FIELD: motors and pumps.
SUBSTANCE: group of inventions refers to the rotors of compressors and fans of fifth-generation aviation gas turbines with compressor impellers manufactured using the "blisk" technology, and fan impellers with wide-chord or wide-chord hollow blades with dampers for damping the vibrations of the blades of these wheels. Term "twin" here is applied to the connection of two impellers of a rotor of a turbomachine, in the structural element of one of which the proposed damping device is located, which suppresses oscillations of the working blades of the other wheel. Twin can consist of two blisks, glare and a single impeller with several steps, blisk and a "classic" impeller with locking fasteners of blades to the disk and two "classic" wheels. Note that each rotor impeller with damping vibrations of working blades with the proposed damper, except for the wheels of the first and last stage, can be part of two sparks. Rotor of the HPC is proposed, consisting of a twin of two blisks – first and second stage impellers, twin from the blisk of the second stage and the "classic" third-stage wheel and the blisk from the "classic" third-stage wheel and the single wheel from the fourth to the sixth step and from the disc with the teeth of the labyrinth seal. And the blisk of the first stage is made in one piece with the ring with the teeth of the labyrinth seal. Blisk of the second stage – with a ring with the teeth of a labyrinth seal and a flange for fixing to the blisk of the first stage and with the rotor shaft of the HPC, and the "classic" wheel and single wheel – with rings with teeth of the labyrinth seal and a flange for fastening to the blisk of the second stage or the wheel of the third stage. Blades are mounted on the "classic" third-stage wheel with the help of the groove "swallowtail" and fixed from the axial displacement by a thrust ring attached to the front end of the rim of the third stage disc and the flange of the second twin wheel. Blades with the fourth to the sixth stage of the HPC rotor are installed on a single impeller HPC rotor in three profiled ring grooves. Platforms of these blades fit tightly to each other, ensuring reliable fixation of the blades in a tangential direction. At the blades of the first wheel of each twin of the rotor of the HPC, those at the blades of both blisks and the "classic" impeller of the third stage, the feather is made without a quadrangular fragment in the form of a trapezoid or a rectangle with one side of which is the trailing edge of the feather of the blade. At the blade tip, the inner angle between the sides serving as the upper base and the side of this quadrilateral is rounded by a radius, and this angle is equal to or greater than 90°. Rim of the disc of this blisk or this "classic" wheel is made only on the length of the base of the blade of the blade. Length of the blade lock of the "classic" wheel is equal to or less than the length of the rim of the disc and the blade lock does not protrude from the ends of the rim. Flange has an annular groove concentric to the axis of the wheel. In the outer shelf of this groove, the radially equal reciprocating blades of the first twin wheel, to which this wheel is attached, are formed. In the annular groove with interference on the shelves of the groove, an annular elastic-hysteresis element of structural damping is inserted, and in the radially located grooves with their bases without a gap or with a very small gap along the walls of the groove, for example with a gap less than 0.02 mm, friction elements consisting of a base in the plan precisely repeating the shape of the groove are inserted up to the stop with the bases in the elastic-hysteresis element, and a feather having a geometric form of a quadrilateral withdrawn from each working blade, with cross sections that accurately repeat the geometric shapes of the cross sections of the seized fragment of the blade of the blade. Second twin wheel is fixed in such a way that the feather of each friction element accurately takes the place of the seized fragment of the blade of the blade. In this case, a desired load amount is created that presses the friction element against the side of the blade of the blade contacting the upper end of the feather of the friction element, created due to the large elastic deformation of the elastic-hysteresis element, completely or not fully straightening it, and in all operating conditions of the engine these elements are additionally pressed against each other by a centrifugal force created by the mass of the friction element. Between the end of the rim of the first twin wheel and the counter faces of the bases of the friction elements, the interference is zero or there is a small gap, for example 0.01÷0.02 mm. Thickness of the base of the friction element and the shape of its outer surface are such that in the assembled twin, the outer surface of the base of the friction element constitutes one surface with the outer surface of the inner ring HA of the second twin wheel. Height of the feather of the friction element is chosen such that its upper end and the reciprocal side of the feather of the blade contacting it are located outside the nodes of the dangerous forms of vibration of the blade, at the place of large amplitudes of the displacements of its feather, at which there would be a mutual slip with dry friction of the upper end of the friction element and the reciprocal side of the feather blade. Rubbing with dry friction of the surface of the system "disk – working blades – damping devices" are covered with a wear-resistant coating, for example, silvering. Optimal and final settings of the system "disk fragment – working blade – damping device" and the dimensional parameters of the damping devices are determined from the virtual experiment.
EFFECT: advantages of all the proposed damping devices that ensure their high efficiency are: possibility of using friction elements with structural parameters in all practical cases, with bending stiffness of the same order with the bending stiffness with which it contacts; application of elastic-hysteresis elements of structural damping with the best UFH and high performance characteristics – strength, wear resistance and resource; calculation: the possibility in the near future of determining the optimal parameters of damping devices from a virtual experiment to study the oscillations of the system "disk fragment – working blade – damping device"; versatility: the possibility of using the proposed devices in the rotors of fifth-generation aircraft engines for damping vibrations of blisk working blades and "classic" wheels; and, apparently, in the case of blisks, the proposed solution is still the only technically feasible solution.
14 cl, 22 dwg
