Micro gas turbine nozzle with two combustion modes

Abstract

The invention discloses a micro gas turbine nozzle with two combustion modes, which generally comprises a diffusion fuel channel, a premixing fuel channel and a gas premixing channel which are mutually connected into a whole. The nozzle has two combustion modes of diffusive combustion and premixed combustion, air required by combustion comes from two side holes of the gas premixing channel, namely a premixed air hole and a premixed rotational flow groove, and when gas fuel is in contact with the air through the diffusive fuel channel, diffusive combustion flames can be formed through ignition; when gas fuel passes through the premixing combustion channel, the fuel is fully mixed with air in the gas premixing channel to form rotational flow premixing fuel gas, and premixing combustion flames can be formed through ignition.

Description

Technical Field

[0001] The invention relates to the field of micro gas turbine nozzles, and in particular to a gas turbine nozzle with two combustion modes. Background Art

[0002] Micro gas turbine power generation is currently the most mature and commercially competitive distributed power generation equipment, with advantages such as good fuel adaptability, high reliability, environmental friendliness, and ease of use. One of the core components of a gas turbine is the combustion chamber, and the nozzle controls the combustion process inside the entire combustion chamber. It is an important component for regulating the flow and combustion performance of both fuel and air, and plays an important role in the entire unit operation process.

[0003] As a distributed power generation equipment, micro gas turbines are not only easy to use, but also suitable for a variety of load conditions. Therefore, the micro gas turbine itself needs to have the ability to adjust the load. At present, micro gas turbines mostly use premixed combustion to reduce the combustion flame temperature, thereby reducing NO x However, premixed combustion has a small stable combustion area and unstable combustion at low load. To solve this problem, manufacturers propose to add a diffusion combustion mode in the combustion chamber. Diffusion combustion has the advantage of stable combustion at low load. However, adding a new nozzle space to the original combustion chamber will affect the layout and manufacturing process of the entire combustion chamber, and will also change the flow field in the combustion chamber, affecting the combustion results. Summary of the invention

[0004] In order to make up for the shortcomings of the prior art, solve the problem of adding a diffusion combustion mode to a micro gas turbine without changing the original layout of the combustion chamber, reduce the impact of the modified nozzle on the original combustion chamber, simplify the control method of the gas turbine load change, and integrate diffusion combustion and premixed combustion on the same nozzle, the present invention provides a micro gas turbine nozzle with two combustion modes.

[0005] The technical solution of the present invention is:

[0006] A micro gas turbine nozzle with two combustion modes comprises three parts: a diffusion fuel channel, a premixed fuel channel and a gas premixed channel, which are interconnected as one. The nozzle has two combustion modes, namely diffusion combustion and premixed combustion. The air required for combustion comes from two side openings of the gas premixed channel, namely the premixed air hole and the premixed swirl groove. When the gas fuel contacts the air through the diffusion fuel channel, a diffusion combustion flame can be formed after ignition. When the gas fuel passes through the premixed combustion channel, the fuel is fully mixed with the air in the gas premixed channel to form a swirl premixed gas, which can form a premixed combustion flame after ignition.

[0007] Furthermore, the premix fuel channel includes: a premix fuel inlet, a premix fuel channel, a nozzle fixing channel, and a premix fuel outlet device; the gas premix channel includes: a premix air hole, a premix swirl groove, and a gas premix channel.

[0008] Furthermore, the diffusion fuel channel is fixed by both the premix fuel channel and the premix fuel outlet device, and the diffusion fuel channel is coaxial with the gas premix channel; the premix fuel inlet, the premix fuel channel, the nozzle fixing channel, and the premix fuel outlet device are connected in sequence, and the hollow parts of each component constitute the fuel channel; the outer diameter of the premix fuel outlet device coincides with the inner diameter of the gas premix channel.

