Fuel line and nozzle therefor

Abstract

The application discloses a fuel pipeline and a nozzle thereof, and relates to the technical field of the nozzle.The nozzle body;the inside of the nozzle body is formed with a gas fuel cavity and an air cavity which are not communicated with each other; a plurality of gas fuel injection holes and a first opening are arranged on the nozzle body, the gas fuel injection holes are communicated with the gas fuel cavity; the first opening is communicated with the gas fuel cavity; air outlet holes are arranged on the nozzle body and correspond to the plurality of gas fuel injection holes one by one, and the air ejected from the air outlet holes is used for covering the corresponding gas fuel injection holes.The high-pressure air ejected from the air outlet holes can cover and block the gas fuel injection holes through the design of the air outlet holes.When the gas fuel injection holes are idle, the fuel in the combustion chamber cannot enter the gas fuel cavity or the gas fuel flow channel through the gas fuel injection holes.There is no need to design an auxiliary device or a complex control system for blowing and cleaning the gas fuel flow channel.

Description

TECHNICAL FIELD

[0001] The present application relates to the nozzle technical field, specifically to a fuel pipeline and a nozzle thereof. BACKGROUND

[0002] A gas turbine is an internal combustion power machine that uses continuous flow gas as working medium to drive the turbine to rotate at high speed and convert the energy of fuel into useful work. Generally, a gas turbine includes a compressor, a combustion chamber and a turbine and other components. The nozzle is a key component in the combustion chamber of the gas turbine, which is used to inject fuel into the combustion chamber for combustion to release energy in the form of high-temperature gas. In order to improve the practicability of the gas turbine, a dual-fuel gas turbine that can burn both liquid fuel and gaseous fuel has appeared on the market. In order to match the dual-fuel gas turbine, a dual-fuel nozzle has also appeared on the market, which is a nozzle that can inject both liquid fuel and gaseous fuel, as the name implies.

[0003] It needs to be clear that when the dual-fuel gas turbine is working, it can only use gaseous fuel or liquid fuel. That is, during the operation of the dual-fuel gas turbine, one of the fuel flow channels is idle. If the internal pressure of the idle fuel flow channel is less than the pressure in the combustion chamber, it will inevitably cause the fuel in the combustion chamber to backflow, which may cause the fuel to clog the flow channel due to coking, or even cause the fuel to explode in the fuel flow channel and damage the gas turbine. Therefore, in the prior art, a cleaning blow pipeline is designed to use clean blow gas to clean the idle fuel flow channel to block the backflow of fuel. Designing an additional cleaning blow pipeline not only increases the auxiliary equipment and cost, but also requires a complex control system to realize gas path switching. SUMMARY

[0004] The purpose of the present application is to provide a fuel pipeline and a nozzle thereof to solve the technical problem of the prior art that the idle fuel flow channel needs to be cleaned and blown, which requires additional design of a cleaning blow pipeline, increasing the auxiliary equipment and cost.

[0005] To achieve the above-mentioned purpose, the present application provides the following technical solutions:

[0006] In a first aspect, the present application provides a nozzle, which comprises: a nozzle body; a gaseous fuel cavity and an air cavity formed in the interior of the nozzle body and not connected to each other; a plurality of gaseous fuel injection holes and a first opening provided in the nozzle body, the gaseous fuel injection holes being in communication with the gaseous fuel cavity; the first opening being in communication with the gaseous fuel cavity; an air outlet hole provided in the nozzle body and corresponding to each gaseous fuel injection hole, the air outlet hole being used to cover the corresponding gaseous fuel injection hole, the air outlet hole being in communication with the air cavity; a second opening provided in the nozzle body; and the second opening being in communication with the air cavity.

[0007] As an embodiment of the present application, the normal direction of the air outlet hole is perpendicular to the axial direction of the corresponding gas fuel injection hole.

[0008] As an embodiment of the present application, the inside of the nozzle body is further provided with a liquid fuel cavity, the liquid fuel cavity, the gas fuel cavity and the air cavity are not communicated with each other; a plurality of liquid fuel injection holes and a third opening are provided in the nozzle body, the liquid fuel injection holes are communicated with the liquid fuel cavity; the third opening is communicated with the liquid fuel cavity.

