Rotational flow atomizing nozzle

Abstract

The invention discloses a rotational flow atomizing nozzle, which belongs to the technical field of atomizing structures of combustion chambers of gas turbine engines and comprises a hub structure, a first swirler, a nozzle structure, a resonance component and a connecting rod component. A hub structure serves as a carrier, a generator structure comprising a nozzle structure and a resonance component is arranged in the hub structure, an air inlet and a fuel oil inlet are formed in the nozzle structure, an annular cavity for forming supersonic speed air is formed behind the air inlet, and at a nozzle outlet, the fuel oil is subjected to primary atomization under the action of supersonic speed airflow shearing force; meanwhile, based on the effect of the resonance component, a resonance cavity can be formed between the nozzle and the resonance component, so that secondary atomization of fuel oil is achieved, and combination of the ultrasonic atomization technology and the swirler is achieved.

Description

Technical Field

[0001] This application belongs to the technical field of atomization structures for gas turbine engine combustors, and particularly relates to a swirl atomizing nozzle. Background Technique

[0002] With the continuous development of high-performance aero-engines, the industry has put forward higher requirements for fuel atomization technology, specifically as follows: complete combustion within a shorter combustion zone to shorten the length of the combustor and reduce its weight; better organize the concentration field in the main combustion zone because of the shortage of gas volume for adjusting the outlet temperature field in high-temperature-rise combustors; high requirements for ignition performance and lean blowout range; low pollutant emissions to meet the requirements of future low-pollution emissions for aero-gas turbines. At the same time, with the continuous increase of the pressure ratio and temperature rise of aero-engine combustors, some problems have emerged in the use of centrifugal nozzles. For example, the spray cone angle becomes smaller under high pressure, affecting the fuel distribution in the main combustion zone, increasing smoke and flame radiation, and also deteriorating the quality of the combustor outlet temperature field. In contrast, the swirl cup air atomizing nozzle can ensure full and uniform mixing of fuel and air flow, and has advantages such as low fuel supply pressure and insensitivity of the outlet temperature field to fuel changes, thus replacing the centrifugal nozzle in higher-performance engines.

[0003] In the prior art, although the three-stage axial swirler can enhance turbulent mixing through multi-stage swirling, the synergistic effect between its tangential hole stage and the nozzle has not been fully explored. In addition, although the hydrodynamic ultrasonic atomization technology does not require external energy, the design of its adaptability with the multi-stage swirler is still blank.

[0004] Application Content The purpose of this application is to provide a swirl atomizing nozzle to solve the problems existing in the prior fuel atomization mentioned in the above background technique.

[0005] To achieve the above purpose, this application provides the following technical solution: A swirl atomizing nozzle, comprising: A hub structure, including a first hub portion and a second hub portion arranged radially outside the first hub portion, and a first swirl interval is defined between the first hub portion and the second hub portion; A first swirler, arranged within the first swirl interval and including a plurality of first swirl vanes uniformly arranged in the circumferential direction; A nozzle structure, including a central tube body and a nozzle member arranged radially outside the central tube body. A fuel passage extending along the axis O is defined within the central tube body. The nozzle member is installed on the inner wall surface of the first hub portion. A gas passage is defined between the nozzle member and the central tube body, and the cross-sectional area of the outlet section of the gas passage gradually decreases along the gas flow direction; A resonance member, spaced apart from the nozzle structure in the axial direction; The connecting rod member, one end of the connecting rod member is connected to the resonance member, and the other end extends into the fuel passage.

[0006] Furthermore, the blade inclination angle of the first swirler blade is 45° - 50°, and the thickness is 1.2 mm - 1.8 mm.

[0007] Furthermore, a resonance cavity is defined between the resonance member and the outlet of the nozzle structure, and the ratio of the length of the resonance cavity to the cross-sectional diameter of the outlet section of the gas passage is 1 - 1.5.

[0008] Furthermore, the fuel passage includes a first section and a second section arranged in sequence along the fuel flow direction, and the cross-sectional area of the second section is larger than the cross-sectional area of the first section and the cross-sectional area of the connecting rod member.

[0009] Furthermore, the downstream section of the second hub portion is a Venturi tube structure.

