A dual fuel nozzle for a gas turbine and a combustion chamber thereof

Abstract

The present application belongs to the technical field of gas turbine fuel nozzle, and particularly relates to a dual-fuel nozzle of a gas turbine and its combustion chamber, comprising a concentric fuel pipe, a liquid fuel nozzle and a mixing cap cover; the liquid fuel nozzle is connected to the front end of the concentric fuel pipe; the mixing cap cover is installed at the front end of the concentric fuel pipe, and after the liquid fuel is injected into the mixing cavity, it collides and splashes with the mixing cap cover to complete the primary atomization, and then completes the secondary pneumatic atomization under the action of the gas fuel or the atomizing air to form a uniform gas-liquid mixture, which is finally injected into the combustion chamber through the fuel injection holes on the cap cover. The nozzle of the present scheme has a liquid fuel mode, a gas fuel mode and a gas-liquid dual fuel mode, and can realize free switching. When the liquid fuel mode is adopted, the liquid fuel completes collision atomization and pneumatic atomization in the mixing cap cover, and is mixed with the gas fuel or the air to realize efficient atomization and mixing of the liquid fuel, optimize the fuel distribution and improve the performance of the combustion chamber.

Description

Technical Field

[0001] This invention belongs to the field of gas turbine fuel nozzle technology, specifically relating to a dual-fuel nozzle for a gas turbine and its combustion chamber. Background Technology

[0002] Gas turbine engines need to meet different applications and usage scenarios, and the fuels used vary depending on the scenario. Based on fuel form, they can be divided into liquid fuels and gaseous fuels. Liquid fuel gas turbine engines have advantages such as good combustion stability, high combustion efficiency, and easy ignition, but meeting national emission requirements is relatively difficult. Their main advantage is that liquid fuels are easy to store and transport, making them convenient to use. Gas-fueled gas turbine engines that burn natural gas have advantages such as good combustion performance, achieving clean combustion, and meeting emission regulations when designed for low emissions. Their disadvantage is the large amount of gaseous fuel required, necessitating specialized pipelines and fuel processing equipment. In industrial production, gas turbines need to operate continuously for long periods, often using a single fuel as the primary fuel. For example, offshore platforms use associated gas as their primary fuel. To avoid problems caused by fluctuations in the main fuel supply, a dual-fuel mode is generally adopted, using another fuel as a backup. The conventional approach is to use liquid fuel as a backup because liquid fuels are easy to store and transport, and the related fuel equipment is relatively simple. In summary, designing a dual-fuel nozzle capable of arbitrarily switching between liquid fuel mode, gas fuel mode, and gas-liquid dual fuel mode has become one of the problems that must be solved. Summary of the Invention

[0003] This solution addresses the aforementioned technical problems and provides a dual-fuel nozzle for a gas turbine and its combustion chamber, enabling operation in liquid fuel mode, gas fuel mode, and gas-liquid dual fuel mode, with the ability to freely switch between different operating modes.

[0004] The technical solution adopted in this invention is as follows:

[0005] A dual-fuel nozzle for a gas turbine and its combustion chamber includes a concentric fuel pipe, a liquid fuel nozzle, and a mixing cap. The concentric fuel pipe has a liquid fuel passage and a gas fuel passage. The liquid fuel nozzle is connected to the front end of the concentric fuel pipe and has a Venturi jet orifice and a gas fuel swirl orifice. The Venturi jet orifice communicates with the liquid fuel passage, and the gas fuel swirl orifice communicates with the gas fuel passage. The mixing cap is installed at the front end of the concentric fuel pipe, and a mixing chamber is formed between the mixing cap and the liquid fuel nozzle. The liquid fuel can be atomized aerodynamically and atomized by impact in the mixing chamber and mixed with gas fuel or air. An external mixing fuel injection orifice is provided on the mixing cap, through which the fuel in the mixing chamber can be ejected outward.

[0006] As an alternative or supplement to the above structure: a conical collider is provided on the inner wall of the hybrid cap, with the tip of the conical collider facing the Venturi jet orifice.

[0007] As an alternative or supplement to the above structure: the root of the cone-shaped collider has a stepped surface perpendicular to the axis of the cone-shaped collider.

[0008] As an alternative or supplement to the above structure: the concentric fuel tube includes a liquid fuel tube and a gas fuel tube, the gas fuel tube being coaxially sleeved outside the liquid fuel tube; the liquid fuel channel is located inside the liquid fuel tube, and the gas fuel channel is located between the liquid fuel tube and the gas fuel tube.

