Reliable sealing structure for isolating bipropellant hypergolic propellants

Abstract

The present invention provides a reliable sealing structure for isolating bicomponent hypergolic propellants, including an injector frame, an injector core, an oxidizer support and a fuel support. The injector frame is provided with a fuel inner hole and an oxidizer inner hole, and the injector core is arranged in the oxidizer inner hole; the injector core is provided with an oxidizer injection hole and a fuel injection hole arranged obliquely to each other, and the distance between the top ends of the two is greater than the distance between the bottom ends of the two; the oxidizer support is arranged in the inner hole of the injector core and communicated with the top end of the oxidizer injection hole to form an oxidizer path flow channel, and the fuel support is arranged in the fuel inner hole and communicated with the top end of the fuel injection hole to form a fuel path flow channel. In the present invention, the oxidizer injection hole and the fuel injection hole are arranged obliquely to each other, completely isolating the contact between the two paths of hypergolic propellants, changing the previous design of relying on welds for sealing, and even if there is a leak at the weld in the present structure, the propellant will not explode due to cross-cavity contact in the flow channel.

Description

Technical Field

[0001] The invention relates to the technical field of liquid rocket engines, and in particular to a reliable sealing structure for isolating bicomponent hypergolic propellants. Background Art

[0002] Space liquid rocket engines provide power for orbit transfer and attitude control for spacecraft. They widely use a combination of bicomponent hypergolic propellants, such as nitrogen tetroxide as the oxidizer and monomethyl hydrazine, anhydrous hydrazine, unsymmetrical dimethyl hydrazine or mixed hydrazine as the fuel, which are all highly toxic and corrosive. The oxidizer and fuel flow through two propellant control valves and the internal flow channel of the engine respectively, and then are injected and burned in the combustion chamber. Once the propellant contacts the cavity in the internal flow channel, it will explode, which directly affects the safety of the spacecraft. With the continuous increase in the service life of spacecraft in orbit, for example, the space station built by my country is required to have a service life of more than 15 years in orbit. During the period of orbit, the engine needs to be ignited multiple times according to the flight strategy. The sealing stability of the propellant in the internal flow channel of the engine and the reliability during the long life working cycle become particularly important. Once the seal fails, it will cause serious damage to the safety of the spacecraft in orbit.

[0003] Looking at the current state of technology at home and abroad, the sealing structure of a space bipropellant liquid rocket engine generally uses diffusion brazing or high-energy beam welding to isolate the oxidant and fuel channels. Diffusion brazing requires filling brazing material between the butted parts, which has high requirements for the processing state of the butt surfaces of the parts. High-energy beam welding has high energy density and is prone to welding deformation in areas with smaller structural dimensions, which increases the difficulty of effective weld formation. Moreover, once the weld cracks, there is a huge risk of explosion between the two propellants. Once the self-igniting propellants come into contact and burn, a large instantaneous pressure is generated in the narrow internal channel, which will directly lead to further damage to the weld structure until an explosion occurs.

[0004] The patent document with the publication number CN107178437A discloses a micro gas-gas bipropellant burner, including a body, etc.; the nozzle is installed in the body, the nozzle is welded on the body, the lower end face of the nozzle is close to the upper end face of the nozzle, the fuel inlet is welded on the nozzle, the oxidant inlet is welded on the body, the nozzle and the body are connected by threads, and the nozzle and the body are sealed by a sealing ring; the body and the nozzle constitute an annular gas collecting cavity, the nozzle and the nozzle constitute a premixing cavity, the body is provided with a combustion chamber and a nozzle, the nozzle is provided with a contraction flow channel, and the nozzle is provided with a fuel injection hole and an oxidant injection hole; the gaseous fuel enters the premixing cavity through the fuel inlet and the fuel injection hole. The invention takes into account both reliable ignition and stable combustion functions. However, the invention isolates the oxidant and fuel flow channels by welds, and cannot achieve reliable sealing of the oxidant and fuel flow channels in a small space. Summary of the invention

[0005] In view of the defects in the prior art, an object of the present invention is to provide a reliable sealing structure for isolating bipropellant hypergolic propellant.

