Rocket engine injector heat insulation structure and reliability checking method thereof

Abstract

The invention provides a thermal insulation structure of a rocket engine injector and a reliability assessment method thereof. The thermal insulation structure can solve the problems that the temperature of the upper surface of an injector body is too high and the use reliability is poor. The invention provides a thermal insulation structure of a rocket engine injector. The thermal insulation structure comprises an injector body, a thermal insulation structure body, a boss and an arc-shaped groove. The outlet section of the injector main body is improved into a multi-boss matched arc-shaped groove structure from a traditional solid structure, so that the thermal resistance conducted to the upstream of the injector by a high-temperature spray pipe is increased, the temperature of the upper surface of the injector main body can be reduced, the design difficulty and the production cost of upstream parts are further reduced, good mechanical resistance and high-temperature structural strength are ensured, and the service life of the injector is prolonged. The structural weight is reduced while the central flow channel is not affected, and the problems that the temperature of the upper surface of the injector body is too high and the use reliability is poor are solved.

Description

Technical Field

[0001] The present invention belongs to the field of liquid rocket engines, and in particular, relates to a rocket engine injector thermal insulation structure and a reliability assessment method thereof. Background Art

[0002] Rocket engines are used to provide spacecraft with power for orbital maneuvers and attitude adjustments. High-energy propellants flow out through the injector flow channel and burn inside the slender thin-walled nozzle to produce high-temperature and high-pressure gas, which is then ejected to generate thrust. When the engine is working, the temperature of the high-temperature and high-pressure gas can reach 2700°C, and the temperature of the outer wall of the nozzle can reach 1200-1500°C, causing the upstream injector to be at a higher temperature level. The upper temperature limit of the temperature control components on the injector is usually only 350°C, and the upper temperature limit of the valve core assembly installed on the injector is usually not higher than 80°C. The engine is connected to satellites and other spacecraft through the injector body through a docking bracket. Due to the weight constraint of the bracket, its temperature resistance is limited.

[0003] When working, rocket engines are in a drastic change of high and low temperature, high and low pressure cycle, and at the same time they need to withstand the huge vibration and impact mechanical effects brought by rocket launch. The rocket engine injector outlet section is directly connected to the high-temperature nozzle by welding, which is subjected to high temperature and high pressure. While playing a structural connection role, it must also take into account the thermal insulation capacity. In addition, in order to match the slender size of the thin-walled nozzle, the size of the injector outlet section is much smaller than the injector body, and the contact area of ​​the connection part is small, which is relatively weak in resisting mechanics. The injector outlet section also needs to have a high structural strength.

[0004] In the related prior art, a liquid rocket engine injector flange insulation structure and a liquid rocket engine (patent document CN202311787791.2) provide a liquid rocket engine injector flange insulation structure and a liquid rocket engine, wherein the insulation hole is located on the cross rib, and the cross rib is connected to the insulation block at the bottom of the injector frame; a semicircle is provided at the root of the cross rib, and the injector frame achieves insulation by increasing the thermal resistance through the cooperation of the semicircle and the insulation hole. However, since stress concentration areas are easily formed at the intersection of the cross ribs, cracks are easily generated under long-term thermal cycles, and the cross rib structure is insufficient in strength when used for heavier large-sized nozzles, this technical solution is only applicable to attitude control engines with small size and light nozzle structure.

[0005] Looking at the technical status quo at home and abroad, the connection section between the rocket engine injector and the nozzle is usually designed as a solid structure to ensure sufficient connection strength and service reliability. Moreover, the solid structure has passed decades of ground tests and in-orbit flight verifications, and has outstanding characteristics such as safety, reliability, and high structural strength. With the development of high-performance rocket engines, the temperature of the nozzle gradually increases, resulting in intensified heat conduction to the upstream injector. The temperatures of the injector body, the upstream propellant control valve, and the satellite connection bracket increase significantly, and even cause the temperatures of the temperature control components, valve spool assemblies, and brackets on the injector to exceed the safe allowable temperature range, bringing new challenges and risks to the in-orbit use of the engine. Therefore, it is urgent to optimize and improve the existing injector structure and evaluate the reliability of its use. Summary of the Invention

[0006] Aiming at the defects in the prior art, the purpose of the present invention is to provide a heat insulation structure for a rocket engine injector and a method for evaluating its reliability.

[0007] A heat insulation structure for a rocket engine injector according to the present invention includes: an injector body, a heat insulation structure body, a boss, and a flow channel hole;

[0008] The heat insulation structure body is arranged at the outlet section of the injector body; a plurality of uniformly distributed bosses are arranged on the outer peripheral side of the heat insulation structure body; and a flow channel hole is arranged inside the injector body.

