Single-component injector suitable for additive manufacturing and manufacturing method thereof

Abstract

The invention discloses a single-component injector suitable for additive manufacturing and a manufacturing method of the single-component injector. The single-component injector is mainly composed of an upper injection disc, an upper injection disc supporting structure, a capillary tube, an injector supporting structure and a lower injection disc with second capillary holes. The high degree of freedom of additive manufacturing in the manufacturing process of the single-component injector is utilized, design optimization suitable for additive manufacturing is carried out on the single-component injector, the size margin of the single-component injector is increased, a local supporting structure is optimized, the thermal resistance of an upper injection disc and a lower injection disc is increased, and the proper printing direction is selected; and the capabilities of low cost, high reliability and rapid manufacturing of the single-component injector are realized.

Description

Technical Field

[0001] The present invention belongs to the field of liquid engine design and manufacturing, and in particular relates to a single-component injector suitable for additive manufacturing and a design and manufacturing method thereof. Background Art

[0002] The monopropellant engine is a liquid attitude and orbit control engine widely used in rocket attitude control and long-term satellite orbit control. The monopropellant injector is an important component of the monopropellant engine, which plays an important role in evenly distributing the propellant to the catalyst bed, thereby achieving stable combustion and high performance of the monopropellant engine. Due to the thermal explosion characteristics of the monopropellant, in order to avoid the high temperature being transferred to the injector liquid accumulation cavity during the operation of the engine, resulting in the explosion of the engine during the secondary start, causing the rocket attitude to be out of control and the satellite life to be greatly reduced, the monopropellant injector is generally designed as a structure consisting of an upper injection disk, an insulation frame (support structure), a capillary, and a lower injection disk, so as to isolate heat and improve the safety of the engine operation. Among them, there is a liquid accumulation cavity in the upper injection disk, which is responsible for diverting the propellant together with the capillary. The insulation frame must have a large thermal resistance while providing structural support. The lower injection disk is responsible for docking the capillary and the insulation frame, and is also connected to the catalyst bed.

[0003] However, in actual design and manufacturing, since dozens of capillaries need to be welded on the monopropellant injector at the same time, and in order to ensure uniform distribution of propellant, the bending angle and size of each capillary must be controlled to be consistent, and the upper and lower injection plates must maintain appropriate parallelism to ensure that the engine thrust line is centered. The entire monopropellant injector has dozens of welds and needs to be welded at one time. Once a weld fails, the product will be scrapped. This requires that the deformation of each capillary must be controlled during welding, and the position of the upper and lower injection plates must have a high degree of accuracy, and the welding must be reliable.

[0004] The above problems lead to the difficulty of processing single-component injectors, many special processes, long production cycle, low yield rate and high cost, which seriously restricts its mass-production and low-cost manufacturing capabilities. Summary of the invention

[0005] The present invention aims to provide a monocomponent injector suitable for additive manufacturing and a manufacturing method thereof, which can reduce the difficulty of welding, reduce the precision requirements of parts, reduce the manufacturing difficulty of monocomponent engines, improve the yield rate, reduce production costs, improve working reliability, and also provide a possibility for mass production.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] Monocomponent injectors adapted to additive manufacturing, including:

[0008] An upper injection plate, the upper injection plate comprising an engine fixing interface, a valve connection interface, a liquid accumulation cavity and a capillary hole, wherein the valve connection interface is located in the inner area of ​​the engine fixing interface, the liquid accumulation cavity and the capillary hole are located in the inner area of ​​the valve connection interface, and the blind hole on the end surface of the upper injection plate constitutes the liquid accumulation cavity, and the passage opened on the bottom surface of the blind hole constitutes a first capillary hole;

[0009] A lower injection plate, wherein the lower injection plate is arranged in parallel with the upper injection plate and spaced apart, and a second capillary hole penetrating through the lower injection plate is opened on the lower injection plate;

[0010] Capillaries, a plurality of said capillaries are symmetrically arranged between the upper injection disk and the lower injection disk, and the first end of the capillaries is connected to the first capillary hole, and the second end of the capillaries is connected to the second capillary hole, and the capillaries are in a curved shape, wherein the distance from the first end of the capillaries to the symmetry center is smaller than the distance from the second end to the symmetry center, so that the capillaries are distributed on the generatrix of the rotating body whose outer diameter gradually increases from the upper injection disk to the lower injection disk;

