor designs. The CO reduction demonstrated in a prototype test shows that the CO quenching due to cooler film temperatures near the liner wall is a significant source of CO emissions in a conventional water-injected combustor operating on natural gas fuel. This finding paved the way for a combustor design that reduces CO emissions while still maintaining low levels of NOx emissions. This design also has potential for lower NOx since the low CO emissions characteristic enables increased water-injection. This paper presents the emissions characteristics measured on prototype hardware and the design of the engine hardware for future validation. Significant reduction in gaseous emissions was demonstrated with the testing of a prototype at the United Technologies Research Center in East Hartford, CT. This reduction in emissions compared to the baseline film-cooled design for a given operating condition has many benefits to the customer, including reduced need for exhaust catalyst cleanup and extended operating times while still meeting site permits specified in CO tons per year. Other benefits may include the ability to guarantee lower NOx emissions through increased water injection for the current CO emissions output.© 2010 ASME

Gas Turbine Combustion Efficiency

A method of correlating combustor efficiency as a function of geometry and operating conditions is presented. A simple equation correlates all the data for a given engine type with a single parameter. The correlating parameter is a function of fuel flow, pressure, temperature and volume in a form similar to others in the literature. The unique feature of the correlating parameter is its use of internal gas temperature rather than the commonly used combustor inlet temperature. The result is an equation requiring an iterative solution since combustion efficiency is a part of the correlating parameter. With use of a computer this is easily handled. The correlation fits engine data over all flight conditions from high altitude, high Mach number to sea level idle. The correlation is compared to engine test data for several engines.Copyright