Joint aerodynamics and strength optimization of a single-stage uncooled turbine with a shroud platform

The paper presents the results of solving the complex problem of improving rotor wheel reserves and efficiency of a single-stage axial free turbine of a small-sized turboshaft engine using multidisciplinary optimization methods. The working blade of the turbine has a shroud platform. A relatively thick strut is fitted before it. Analysis of the initial version of the turbine's RW showed that it has a satisfactory margin of load capacity, but the margin of local strength is lower than acceptable. In order to eliminate the identified problem, the task of rotor wheel adjustment was solved at the first step only according to strength requirements without taking into account aerodynamic processes. As a result, variants of the turbine blade were obtained, which satisfied the strength restrictions. They were used as starting points for solution of a complex optimization problem with consideration of aerodynamic and deformation processes. As a result of the work it was possible to increase efficiency of free turbine by 0,3 % at fulfillment of strength requirements.