RU2808879C1 - Schematic diagrams of gas turbine engine - Google Patents

Abstract

FIELD: gas turbine engines.

SUBSTANCE: kinematic schemes relate to the field of gas turbine engines and power plants implemented according to the scheme of an axial compressor and turbine, using combustion products as a working medium with a primary application in the aviation field. It includes engine housing 1, rear support bearing 2, front support bearing 3, rotor compression force 4, compressor rotors 5, turbine rotor 6, torque transmission rotation elements 7, rotation element separators 8, compressor blades 9 and turbine blades 10, fixed central beam 11. In this case, the method of transmitting torque sequentially from one rotor to another using rotation elements makes it possible to create an engine without a straightening apparatus, by organizing alternately counter-rotation of the rotors with a rotation of the blades on counter-rotating disks by 90 degrees.

EFFECT: alternative gas turbine engines layout enabling: simpler design of power plants; minimization of the weight of the power plant and its dimensions by increasing the efficiency of the entire engine and individual systems; creation of the prerequisites for increasing the service life of power plants by optimizing and reducing the loads on engine components.

2 cl, 5 dwg

Description

The invention relates to the field of gas turbine engines and power plants, implemented according to the scheme of an axial compressor and turbine, using combustion products as a working fluid with primary use in aviation.

A device is known that consists of a compressor and a gas turbine mounted on one common shaft, between which a combustion chamber is located. The compressor forces compressed air into the combustion chamber. In the combustion chamber, compressed air is mixed with fuel, which, when burned, forms excess volume and pressure, which in turn spins the turbine. The turbine spins the compressor through the shaft and the cycle closes. The engine was patented by Frank Whittle (patent No. 347206) and, most importantly, was successfully tested as an aircraft power plant. Since then, this scheme has remained dominant.

The original design of a compressor and a gas turbine mounted on one common shaft was extremely simple and ingenious. But the simplicity of the scheme does not always mean the simplicity of its practical implementation. As the need to increase engine thrust grew, it turned out that the compressor performance (in the initial stages of a centrifugal compressor) was not enough. Then an axial type was proposed in the form of a rotor with blades located along its rim. But for an axial compressor, one stage was also not enough. The logical solution was to add additional stages for stage-by-stage compression. And here the first problem appeared - at the exit from the first stage of the compressor, the air flow twisted in the direction of rotation of the compressor blades and the compression efficiency of subsequent stages dropped critically. This disadvantage of the classical scheme (hereinafter referred to as “KS”) with an axial compressor was solved by placing a straightening apparatus in the air path. A passive device that changes the direction of air flow. A heavy structure that, by throttling the air path, not only converts the kinetic energy of the air flow into useless and even harmful heat at the compression stage, but also accumulates it due to its natural heat capacity.

The kinematic scheme proposed within the framework of this invention solves most of the inherent problems of the above-mentioned classical scheme.

The technical result of this invention is the proposal of alternative layout schemes for gas turbine engines that will allow:

1. Simplify the design of power plants;

2. Minimize the weight of the power plant and its dimensions by increasing the efficiency of the entire engine and individual systems; 3. Create the prerequisites for increasing the service life of power plants by optimizing and reducing loads on engine components.

Scheme No. 1, shown in Fig. 1, and includes an engine housing 1, a rear support bearing 2, a front support bearing 3, position 4 indicates the compression force of the rotors F, compressor rotors 5, turbine rotor 6, torque transmission rotation elements 7, rotation element separators 8, compressor blades 9 and turbine blades 10, a fixed central beam 11. The scheme makes it possible to create an engine without a straightener, by organizing alternate counter-rotation of the rotors with a rotation of the blades on counter-rotating disks by 90 degrees. Alternate counter-rotation of the rotors is realized by transmitting torque from the turbine to each compressor stage not through the shaft, but sequentially, through sets of rotation elements placed between the disks and placed in fixed separators. The elements of rotation can be rollers, disks, wheels and even gears, but balls seem to be the most optimal option. Since in the process of transmitting torque, the axis of rotation of the ball is not fixed and will continuously change due to vibrations, thus making the entire surface of the ball working. In addition, the spherical shape ensures the highest possible resistance to stress. Therefore, in what follows, the elements of rotation are described as balls. The package of disks and balls is compressed with the necessary force, sufficient to ensure the transmission of torque from one rotor to another. Compression can be carried out by any method known from the prior art. For example, a spring, air or hydraulic cylinders. Scheme No. 1 allows you to significantly reduce the total weight of the structure, as well as the speed of rotation of the compressor rotors while maintaining overall performance, since the performance of the compressor will be determined by the sum of the speeds of the rotors rotating in different directions.

In fig. Figure 3 shows an approximate layout option, illustrating the possibility of implementing kinematic scheme No. 1.

It is known that in an axial compressor, due to centrifugal forces, the compression process is concentrated mainly on the periphery of the air path. In the CS, when transmitting torque through the central shaft, the working force is first formed on the end surfaces of the turbine blades, then through the shoulder of the application of force formed by the turbine blade and its disk is transmitted to the shaft, from the shaft again through the shoulder “compressor disk - blade” is transmitted to the working process area . In this case, a “bundle” of power levers arises, creating a huge number of “parasitic” critical stresses. Therefore, the supply of torque in the place where it is actually needed - along the outer contour, implemented in scheme No. 2, is preferable.

Kinematic diagram No. 2, Fig. 2 includes an engine housing 1, a rear support bearing 2, a front support bearing 3, position 4 indicates the compression force of the rotors F, 5 compressor rotors, turbine rotor 6, torque transmission rotation elements 7, rotation element separators 8, compressor blades 9 and turbine blades 10.