[0009] As an alternative or supplement to the above structure: the liquid fuel nozzle is sealed to the front end of both the liquid fuel pipe and the gas fuel pipe, the venturi jet orifice is located at the center of the liquid fuel nozzle, and the gas fuel swirl orifice is located at the edge of the liquid fuel nozzle.

[0010] As an alternative or supplement to the above structure: the Venturi jet orifice includes a Venturi contraction orifice section, a Venturi throat orifice section, and a Venturi expansion orifice section; the diameter of the Venturi contraction orifice section is smaller at the front and larger at the back, the diameter of the Venturi expansion orifice section is larger at the front and smaller at the back, and the diameter of the Venturi throat orifice section is the same at the front and back; the small end of the Venturi contraction orifice section and the small end of the Venturi expansion orifice section face each other, and the Venturi throat orifice section is located between the small end of the Venturi contraction orifice section and the small end of the Venturi expansion orifice section.

[0011] As an alternative or supplement to the above structure: the outlets of the Venturi jet orifice and the gas fuel swirl orifice are located on the same plane.

[0012] As an alternative or supplement to the above structure: the front end of the gas fuel pipe is externally threaded with a nut, and the front end of the nut is fixedly connected to the mixing cap; the mixing cap is hemispherical.

[0013] As an alternative or supplement to the above structure: the inlet of the liquid fuel pipe is located at its rear end and extends outside the rear end of the liquid fuel pipe; the inlet of the gas fuel pipe is located on the rear side wall and is perpendicular to the axis of the gas fuel pipe.

[0014] As an alternative or supplement to the above structure: the external injection hole of the mixed fuel is a swirling hole; the external injection hole of the mixed fuel includes a concentric outer ring swirling channel and an inner ring swirling channel, the rotation direction of the outer ring swirling channel and the inner ring swirling channel is the same or opposite, and the rotation direction of the gaseous fuel swirling hole is the same or opposite to the rotation direction of the outer ring swirling channel.

[0015] A gas turbine has a combustion chamber inside the gas turbine, and a dual-fuel nozzle of the gas turbine combustion chamber is installed on the outer wall of the combustion chamber, with the ignition end of the dual-fuel nozzle extending into the combustion chamber.

[0016] The beneficial effects of this invention are as follows:

[0017] 1. The dual-fuel nozzle of this solution can input gaseous fuel, liquid fuel, air and other media, thereby achieving liquid fuel mode, gaseous fuel mode and gas-liquid dual fuel mode, and can freely switch between the three modes; gaseous fuel can be natural gas, coke oven gas, oilfield semi-gas, multi-component syngas and other gaseous fuels, and liquid fuel can be diesel, kerosene, gasoline and other liquid fuels, and the fuel type can be selected independently according to actual needs;

[0018] 2. In this solution, the fuel can be atomized by collision and aerodynamic atomization within the mixing cap and mixed with gaseous fuel or air, so that the liquid fuel can form uniform and fine droplets, thereby achieving the effect of efficient atomization and mixing of liquid fuel, optimizing fuel distribution, and improving combustion chamber performance. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this scheme or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below.

[0020] Figure 1 This is a cross-sectional structural diagram of the dual-fuel nozzle in this design;

[0021] Figure 2 This is an enlarged view of the front end of the dual-fuel nozzle in this design.

[0022] Figure 3 This is a schematic diagram of the liquid fuel nozzle in this design.

[0023] Figure 4 This is a front view of the hybrid cap in this design.

[0024] In the diagram: 1-Liquid fuel pipe; 2-Gaseous fuel pipe; 3-Liquid fuel nozzle; 4-Mixing cap; 5-Liquid fuel passage; 6-Gaseous fuel passage; 7-Mixing chamber; 8-Gaseous fuel swirl orifice; 9-Nut; 10-Outer annular swirl channel; 11-Inner annular swirl channel; 12-Conical collider; 13-Mixed fuel external injection orifice; 14-Venturi jet orifice; 15-Venturi contraction orifice section; 16-Venturi throat orifice section; 17-Venturi expansion orifice section. Detailed Implementation

[0025] The technical solutions in this embodiment will be clearly and completely described below with reference to the accompanying drawings. The described embodiments are only a part of the embodiments, not all of them. All other embodiments obtained by those skilled in the art based on the embodiments in this solution without creative effort are within the protection scope of this solution.

