How Many Turbine Stages?

This article discusses various stages of turbines and the importance of having more stages in turbine design. The article also highlights reasons that determine the designer’s choice to select the number of turbine stages for a given design of gas turbine. The highest performance turbines are defined by lower work requirements and slower velocities in the gas path. The fundamental factors determining performance might be relegated to only two factors: demand on the turbine and axial velocity. Aircraft engine technologies drive new initiatives because of the need to increase firing temperature and dramatically improve efficiency for substantially less weight. Also, the expansion across each stage determined the annulus area so that the optimums implied by the Pearson chart were largely ignored in the article. Developments in aircraft engine gas turbines have forced heavy frame gas turbines’ original equipment manufacturers to rethink many historical paradigms.