A direct-impingement rotating flow type mixing nozzle for water ramjet engine, water ramjet engine

Abstract

This invention provides a direct-injection swirl-type mixing nozzle for a water-jet engine and a water-jet engine itself, relating to the field of water-jet engine technology, to solve one of the technical problems of low nozzle flow rate, poor atomization effect, and short penetration depth in water-jet engines. The direct-injection swirl-type mixing nozzle for a water-jet engine includes a core and a cavity enclosed by a shell, the shell having opposing inlet and outlet ends; along the direction from the inlet end to the outlet end, the cavity sequentially has a first cavity section and a second cavity section, the core being disposed in the first cavity section, and the core having at least one channel for water flow. This nozzle, used in water-jet engines, can improve atomization effect while maintaining a large flow rate.

Description

Technical Field

[0001] This invention relates to the field of water jet engine technology, and more particularly to a direct-injection swirl mixing nozzle for a water jet engine and a water jet engine. Background Technology

[0002] As a high-speed underwater propulsion system, the water ramjet engine utilizes the chemical reaction between high-energy water-reactive metallic fuels rich in aluminum and magnesium and external water to generate additional thrust. The operation of a water ramjet engine typically consists of two stages: First, the fuel-rich propellant, rich in metallic fuel, burns to produce high-temperature, fuel-rich primary combustion gas; second, this primary combustion gas is injected into the combustion chamber, mixes with externally introduced atomized water droplets, and reacts to generate a large amount of high-temperature, high-pressure gas, which then expands through the nozzle to produce thrust. Therefore, nozzles need to be installed in the combustion chamber to atomize the externally introduced water, improving the mixing efficiency with the primary combustion gas and ensuring more complete combustion.

[0003] In related technologies, the atomized particle size at the outlet of the DC nozzle is large and unevenly distributed. When used in water-jet engines to mix atomized water with fuel-rich gas, it is prone to problems such as unstable combustion or even flameout. The swirl nozzle structure is more complex and larger than the DC nozzle structure, making it unsuitable for relatively small water-jet engines. Moreover, the water flow rate is low, resulting in a low water-fuel ratio in the combustion chamber of the water-jet engine. Summary of the Invention

[0004] The purpose of this invention is to provide a direct-injection swirl mixing nozzle for a water-jet engine and a water-jet engine, so as to solve one of the technical problems of low nozzle flow rate, poor atomization effect and short penetration depth in water-jet engines.

[0005] To achieve the above objectives, the present invention provides the following technical solution: In a first aspect, embodiments of the present invention provide a direct-injection swirling mixing nozzle for a water jet engine, comprising a core and a cavity enclosed by a housing, the housing having opposing inlet and outlet ends; Along the direction from the inlet end to the outlet end, the cavity has a first cavity segment and a second cavity segment in sequence, the core is disposed in the first cavity segment, and the core has at least one channel through which water flows.

[0006] According to at least one embodiment of the present invention, the cross-sectional area of ​​the second cavity gradually decreases along the direction away from the first cavity.

[0007] According to at least one embodiment of the present invention, the core is disposed at the connection position between the first cavity segment and the second cavity segment.

[0008] According to at least one embodiment of the present invention, the inner wall surface of the first cavity segment is cylindrical; and / or, The inner wall of the second cavity is conical.

[0009] According to at least one embodiment of the present invention, the outer wall surface of the core is adapted to the inner wall surface of the first cavity segment.

[0010] According to at least one embodiment of the present invention, the core and the shell are integrally formed; or, The core is detachably connected to the housing.

[0011] According to at least one embodiment of the present invention, at least one groove is formed on the outer wall surface of the core, and the groove and the shell form the channel; The centerline of the groove is a spiral.

[0012] According to at least one embodiment of the present invention, the number of channels is three, and each channel is evenly distributed along the circumference of the core.

[0013] According to at least one embodiment of the present invention, the distance between the end face of the core facing away from the second cavity segment and the inlet end is in the range of 0 to 10 mm.

[0014] In a second aspect, embodiments of the present invention provide a water-jet engine, including the direct-shot swirling mixing nozzle described in the first aspect.

[0015] In one or more technical solutions provided in the exemplary embodiments of the present invention, at least one of the following beneficial effects can be achieved.