[0010] Furthermore, the hub structure further includes a third hub portion arranged radially outside the second hub portion. A second swirl interval for accommodating the second swirler is defined between the third hub portion and the second hub portion, and in the axial direction, the outlet of the second swirl interval is located on the downstream side of the first swirl interval.

[0011] Furthermore, the second swirler includes a plurality of second swirl blades uniformly arranged in the circumferential direction. The blade inclination angle of the second swirl blade is 40° - 50°, and the thickness is 1.2 mm - 1.8 mm.

[0012] Furthermore, the hub structure further includes an outer hub portion arranged radially outside the third hub portion. The outer hub portion is connected to the third hub portion through an annular flange, and a third swirl interval is defined between the third hub portion and the outer hub portion. In the axial direction, the third swirl interval is located on the downstream side of the second swirl interval.

[0013] Furthermore, a plurality of obliquely cut holes are uniformly arranged on the outer hub portion in the circumferential direction, and the axis of a single obliquely cut hole is arranged at an angle to the axis O.

[0014] Furthermore, the angle between the axis of the obliquely cut hole and the axis is 28° - 32°.

[0015] Compared with the prior art, the beneficial effects of the present application are: In this application, with the hub structure as the carrier, a generator structure including a nozzle structure and a resonance member is arranged inside the hub structure. The position of the nozzle structure is provided with inlets for air and fuel. After the air inlet, there is an annular cavity for forming supersonic air. At the nozzle outlet, the fuel is atomized once under the action of the shear force of the supersonic air flow. At the same time, based on the action of the resonance member, a resonance cavity can be formed between the nozzle and the resonance member to achieve secondary atomization of the fuel, realizing the combination of ultrasonic atomization technology and a swirler. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a sectional perspective view of the atomizing nozzle of this application; Figure 2 It is a sectional schematic view of the atomizing nozzle of this application Figure 1 ; Figure 3 It is a sectional schematic view of the atomizing nozzle of this application Figure 2 。

[0017] In the figure: 100, the first hub part; 101, the second hub part; 102, the third hub part; 103, the annular flange; 104, the outer hub part; 200, the first swirler vane; 201, the second swirler vane; 202, the chamfered hole; 300, the central pipe body; 301, the fuel passage; 301a, the first section; 301b, the second section; 302, the nozzle member; 303, the gas passage; 303a, the inlet section; 303b, the outlet section; 304, the connecting rod member; 305, the resonance member; 305a, the side wall part; 305b, the end face part; 306, the resonance cavity. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0018] Next, the technical solutions in the embodiments of this application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of this application. Obviously, the described embodiments are only a part of the embodiments of this application, rather than all the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of this application.

[0019] A swirler atomizing nozzle, the main body of which is composed of a hub structure, a swirler structure and a generator structure. Among them, the hub structure extends along the axis O and is configured as the installation carrier of the swirler structure. An atomizing interval for accommodating the generator structure is defined inside the hub structure. After fuel and gas flow in through the inlet end of the atomizing nozzle, under the action of the swirler structure and the generator structure, the fuel is atomized and flows out from the outlet end. For the convenience of description, the axial positions of the parts of the atomizing nozzle are described based on the gas flow direction. Exemplarily, refer to Figure 2, in the figure, the arrow X indicates the flow direction of the gas in the axial direction. Correspondingly, the subsequent resonance member 305 is located on the downstream side of the central tube 300 of the nozzle structure in the axial direction.

[0020] In some embodiments, referring to Figure 1 , the above-mentioned hub structure includes a first hub portion 100, a second hub portion 101, and a third hub portion 102. The first hub portion 100, the second hub portion 101, and the third hub portion 102 are all substantially cylindrical members extending along the axis O. And the second hub portion 101 is located between the first hub and the third hub portion 102 in the radial direction, that is, the first hub portion 100, the second hub portion 101, and the third hub portion 102 are arranged in order from inside to outside in the radial direction, and a first swirling interval in an annular shape is defined between the first hub portion 100 and the second hub portion 101. A second swirling interval in an annular shape is defined between the third hub portion 102 and the second hub portion 101, and the outlet of the second swirling interval is located on the downstream side of the outlet of the first swirling interval in the axial direction, that is, the axial length of the second hub portion 101 is greater than the axial length of the first hub portion 100 and less than the axial length of the third hub portion 102.

