RU2789950C1 - Front device of the combustion chamber of a gas turbine engine - Google Patents

Abstract

FIELD: gas turbine engines.

SUBSTANCE: invention relates to ground-based gas turbine engines and can be used for combustion of pre-mixed gaseous air-fuel mixtures in combustion chambers of gas turbine engines and gas turbine plants. The front device of the combustion chamber of a gas turbine engine contains a burner module with a longitudinal axis coaxial with the axis of the flame tube, a mixing channel of the burner module, fuel supply channels with fuel outlets, a flame stabilizer with petals is located at the outlet of the mixing channel, the petals are equally spaced around the circumference of the flame stabilizer and are each fixed by one side of the triangle on the outer surface of the flame stabilizer, and the ends of the side faces of the petals are placed radially in the plane of the end face of the flame stabilizer. The blades of the stabilizer are U-shaped; additionally, at the inlet to the flow part of the mixing channel, a radial-axial swirler with blades is made, inside which there are fuel supply channels with fuel supply outlets through which fuel is supplied to the mixing channel, while the angle of inclination α between the plane the symmetry of the blades of the radial-axial swirler and the corresponding radial plane passing through the axis of symmetry of the front device and the axis of the cylindrical section of the fuel supply channel to the fuel supply outlets is from 0° to 30°, the number of fuel outlets in the blades of the radial-axial swirler is in the range from 4 to 8, and the diameter ∅ of the fuel supply outlets is in the size range from 0.6 to 1.8 mm, the length L of the mixing channel is 3-7 of the height H of the mixing channel, the ratio of the radius of the inner wall of the mixing channel to the radius of its outer wall R1/R2 is within 0.4…0.65, angle β between the axis of the burner module and the line formed by the intersection of the plane passing through the central point of the upper part of the U-shaped petal equidistant from the side faces of the petal, and the plane passing through the axis of the burner module and perpendicular to the radial line passing through the central point of the upper part of the U-shaped petal is from 0° to 30°.

EFFECT: achieving a wide range of stable and pulsationless low-emission combustion in the combustion chamber in a wide range of engine operating modes and ambient temperature.

1 cl, 4 dwg

Description

The invention relates to ground-based gas turbine engines and can be used for combustion of pre-mixed gaseous air-fuel mixtures in the combustion chambers of gas turbine engines (GTE) and gas turbine plants.

A combustion chamber with a front device is known (RU No. 2527011, IPC F23R 3/36, publ. 27.08.2014), containing a burner with a mixing chamber and a device for influencing the air-fuel mixture, made in the form of a mixer with longitudinal wavy folds of a U-shaped profile, located around the circumference of the flame stabilizer in groups. EFFECT: invention allows to reduce the level of smoke and emission of harmful substances in the combustion products of fuels, eliminating overheating of the local zones of the flame tube and to implement a stable combustion process of the air-fuel mixture with suppression of vibration combustion modes.

The closest analogue in technical essence and taken as a prototype is a combustion chamber with a front device (RU No. 2456510, IPC F23R 3/36, publ. 07/20/2012) containing a burner module with a longitudinal axis coaxial with the axis of the flame tube, a mixing channel of the burner module , at the inlet to which there are fuel supply channels with outlets, at the outlet of the mixing channel there is a flame stabilizer with petals, the petals are equally spaced around the circumference of the flame stabilizer and are each fixed on one side of the triangle on the outer surface of the flame stabilizer, and the ends of the petals are placed radially in the plane of the end flame stabilizer.

The disadvantage of these devices is to ensure the stabilization of the combustion process only due to the separation of the flow from the inner wall of the channel, inside which the fuel-air mixture moves, with the formation of a zone of reverse currents inside the flame tube, which does not exclude pulsating combustion in some modes of operation of the gas turbine engine, as well as an insufficiently developed contact surface between the fresh mixture and hot combustion products in the zones of reverse currents behind the stabilization petals, which leads to a narrowing of the range of low-emission and pulsation-free operation of the combustion chamber.

The technical problem, the solution of which is provided by the implementation of the proposed technical solution and cannot be implemented using the prototype, is the limited provision of a wide range of pulsation-free operation of the combustion chamber, as well as insufficient characteristics to ensure flame stabilization during low-emission combustion.

The technical problem to be solved by the claimed invention is to provide a wide range of stable and pulsationless low-emission combustion in the combustion chamber when the engine operating mode and ambient temperature change.

