Injector and thrust chamber

Abstract

The application discloses a kind of injector and thrust chamber, it is related to liquid rocket engine technical field to solve the problem of poor cooling performance of gel propellant on combustion chamber wall surface.The injector includes injector body, and the injection surface of the end of the injector body close to the combustion chamber is provided with at least three inclined holes and multiple pairs of main injection holes, the inclined holes are arranged around the main injection holes, there is an axial angle β between the axial direction of the inclined hole and the axial direction of the injector body, and there is a tangential angle α between the projection line on the injection surface and the radial direction of the injection surface, the inclined hole is used to obliquely self-rotating injection of coolant into the inner wall of the combustion chamber.After injecting gel propellant into the injector body, part of the gel propellant is obliquely injected into the inner wall of the combustion chamber as coolant to form a self-rotating liquid film, improving the uniformity of the coolant covering on the wall surface of the combustion chamber and improving the cooling performance.

Description

Technical Field

[0001] This invention relates to the field of liquid rocket engine technology, specifically to an injector and thrust chamber. Background Technology

[0002] Gel propellants are high-viscosity, non-Newtonian fluid propellants formed by the self-assembly of a gelling agent into a three-dimensional mesh structure with a certain strength, encapsulating the parent liquid propellant. In storage environments, this type of propellant exhibits advantages such as leak-proof operation with minimal gaps and low volatility, resulting in good safety and maintainability. Attitude control thrust chambers using gel propellants can operate flexibly, either continuously pulsed or in a steady-state random state, similar to those using liquid propellants. Due to their combination of operational flexibility and excellent storage and maintainability, gel propellant thrust chambers have broad application prospects in the aerospace field.

[0003] The combustion gas temperature in the central region of the gel-propellant dual-element attitude control thrust chamber reaches over 3000℃. Therefore, the cooling design of the combustion chamber walls is crucial for the reliable operation of the gel-propellant dual-element attitude control thrust chamber. However, because gel propellants contain gelling agents, they have poor fluidity and high viscosity. When used as a coolant, the spread and development of the liquid film after being sprayed onto the combustion chamber walls is not as ideal as with liquid propellants, and the cooling performance obtained under the same conditions is also inferior to that of liquid propellants.

[0004] In high-pressure gel-propellant dual-element attitude control thrust chambers, the propellant combustion is most complete and the combustion temperature is high in the throat of the combustion chamber. It also has a small flow area, the highest heat flux density, and strong convective heat transfer with the wall, making it difficult to cool the throat using gel propellant. Furthermore, the high-temperature gas recirculation in the downstream recirculation zone of the high-pressure thrust chamber injection surface is strong, resulting in significant heat transfer between the high-temperature recirculation zone and the cylindrical wall of the combustion chamber. This leads to a prominent issue of high temperature at the head and body weld joints. If the cooling structure is inadequate, this can result in excessively high temperatures at the head and body weld joints, low reliability margins at these weld joints, and even weld ablation. Therefore, the cooling effect at the throat and head and body weld joints is poor in high-pressure gel-propellant dual-element attitude control thrust chambers. Summary of the Invention

[0005] The purpose of this invention is to provide an injector and thrust chamber for improving the cooling effect of gel propellant on the combustion chamber wall and throat.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] In a first aspect, the present invention provides an injector including an injector body, wherein the injector body has at least three oblique holes and multiple pairs of main injector holes on the injection surface near the combustion chamber side, the oblique holes are arranged around the main injector holes, there is an axial angle β between the axial direction of the oblique holes and the axial direction of the injector body, and there is a tangential angle α between the projection line of the axial direction of the oblique holes on the injection surface and the radial direction of the injection surface, the oblique holes being used to obliquely spin-spray gel propellant to the inner wall of the combustion chamber.

[0008] Optionally, in the above-mentioned injector, the length-to-diameter ratio of the oblique orifice is 3 to 8.

[0009] Optionally, in the above-mentioned injector, the tangential angle α is: 40°≤α≤70°.

[0010] Optionally, in the above-mentioned injector, the axial angle β is: 10°≤β≤40°.