[0021] Continue to refer to Figure 1 , and in combination with Figure 2 , the above-mentioned hub structure further includes an outer hub portion 104 provided on the radially outer side of the third hub portion 102. The outer hub portion 104 is fixed to the outer wall surface of the third hub portion 102 through an annular flange 103, and a third swirling interval in an annular shape is defined between the outer hub portion 104 and the third hub portion 102. And in the axial direction, the above-mentioned third swirling interval is located on the downstream side of the second swirling interval, that is, the outlets of the first swirling interval, the second swirling interval, and the third swirling interval are arranged in order in the axial direction along the gas flow direction. Based on the design of the positions of the first swirling interval, the second swirling interval, and the third swirling interval in the axial direction, the step-by-step atomization of the fuel can be achieved.

[0022] In some embodiments, the cross-sectional area of the above-mentioned third hub portion 102 gradually decreases along the first direction, so that the swirling gas output from the first swirling interval and the second swirling interval converges toward the axis O while flowing in the axial direction to achieve contact with the gas in the subsequent fuel passage 301, thereby realizing the atomization of the fuel. In some embodiments, the outlet side portion of the above-mentioned second hub portion 101 is configured as a Venturi tube structure.

[0023] Refer to Figure 2, the above cyclone structure includes a first cyclone, a second cyclone, and a third cyclone. In some embodiments, both the first cyclone and the second cyclone are radial cyclones. The first cyclone is disposed within a first swirling region, and the second cyclone is disposed within a second region. Meanwhile, the second cyclone is located below the first cyclone in the axial direction, that is, the first cyclone and the second cyclone are spaced apart in the axial direction. Exemplarily, the axial spacing between the first cyclone and the second cyclone (i.e., the subsequent axial spacing between the first swirling blade 200 and the second swirling blade 201) is 0.2 to 0.4 times the diameter of the cyclone structure. Correspondingly, the above third cyclone is an inclined cut hole 202 cyclone.

[0024] In some embodiments, referring to Figure 2 , the above first cyclone includes a plurality of first swirling blades 200 uniformly arranged in the circumferential direction. A single first swirling blade 200 extends obliquely in the axial direction, and the root of the first swirling blade 200 is fixed to the outer wall surface of the first hub portion 100 by brazing or 3D printing. In some examples, the blade inclination angle of the first swirling blade 200 is 45 to 50°, the thickness is 1.2 to 1.8 mm, and the width is 3.3 mm.

[0025] In some embodiments, the above second cyclone includes a plurality of second swirling blades 201 uniformly arranged in the circumferential direction. Specifically, a single second swirling blade 201 extends obliquely in the axial direction. Exemplarily, the blade inclination angle of the above second swirling blade 201 is 40 to 50°, the thickness is 1.2 to 1.8 mm, and the width is 2 mm. Moreover, the inclination directions of the first swirling blade 200 and the second swirling blade 201 are opposite, and the stagger angle between the first swirling blade 200 and the second swirling blade 201 is 15° to 25°, that is, the swirling directions of the first cyclone and the second cyclone are opposite to form a reverse shear flow field. Exemplarily, from the gas inflow direction, the above first swirling blade 200 is a swirling blade with a clockwise swirling direction, and correspondingly, the second swirling blade 201 is a swirling blade with a counterclockwise swirling direction.

[0026] In some embodiments, the above third cyclone is composed of a plurality of inclined cut holes 202 formed on the outer hub portion 104, and the plurality of inclined cut holes 202 are uniformly arranged in the circumferential direction. In some embodiments, the angle between the axis of the above inclined cut hole 202 and the axis O is 28° to 32°. In some examples, the ratio of the length to the aperture of the above inclined cut hole 202 is 3 to 5. Exemplarily, the aperture of the inclined cut hole 202 is 2 mm, and the hole length is 6 mm. In some embodiments, a 45° chamfer is provided at the outlet end of the above inclined cut hole 202 to optimize the flow separation.

[0027] In some embodiments, referring to Figure 2 , and in combination with Figure 3, The above generator structure includes a nozzle structure and a resonance member 305. The nozzle structure includes a central tube body 300 extending along the axis O and a nozzle tube member 302. The nozzle tube member 302 is located radially outside the central tube body 300 and is connected to the first hub portion 100, and a gas passage 303 is defined corresponding between the central tube body 300 and the nozzle tube member 302. In some embodiments, the above gas passage 303 includes an inlet section 303a and an outlet section 303b arranged in sequence along the first direction. The cross-sectional area of the outlet section 303b gradually decreases along the gas flow direction. Exemplarily, the diameter of the above outlet section 303b is 8-12 mm, that is, the maximum diameter of the outlet section 303b is 12 mm and the minimum diameter is 8 mm. In some examples, the included angle between the inner wall profile of the nozzle tube member 302 in the outlet section 303b and the axis O is 24°.

