RU2781670C1 - Burner device of a low-emission combustion chamber and a method for regulating the flow of air entering it - Google Patents

Abstract

FIELD: engine technology.

SUBSTANCE: invention relates to combustion chambers of gas turbine engines using natural gas, and can be used in marine and land-based engines. The burner device of the low-emission combustion chamber, installed at the entrance to the heat pipe, contains a housing including a fitting, a radial swirl, fuel supply channels, and a mixing chamber. At least one of the fittings has an adjustable valve block consisting of support elements, one of which is presented in the form of a sleeve with an external thread, a spring, a shut-off element made in the form of a preload rod with a plug, while holes are made in the ring of the mixing chamber with a total area, ensuring the operation of the burner device when gas is supplied only in the first: starting, fuel channel with a closed section at the entrance to the swirler.

EFFECT: increase in the reliability of regulating the flow of air entering the burner over the entire range of engine operation by regulating the flow area of the burner, using the pressure of fuel gas entering the burner cavity for this purpose.

3 cl, 7 dwg

Description

The invention relates to combustion chambers, gas turbine engines running on natural gas and can be used in marine and land engines.

The main element of a low-emission combustion chamber (CC) is a burner device (burner) in the front part of the flame tube. In modern compressor stations, in order to reduce harmful emissions of nitrogen oxide (NO _X ) and carbon monoxide (CO _X ), work is carried out on a lean fuel mixture, which can provoke the occurrence of vibration combustion, leading to exhaustion and destruction of engine elements. To ensure the operability of the ecological combustion chamber in the entire range of modes, a dual-channel fuel system is used.

Prospects for the development of low-emission CS gas turbine engines are associated with the creation of control systems that allow, in conditions of changing conditions during the operation of gas turbine engines, to influence the regulatory elements. Fuel manifolds, bypass pipes and (or) front devices of variable geometry can act as control elements (Sirotin N.N., Marchukov E.Yu., Novikov A.S. “Fundamentals of design, production and operation of aircraft gas turbine engines and power plants in the CALS technology system ”Book 1. - M .: Nauka, 2011. pp. 448, 479).

Known burner low-emission combustion chamber installed at the entrance to the flame tube ("Nikolaev gas turbine engines and installations. History of creation" SE NPKG "Zorya-Mashproekt" - Nikolaev, 2005, p. 119), and containing a housing including fittings, radial swirlers installed at the outlet of the fuel supply channels, mixing chamber. Fuel gas (hereinafter - gas) from the burner cavities is fed into the hollow blades of the swirlers and through the holes in the blades, enters the annular mixing chambers. Starting the engine and its operation in low modes is carried out by supplying gas only to the swirler of the first - starting channel. In the future, the second channel is connected. At the same time, to eliminate vibrational combustion, each mode requires its own algorithm for distributing fuel over two channels.

The disadvantage of this design is the following.

The defining parameters of the burner, such as swirler areas and gas flow rate, provide the necessary characteristics of the combustion chamber in the main (nominal) mode. In this case, the air entering the combustion zone is not regulated. Therefore, at start-up and modes below the nominal value, the amount of air entering the burner is higher than necessary, which worsens the start-up and leads to vibration combustion. In addition, here, due to the "depletion" of the fuel-air mixture at low temperatures in the combustion zone, emissions of unburned carbon monoxide and hydrocarbons increase.

The reduction of harmful emissions can be achieved by ensuring the constancy of the composition of the mixture (α=const) in the combustion zone throughout the entire range of engine operation by using elements that regulate the distribution of air in the flame tube. So, at maximum modes, a significant part of the air should be supplied to the primary zone to minimize the formation of soot and NO ₂ . When reducing engine power, to ensure low levels of CO and HC emissions, it is necessary to maintain a high temperature in the primary zone by reducing the proportion of primary air, for example, by reducing the area of the burner swirlers.

A known method for regulating the air flow (International application No. WO 94/00718, IPC F23R 3/34, 3/36, F23D 17/00, F23D 14/26, publ. 01/06/1994), which consists in changing, depending on the load of the gas turbine engine , the amount of air entering the mixing chamber of the burners. An additional supply of compressed air from the engine compressor to the burner channels is provided. This air is taken from the annular channel of the combustion chamber through a pipeline containing an adjustable valve and connected to a collector, from which this air is supplied through pipelines to each burner. Flow control is carried out by changing the passage area of the pipeline channel in the line for extracting the after-compressor air. A valve is installed in the pipeline, which changes the flow area of the pipeline. In the start mode, the valve is set to the minimum opening position and the minimum amount of air enters the burner. When the load increases, it is necessary to supply additional air to the primary zone of the flame tube, which is carried out by opening the valve and air flowing from the annular channel of the combustion chamber through the collector and pipelines to the burner channels.