[0011] Optionally, in the above-mentioned injector, the oblique holes and the main injection holes are staggered in the circumferential direction.

[0012] Optionally, in the above-mentioned injector, the number of oblique holes is equal to the number of main injection holes.

[0013] Optionally, in the above-mentioned injector, each oblique hole is provided with an enlarged hole structure. The connecting surface of the enlarged hole structure and the oblique hole is perpendicular to the axis of the oblique hole, and the connecting surface is located at the end of the injector body near the combustion chamber. The diameter D of the connecting surface is greater than the diameter d of the oblique hole.

[0014] Optionally, in the above-mentioned injector, the enlarged hole structure is arranged coaxially with the inclined hole.

[0015] Optionally, in the above-mentioned injector, the machining range of the diameter D of the connecting surface is: 3d≤D≤5d.

[0016] In a second aspect, the present invention also provides a thrust chamber, comprising a head, a body, and an injector, characterized in that the injector is any of the injectors described above, the injector is used to connect gel fuel and oxidant, and one end of the injector near the body is connected to the combustion chamber.

[0017] Compared with the prior art, when adopting the above technical solution, the gel propellant includes a gel oxidizer and a gel fuel. After the gel oxidizer and gel fuel are injected into the injector body respectively, part of the gel fuel and gel oxidizer flow from the injector to the main injection hole, are sprayed into the combustion chamber relative to each other and mix and burn, and part of the gel fuel flows as coolant to the inclined hole. Through the inclined hole with a certain tangential angle α and axial angle β on the injector, the coolant has axial velocity and tangential velocity when it is sprayed from the inclined hole to the inner wall of the combustion chamber. It impacts the wall of the combustion chamber obliquely from the inclined hole and forms a spin-type liquid film closely adhering to the inner wall of the combustion chamber. The oblique jet direction of the inclined hole increases the degree of circumferential spread of the coolant after impacting the wall and the circumferential uniformity of the coverage of the combustion chamber wall. It also reduces the contact between the gel fuel as coolant and the gel oxidizer when it is sprayed out of the inclined hole, increases the distribution of coolant near the impact point, improves the uniformity of coolant coverage on the wall, and improves the cooling performance. Attached Figure Description

[0018] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this invention, illustrate exemplary embodiments of the invention and are used to explain the invention, but do not constitute an undue limitation of the invention. In the drawings:

[0019] Figure 1 This is a front view of an injector and thrust chamber according to an embodiment of the present invention;

[0020] Figure 2 This is a side view of an injector and thrust chamber according to an embodiment of the present invention;

[0021] Figure 3 This is a front view of the injection surface on an injector according to an embodiment of the present invention;

[0022] Figure 4 for Figure 3 A sectional view along the upper AA direction;

[0023] Figure 5 for Figure 4 Enlarged view of a section of the inclined hole;

[0024] Figure 6 This is a layout diagram of the oblique hole and main injection hole of an injector in an embodiment of the present invention;

[0025] Figure 7 For Figure 6 Radial sectional view;

[0026] Figure 8 for Figure 4 A magnified view.

[0027] Figure label:

[0028] 1-Injector; 101-Injection surface; 102-Outer ring groove; 103-Inner ring groove; 2-Inclined hole; 201-Expanded hole structure; 3-Main injection hole; 4-Combustion chamber; 5-Gel propellant; 501-Gel fuel; 502-Gel oxidant; 6-Connecting surface; 7-Jet direction. Detailed Implementation

[0029] To make the technical problems to be solved, the technical solutions, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0030] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0031] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified. "Several" means one or more, unless otherwise explicitly specified.

[0032] In the description of this invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", 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 invention 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 invention.

[0033] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0034] like Figures 1-8As shown, an injector 1 provided in an embodiment of the present invention includes an injector 1 body. The injection surface 101 of the injector 1 body near the combustion chamber 4 is provided with at least three oblique holes 2 and multiple pairs of main injection holes 3. The oblique holes 2 are arranged around the main injection holes 3. There is an axial angle β between the axial direction of the oblique holes 2 and the axial direction of the injector 1 body, and there is a tangential angle α between the projection line of the axial direction of the oblique holes 2 on the injection surface 101 and the radial direction of the injection surface 101. The oblique holes 2 are used to obliquely spin-spray coolant onto the inner wall of the combustion chamber 4.