[0009] Preferably, the heat insulation structure for a rocket engine injector further includes: an arc-shaped groove and a nozzle; arc-shaped grooves are uniformly arranged between the bosses; and the outlet port of the injector body and the nozzle are welded into an integral body by a high-energy beam.

[0010] Preferably, the bottom of the arc-shaped groove is far from the flow channel hole, the distance from the bottom of the arc-shaped groove to the flow channel hole is not less than 5 mm, and the ratio of the depth to the width of the arc-shaped groove is 0.3 to 0.5.

[0011] Preferably, the outer contour of the outlet section of the injector body is cylindrical, and the diameter is 30 mm to 80 mm.

[0012] Preferably, the distance from the end of the heat insulation structure body to the outlet end of the injector body is not less than 5 mm.

[0013] Preferably, the width of the boss is 5 mm to 10 mm; the ratio of the width of the boss to the spacing between adjacent bosses is not greater than 0.3.

[0014] Preferably, the number of the bosses and the arc-shaped grooves is the same, and both are not less than four.

[0015] Preferably, the material of the injector body is titanium alloy.

[0016] Preferably, the outer contour of the outlet section of the injector body is cylindrical with a diameter of 70 mm; the width of the boss is 6 mm; the number of the bosses and the arc-shaped grooves is the same, both being six; the distance from the bottom of the arc-shaped groove to the flow passage hole is 15 mm; the material of the injector body is titanium alloy with the grade of 7715D or TC4.

[0017] A reliability assessment method for the heat insulation structure of a rocket engine injector provided by the present invention includes:

[0018] Step S1: Design and process the heat insulation structure of the rocket engine injector provided by the present invention according to the mission requirements.

[0019] Step S2: Weld the injector body and the nozzle by high-energy beam welding, and assess the thermal influence of the high-energy beam welding on the overall structure. After welding, the structure is not allowed to have deformation or damage.

[0020] Step S3: Conduct a strength test under the rocket engine condition, and assess the rocket engine injector heat insulation structure for a set time under a set multiple of the working pressure. The structure is not allowed to have deformation or damage.

[0021] Step S4: Conduct vibration and shock mechanics tests under the rocket engine condition, and conduct qualification-level vibration and shock tests on the rocket engine injector heat insulation structure. The structure is not allowed to have deformation or damage.

[0022] Step S5: Conduct a high-altitude simulation hot test under the rocket engine condition, and conduct high-temperature, high-pressure and structural assessments on the rocket engine injector heat insulation structure under real high-altitude simulation working conditions. If the rocket engine injector heat insulation structure does not undergo deformation or damage after the test run, it is considered that the design of the rocket engine injector heat insulation structure is reasonable.

[0023] If the rocket engine injector heat insulation structure undergoes deformation or damage in any step, it is necessary to return to Step S1 and re-design and process.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] 1. The present invention improves the outlet section of the injector from the traditional solid structure to a multi-boss arc-shaped groove structure, which increases the thermal resistance of the high-temperature nozzle conducting heat to the upstream of the injector, and ensures good anti-mechanical and high-temperature structural strength. It can reduce the temperature of the upstream components, thereby reducing the design difficulty and production cost of the upstream components.

[0026] 2. Through structural design, the present invention reduces the structural weight without affecting the central flow channel; eliminates stress concentration points, evenly distributes stress, can reduce thermal deformation stress, forms an annular symmetric support with multiple bosses distributed, reduces local loads, improves fatigue resistance, has the ability of self-adaptive thermal deformation, and balances structural strength and heat insulation.

[0027] 3. The present invention can effectively evaluate the service reliability of the heat insulation structure of the injector, ensuring the flight safety of the spacecraft;

[0028] 4. The structure of the present invention optimizes the heat flow distribution by improving the ratio of the boss width to the spacing, achieving a decrease in the temperature gradient; ensures the balance of structural stiffness and heat insulation performance by setting a reasonable ratio of the depth to the width of the arc-shaped groove. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Other features, objects, and advantages of the present invention will become more apparent by reading the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0030] Figure 1 It is a schematic overall sectional view of a heat insulation structure of a rocket engine injector according to the present invention.

[0031] Figure 2 is Figure 1 An enlarged view of the cross-section B-B in

[0032] Figure 3 It is a schematic assembly view of the present invention applied to a rocket engine.

[0033] As shown in the figure:

[0034] DETAILED DESCRIPTION OF THE EMBODIMENTS

[0035] The present invention will be described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but do not limit the present invention in any form. It should be noted that those of ordinary skill in the art can make several changes and improvements without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0036] As Figures 1 to 3 shown, an embodiment of the present invention provides a heat insulation structure of a rocket engine injector, including: an injector main body 1, a heat insulation structure main body 2, bosses 3, and flow channel holes 5; the heat insulation structure main body 2 is arranged at the outlet section of the injector main body 1, a plurality of evenly distributed bosses 3 are arranged on the outer peripheral side of the heat insulation structure main body 2, and flow channel holes 5 are arranged inside the injector main body 1.