The disadvantage of this method is its low efficiency, since the consumption of additional air in this case is determined not only by the dosing elements in the burner channels, but also by the pressure drop between the cavities of the annular channel of the combustion chamber and the primary zone of the flame tube. With such a scheme, as a result of air pressure losses at the valve, in the manifold and in the supply pipes, the necessary increase in air flow through the burner will probably not be ensured.

The technical result achieved in the claimed invention is the development of a device and a method for its implementation, which makes it possible to increase the reliability of regulating the flow of air entering the burner, throughout the entire range of engine operation, by regulating the burner passage area, using for this purpose the pressure of the fuel gas entering the cavity burners.

The technical result in the claimed device is achieved by the fact that in the burner device of a low-emission combustion chamber installed at the inlet to the flame tube and containing a housing including fittings, a radial swirler, fuel supply channels, a mixing chamber, in contrast to the known, at least one of the fittings an adjustable valve block is installed, consisting of support elements, one of which is presented in the form of a sleeve with an external thread, a spring, a locking element made in the form of a clamping rod with a plug, while holes with a total area are made in the mixing chamber ring, ensuring the operation of the burner device at gas supply only to the first - starting fuel channel with a closed section at the inlet to the swirler.

The technical result in the claimed method is achieved by the fact that in the method of controlling the air flow, which consists in changing, depending on the load of the gas turbine engine, the amount of air entering the mixing chamber, in contrast to the known change in the amount of air entering the mixing chamber, is carried out by closing the inlet hole into the radial swirler using a valve, while, when the main fuel gas is supplied to the second channel, the valve stem moves the ring connected to it, which opens the section at the inlet to the swirler, and when the gas supply to the second channel is stopped, the ring returns to its original position and closes this section.

In this case, the body of the burner with the body of the combustion chamber forms threaded connections through the valve sleeves in the second channel for supplying fuel gas to the burner.

The figures show:

- fig. 1 - longitudinal section of the design of the burner device;

- fig. 2 - longitudinal section of the valve;

- fig. 3 - position of the valve in the initial state (the valve is closed);

- fig. 4 - position of the valve in working condition (valve is open);

- fig. 5 - longitudinal section of the burner;

- fig. 6 - view of the burner device during assembly;

- fig. 7 - view of the valve not connected to the flange of the adjusting ring (in the case of a burner version with several valves).

In FIG. 1 shows the proposed burner device.

The composition of the remote tubular-annular CS includes: a flame tube 1, a combustion chamber housing, consisting of several (according to the number of burners) covers 2 with flanges docked with a common annular section 3. A burner 4 is fixed on each of the covers 2.

Gas is supplied to the burner through two channels. In the cavity 5 of the first - starting channel through the fitting 6, in the cavity 7 - the second channel through the fitting 8. Each cavity through the holes 9, 10 communicates with the cavities of the hollow blades of the first (starting) 11 and second 12 channels and form a swirl chamber (swirler). Holes 13 are made in each blade, through which the gas enters the annular mixing chamber 14. The blades 11 and 12 alternate for a uniform supply of gas to the mixing chamber 14.

A valve is located at the inlet to the second burner channel - see fig. 2 consists of: a sleeve 15 with two sections of external thread, differing in pitch, a spring 16, which presses the rod 17, onto which the piston 18 is screwed with grooves for the passage of gas. The position of the piston is fixed (after adjusting for the opening pressure) with a nut 19. The opposite threaded section of the rod 17 is intended for mounting the ring 20 of FIG. 3.

The method is carried out in a combustion chamber containing one or more burners with a pre-prepared air-fuel mixture in the front device.

In the initial state, at start-up and low power modes, when gas is supplied only to the first (start-up) channel of the burner, the valve is closed - see fig. 3. Ring 20 completely covers the annular channel 21 at the inlet to the burner swirler. The air from the annular channel of the COP enters the swirler through holes 22 in the ring 20, the size and number of which provide (for these modes) the necessary flow rate and uniformity of the air flow at the inlet to the swirler.

In addition, the closed valve isolates the pipeline of the main fuel manifold from the possible ingress of combustion products into it.

When switching to a higher power mode, the second (main) channel for supplying gas to the burner is connected. Accordingly, the air flow entering the burner must be increased.

