A 3D printing integrated injector based on eccentric injection unit
Through integrated 3D printing configuration design, the problems of numerous welds and poor reliability in the injector structure have been solved, achieving zero welds in the injector, improving reliability and cooling efficiency, and making it suitable for liquid rocket engines in the aerospace field.
Patent Information
- Application Number
- CN202411971448.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-30
- Publication Date
- 2025-11-07
- Estimated Expiration
- 2044-12-30
AI Technical Summary
Existing injector structures have many welds, poor reliability, are prone to ablation, are prone to misassembly, and the circumferential gap is prone to deviating from the design value. Furthermore, they cannot be integrated into 3D printing, especially the three-base structure, which cannot be integrated.
The design adopts an integrated 3D printing configuration, which integrates the three bases, two cavities, and injection units into a single structure. The outer ring is an eccentric injection unit, and the inner ring is a coaxial injection unit. The design incorporates eccentricity and teardrop-shaped holes to prevent welding deformation and blockage, and adds a self-supporting structure to prevent collapse.
The zero-weld-seam design of the injector has been achieved, which improves reliability, avoids nozzle and wall erosion, enhances cooling efficiency, and improves the yield rate and production convenience of 3D printing.
Smart Images
Figure CN119957387B_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The application relates to a 3D printing integrated injector based on an eccentric injection unit, which can be used in the technical field of aerospace. BACKGROUND
[0002] The injector is a key component of the liquid rocket engine thrust chamber, which functions to inject fuel and oxidizer into the combustion chamber for mixing and combustion, and the high-temperature and high-pressure gas (about 3000K) generated enters the nozzle to accelerate to supersonic speed and then generate thrust. The common injector is a three-bottom (one bottom, two bottom, three bottom) two-cavity (oxidizer cavity and fuel cavity) structure, which is generally composed of a plurality of injection units and a two-bottom brazing joint. The one bottom of the thrust chamber injector is generally a porous sweating panel made of GH3030 wire mesh sintering, which cools the thrust chamber. In the traditional injector structure, hundreds of solder rings are used to form hundreds of solder joints. Once the solder joint fails, it will cause cavity connection and explosion, and the reliability is poor. The eccentric injection unit ring gap is designed by uneven eccentricity to change the fuel circumferential flow distribution, effectively improve the downstream temperature of the larger side of the ring gap, and change the combustion chamber temperature distribution to prevent the body wall from overheating. It is generally arranged in the outermost circle of the injector. In the actual production process, the state of the injection unit to the state of the thrust chamber will go through many welding processes. The eccentric injection unit ring gap is easily deformed by welding and deviates from the design value, thereby ablation of the nozzle or ablation of the wall, and the eccentric injection unit is easily misassembled. The eccentric injection unit ring gap is also easily blocked by excess material, thereby ablation of the nozzle or the body wall. If the injector adopts a 3D printing scheme, the one bottom is made of wire mesh sintering and cannot be integrated printed; the two bottom is prone to printing collapse, so the three bottom cannot be integrated printed. SUMMARY
[0003] The application solves the technical problem of overcoming the shortcomings of the prior art and providing a 3D printing integrated injector structure based on an eccentric injection unit, which reduces the welding joint to zero from the structural design and is convenient for 3D printing, improves the reliability of the injector structure, and avoids ablation of the nozzle and the body wall.
[0004] The application aims to solve the problems of the eccentric injection unit-based injector, such as many welds, poor reliability, easy ablation of the nozzle and wall, easy misassembly, deviation of the actual annular gap from the design value, easy blockage of the annular gap by excess material, and the inability to integrate 3D printing of the one bottom and three bottoms. The integrated 3D printing configuration design scheme is adopted for the injector, the three-bottom two-cavity and a plurality of injection units are designed as a whole structure, the outermost circle of injection units adopts an eccentric injection unit, and the inner circle of injection units adopts a coaxial injection unit. The fuel nozzle of the eccentric injection unit adopts a small-diameter radial hole, which can avoid blockage of the nozzle by excess material and avoid ablation of the nozzle and wall. Meanwhile, a plurality of centrifugal grooves are provided on the one bottom to improve the cooling efficiency of the thrust chamber and compensate for the inapplicability of the multi-hole sweating panel to 3D printing. A skeleton support is designed between the two bottom and the three bottom to avoid collapse during printing and realize integrated printing of the three bottoms and zero-welding of the injector. The round hole adopts a water droplet-shaped hole design to avoid collapse during printing.