[0009] Furthermore, the total length of the diffusion fuel channel is 0.93-0.94 times the total length of the nozzle. The purpose is that the gas premixing channel includes the diffusion fuel channel, and the outlets of the two are at a certain distance, ensuring that the air in the gas premixing channel is in full contact with the gas fuel at the outlet of the diffusion fuel channel to avoid incomplete combustion.

[0010] Furthermore, the diffusion fuel channel has the same diameter as the premixed fuel inlet; and the diameter of the gas premixed channel is 5 times that of the diffusion fuel channel.

[0011] Furthermore, the front end of the premixed fuel outlet device is a hollow cone with a curvature of 0.1 to 0.25, and the rear end is a hollow cylinder. When the premixed gas formed by the fuel and the air hits the premixed fuel outlet device, the flow direction will be changed by the cone with a curved surface, and the premixed gas will eventually flow along the curved surface toward the outlet of the gas premixing channel.

[0012] Furthermore, the premixed fuel outlet device has 12 small through holes at a curvature of 0.1 in the hollow cone, and the total area of ​​the small through holes is 0.2 times the premixed fuel inlet area. The flow rate of the gas fuel from the nozzle fixed channel will be significantly increased after passing through the small through holes, which is convenient for subsequent full mixing with air.

[0013] Furthermore, the air for the premixed gas mainly comes from the premixed air holes and the premixed swirl grooves, wherein the premixed air holes are 4 vertical circular holes, and the premixed swirl grooves are 15 rounded rectangular holes with an inclination of 45°;

[0014] Furthermore, the total area of ​​the premixed air hole is 1.28-1.33 times that of the premixed swirl groove. The air at the outlet of the premixed air hole is the premixed main body, which is fully in contact with the fuel for preliminary mixing. The air at the outlet of the premixed swirl groove has a certain degree of swirl, which drives the premixed gas to swirl. The premixed gas after swirl has a better mixing effect and shortens the flame length.

[0015] Furthermore, the standard root mean square S is used as the standard for judging the uniformity of premixing. The standard root mean square S of the premixing at the nozzle outlet should be less than 0.05 to be considered that the fuel and air are mixed uniformly. The specific calculation method is as follows:

[0016]

[0017] c is the concentration, and n is the number of data points selected for calculation.

[0018] The beneficial effects of the present invention are:

[0019] 1. The micro gas turbine nozzle of the present invention has two combustion modes. When the gas fuel passes through the diffusion fuel channel, after contacting with the air at the channel outlet, it can form a diffusion combustion flame after ignition, which is suitable for low-load combustion; when the gas fuel passes through the premixed combustion channel, the fuel will be fully mixed with the air in the gas premixed channel to form a swirl premixed gas, which can form a premixed combustion flame after ignition, which is suitable for medium and high load combustion.

[0020] 2. The micro gas turbine nozzle of the present invention integrates the diffusion combustion channel and the premixed combustion channel into one nozzle, which saves the use space of the combustion chamber and simplifies the layout of the combustion chamber. At the same time, the design of the diffusion combustion channel has basically no effective influence on the premixing effect of the premixed gas.

[0021] 3. The micro gas turbine nozzle of the present invention has a premixing standard root mean square S of the premixed gas at the nozzle outlet that is less than 0.05, which meets the requirement of premixing uniformity. At the same time, the premixed gas has a swirl characteristic, which can effectively reduce the flame length. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0023] Figure 2 It is a half-section schematic diagram of the overall structure of the present invention;

[0024] Figure 3 Schematic diagram and cross-sectional view of the gas premixing channel of the present invention;

[0025] Figure 4 A side view of the premixed fuel outlet device of the present invention;

[0026] 1 diffusion combustion channel, 2 premixed fuel inlet, 3 premixed fuel channel, 4 nozzle fixing channel, 5 premixed fuel outlet device, 6 gas premixing channel, 6-1 premixed air hole, 6-2 premixed swirl groove; DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. The described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] It should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0029] Example