[0037] The heat insulation structure of the rocket engine injector further includes: an arc-shaped groove 4 and a nozzle 6; arc-shaped grooves 4 are evenly arranged between the bosses 3; the bottom of the arc-shaped groove 4 is far from the flow channel hole 5; the outlet port of the injector body 1 and the nozzle 6 are integrally welded by a high-energy beam.

[0038] Further, the outer contour of the outlet section of the injector body 1 is cylindrical, with a diameter ranging from 30 mm to 80 mm; if the diameter is too small, the structural strength will be insufficient after adding the heat insulation structure body 2; if the diameter is too large, the heat capacity of the injector body 1 itself is relatively large, and the heat insulation effect after adding the heat insulation structure body 2 is not obvious; the distance from the end of the heat insulation structure body 2 to the outlet end of the injector body 1 is not less than 5 mm; if the distance is too small, the heat insulation structure body 2 will be affected by the heat of the high-energy beam welding, resulting in deformation; the width of the boss 3 is 5 mm to 10 mm, which can take into account good processability and heat insulation performance; the number of bosses 3 and the arc-shaped grooves 4 is the same, and both are not less than four; the distance from the bottom of the arc-shaped groove 4 to the flow channel hole 5 is not less than 5 mm to ensure that the heat insulation structure body 2 does not affect the flow of the propellant in the central flow channel. Further, the ratio of the width of the boss 3 to the distance between adjacent bosses 3 is not greater than 0.3; the ratio of the depth to the width of the arc-shaped groove 4 is 0.3 - 0.5; setting a reasonable ratio of the width of the boss 3 to the distance optimizes the heat flow distribution and realizes a decrease in the temperature gradient; setting a reasonable ratio of the depth to the width of the arc-shaped groove 4 ensures the balance between the structural stiffness and the heat insulation performance.

[0039] The material of the injector body 1 is titanium alloy, with the grade of 7715D or TC4. Both 7715D and TC4 are high-temperature and high-strength titanium alloy materials, having good mechanical strength performance and can be applied to the injector of the space attitude and orbit control liquid rocket engine.

[0040] Further, the present invention also provides a more specific implementation manner. The outer contour of the outlet section of the injector body 1 is cylindrical, with a diameter of 70 mm; the width of the boss 3 is 6 mm; the number of bosses 3 and the arc-shaped grooves 4 is the same, both being six; the distance from the bottom of the arc-shaped groove 4 to the flow channel hole 5 is 15 mm; the material of the injector body 1 is titanium alloy, with the grade of 7715D or TC4.

[0041] In a more specific embodiment, the width of the boss 3 is 6 mm, the distance between two adjacent bosses 3 is 29.2 mm, and the ratio of the width of the boss 3 to the distance between two adjacent bosses 3 is 0.21; the depth of the arc-shaped groove 4 is 10.7 mm, the width is 29.2 mm, and the depth-width ratio is 0.37.

[0042] Further, the embodiment of the present invention also provides a reliability assessment method for the heat insulation structure of the rocket engine injector described in the present invention; including:

[0043] Step S1: designing and processing a rocket engine injector thermal insulation structure according to the task requirements;

[0044] Step S2: using high-energy beam welding to weld the injector body 1 and the nozzle 6, and examining the thermal effect of high-energy beam welding on the overall structure. After welding, the structure is not allowed to be deformed or damaged;

[0045] Step S3: Conduct a strength test on the rocket engine state, and test the rocket engine injector insulation structure at 2 times the working pressure for 5 minutes or more. The structure is not allowed to be deformed or damaged;

[0046] Step S4: Conduct vibration and impact mechanical tests on the rocket engine state, and conduct identification-level vibration and impact test assessments on the rocket engine injector insulation structure. The structure is not allowed to be deformed or damaged;

[0047] Step S5: The rocket engine is in a state of conducting a high-altitude simulated thermal test, and the rocket engine injector insulation structure is subjected to high temperature, high pressure and structural assessment under real high-altitude simulated working conditions. If the rocket engine injector insulation structure has not been deformed or damaged after the test, it is considered that the rocket engine injector insulation structure is reasonably designed.

[0048] If the rocket engine injector thermal insulation structure is deformed or damaged in any step, it is necessary to return to step S1 and redesign it.