When implementing this scheme, the load pattern of the blades changes from tension to compression and the maximum loads shift from the tip of the blade to the sole. This makes it possible to further reduce the weight of the entire structure, allowing a smaller margin of safety to be incorporated into the design of the blades and at the same time increasing their service life.

In fig. 4 shows an approximate version of the layout, illustrating the possibility of implementing a kinematic scheme with transmission of torque along the outer contour. The gas turbine engine (Fig. 4) consists of a housing 1, a rear support bearing 2, a front support bearing 3, a rotor compression drive 4, outer annular compressor rotors 5, turbine rotors 6, torque transmission balls 7, separators 8, compressor blades 9, turbine blades 10, central beam 11, double-sided bulkhead rack 12 with rollers 13 located on it, support bushing for axial positioning of the internal rotors of the compressor and turbine 15, transfer disk 16 and combustion chamber 17. The number 18 indicates the channels of the turbine blade cooling system.

Gas-dynamic processes in a gas turbine engine built according to scheme No. 2 are essentially no different from the CS. This is the same gas-air path with an axial compressor, combustion chamber and turbine. The differences are that the design provides a different, more rational interaction of power plant parts with the air flow. The main feature is the design of the rotors. The proposed technical solution implements a two-support, articulated-movable type of blade arrangement in which each rotor consists of two rings - outer and inner. With grooves in the shape of the cross section of the blade feather on the inner and outer surfaces, respectively, and in the same number as the number of blades. In this case, the blades do not have locks and are placed in the corresponding slots with a free fit (Fig. 5). In this case, the blade load pattern changes. Now the stresses created by centrifugal forces are shifted towards compression of the blades. And the bending moment that occurs when interacting with the air flow is harmoniously distributed along the blade blade. And what is very important, not tensile, but compressive stresses arise at the edges of the blades. These are almost ideal loading conditions. At the same time, the free fit and two support points eliminate the possibility of vibrations creating critical, cyclic loads in the body of the blade.

Another significant advantage of rotors is the simplicity of the blade design. The ability to abandon the locking fastening and variable cross-section calculated mainly for reasons of fatigue strength corresponding to the nature of the load provides enormous scope for simplifying production technology. Which is sometimes even more valuable than technical advantages. The essence of a possible technology option is that in one cycle, a profile is formed from one workpiece using the strip rolling method, and then the strip is cut into individual blades that make up a complete set. At the same time, maximum identity of the blades in terms of geometry, weight, and physical and chemical properties is ensured simply and inexpensively. The economic effect can be quite significant, given that the technology for manufacturing blades is perhaps the most complex, labor-intensive, expensive and the only truly mass-produced process in the production of gas turbine engines. This is why simplifying technology in this area is critical and a priority. Including due to design solutions.

Analysis of the engine power circuit shows that the loads, mainly simple ones, are distributed between the rear support bearing, the outer rings of the turbine rotor, the transfer disk, the outer rings of the compressor rotor, the front support bearing and are closed on the housing, forming a “thin” power circuit with minimal application shoulders strength. In this case, the internal disks and the central beam are practically not loaded and serve only to position the internal rotors and blades in the plane of rotation of the corresponding disks and can be made as light as possible.

The next feature of the gas turbine engine (Fig. 4) is the cooling and lubrication scheme. In compressors, oil circulation systems are mainly used for cooling and lubrication. Its use is not excluded, but in the proposed scheme, rolling friction forces play a key role in the transmission of torque and measures to reduce them resulting from the properties of the oils will be undesirable and will require a significant increase in the compression force of the rotors. Therefore, the main negative factor that should be focused on is the removal of excess heat from the contact zone, which certainly arises where friction is present. To do this, it is proposed to use the same fuel that is used in the combustion chamber, i.e. kerosene. Kerosene has a higher heat capacity in relation to oil, higher penetrating ability and, importantly, allows you to abandon a complex, cumbersome circulation system. Fuel is dosed through channels to the rotation elements in the area of their contact with the separator. Spreads over the elements of rotation. And then it is released in the form of a vapor aerosol into the air tract. Either by inertial forces, or by creating excess pressure in the space between the housing and the rotors. Once in the compressor path, the aerosol fractions will evaporate and further cool the air, increasing the compression efficiency. Then the partially prepared fuel-air mixture enters the combustion chamber, thereby facilitating its operation and is completely consumed for its intended purpose. Afterburning of the fuel used to cool the turbine rolling elements occurs in the jet nozzle, creating, although not much, additional thrust. In the same way, the turbine blades are protected from excessive temperature effects when interacting with gases from the combustion chamber. To do this, in the inner annular rotor with a capillary gap there is a fixed ring with radial holes into which fuel is supplied. The inner annular rotor also has through radial channels (18) connecting the inner surface of the disk with the grooves for accommodating the blades. The fuel captured from the capillary gap, under the action of centrifugal forces, first enters the grooves of the blades, and then spreads over its surface, forming a protective film, which, evaporating, protects the blade body from thermal effects. The fuel used for this is also burned out in the nozzle.

The technical solutions described above, however, are not ready-made recommendations for use. They only demonstrate the openness of the presented kinematic schemes to new approaches and the possibility of developing innovative, highly efficient power plants.

Claims (2)

1. A gas turbine engine, consisting of a housing, an axial compressor and a turbine, is characterized in that between the rotors there are sets of rolling elements placed in stationary ring cages, while the sequence of rotors and rolling elements is compressed with the force necessary to transmit torque. 2. The gas turbine engine according to claim 1 is characterized in that the rotors are made in the form of rings (hollow cylinders), while the turbine and compressor blades are placed on the inner surface of the rotors.