RU2595287C1 - Gas turbine engine combustion chamber with controlled distribution of air - Google Patents

Abstract

FIELD: engines and pumps.

SUBSTANCE: gas turbine engine combustion chamber with controlled distribution of air comprises housing accommodating fire tube with nozzles and swirler with inlet conical section consisting of two telescopically interconnected front and rear parts. Each part of flame tube is rigidly secured to housing, front part is at inlet, and rear part is at outlet. Secondary air supply holes are made on output edge of front part of flame tube. Rear part of flame tube is connected by means of tie rod with adjusting plate located in conical section, made converging to input of swirler. Adjusting plate is made in form of a circle, which plane is perpendicular to axis of cone section to make variable by area annular gap at movement along conical section. During movement of plate along conical section converging to input of vortex changes area of annular gap and thus, air flow to flame tube is controlled.

EFFECT: invention allows to reduce emissions of NO_x in wide range of modes of operation of gas turbine engine.

1 cl, 6 dwg

Description

The invention relates to gas turbine engines (GTE), and specifically to combustion chambers with a controlled distribution of air, and allows to reduce NO _x emissions in a wide range of operating modes of a gas turbine engine.

The well-known "Combustion chamber of a gas turbine engine with adjustable air distribution" (RF patent No. 2163991, IPC F23R 3/26, published: 03/10/2001), containing a heat pipe with windows in its wall overlapping by a movable element located at the location of the windows. The movable element is made in the form of a flexible tape covering the flame tube having at least one cut. Tape cuts are connected to the lever system with a drive, and it provides radial movement of the tape. This embodiment of the combustion chamber increases the reliability of its operation and provides the required distribution of air along the length of the combustion chamber.

In connection with the stricter requirements for the emissions of GTE harmful substances (carbon monoxide — CO, unburned hydrocarbons — C _n H _m , nitrogen oxides — NO _x ), there is a need to develop combustion chambers with low emissions of these substances. Among other solutions (steam or water supply to the combustion chamber), redistribution of air flow along the length of the combustion chamber is used to ensure optimal combustion conditions in the entire working range of gas turbine engine operating modes. At the same time, to prevent the formation of CO and C _n H _m at low conditions and to ensure normal start-up of the combustion chamber, the air flow to the primary zone is reduced, and at high conditions to prevent the formation of NO _x , the air flow to the primary zone is increased.

Known devices of combustion chambers in which air is distributed along its length, for example, US patent No. 4534166, in which an adjustable swirl is used in the front device of the combustion chamber; U.S. Pat. US patent No. 4594848, in which rings are moved along the axis of the combustion chamber to block the windows in the flame tube.

A known combustion chamber of a gas turbine engine with adjustable air distribution, containing a flame tube with overlapping windows in its wall, and a movable element located at the location of the windows, connected via a lever system with a drive (EP 0100135 A1, IPC ⁶ F23R 3/26, 1984). A disadvantage of the known devices is their low reliability, since when the walls of the flame tube are heated, the rings and belts moving along it do not provide tightness (when closed), which does not regulate the optimal distribution of air along the length of the flame pipe, or (with sufficient tightness, i.e., with small gaps), failures in the movements of the regulating elements may occur due to warpage of the flame tube, especially when it is heated unevenly, and from temperature expansion of the flame tube and proxy elements.

Known combustion chamber of an adaptive type (application No. 94022641, IPC F23R 3/26, publ. 06/20/1996), comprising a housing with annular inner and outer shells and a heat pipe placed therein with nozzles, a swirl and openings for supplying secondary air, a heat pipe made movable, consists of front and rear parts, telescopically connected to each other, in the front part of the flame tube, a flow separator is rigidly fixed, there are guides on the outer and inner walls of the front part that allow axial movement The direction of the front of the flame tube, by adjusting the optimal ratio of air flow, and adjust the flow area of the secondary air through the holes overlap profiling openings front and rear parts of the combustion chamber.

A disadvantage of the known combustion chamber is the low reliability of the chamber associated with the need to have an axial drive driven by a separate mechanism and the difficulty of controlling the movement of the front part of the flame tube by this mechanism, requiring communication with the automatic engine control system.

The technical result to which the invention is directed is to increase the reliability of the device controlling the air flow and simplify its design, as well as to reduce emissions of harmful substances.

The technical result is achieved in that in a combustion chamber containing a housing and a heat pipe placed therein with nozzles and a swirl with an inlet conical section, consisting of two front and rear parts telescopically connected to each other, it is new that each of the parts of the heat pipe is rigid fixed to the housing - the front part is at the inlet, the rear part is at the outlet, the secondary air supply openings are made at the output edge of the front part of the flame tube, the rear part of the flame tube is equipped with a rod connected to a control plate located in a conical section made tapering to the entrance to the swirl.

The control plate is made in the form of a circle, the plane of which is perpendicular to the axis of the conical section, with the possibility of forming a variable annular gap in area when moving along the conical section.

