Dual-fuel nozzle for small aero-engine

Abstract

The invention relates to the technical field of small aero-engine combustion devices, in particular to a dual-fuel nozzle for a small aero-engine. The device is characterized by comprising a gaseous fuel header pipe and a liquid fuel header pipe, a gaseous fuel inlet pipe and a gaseous fuel branch pipe are arranged on the gaseous fuel header pipe, a liquid fuel inlet pipe and a liquid fuel branch pipe are arranged on the liquid fuel header pipe, and a liquid fuel nozzle is arranged at the end of the liquid fuel branch pipe. And the end part of the gaseous fuel branch pipe is connected with a liquid fuel nozzle through a gaseous fuel adapter. The liquid fuel pipeline and the gaseous fuel pipeline are combined, the engine adopts gaseous fuel and is easy to ignite and start during starting ignition and low working conditions, and the fuel is switched and the liquid fuel is adopted after the engine enters a slow state, so that a fuel distributor is not needed, oxygen supplementation ignition is not needed, and the cost is reduced. The ignition performance of the small aero-engine combustion chamber is improved, and the complexity and the structural weight of an accessory pipeline system are reduced.

Description

Technical Field

[0001] This invention relates to the field of combustion device technology for small aircraft engines, and more particularly to a dual-fuel nozzle for small aircraft engines. Background Technology

[0002] Currently, due to the pursuit of small and short combustors in small aircraft engines, their unique structural forms often employ recirculation or deflection combustors, with direct flow being less common. Deflection combustors utilize a slinger for fuel supply, while recirculation combustors typically employ two fuel supply lines. Fuel is supplied by the first fuel line during ignition and low-operation conditions, while both lines supply fuel simultaneously after reaching idle. This is primarily because small engines have a low fuel supply volume; using a single fuel line would result in even smaller fuel supply from a single nozzle, lower fuel pressure, and poorer atomization, posing significant challenges for starting and low-operation conditions, especially during high-altitude starts, often requiring additional oxygen for supplemental oxygen. Due to the small nozzle size, it's impossible to implement main and auxiliary fuel lines within the nozzle like in larger engines to address these issues. Therefore, a split fuel supply system is often used to resolve the conflict between high-temperature distribution and low-temperature combustion efficiency. However, this necessitates the use of a fuel distributor in the fuel system, complicating engine accessory piping and increasing system costs. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide a dual-fuel nozzle for small aero engines. It combines liquid fuel lines and gaseous fuel lines, eliminating the need for a fuel distributor and oxygen supplementation ignition, thereby improving the ignition performance of the combustion chamber of small aero engines and reducing the complexity and structural weight of accessory piping systems.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a dual-fuel nozzle for a small aircraft engine, characterized in that it includes a gaseous fuel main pipe and a liquid fuel main pipe, wherein the gaseous fuel main pipe is provided with a gaseous fuel inlet pipe and a gaseous fuel branch pipe, and the liquid fuel main pipe is provided with a liquid fuel inlet pipe and a liquid fuel branch pipe, wherein a liquid fuel nozzle is provided at the end of the liquid fuel branch pipe, and the end of the gaseous fuel branch pipe is connected to the liquid fuel nozzle through a gaseous fuel adapter.

[0005] Furthermore, the liquid fuel nozzle includes a liquid fuel nozzle sleeve, and a first swirling core and a second swirling core are provided inside the liquid fuel nozzle sleeve. The first swirling core and the second swirling core respectively constitute a swirling chamber. A swirling groove is provided on the first swirling core along the circumferential direction at the edge of the swirling chamber, and an injection hole is provided on the second swirling core at the axial position of the swirling chamber. The liquid fuel branch pipe is connected to the liquid fuel nozzle sleeve. The end of the liquid fuel branch pipe extending into the liquid fuel nozzle sleeve is connected to the first swirl core. An oil outlet hole is provided on the pipe wall of the liquid fuel branch pipe extending into the liquid fuel nozzle sleeve. The gaseous fuel adapter includes an outer sleeve with a gas collecting chamber. A swirl sleeve is provided inside the outer sleeve. The outer sleeve is connected to the gaseous fuel branch pipe, and the swirl sleeve is connected to the liquid fuel nozzle sleeve. A swirl hole is provided on the swirl sleeve that corresponds to the oil injection hole on the second swirl core.