[0011] An upper injection disk support structure, wherein a plurality of the upper injection disk support structures are centrally symmetrically arranged between the upper injection disk and the lower injection disk, one end of the upper injection disk support structure is connected to the upper injection disk, the upper injection disk support structure comprises a curved surface having the same curvature as the capillary surface (the capillary surface is a cylindrical surface, and the surface of the upper injection disk support structure is also connected to the capillary through the cylindrical surface), and the upper injection disk support structure is connected to the capillary through the curved surface;

[0012] Injector support structure, multiple injector support structures are symmetrically arranged between the upper injection disk and the lower injection disk and located on the outside of the upper injection disk support structure, the injector support structure is Y-shaped, the forked section of the Y-shape is connected to the lower injection disk, the main section of the Y-shape is connected to the upper injection disk, and the heat transfer area of ​​the forked section is smaller than the heat transfer area of ​​the main section.

[0013] Furthermore, the plurality of injector support structures are independent of each other and are distributed at intervals without connection with each other.

[0014] Furthermore, the plurality of capillaries are distributed on at least two coaxial busbars of the rotating bodies with different shapes, and the capillaries on the busbars of different rotating bodies do not affect each other, thereby increasing the number and distribution density of the capillaries without interfering with each other.

[0015] Furthermore, the engine fixing interface is a plurality of connection holes with equal central angles evenly distributed on the same circumference.

[0016] Furthermore, the valve connection interface is a plurality of connection holes with equal central angles evenly distributed on the same circumference.

[0017] Furthermore, the first capillary pores are distributed on at least two concentric circles with different diameters, and the numbers of the first capillary pores on different circles are different. The first capillary pores on the same circle are evenly distributed at equal central angles.

[0018] Furthermore, the second capillary pores are distributed on at least two concentric circles with different diameters, and the numbers of the second capillary pores on different circles are different. The second capillary pores on the same circle are evenly distributed at equal central angles.

[0019] Furthermore, the capillary tube includes a curved segment and a straight segment, and the capillary tube is connected to the first capillary hole and the second capillary hole respectively through the straight segment;

[0020] The upper injection plate support structure extends from a tangent line at the junction of the curved segment and the straight segment on the capillary toward the upper injection plate.

[0021] Furthermore, the number of the injector support structures is less than the number of the upper injection tray support structures. The relatively small number of injector support structures form a larger spacing between each other, which is convenient for the capillary powder cleaning process inside after printing, and on the other hand, cooperates with the upper injection tray support structure to reduce the amount of printing material.

[0022] The manufacturing method of the monocomponent injector adapted for additive manufacturing as described above is printed and formed by additive manufacturing, and includes:

[0023] The end surface of the lower injection disk is used as the starting position of additive printing, and the end surface of the upper injection disk is used as the ending position of additive printing, and the printing of the lower injection disk, the injector support structure, the capillary, the upper injection disk support structure and the upper injection disk is completed in sequence.

[0024] further,

[0025] The printing thickness of the upper injection plate and the lower injection plate includes a cutting margin for subsequent machining;

[0026] The ratio of the inner diameter to the wall thickness of the capillary is between 0.5 and 1.0, and the wall thickness of the capillary is greater than or equal to 0.8 mm;

[0027] Small holes are reserved at the engine fixing interface and the valve connection interface;

[0028] The length ratio of the bifurcated section to the main section of the Y-shaped injector support structure is 1:1, and the heat transfer area of ​​the bifurcated section is 0.25 to 0.5 of the heat transfer area of ​​the main section;

[0029] The aperture of the first capillary pores is smaller than that of the second capillary pores, and the number and distribution positions of the first capillary pores are consistent with the number and distribution positions of the second capillary pores.

[0030] Furthermore, the end surface of the lower injection plate as the starting position of the additive printing includes a circle of annular protrusions, and the inner side of the inner ring of the annular protrusion is the first capillary printing end surface. The thickness of the annular protrusion can be used as a margin for subsequent machining, and also as an interface for butt welding with the catalyst bed.