[0026] Example 1

[0027] like Figures 1 to 4 As shown, this embodiment designs a dual-fuel nozzle for a gas turbine combustion chamber, including components such as a concentric fuel pipe, a liquid fuel nozzle 3, a mixing cap 4, and a nut 9.

[0028] The concentric fuel tube includes a liquid fuel tube 1 and a gas fuel tube 2, with the gas fuel tube 2 coaxially sleeved outside the liquid fuel tube 1. The inlet of the liquid fuel tube 1 is located at its rear end and extends beyond the rear end of the liquid fuel tube 1; the inlet of the gas fuel tube 2 is located on its rear side wall and is perpendicular to the axis of the gas fuel tube 2.

[0029] The concentric fuel pipe has a liquid fuel channel 5 and a gaseous fuel channel 6; the liquid fuel channel 5 is located inside the liquid fuel pipe 1, and the gaseous fuel channel 6 is located between the liquid fuel pipe 1 and the gaseous fuel pipe 2. The liquid fuel channel 5 is used to deliver liquid fuel, such as diesel or gasoline, while the gaseous fuel pipe 2 is used to deliver gaseous fuel or air, such as clean fuels like pure hydrogen, mixed hydrogen, or multi-component gases.

[0030] The fuel mix within the concentric fuel lines can be customized to select the appropriate fuel type based on actual needs, allowing for seamless switching between three modes: liquid fuel mode, gas fuel mode, and gas-liquid dual fuel mode. In liquid fuel mode, liquid fuel is supplied to liquid fuel line 1, and air is supplied to gas fuel line 2. In gas fuel mode, liquid fuel supply to liquid fuel line 1 is stopped, and gas fuel is supplied to gas fuel line 2. In gas-liquid dual fuel mode, liquid fuel is supplied to liquid fuel line 1, and gas fuel is supplied to gas fuel line 2.

[0031] The liquid fuel nozzle 3 is connected to the front end of the concentric fuel tube, and the liquid fuel nozzle 3 is sealed to both the front end of the liquid fuel tube 1 and the front end of the gas fuel tube 2. The liquid fuel nozzle 3 has a Venturi jet orifice 14 and a gas fuel swirl orifice 8. The Venturi jet orifice 14 is located at the center of the liquid fuel nozzle 3, and the gas fuel swirl orifice 8 is located at the edge of the liquid fuel nozzle 3. The Venturi jet orifice 14 communicates with the liquid fuel channel 5, and the gas fuel swirl orifice 8 communicates with the gas fuel channel 6.

[0032] The Venturi jet orifice 14 includes a Venturi contraction section 15, a Venturi throat section 16, and a Venturi expansion section 17. The diameter of the Venturi contraction section 15 is smaller at the front and larger at the back, the diameter of the Venturi expansion section 17 is larger at the front and smaller at the back, and the diameter of the Venturi throat section 16 is the same at both ends. The small end of the Venturi contraction section 15 and the small end of the Venturi expansion section 17 face each other, and the Venturi throat section 16 is located between the small ends of the Venturi contraction section 15 and the Venturi expansion section 17. After passing through the Venturi jet orifice 14, the liquid fuel is ejected at high speed under the influence of the Venturi effect, providing kinetic energy for the collision atomization and aerodynamic atomization of the liquid fuel in the mixing chamber 7, thereby improving the atomization effect of the liquid fuel.

[0033] The outlets of the Venturi jet orifice 14 and the gas fuel swirl orifice 8 are located on the same plane, thereby avoiding the formation of dead angles between them that would affect the collision and mixing effect of the liquid flow and the gas flow.

[0034] A mixing cap 4 is installed at the front end of a concentric fuel pipe, and a mixing chamber 7 is formed between the mixing cap 4 and the liquid fuel nozzle 3. The liquid fuel can be atomized pneumatically and atomized by impact in the mixing chamber 7 and mixed with gaseous fuel or air; wherein the airflow involved in the atomization is air or gaseous fuel. A conical impactor 12 is provided on the inner wall of the mixing cap 4. The tip of the conical impactor 12 is directly opposite the Venturi expansion orifice section 17 of the Venturi jet orifice 14. The liquid fuel accelerated from the Venturi jet orifice 14 can directly collide with the conical impactor 12, thereby achieving the effect of impact atomization.