[0016] The exemplary embodiment of the present invention provides a direct-injection swirling mixing nozzle for a water jet engine, comprising a core and a cavity enclosed by a shell, the shell having opposing inlet and outlet ends; the cavity is sequentially divided into a first cavity section and a second cavity section along the axial direction, the core is disposed in the first cavity section and its outer wall surface is adapted to the inner wall surface of the first cavity section, and by opening at least one spiral channel on the core, a stable swirling flow is formed when the water flows into the second cavity section; the inner wall surface of the second cavity section has a conical contraction structure, when the water flows through the contraction of the second cavity section under pressure, the flow velocity continuously increases and the swirling intensity is enhanced, and under the action of centrifugal force, it spreads out in the tangential direction, and the water flow forms an atomized cone effect at the outlet end.

[0017] Furthermore, a central direct-flow through-hole is provided at the central axis of the core for water flow. In other words, in addition to the spiral channel, a central direct-flow channel is also provided on the core to achieve synergistic coupling of direct flow and swirling flow. Part of the water flow directly reaches the outlet end of the nozzle through this central direct-flow through-hole, effectively compensating for the outlet flow rate. Compared with the hollow cone-shaped spray produced by the swirling nozzle in the prior art, the direct-flow swirling mixing nozzle of the present invention can form a solid and complete cone-shaped spray, so that the high-temperature fuel-rich gas flow can also fully contact and react with the water mist near the central axis, greatly improving the combustion efficiency.

[0018] Furthermore, while a simple swirling nozzle produces finer atomization compared to a direct-flow nozzle, its penetration depth is shorter, causing the atomized water to flow only near the combustion chamber wall, which is not conducive to the secondary combustion of fuel-rich gas. However, this invention, through the synergistic effect of direct jet and swirling flow, retains the fineness of swirling atomization while significantly improving the jet penetration depth, allowing the water mist to effectively cover most of the combustion chamber area, thereby improving the mixing uniformity and reaction efficiency of water mist and fuel gas.

[0019] Furthermore, in the hybrid nozzle of the present invention, the coordinated design of the three parts of the core and shell (the diameter and axial length of the first cavity corresponding to the first part, the second cavity corresponding to the second part, and the third cavity corresponding to the third part) significantly reduces its size by about an order of magnitude compared to the size of the combustion chamber nozzle of a traditional aero-engine. Through the precise matching of various components and the optimization of geometric parameters, the nozzle flow rate is increased while forming a solid cone-shaped spray with an atomization cone angle of up to 79°, which is more suitable for the small and compact combustion chamber space layout of water-rammed engines. Attached Figure Description

[0020] The accompanying drawings illustrate exemplary embodiments of the invention and, together with the description thereof, serve to explain the principles of the invention. These drawings are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification.

[0021] Figure 1 This is an isometric structural schematic diagram of a nozzle according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the exploded structure of a nozzle according to an embodiment of the present invention; Figure 3 This is an isometric structural diagram of the core according to an embodiment of the present invention; Figure 4 This is an isometric structural schematic diagram of the second part of the housing according to an embodiment of the present invention; Figure 5 This is an isometric structural schematic diagram of the third part of the housing according to an embodiment of the present invention; Figure 6These are water phase volume fraction cloud diagrams for various nozzle configurations according to embodiments of the present invention; Figure 7 This is a cloud diagram of the water phase volume fraction of nozzle configuration 8 according to an embodiment of the present invention.

[0022] Figure label: 10. Shell; 11. First part; 12. Second part; 13. Third part; 101. First cavity segment; 102. Second cavity segment; 103. Third cavity segment; 20. Core; 21. Through hole; 22. Channel. Detailed Implementation

[0023] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0024] The nozzles used in water ramjet engines operate similarly to those used in liquid rocket engines, but their working media differ. The atomizing nozzles in related technologies often fail to achieve the desired atomization effect to guarantee the water-fuel ratio in the combustion chamber of a water ramjet engine, hindering the physical mixing and chemical reaction between the fuel-rich combustion gases and the oxidizer.

[0025] Example 1 Figure 1 This is an isometric structural schematic diagram of a nozzle according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the exploded structure of a nozzle according to an embodiment of the present invention. (Combined with...) Figure 1 and Figure 2 As shown, the direct-injection swirl mixing nozzle for a water jet engine provided by an exemplary embodiment of the present invention includes a core 20 and a cavity enclosed by a housing 10, the housing 10 having opposing inlet and outlet ends; along the direction from the inlet end to the outlet end, the cavity sequentially has a first cavity section 101 and a second cavity section 102, the core 20 is disposed in the first cavity section 101, and the core 20 has at least one channel 22 for water to flow through.

[0026] The shell 10, formed by the first part 11, the second part 12, and the third part 13, encloses a cavity through which water flows. The first cavity section 101 of the cavity is cylindrical and corresponds to the first part 11 of the shell 10; the second cavity section 102 is conical and corresponds to the second part 12 of the shell 10; the third cavity section 103 is cylindrical and corresponds to the third part 13 of the shell 10. It should be noted that the end of the first cavity section 101 facing away from the second cavity section 102 is the inlet end, and the end of the third cavity section 103 facing away from the second cavity section 102 is the outlet end.