[0035] Figure 3 , Figure 4 He Ru Figure 7 As shown, in specific implementation, the gel propellant 5 includes gel fuel 501 and gel oxidant 502. After the gel oxidant 502 and gel fuel 501 are injected into the injector 1 body respectively, the gel fuel 501 flows to the outer annular groove 102, and the gel oxidant 502 flows to the inner annular groove 103. A portion of the gel fuel 501 and gel oxidant 502 flow to each pair of main injection holes 3 on the injector 1, and are sprayed into the combustion chamber 4 relative to each other and mixed for combustion. Another portion of the gel fuel 501, as a coolant, flows to the outer annular groove 102 with a certain tangential angle α and axial direction. At the oblique hole 2 with angle β, the coolant is sprayed from the oblique hole 2 onto the inner wall of the combustion chamber 4 with both axial and tangential velocities. It impacts the wall of the combustion chamber 4 obliquely from the oblique hole 2 and forms a spinning liquid film that adheres tightly to the inner wall of the combustion chamber 4. The oblique jet direction 7 of the oblique hole 2 improves the circumferential spreading degree of the coolant after impacting the wall and the circumferential uniformity of the coverage of the combustion chamber 4 wall. It also reduces the contact between the gel fuel 501 as coolant sprayed from the oblique hole 2 and the gel oxidant 502, increases the distribution of coolant near the impact point, improves the uniformity of coolant coverage on the wall, and improves the cooling performance.

[0036] Specifically, in this embodiment, when using gel fuel 501 as the coolant, the percentage of coolant is selected to be no less than 30% to 45% of the total flow rate of gel fuel 501. For example, the coolant percentage can be 30%, 35%, 40%, 42%, 45% of the total amount of gel fuel 501, etc. There is no specific limitation on the percentage of coolant here. The percentage of coolant is adjusted according to the different cooling requirements of the thrust chamber to achieve the best matching of the cooling effect of the head weld and throat of the thrust chamber and improve the cooling performance.

[0037] like Figure 5 As shown, specifically in this embodiment, the aspect ratio of the oblique hole 2 is 3 to 8, that is, the length L of the oblique hole 2 is... c With the diameter Φ of the inclined hole 2 d The ratio A r 3≤A r ≤8. For example, the aspect ratio A rIt can be 3, 4, 6, 7, 8, etc., and here we are referring to the aspect ratio A. r Without specific limitations, when selecting the length-to-diameter ratio A of the oblique hole 2... r When the length-to-diameter ratio is 3 to 8, a certain length-to-diameter ratio A is processed. r The inclined hole 2 ensures stable impact of the coolant jet against the wall and improves the machining accuracy of the machine tool. It enhances the stability of the jet and improves the reliability of the machine tool drill bit in machining the inclined hole 2.

[0038] like Figure 3 As shown, specifically in this embodiment, the tangential angle α is: 40°≤α≤70°. The tangential angle α can be 40°, 50°, 65°, 70°, etc. Here, the tangential angle α of the oblique hole 2 is not specifically limited. When the coolant is sprayed out from the oblique hole 2, the tangential angle α of the oblique hole 2 provides a tangential velocity component for the coolant, improving the spread and uniformity of the coolant along the circumferential direction of the combustion chamber 4 wall after impact, increasing the amount of coolant distributed near the impact point, and improving the cooling capacity for the thrust chamber head weld, thus achieving reliable cooling of the head weld.

[0039] like Figure 4 As shown, specifically in this embodiment, the axial angle β is: 10°≤β≤40°. The axial angle β can be 10°, 20°, 27°, 35°, 40°, etc. Here, the axial angle β of the oblique hole 2 is not specifically limited. When the coolant is ejected from the oblique hole 2, the coolant's axial angle β is a small angle impacting the wall. This small angle impact generates a large axial velocity, providing the coolant with the power to reach the throat. This increases the proportion of coolant moving along the combustion chamber 4 wall towards the throat, effectively protecting and cooling the throat, and providing optimal cooling for the throat.

