No abstract

No abstract

The lean premixed combustion system was scaled from Siemens 60Hz engine application and optimized for implementation in the new SGT5-8000H 50Hz engine. The Siemens H-class engine is air cooled, uses a pressure ratio of 19:1 and is designed to achieve an efficiency of >60% efficiency in combined cycle operation. This improved dry low NOx system is of can annular type and consists of 16 cans in the SGT5-8000H. It was developed and tested in a full scale, high pressure rig test program. The single can high pressure rig simulates closely the flow conditions upstream of the combustor in the SGT5-8000H midframe and downstream of the combustor at the turbine inlet. The combustion system uses 5 fuel stages which allow flexible tuning over the whole range of engine operation conditions (ignition, idling, part- and base load). The system is designed to operate over a wide range of fuel quality and preheat temperatures. The test program is carried out over multiple years and encompasses rig / engine tests. This paper describes the combustion system in more details and the testing methodology. The test rig results showed that the performance targets are fully achieved in terms of emissions and operational requirements. Furthermore, the development / validation program will continue to reduce emissions through extended programs for future engines.

A new approach to calculate the mixture statistics in multi-injector burner systems from a single injector data base is presented in the paper. In such systems, the mixture quality is highly sensitive to the flow rate and the skewness of the inflow velocity profile. To determine the mixture fraction statistics from these two parameters for a particular injector in a multi-injector configuration, O-POD is suggested using results from RANS-CFD as the observable. The O-POD mixing database is determined experimentally from two setups: First the mixture quality in a single injector at ideal inflow conditions is studied. Then the same injector type is investigated in a generic multi-injector burner system (MIB). To characterise the mixture quality, the mixing probability mass function (PMF) at the injector exit is measured by means of LIF and high speed imaging. The data obtained for both the single injector under ideal inflow and the MIB are presented. These studies of the mixture behaviour reveal that an asymmetric inflow velocity profile leads to a significant increase of unmixedness, which is seen as a negative skewness of the mixing PMFs. This effect becomes stronger at higher momentum flux density ratios due to the higher penetration depth of the fuel jets. The application of the O-POD to the database shows that the PMF can be accurately modeled with only 3 modes.

The newest Siemens gas turbine family has already been well received by the market. Nevertheless, the market drives continuing development of the family and the combustion system. Central focus is put on further increasing reliability and component lifetime and on increased inspection cycles, as well as increasing the engine power output and efficiency, which is directly linked to higher turbine inlet temperatures. Increasing attention, however, is given to the flexibility concerning fuel quality and according fluctuations. Additionally, more and more strict emission requirements must be considered. This paper especially reports on demonstration of the capability of the Siemens gas turbines with an annular combustion system to fulfil the requirements for the highest operational flexibility. Thus, the combustion system has been tested and qualified for the highest operating flexibility with special fuel requirements such as burning Naphtha, Light Oil #2 and Natural gas with an extremely wide range of heating values as well. Also special operation modes such as fuel changeover, fastest load changes for island grid operation, frequency response and load rejection require this highly flexible combustion system without any hardware exchange. In different frames when fired with natural gas, base load is reached with the NOx emissions ranging well below 25 ppmvd, confirming the high potential of this advanced hybrid burner. In liquid fuel operation, dry NOx emissions of 75ppmvd were demonstrated but by injecting fuel / water emulsion NOx emissions were reduced to below 42 ppmvd with different liquid fuel qualities. Combustion dynamics, unburned Hydrocarbons, CO and soot emissions remained always below the required limits.