Secondary gunpowder starter

Abstract

The secondary gunpowder starter comprises a main shell and a spray pipe seat, the main shell and the spray pipe seat are connected through a flange structure, and a combustion chamber is formed in the main shell and the spray pipe seat; the flange structure comprises a first flange arranged on the end face of the main shell and a second flange arranged on the end face of the spray pipe base, and the first flange and the second flange are fixed through fastening bolts. The increase of the internal temperature of the gunpowder starter is controlled through the modes that water in the annular cavity of the spray pipe seat is vaporized to take away heat and radiative heat transfer is carried out between the main shell and the flange structure of the spray pipe seat. The technical problem that high-temperature and high-pressure fuel gas cannot be isolated, so that a secondary gunpowder starter burns earlier than a preset time in the first starting and working process of a liquid rocket engine is solved, and the technical problems that in an existing secondary starting gunpowder starter, a heat insulation structure is complex in manufacturing and mounting process, the falling probability is high, and the service life is long are solved. And the starter is high in cost and low in reliability.

Description

Technical Field

[0001] The invention belongs to the technical field of liquid rocket engines and relates to a gunpowder starter, in particular to a secondary gunpowder starter. Background Art

[0002] The secondary start of a liquid rocket engine is one of the key technologies for recoverable liquid launch vehicles. The current technical approach is that a liquid rocket engine is equipped with two gunpowder starters, which are used for the primary start and secondary start of the engine respectively. The two gunpowder starters are physically installed in parallel and work in series in terms of timing. When the gunpowder starter used for the primary start of the liquid rocket engine is working and during the operation of the liquid rocket engine, high-temperature and high-pressure combustion gases are generated, and these high-temperature and high-pressure combustion gases are applied to the secondary gunpowder starter used for the engine throughout the process.

[0003] In order to ensure that the secondary propellant starter can withstand the above-mentioned harsh gas environment and reliably ignite itself, it is necessary to design an isolation device and take insulation measures. The Chinese invention patent with the authorization announcement number CN 114439648 B discloses a secondary propellant starter suitable for an engine. The invention partially isolates the external high-temperature gas from being transmitted to the main shell through the nozzle seat by setting an insulation pad between the flange of the main shell and the nozzle seat; the first insulation layer and the second insulation layer are respectively set on the inner wall of the main shell and the nozzle seat, ensuring that the temperature inside the shell is below the combustible temperature of the propellant column. The above measures can achieve effective heat isolation, but there are the following problems: First, the cost is high. Since the thermal insulation pad, the first thermal insulation layer and the second thermal insulation layer are made of high-temperature resistant materials, the manufacturing and installation processes are complicated, resulting in high costs and poor economic affordability. Second, the first thermal insulation layer and the second thermal insulation layer are bonded to the inner wall of the main shell and the nozzle seat with adhesives. The quality of the adhesive itself and the quality of the coating construction will affect the bonding quality of the thermal insulation layer with the shell and the nozzle seat. The probability of the first thermal insulation layer and the second thermal insulation layer falling off is relatively high. Once the thermal insulation layer falls off, it will lose its thermal insulation function, thereby affecting the reliability of the thermal insulation. Summary of the invention

[0004] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a secondary gunpowder starter to solve the technical problems of the existing secondary starting gunpowder starter, such as the complicated manufacturing and installation process of the insulation structure and the high probability of falling off, which leads to high starter cost and low reliability.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions to achieve the above problems:

[0006] A secondary powder starter comprises a main shell and a nozzle seat, wherein the main shell and the nozzle seat are connected via a flange structure and a combustion chamber is formed inside the main shell and the nozzle seat;

[0007] The flange structure includes a first flange provided on the end face of the main housing and a second flange provided on the end face of the nozzle seat. The first flange and the second flange are fixed by fastening bolts. There is a gap between the first flange and the second flange, and a mating groove and tenon are respectively provided on their end faces. A second sealing ring is also provided between the tenon and the groove.

[0008] An electric igniter is provided at the axial front end of the main housing. An ignition bracket and a medicine baffle are sequentially arranged along the axial direction in the combustion chamber. The ignition bracket and the medicine baffle divide the combustion chamber into a first cavity, a second cavity, and a third cavity. An ignition cartridge is provided in the first cavity, and a main charge is provided in the second cavity.