[0031] Compared with the prior art, the present invention discloses a monopropellant injector manufactured by additive manufacturing and an additive manufacturing method thereof. By rationally arranging the structure of the monopropellant injector, applying the topological optimization design method, optimizing the local support structure, increasing the thermal resistance of the upper and lower injection disks, and selecting the appropriate printing direction, the monopropellant injector is manufactured in one piece by additive manufacturing technology, which reduces the welding difficulty, reduces the precision requirements of parts, reduces the manufacturing difficulty of the monopropellant engine, improves the yield rate, reduces the production cost, and improves the working reliability. At the same time, it also provides a possible solution for the mass production of monopropellant injectors. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 is a stereoscopic view of a monocomponent injector manufactured by additive manufacturing in the present invention;

[0033] Figure 2 is a schematic diagram of a single component interface manufactured by additive manufacturing in the present invention;

[0034] In the figure: 1—upper injection plate; 2—upper injection plate supporting structure; 3—capillary; 4—injector supporting structure; 5—lower injection plate; 6—engine fixing interface; 7—valve connection interface; 8—liquid accumulation chamber and capillary hole; 9—second capillary hole. DETAILED DESCRIPTION

[0035] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments, but it should not be understood that the scope of the subject matter described in the present invention is limited to the following embodiments. Without departing from the above-mentioned technical ideas of the present invention, various modifications, substitutions and changes made according to the common technical knowledge and customary means in the field are included in the scope of the present invention.

[0036] like Figure 1 and Figure 2 As shown, a single-component injector suitable for additive manufacturing designed in this embodiment is composed of an upper injector plate 1 with a liquid accumulation chamber and a first capillary hole, an upper injector plate support structure 2, a capillary 3, an injector support structure 4 and a lower injector plate 5 with a second capillary hole 9.

[0037] In this embodiment, considering the poor roughness of the product directly generated by additive manufacturing, the thickness of the upper injection disk 1 is increased as a margin for subsequent machining. Since the diameter of the upper injection disk 1 is quite different from that of the lower injection disk 5, traditional additive manufacturing requires additional support. After fully considering the process characteristics of additive manufacturing and evaluating the printing direction, considering the small aperture of the capillary pores, in order to ensure the quality of the capillary pores, the lower injection disk 5 is selected as the printing starting end face and the upper injection disk 1 is selected as the printing ending end face. At the same time, in order to avoid deformation of the upper injection disk 1 during printing, the present invention adds support outside the capillary 3, and the position is tangent to the vertical part of the capillary 3 (in additive manufacturing, the printing direction that ensures the best product quality is the vertical direction. Therefore, in order to reduce the deformation of the injector during manufacturing, it is selected to be tangent to the vertical section of the capillary 3) and extends to the upper injection disk 1. In order to ensure the smoothness and structural strength of the inner diameter of the capillary tube 3 and to ensure that the propellant flows evenly in the injector, the ratio of the inner diameter of the capillary tube 3 to the wall thickness is controlled to be about 0.5 to 1.0.

[0038] Taking into account the poor quality of threaded holes generated by additive manufacturing, the interface of the single-component injector reserves small holes of φ1mm to φ2mm where threaded holes need to be generated, and reserves the post-processing size.

[0039] For the injector support structure 4, in order to increase the thermal resistance as much as possible and reduce the weight, four "Y"-shaped tree fork structures are used as supports, in which the main trunk of the tree fork starts from the upper injection disk 1, and two tree forks are divided at a position about 1 / 2 of the height between the upper injection disk 1 and the lower injection disk 5, thereby improving the working safety and reliability of the injector.

[0040] The thickness of the lower injection plate 5 is increased to reserve the size for post-processing, and the second capillary hole 9 is designed in the same position and direction as the first capillary hole on the upper injection plate 1 . The size of the second capillary hole 9 can be adaptively increased according to the size of the lower injection plate 5 .

[0041] Through the above-mentioned design and manufacturing method, a single-component injector suitable for additive manufacturing can be designed and manufactured, which has low cost and rapid manufacturing capabilities and high reliability.