[0027] The channel 22 on the core 20 runs through the core 20 axially and is spiral in shape, so that the water flow generates a stable swirling effect when it passes through the channel 22. There can be multiple channels 22, such as three, and they are evenly distributed around the core 20.

[0028] The core 20 is disposed in the first cavity 101, and its outer wall surface is closely fitted with the inner wall surface of the first cavity 101. For example, the two can be clearance fit, interference fit, or transition fit.

[0029] Alternatively, channel 22 may be formed inside core 20.

[0030] To solve the technical problem of the difficulty in processing the channel 22 inside the core 20, a groove is opened on the outer wall of the core 20. The groove and the inner wall of the first part 11 together form the channel 22. At this time, the center line of the groove is a spiral line, so that after the water flows into the first cavity 101, it is forced to induce a high shear and strong rotation flow pattern.

[0031] Optionally, the core 20 and the shell 10 can be integrally molded.

[0032] Optionally, the core 20 and the housing 10 can also be a detachable connection structure to balance processing accuracy and subsequent maintenance requirements; preferably, the core 20 and the housing 10 are interference fit or transition fit.

[0033] Figure 4 This is an isometric structural schematic diagram of the second part of the housing according to an embodiment of the present invention; Figure 5 This is an isometric structural schematic diagram of the third part of the housing according to an embodiment of the present invention. Figure 4 and Figure 5 As shown, the cross-sectional area of ​​the second cavity 102 gradually decreases, meaning that the second cavity 102 converges along the direction from the inlet end to the outlet end, effectively accelerating the water flow and enhancing its kinetic energy. The inner diameter of the first cavity 101 is equal to the inner diameter of the larger end of the second cavity 102, and the inner diameter of the third cavity 103 is equal to the inner diameter of the smaller end of the second cavity 102. Thus, a complete water flow path is formed between the first cavity 101, the second cavity 102, and the third cavity 103, and their central axes are collinear.

[0034] It should be noted that, in order to show the structure of the first cavity 101, the second cavity 102 and the third cavity 103, the first part 11, the second part 12 and the third part 13 of the shell 10 in the relevant figures have been partially cut out.

[0035] Continue as Figure 4 and Figure 5As shown, the inner diameter of the third cavity 103 of the third part 13 is equal to the inner diameter of the small end of the second cavity 102, and the diameter of the outer wall of the third part 13 is the same as the diameter of the outer wall of the second part 12.

[0036] For example, the outer wall surface of the core 20 is also cylindrical, and its diameter is the same as the inner diameter of the first cavity segment 101.

[0037] To address the technical challenge of achieving the required precision in integrated nozzle manufacturing, the core 20, the first part 11, the second part 12, and the third part 13 of the housing 10 can be processed separately. Then, the core 20 is inserted into the first cavity 101 of the housing 10, and the second part 12 is welded to the first part 11 and the third part 13. This method helps to ensure the processing precision of each component and reduces the overall manufacturing difficulty.

[0038] The axial position of the core 20 in the first cavity 101 can be adjusted according to actual needs. Preferably, the core 20 is located at the connection between the first cavity 101 and the second cavity 102, that is, one end face of the core 20 is close to the end face of the large end of the second cavity 102, and the other end face of the core 20 maintains a distance of 0 to 10 mm from the inlet end of the nozzle, so that the water flow first forms a stable transition flow field after entering the first cavity 101, and then generates a uniform swirling flow induced by the spiral groove.

[0039] To address the technical challenges of short penetration depth and difficulty in simultaneously achieving both atomization effect and outlet flow rate in swirl nozzles, Figure 3 This is an isometric structural diagram of the core according to an embodiment of the present invention. (Combined with...) Figure 2 and Figure 3 As shown, an axially extending through hole 21 is also provided at the central axis of the core 20. This through hole 21 is independent of the spiral groove and is used to introduce the central direct jet, thereby superimposing the axial penetrating jet on the basis of swirling atomization for synergy.

[0040] In practical applications, the direct-injection swirl-type mixing nozzle for a water-jet engine provided in the exemplary embodiment of the present invention is installed in the combustion chamber of the water-jet engine. A water flow with a certain pressure enters the first chamber 101 at the inlet end of the nozzle for steady flow. After being fully developed in the first chamber 101, the water flow enters the spiral channel 22 and the through hole 21 of the central axis of the core 20. The water flow gains radial momentum and accelerates rotation in the spiral channel 22, and then enters the conical second chamber 102. Under the combined action of the spiral channel 22 and the central through hole 21, the radial and axial momentum of the water flow is fully developed in the second chamber 102, and finally it is injected into the combustion chamber through the third chamber 103.