The solution of the technical problem is achieved by the fact that in the front device of the combustion chamber of a gas turbine engine, containing a burner module with a longitudinal axis coaxial with the axis of the flame tube, a mixing channel of the burner module, fuel supply channels with fuel outlets, a flame stabilizer is located at the outlet of the mixing channel with petals, the petals are equally spaced around the circumference of the flame stabilizer and are each fixed by one side of the triangle on the outer surface of the flame stabilizer, and the ends of the side faces of the petals are placed radially in the plane of the end face of the flame stabilizer. According to the invention, the petals of the stabilizer are U-shaped; additionally, at the inlet to the flow part of the mixing channel, a radial-axial swirler with blades is made, inside which there are fuel supply channels with fuel supply outlets through which fuel is supplied to the mixing channel, while the angle of inclination α between the plane of symmetry of the blades of the radial-axial swirler and the corresponding radial plane passing through the axis of symmetry of the front device and the axis of the cylindrical section of the fuel supply channel to the fuel supply outlets is from 0° to 30°, the number of fuel supply outlets in the blades is radially axial swirler is in the range from 4 to 8, and the diameter ∅ of the fuel supply outlets is in the range of sizes from 0.6 to 1.8 mm, the length L of the mixing channel is 3-7 dimensions of the height H of the mixing channel, the ratio of the radius of the inner wall of the mixing channel to the radius of its outer wall R1/R2 finds within 0.4 ... 0.65, the angle β between the axis of the burner module and the line formed by the intersection of the plane passing through the central point of the upper part of the U-shaped petal equidistant from the side faces of the petal and the plane passing through the axis of the burner module and perpendicular to the radial the line passing through the center point of the upper part of the U-shaped lobe is from 0° to 30°.

Making the petals U-shaped increases the contact area between the fresh air-fuel mixture and combustion products inside the reverse current zone, which improves the performance of the combustion chamber at low engine operating conditions.

The implementation of the radial-axial swirler with blades located at the inlet to the flow part of the mixing channel provides swirling of the air-fuel mixture flow to improve flame stabilization in the combustion chamber.

Fuel supply to the mixing channel through holes located in the blades of the radial-axial swirler with an angle of inclination α between the plane of symmetry of the blades of the radial-axial swirler and the corresponding radial plane passing through the axis of the front device and the rounding axis at the inlet to the mixing channel, equal to 0° up to 30° makes it possible to provide the swirl of the air-fuel mixture flow due to the blades and the necessary diagram of the fuel concentration at the stabilizer cut. An angle α greater than 30° can lead to a stall behind the blades and worsen the quality of the mixing of fuel and air.

The selected number of fuel supply outlets in the blades of the radial-axial swirler in the range from 4 to 8 and the diameter ∅ of the fuel supply outlets in the size range from 0.6 to 1.8 mm makes it possible to provide the ratio of fuel and air pulses for formation at the outlet of the frontal devices for plotting the fuel concentration required for stable low-emission combustion in the combustion chamber. The implementation of less than 4 outlets leads to a significant distortion of concentration diagrams, more than 8 outlets - does not have a significant effect on the diagrams.

When choosing a hole diameter range of less than 0.6 mm, it increases the risk of clogging in operation, and more than 1.8 does not allow obtaining the desired fuel concentration diagrams.

The length L of the mixing channel, equal to 3-7 dimensions of the height H of the mixing channel, and the ratio of the radius of the inner wall of the mixing channel to the radius of its outer wall R1 / R2, which is in the range of 0.4 ... 0.65, provides the required degree of mixing of fuel and air in mixing channel. The length of the mixing channel is less than 3 heights of the mixing channel, leads to a decrease in the quality of the preparation of the air-fuel mixture and the failure to ensure a low level of emission, and more than 7 will lead to an increase in the dimensions of the front device. Choosing the ratio of the radius of the inner wall of the mixing channel to the radius of its outer wall R1/R2 less than 0.4 or more than 0.65 will change the concentration diagram.

The angle β between the axis of the burner module and the line formed by the intersection of the plane passing through the central point of the upper part of the U-shaped petal equidistant from the side faces of the petal and the plane passing through the axis of the burner module and perpendicular to the radial line passing through the central point of the upper part of the U-shaped petal from 0° to 30° allows you to provide the flow of the air-fuel mixture with additional spin and provide favorable conditions for stable combustion in the combustion chamber. An angle β greater than 30° will lead to a stall in the flow of the fuel-air mixture behind the stabilizer, which can provoke combustion instability.

In FIG. 1 - isometric image of the front device;

In FIG. 2 is a cross-section of the front device in a plane perpendicular to axis A of FIG. 1 and passing through the blades of the radial swirler and the fuel supply outlets;

In FIG. 3 - view of the burner module with stabilization petals;

In FIG. 4 - section of the front device along axis A.