[0009] As an embodiment of the present application, the nozzle body is cylindrical, a plurality of liquid fuel injection holes are uniformly distributed at equal intervals around the axial line of the nozzle body; a plurality of gas fuel injection holes are uniformly distributed at equal intervals around the axial line of the nozzle body.

[0010] As an embodiment of the present application, the air outlet hole is a long strip-shaped hole; the width direction of the air outlet hole is parallel to the axial direction of the corresponding gas fuel injection hole; the length direction of the air outlet hole is perpendicular to the axial direction of the corresponding gas fuel injection hole.

[0011] As an embodiment of the present application, the third opening and the first opening are both circular holes, and the axial lines of the third opening and the first opening coincide.

[0012] The second aspect of the present application provides a fuel pipeline comprising the nozzle according to any one of the first aspect.

[0013] As an embodiment of the present application, the fuel pipeline further comprises: a fuel main pipe, the fuel main pipe is provided with a liquid fuel flow channel and a gas fuel flow channel which are not communicated with each other, wherein the liquid fuel flow channel is communicated with the liquid fuel cavity through the third opening; the gas fuel flow channel is communicated with the gas fuel cavity through the first opening; a liquid fuel inlet pipe is communicated with the liquid fuel flow channel; a first gas fuel inlet pipe is communicated with the gas fuel flow channel.

[0014] As an embodiment of the present application, a second gas fuel inlet pipe is further provided, which is communicated with the liquid fuel flow channel, and the distance between the second gas fuel inlet pipe and the nozzle is greater than the distance between the liquid fuel inlet pipe and the nozzle.

[0015] As an embodiment of the present application, a first one-way valve is arranged on the second gas fuel inlet pipe, and a second one-way valve is arranged on the liquid fuel inlet pipe.

[0016] Compared with the prior art, the present application has the following beneficial effects:

[0017] The high pressure air jetted from the air outlet hole can cover the gas fuel injection hole. When the gas fuel injection hole is idle, the fuel in the combustion chamber cannot enter the gas fuel cavity or the gas fuel flow channel through the gas fuel injection hole. There is no need to design additional equipment or complex control system to blow the gas fuel flow channel, and the cost is relatively low. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 A perspective view of the nozzle according to an embodiment of the present application;

[0019] Figure 2 A sectional view of the nozzle according to an embodiment of the present application;

[0020] Figure 3 A partial sectional view of the nozzle according to an embodiment of the present application without liquid fuel cavity;

[0021] Figure 4 A right view of the nozzle according to an embodiment of the present application without liquid fuel cavity;

[0022] Figure 5 A left view of the nozzle according to an embodiment of the present application without liquid fuel cavity;

[0023] Figure 6 A flow diagram of the high pressure air according to an embodiment of the present application;

[0024] Figure 7 A perspective view of the fuel pipeline according to an embodiment of the present application;

[0025] Figure 8 A sectional view of the fuel pipeline according to an embodiment of the present application.

[0026] In the drawings: 1, fuel main pipe; 11, liquid fuel flow channel; 12, gas fuel flow channel; 2, second gas fuel inlet pipe; 3, liquid fuel inlet pipe; 4, first gas fuel inlet pipe; 5, nozzle; 51, liquid fuel cavity; 52, gas fuel cavity; 53, air cavity; 54, liquid fuel injection hole; 55, gas fuel injection hole; 56, second opening; 57, air outlet hole; 58, first opening; 59, third opening; 6, first one-way valve; 7, second one-way valve. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0028] It should be noted that in the description of this application, the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0029] Furthermore, it should be understood that, for ease of description, the dimensions of the various components shown in the accompanying drawings are not drawn to actual scale; for example, the thickness or width of some layers may be exaggerated relative to other layers.

[0030] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined or described in one figure, it will not need to be discussed or described in detail in the description of the subsequent figures.

[0031] like Figures 1 to 6 As shown, this application proposes a nozzle. The nozzle 5 includes: a nozzle body; the interior of the nozzle body has a gas fuel chamber 52 and an air chamber 53 that are not interconnected.