[0006] Furthermore, the swirl channels are configured with 3 to 5 channels on the first swirl core, with a channel width of 0.2 to 0.3 mm, a channel depth of 0.2 to 0.3 mm, and a swirl radius of 1 to 1.5 mm; the swirl chamber is formed by installing the first and second swirl cores; the swirl holes are configured with 6 to 8 holes along the circumference of the swirl sleeve, with a square cross-section and a side length of 1 to 2 mm; the oil outlet holes are configured with 2 holes in each liquid fuel branch pipe, with a diameter of 1 to 2 mm; and the diameter of the injection hole is 0.5 to 0.8 mm.

[0007] Furthermore, the gaseous fuel inlet pipe and gaseous fuel branch pipe are connected to the gaseous fuel main pipe through gaseous fuel branch pipe connectors; ten gaseous fuel branch pipes are provided, and the ten gaseous fuel branch pipes and one gaseous fuel inlet pipe are evenly arranged around the gaseous fuel main pipe; gaseous fuel enters the gaseous fuel main pipe from the gaseous fuel inlet pipe, and then enters the ten circumferentially distributed gaseous fuel branch pipes evenly, and then enters the gas collection chamber through the gaseous fuel adapter, and then enters through the six circumferentially arranged swirl holes of the swirl sleeve to form a circumferential rotating airflow, which is then injected into the combustion chamber for combustion.

[0008] Furthermore, the liquid fuel inlet pipe and liquid fuel branch pipe are connected to the liquid fuel main pipe through a liquid fuel branch pipe connector; ten liquid fuel branch pipes are provided, and the ten liquid fuel branch pipes and one liquid fuel inlet pipe are evenly arranged around the circumference of the liquid fuel main pipe. Liquid fuel enters the liquid fuel main pipe from the liquid fuel inlet pipe, and then enters the ten circumferentially distributed liquid fuel branch pipes evenly. After the liquid fuel flows out from the oil outlet hole on the liquid fuel branch pipe, it flows into the swirl chamber formed by the first swirl core and the second swirl core along the circumferentially distributed swirl groove on the first swirl core. After the fuel produces circumferential flow, it is injected into the combustion chamber from the injection hole with a diameter of 0.5-0.8mm on the second swirl core for combustion.

[0009] Furthermore, the liquid fuel branch pipe and the liquid fuel nozzle sleeve are welded together under a pre-pressure of 7-8 kg to achieve a tight connection between the first swirl core and the second swirl core.

[0010] The beneficial effects of the present invention are as follows: The dual-fuel nozzle for small aero engines combines a liquid fuel line and a gaseous fuel line. During start-up and low-operation conditions, the engine uses gaseous fuel, making ignition and start-up easier. After entering idle state, the fuel is switched to liquid fuel. Therefore, neither a fuel distributor nor oxygen supplementation ignition is required. This improves the ignition performance of the small aero engine combustion chamber (including high-altitude start-up) and reduces the complexity and structural weight of the accessory piping system. Attached Figure Description

[0011] Figure 1 This is a schematic diagram of the isometric structure of the present invention; Figure 2 For the present invention Figure 1 A schematic diagram of the cross-sectional structure of a liquid fuel nozzle; Figure 3 For the present invention Figure 1 A cross-sectional schematic diagram of the gaseous fuel adapter; Figure 4 This is a schematic diagram of the swirl channel of the present invention; Figure 5 This is a schematic diagram of the vortex chamber of the present invention.

[0012] In the diagram, 1. Gaseous fuel main pipe; 11. Gaseous fuel inlet pipe; 12. Gaseous fuel branch pipe connector; 13. Gaseous fuel branch pipe; 14. Gaseous fuel adapter; 15. Outer sleeve; 16. Swirl sleeve; 17. Swirl orifice; 18. Gas collecting chamber; 2. Liquid fuel main pipe; 21. Liquid fuel inlet pipe; 22. Liquid fuel branch pipe connector; 23. Liquid fuel branch pipe; 24. Liquid fuel nozzle; 25. Liquid fuel nozzle sleeve; 26. Oil outlet; 27. First swirl core; 271. Swirl groove; 28. Second swirl core; 281. Injection hole; 29. ​​Swirl chamber. Detailed Implementation

[0013] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0014] To achieve the above objectives, the present invention provides the following specific embodiments: Figure 1 As shown, a dual-fuel nozzle for a small aircraft engine is characterized by including a gaseous fuel main pipe 1 and a liquid fuel main pipe 2. The gaseous fuel main pipe 1 is provided with a gaseous fuel inlet pipe 11 and a gaseous fuel branch pipe 13. The liquid fuel main pipe 2 is provided with a liquid fuel inlet pipe 21 and a liquid fuel branch pipe 23. A liquid fuel nozzle 24 is provided at the end of the liquid fuel branch pipe 23. The end of the gaseous fuel branch pipe 13 is connected to the liquid fuel nozzle 24 through a gaseous fuel adapter 14.