[0009] The nozzle seat includes a nozzle seat outer shell and a nozzle seat inner conical shell. An annular cavity is formed between the nozzle seat outer shell and the nozzle seat inner conical shell, and water is provided in the annular cavity. A vent hole is provided on the nozzle seat outer shell, and a rubber plug is provided in the vent hole. A nozzle with one end communicating with the third cavity is provided in the nozzle seat. The other end of the nozzle is provided with a gas diaphragm assembly fixed on the inner wall of the nozzle seat. A nozzle seat outlet flange is provided at the axial rear end of the nozzle seat.

[0010] The present invention further includes the following technical features:

[0011] The rubber plug is frustum-shaped, and the end face with a smaller diameter is close to the annular cavity.

[0012] A first sealing ring is provided between the main housing and the electric igniter.

[0013] A buffer pad is provided between the ignition bracket and the main charge.

[0014] An elastic pad is provided between the main charge and the medicine baffle.

[0015] The gas diaphragm assembly includes a baffle and a diaphragm arranged sequentially along the axial direction.

[0016] On one side of the diaphragm close to the outlet of the nozzle seat, there are engraved "cross" - shaped marks.

[0017] Both the baffle and the diaphragm are "concave" - shaped.

[0018] A plurality of through holes are provided on the baffle.

[0019] Compared with the prior art, the beneficial technical effects of the present invention are:

[0020] (I) The present invention controls the increase in the internal temperature of the gunpowder starter by taking away heat through the vaporization of water in the annular cavity of the nozzle seat and the radiation heat transfer of the flange structure of the main shell and the nozzle seat, thereby avoiding the technical problem of the secondary gunpowder starter burning earlier than the scheduled time during the first start and working process of the liquid rocket engine due to the inability to isolate the high-temperature and high-pressure combustion gas. It also solves the technical problem that the insulation structure of the existing secondary start gunpowder starter is complicated in manufacturing and installation process and has a high probability of falling off, resulting in high starter cost and low reliability.

[0021] (II) The flange structure connection between the main shell and the nozzle seat in the present invention is changed from the contact connection in the prior art to the gap connection. Accordingly, the heat transfer mode between the flanges is changed from the conduction heat transfer in the prior art to the radiation heat transfer, which significantly reduces the heat transfer efficiency. At the same time, due to the existence of the gap, the end face of the first flange is fully open, which increases the channel for external radiation heat transfer while absorbing heat, greatly reducing the heat transfer between the shell and the nozzle seat.

[0022] (III) In the present invention, an annular cavity is provided on the nozzle seat, and a large amount of heat is absorbed by evaporating, vaporizing, and sublimating water in the annular cavity. The heat transferred from the nozzle seat outlet flange is carried away from the gunpowder starter in time through the vent holes on the nozzle seat shell using steam as a carrier. On the one hand, the temperature rise of the nozzle seat itself is prevented, the temperature difference between the nozzle seat and the main shell is reduced, and the heat that continues to be transferred to the main shell is greatly reduced; on the other hand, the steam takes away the heat, which generally reduces the total calorific value that causes the temperature rise of the gunpowder starter, thereby ensuring the overall temperature rise limit of the gunpowder starter.

[0023] (IV) Compared with the prior art, the present invention omits functional parts such as the thermal insulation pad, the first thermal insulation layer and the second thermal insulation layer, which on the one hand greatly reduces the product cost, and on the other hand makes the structure simpler and more reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0025] Figure 2 It is a schematic diagram of the connection gap between the main shell and the nozzle seat in the present invention;

[0026] Figure 3 It is a schematic cross-sectional structural diagram of the nozzle seat in the present invention;

[0027] Figure 4 It is a schematic diagram of the overall structure of the baffle in the present invention;

[0028] Figure 5 is a cross-sectional schematic diagram of the baffle in the present invention;

[0029] Figure 6It is a schematic diagram of the assembly structure of the diaphragm and the baffle in the present invention;

[0030] Figure 7 It is a schematic diagram of the assembly structure of the diaphragm, the baffle and the nozzle seat in the present invention;

[0031] Figure 8 It is a schematic diagram of the structure of the diaphragm in the present invention;

[0032] Fig. 9 It is a schematic diagram of the structure of the rubber plug in the present invention.