[0032] Specifically, the gas fuel chamber 52 is used to transport gaseous fuel, while the air chamber 53 is used to transport air. It should be understood that, in the embodiments of this application, the air introduced into the air chamber 53 can come from external equipment of the gas turbine, such as an air compressor or air storage tank. To save production costs, in another embodiment of this application, the air introduced into the air chamber 53 comes from the compressor in the gas turbine.

[0033] In order for the nozzle body to spray gaseous fuel normally, such as Figure 2 and Figure 5 As shown, the nozzle body also has multiple gaseous fuel injection holes 55, which are connected to the gaseous fuel chamber 52. The main function of the gaseous fuel injection holes 55 is to allow the high-pressure gaseous fuel in the gaseous fuel chamber 52 to be injected into the combustion chamber through the gaseous fuel injection holes 55. At the same time, the nozzle body also needs to have a first opening 58, which is connected to the gaseous fuel chamber 52. The first opening 58 is mainly used to connect to an external gaseous fuel passage, such as the gaseous fuel flow channel 12 in the embodiment below.

[0034] It is to be noted that, in the embodiment of the present application, in order to prevent fuel in the combustion chamber from flowing back to the gas fuel cavity 52 or the gas fuel flow channel 12 through the gas fuel injection hole 55 when the gas fuel injection hole 55 is idle. In the embodiment, the nozzle body is further provided with air outlet holes 57 corresponding to the plurality of gas fuel injection holes 55, and the air outlet holes 57 are in communication with the air cavity 53. The main function of the air outlet holes 57 is to output high-pressure air in the air cavity 53 to cover the corresponding gas fuel injection hole 55. In order to enable the air outlet holes 57 to continuously output air, the nozzle body is further provided with a second opening 56 in the embodiment of the present application, and the second opening 56 is in communication with the air cavity 53. The second opening 56 is mainly used to connect with external air equipment, such as the air compressor, the air storage tank, or the air compressor in the above embodiment.

[0035] As shown in Figure 3 and Figure 6 , high-pressure air enters the air cavity 53 through the second opening 56 and is sprayed out of the air cavity 53 through the air outlet holes 57. It is to be noted that the flow route of the high-pressure air is as shown in route A of Figure 6 or route C of Figure 3 , and the high-pressure air sprayed out of the air outlet holes 57 can cover the gas fuel injection hole 55. It is to be noted that the fuel in the combustion chamber can only enter the gas fuel cavity 52 through the gas fuel injection hole 55, as shown in route B of Figure 6 . Since the high-pressure air sprayed out of the air outlet holes 57 can cover the gas fuel injection hole 55, that is, route B is cut off, fuel backflow to the air cavity 53 can be effectively prevented.

[0036] Compared with the need to design a relatively complex blowpipe to blow the gas fuel flow channel 12, in the embodiment of the present application, only high-pressure air (for example, compressor bleed air) needs to be introduced into the second opening 56. The design is simple, does not need to increase additional auxiliary equipment, does not need to design a complex control system, and has a low cost.

[0037] It is to be noted that, in an embodiment of the present application, in order to ensure the strength of the nozzle 5 itself, as shown in Figure 1 and Figure 2As shown, the air cavity 53 can be designed as multiple independent chambers, each of which is equipped with a second opening 56 and an air outlet hole 57. It is easy to imagine that in another embodiment of the present application, the gaseous fuel cavity 52 and the liquid fuel cavity 51 described below can also be designed as multiple independent chambers. If the gaseous fuel cavity 52 and the liquid fuel cavity 51 are also multiple independent chambers, each gaseous fuel cavity 52 needs to be provided with a corresponding first opening 58; each liquid fuel cavity 51 needs to be provided with a corresponding third opening 59, which will not be described in detail here. In other embodiments of the present application, the multiple air cavities 53 in the embodiments of the present application can also be designed as a cavity that communicates with each other. If there is only one cavity, only one second opening 56 needs to be designed, which will not be described in detail here.