[0015] like Figure 2 and 5 As shown, the liquid fuel nozzle 24 includes a liquid fuel nozzle sleeve 25. A first swirling core 27 and a second swirling core 28 are disposed within the liquid fuel nozzle sleeve 25. The first swirling core 27 and the second swirling core 28 correspondingly form a swirling chamber 29. A swirling groove 271 is circumferentially disposed on the first swirling core 27 at the edge of the swirling chamber 29. An injection hole 281 is disposed on the second swirling core 28 at the axial position of the swirling chamber 29. The liquid fuel branch pipe 23 is connected to the liquid fuel nozzle sleeve 25 and extends into the liquid fuel nozzle. The rear end of the fuel nozzle sleeve 25 is connected to the first swirl core 27. The liquid fuel branch pipe 23 extends into the pipe wall inside the liquid fuel nozzle sleeve 25 and is provided with an oil outlet hole 26. The gaseous fuel adapter 14 includes an outer sleeve 15, inside which a swirl sleeve 16 is provided. The outer sleeve 15 is provided with a gas collecting chamber 18. The outer sleeve 15 is connected to the gaseous fuel branch pipe 13. The swirl sleeve 16 is connected to the liquid fuel nozzle sleeve 25. The swirl sleeve 16 is provided with a swirl hole 17 that corresponds to the oil injection hole 281 on the second swirl core 28.

[0016] The liquid fuel branch pipe 23 and the liquid fuel nozzle sleeve 25 are welded together under a pre-pressure of 7-8 kg to achieve a tight connection between the first swirl core 27 and the second swirl core 28.

[0017] The gaseous fuel inlet pipe 11 and gaseous fuel branch pipe 13 are connected to the gaseous fuel main pipe 1 through the gaseous fuel branch pipe connector 12. There are ten gaseous fuel branch pipes 13, and the ten gaseous fuel branch pipes and one gaseous fuel inlet pipe are evenly arranged around the gaseous fuel main pipe. The liquid fuel inlet pipe 21 and liquid fuel branch pipe 23 are connected to the liquid fuel main pipe 2 through the liquid fuel branch pipe joint 22. There are ten liquid fuel branch pipes 23, and the ten liquid fuel branch pipes and one liquid fuel inlet pipe are evenly arranged around the circumference of the liquid fuel main pipe. like Figure 4 As shown, the swirl channels 271 are configured with three channels on the first swirl core 27. The width of the swirl channels 271 is 0.2~0.3mm, the depth of the swirl channels 271 is 0.2~0.3mm, and the swirl radius is 1~1.5mm. The swirl chamber 29 is formed by installing the first swirl core 27 and the second swirl core 28, as shown. Figure 3 As shown; the swirl holes 17 are arranged in 6 to 8 positions along the circumference of the swirl sleeve, the cross-section of the swirl holes 17 is square with a side length of 1 to 2 mm, the oil outlet holes 26 are arranged in 2 positions in each liquid fuel branch pipe with a diameter of 1 to 2 mm; the diameter of the oil injection hole 281 is 0.5 to 0.8 mm. Liquid fuel enters the liquid fuel main pipe 2 from the liquid fuel inlet pipe 21, and then flows evenly into ten circumferentially distributed liquid fuel branch pipes. After flowing out from the oil outlet 26 on the liquid fuel branch pipe 23, the liquid fuel flows into the swirl chamber 29 formed by the first swirl core 27 and the second swirl core 28 along the circumferentially distributed swirl groove 271 on the first swirl core. After the fuel generates circumferential flow, it is injected into the combustion chamber for combustion from the 0.5-0.8mm diameter injection hole 281 on the second swirl core 28. Gaseous fuel enters the gaseous fuel main pipe 1 from the gaseous fuel inlet pipe 11, and then flows evenly into ten circumferentially distributed gaseous fuel branch pipes. Subsequently, it enters the gas collection chamber 18 through the gaseous fuel adapter 14, and then enters through the six circumferentially arranged swirl holes on the swirl sleeve 16, forming a circumferential rotating airflow, which is then injected into the combustion chamber for combustion.

[0018] The aforementioned dual-fuel nozzle for small aero engines uses gaseous fuel during engine start-up and low-altitude operation, making ignition and start-up easier. However, once the engine enters idle mode, it switches to liquid fuel. Therefore, it eliminates the need for a fuel distributor and oxygen supplementation ignition, thereby improving the ignition performance of the small aero engine's combustion chamber (including high-altitude start-up) and reducing the complexity and structural weight of the accessory piping system.