[0006] According to the reliable sealing structure for isolating bipropellant provided by the present invention, the reliable sealing structure for isolating bipropellant is characterized in that it comprises an injector frame, an injector core, an oxidant support and a fuel support, the injector frame is provided with a fuel inner hole and an oxidant inner hole, and the injector core is arranged in the oxidant inner hole;

[0007] The injection core is provided with an oxidant injection hole and a fuel injection hole which are arranged obliquely to each other, and the distance between the top ends of the two is greater than the distance between the bottom ends of the two;

[0008] The oxidant support is arranged in the inner hole of the injection core and is connected to the top of the oxidant injection hole to form an oxidant path flow channel. The fuel support is arranged in the fuel inner hole and is connected to the top of the fuel injection hole to form a fuel path flow channel.

[0009] Preferably, the injection core is provided with a plurality of pairs of oxidant injection holes and fuel injection holes, the oxidant support is connected with the plurality of oxidant injection holes, and the fuel support is arranged in one-to-one correspondence with the fuel injection holes.

[0010] Preferably, the injector frame, injector core, oxidant support and fuel support are all made of titanium alloy or high-temperature alloy.

[0011] Preferably, the inner hole of the oxidant is recessed outward at the connection point between the fuel support and the fuel injection hole to form an annular liquid collecting cavity, and the fuel support, the annular liquid collecting cavity and the fuel injection hole are connected in sequence to form a fuel path flow channel.

[0012] Preferably, both the oxidizer support and the fuel support are provided with propellant control valves.

[0013] Preferably, the tops of the oxidizer support and the fuel support are both recessed downward to form a valve installation position, and the bottom end of the propellant control valve is arranged in the valve installation position;

[0014] A support annular mounting groove is provided at the bottom of the valve mounting position, a sealing gasket is provided in the support annular mounting groove, an O-ring mounting groove is provided on the outer side of the bottom end of the propellant control valve, and an O-ring is provided in the O-ring mounting groove.

[0015] Preferably, the difference between the inner diameter of the annular mounting groove of the support and the diameter of the oxidant path flow channel or the fuel path flow channel is not less than 2 mm;

[0016] The depth of the support annular mounting groove is greater than the thickness of the sealing gasket.

[0017] Preferably, the tops of the oxidant support and the fuel support are both recessed downward to form a valve mounting position, and the bottom of the valve mounting position is recessed downward to form a conical support spherical groove;

[0018] The bottom end of the propellant control valve is located in the valve installation position, the bottom end of the propellant control valve is provided with a docking ball head, the docking ball head is arranged in the spherical groove of the support, the outer side of the bottom end of the propellant control valve is provided with an O-ring installation groove, and an O-ring is arranged in the O-ring installation groove.

[0019] Preferably, the roughness of the sealing surface of the docking ball head is not greater than 3.2, and the spherical angle of the docking ball head is 20° to 40°.

[0020] Preferably, the lower end surface of the injector frame and the lower end surface of the injector core are located in the same plane, the diameter of the inner hole of the oxidant is Ф10-50mm, the diameter of the inner hole of the injector core is Ф5-30mm, and the diameter of the inner hole of the fuel is Ф5-30mm.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. The present invention has a simple structure and is easy to operate. By adopting the technical means of arranging the oxidant injection hole and the fuel injection hole in an inclined manner with respect to each other, the contact between the two self-igniting propellants is completely isolated, which changes the previous design of relying on welds for sealing. Moreover, even if leakage occurs at the welds in the present structure, the propellants will not cross-cavity contact in the flow channel and explode.

[0023] 2. The present invention adopts the technical means of multi-component combination molding, which is conducive to the inspection and cleaning of excess materials and burrs on the orifices of multiple injection holes during the production and processing.

