Patent RU-2702063-C2 (RU)
Title: Device for mechanical control of radial clearance between ends of rotor blades and stator of compressor and gas turbine engine turbine, method of controlling radial clearance between ends of rotor blades and stator of compressor and gas turbine engine turbine
Inventor: ESKIN IZOLD DAVIDOVICH
IPC: F01D11/22
Filed: 2017-10-23
Granted: 2019-10-03
Abstract: FIELD: machine building. 
     SUBSTANCE: group of inventions relates to aircraft gas turbine engines and gas turbine plants, namely to mechanical devices for regulating radial clearance between ends of rotor blades of compressor or turbine stage and housing of gas turbine engine. Disclosed is mechanical device for controlling radial clearance between ends of rotor blades and stator, comprising section of outer housing, fixed on outer housing, positioning mechanisms, a ring articulated with all of these mechanisms, segments composed of a ring or two rings enclosing rotor blades with a radial clearance, and each positioning mechanism consists of a rod installed with possibility of displacement along the longitudinal axis of the mechanism to the longitudinal axis of the engine and from it, pairs of elements, one of which is fixed on the end of the rod, and displacement of the other element relative to it causes displacement of the rod along its longitudinal axis, an elastic element creating a force of elastic pre-tension, acting on the rod along its longitudinal axis, and each segment is fixed on the other end of the rod, and in annular empty cavities of outer casing section there are external rings HA compressor or CA of turbine, which are fixed with their protrusions in annular grooves made in thickened rings of annular flanges of section, and ring or two rings made of segments. In annular space, in which segments are arranged with minimum possible clearance 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 to be zero or minimum possible, providing their allowable value in all modes of engine operation, with all permissible displacements of segments in radial directions. Segments in their middle radial section are fixed on rods of positioning mechanisms, which are made hollow, and inside all or part of rods there fixed are sensors, which measure radial gap. On outer surface of section of external housing there are support platforms, on which supports are tightly fixed, and rods pass into the second circuit of engine through central holes in sites and supports. Connection of rod and support is sealed by two pairs of piston rings located in annular grooves of support, besides, in each pair of piston rings sections of these rings are located diametrically opposite. On the free end of each support there is a flange, the supporting flat surface of which is perpendicular to the longitudinal axis of the rod, and on sides of flange there are guides located parallel to longitudinal axis of engine. Moving wedge-like elements with wedge angle defined by its tangent equal to 0.1÷0.03. In each of said wedge-like elements in the direction of the engine longitudinal axis there is a through slot which provides the required displacements of the wedge-shaped element and through which the rod passes. On the surface, by which the wedge-shaped element rests on the support flange, there are crosswise made two blind slots with the width providing the required area of four rectangular support platforms on this surface. In the wedge-shaped element, in the end perpendicular to the through slot, there is a threaded hole, and on its lateral sides, parallel to the longitudinal axis of the engine, in the middle of the sides in the tangential direction there are two consoles ending with rectangular platforms, the upper surfaces of which form wedges with the same inclination angle as the wedge-shaped element. To ends of consoles, with their coverage, to these rectangular sites are attached brackets-stops so that inner surface of each of brackets, made with same slope, as wedge of wedge-like element, forms with wedge of rectangular platform groove with rectangular cross-section, inclined to plane perpendicular to longitudinal axis of rod, with same inclination as wedge of wedge-like element. On the threaded end of each rod with tubular cylindrical thread the support is screwed in, at the rods, in which the sensors are fixed, additionally fixed from turning by the elastic split washer and the cover, screwed on the same thread, sensor tube, which is connected to the sensor, through which the sensor cable is connected, passes through the central hole in the cover with zero clearance, and the gap between the tube and the cover is sealed with a sealing ring, or on these rods, as well as rods, in which sensors are not fixed, cover and resilient split washer are not installed, and rod end is left free. Support screwed on the rod is made as the second wedge-like element supported by two or four rectangular platforms formed by one or two crosswise slots on the wedge-like surface of the support, on mating wedge-shaped surface of the first wedge-shaped element. On lateral sides of this support, parallel to longitudinal axis of engine, in the middle of sides in tangential direction are made two cantilevers, ending with flat flanges inclined to plane perpendicular to longitudinal axis of rod, with the same inclination as the wedge-shaped element wedge and entering the slots formed by the retainer brackets, with a clearance on each of the flange sides, measured in the longitudinal axis direction of the rod, equal to 0.1÷0.2 mm, or at the end of each segment, first located in rotation of the rotor, from the surface enclosing the rotor working blades, the chamfer is drawn out, which is outlined by the local curve smoothly changing into the surface enveloping the working blades, with one leg 0.3÷0.5 mm and other leg 15÷30 mm, and clearance on each side of flange, measured in direction of longitudinal axis of rod, in this case is equal to 0.2÷0.5 mm. To this support symmetrically to the rod there are fixed central supports of two springs, made in the form of multilayer pack compressed by distributed load, assembled from steel, hardened or cold-worked, polished tapes, made from stainless steel, coated with wear-resistant coating, and the spring by its end supports are fixed in the second circuit on the outer housing section so that the longitudinal axis of the package is located perpendicular to the longitudinal axis of the engine, and at that, due to elastic deformation of pack there created is required force acting on rod and pressing wedge-like element fixed on rod to movable wedge-like element. 
     EFFECT: design simplicity, repairability, good mass characteristic is achieved, jamming of segments and rods of the positioning mechanism is eliminated. 
     14 cl, 26 dwg