[0005] The technical scheme provided by the application is as follows:
[0006] A 3D printing integrated injector based on an eccentric injection unit, comprising a 3D printing integrated injector body, the injector body comprising a one bottom, a two bottom, a three bottom, an injection unit, and an outer cylinder, the one bottom and the three bottom being connected to the two ends of the outer cylinder, the two bottom being located between the one bottom and the three bottom and connected to the inner wall of the outer cylinder, the three bottom and the two bottom forming an oxidant cavity, the one bottom and the two bottom forming a fuel cavity, the outer cylinder being provided with a fuel inlet for injecting fuel into the fuel cavity, the three bottom being provided with an oxidant inlet for injecting oxidant into the oxidant cavity; the injection unit is connected between the two bottom and the one bottom; the injection unit is provided with a first injection channel and a second injection channel, one end of the first injection channel being communicated to the space on the side of the one bottom away from the two bottom, the other end being communicated to the oxidant cavity, one end of the second injection channel being communicated to the space on the side of the one bottom away from the two bottom, the other end being communicated to the fuel cavity.
[0007] The three bottom and the two bottom are provided with a self-supporting structure.
[0008] The injection unit comprises a plurality of coaxial injection units and a plurality of eccentric injection units, and the eccentric injection units are arranged at the outer circle of the plurality of coaxial injection units.
[0009] The coaxial injection unit comprises a coaxial centrifugal oxygen nozzle and a coaxial fuel nozzle, the coaxial fuel nozzle is arranged outside the coaxial centrifugal oxygen nozzle and connected to the coaxial centrifugal oxygen nozzle at one end, the coaxial centrifugal oxygen nozzle is provided with a first central hole, a first annular groove is formed between the coaxial fuel nozzle and the coaxial centrifugal oxygen nozzle, and the first central hole and one end of the first annular groove are both communicated to one side of the bottom away from the two bottoms; the coaxial centrifugal oxygen nozzle is provided with a first tangential hole, the first tangential hole is communicated with the first central hole and the oxidant cavity, the coaxial fuel nozzle is provided with a first radial hole, and the first radial hole is communicated with the first annular groove and the fuel cavity.
[0010] The eccentric injection unit comprises an eccentric centrifugal oxygen nozzle and an eccentric fuel nozzle, the eccentric fuel nozzle is arranged outside the eccentric centrifugal oxygen nozzle and connected to the eccentric centrifugal oxygen nozzle at one end, the eccentric centrifugal oxygen nozzle is provided with a second central hole, a second annular groove is formed between the eccentric fuel nozzle and the eccentric centrifugal oxygen nozzle, the second central hole and one end of the second annular groove are both communicated to one side of the bottom away from the two bottoms, the second annular groove is arranged outside the second central hole, the inner circular axis of the second annular groove deviates from the axis of the second central hole and deviates to one side of the axis of the injector body; the eccentric centrifugal oxygen nozzle is provided with a second tangential hole, the second tangential hole is communicated with the oxidant cavity and the second central hole, the eccentric fuel nozzle is provided with a second radial hole, and the second radial hole is communicated with the fuel cavity and the second annular groove.
[0011] The maximum width of the second annular groove is a maximum annular gap L1, the minimum width of the second annular groove is a minimum annular gap L2, the distance between the axis of the inner diameter of the second annular groove and the axis of the second central hole is an eccentric distance L3, and the eccentric distance L3=(maximum annular gap L1-minimum annular gap L2) / 2.
[0012] The width L of the first annular groove=(maximum annular gap L1+minimum annular gap L2) / 2.
[0013] The surface of the bottom away from the two bottoms has a plurality of cylindrical protrusions, the centrifugal groove extends into the cylindrical protrusions, the diameter of the centrifugal groove in the part located in the cylindrical protrusions is greater than the diameter of the centrifugal groove in the part located in the bottom, and the diameter of the centrifugal groove in the part located in the bottom is in a flared shape; the cylindrical protrusions are provided with centrifugal through holes, and the centrifugal through holes are communicated with the fuel cavity and the centrifugal groove.