[0024] 3. The present invention adopts a double-pass sealing technology between the oxidizer support, the fuel support and the propellant control valve to ensure a long-term reliable seal with the highly corrosive propellant. The docking ball head is set in the spherical groove of the support to effectively avoid direct contact between the O-ring rubber seal and the propellant, making it more suitable for long-life spacecraft. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments made with reference to the following drawings:

[0026] Figure 1 This is a schematic diagram of the structure when the present invention adopts a support annular mounting groove;

[0027] Figure 2This is a schematic diagram of the connection between the support annular mounting groove and the propellant control valve when the present invention adopts the support annular mounting groove;

[0028] Figure 3 This is a schematic diagram of the structure when the present invention uses a support spherical groove;

[0029] Figure 4 This is a schematic diagram of the connection between the support spherical groove and the propellant control valve when the present invention adopts the support spherical groove.

[0030] The figure shows:

[0031] Injector frame 1 Annular liquid collecting chamber 5

[0032] Injection core 2 Sealing gasket 6

[0033] Oxidizer support 3 Propellant control valve 7

[0034] Support annular mounting groove 31 O-ring mounting groove 71

[0035] Support spherical groove 32 Docking ball head 72

[0036] Fuel support 4 O-ring 8 DETAILED DESCRIPTION

[0037] The present invention is 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 are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several changes and improvements can also be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0038] The present invention discloses a reliable sealing structure for isolating a dual-component hypergolic propellant, which can achieve effective isolation of oxidant and fuel flow channels from a structural perspective, rather than relying on welds that mainly play a connecting role, and can effectively prevent hypergolic propellant from exploding in a cavity in contact with each other. Even if the weld cracks, the propellant can only leak into an external low-pressure environment, and the two hypergolic propellants will not directly contact and burn in a narrow flow channel, generating instantaneous high pressure locally and causing further damage to the structure, thereby endangering the flight safety of the spacecraft.

[0039] According to the reliable sealing structure of the isolated bipropellant provided by the present invention, Figure 1-4As shown, it includes an injector frame 1, an injector core 2, an oxidant support 3 and a fuel support 4. The injector frame 1 is provided with a fuel inner hole and an oxidant inner hole, and the injector core 2 is arranged in the oxidant inner hole; the injector core 2 is provided with an oxidant injection hole and a fuel injection hole arranged obliquely to each other, and the distance between the top ends of the two is greater than the distance between the bottom ends of the two, so as to achieve effective isolation of the oxidant and fuel flow channels, the oxidant support 3 is arranged in the inner hole of the injector core 2 and communicated with the top end of the oxidant injection hole to form an oxidant flow channel, and the fuel support 4 is arranged in the fuel inner hole and communicated with the top end of the fuel injection hole to form a fuel flow channel. Preferably, the connection between the injector frame 1, the injector core 2, the oxidant support 3 and the fuel support 4 is achieved by brazing or high-energy beam welding.

[0040] Preferably, the lower end surface of the injector frame 1 and the lower end surface of the injector core 2 are located in the same plane, the diameter of the inner hole of the oxidant is Ф10-50mm, the diameter of the inner hole of the injector core 2 is Ф5-30mm, and the diameter of the inner hole of the fuel is Ф5-30mm.

[0041] The injection core 2 is provided with a plurality of pairs of oxidant injection holes and fuel injection holes, the oxidant support 3 is connected with the plurality of oxidant injection holes, and the fuel support 4 is arranged one by one with the fuel injection holes. The injector frame 1, the injection core 2, the oxidant support 3 and the fuel support 4 are all made of titanium alloy or high-temperature alloy. The oxidant inner hole is recessed outward at the connection between the fuel support 4 and the fuel injection hole to form an annular liquid collecting cavity 5, and the fuel support 4, the annular liquid collecting cavity 5 and the fuel injection hole are connected in sequence to form a fuel path flow channel.

[0042] The oxidant support 3 and the fuel support 4 are both provided with a propellant control valve 7 .