[0049] In summary, the embodiment of the present invention provides a rocket engine injector heat insulation structure and reliability assessment method thereof, which can solve the problem of excessively high temperature on the upper surface of the injector body and reliability in use; the outlet section of the injector body 1 is improved from the traditional solid structure to a structure with multiple bosses 3 and arc grooves 4, which increases the thermal resistance of the high-temperature nozzle to the upstream of the injector, and can reduce the upper surface temperature of the injector body, thereby reducing the design difficulty and production cost of the upstream components; the special design of the arc groove 4 replaces the traditional right-angle intersection, eliminates the stress concentration point, and is matched with the arc-shaped overall structure to evenly distribute the thermal stress and reduce the thermal deformation stress; the distribution of multiple bosses 3 further forms an annular symmetrical support, reduces the local load, and improves the fatigue resistance, so that the overall structure has the ability of adaptive thermal deformation, and balances the structural strength and thermal insulation. Overall, it ensures good mechanical resistance and high-temperature structural strength, reduces the structural weight without affecting the central flow channel, and solves the problem of excessively high temperature on the upper surface of the injector body and reliability in use.

[0050] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present application.

[0051] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which does not affect the essence of the present invention. Without conflict, the embodiments of the present application and the features in the embodiments can be combined with each other arbitrarily.

Claims

1. A heat insulation structure for a rocket engine injector, characterized in that, Including: Injector body (1), heat insulation structure body (2), boss (3), flow channel hole (5); The heat insulation structure body (2) is arranged at the outlet section of the injector body (1); A plurality of uniformly distributed bosses (3) are arranged on the outer peripheral side of the heat insulation structure body (2); A flow channel hole (5) is arranged inside the injector body (1).

2. The heat insulation structure of the rocket engine injector according to claim 1, wherein, Also including: Arc-shaped groove (4), nozzle (6); Arc-shaped grooves (4) are uniformly arranged between the bosses (3); The outlet port of the injector body (1) and the nozzle (6) are welded into a whole by high-energy beam welding.

3. The heat insulation structure of the rocket engine injector according to claim 2, characterized in that, The bottom of the arc-shaped groove (4) is far from the flow channel hole (5), the distance from the bottom of the arc-shaped groove (4) to the flow channel hole (5) is not less than 5 mm, and the ratio of the depth to the width of the arc-shaped groove (4) is 0.3 to 0.

5.

4. The heat insulation structure of the rocket engine injector according to claim 1, wherein The outer contour of the outlet section of the injector body (1) is cylindrical, with a diameter of 30 mm to 80 mm.

5. The heat insulation structure of the rocket engine injector according to claim 1, wherein, The distance from the end of the heat insulation structure body (2) to the outlet end of the injector body (1) is not less than 5 mm.

6. The heat insulation structure of the rocket engine injector according to claim 1, characterized in that, The width of the boss (3) is 5 mm to 10 mm; the ratio of the width of the boss (3) to the spacing between adjacent bosses (3) is not greater than 0.

3.

7. The heat insulation structure of a rocket engine injector according to claim 2, characterized in that, The number of the bosses (3) is the same as that of the arc-shaped grooves (4), and both are not less than four.

8. The heat insulation structure of the rocket engine injector according to claim 1, wherein, The material of the injector body (1) is titanium alloy.

9. The heat insulation structure of the rocket engine injector according to any one of claims 1 to 8, characterized in that The outer contour of the outlet section of the injector body (1) is cylindrical, with a diameter of 70 mm; the width of the boss (3) is 6 mm; the number of the bosses (3) is the same as that of the arc-shaped grooves (4), both are six; the distance from the bottom of the arc-shaped groove (4) to the flow channel hole (5) is 15 mm; the material of the injector body (1) is titanium alloy, and the grade is 7715D or TC4.

10. A reliability assessment method for the heat insulation structure of a rocket engine injector, characterized in that, Including: Step S1: Design and process the rocket engine injector heat insulation structure according to any one of claims 1 to 9 according to the task requirements; Step S2: Weld the injector body (1) and the nozzle (6) by high-energy beam welding, and examine the thermal influence of the high-energy beam welding on the overall structure. After welding, the structure is not allowed to be deformed or damaged; Step S3: Carry out a strength test in the state of the rocket engine, and examine the rocket engine injector heat insulation structure for a set time under a set multiple of the working pressure. The structure is not allowed to be deformed or damaged; Step S4: Carry out vibration and shock mechanics tests in the state of the rocket engine, and conduct qualification-level vibration and shock tests on the rocket engine injector heat insulation structure. The structure is not allowed to be deformed or damaged; Step S5: Carry out a high-altitude simulation hot test in the state of the rocket engine, and conduct high-temperature, high-pressure and structural examinations on the rocket engine injector heat insulation structure under real high-altitude simulation working conditions. If the rocket engine injector heat insulation structure does not deform or break after the test run, it is considered that the design of the rocket engine injector heat insulation structure is reasonable; If the rocket engine injector heat insulation structure is deformed or damaged in any step, it is necessary to return to step S1 and re-design and process.

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