Measuring the thermodynamic performance of steam turbines in Brayton/Rankine combined cycle plants

摘要

A steam turbine operating in a typical combined cycle has an operating configuration drastically different than that of a steam turbine in operating in a pure Rankine cycle. Further, many key operating parameters of typical combined cycle steam turbines, in particular flow rates, are in different regimes than that experienced in pure Rankine cycle steam turbines. Piping geometries are also on a much different scale for typical installations. Determining the thermodynamic performance of steam turbines in combined cycle operation poses challenges to the power plant performance test engineer which have not been thoroughly documented in a single reference. The authors intend with this paper to detail the major differences between determination of the performance of a steam turbine in conventional Rankine cycle regenerative operation in a fossil fueled power plant, and of a steam turbine in a typical Brayton/Rankine combined cycle power plant. Both cogeneration and non-cogeneration plant configurations are considered.