[0042] like Figure 2 As shown in the middle left figure, the specific performance is as follows: the upper injection plate 1 has three areas: the engine fixing interface 6 has 4 connection holes evenly distributed around the circumference; the valve connection interface 7 has 6 connection holes evenly distributed around the circumference, the liquid accumulation cavity and the capillary hole 8 are centered, and there are 2 circles of first capillary holes distributed inside, the inner circle has 4 first capillary holes evenly distributed around the circumference, and the outer circle has 12 first capillary holes evenly distributed around the circumference. The engine fixing interface 6 and the valve connection interface 7 reserve a φ1mm aperture for later hole expansion and positioning. All holes are in Figure 2 The above are symmetrical on the left and right.

[0043] The upper injection plate support structure 2 is tangent to the vertical section of the outer wall of the capillary 3, with a total of 12 pieces, extending upward along the capillary 3 to the upper injection plate 1 to ensure that the upper injection plate 1 is flat and not tilted during printing. The capillary 3 protrudes outward (through the curved section) to present a "birdcage" shape, and the wall thickness of the capillary 3 is not less than 0.8mm to ensure that the capillary 3 conforms to the printer principle of additive manufacturing and the structure meets the requirements. The "birdcage" type is convenient for spatial layout on the one hand, and can increase the length of the capillary 3 on the other hand, which is beneficial to increasing the thermal insulation effect of the injector. Figure 1 The middle capillaries 3 are divided into two distribution forms, of which 4 are without the upper injection disk support structure 2, and the outer diameter change trend of the cross-section of the rotating body where these 4 capillaries 3 are located is relatively small (that is, the curvature of the curved section is smaller, and it is closer to a straight line), and the other 12 are provided with the upper injection disk support structure 2, and the outer diameter change trend of the cross-section of the rotating body where these 12 capillaries 3 are located is relatively larger (that is, the curvature of the curved section is larger and more curved).

[0044] The injector support structure 4 is topologically optimized through coupling of structural stress and heat transfer, and adopts four "Y"-shaped tree fork structures as support, wherein the trunk of the tree fork starts from the upper injector disk 1, and two "tree forks" are separated from it at about 1 / 2 height, and the heat transfer area of ​​the "tree fork" is about 0.25 to 0.5 times the heat transfer area of ​​the "tree trunk", so as to reduce the heat transferred from the lower injector disk 5 to the upper injector disk 1, avoid the propellant thermal explosion caused by excessive temperature of the accumulating liquid cavity, and improve the working safety and reliability of the injector.

[0045] like Figure 2 As shown in the middle right figure, the lower injection plate 5 is connected to the capillary 3 and the injector support structure 4, and has two inner and outer circles of second capillary holes 9 on its lower end surface, with 4 inner circles and 12 outer circles, which are evenly distributed inside and outside. The aperture is the same as that of the first capillary holes of the upper injection plate 1, and the position and orientation are the same. Figure 2 Symmetrical on the upper left and right.

[0046] By arranging the interface of the upper injection disk 1 and the distribution of the first capillary pores in the liquid accumulation chamber, adding the upper injection disk support structure 2, optimizing the injector support structure 4, and selecting a reasonable additive manufacturing direction, a single-component injector suitable for additive manufacturing can be realized.

[0047] The above are the main concepts of the invention. All single-component injectors and manufacturing methods designed according to the concepts of the present invention fall within the protection scope of the present invention.