[0014] The eccentric centrifugal oxygen nozzle and the coaxial centrifugal oxygen nozzle both comprise a plurality of tangential holes, the coaxial fuel nozzle and the eccentric fuel nozzle comprise a plurality of radial holes, the tangential holes, the radial holes and the centrifugal through holes are all water-drop-shaped holes, the top end part of the water-drop-shaped hole is directed to the bottom, the top end angle of the water-drop-shaped hole ranges from 30 to 80°, and the length d of the water-drop-shaped hole of the eccentric fuel nozzle along the axial direction thereof is less than 0.9L.
[0015] Each of the injection units is surrounded by 3-6 centrifugal grooves, and the total throttling area of the centrifugal grooves accounts for 4-10% of the total throttling area of fuel outlets.
[0016] Compared with the prior art, the patent has the advantages that the patent designs a 3D printing integrated injector based on an eccentric injection unit, the injector is 3D printing integrated, has simple structure, good reliability, is convenient to produce, and the outermost circle is the eccentric injection unit and the inner circle is the coaxial injection unit, which avoids the influence of welding on the gap between nozzle rings, reduces the mixing ratio near the wall, and avoids ablation of the nozzle and the wall. The fuel nozzle of the eccentric injection unit adopts a small-diameter hole to avoid blockage of the nozzle by excess material. The centrifugal grooves have good atomization effect, can cool the thrust chamber, and make up for the difficulty of the porous sweating panel in 3D printing and complex processing technology. The water droplet-shaped circular hole design can also effectively form self-supporting, avoid collapse of the circular hole, blockage of the nozzle, and improve the first-time pass rate of 3D printing. The skeleton support between the second bottom and the third bottom avoids collapse during printing. The patent has been applied to a certain liquid oxygen-methane rocket engine, and can also be applied to liquid oxygen-kerosene rocket engines, liquid hydrogen-liquid oxygen rocket engines, aircraft engines, fuel boilers and many other fields, and has simple structure, easy popularization and low cost. BRIEF DESCRIPTION OF DRAWINGS
[0017] Figure 1 Fig. 1 is a schematic diagram of a 3D printing integrated injector based on an eccentric injection unit of the patent;
[0018] Figure 2 Fig. 1 is a schematic diagram of a 3D printing integrated injector based on an eccentric injection unit of the patent;
[0019] Figure 3 Fig. 1 is a schematic diagram of a 3D printing integrated injector based on an eccentric injection unit of the patent;
[0020] Figure 4 Fig. 1 is a schematic diagram of a 3D printing integrated injector based on an eccentric injection unit of the patent.
[0021] Fig. 1 is a schematic diagram of a 3D printing integrated injector based on an eccentric injection unit of the patent. DETAILED DESCRIPTION
[0022] In order to make the purpose, technical scheme and advantages of the patent more clear, the following will combine the drawings to further describe the embodiments disclosed by the patent.
[0023] The embodiments of the patent disclose a 3D printing integrated injector based on an eccentric injection unit, as shown in Figure 1As shown, the bottom 1, the second bottom 2, the third bottom 3, the coaxial injection unit 4, the eccentric injection unit 5, and the centrifugal groove 6 are integrally formed by 3D printing. The oxidation agent cavity is formed between the third bottom 3 and the second bottom 2, and a self-supporting structure is arranged therebetween. The fuel cavity is formed between the first bottom 1 and the second bottom 2. The oxidation agent cavity is provided with an oxidation agent inlet, and the fuel cavity is provided with a fuel inlet. The number of welds of the injector is zero. The outermost nozzle of the injector adopts the eccentric injection unit 5, and the remaining nozzles adopt the coaxial injection unit 4. Through such a layout, the uniformity of the spray and the wall ablation can be considered.
[0024] As shown in Figure 2 , the coaxial injection unit 4 includes a coaxial centrifugal oxygen nozzle 9 and a coaxial fuel nozzle 10, and the eccentric injection unit 5 includes an eccentric centrifugal oxygen nozzle 8 and an eccentric fuel nozzle 11, which are integrally formed by 3D printing. The eccentric injection unit 5 has uneven annular gap distribution, which can effectively improve the downstream temperature on the side with larger annular gap and prevent the overheat of the thrust chamber body by changing the circumferential flow distribution of the fuel. The annular gap of the coaxial fuel nozzle 10 is denoted by L. The eccentric injection unit 5 is eccentric by deviating from the center of the inner circle of the annular gap to one side of the center of the injector. The deviation distance is the eccentric distance L3. The eccentric distance L3 is defined as:
[0025]
[0026] And there is:
[0027]
[0028] The reference value of the eccentric distance L3 is 0 < L3 < 0.33L.