[0033] The meanings of the various reference numerals in the figure are as follows: main housing 1, nozzle seat 2, combustion chamber 3, first flange 4, second flange 5, fastening bolts 6, electric igniter 7, ignition bracket 8, medicine baffle 9, main charge 10, nozzle 11, gas diaphragm assembly 12, second sealing ring 13, buffer pad 14, elastic pad 15, ignition cartridge 16, nozzle seat outlet flange 17, through hole 18, groove 19, tenon 20;

[0034] Nozzle seat outer shell 201, nozzle seat inner cone shell 202, annular cavity 203, vent hole 204, rubber plug 205;

[0035] A first cavity 301, a second cavity 302, and a third cavity 303;

[0036] Baffle 1201, diaphragm 1202.

[0037] The specific contents of the present invention are further explained in detail below in conjunction with embodiments. DETAILED DESCRIPTION

[0038] It should be noted that, unless otherwise specified, all components in the present invention are components known in the art.

[0039] Specific embodiments of the present invention are given below. It should be noted that the present invention is not limited to the following specific embodiments, and all equivalent changes made on the basis of the technical solution of this application fall within the protection scope of the present invention.

[0040] The present invention provides a secondary powder starter, such as Figures 1 to 9 As shown, it includes a main shell 1 and a nozzle seat 2, the main shell 1 and the nozzle seat 2 are connected by a flange structure and a combustion chamber 3 is formed therein;

[0041] The flange structure includes a first flange 4 arranged on the end surface of the main shell 1 and a second flange 5 arranged on the end surface of the nozzle seat 2, and the first flange 4 and the second flange 5 are fixed by fastening bolts 6; there is a gap between the first flange 4 and the second flange 5, and matching grooves 19 and tenons 20 are respectively arranged on the end surfaces thereof, and a second sealing ring 13 is also arranged between the tenon 19 and the groove 20;

[0042] An electric igniter 7 is arranged at the axial front end of the main housing 1; an ignition bracket 8 and a medicine baffle 9 are arranged in the combustion chamber 3 in sequence along the axial direction, and the ignition bracket 8 and the medicine baffle 9 divide the combustion chamber 3 into a first cavity 301, a second cavity 302 and a third cavity 303. An ignition powder box 16 is arranged in the first cavity 301, and a main charge 10 is arranged in the second cavity 302;

[0043] The nozzle seat 2 includes a nozzle seat outer shell 201 and a nozzle seat inner cone shell 202, an annular cavity 203 is formed between the nozzle seat outer shell 201 and the nozzle seat inner cone shell 202, and water is arranged in the annular cavity 203; a vent hole 204 is arranged on the nozzle seat outer shell 201, and a rubber plug 205 is arranged in the vent hole 204; a nozzle 11 whose one end is connected to the third cavity 303 is arranged in the nozzle seat 2, and a gas diaphragm assembly 12 fixed on the inner wall of the nozzle seat 2 is arranged at the other end of the nozzle 11, and a nozzle seat outlet flange 17 is arranged at the axial rear end of the nozzle seat 2.

[0044] In the above technical scheme, when the secondary gunpowder starter does not need to ignite: during the operation of the gunpowder starter of the liquid rocket engine and the operation of the liquid rocket engine, high-temperature and high-pressure combustion gas will be generated. These high-temperature and high-pressure combustion gases are applied to the secondary gunpowder starter used for the engine throughout the process, specifically acting on the nozzle seat outlet flange 17 and the gas diaphragm assembly 12.