Claims

1. A monocomponent injector adapted for additive manufacturing, characterized in that: include: An upper injection plate (1), the upper injection plate (1) comprising an engine fixing interface (6), a valve connection interface (7), a liquid accumulation cavity and a capillary hole (8), wherein the valve connection interface (7) is located in the inner area of ​​the engine fixing interface (6), the liquid accumulation cavity and the capillary hole (8) are located in the inner area of ​​the valve connection interface (7), and the blind hole on the end surface of the upper injection plate (1) constitutes the liquid accumulation cavity, and the passage opened on the bottom surface of the blind hole constitutes a first capillary hole; A lower injection plate (5), the lower injection plate (5) being arranged in parallel and spaced relation with the upper injection plate (1), and having a second capillary hole (9) penetrating the lower injection plate (5); Capillaries (3), wherein a plurality of the capillaries (3) are symmetrically arranged between an upper injection disk (1) and a lower injection disk (5), and a first end of the capillary (3) is connected to a first capillary hole, and a second end of the capillary (3) is connected to a second capillary hole (9), and the capillary (3) is in a curved shape, wherein a distance from the first end of the capillary (3) to the symmetry center is smaller than a distance from the second end to the symmetry center, so that the capillaries (3) are distributed on a generatrix of a rotating body whose outer diameter gradually increases from the upper injection disk (1) to the lower injection disk (5); An upper injection disk support structure (2), wherein a plurality of the upper injection disk support structures (2) are centrally symmetrically arranged between the upper injection disk (1) and the lower injection disk (5), one end of the upper injection disk support structure (2) is connected to the upper injection disk (1), the upper injection disk support structure (2) comprises a curved surface having the same curvature as the surface of the capillary (3), and the upper injection disk support structure (2) is connected to the capillary (3) via the curved surface; An injector support structure (4), wherein a plurality of the injector support structures (4) are symmetrically arranged between an upper injector disk (1) and a lower injector disk (5) and are located outside the upper injector disk support structure (2), the injector support structure (4) is Y-shaped, the forked section of the Y-shape is connected to the lower injector disk (5), the main section of the Y-shape is connected to the upper injector disk (1), and the heat transfer area of ​​the forked section is smaller than the heat transfer area of ​​the main section.

2. The monocomponent injector adapted for additive manufacturing according to claim 1, characterized in that: The engine fixing interface (6) is a plurality of connection holes with equal central angles evenly distributed on the same circumference.

3. The monocomponent injector adapted for additive manufacturing according to claim 1, characterized in that: The valve connection interface (7) is a plurality of connection holes with equal central angles evenly distributed on the same circumference.

4. The monocomponent injector adapted for additive manufacturing according to claim 1, characterized in that: The first capillary pores are distributed on at least two concentric circles with different diameters, and the numbers of the first capillary pores on different circles are different. The first capillary pores on the same circle are evenly distributed according to equal central angles.

5. The monocomponent injector adapted for additive manufacturing according to claim 1, characterized in that: The second capillary holes (9) are distributed on at least two concentric circles with different diameters, and the number of second capillary holes (9) on different circles is different. The second capillary holes (9) on the same circle are evenly distributed according to equal central angles.

6. The monocomponent injector adapted for additive manufacturing according to claim 1, characterized in that: The capillary tube (3) comprises a curved segment and a straight segment, and the capillary tube (3) is connected to the first capillary hole and the second capillary hole (9) respectively through the straight segment; The upper injection disk support structure (2) extends from a tangent line at the junction of the curved segment and the straight segment on the capillary (3) toward the upper injection disk (1).

7. The monocomponent injector adapted for additive manufacturing according to claim 1, characterized in that: The number of the injector support structures (4) is smaller than the number of the upper injection plate support structures (2).

8. The method for manufacturing a monocomponent injector adapted for additive manufacturing according to claim 1, characterized in that: Printing is done by additive manufacturing and includes: The end surface of the lower injection disk (5) is used as the starting position of additive printing, and the end surface of the upper injection disk (1) is used as the ending position of additive printing, and the printing and forming of the lower injection disk (5), the injector support structure (4), the capillary (3), the upper injection disk support structure (2) and the upper injection disk (1) are completed in sequence.

9. The manufacturing method according to claim 8, characterized in that: The printing thickness of the upper injection plate (1) and the lower injection plate (5) includes a cutting margin for subsequent machining; The ratio of the inner diameter to the wall thickness of the capillary (3) is between 0.5 and 1.0, and the wall thickness of the capillary (3) is greater than or equal to 0.8 mm; Small holes are reserved at the engine fixing interface (6) and the valve connecting interface (7); The length ratio of the Y-shaped bifurcated section to the main section of the injector support structure (4) is 1:1, and the heat transfer area of ​​the bifurcated section is 0.25 to 0.5 of the heat transfer area of ​​the main section; The pore size of the first capillary pores is smaller than the pore size of the second capillary pores (9), and the number and distribution positions of the first capillary pores are consistent with the number and distribution positions of the second capillary pores (9).

10. The manufacturing method according to claim 8, characterized in that: The end surface of the lower injection plate (5) serving as the starting position for additive printing comprises a circle of annular protrusions, and the inner side of the inner ring of the annular protrusion is the first capillary printing end surface.

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