[0028] Continue to refer to Figure 3 , A fuel passage 301 extending along the axis O is defined in the above central tube body 300. In some embodiments, the above fuel passage 301 includes a first section 301a and a second section 301b arranged in sequence along the gas flow direction. The cross-sectional area of the second section 301b is larger than that of the first section 301a to cooperate with the subsequent pull rod member to form an annular gap.

[0029] Refer to Figure 3 , The above generator structure further includes a pull rod member extending along the axis O. One end of the pull rod member is connected to the resonance member 305, and the other end extends into the second section 301b of the fuel passage 301. The cross-sectional area of the second section 301b is larger than that of the pull rod member to form an annular gap between the inner wall surface of the central tube body 300 and the outer wall surface of the pull rod member.

[0030] Refer to Figure 3 , The above resonance member 305 is spaced from the nozzle structure in the axial direction, and a resonance cavity 306 is defined corresponding between the resonance member 305 and the outlet of the nozzle structure ( Figure 3 the interval defined by the dashed square in the figure). The axial distance between the resonance cavity 306 and the primary atomization outlet (i.e., the outlet of the nozzle structure) is 4 mm, which is used to reflect sound waves to form a standing wave, trigger strong ultrasonic vibration, and realize secondary atomization. The relationship between the length L (not marked in the figure) of the resonance cavity 306 and the diameter D (not marked in the figure) of the outlet section 303b of the nozzle tube member 302 satisfies L / D = 1-1.5, that is, the ratio of the maximum value of the length L of the resonance cavity 306 and the diameter D of the outlet section 303b of the nozzle tube member 302 and the ratio of the minimum value of the length L of the resonance cavity 306 and the diameter D of the outlet section 303b of the nozzle tube member 302 are both in the range of 1-1.5, and the ratio of the cavity volume to the cross-sectional area is 3-8 mm to ensure the stability of the cavitation frequency.

[0031] Specifically, the above resonance member 305 includes an end face portion 305b and a side wall portion 305a formed by the end face portion 305b extending in the axial direction, wherein the inner wall surface diameter of the side wall portion 305a is 8 mm and the outer wall surface diameter is 8.3 mm.

[0032] The assembly and working process of the atomizing nozzle of the present application are as follows: First, a swirler structure is machined from a nickel-based superalloy. The first swirler consists of 12 swirler vanes with a clockwise swirl direction, the vane inclination angle is 50°, the thickness is 1.5 mm, the width is 3.3 mm, and it is fixed to the hub structure through a brazing process at 950 °C - 1000 °C or a 3D printing process; the second swirler consists of 12 vanes with a counterclockwise swirl direction, the inclination angle is 45°, the thickness is 1.5 mm, the width is 2 mm, and the axial distance from the first swirler vane 200 is 0.3 times the diameter of the swirler structure, forming a reverse shear flow field; the third swirler is 12 obliquely cut holes 202 evenly distributed circumferentially, with a hole diameter of 2 mm and a hole length of 6 mm (L / D = 3), the axis of the obliquely cut hole 202 forms an angle of 30° with the axial direction of the swirler, and a 45° chamfer is provided at the outlet end to optimize the flow separation. In the generator structure, the divergence angle of the outlet section 303b of the nozzle member 302 is 24°. After fuel and air enter through the inlets respectively, primary atomization (average particle size SMD ≈ 25 μm) is completed by a supersonic airflow (Mach number Ma = 1.2 - 1.5); the resonance cavity 306 has a length of 12 mm and a volume of 60 mm³. The resonance member 305 is connected to the nozzle structure through a connecting rod member 304 to reflect sound waves to form a 20 kHz standing wave, causing the liquid droplets to be secondarily broken to an average particle size SMD ≤ 15 μm. The swirler structure and the nozzle as a whole adopt a conical-thread composite sealing structure, the surface roughness of the sealing surface Ra ≤ 0.8 μm, and a high-temperature aluminum phosphate-based sealing adhesive (thickness 0.2 mm) is filled. Tests show that at a fuel supply pressure of 4 MPa, the atomization uniformity index Dv90 / Dv10 = 1.6, the flow resistance coefficient is 0.32 (the total pressure loss is reduced by 28%), the nitrogen oxide and soot emissions are reduced by 23% and 18% respectively, the carbon deposition amount is 0.4 mg / cm² after continuous operation for 100 hours at 800 °C, and the performance decay rate < 3%. By adjusting the length of the resonance cavity 306 or the inclination angle of the obliquely cut hole 202, different working conditions can be adapted, and a pressure sensor can also be integrated to achieve dynamic regulation of the cavitation frequency.

