RU119414U1 - TWO-STAGE CENTRIFUGAL COMPRESSOR - Google Patents

Abstract

A two-stage centrifugal compressor for a gas turbine engine, mainly aircraft, containing two centrifugal impellers, characterized in that each centrifugal wheel is mounted on its own shaft, one of which is the leading and the second driven, the ends of the shafts - pins - rest on bearings and are interlocked by a connecting spring , and for clutching and transmitting torque from the wheel of the second stage to the wheel of the first stage at the front and rear ends of the spring there are external splines and an external annular groove, the rear journal of the shaft of the centrifugal wheel of the first stage and the front journal of the shaft of the centrifugal wheel of the second stage contain internal splines and an internal annular groove corresponding to the outer splines and the outer annular groove at the ends of the spring, and the outer annular grooves of the spring and the inner grooves of the shaft trunnions are filled with balls, which, under the action of centrifugal forces, are displaced from the compressor axis and connect the shaft journals with the spring, forming latching connection during operation, automatically disengaged when stopped.

Description

The utility model relates to compressors of aircraft gas turbine engines.

The compressor is the main element of an aircraft gas turbine engine (GTE).

Known multistage radial compressors (US patent No. 5,490,760, US patent No. 4,579,509), which includes a flow part where compressible air flows, impellers with many blades that are located in the flow part and are able to rotate with the impeller around the axis of the drive shaft.

Known two-stage radial compressor of a gas turbine engine (GTE), located on one shaft with a turbine that drives the compressor (US patent 4,993,220, 1991).

A feature of the known compressor designs, consisting of two centrifugal stages, is that both centrifugal wheels are located on the same shaft of the gas turbine engine generator.

A gas turbine engine is known, for example, an aircraft turbojet or turboprop engine containing a compressor, the shaft of which is driven by a turbine shaft (RF application No. 2007114108). The compressor shaft and the turbine shaft are connected by a device in which the end of the drive shaft contains straight slots and enters the covering part of the driven shaft containing straight slots corresponding to the splines of the drive shaft. The splined area of the driven shaft contains at least one cylindrical part with greater torsional flexibility and located near the longitudinal end of the splined area. In a more flexible part, the splines of the driven shaft and / or drive shaft are machined so as to eliminate any contact between them when transmitting torque.

This technical solution is aimed at connecting the compressor shaft and the turbine shaft. It does not concern the connection of centrifugal wheels located on the same shaft of the gas turbine engine generator.

A two-stage centrifugal compressor with a single-shaft layout is characterized by complex and time-consuming work on detuning the rotor from critical vibrations in the entire range of operating rotation frequencies, which sometimes forces to partially leave the zones of dangerous rotation frequencies of the gas generator rotor.

In addition, the single-shaft arrangement of a two-stage centrifugal compressor requires laborious installation work due to the installation of elastic-damper rings in the shaft bearing units, which are difficult to manufacture and require the supply and removal of oil to them. Assembly-disassembly of a single-shaft centrifugal compressor with all its relative simplicity is very laborious, which makes repair work more difficult.

The utility model is based on the task of improving the detuning of the rotor from critical vibrations over the entire range of operating rotation frequencies while reducing the complexity of installation work of a two-stage centrifugal compressor.

EFFECT: output of critical rotational speeds at rotational speeds higher than the maximum design rotational speed, reducing the complexity of installation.

The problem is solved in that a two-stage centrifugal compressor for a gas turbine engine, mainly an aircraft, contains two centrifugal impellers, each centrifugal wheel is mounted on its own shaft, one of which is the driving one, and the second driven, the shaft ends - axles - are supported by bearings and are coupled connecting spring, moreover, for the coupling and transmission of torque from the wheel of the second stage to the wheel of the first stage at the front and rear ends of the spring are made external splines and out The first annular groove, the rear axle of the shaft of the centrifugal wheel of the first stage, and the front axle of the shaft of the centrifugal wheel of the second stage contain internal splines and an internal annular groove corresponding to the external splines and the external annular groove at the ends of the spring, and the external annular grooves of the spring and the internal grooves of the shaft axles are filled with balls which, under the action of centrifugal forces, are displaced from the axis of the compressor and connect the shaft pins with a spring, forming a lock connection during operation, which automatically disengages at a stop. the front and rear ends of the spring have external slots and an external annular groove, the rear axle of the shaft of the centrifugal wheel of the first stage and the front axle of the shaft of the centrifugal wheel of the second stage contain internal splines and an inner ring groove corresponding to the external splines and the outer ring groove at the ends of the spring, and the outer ring the grooves of the spring and the internal grooves of the shaft pins are filled with balls, which under the action of centrifugal forces are displaced from the compressor axis and connect the shaft pins with the spring, about by loosening the locking joint during operation, automatically disengaged when stopped.

