Patent RU-2704056-C2 (RU)
Title: Turbine of double-flow gas turbine engine with active thermal control of radial clearance in turbine, method of active thermal control of radial clearance in turbine of double-flow gas turbine engine
Inventor: ESKIN IZOLD DAVIDOVICH
IPC: F01D11/24
Filed: 2017-06-07
Granted: 2019-10-23
Abstract: FIELD: machine building. 
     SUBSTANCE: group of inventions relates to aircraft gas turbine engines and gas turbine plants, namely to mechanical devices with thermal control of radial clearance between ends of rotor blades of compressor or turbine stage and housing of gas turbine engine. Single-stage high-pressure turbine of double-flow gas turbine engine with active thermal control of radial clearance in turbine includes one cooled stage with nozzle device and turbine rotor with cooled impeller, as well as a turbine stator, having two turbine housings with cavities between them, into which compressed air is supplied due to the last stage of the high pressure compressor, and a radial clearance control system comprising an annular insert, above the turbine wheel, enveloping the turbine rotor blades with an annular radial gap and elastically and hermetically attached to the parts forming the turbine inner housing, heater enveloping annular insert with possibility of its heating, air intake, cooling air flow rate controller with drive, onboard computer and sensors, and heater. Flow controller drive and transducers are electrically connected to the on-board computer. Annular insert is made hollow and annular projections made on its lateral sides, with tension is fixed with possibility of thermal expansion in mating annular grooves of vertical wall and flange, made on inner part of outer housing of HPT, nozzle assembly with annular projections is also tightly fitted in reciprocal annular grooves of vertical wall and housing of combustion chamber, in which and in vertical wall there are holes equally distributed in circumferential direction, through which secondary air is supplied from combustion chamber in cavity above nozzle device and annular insert. Disk and working blades of the HPT wheel are also cooled by secondary air swirled by the screwing device before entering the disc web. Circular microwave heater, either resistive or inductive, consists of two separate semi-rings made each in the form of a metal housing, inside which a heating element is fixed, and each semi-ring of heater is fixed on annular insert with possibility of radial thermal expansion together with annular insert and tangential thermal expansion relative to annular insert by means of bayonet connection with it and keys located with interference tension in reciprocal slots of bayonets of annular insert and each half-ring in its average cross section. Two branch pipes are screwed into annular insert diametrically opposite with tension along tubular thread, air intake branch pipe for supplying cooling air from the second circuit into inner cavity of annular insert and branch pipe for discharge of this air into the second circuit or for other purposes. Outlet of branch pipes into the second circuit is sealed by piston rings. On each branch the support is screwed up and to this support symmetrically to the branch pipe the central supports of two springs are fixed, made in the form of the multilayered package compressed by the distributed load, typed from steel, hardened or cold-worked, polished tapes made of stainless steel, coated with wear-resistant coating, and the spring by its end supports are fixed in the second outline on the outer housing of the HPT. Air discharge branch pipe is connected to pipeline, at outlet of which there is either normally open or normally closed electro pneumatic valve, and control of radial clearances is carried out by onboard computer commands according to proposed method, or spool distributor with electromagnetic drive, designed so that position of spool adjusting air flow, at cruising mode at altitudes higher than height limit on barostat H, was recorded with the electric drive de-energized, and the heater switching on and off and adjustment of its heating intensity, opening and closing the cooling air supply from the second circuit and intensity of this supply is performed by commands of onboard computer generated by program according to signals of sensors - engine rpm sensor and barostat according to another proposed method, or sensors measuring size of radial clearance along working blades. 
     EFFECT: sufficiently simple, repairable design, with possible quick replacement of worn-out radial clearance control system units, with good mass characteristic, efficient design. 
     15 cl, 17 dwg