[0029] As shown in Figure 1 , 3 , a plurality of centrifugal grooves 6 are arranged on the first bottom 1 to improve the flow field temperature of the thrust chamber. Generally, there are 3-6 centrifugal grooves around each injection unit, and the total throttling area of the centrifugal grooves accounts for 4-10% of the total throttling area of the fuel outlet.
[0030] As shown in Figure 2 , 3As shown in Fig. 4, the eccentric centrifugal oxygen nozzle 8 and the coaxial centrifugal oxygen nozzle 9 are provided with a plurality of tangential holes (the second tangential hole of the eccentric centrifugal oxygen nozzle 8 and the first tangential hole of the coaxial centrifugal oxygen nozzle 9), the axes of the tangential holes are perpendicular to and do not intersect with the axis of the injection unit, the coaxial fuel nozzle 10 and the eccentric fuel nozzle 11 are provided with a plurality of radial holes (the first radial hole of the coaxial fuel nozzle 10 and the second radial hole of the eccentric fuel nozzle 11), the axes of the radial holes are perpendicular to and pass through the axis of the injection unit; the tangential holes, the radial holes and the plurality of centrifugal through holes contained in the centrifugal groove 6 are all designed as water-drop-shaped holes. Through such a layout, the flow distribution at the outlet of the injection unit can be more uniform, which is conducive to the uniformity of the temperature at the outlet of the nozzle, the water-drop-shaped holes form self-supporting, which prevents the printing from collapsing and clogging the nozzle, and improves the one-time qualification rate of 3D printing. The top angle of the water-drop-shaped hole is generally in the range of 30-80°. The length d of the water-drop-shaped hole of the eccentric fuel nozzle 11 along the axial direction thereof is small, which can prevent excess material from clogging the eccentric injection unit in the edge area, and d is generally ≤0.9L.
[0031] The contents not described in detail in the specification of the present application are the known technology of those skilled in the art.
[0032] The present application is described in detail above in combination with the specific embodiments and exemplary examples, but these descriptions cannot be understood as limiting the present application. Those skilled in the art understand that the technical solutions and embodiments of the present application can be variously replaced, modified or improved without departing from the spirit and scope of the present application, and these all fall within the scope of the present application. The protection scope of the present application is subject to the appended claims.
Claims
1. A 3D printing integrated injector based on an eccentric injection unit, characterized in that: The injector body is integrally formed by 3D printing, and comprises a bottom (1), a second bottom (2), a third bottom (3), a spraying unit and an outer cylinder body, the bottom (1) and the third bottom (3) are connected to two ends of the outer cylinder body, the second bottom (2) is located between the bottom (1) and the third bottom (3) and is connected to the inner wall of the outer cylinder body, an oxidant cavity is formed between the third bottom (3) and the second bottom (2), a fuel cavity is formed between the bottom (1) and the second bottom (2), the outer cylinder body is provided with a fuel inlet for injecting fuel into the fuel cavity, the third bottom (3) is provided with an oxidant inlet for injecting oxidant into the oxidant cavity; the spraying unit is connected between the second bottom (2) and the bottom (1); the spraying unit is provided with a first spraying channel and a second spraying channel, one end of the first spraying channel is communicated to the space on the side of the bottom (1) away from the second bottom (2), and the other end is communicated to the oxidant cavity, one end of the second spraying channel is communicated to the space on the side of the bottom (1) away from the second bottom (2), and the other end is communicated to the fuel cavity. The spraying unit comprises a plurality of coaxial spraying units (4) and a plurality of eccentric spraying units (5), and the eccentric spraying units (5) are arranged outside the coaxial spraying units (4). The surface of the bottom (1) facing the second bottom (2) is provided with a plurality of cylindrical protrusions, and the surface of the bottom (1) away from the second bottom (2) is provided with a plurality of centrifugal grooves (6) extending into the cylindrical protrusions, the diameter of the centrifugal grooves (6) in the part of the cylindrical protrusions is greater than the diameter of the centrifugal grooves (6) in the part of the bottom (1), and the diameter of the centrifugal grooves (6) in the part of the bottom (1) is in the shape of a flared opening; the cylindrical protrusions are provided with centrifugal through holes, and the centrifugal through holes communicate the fuel cavity and the centrifugal grooves (6).
