FIELD: aviation.
SUBSTANCE: group of inventions relates to aircraft gas turbine engines and gas turbine plants, namely to devices for controlling radial gap between ends of rotor blades of compressor or turbine stage and stator of first circuit of double-flow gas turbine engine. For use in one and two stages of compressor, including for HPC, and turbine, at stages of which stator is not cooled by compressed air supplied due to any stage of compressor, and NA, located before and behind impeller step, are not connected with rotor supports, disclosed is an automatic device for thermomechanical control of a radial gap between ends of rotor blades and a stator of a compressor and turbine of a double-flow gas turbine engine, device comprises segments made in a ring, enclosing rotor working blades of compressor stage or turbine with radial gap at ends of blades, and with gaps between ends of adjacent segments, radially located rods connected to these segments, positioning mechanisms connected to rods and displacing rods and segments in radial directions, towards longitudinal axis of engine or from it, characterized by that rods are hermetically and rigidly fixed in segments, each segment is made in form of VR segment of compressor or NA of turbine, segment of outer ring of which is made with such width that its part, free from blades VR or NA, with given initial radial gap encloses working blades of mating sector of rotor, and its segment of internal ring of VR or NA covers with given initial radial gap in mating sector of rotor labyrinth seal teeth, and segment of the outer ring segment has radial section in form of channel bracket, and segments themselves are located in annular cavity of step body section, formed by two vertical annular flanges, one of which is made integral with step body section, and the other is fixed in the same flange joint, as body section, wherein segments are arranged with minimum possible gap on lateral sides of segment, they are made in ring with possibility of displacement in radial directions relative to annular flanges and free thermal expansion, with gaps along their ends located along radial directions, wherein value of each of these gaps is selected as minimum possible, providing their allowable value in all modes of engine operation, with all permissible displacements of segments in radial directions, and on outer surface of body section there are tightly fixed supports, and rods pass into engine second circuit through central holes in supports with possibly less gap, but such that excludes their wedging in all modes of engine operation, and the possibility of the segment skewing relative to the axis parallel to the longitudinal axis of the engine located in the radial plane passing through the attachment point of the rod to the segment, leading to an emergency situation – collision of the working blades with the end of the segment, first in rotor rotation direction, or to working blades into segment, or to inadmissible reduction of step efficiency, support height and rod length are made such that they do not reach inner surface of engine second housing, and the support height is such that both inner cylindrical surfaces of the support, on which the rod rests in case of skewing, are spaced along the axis of the rod at a distance between the initial cross-section of one support surface and the end of the other, approximately equal to the length of the greater arm of the segment, measured from the attachment point of the rod to its end face, and connection of rod and support is sealed by two pairs of piston rings located in annular grooves of support, wherein in each pair of piston rings cuts of said rings are located diametrically opposite, and to the outer housing of the second contour are welded butt-to-back flat support platforms, or flat support platforms are made on the butt-end welded to the outer housing of the second circuit ring, and bases are installed on platform, displacement of which relative to sites in direction of engine longitudinal axis is limited by value of radial gap between rod and hole in site, through which passes cylindrical support screwed on rod, and value of which is greater than or equal to value of maximum mutual slip in direction of longitudinal axis of base and platform engine, which is caused by difference of thermal expansions of stators of second and first circuits of engine, displacement of the base in a direction perpendicular to the longitudinal axis of the engine is limited by the value of the gaps between the guide supports and the base ends, which is selected as low as possible, but such that excludes jamming of the base in the stator working deformations of both engine circuits, and guide supports themselves have L-shaped shape and using pins, screws, lock washers are fixed on support sites parallel to longitudinal axis of engine and their shelves are pressing bases to support sites, on bases coaxially with supports of rods, fixed on body section, supports are tightly fixed, and on rods are screwed cylindrical supports, under which on rods there spacing plate and elastic split safety washer are installed,and the thickness of the spacing plate is selected so that when the support is turned up to the stop, the eye, made on the support end, is located strictly parallel to the longitudinal axis of the engine, and these cylindrical supports of rods with a gap, which allows base slippage relative to support platforms at thermal expansions of stators of the first and the second engine circuits, through holes in support platforms and with minimum possible gap, excluding their jamming, through holes in bases and central holes in supports fixed on bases, go into engine nacelle to height, providing assembly of lever, and the connection of the support screwed on the rod, and the support fixed on the outer housing of the second circuit, is sealed by a pair of piston rings located in the annular groove of one of these supports, wherein sections of said rings are located diametrically opposite, and each positioning mechanism consists of first or second type lever, including support fixed on base, lever itself made in form of parallelepiped or boomerang, with rectangular through slot made along its length, fixed on axis embedded in support, with possibility of rotation relative to this axis, and tie rod fixed on thread with interference in boss, made on outer surface of body section or adjacent to it body section, and location of this boss is selected in such plane perpendicular to longitudinal axis of engine, in which thermal expansion of housing section in radial directions, in which there are bosses, is so different from thermal expansion in radial directions of outer housing of second circuit, so that length of lever arm, to which the rod is hingedly fixed, was constructive and at that provided optimum value of radial gap along ends of working blades of stage at cruise mode of engine operation and sufficiently good values of this gap on small gas and subsequent injectivity at aircraft departure for second round, tie rod length is made such that tie rod does not reach inner surface of outer housing of second circuit, and on each tie rod a cylindrical support is screwed on, under which a spacing plate and a resilient split safety washer are installed, and the thickness of the spacing plate is selected so that when the cylindrical support is screwed on against the stop, the eye made on the support end face is located parallel to the engine longitudinal axis and the initial radial gap along the working blades ends of the step is of the specified value, and these cylindrical supports with the same gap as cylindrical supports screwed on the rods, pass through the holes in the support sites and with the minimum possible gap excluding jamming, exit through the holes in the base and central holes of the tie rod supports, tightly fixed on the base, into engine nacelle, and connection of cylindrical support screwed on tie rod and support fixed on base, is sealed by a pair of piston rings located in annular groove of one of these supports, wherein sections of these rings are located diametrically opposite, and hinged connection of rods and tie rods with levers, providing their displacement strictly in radial directions to the longitudinal axis of the engine and from it, is performed by means of axes, with tension of the cylindrical supports fixed in the eye holes, arranged with zero or minimum possible gaps on their lateral sides in the levers slots, and freely passing through through slots in the side walls of the lever, wherein the width of each slot is equal to the diameter of the axis, and its length is such that when the levers are rotated, the axles are freely slid about the sides of the slot, through which the lever is in contact with the axes, and all axes in holes, in which they are fixed, are additionally locked against their displacement and rotation by lock screws, wrapped in eyes, and parts located in engine second circuit – supports, through which rods and tie rods pass, are closed by fairings made in the form of blades equally distributed in circumferential direction, and device parts located in engine nacelle are closed by jackets, and to use device on two adjacent stages it is simply replicated except for tie rods, casings and fairings, but with other required design parameters, which can vary both quantitatively and qualitatively when used in steps of devices with levers of different types, and wherein tie rods, casings and fairings are made common for devices of both stages.
EFFECT: advantage of the proposed devices is their structural simplicity – there are no power drives, displacement sensors, multichannel device for reading sensor readings, electric connections, including with on-board computer, linking ring and transfer links made in the form of ball hinges, which connect this ring with power drive and positioning mechanism.
15 cl, 26 dwg