[0041] As the water flow gains a certain radial velocity component after passing through the channel 22 with a certain helical angle, it forms a conical spray with a certain angle after being ejected from the third chamber 103 (outlet end). If only the swirling effect of the helical channel 22 is relied upon, an air core is easily formed at the center of the spray due to the pressure difference, which reduces the flow rate at the outlet end. Based on this, the through hole 21 set on the central axis of the core 20 provides an axial direct jet, which effectively fills the air core area, making the spray a solid conical structure. It can also make up for the flow loss caused by the air core, so that the conical spray at the nozzle outlet end has both a large atomization cone angle and high flow output characteristics, which significantly improves the mixing uniformity of water fuel in the combustion chamber of the water ramjet engine and improves the combustion efficiency.

[0042] Meanwhile, the nozzle of the exemplary embodiment of the present invention, through the combined control of swirling and direct jet, achieves a longer penetration depth due to the direct jet from the through hole 21 of the core 20 compared to a nozzle that simply uses the spiral channel 22. The mixed control of swirling and direct jet allows the atomized water to penetrate deeper into the core area of ​​the combustion chamber, effectively reducing wall adhesion and localized combustion richness.

[0043] Example 2 To address the technical challenge of matching the atomization cone angle of the nozzle with the outlet flow rate, this embodiment further optimizes the structural parameter matching of the direct-injection swirl mixing nozzle for water-jet engines, building upon Example 1.

[0044] In the structural parameters of the nozzle in the exemplary embodiment of the present invention, the core 20 has three spiral channels 22, and the end face of the core 20 facing the inlet end is defined as the upper end face.

[0045] The diameter of the first cavity 101 is 5mm to 15mm, for example, it can be 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, 14mm, 15mm or within any two of the above values.

[0046] The axial length of the core 20 is 0.5mm to 8mm, for example, it can be 0.5mm, 1.5mm, 2.5mm, 3.5mm, 4.5mm, 5.5mm, 6.5mm, 7.5mm or within any two of the above values. It can be understood that the axial length of the core 20 is less than or equal to the axial length of the first cavity segment 101.

[0047] The diameter of the through hole 21 at the center of the core 20 is 0mm to 1mm, for example, it can be 0.1mm, 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, or within any two of the above values.

[0048] The spiral angle of the spiral channel 22 of the core 20 is 15° to 75°, for example, it can be 15°, 20°, 25°, 30°, 35°, 40°, 45°, 50°, 55°, 60°, 65°, 70°, 75° or within any two of the above values.

[0049] The distance between the upper end face of the core 20 and the inlet end of the nozzle is 0mm to 10mm, for example, it can be 1mm, 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm or within any two of the above values.

[0050] The axial length of the third cavity 103 is 0mm to 4mm, for example, it can be 0mm, 0.2mm, 0.4mm, 0.6mm, 0.8mm, 1mm, 1.2mm, 1.4mm, 1.6mm, 1.8mm, 2mm, 2.2mm, 2.4mm, 2.6mm, 2.8mm, 3mm, 3.2mm, 3.4mm, 3.6mm, 3.8mm, 4mm or any two of the above values.

[0051] The diameter of the third cavity 103 is 0.1mm to 2mm, for example, it can be 0.1mm, 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, 1.6mm, 1.7mm, 1.8mm, 1.9mm, 2mm or within any two of the above values.

[0052] The cone angle of the second cavity 102 is 30° to 75°, for example, it can be 30°, 35°, 40°, 45°, 50°, 55°, 60°, 65°, 70°, 75° or within any two of the above values.

[0053] Table 1 lists the structural parameters of nine nozzle configurations according to exemplary embodiments of the present invention. Unless otherwise specified, the diameters of the first cavity section 101 and the core 20 of the nozzle are 10 mm, the cone angle of the second cavity section 102 is 60°, the diameter of the third cavity section 103 is 1 mm, the outer diameter of the third part 13 is 3 mm, and the axial length of the core 20 is 3 mm.

[0054] Table 1 Structural parameters of various nozzle configurations

[0055] Figure 6 These are water phase volume fraction cloud diagrams for various nozzle configurations according to embodiments of the present invention; Figure 7This is a cloud diagram of the water phase volume fraction of nozzle configuration 8 according to an embodiment of the present invention. Figure 6 and Figure 7 As shown, in the nozzle of configuration 9, the core 20 does not have a through hole 21 at the central axis, similar to a traditional swirl nozzle. Analysis of the water phase volume fraction cloud diagrams of the nozzles of each configuration shows that, except for configurations 8 and 9, the nozzles of configurations 1 to 7 do not form a significant atomization cone angle, that is, the atomization effect is poor.

