ДЕМПФИРОВАНИЕ КОЛЕБАНИЙ ОХЛАЖДАЕМЫХ ПОПАРНО БАНДАЖИРОВАННЫХ РАБОЧИХ ЛОПАТОК ТУРБИН

Abstract

The cooled turbine blades are the parts that determine the reliability and service life of a gas turbine engine. As is known, most cases of engine failure are related to the destruction of turbine blades. Turbine blades during operation experience high thermal stresses, the stresses from centrifugal and gas forces, as well as dynamic stresses. This paper presents methods for ensuring an acceptable level of dynamic stresses in turbine blades. One of the most effective methods is considered in more detail - pairwise shrouded cooled turbine blades. The effectiveness of the damping of such working blades depends on the guaranteed contact of the contact surfaces of the flanges of the shanks and banding shelves and the optimality of the shroud connection. As the object of the study, we chose pairwise shrouded turbine blades from the engine, on which there were several cases of destruction of the turbine blades. To assess the optimality of the bandage connection of the working blades under study, a scheme has been developed for calculating the force acting on the contact surfaces of the banding shelves. According to the developed scheme, calculations were made of the forces acting on the contact surfaces of the retaining shelves, both of the investigated working blades, and similarly pairwise shrouded cooled turbine blades, developed by SE «Ivchenko-Progress». After calculating the force acting on the contact surface of the retaining shelf, the ratio of the received force to the parameters of the feather profile, such as chord and CMAX, is calculated. According to the data obtained, a graph of the dependence of the voltage in the blade on the relative force acting on the contact surface of the retaining shelf was plotted. The analysis of the obtained graph made it possible to conclude that there is an optimal force at which dynamic stresses will be acceptable. However, since a small sample of pairwise shrouded cooled turbine blades is presented, it is necessary to continue the work on determining the criteria for optimality of the shroud linkage and on clarifying the resulting relationship.