[0043] like Figure 1 , 2 As shown, the tops of the oxidant support 3 and the fuel support 4 are both recessed downward to form a valve installation position, and the bottom end of the propellant control valve 7 is arranged in the valve installation position; the bottom of the valve installation position is provided with a support annular installation groove 31, and a sealing gasket 6 is arranged in the support annular installation groove 31, and an O-type sealing ring installation groove 71 is arranged on the outer side of the bottom end of the propellant control valve 7, and an O-type sealing ring 8 is arranged in the O-type sealing ring installation groove 71. The difference between the inner diameter of the support annular installation groove 31 and the diameter of the oxidant path flow channel or the fuel path flow channel is not less than 2mm; the depth of the support annular installation groove 31 is greater than the thickness of the sealing gasket 6.

[0044] The sealing gasket 6 and the O-ring 8 form a first sealing structure. The method for realizing double-pass sealing of the first sealing structure is that the sealing gasket 6 is placed in the annular mounting groove 31 of the support, and is squeezed and deformed under the action of the installation torque, and is embedded in the annular mounting groove 31 of the support to realize the first seal; the O-ring 8 is radially placed in the O-ring mounting groove 71 at the bottom end of the propellant control valve docking column to realize the second seal. Preferably, the material of the sealing gasket 6 is fluoroplastic with a thickness of 2mm to 4mm. The material of the O-ring 8 is fluoroether rubber.

[0045] or, as Figure 3 , 4 As shown, the tops of the oxidizer support 3 and the fuel support 4 are both recessed downward to form a valve installation position, and the bottom of the valve installation position is recessed downward to form a conical support spherical groove 32; the bottom end of the propellant control valve 7 is located in the valve installation position, and the bottom end of the propellant control valve 7 is provided with a docking ball head 72, and the docking ball head 72 is arranged in the support spherical groove 32, and the outer side of the bottom end of the propellant control valve 7 is provided with an O-type sealing ring installation groove 71, and the O-type sealing ring 8 is arranged in the O-type sealing ring installation groove 71. The roughness of the sealing surface of the docking ball head 72 is not greater than 3.2, and the spherical angle of the docking ball head 72 is 20° to 40°.

[0046] The docking ball head 72 and the O-ring 8 form a second sealing structure. The method for realizing double-pass sealing of the second sealing structure is that a hard sealing pair is formed between the docking ball head 72 of the propellant control valve 7 and the support spherical groove 32 of the oxidizer support 3 or the fuel support 4 to realize the first pass of sealing; the O-ring 8 is placed in the O-ring installation groove 71 above the docking ball head to realize the second pass of sealing.

[0047] Example 1

[0048] In this embodiment, the oxidant support 3 and the fuel support 4 are connected to the propellant control valve 7 through the first sealing structure, the inner diameter of the support annular mounting groove 31 and the sealing gasket 6 are both Φ5mm, the outer diameter is both Φ9mm, the diameter of the oxidant path flow channel or the fuel path flow channel is both Φ3mm; the depth of the support annular mounting groove 31 is 2.5mm; the material of the sealing gasket 6 is polytetrafluoroethylene propylene fluoroplastic, with a thickness of 2mm. The material of the O-ring 8 is perfluoroether rubber.

[0049] Example 2

[0050] In this embodiment, the oxidizer support 3 and the fuel support 4 are connected to the propellant control valve 7 via a second sealing structure, the sealing surface roughness of the docking ball head 72 is 1.6, and the spherical angle of the docking ball head 72 is 24°.

[0051] The present invention has strong expansibility and is applicable to the structural design of liquid rocket engines of different small and medium thrust sizes in various fields such as spacecraft, satellites, deep space exploration, weapons, and launch vehicles, and has the beneficial effects of good sealing stability and long service life.

[0052] In the description of the present application, it should be understood that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0053] The above describes the specific embodiments of the present invention. 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. In the absence of conflict, the embodiments of the present application and the features in the embodiments can be combined with each other arbitrarily.