[0033] Although the embodiments of the present application have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principle and spirit of the present application. The scope of the present application is defined by the appended claims and their equivalents.

Claims

1. A swirl atomizing nozzle, characterized in that, Comprising: A hub structure, including a first hub portion (100) and a second hub portion (101) disposed radially outside the first hub portion (100), a first swirl interval being defined between the first hub portion (100) and the second hub portion (101); A first swirler, disposed within the first swirl interval and including a plurality of first swirl vanes (200) uniformly arranged in the circumferential direction; A nozzle structure, including a central pipe body (300) and a nozzle member (302) disposed radially outside the central pipe body (300), a fuel passage (301) extending along the axis O being defined within the central pipe body (300), the nozzle member (302) being installed on the inner wall surface of the first hub portion (100), a gas passage (303) being defined between the nozzle member (302) and the central pipe body (300), and the cross-sectional area of the outlet section (303b) of the gas passage (303) gradually decreasing along the gas flow direction; A resonance member (305), spaced apart from the nozzle structure in the axial direction; A connecting rod member (304), one end of the connecting rod member (304) being connected to the resonance member (305) and the other end extending into the fuel passage (301).

2. The swirl atomizing nozzle according to claim 1, wherein: The blade inclination angle of the first swirl vanes (200) is 45° to 50°, and the thickness is 1.2 mm to 1.8 mm.

3. The swirl atomizing nozzle according to claim 1, characterized in that: A resonance cavity (306) is defined between the resonance member (305) and the outlet of the nozzle structure, and the ratio of the length of the resonance cavity (306) to the cross-sectional diameter of the outlet section (303b) of the gas passage (303) is 1 to 1.

5.

4. The swirl atomizing nozzle according to claim 1, characterized in that: The fuel passage (301) includes a first section (301a) and a second section (301b) sequentially arranged along the fuel flow direction, and the cross-sectional area of the second section (301b) is larger than the cross-sectional area of the first section (301a) and the cross-sectional area of the connecting rod member (304).

5. The swirl atomizing nozzle according to claim 1, wherein: The downstream side section of the second hub portion (101) is a venturi tube structure.

6. The swirl atomizing nozzle according to claim 1, characterized in that: The hub structure further includes a third hub portion (102) disposed radially outside the second hub portion (101), a second swirl interval for accommodating a second swirler being defined between the third hub portion (102) and the second hub portion (101), and in the axial direction, the outlet of the second swirl interval is located on the downstream side of the first swirl interval.

7. The swirl atomizing nozzle according to claim 6, characterized in that: The second swirler includes a plurality of second swirl vanes (201) uniformly arranged in the circumferential direction, the blade inclination angle of the second swirl vanes (201) being 40° to 50°, and the thickness being 1.2 mm to 1.8 mm.

8. The swirl atomizing nozzle according to claim 6, characterized in that: The hub structure further includes an outer hub portion (104) disposed radially outside the third hub portion (102), the outer hub portion (104) being connected to the third hub portion (102) through an annular flange (103), and a third swirl interval being defined between the third hub portion (102) and the outer hub portion (104), and in the axial direction, the third swirl interval is located on the downstream side of the second swirl interval.

9. The swirl atomizing nozzle according to claim 8, characterized in that: A plurality of chamfered holes (202) are uniformly arranged on the outer hub portion (104) in the circumferential direction, and the axis of a single chamfered hole (202) is arranged at an angle to the axis O.

10. A swirl atomizing nozzle according to claim 9, characterized in that: The angle between the axis of the chamfered hole (202) and the axis is 28° to 32°.

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