[0040] As one possible approach, when the tangential angle α = 60°, the axial angle β = 30°, and the coolant percentage is 40%, the throat temperature of the thrust chamber is 1260°C, the head and body weld temperature is below 700°C, the thrust chamber has a cumulative working time of over 1000 seconds and a cumulative working cycle of over 30,000 times, exhibiting high operational reliability. The injector 1 provides good cooling effect on the inner wall of the combustion chamber 4.

[0041] like Figure 6 As shown, specifically in this embodiment, the oblique holes 2 and the main injection holes 3 are staggered in the circumferential direction, which reduces the mixing of coolant at the oblique holes 2 and gel oxidant 502 at the main injection holes 3, reduces the interference of the main injection holes 3 on the coolant jet, and improves the cooling effect of the injector 1 body on the combustion chamber 4.

[0042] like Figure 6As shown, specifically in this embodiment, the number of oblique holes 2 is equal to the number of pairs of main injection holes 3. For example, if there are 3 pairs of main injection holes 3, then there are 3 oblique holes 2 surrounding the main injection holes 3; if there are 4 pairs of main injection holes 3, then there are 4 oblique holes 2 surrounding the main injection holes 3; if there are 6 pairs of main injection holes 3, then there are 6 oblique holes 2 surrounding the main injection holes 3. Here, there is no specific limitation on the number of oblique holes 2 and the number of pairs of main injection holes 3. The fact that the number of oblique holes 2 is equal to the number of pairs of main injection holes 3 ensures that the flow rate of the coolant jetting from the oblique holes 2 meets the cooling requirements and improves the protection effect on the inner wall surface of the combustion chamber 4.

[0043] Specifically, in this embodiment, the injection pressure drop of the inclined hole 2 can be designed using the following formula:

[0044]

[0045] In the formula, q m,nj C is the flow rate of the gel coolant. d ρ is the flow coefficient of the cooling holes; A is the flow area of ​​the cooling holes; nj N is the density of the gel propellant; N is the gel-to-liquid ratio of the gel propellant; ΔP w The pressure drop during water testing. To determine the relationship between the coolant injection pressure drop at orifice 2 and the water injection pressure drop during testing, a flow resistance test under cold conditions is required, with a water flow rate of q. m At that time, the injection pressure drop is ΔP w At this flow rate, the injection pressure drop of gel propellant 5 is ΔP. nj At this point, the gel-to-liquid ratio of the gel propellant can be determined to be... Based on the above formula, the flow rate q of the gel coolant at the inclined hole 2 was calculated. m,nj By selecting an appropriate injection pressure drop, the stability of the gel propellant 5 as a coolant jet is improved, and the coolant is stably injected into the inner wall of the combustion chamber 4 to form a spin-type liquid film, ensuring reliable cooling of the head and throat welds of the combustion chamber 4.

[0046] like Figure 8 As shown, specifically in this embodiment, each oblique hole 2 is provided with an enlarged hole structure 201. The connecting surface 6 connecting the enlarged hole structure 201 and the oblique hole 2 is perpendicular to the axis of the oblique hole 2. The connecting surface 6 is located at one end of the injector body near the combustion chamber 4. The diameter D of the connecting surface 6 is greater than the hole diameter d of the oblique hole 2.

[0047] Specifically, in this embodiment, the enlarged hole structure 201 is arranged coaxially with the oblique hole 2. This reduces the possibility of the coolant jet impacting the connecting surface 6 and forming an unstable jet, thus enhancing the stability and reliability of the jet from the oblique hole 2.