On the cover of the front device there is a burner module 1 with a longitudinal axis A, coaxial with the axis of the flame tube, a radial-axial swirler 2 with blades 4 and a mixing channel 3. The blades 4 of the radial-axial swirler are located at the inlet to the mixing channel 3 of the burner module 1 and are installed at an angle in the α range from 0° to 30°. Inside the blades 4 of the radial-axial swirler there are fuel supply channels 5 with fuel supply outlets 6 located perpendicular to the plane of symmetry of the blade in order to provide an optimal diagram of fuel concentrations at the output 7 of the front device. The number of fuel outlets 6 varies from 4 to 8. The diameter ∅ of the fuel outlets 6 is in the size range from 0.6 mm to 1.8 mm.

The mixing channel 3 is formed by the inner wall 10 and the outer wall 11, which have a smooth profile to ensure the continuous flow of the air-fuel mixture inside it and exclude the possibility of flame stabilization inside the channel. The length L of the mixing channel is equal to 3-7 dimensions of the height H of the mixing channel.

The ratio R1/R2 of the diameter of the inner wall of the mixing channel to the diameter of its outer wall is in the range of 0.4…0.65.

At the outlet of the front device there is a flame stabilizer 8 with U-shaped hollow petals 9. The number of stabilizer petals is from 7 to 12.

The blades 9 of the stabilizer are located near the outlet of the mixing channel and are designed to stabilize the flame by simultaneously swirling the flow and stalling behind the petals. The flow is swirled by setting the stabilizer petals at an angle β between the projection of the line formed by the intersection of the plane passing through the maximum radius of the outer surface of the U-shaped petal in the center between the side edges of the petal and the axis of the burner module.

The front device of the gas turbine engine combustion chamber works as follows:

At the entrance to the front device (without position), where the blades 4 of the radial-axial swirler 2 are located, fuel is supplied through the fuel supply channels 5 to the fuel supply outlets 6, which is carried away by the air flow incident on the blades. The swirling air-fuel mixture enters downstream into the mixing channel 3 formed by the outer wall 11 and the inner wall 10. The swirling air-fuel mixture enters the outlet of the front device (without position), where the flame stabilizer 8 with U-shaped hollow petals 9. The fuel-air mixture passes through between and above the U-shaped hollow petals 9 of the flame stabilizer 8. At the same time, the petals 9 of the flame stabilizer 8 themselves impart additional swirling of the air-fuel mixture to stabilize the flame front in the volume of the flame tube of the combustion chamber. Downstream behind the blades 9 of the flame stabilizer 8, recirculation zones are formed that provide heat supply to the still unburned air-fuel mixture and stabilize the flame front.

When checking the characteristics of this invention, experimental work was successfully carried out, a positive technical result was obtained, and the device is being introduced into pilot production.

The present invention, together with the known features, makes it possible to provide a wide range of stable and pulsation-free low-emission combustion in the combustion chamber in a wide range of engine operating modes and ambient air temperature.

Claims (1)

The front device of the combustion chamber of a gas turbine engine, containing a burner module with a longitudinal axis coaxial with the axis of the flame tube, a mixing channel of the burner module, fuel supply channels with fuel outlets, a flame stabilizer with petals is located at the outlet of the mixing channel, the petals are equally spaced around the circumference of the stabilizer flame stabilizer and are each fixed by one side of the triangle on the outer surface of the flame stabilizer, and the ends of the side faces of the petals are placed radially in the plane of the end of the flame stabilizer, characterized in that the petals of the stabilizer are U-shaped, additionally, a radial-axial swirler is made at the inlet to the flow part of the mixing channel with blades, inside which there are fuel supply channels with fuel supply outlets through which fuel is supplied to the mixing channel, while the angle of inclination α between the symmetry plane of the blades of the radial-axial swirler and, respectively, the radial plane passing through the axis of symmetry of the front device and the axis of the cylindrical section of the fuel supply channel to the fuel supply outlets is from 0° to 30°, the number of fuel outlets in the blades of the radial-axial swirler is in the range from 4 to 8, and the diameter of the fuel supply outlets is in the range of sizes from 0.6 to 1.8 mm, the length L of the mixing channel is equal to 3-7 heights H of the mixing channel, the ratio of the radius of the inner wall of the mixing channel to the radius of its outer wall R1/R2 is within 0.4 ... 0.65, the angle β between the burner module axis and the line formed by the intersection of the plane passing through the central point of the upper part of the U-shaped lobe equidistant from the side faces of the lobe, and the plane passing through the burner module axis and perpendicular to the radial line, passing through the central point of the upper part of the U-shaped petal, is from 0 ° to 30 °.

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