2. The 3D printing integrated injector based on eccentric injection unit according to claim 1, characterized in that: A self-supporting structure is arranged between the third bottom (3) and the second bottom (2).
3. The 3D printing integrated injector based on eccentric injection unit according to claim 1, characterized in that: The coaxial spraying unit (4) comprises a coaxial centrifugal oxygen nozzle (9) and a coaxial fuel nozzle (10), the coaxial fuel nozzle (10) is arranged outside the coaxial centrifugal oxygen nozzle (9) and connected to one end of the coaxial centrifugal oxygen nozzle (9), the coaxial centrifugal oxygen nozzle (9) is provided with a first central hole, a first annular groove is formed between the coaxial fuel nozzle (10) and the coaxial centrifugal oxygen nozzle (9), and the first central hole and one end of the first annular groove are communicated on the side of the bottom (1) away from the second bottom (2); the coaxial centrifugal oxygen nozzle (9) is provided with a first tangential hole, the first tangential hole communicates the first central hole and the oxidant cavity, the coaxial fuel nozzle (10) is provided with a first radial hole, and the first radial hole communicates the first annular groove and the fuel cavity.
4. The 3D printing integrated injector based on eccentric injection unit according to claim 3, characterized in that: The eccentric injection unit (5) comprises an eccentric centrifugal oxygen nozzle (8) and an eccentric fuel nozzle (11), the eccentric fuel nozzle (11) is arranged outside the eccentric centrifugal oxygen nozzle (8) and connected with the eccentric centrifugal oxygen nozzle (8) at one end, the eccentric centrifugal oxygen nozzle (8) is provided with a second central hole, a second annular groove is formed between the eccentric fuel nozzle (11) and the eccentric centrifugal oxygen nozzle (8), the second central hole and one end of the second annular groove are communicated on the side of the bottom (1) away from the bottom (2), the second annular groove is arranged outside the second central hole, the inner circular axis of the second annular groove deviates from the axis of the second central hole and deviates to one side of the axis of the injector body; the eccentric centrifugal oxygen nozzle (8) is provided with a second tangential hole, the second tangential hole is communicated with the oxidant cavity and the second central hole, the eccentric fuel nozzle (11) is provided with a second radial hole, and the second radial hole is communicated with the fuel cavity and the second annular groove.
5. The 3D printing integrated injector based on eccentric injection unit according to claim 4, characterized in that: The maximum width of the second annular groove is a maximum annular gap L1, the minimum width of the second annular groove is a minimum annular gap L2, the distance between the axis of the inner diameter of the second annular groove and the axis of the second central hole is an eccentric distance L3, and the eccentric distance L3=(maximum annular gap L1-minimum annular gap L2) / 2.
6. The 3D printing integrated injector based on eccentric injection unit according to claim 5, characterized in that: The width L of the first annular groove is (maximum annular gap L1+minimum annular gap L2) / 2.
7. The 3D printing integrated injector based on eccentric injection unit according to claim 6, characterized in that: The eccentric centrifugal oxygen nozzle (8) and the coaxial centrifugal oxygen nozzle (9) both comprise a plurality of tangential holes, the coaxial fuel nozzle (10) and the eccentric fuel nozzle (11) comprise a plurality of radial holes, the tangential holes, the radial holes and the centrifugal through holes are all water-drop-shaped holes, the top end part of the water-drop-shaped hole is directed to the bottom (1), and the top end angle of the water-drop-shaped hole ranges from 30 to 80 degrees; the length d of the water-drop-shaped hole of the eccentric fuel nozzle (11) along the axial direction thereof is less than 0.9L.
8. The 3D printing integrated injector based on eccentric injection unit according to claim 1, characterized in that: There are 3-6 centrifugal grooves (6) around each injection unit, and the total throttling area of the centrifugal grooves (6) accounts for 4-10% of the total throttling area of the fuel outlet.
Citation Information
Patent Citations
Prechamber injector structure
CN107939551A
Injector structure capable of preventing body from being overheated
CN114165359A