In this paper, a Fiat Avio 701F gas turbine re-design process is presented. This already tested gas turbine has been modified, for a particular re-powering application: a reduction in the net power production is required, whereas efficiency and exhaust temperature have been improved by mean of increased hot gas temperature at the first nozzle inlet section. Consequently this re-powering solution clearly requires consistent re-design efforts to satisfy specific plant operating conditions.
The gas turbine power output has been tuned to the required value by reducing the air inlet mass flowrate; the combustion chamber setting has been modified with particular attention to the control of pollutant emission level. The increase of inlet stator turbine temperature necessitated a complete review of the three cooled turbine stages. The aim of greater overall efficiency with inlet and exit turbine temperature increase also involved the introduction of a new blade material. For design tool flexibility the blade cooling design procedure has been improved making better optimization of the cooling system possible.
In this paper a detailed description of the several gas turbine modifications with particular attention to the blade cooling design procedure and to the corresponding simulation results is reported. The modifications developed could also be introduced on the new version of the 701F, at full power capability, in order to get better efficiency and power.