Claims

1. A reliable sealing structure for isolating bipropellant hypergolic propellant, characterized in that: It comprises an injector frame (1), an injector core (2), an oxidant support (3) and a fuel support (4); the injector frame (1) is provided with a fuel inner hole and an oxidant inner hole, and the injector core (2) is arranged in the oxidant inner hole; The injection core (2) is provided with an oxidant injection hole and a fuel injection hole which are arranged obliquely to each other, and the distance between the top ends of the two is greater than the distance between the bottom ends of the two; The oxidant support (3) is arranged in the inner hole of the injection core (2) and is connected to the top of the oxidant injection hole to form an oxidant flow channel, and the fuel support (4) is arranged in the inner hole of the fuel and is connected to the top of the fuel injection hole to form a fuel flow channel; The oxidant support (3) and the fuel support (4) are both provided with a propellant control valve (7); The tops of the oxidant support (3) and the fuel support (4) are both recessed downward to form a valve installation position, and the bottom end of the propellant control valve (7) is arranged in the valve installation position; A support annular mounting groove (31) is provided at the bottom of the valve mounting position, a sealing gasket (6) is provided in the support annular mounting groove (31), an O-ring mounting groove (71) is provided on the outer side of the bottom end of the propellant control valve (7), an O-ring mounting groove (71) is provided in the O-ring mounting groove (71); an O-ring (8) is provided in the O-ring mounting groove (71); The tops of the oxidant support (3) and the fuel support (4) are both recessed downward to form a valve installation position, and the bottom of the valve installation position is recessed downward to form a conical support spherical groove (32); The bottom end of the propellant control valve (7) is located in the valve installation position. The bottom end of the propellant control valve (7) is provided with a docking ball head (72), and the docking ball head (72) is arranged in the support spherical groove (32). The outside of the bottom end of the propellant control valve (7) is provided with an O-type sealing ring installation groove (71), and an O-type sealing ring (8) is arranged in the O-type sealing ring installation groove (71).

2. The reliable sealing structure for isolating bipropellant hypergolic propellant according to claim 1, characterized in that: The injection core (2) is provided with a plurality of pairs of oxidant injection holes and fuel injection holes, the oxidant support (3) is connected to the plurality of oxidant injection holes, and the fuel support (4) is arranged in one-to-one correspondence with the fuel injection holes.

3. The reliable sealing structure for isolating bipropellant hypergolic propellant according to claim 1, characterized in that: The injector frame (1), the injector core (2), the oxidant support (3) and the fuel support (4) are all made of titanium alloy or high-temperature alloy.

4. The reliable sealing structure for isolating bipropellant hypergolic propellant according to claim 1, characterized in that: The inner hole of the oxidant is recessed outward at the connection point between the fuel support (4) and the fuel injection hole to form an annular liquid collecting cavity (5); the fuel support (4), the annular liquid collecting cavity (5) and the fuel injection hole are connected in sequence to form a fuel path flow channel.

5. The reliable sealing structure for isolating bipropellant hypergolic propellant according to claim 1, characterized in that: The difference between the inner diameter of the support annular mounting groove (31) and the diameter of the oxidant path flow channel or the fuel path flow channel is not less than 2 mm; The depth of the support annular mounting groove (31) is greater than the thickness of the sealing gasket (6).

6. The reliable sealing structure for isolating bipropellant hypergolic propellant according to claim 1, characterized in that: The roughness of the sealing surface of the docking ball head (72) is not greater than 3.2, and the spherical angle of the docking ball head (72) is 20° to 40°.

7. The reliable sealing structure for isolating bipropellant hypergolic propellant according to claim 1, characterized in that: The lower end surface of the injector frame (1) and the lower end surface of the injector core (2) are located in the same plane, the diameter of the inner hole of the oxidant is Φ10-50 mm, the diameter of the inner hole of the injector core (2) is Φ5-30 mm, and the diameter of the inner hole of the fuel is Φ5-30 mm.

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