RU2334892C1 - Turboprop gas turbine engine - Google Patents

Abstract

FIELD: engines and pumps.

SUBSTANCE: turboprop gas turbine engine incorporates a propeller, an air intake, a compressor, a combustion chamber, a turbine and a jet nozzle. The engine represents a two-shaft design. Behind the turbine, the Stirling engine is arranged coupled by its inner shaft, via a reduction gear or a multiplexer, with the propeller. Air branch pipes are connected to the said Striling engine, their ends passing to atmosphere and being connected to either air intake or the output of the compressor first stages.

EFFECT: higher power plant efficiency and reliability.

4 cl, 4 dwg

Description

The invention relates to engine building, including aircraft and stationary engines, in particular to turboprop engines - theater.

Known aircraft combined engine according to the application of the Russian Federation for invention No. 2002115896, containing a gas turbine engine and a rocket engine.

The disadvantage is the very high fuel consumption consumed by the rocket engine.

Known aviation gas turbine engine according to the patent of Russian Federation No. 2211935, a prototype containing a compressor, a combustion chamber, a turbine and a jet nozzle.

The disadvantage is low efficiency and, as a consequence, the high specific fuel consumption inherent in turbojet engines compared to piston engines.

The disadvantages of this engine: the very small power of electric machines, due to the fact that they are placed on a small diameter and have one step. In addition, there are problems with cooling the stator windings located inside the engine. This design is applicable for using an electric machine as a starter or as an auxiliary electric generator to power the units of a gas turbine engine and aircraft.

Objectives of the invention: improving the efficiency and reliability of the engine.

Objectives of the invention: improving efficiency and engine reliability. A turboprop gas turbine engine containing a screw, an air intake, a compressor, a combustion chamber, a turbine and a jet nozzle, characterized in that the engine is designed according to a two-shaft scheme, a Stirling engine is installed behind the turbine, connected by an internal shaft through a gearbox or a multiplier with a screw. Air tubes are connected to the Stirling engine. The ends of the nozzles go into the atmosphere. The ends of the nozzles are connected to the air intake or to the outlet of the first stages of the compressor.

The proposed technical solution has novelty, inventive step and industrial applicability, as evidenced by patent research. To implement the invention, it is sufficient to use the known components and parts previously developed and implemented in the design of gas turbine engines and in mechanical engineering.

The invention is illustrated in figure 1 ... 4, where:

figure 1 shows a diagram of the engine,

figure 2 shows the cooling circuit of the Stirling engine,

figure 3 shows a diagram of a Stirling engine,

figure 4 shows a view aa of the Stirling engine.

The proposed solution (Fig. 1) comprises a screw 1, a shaft of a screw 2, a reducer 3 (or a multiplier), a gas generator 4, which in turn contains an air intake 5, a compressor 6, a combustion chamber 7, and a turbine 8. The turbine 8 may contain one or more steps. Further, the engine design is described by the example of a single-stage turbine. The turbine 8 comprises a nozzle apparatus 9 and an impeller 10, then a jet nozzle 11.

The turboprop gas turbine engine contains a fuel supply system with a low pressure fuel pipe 12 connected to the inlet of the fuel pump 13 having a drive 14, a high pressure fuel pipe 15, the input of which is connected to the fuel pump 13, and the output is connected to the annular manifold 16, the annular manifold 16 is connected to nozzles 17 of the combustion chamber 7.

Compressor 6 comprises a compressor rotor 18 with an external shaft 19. An impeller of a turbine 10 is mounted on the external shaft 19.

The inner shaft 20 extends inside the outer shaft 19, is mounted on bearings 21 and is connected on one side to the gearbox 3, and on the other to the Stirling engine 22. An air pipe 23 or several air pipes connected to the Stirling engine, the other end of which is released into the atmosphere, and exhaust pipes 24 that extend into the jet “D” inside the jet nozzle 11.

A distinctive feature of the power plant is the presence of the Stirling engine 22 behind the turbine 8, specifically behind the impeller of the turbine 10.

The Stirling engine 22 consists of two parts: a group of working cylinders 25 and a group of displacement cylinders 26, which are connected by pipelines 27. It is preferable to insulate the group of displacement cylinders 26 from the gas turbine engine.

In one embodiment, it is possible to connect the air pipe 23 (air pipes) to the air intake 5 or to the first stages of the compressor 6 through one or more pipelines 28 (figure 2).