[0038] It needs to be clear that the nozzle body in the embodiments of the present application can be a nozzle of any shape and structure, which is not limited. In a specific embodiment of the present application, as shown in Figure 6 As shown, the axis of the gaseous fuel injection hole 55 can be parallel to the axis of the nozzle body. However, in order for the gaseous fuel to be uniformly dispersed, in another embodiment of the present application, multiple gaseous fuel injection holes 55 are uniformly distributed at equal distances around the axis of the nozzle body, and the axes of any two gaseous fuel injection holes 55 are not coplanar (i.e. not parallel). Thus, the gaseous fuel ejected through the gaseous fuel injection hole 55 can form a swirling flow, making the dispersion of gaseous fuel more uniform. The liquid fuel injection hole 54 described below can also be designed in this way, which will not be described in detail later.

[0039] It needs to be clear that in the embodiments of the present application, the air outlet hole 57 can be of any shape and structure, as long as the high-pressure air ejected through the air outlet hole 57 can cover the gaseous fuel injection hole 55. For example: the air outlet hole 57 can be a circular hole, a triangular hole or a square hole, etc.

[0040] In a specific embodiment of the present application, in order to make the high-pressure air ejected from the air outlet hole 57 have a better covering effect, i.e. have a larger covering area, the air outlet hole 57 is a long strip-shaped hole. It needs to be clear that when the high-pressure air is ejected from the air outlet hole 57, the ejection direction of the high-pressure air is always parallel to the normal direction of the air outlet hole 57. As shown in Figure 6 If the normal direction of the air outlet hole 57 is horizontal, the ejection direction of the high-pressure air through the air outlet hole 57 is also horizontal.

[0041] It is easy to imagine that if the direction of the high-pressure air jet is perpendicular to the axis direction of the hole to be covered, the covering effect of the high-pressure air is the best. Therefore, in an embodiment of the present application, the air outlet hole 57 is a long strip-shaped hole. The width direction of the air outlet hole 57 is parallel to the axial direction of the corresponding gas fuel injection hole 55, and the length direction of the air outlet hole 57 is perpendicular to the axial direction of the corresponding gas fuel injection hole 55. It should be noted that both the width direction and the length direction of the air outlet hole 57 are perpendicular to the normal direction thereof, which will not be described in detail here.

[0042] In order to make the nozzle 5 have a liquid fuel delivery function. In an embodiment of the present application, as shown in Figure 1 and Figure 2 , a plurality of liquid fuel injection holes 54 are also formed on the nozzle body, and the liquid fuel injection holes 54 are in communication with the liquid fuel chamber 51. The main function of the liquid fuel injection hole 54 is that the high-pressure liquid fuel in the liquid fuel chamber 51 can be jetted into the combustion chamber through the liquid fuel injection hole 54. At the same time, a third opening 59 also needs to be formed on the nozzle body, and the third opening 59 is in communication with the liquid fuel chamber 51. The third opening 59 is mainly used to connect with the external liquid fuel channel, for example, the liquid fuel flow channel 11 in the embodiment below.

[0043] It should be noted that in the embodiments of the present application, the shape and structure of the first opening 58 and the third opening 59 are not limited. When using the nozzle 5 provided by the embodiments of the present application, one gas fuel pipeline can be connected with the first opening 58, and one liquid fuel pipeline can be connected with the third opening 59. As shown in Figure 2 and Figure 8 , in an embodiment of the present application, in order to reduce the number of pipelines, the third opening 59 and the first opening 58 in the nozzle 5 are both circular holes, and the axial lines of the third opening 59 and the first opening 58 coincide. As shown in Figure 8 , by using the nozzle 5 with such a structure, one fuel main pipeline 1 can be used to deliver two kinds of fuel.

[0044] The nozzle in the embodiments of the present application is designed through the air outlet hole, so that the high-pressure air jetted from the air outlet hole can cover and block the gas fuel injection hole. When the gas fuel injection hole is idle, the fuel in the combustion chamber cannot enter the gas fuel chamber or the gas fuel flow channel through the gas fuel injection hole. Without the need to design an auxiliary device or a complex control system for purging the gas fuel flow channel, the cost is relatively low.

[0045] After introducing the embodiments of the nozzle of the present application, a fuel pipeline proposed by the present application will be introduced below. Specifically, as shown in Figure 7 and Figure 8 , the fuel pipeline uses the nozzle in any one of the embodiments proposed by the present application.