Flowing out of the holes 23 (Fig. 4), the gas moves the rod 17 until it stops at the surface 24. Then, through the holes 25, 26, the gas enters the cavity of the blades 12, from where from the holes 13 into the mixing chamber 14 - see Fig. 1, 4. In this case, the ring 20, moving with the rod 17, opens the annular channel at the entrance to the swirler.

Thus, in high power modes, both gas supply channels are involved with a completely open annular channel at the inlet to the burner swirler.

With a decrease in power and turning off the gas supply to the second channel, the valve spring returns the stem with the ring to its original state, and the annular channel at the inlet to the swirler closes (while maintaining the minimum required air flow through the holes in the ring 20).

The number of docking points of the rods 17 with the ring 20 is preferably at least two to prevent distortion of the ring when moving.

A similar design of the burner device was tested in the composition of the combustion chamber, where, as a result of its use, the composition of the air-fuel mixture in the combustion zone was more uniform.

Features of the design and assembly of the burner.

Burner - see fig. 5 includes a blade swirler 27 and a body 28 with threaded bosses of the first 29 and second 30 channels, connected by welding (soldering) to form the cavities of the first 5 and second 7 gas channels. On the boss 30, the valve of FIG. 2. A ring 20 is attached to the end of the rod 17 with its flange using nuts 31.

The assembly of the burner device, consisting of the burner of FIG. 5 with cover 2 - see fig. 6:

- the boss of the first channel 29 is “attracted” by the nut 32 to the flange 33, which is attached to the cover 2 by bolts 34.

- installation of fittings 6, 8 on the boss 29 and the "external" section of the thread of the valve sleeve until it stops against the seating surface of the cover 2 - see Fig. one.

As a result, the burner on the cover is fixed by fastening the central boss 29. The design of the peripheral connection, when the burner and the cover are fastened through the “intermediate” valve sleeve, simplifies assembly, allowing for gaps C, D, D (see view B of Fig. 6), with at the same time providing the necessary reliability and tightness at the joints E and G.

The assembled burner device is mounted on the body 3 KS.

Locking (fixation from rotation along the thread) of the valve sleeve 15 is ensured by the fact that it is screwed into the boss 30 along the thread with one pitch, and the fitting 8 is screwed into the sleeve itself (and is locked from the outside) along the thread with a different pitch. Thus, the rotation of the sleeve (immediately along two thread sections with different pitches) is impossible.

The number of places for supplying the main (through valves) fuel depends on the dimensions of the burner and the gas flow rate. It is preferable to have at least three of them, evenly spaced around the circumference, because these joints are also the supports for attaching the burner to the cover.

As part of the burner, all valves, together with ring 20, must operate synchronously when opening, ensuring simultaneous stop of all contact surfaces of rods with bosses 24 (Fig. 4), for which it is possible to select the minimum local gaps at the joints "nuts 31 - ring flange 20".

A variant of the burner is possible, having several valves in the main fuel channel, but not all of them are joined to the ring 20. Then the place of gas supply, where the stem is not connected to the ring, may have the design of Fig. 7. Here, the stem 35, with the valve open, rests against the bottom of the boss 36.

Thus, this technical solution makes it possible to regulate the passage area of the burner, which in turn leads to an increase in the efficiency of regulating the air flow entering the burner device of the low-emission combustion chamber.

Claims (3)

1. A burner device of a low-emission combustion chamber installed at the inlet to the flame tube and containing a housing including fittings, a radial swirler, fuel supply channels, a mixing chamber, characterized in that at least one of the fittings has an adjustable valve block, consisting of support elements, one of which is presented in the form of a sleeve with an external thread, a spring, a locking element made in the form of a clamping rod with a plug, while in the ring of the mixing chamber there are holes with a total area that ensures the operation of the burner when gas is supplied only to the first - starting - fuel channel with a closed section at the inlet to the swirler. 2. A method for regulating the flow of air entering the burner, which consists in changing, depending on the load of the gas turbine engine, the amount of air entering the mixing chamber, characterized in that the change in the amount of air entering the mixing chamber is carried out by closing the inlet hole into the radial swirler with the help of a valve, while when the main fuel gas is supplied to the second channel, the valve stem moves the ring connected to it, which opens the section at the inlet to the swirler, and when the gas supply to the second channel is stopped, the ring returns to its original position and closes this section. 3. A burner device for a low-emission combustion chamber according to claim 1, characterized in that the burner body with the combustion chamber body forms threaded connections through the valve sleeves in the second channel for supplying fuel gas to the burner.

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