[0048] Specifically, in this embodiment, the machining range of the diameter D of the connecting surface 6 is: 3d ≤ D ≤ 5d. To address the problem of drill bit breakage and low machining accuracy during the machining of the inclined hole 2 due to an excessively large inclination angle between the drill bit and the machining surface, a large-diameter milling cutter with good rigidity is used before machining the inclined hole 2. The diameter of the milling cutter is 3 to 5 times the diameter d of the inclined hole 2. The connecting surface 6 is machined on the injector 1 perpendicular to the axial direction of the inclined hole 2 using the milling cutter. The diameter D of the connecting surface 6 is consistent with the diameter of the milling cutter to ensure good machinability of the inclined hole 2. For example, the diameter D of the connecting surface 6 can be 3d, 4d, 5d, etc. There is no specific limitation on the diameter D of the connecting surface 6 here. Increasing the diameter D of the connecting surface 6 helps to improve the stability of the jet formed after the coolant flows out of the inclined hole 2, and improves the spreading and development of the coolant on the wall of the combustion chamber 4.

[0049] Meanwhile, the present invention provides a thrust chamber including a head, a body and an injector 1, characterized in that the injector 1 is any of the above-mentioned injectors 1, the injector 1 is used to connect gel fuel 501 and gel oxidant 502, one end of the injector 1 near the body is connected to the combustion chamber 4, when the gel fuel 501 is used as a coolant, the coolant sprayed from the oblique hole 2 in the injector 1 improves the cooling effect on the body of the thrust chamber.

[0050] It should be noted that, after testing and verification of a 4MPa pressure gel bicomponent 25N thrust chamber and a 4MPa pressure gel bicomponent 40N thrust chamber in a certain system, the throat temperature of the thrust chamber is less than 1300℃ and the head and body weld temperature is less than 700℃, with a high temperature margin, so that the cooling effect of the head and body weld and the throat is optimally matched.

[0051] In the description of the above embodiments, specific features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments or examples.

[0052] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. An injection device, characterized in that, The device includes an injector body. The injector body has at least three oblique holes and multiple pairs of main injection holes on its injection surface near the combustion chamber. The oblique holes surround the main injection holes. An axial angle β exists between the axial direction of the oblique holes and the axial direction of the injector body, and a tangential angle α exists between the projection line of the axial direction of the oblique holes onto the injection surface and the radial direction of the injection surface. The oblique holes are used to obliquely and spin-eject coolant into the inner wall of the combustion chamber. The gel propellant includes gel fuel and gel oxidant. After the gel oxidant and gel fuel are injected into the injector body respectively, the... The gel fuel flows to the outer annular groove, and the gel oxidant flows to the inner annular groove. A portion of the gel fuel and the gel oxidant flow to each pair of main injection holes on the injector, where they are sprayed into the combustion chamber and mixed for combustion. Another portion of the gel fuel, acting as coolant, flows to the oblique holes on the outer annular groove with a certain tangential angle α and an axial angle β. This allows the coolant to have both axial and tangential velocities when sprayed from the oblique holes onto the inner wall of the combustion chamber. The coolant then obliquely impacts the wall of the combustion chamber from the oblique holes and forms a spinning liquid film that adheres tightly to the inner wall of the combustion chamber.

2. The injector according to claim 1, characterized in that, The aspect ratio of the oblique hole is 3 to 8.

3. The injector according to claim 1, characterized in that, The tangential angle α is: 40°≤α≤70°.

4. The injector according to claim 1, characterized in that, The axial angle β is: 10°≤β≤40°.

5. The injector according to claim 1, characterized in that, The oblique holes are staggered from the main injection holes in the circumferential direction.

6. The injector according to claim 1, characterized in that, The number of the oblique holes is equal to the logarithm of the main injection holes.

7. The injector according to claim 1, characterized in that, Each of the inclined holes is provided with an enlarged hole structure. The connecting surface of the enlarged hole structure to the inclined hole is perpendicular to the axis of the inclined hole, and the connecting surface is located at one end of the injector body near the combustion chamber. The diameter D of the connecting surface is larger than the aperture d of the inclined hole.

8. The injector according to claim 7, characterized in that, The enlarged hole structure is arranged coaxially with the inclined hole.

9. The injector according to claim 7, characterized in that, The processing range of the diameter D of the connecting surface is: 3d≤D≤5d.

10. A thrust chamber, comprising a head, a body, and an injector, characterized in that, The injector is the injector as described in any one of claims 1-9, the injector being used to introduce gel propellant and oxidant, and the end of the injector near the body being connected to the combustion chamber.

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