[0046] It should be noted that, in a specific embodiment of the present application, in order to make the fuel pipeline relatively simple. As shown in Figure 8 the fuel pipeline includes: fuel main pipe 1, liquid fuel inlet pipe 3 and first gas fuel inlet pipe 4. Specifically, the fuel main pipe 1 is provided with liquid fuel flow channel 11 and gas fuel flow channel 12 which are not communicated with each other, wherein the liquid fuel flow channel 11 is communicated with the liquid fuel cavity 51 through the third opening 59; the gas fuel flow channel 12 is communicated with the gas fuel cavity 52 through the first opening 58. That is, in the embodiment of the present application, two forms of fuel (i.e. gas fuel and liquid fuel) can be transported through the fuel main pipe 1. It is used for cooperating with the nozzle 5 capable of transporting gas fuel and liquid fuel proposed in the above embodiment of the present application.

[0047] It should be noted that, in order to be able to normally transport gas fuel and liquid fuel. In the embodiment of the present application, the liquid fuel inlet pipe 3 is communicated with the liquid fuel flow channel 11; the first gas fuel inlet pipe 4 is communicated with the gas fuel flow channel 12. The liquid fuel located outside the combustion chamber can enter the combustion chamber in turn through the liquid fuel inlet pipe 3, the liquid fuel flow channel 11 and the nozzle 5; the gas fuel located outside the combustion chamber can enter the combustion chamber in turn through the first gas fuel inlet pipe 4, the gas fuel flow channel 12 and the nozzle 5.

[0048] It should be noted that, although the nozzle 5 in the embodiment of the present application can prevent the fuel in the combustion chamber from entering the nozzle 5 when the gas fuel injection hole is idle. However, it cannot prevent the fuel in the combustion chamber from entering the nozzle 5 when the liquid fuel injection hole 54 is idle. In a specific embodiment of the present application, in order to prevent the fuel in the combustion chamber from entering the nozzle 5 when the liquid fuel injection hole 54 is idle. As shown in Figure 7 and Figure 8 the fuel pipeline further includes a second gas fuel inlet pipe 2, and the second gas fuel inlet pipe 2 is communicated with the liquid fuel flow channel 11.

[0049] Specifically, when the liquid fuel flow channel 11 is idle (i.e. the combustion chamber burns gas fuel), gas fuel can be input into the liquid fuel flow channel 11 through the second gas fuel inlet pipe 2, and the input gas fuel can blow the liquid fuel flow channel 11.

[0050] In order to be able to remove all liquid fuel in the liquid fuel flow channel 11 by gas fuel when the liquid fuel flow channel 11 is idle, so as to prevent the liquid fuel from coking in the liquid fuel flow channel 11. In a specific embodiment of the present application, as shown in Figure 7 and Figure 8As shown, the distance between the second gas fuel inlet pipe 2 and the nozzle 5 is greater than the distance between the liquid fuel inlet pipe 3 and the nozzle 5. That is, when the gas fuel is input to the liquid fuel flow channel 11 through the second gas fuel inlet pipe 2, the path of the gas fuel covers the path of the liquid fuel, so that the purging is more thorough.

[0051] It should be noted that, in order to prevent the gas fuel from flowing back into the liquid fuel inlet pipe 3 when the gas turbine uses the gas fuel, in one specific embodiment of the present application, the liquid fuel inlet pipe 3 is provided with a second one-way valve 7. The main function of the second one-way valve 7 is to prevent the gas fuel in the liquid fuel flow channel 11 from flowing back into the liquid fuel inlet pipe 3, without hindering the liquid fuel in the liquid fuel inlet pipe 3 from entering the liquid fuel flow channel 11.

[0052] Meanwhile, it should be noted that, in order to prevent the liquid fuel from flowing back into the second gas fuel inlet pipe 2 when the gas turbine uses the liquid fuel, in another embodiment of the present application, the second gas fuel inlet pipe 2 is provided with a first one-way valve 6. The main function of the first one-way valve 6 is to prevent the liquid fuel in the liquid fuel flow channel 11 from flowing back into the second gas fuel inlet pipe 2, without hindering the gas fuel in the second gas fuel inlet pipe 2 from entering the liquid fuel flow channel 11.