[0045] Insulation principle: The heat brought by the gas is transferred to the nozzle seat 2 and the gas diaphragm assembly 12. As the heat transferred increases, the temperature of the nozzle seat 2 and the gas diaphragm assembly 12 increases. Next: Path 1: The gas diaphragm assembly 12 heats the surrounding air and transfers heat (very small) to the combustion chamber 3 in a convection manner; Path 2: The nozzle seat 3 transfers heat to the water, the temperature of the water slowly increases, and it begins to evaporate, vaporize, and sublimate. The pressure of its cavity increases accordingly. When the temperature rises to boiling, or higher, and the pressure in the cavity is large enough, the rubber plug 205 in the vent 204 pops out under the action of pressure, and the water vapor also ejects, taking away the heat, thereby limiting the increase in the temperature of the nozzle seat 2. Another small part of the heat continues to be transferred along the nozzle seat 2 to the second flange 5 of the nozzle seat, causing the temperature of the second flange 5 to increase. Since this part of the heat is very small, the temperature rise is not high, and the temperature difference between it and the first flange 4 is not large. Since the two are radiated heat transfers, the transferred heat is very small, and the temperature rise of the total shell is even smaller.

[0046] When the secondary gunpowder starter needs to ignite, the electric igniter 7 is energized to ignite, igniting the ignition cartridge 16. The combustion of the ignition cartridge 16 generates fuel gas, which accumulates and increases in pressure under the sealing effect of the fuel gas diaphragm assembly 12. When the pressure value meets the critical pressure value of the main charge 10, the main charge 10 is ignited, and the pressure in the combustion chamber 3 is further increased. When it reaches a certain value, it breaks through the fuel gas diaphragm assembly 12 and is ejected from the nozzle 11 outlet to perform work.

[0047] In summary, the increase in the internal temperature of the gunpowder starter is controlled by taking away heat through the vaporization of water in the annular cavity 203 of the nozzle seat 2 and the radiation heat transfer of the flange structure of the main shell 1 and the nozzle seat 2, thereby avoiding the technical problem of the secondary gunpowder starter burning earlier than the scheduled time during the first start and working process of the liquid rocket engine due to the inability to isolate the high-temperature and high-pressure combustion gas. This solves the technical problem of the complicated manufacturing and installation process of the insulation structure in the existing secondary start gunpowder starter and the high probability of falling off, which leads to high starter cost and low reliability.

[0048] In this solution, the flange structural connection between the main shell and the nozzle seat is changed from the contact connection in the prior art to the gap connection. Accordingly, the heat transfer mode between the flanges is changed from the conduction heat transfer in the prior art to the radiation heat transfer, which significantly reduces the heat transfer efficiency. At the same time, due to the existence of the gap, the end face of the first flange is fully open, which increases the channel for external radiation heat transfer while absorbing heat, greatly reducing the heat transfer between the shell and the nozzle seat.

[0049] In this scheme, an annular cavity is provided on the nozzle seat, and a large amount of heat is absorbed by evaporating, vaporizing, and sublimating water in the annular cavity. The heat transmitted from the nozzle seat outlet flange is carried away from the gunpowder starter in time through the vent holes on the nozzle seat shell in the form of steam. On the one hand, the temperature rise of the nozzle seat itself is prevented, the temperature difference between the nozzle seat and the main shell is reduced, and the heat that continues to be transmitted to the main shell is greatly reduced; on the other hand, the steam takes away the heat, thereby reducing the total heat value that causes the temperature rise of the gunpowder starter as a whole, thereby ensuring the overall temperature rise limit of the gunpowder starter.

[0050] Specifically, the rubber stopper 205 is in a truncated cone shape, and its end surface with a small diameter is close to the annular cavity 203 .

[0051] In the above technical solution, the truncated cone-shaped rubber plug 205 is easy to install.

[0052] Specifically, a first sealing ring is provided between the main housing 1 and the electric igniter 7 .

[0053] In the above technical solution, the first sealing ring can achieve reliable sealing between the electric igniter 3 and the main housing 101. The first sealing ring and the second sealing ring are made of flexible graphite material or soft metal material, and the soft metal material includes but is not limited to aluminum and copper.

[0054] Specifically, a buffer pad 14 is provided between the ignition bracket 8 and the main charge 10.

[0055] In the above technical solution, the buffer pad 14 can compensate for the problem of deformation mismatch of each component caused by environmental temperature changes, and generally uses an elastic non-metallic material, such as aviation sponge rubber material.

[0056] Specifically, an elastic pad 15 is provided between the main charge 10 and the baffle 9.