[0035] The cone-shaped collider 12 has a stepped surface at its root that is perpendicular to the axis of the cone-shaped collider 12. Since the stepped surface is perpendicular to the direction of liquid fuel ejection, when the liquid fuel that collides with the cone-shaped collider 12 collides with the stepped surface again under the action of inertia and bounces back, the bounced liquid fuel can collide with the subsequent liquid fuel again, thereby improving the collision atomization effect.

[0036] A mixed fuel external injection port 13 is provided on the mixing cap 4, through which fuel in the mixing chamber can be ejected outward. The mixed fuel external injection port 13 is a swirling orifice; the mixed fuel external injection port 13 includes a concentric outer ring swirling channel 10 and an inner ring swirling channel 11, the outer ring swirling channel 10 and the inner ring swirling channel 11 rotate in the same or opposite directions, and the rotation direction of the gaseous fuel swirling orifice 8 is the same or opposite to the rotation direction of the outer ring swirling channel 10.

[0037] The front end of the gas fuel pipe 2 is externally threaded with a nut 9. The front end of the nut 9 is fixedly connected to the mixing cap 4 by brazing, threaded connection or other means. The mixing cap 4 is hemispherical. Since the distance between the conical collider 12 and the Venturi jet orifice 14 will affect the collision atomization effect, and the structure of the mixing cap 4 is relatively complex, the design of the nut 9 can effectively improve the fault tolerance. That is, by replacing the nut 9 with different lengths, the sealing between the gas fuel pipe 2 and the nut 9 can be guaranteed, while the distance between the conical collider 12 and the Venturi jet orifice 14 can be changed.

[0038] In this design, the dual-fuel nozzle operates in either liquid fuel mode or gas-liquid dual-fuel mode as follows: After the liquid fuel is ejected from the Venturi jet orifice 14, it flows forward at high speed in the form of fine droplets, then impacts the conical impactor 12. Upon impact, the liquid fuel is torn and broken apart, forming even finer droplets within the mixing chamber 7, which then disperse in all directions, completing the first atomization. Even under low-pressure conditions, this design can achieve ultra-fine atomized droplets, a performance difficult to achieve with traditional nozzles that rely solely on pneumatic or mixed atomization. Atomizing nozzles with an internal solid-state collision mechanism offer even better atomization efficiency.

[0039] Meanwhile, the high-pressure gas introduced into the gas fuel channel 6 generates a swirling flow after passing through the gas fuel swirling hole 8, and then is ejected. The droplets that have completed one atomization will mix with the high-pressure gas in the swirling state in the mixing chamber 7. Affected by the strong turbulence and shearing effect of the gas generated by the swirling flow, the liquid fuel droplets that have completed one atomization will accelerate to break up and quickly undergo secondary atomization to produce more uniform and fine liquid fuel droplets.

[0040] The dual-fuel nozzles in this design can switch between fuel modes arbitrarily according to different sites and operating conditions. In either mode, high fuel atomization and mixing are achieved, optimizing fuel distribution and improving the combustion chamber performance of the gas turbine. The fuel modes in this design mainly refer to liquid fuel mode, gas fuel mode, and gas-liquid dual-fuel mode.

[0041] Specifically:

[0042] 1. Liquid fuel mode: High-pressure air is introduced into the gas fuel channel 6. Fuel flows out of the venturi tube at high speed and impacts the conical collision body 12 to form fine droplets. The high-pressure air flows into the mixing chamber 7 through the swirling hole to atomize the droplets. The droplets are formed into finer and more uniform droplets by the swirling action of the high-pressure air.

[0043] 2. Gas fuel mode: The liquid fuel channel 5 is closed, and the gas fuel generates strong vortices in different directions through the gas fuel swirl hole 8, and they collide and atomize with each other.

[0044] 3. Gas-liquid dual-fuel mode: In liquid fuel mode, high-pressure air is replaced with high-pressure gaseous fuel. The liquid fuel is atomized by impact pneumatic atomization in mixing chamber 7, which causes the droplets after collision atomization to break up again, so that the gaseous fuel and liquid fuel are highly uniformly mixed and fully combusted in the combustion chamber.

[0045] Example 2

[0046] This embodiment designs a gas turbine with a combustion chamber. A dual-fuel nozzle as described in Embodiment 1 is inserted into the outer wall of the combustion chamber, and the ignition end of the dual-fuel nozzle extends into the combustion chamber.

[0047] The above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation; it is neither necessary nor possible to exhaustively list all possible implementations. However, obvious variations or modifications derived therefrom remain within the scope of this technology.