[0019] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A dual-fuel nozzle for a small aircraft engine, characterized in that, It includes a gaseous fuel main pipe and a liquid fuel main pipe. The gaseous fuel main pipe is provided with a gaseous fuel inlet pipe and a gaseous fuel branch pipe. The liquid fuel main pipe is provided with a liquid fuel inlet pipe and a liquid fuel branch pipe. A liquid fuel nozzle is provided at the end of the liquid fuel branch pipe. The end of the gaseous fuel branch pipe is connected to the liquid fuel nozzle through a gaseous fuel adapter.

2. A dual-fuel nozzle for a small aircraft engine as described in claim 1, characterized in that, The liquid fuel nozzle includes a liquid fuel nozzle sleeve, and a first swirling core and a second swirling core are provided inside the liquid fuel nozzle sleeve. The first swirling core and the second swirling core respectively form a swirling chamber. A swirling groove is provided on the first swirling core along the circumferential direction at the edge of the swirling chamber, and an injection hole is provided on the second swirling core at the axial position of the swirling chamber. The liquid fuel branch pipe is connected to the liquid fuel nozzle sleeve. The end of the liquid fuel branch pipe extending into the liquid fuel nozzle sleeve is connected to the first swirl core. An oil outlet hole is provided on the pipe wall of the liquid fuel branch pipe extending into the liquid fuel nozzle sleeve. The gaseous fuel adapter includes an outer sleeve with a gas collecting chamber. A swirl sleeve is provided inside the outer sleeve. The outer sleeve is connected to the gaseous fuel branch pipe, and the swirl sleeve is connected to the liquid fuel nozzle sleeve. A swirl hole is provided on the swirl sleeve that corresponds to the oil injection hole on the second swirl core.

3. A dual-fuel nozzle for a small aircraft engine as described in claim 2, characterized in that, The swirl channels are configured with 3 to 5 channels on the first swirl core, with a channel width of 0.2 to 0.3 mm, a channel depth of 0.2 to 0.3 mm, and a swirl radius of 1 to 1.5 mm. The swirl chamber is formed by installing the first and second swirl cores. The swirl holes are configured with 6 to 8 holes along the circumference of the swirl sleeve, with a square cross-section and a side length of 1 to 2 mm. The oil outlet holes are configured with 2 holes in each liquid fuel branch pipe, with a diameter of 1 to 2 mm. The diameter of the injection hole is 0.5 to 0.8 mm.

4. A dual-fuel nozzle for a small aircraft engine as described in claim 1, characterized in that, The gaseous fuel inlet pipe and gaseous fuel branch pipe are connected to the gaseous fuel main pipe through gaseous fuel branch pipe connectors; there are ten gaseous fuel branch pipes, and the ten gaseous fuel branch pipes and one gaseous fuel inlet pipe are evenly arranged around the gaseous fuel main pipe; gaseous fuel enters the gaseous fuel main pipe from the gaseous fuel inlet pipe, and then enters the ten circumferentially distributed gaseous fuel branch pipes evenly, and then enters the gas collection chamber through the gaseous fuel adapter, and then enters through the six circumferentially arranged swirl holes of the swirl sleeve to form a circumferential rotating airflow, which is then injected into the combustion chamber for combustion.

5. A dual-fuel nozzle for a small aircraft engine as described in claim 1, characterized in that, The liquid fuel inlet pipe and liquid fuel branch pipe are connected to the liquid fuel main pipe through a liquid fuel branch pipe connector. There are ten liquid fuel branch pipes, and the ten liquid fuel branch pipes and one liquid fuel inlet pipe are evenly arranged around the circumference of the liquid fuel main pipe. Liquid fuel enters the liquid fuel main pipe from the liquid fuel inlet pipe, and then enters the ten circumferentially distributed liquid fuel branch pipes evenly. After the liquid fuel flows out from the oil outlet hole on the liquid fuel branch pipe, it flows into the swirl chamber formed by the first swirl core and the second swirl core along the circumferentially distributed swirl groove on the first swirl core. After the fuel produces circumferential flow, it is injected into the combustion chamber from the injection hole with a diameter of 0.5-0.8mm on the second swirl core for combustion.

6. A dual-fuel nozzle for a small aircraft engine as described in any one of claims 1-5, characterized in that, The liquid fuel branch pipe and the liquid fuel nozzle sleeve are welded together under a pre-pressure of 7-8 kg to achieve a tight connection between the first swirl core and the second swirl core.

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