Thus, the new features are:

1. Two telescopic movable front and rear parts of the flame tube, which can move with thermal expansion in the opposite direction to each other.

2. The movable control plate is mounted in a conical pipe, tapering towards the entrance to the swirl, and is connected to the drive from the back of the flame tube.

3. Secondary air holes located on the edge of the front of the flame tube, overlapped by the rear wall, which is movable during thermal expansion.

In FIG. 1 shows a section through a combustion chamber at low conditions.

In FIG. 2 is a view A of FIG. one.

In FIG. 3 is a view B of FIG. one.

In FIG. 4 shows a section through a combustion chamber under high conditions.

In FIG. 5 is a view B of FIG. four.

In FIG. 6 is a view D of FIG. four.

The combustion chamber contains a heat pipe, consisting of two front 1 and rear 2 parts telescopically connected to each other, each of which is rigidly fixed to the camera body using clamps: the front part 1 of the heat pipe is at the entrance, the rear part 2 is at the exit. In addition to the front part 1, the outlet has secondary air inlet openings. The back part 2 of the flame tube contains a rod connected to the lever 3 and the regulating plate 4 located in the conical section 5, tapering to the entrance to the swirl 6. The regulating plate 4 is made in the form of a circle, the plane of which is perpendicular to the axis of the conical section 5. When moving the plate 4 along the conical section 5, tapering to the inlet of the swirler, the annular gap area h1 changes at low conditions and h2 at high conditions, thus, the air flow into the flame tube is regulated.

The air flow into the primary zone of the flame tube is determined by the location of the plate 4 in the conical section 5, which defines the flow area of the air flow for this mode. In the starting mode of a gas turbine engine or at low modes, the air flow into the primary zone of the flame tube is reduced, since the stable combustion of the air-fuel mixture in the primary zone and a small amount of unburned C _n H _m provides a small formation of CO.

At high operating conditions of the combustion chamber, there is a strong (up to 1000 K) heating of the walls of both parts of the flame tube, which causes mutual displacement (from 1 to 5 mm) of the rear part 2 towards the entrance and the front part 1 towards the exit. As a result of thermal expansion of the rear part 2, a rod attached to it by means of a lever 3 shifts the control plate 4 from the inlet of the swirl 6 to the entrance to the conical section 5 and opens the air supply area through it to the primary zone. At the same time, when both parts of the flame tube expand, the holes in the front part 1 are blocked by the outer wall of its rear part 2 and the air flow is redistributed to the front device and enters the combustion zone. With an increase in the load of the combustion chamber, respectively, and the temperature of the walls, the overlap of the holes increases, and the flow area of the swirl 6 also increases. As a result of increasing air flow into the combustion zone, which allows to maintain in combustion zone depleted mixture compositions at which NO _x emissions are reduced in a wide range of the combustion chamber.

The present invention allows to reduce emissions of NO _x , as a result of increased air flow through the swirler 6 in the combustion zone.

It is known that NO _x emissions strongly depend on temperature in the combustion zone, in accordance with the dependence NO _x ~ exp (0.009T) (Lefebvre A. Processes in the combustion chambers of a gas turbine engine. M; Mir, 1066, p. 127, 167, 175, 495)

The greatest emission of NO _x occurs at T> 1800 K, therefore, with an increase in the load of the combustion chamber, it is necessary to maintain lean compositions in the combustion zone with an air excess coefficient α> 1.2, at which the temperature in the combustion zone does not exceed 1800 K in a wide range of operating modes .

With an increase in fuel supply, the temperature of the gas stream in the combustion chamber increases, respectively, the temperature of the walls of both parts of the heat pipe and their mutual expansion increase, which leads to the overlapping of the secondary air holes located in front of the heat pipe with the walls of its rear part, and at the same time increase the annular gap as a result of displacement of the plate from the conical inlet of the swirler. The specified combined action provides an increase in air flow through the swirl 6 in the combustion zone and its depletion. With the depletion of the combustion zone, NO _x emissions are significantly reduced.

Thus, the present invention allows to reduce emissions of harmful substances, to increase the reliability of the combustion chamber by simplifying the design due to auto-regulation of air flow in the primary zone with thermal expansion of the walls of the flame tube.

Claims (2)

1. The combustion chamber of a gas turbine engine with adjustable air distribution, comprising a housing, a heat pipe placed therein with nozzles and a swirl with an inlet conical section, consisting of two front and rear parts telescopically connected to each other, characterized in that each of the parts of the heat pipe is rigidly fixed to the body - the front part is at the inlet, the rear part is at the outlet, the secondary air inlet holes are made at the outlet edge of the front part of the flame tube, and the rear part of the flame pipe is connected on by means of a thrust with a control plate located in a conical section made tapering to the entrance to the swirl. 2. The combustion chamber according to claim 1, characterized in that the control plate is made in the form of a circle, the plane of which is perpendicular to the axis of the conical section, with the possibility of forming a variable annular gap in area when moving along the conical section.

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