The undertaken research deals with the analysis of the expansion line through cooled (and uncooled) stages of an axial gas turbine.
A one-dimensional model has been developed to investigate the effects of blade cooling: its architecture refers to the stage mean line and considers the velocity triangles. The procedure matches the requirements of reliability and flexibility needed in the field of thermal cycle analysis.
The model allows the evaluation of the coolant mass flow required for each row and a full estimation of the cooled expansion line for different cooling techniques (convective, thermal barrier coating and film cooling) and fluids (air, steam carbon dioxide and helium). The model takes in consideration the effects of discharging coolant at the trailing edge or at the hub of the blade. This model can investigate the impact of different cooling methods and alternative coolants on the expansion line.
Two different code has been realized to simulate the expansion: the first (EOLO) estimates coolant mass flow and the second (NETTUNO) evaluates the expansion line as is explained in the following flowchart; while the second figure shows an example of film cooling simulation.
In the thirst figure the effect of different blade cooling techniques on mass flow cooling air is underlined; while, the last one, shows the influence of using unconventional fluids.