Claims

1. A dual-fuel nozzle for a gas turbine combustion chamber, characterized in that: The system includes a concentric fuel tube, a liquid fuel nozzle (3), and a mixing cap (4). The concentric fuel tube has a liquid fuel channel (5) and a gas fuel channel (6). The liquid fuel nozzle (3) is connected to the front end of the concentric fuel tube and has a Venturi jet orifice (14) and a gas fuel swirl orifice (8). The Venturi jet orifice (14) is connected to the liquid fuel channel (5), and the gas fuel swirl orifice (8) is connected to the gas fuel channel (6). The mixing cap (4) is installed at the front end of the concentric fuel tube, and a mixing chamber (7) is formed between the mixing cap (4) and the liquid fuel nozzle (3). The liquid fuel can be atomized pneumatically and atomized by collision in the mixing chamber (7) and mixed with gas fuel or air. A mixing fuel external spray hole (13) is provided on the mixing cap (4), and the fuel in the mixing chamber (7) can be sprayed outward through the mixing fuel external spray hole (13). The inner wall of the hybrid cap (4) is provided with a conical collider (12), the tip of which is directly opposite the Venturi jet orifice (14); The cone-shaped collider (12) has a stepped surface at its root that is perpendicular to the axis of the cone-shaped collider (12).

2. The dual-fuel nozzle of the gas turbine combustion chamber according to claim 1, characterized in that: The concentric fuel tube includes a liquid fuel tube (1) and a gas fuel tube (2), with the gas fuel tube (2) coaxially sleeved outside the liquid fuel tube (1); the liquid fuel channel (5) is located inside the liquid fuel tube (1), and the gas fuel channel (6) is located between the liquid fuel tube (1) and the gas fuel tube (2).

3. The dual-fuel nozzle of the gas turbine combustion chamber according to claim 2, characterized in that: The liquid fuel nozzle (3) is sealed to the front end of the liquid fuel pipe (1) and the front end of the gas fuel pipe (2). The Venturi jet orifice (14) is located at the center of the liquid fuel nozzle (3), and the gas fuel swirl orifice (8) is located at the edge of the liquid fuel nozzle (3).

4. The dual-fuel nozzle of the gas turbine combustion chamber according to claim 3, characterized in that: The Venturi jet orifice (14) includes a Venturi contraction orifice section (15), a Venturi throat orifice section (16), and a Venturi expansion orifice section (17). The diameter of the Venturi contraction orifice section (15) is smaller at the front and larger at the back, the diameter of the Venturi expansion orifice section (17) is larger at the front and smaller at the back, and the diameter of the Venturi throat orifice section (16) is the same at the front and back. The small end of the Venturi contraction orifice section (15) and the small end of the Venturi expansion orifice section (17) face each other, and the Venturi throat orifice section (16) is located between the small end of the Venturi contraction orifice section (15) and the small end of the Venturi expansion orifice section (17).

5. The dual-fuel nozzle of the gas turbine combustion chamber according to claim 4, characterized in that: The outlets of the Venturi jet orifice (14) and the gas fuel swirl orifice (8) are located on the same plane.

6. The dual-fuel nozzle for a gas turbine combustion chamber according to any one of claims 3-5, characterized in that: The front end of the gas fuel pipe (2) is externally threaded with a nut (9), and the front end of the nut (9) is fixedly connected to the mixing cap (4); the mixing cap (4) is hemispherical; the inlet of the liquid fuel pipe (1) is located at its rear end and extends outside the rear end of the liquid fuel pipe (1); the inlet of the gas fuel pipe (2) is located on its rear side wall and is perpendicular to the axis of the gas fuel pipe (2).

7. The dual-fuel nozzle for the gas turbine combustion chamber according to claim 1, characterized in that: The mixed fuel external injection hole (13) is a swirling hole; the mixed fuel external injection hole (13) includes a concentric outer ring swirling channel (10) and an inner ring swirling channel (11), the rotation directions of the outer ring swirling channel (10) and the inner ring swirling channel (11) are the same or opposite, and the rotation direction of the gas fuel swirling hole (8) is the same or opposite to the rotation direction of the outer ring swirling channel (10).

8. A gas turbine, characterized in that, A combustion chamber is provided inside the gas turbine, and a dual-fuel nozzle of the gas turbine combustion chamber as described in claim 1 is installed on the outer wall of the combustion chamber, with the ignition end of the dual-fuel nozzle extending into the combustion chamber.

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