Figures 3 and 4 show a diagram of one embodiment of the Stirling engine 22, which contains a group of working cylinders 25 having fins 29 with a working piston 30 installed inside each of them in the cavity “B”, which is connected to the internal shaft of the engine 20 by a connecting rod 31 .

Also, the Stirling engine 22 contains a group of displacement cylinders 26 with a displacement piston 32 installed inside each of them in the cavity “B”. Each expansion cylinder 26 is equipped externally with a casing 33 forming a cavity “G” for cooling the expansion cylinder 26. The displacement piston 32 is connected by a connecting rod 34 with the internal shaft of the engine 20. A pipe 27 connects the cavity "B" and "C" for the flow of the working fluid from the working cylinder 25 into the displacement cylinder 26. Air tubes 23 are connected to the cavity "G", and the exhaust pipes s 24 connect the cavity "G" with the internal cavity "D" of the jet nozzle 11 (figure 1).

During the operation of the gas turbine engine, it is started by the starter (the starter in Figs. 1 ... 4 is not shown). Then, the drive of the fuel pump 14 is turned on, and the fuel pump 13 delivers fuel to the combustion chamber 7, where it is ignited by an electric igniter (not shown in FIG. 1). As a result, the combustion products pass through the impeller of the turbine 10 and untwist it and the external shaft 20, as well as the compressor rotor 18. After 5 ... 7 min, the heat of the exhaust gases warms the working cylinders 25 of the Stirling engine 22. The Stirling engine 22 is driven and through inner shaft 20 and gearbox 3 loosens screw 1. As a result, the engine is started and ready for operation. Control of the engine by modes and turning it off does not differ from traditional TVDs.

The application of the invention allowed:

1. To increase the efficiency of a gas turbine engine due to a more rational layout of the engine, the presence of a screw giving additional traction, the absence of a rigid kinematic connection between the compressor and the turbine. This made it possible to design optimal compressor and turbine, for example, at different operating speeds and optimally coordinate their joint work.

2. Improve the reliability of the power plant by reducing the number of turbine stages to one stage and distributing most of the load on the Stirling engine.

3. To create favorable conditions for the operation of the propeller and Stirling engine by coordinating their optimal calculated angular rotational speeds through the use of a gearbox or multiplier. In addition, the use of a two-shaft engine design will allow you to mechanically decouple the impeller and rotor of the turbine and compressor on the one hand from the screw and Stirling engine, whose operation at start-up and during transient conditions varies significantly, for example, in terms of shaft speed and acceleration.

4. To ensure optimal engine operation in transient conditions, due to the fact that turboprop engines create part of the propeller thrust, and part due to the jet nozzle. Despite the poor throttle response of the Stirling engine with a sharp change in fuel consumption through the combustion chamber, the total thrust of the engine will change almost instantly due to the reactive component. After 5 ... 7 min, the powers developed by the propeller and the gas generator will be redistributed, for example, when forcing, the main thrust load will be borne by the propeller, which has good efficiency at subsonic speeds, as a result, the efficiency of the engine at cruising flight mode will increase significantly.

5. The fuel consumption during the operation of the aircraft will significantly decrease, this is important in connection with the exhaustion of hydrocarbon fuel resources, its cost increase and the lack of an alternative to this type of fuel. The use of hydrogen, which has a cost hundreds of times greater than kerosene, is unpromising in the next 100 years, and the use of liquefied natural gas due to its poor energy characteristics and the difficulty in operating cryogenic equipment is very limited.

6. To facilitate the working conditions of the screw due to its non-rigid connection with the compressor shaft and the possibility of their mutual slippage and mismatch of the rotor speed of the compressor and screw.

7. Facilitate starting and stopping the engine through the use of a two-shaft scheme.

8. Reduce the weight and dimensions of the engine.

9. To reduce the cost of the engine due to the rejection of expensive materials used in the manufacture of the turbine.

Claims (4)

1. A turboprop gas turbine engine containing a screw, an air intake, a compressor, a combustion chamber, a turbine and a jet nozzle, characterized in that the engine is designed according to a two-shaft scheme, a Stirling engine is installed behind the turbine, connected by an internal shaft through a gearbox or a multiplier with a screw. 2. Turboprop gas turbine engine according to claim 1, characterized in that the air pipes are connected to the Stirling engine. 3. The turboprop gas turbine engine according to claim 2, characterized in that the ends of the nozzles exit into the atmosphere. 4. The turboprop gas turbine engine according to claim 2, characterized in that the ends of the nozzles are connected to the air intake or to the exit of the first stages of the compressor.

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