[0056] The nozzle of configuration 8 forms a distinct atomization cone angle and has no air core at the central axis of the nozzle, that is, the nozzle of configuration 8 forms a solid atomization cone angle and the atomized particle size is reduced; while the nozzle of configuration 9 forms an atomization cone angle but also forms an air core at the central axis of the nozzle, that is, the nozzle of configuration 9 forms a hollow atomization cone angle.

[0057] The present invention also simulates and calculates the outlet flow rate of nozzles of various configurations, and the calculation results are shown in Table 2.

[0058] Table 2. Outlet flow rates of various nozzle configurations

[0059] Referring to Table 2, among the nozzle configurations, the nozzle of configuration 8 has the optimal structural parameters. Its core 20 has three spiral channels 22 and a central through hole 21. The synergistic effect of the spiral channels 22 and the through hole 21 makes the atomization cone angle of this nozzle configuration reach 79°. At the same time, since part of the water flow at the inlet end reaches the outlet end of the nozzle through the through hole 21, the flow rate at the outlet end of the nozzle is compensated, and the outlet flow rate is 34 g / s. In contrast, configuration 9, which does not have a central through hole 21 in its core 20, does not have effective compensation for the flow rate at the outlet end, and the outlet flow rate is 25.7 g / s. Moreover, its atomization cone angle is only 53°, which is much smaller than the atomization cone angle of 79° of configuration 8.

[0060] To achieve a large outlet flow rate in the nozzle, the diameter of the through-hole 21 in the core 20 needs to be relatively large. However, a large through-hole 21 diameter will affect the formation of the atomization cone angle; a small through-hole 21 diameter will not meet the compensation requirements for the outlet flow rate. Based on this, to solve the balance problem between the nozzle's outlet flow rate and atomization cone angle, when the diameter of the through-hole 21 in the core 20 of the nozzle configuration 8 is 0.3 mm, it not only achieves a large outlet flow rate but also a large atomization cone angle, and produces a solid cone spray, which can meet the requirements of the water-jet engine for both atomization cone angle and outlet flow rate.

[0061] Example 3 The present invention also provides a water-jet engine, including the direct-shot swirling mixing nozzle described in Embodiment 1 or Embodiment 2.

[0062] The technical advantages of the aforementioned water jet engine over existing technologies are the same as those of the aforementioned direct-injection swirl mixing nozzle, and will not be repeated here.

[0063] Those skilled in the art should understand that the above embodiments are merely for illustrating the present invention and are not intended to limit the scope of the invention. Those skilled in the art can make other changes or modifications based on the above disclosure, and these changes or modifications still fall within the scope of the present invention.

Claims

1. A direct-injection swirl-type mixing nozzle for a water-jet engine, characterized in that, It includes a core and a cavity enclosed by a shell, the shell having opposing inlet and outlet ends; Along the direction from the inlet end to the outlet end, the cavity has a first cavity segment and a second cavity segment in sequence, the core is disposed in the first cavity segment, and the core has at least one channel through which water flows.

2. The direct-flow swirling mixing nozzle according to claim 1, characterized in that, Along the direction away from the first cavity segment, the cross-sectional area of ​​the second cavity segment gradually decreases.

3. The direct-flow swirling mixing nozzle according to claim 2, characterized in that, The core is located at the connection point between the first cavity segment and the second cavity segment.

4. The direct-flow swirling mixing nozzle according to claim 3, characterized in that, The inner wall of the first cavity is cylindrical; and / or, The inner wall of the second cavity is conical.

5. The direct-flow swirling mixing nozzle according to claim 4, characterized in that, The outer wall surface of the core is adapted to the inner wall surface of the first cavity segment.

6. The direct-flow swirling mixing nozzle according to claim 5, characterized in that, The core and the shell are integrally formed.

7. The direct-flow swirling mixing nozzle according to claim 5, characterized in that, The core is detachably connected to the housing.

8. The direct-flow swirling mixing nozzle according to any one of claims 1-7, characterized in that, The number of channels is three, and each channel is evenly distributed along the circumference of the core.

9. The direct-flow swirling mixing nozzle according to claim 8, characterized in that, The distance between the end face of the core facing away from the second cavity segment and the inlet end ranges from 0 to 10 mm.

10. A water-jet engine, characterized in that, Includes the direct-flow swirling mixing nozzle as described in any one of claims 1-9.

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