[0057] In the above technical solution, the elastic pad 15 is used to buffer the vibration, shock and impact loads between the propellant column 10 and the baffle 8. The buffer pad generally uses an elastic non-metallic material, such as aviation sponge rubber material.

[0058] Specifically, the gas diaphragm assembly 12 includes a baffle 1201 and a diaphragm 1202 arranged in sequence along the axial direction.

[0059] Specifically, on one side of the diaphragm 1202 close to the outlet of the nozzle seat 2, there are engraved marks in the shape of a "rice" character, which ensures that the diaphragm can be more easily broken by the gas in the combustion chamber.

[0060] Specifically, both the baffle 1201 and the diaphragm 1202 are in the shape of a "concave", which ensures that no fragments will fall when the diaphragm is broken, avoiding damage to downstream components.

[0061] Specifically, a plurality of through holes 18 are provided on the baffle 1201.

[0062] In the above technical solution, the gas diaphragm assembly 12 makes the effective membrane-breaking area of the diaphragm 1202 different by providing a plurality of through holes 18 on the baffle 1201, so as to ensure that the gas generated during the first start-up and operation of the liquid rocket engine will not break through the diaphragm and enter the combustion chamber 3, while the gas generated by the combustion of the propellant column during the second start-up of the liquid rocket engine can reliably open the diaphragm 1202 and spray out from the nozzle 11 to do work.

Claims

1. A secondary powder starter, comprising a main housing (1) and a nozzle seat (2), characterized in that: The total housing (1) and the nozzle seat (2) are connected by a flange structure, and a combustion chamber (3) is formed inside; The flange structure includes a first flange (4) provided on the end face of the total housing (1) and a second flange (5) provided on the end face of the nozzle seat (2). The first flange (4) and the second flange (5) are fixed by fastening bolts (6); there is a gap between the first flange (4) and the second flange (5), and mating grooves (19) and tenons (20) are respectively provided on their end faces. A second sealing ring (13) is also provided between the tenon (19) and the groove (20); An electric igniter (7) is provided at the axial front end of the total housing (1); an ignition support (8) and a charge baffle (9) are sequentially arranged along the axis in the combustion chamber (3). The ignition support (8) and the charge baffle (9) divide the combustion chamber (3) into a first cavity (301), a second cavity (302), and a third cavity (303). An ignition cartridge (16) is provided in the first cavity (301), and a main charge (10) is provided in the second cavity (302); The nozzle seat (2) includes a nozzle seat outer shell (201) and a nozzle seat inner conical shell (202). An annular cavity (203) is formed between the nozzle seat outer shell (201) and the nozzle seat inner conical shell (202), and water is provided in the annular cavity (203); a vent hole (204) is provided on the nozzle seat outer shell (201), and a rubber plug (205) is provided in the vent hole (204); a nozzle (11) with one end communicating with the third cavity (303) is provided inside the nozzle seat (2), and the other end of the nozzle (11) is provided with a gas diaphragm assembly (12) fixed on the inner wall of the nozzle seat (2); a nozzle seat outlet flange (17) is provided at the axial rear end of the nozzle seat (2).

2. The secondary powder starter according to claim 1, characterized in that: The rubber plug (205) is frustum-shaped, and the end face with a smaller diameter is close to the annular cavity (203).

3. The secondary powder starter according to claim 1, characterized in that: A first sealing ring is provided between the total housing (1) and the electric igniter (7).

4. The secondary powder starter according to claim 1, characterized in that: A buffer pad (14) is provided between the ignition support (8) and the main charge (10).

5. The secondary powder starter according to claim 1, characterized in that: An elastic pad (15) is provided between the main charge (10) and the charge baffle (9).

6. The secondary powder starter according to claim 1, characterized in that: The gas diaphragm assembly (12) includes a baffle (1201) and a diaphragm (1202) arranged sequentially along the axis.

7. The secondary powder starter according to claim 6, characterized in that: On one side of the diaphragm (1202) close to the outlet of the nozzle seat (2), there are engraved marks in the shape of a "rice" character.

8. The secondary powder starter according to claim 6, characterized in that: Both the baffle (1201) and the diaphragm (1202) are in the shape of a "concave".

9. The secondary powder starter according to claim 6, wherein a plurality of through holes (18) are provided on the baffle (1201).

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