The diffuser main combustion chamber of aircraft gas turbine engine

 

(57) Abstract:

The diffuser main combustion chamber of an aviation gas turbine engine includes a housing with spaced therein telescopic rings and diffuser channel. Diffuser channel formed near telescopic rings connected by clamps. The clamps are installed with the possibility of changing the shape of the diffuser channel depending on the operation mode, taking the form either sugraduotoje or channel with a sudden expansion. This embodiment of the diffuser increases its efficiency at various operating modes of the gas turbine engine. 3 Il.

The invention relates to the field of turbine construction, in particular to the diffusers main combustion chambers (ACS) aviation gas-turbine engines (GTE).

To reduce the speed of the air entering the flame tube OAKS and converting part of the kinetic energy in the increase of static pressure diffuser is used [1].

Known steady airflow diffuser aerodynamic type with shaped channel that provides the lowest loss of total pressure and the greatest uniformity of the velocity field [1].

Moreover, the increase in the area section consists of outer and inner housings, forming the channel of the diffuser. The opening angle of the cone from 7 to 12 degrees [1].

The main disadvantages of this cone are: a large length, which undoubtedly affects the mass characteristics of the engine, and sensitivity to change of the velocity profile at the entrance.

The analysis of the literature [1, 2, 3] shows that the most effective is the cone with the regulatory elements of the flow regime. The most widely diffusers with boundary layer suction to reduce its thickness as a means to prevent separation of the flow in diffusers with large angles. The main difference from the aerodynamic diffuser - increased angle that puts the problem of boundary layer suction, generated by the increase of the opening angle is above 12 degrees, to prevent separation of the flow and the occurrence of stagnant areas.

The primary and main shortcomings of the existing diffusers is the inability to control their modes of operation of the CCD in order to achieve maximum efficiency. Slits for air suction it would be best to place directly prior to the expected point of flow separation. However, since the position of the point from

The closest to the proposed invention is a diffuser main combustion chamber of an aviation gas turbine engine, comprising a housing located therein telescopic rings, diffuser channel [4].

The disadvantage of it is the inability of its regulation depending on the operation mode of the CCD.

Task to be solved by the present invention is directed, is to increase the efficiency of the diffuser in a wide range of engine operating conditions. The real solution to this problem is the creation of the diffuser with adjustable angle and controlled by boundary layer suction.

The problem is solved due to the fact that the diffuser main combustion chamber of an aviation gas turbine engine, comprising a housing located therein telescopic rings, diffuser channel formed near telescopic rings connected by clamps installed with the possibility of changing the shape of the diffuser channel depending on the operation mode, taking the form either sugraduotoje or channel with a sudden expansion.

This embodiment of the cone leads to the possibility of regulation Cana is the main section for exhaust air from the diffuser.

In maximum mode and when running it is necessary that the dimensions of the tear-off zones, loss of total pressure were minimal, and the pressure distribution was uniform. For this it is advisable to use a diffuser with a sudden expansion. This provides a lower sensitivity of the velocity profile at the exit of the diffuser to changes in the velocity profile of the input, which is an important advantage in cases where the velocity profile at the exit of the compressor depends on the mode of operation of the engine and operating conditions [2].

On the lower modes, it is advisable to have togravity diffuser, which ensures minimum losses associated with flow separation, and less asymmetry and irregularity of the flow [1].

In Fig. 1 shows a General view of the diffuser when it is working at full speed, longitudinal section; Fig. 2 - the same, when running on low power modes; Fig. 3 - section a-a in the rotated position.

The proposed diffuser includes a housing 1 with telescopic rings 2, 3 tabs, the axial actuator 4, the cylinder rod 5, the profiled hole 6, which can move the tabs 3.

When the engine is running and when his work on m is with sudden expansion. The gap formed between the telescopic rings are slots for exhaust air from the zone with high blood pressure. The total area of the formed slits is selected so that the exhaust air does not exceed 3-4% of the total air flow. According to [1] the air suction within the specified limits can significantly improve the efficiency of the diffuser with sudden expansion and bring him on such an important parameter as the ratio of total pressure recovery to sugradjanina the diffuser. When changing the mode of operation associated with a decrease in air flow by means of the axial actuator 4 is the extension of telescopic rings 2, while the axial actuator acts on the front ring, and through the latches 3 in axial movement involved the rest of the ring 2. Thus there is a gradual decrease in the area of flow sections of the slits and the desired reduction of the flow of the suction air. When the engine is at low modes form a cone - segregata, slits for air suction is missing.

The use of the diffuser elements of the regulation allows you to:

first, to choose the optimal shape of the channel depending on the operation modes;

secondly, the maximum mode, by increasing the distance from the sudden expansion to the reaction zone, to reduce the flow velocity, which positively affects the combustion process in the combustion chamber.

Sources of information

1. A. Lefebvre. The processes in the combustion chambers of the CCD. M.: Mir, 1986, S. 94, 115.

2. Mayorov, A. I., Yagodkin C. I. Methodology and the results of calculations of flows in channels with sudden expansion. Proceedings of CIAM, N 883, 1980.

3. M. E. Deitch, A. E. Zariankin. Fluid dynamics. M.: Energoatomizdat, 1984, S. 282, 283.

4. EP 0100135 A1, IPC 6 F 23 R 3/26, 1984, Fig. 3,3 century

The diffuser main combustion chamber of an aviation gas turbine engine, comprising a housing located therein telescopic rings, diffuser channel, characterized in that the diffuser channel formed near telescopic rings connected by clamps installed with the possibility of changing the shape of the diffuser channels depending on the operation mode, taking the form either sugraduotoje or channel with a sudden expansion.

 

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