[0053] The fuel pipeline in the embodiments of the present application, through the design of the air outlet hole on the nozzle, enables the high-pressure air jetted from the air outlet hole to cover and block the gas fuel injection hole. When the gas fuel injection hole is idle, the fuel in the combustion chamber cannot enter the gas fuel cavity or the gas fuel flow channel through the gas fuel injection hole. Through the design of the second gas fuel inlet pipe, the liquid fuel flow channel can be purged by the gas fuel, preventing the fuel in the combustion chamber from entering the liquid fuel cavity or the liquid fuel flow channel through the liquid fuel injection hole. Without the need to design additional equipment or complex control systems for purging the gas fuel flow channel or the liquid fuel flow channel, the cost is relatively low.

[0054] Although the embodiments of the present application have been shown and described, it should be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to the embodiments without departing from the principles and spirit of the present application, and the scope of the present application is defined by the appended claims and their equivalents.

Claims

1. A nozzle characterized by, Comprising: a nozzle body; a gas fuel cavity (52) and an air cavity (53) are formed in the interior of the nozzle body and are not communicated with each other; a plurality of gas fuel injection holes (55) and a first opening (58) are opened in the nozzle body, the gas fuel injection holes (55) are communicated with the gas fuel cavity (52); the first opening (58) is communicated with the gas fuel cavity (52); air outlet holes (57) are opened in the nozzle body and correspond to the plurality of gas fuel injection holes (55) one by one, air sprayed by the air outlet holes (57) is used to cover the corresponding gas fuel injection holes (55), the air outlet holes (57) are communicated with the air cavity (53); a second opening (56) is opened in the nozzle body; the second opening (56) is communicated with the air cavity (53); a liquid fuel cavity (51) is further opened in the interior of the nozzle body, the liquid fuel cavity (51), the gas fuel cavity (52) and the air cavity (53) are not communicated with each other; a plurality of liquid fuel injection holes (54) and a third opening (59) are opened in the nozzle body, the liquid fuel injection holes (54) are communicated with the liquid fuel cavity (51); the third opening (59) is communicated with the liquid fuel cavity (51); the normal direction of the air outlet hole (57) is perpendicular to the axial direction of the corresponding gas fuel injection hole (55).

2. The nozzle of claim 1, wherein The nozzle body is in a cylindrical shape, the plurality of liquid fuel injection holes (54) are uniformly distributed at equal intervals around the axial line of the nozzle body; the plurality of gas fuel injection holes (55) are uniformly distributed at equal intervals around the axial line of the nozzle body.

3. A nozzle according to claim 1 or 2, characterised in that The air outlet hole (57) is an elongated hole; the width direction of the air outlet hole (57) is parallel to the axial direction of the corresponding gas fuel injection hole (55); the length direction of the air outlet hole (57) is perpendicular to the axial direction of the corresponding gas fuel injection hole (55).

4. The nozzle of claim 1 or 2, wherein The third opening (59) and the first opening (58) are both circular holes, and the axial lines of the third opening (59) and the first opening (58) coincide.

5. A fuel line, characterized by Comprising the nozzle as claimed in any one of claims 1 to 4.

6. The fuel line of claim 5, wherein, Further comprising: a fuel main pipeline (1), a liquid fuel flow channel (11) and a gas fuel flow channel (12) are opened in the fuel main pipeline (1) and are not communicated with each other, wherein the liquid fuel flow channel (11) is communicated with the liquid fuel cavity (51) through the third opening (59); the gas fuel flow channel (12) is communicated with the gas fuel cavity (52) through the first opening (58); a liquid fuel inlet pipeline (3) is communicated with the liquid fuel flow channel (11); a first gas fuel inlet pipeline (4) is communicated with the gas fuel flow channel (12).

7. The fuel line of claim 6, wherein Further comprising a second gas fuel inlet pipeline (2) which is communicated with the liquid fuel flow channel (11), the distance between the second gas fuel inlet pipeline (2) and the nozzle is greater than the distance between the liquid fuel inlet pipeline (3) and the nozzle.

8. The fuel line of claim 7, wherein, A first one-way valve (6) is arranged on the second gas fuel inlet pipeline (2), and a second one-way valve (7) is arranged on the liquid fuel inlet pipeline (3).

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