[0030] like Figure 1-4 As shown, the present invention provides a micro gas turbine nozzle with two combustion modes, which generally includes: a diffusion fuel channel, a premixed fuel channel, and a gas premixed channel, which are interconnected as a whole. The nozzle has two combustion modes: diffusion combustion and premixed combustion. The air required for combustion comes from two side openings of the gas premixed channel, namely the premixed air hole 6-1 and the premixed swirl groove 6-2. When the gas fuel contacts the air through the diffusion fuel channel, a diffusion combustion flame can be formed after ignition; when the gas fuel passes through the premixed combustion channel, the fuel is fully mixed with the air in the gas premixed channel to form a swirl premixed gas, which can form a premixed combustion flame after ignition. Its three major parts are characterized in that the diffusion fuel channel includes: a diffusion fuel channel 1; the premixed fuel channel includes: a premixed fuel inlet 2, a premixed fuel channel 3, a nozzle fixing channel 4, and a premixed fuel outlet device 5; the gas premixed channel includes: a premixed air hole 6-1, a premixed swirl groove 6-2, and a gas premixed channel 6;

[0031] In this embodiment, the diffusion fuel channel 1 is fixed by both the premixed fuel channel 3 and the premixed fuel outlet device 5, and the diffusion fuel channel 1 is coaxial with the gas premixed channel 6; the premixed fuel inlet 2, the premixed fuel channel 3, the nozzle fixing channel 4, and the premixed fuel outlet device 5 are connected in sequence, and the hollow parts of each component constitute the fuel channel; the outer diameter of the premixed fuel outlet device 5 coincides with the inner diameter of the gas premixed channel 6.

[0032] In this embodiment, the total length of the diffusion fuel channel 1 is 0.93-0.94 times the total length of the nozzle. The purpose is that the gas premixing channel 6 includes the diffusion fuel channel 1, and the outlets of the two are at a certain distance, so as to ensure that the air in the gas premixing channel 6 is in full contact with the gas fuel at the outlet of the diffusion fuel channel 1 to avoid incomplete combustion.

[0033] In this embodiment, the diffusion fuel channel 1 and the premix fuel inlet 2 have the same diameter; the diameter of the gas premix channel 6 is 5 times that of the diffusion fuel channel 1 .

[0034] In this embodiment, the front end of the premixed fuel outlet device 5 is a hollow cone with a curvature of 0.1 to 0.25, and the rear end is a hollow cylinder;

[0035] In this embodiment, the hollow cone of the premixed fuel outlet device 5 is provided with 12 small through holes at a curvature of 0.1, and the total area of ​​the small through holes is 0.2 times the area of ​​the premixed fuel inlet 2. After the gas fuel from the nozzle fixed channel 4 passes through the small through holes, the flow rate will be significantly increased, which is convenient for subsequent mixing with air.

[0036] In this embodiment, the air for premixing the gas mainly comes from the premixing air holes 6-1 and the premixing swirl grooves 6-2, wherein the premixing air holes 6-1 are 4 vertical circular holes, and the premixing swirl grooves 6-2 are 15 rounded rectangular holes with an inclination of 45°;

[0037] In this embodiment, the total area of ​​the premixed air hole 6-1 is 1.28-1.33 times that of the premixed swirl groove 6-2. The air at the outlet of the premixed air hole is the premixed main body, which is fully in contact with the fuel for preliminary mixing. The air at the outlet of the premixed swirl groove has a certain degree of swirl, which drives the premixed gas to swirl. The premixed gas after swirl has a better mixing effect and shortens the flame length.

[0038] In this embodiment, the standard root mean square S is used as the standard for judging the premixing uniformity. The standard root mean square S of the premixing at the nozzle outlet should be less than 0.05 to be considered that the fuel and air are mixed uniformly. The specific calculation method is as follows:

[0039]

[0040] c is the concentration, and n is the number of data points selected for calculation.

[0041] The contents not described in detail in this specification belong to the prior art of professionals in this field.