The utility model is illustrated by the description and drawing, which shows a fragment of a two-stage centrifugal compressor of an aircraft engine with a node connecting two rotating shafts of the first and second centrifugal wheels according to the utility model (circuit diagram).

A two-stage centrifugal compressor contains two impellers - the first centrifugal wheel 1 (1st stage) and the second centrifugal wheel 2 (2nd stage) installed in the main body, forming a flow part containing the blade crowns of radial diffusers.

According to a utility model, the centrifugal wheel 1 is mounted on its own shaft 3, and the centrifugal wheel 2 is mounted on the shaft 4.

Each shaft 3 and 4 at the ends contains trunnions - front 10 and rear 11, on which thrust bearings are installed.

On the front axle 10, roller bearings are installed - a supporting roller bearing 6 at the end of the shaft 3 and a supporting roller bearing 8 at the end of the shaft 4.

Angular contact bearings are installed on the rear pins 11 — an angular contact bearing 5 at the end of the shaft 3 and an angular contact bearing 7 at the end of the shaft 4.

The shafts 3 and 4 are interconnected by a special connecting spring 9.

For clutch, shafts 3 and 4 and connecting spring 9 contain splines and grooves (not shown in the drawing). On the front of the spring 9, external slots and an outer ring groove are made, on the rear part there are also external slots and an outer ring groove, the rear axle 11 of the shaft 3 of the centrifugal wheel 1 of the first stage contains internal splines and an inner ring groove corresponding to the external splines and the outer ring groove springs 9 (front end), the front axle 10 of the shaft 4 of the centrifugal wheel 2 of the second stage contains internal slots and an inner ring groove corresponding to the outer slots and the outer ring groove e at the rear end of the spring 9.

The spline connections of the spring with the centrifugal wheels provide the transmission of torque from the second wheel to the first.

The inner annular grooves of the axles 10 and 11 of the centrifugal wheels 1 and 2 are filled with balls (not shown) connecting the rear axle 11 of the first wheel 1 with the front end of the spring 9 and the rear end of the spring 9 with the front axle 10 of the second wheel 2.

During operation of a centrifugal compressor, the air stream enters the impeller along the axis of the engine, and the flow rotates in the radial direction in the impeller. When the centrifugal wheels rotate, the balls in the grooves of the springs and trunnions under the action of centrifugal forces are displaced from the compressor axis, forming a lock connection of the spring with the trunnions of centrifugal wheels. The locking ball connection of the spring with the centrifugal wheels provides a summation of the axial force of the wheels and eliminates the need for setting the elastic-damper rings in the bearing nodes of the shaft,

Locking clutch of centrifugal wheels is formed and acts during operation of a centrifugal compressor. When the compressor stops, the centrifugal wheels stop rotating, the balls are displaced to their original position to the compressor axis and the lock connection is automatically disengaged.

The utility model makes it possible to derive critical rotor speeds 20-25% higher than the maximum calculated compressor speed without the above setting of elastic-damper rings in bearing assemblies that are difficult to manufacture and require the supply and removal of oil to them.

Thus, the utility model provides the output of critical rotational speeds at rotational speeds higher than the maximum design rotational speed, does not require the installation of elastic-damper rings in the bearing assemblies, that is, it improves the detuning of the rotor from critical vibrations over the entire range of operating rotational speeds while reducing the complexity of the two-stage installation work centrifugal compressor.

The utility model can be used in aircraft engines, as well as in ground-based power plants, in special plants that pump gas mixtures in main gas pipelines, as well as in engines for land and water transport.

Claims (1)

A two-stage centrifugal compressor for a gas turbine engine, mainly an aircraft one, containing two centrifugal impellers, characterized in that each centrifugal wheel is mounted on its own shaft, one of which is the driving one and the second driven, the shaft ends - axles - are supported by bearings and are connected by a connecting spring moreover, for the coupling and transmission of torque from the wheel of the second stage to the wheel of the first stage at the front and rear ends of the springs are made external splines and an outer annular the mouth, the rear axle of the shaft of the centrifugal wheel of the first stage and the front axle of the shaft of the centrifugal wheel of the second stage contain internal splines and an inner ring groove corresponding to the external splines and the outer ring groove at the ends of the spring, and the outer ring grooves of the spring and the internal grooves of the shaft axles are filled with balls under the action of centrifugal forces, they are shifted from the compressor axis and connect the shaft pins to the spring, forming a locking connection during operation, which automatically disengages when stopped.