Combustion System Update SGT5-4000F: Design, Testing and Validation

The first Siemens AG SGT5-4000F engine with hybrid burner ring combustor (HBR) was introduced in 1996. Since then, frequent evolutionary design improvements of the combustion system were introduced to fulfill the continuously changing market requirements. The improvements particularly focused on increased thermodynamic performance, reduced emissions, and increasing operational flexibility in terms of load gradients, fuel flexibility, and turndown capability.According to the Siemens product development process, every design evolution had to pass several validation steps to ensure high reliability and best performance. The single steps included cold flow and mixing tests at atmospheric pressure, high-pressure combustion tests in full-scale sector combustion test rigs, and full engine tests at the Berlin test facility (BTF).After successful validation, the design improvements were gradually released for commercial operation. In a first step, cooling air reduction features have been implemented in 2005, followed by the introduction of a premixed pilot as second step in 2006. Both together resulted in a significant reduction of the NOx emissions of the system. In a third step, an aerodynamic burner modification was introduced in 2007, which improved the thermo-acoustic stability of the system towards higher turbine inlet temperatures and adapted to fuel preheating to allow for increased cycle efficiency. All three features together have been released as package in 2010 and to date accumulated more than 50,000 operating hours (fleet leader 24,000).This paper reports upon the steps towards this latest design status of the SGT5-4000F and presents results from typical focus areas of lean premixed combustion systems in gas turbines including aero-dynamical optimization, fuel/air mixing improvements and cooling air management in the combustor.Copyright © 2013 by Siemens Energy, Inc.