[0042] The embodiments and principles described above have provided a detailed description of the technical solutions of the present invention. For those skilled in the art, they can still modify the technical solutions recorded in the aforementioned embodiments, or make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A micro gas turbine nozzle with two combustion modes, characterized in that: include: The nozzle consists of three parts: a diffusion fuel channel, a premixed fuel channel, and a gas premixed channel, which are interconnected as a whole; the nozzle has two combustion modes, namely diffusion combustion and premixed combustion. The air required for combustion comes from two side openings of the gas premixed channel, namely the premixed air hole and the premixed swirl groove. When the gas fuel contacts the air through the diffusion fuel channel, a diffusion combustion flame can be formed after ignition; when the gas fuel passes through the premixed combustion channel, the fuel is fully mixed with the air in the gas premixed channel to form a swirl premixed gas, which can form a premixed combustion flame after ignition.

2. A micro gas turbine nozzle with two combustion modes according to claim 1, characterized in that: The premix fuel channel comprises: a premix fuel inlet, a premix fuel channel, a nozzle fixing channel, and a premix fuel outlet device; the gas premix channel comprises: the premix air hole, the premix swirl groove, and the gas premix channel.

3. A micro gas turbine nozzle with two combustion modes according to claim 2, characterized in that: The diffusion fuel channel is fixed by both the premix fuel channel and the premix fuel outlet device, and the diffusion fuel channel is coaxial with the gas premix channel; the premix fuel inlet, the premix fuel channel, the nozzle fixing channel, and the premix fuel outlet device are connected in sequence, and the hollow parts of each component constitute the fuel channel; the outer diameter of the premix fuel outlet device coincides with the inner diameter of the gas premix channel.

4. The micro gas turbine nozzle with two combustion modes according to claim 3, characterized in that: The total length of the diffusion fuel channel is 0.93-0.94 times the total length of the nozzle. The gas premixing channel includes the diffusion fuel channel, and the outlets of the two are at a certain distance, ensuring that the air in the gas premixing channel is in full contact with the gas fuel at the outlet of the diffusion fuel channel to avoid incomplete combustion.

5. The micro gas turbine nozzle with two combustion modes according to claim 2, characterized in that: The diameter of the diffusion fuel channel is the same as that of the premixed fuel inlet; the diameter of the gas premixed channel is 5 times that of the diffusion fuel channel.

6. The micro gas turbine nozzle with two combustion modes according to claim 2, characterized in that: The front end of the premixed fuel outlet device is a hollow cone with a curvature of 0.1 to 0.25, and the rear end is a hollow cylinder.

7. A micro gas turbine nozzle with two combustion modes according to claim 6, characterized in that: Twelve small through holes are set at the position where the curvature of the hollow cone is 0.1, and the total area of ​​the small through holes is 0.2 times the area of ​​the premixed fuel inlet.

8. A micro gas turbine nozzle with two combustion modes according to claim 1 or 2, characterized in that: The premixed air holes are 4 vertical circular holes, and the premixed swirl grooves are 15 rounded rectangular holes with an inclination of 45°.

9. The micro gas turbine nozzle with two combustion modes according to claim 8, characterized in that: The total area of ​​the premixed air holes is 1.28-1.33 times that of the premixed swirl groove. The air at the outlet of the premixed air holes is the premixed main body, which is in full contact with the fuel for preliminary mixing. The air at the outlet of the premixed swirl groove has a certain degree of swirl, which drives the premixed gas to swirl. The premixed gas that has undergone swirl has a better mixing effect and shortens the flame length.

10. The micro gas turbine nozzle with two combustion modes according to claim 1, characterized in that: The standard root mean square S is used as the standard for judging the premixing uniformity. The premixing standard root mean square S at the nozzle outlet should be less than 0.05 to be considered that the fuel and air are mixed uniformly. The specific calculation method is as follows: c is the concentration, and n is the number of data points selected for calculation.

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