Gunpowder starter for secondary starting of engine based on double diaphragms

Abstract

The utility model discloses a gunpowder starter for secondary starting of an engine based on double diaphragms, which comprises a shell, and the shell comprises a main shell and a spray pipe seat which are sequentially connected along the axial direction; a combustion chamber is formed in the main shell and the spray pipe seat; an ignition powder box support, a powder blocking plate and a second diaphragm are arranged in the combustion chamber, the combustion chamber is divided into a first cavity, a second cavity, a third cavity and a fourth cavity through the ignition powder box support, the powder blocking plate and the second diaphragm, the double-diaphragm design is adopted, and the fourth cavity is formed between the second diaphragm and the first diaphragm. The mode that fuel gas heat is transmitted to the inside of the gunpowder starter is changed, an existing radiation and convection transmission mode is changed into a radiation and air conduction transmission mode, and due to the fact that the conduction efficiency of air in the fourth cavity is very low, transmission of heat to the inside of the gunpowder starter is reduced; the technical problem that the risk of igniting the gunpowder starter in advance for charging the gunpowder due to high heat generated in the contact area of the gunpowder column and the gunpowder baffle in the existing gunpowder starter is solved.

Description

Technical Field

[0001] The utility model belongs to the technical field of liquid rocket engines and relates to a gunpowder starter, in particular to a gunpowder starter for secondary starting of an engine based on double diaphragms. Background Art

[0002] Recoverable liquid launch vehicles require liquid rocket engines that can be started at least twice. The current technical approach is that liquid rocket engines are equipped with two gunpowder starters, which are used for the primary and secondary starts 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 engine is working and during the operation of the engine, high-temperature and high-pressure combustion gases are generated, and these high-temperature and high-pressure combustion gases are applied to the gunpowder starter used for the secondary start of the engine throughout the process.

[0003] In order to ensure that the gunpowder starter used for secondary engine starting can withstand the above harsh gas environment and reliably ignite itself, an isolation device needs to be designed. The functions of the isolation device are: on the one hand, it isolates the gas from entering the gunpowder starter used for secondary engine starting to prevent the high-temperature gas from igniting the gunpowder starter charge in advance; on the other hand, it ensures that the gunpowder starter used for secondary engine starting can be opened reliably during its own ignition work to prevent the secondary gunpowder starter charge from igniting and causing an explosion due to excessive pressure buildup. In addition, heat insulation measures must be taken to prevent heat conduction from causing the gunpowder starter shell temperature to be too high, which will ignite the gunpowder starter charge in advance.

[0004] The Chinese invention patent with the authorization announcement number CN114439648B discloses a gunpowder starter for secondary engine starting based on a double diaphragm, and proposes an isolation device, which is arranged at the outlet of the nozzle seat and consists of a baffle and a diaphragm. By setting multiple through holes on the baffle, the effective area of ​​the diaphragm is different when it is subjected to positive and reverse pressures, thereby ensuring that the gas generated during the primary start and operation of the liquid rocket engine will not break through the diaphragm and enter the starter combustion chamber, while the gas generated by the combustion of the powder column during the secondary start of the liquid rocket engine can reliably open the diaphragm. In engineering practice, the application of this isolation device has the following problems: ① The diaphragm manufacturing yield is low, the cycle is long, and the cost is high. The diaphragm faces many challenges in the molding process. The positive and reverse pressure difference is large, about tens of megapascals, or even tens of megapascals; the thickness of the diaphragm is thin, the thickness of the parent material is generally about 1.0mm, and the thickness at the notch even reaches 0.1mm; the dimensional accuracy control requirements are high, and the accuracy of the molding tool must reach the μm level. In addition, quality inspection can only adopt destructive testing methods. In order to ensure the consistency of batch products, it is necessary to increase the number of random sampling, which leads to low yield, long cycle and high cost. ② Actual monitoring shows that during the engine start-up and stable operation, the isolation device is in direct contact with the high-temperature gas, and the high-temperature gas continuously heats the isolation device, making the isolation device very hot. The high-temperature isolation device transfers heat through thermal radiation and convection, resulting in local high temperature in the third cavity, and a hot spot is generated in the contact area between the starter charge and the baffle, which poses a risk of premature ignition of the gunpowder starter charge. Utility Model Content

[0005] In view of the shortcomings of the prior art, the purpose of the utility model is to provide a gunpowder starter for secondary starting of an engine based on a double diaphragm, so as to solve the technical problems that high heat is generated in the contact area between the powder column and the powder baffle plate in the existing gunpowder starter, resulting in the risk of premature ignition of the gunpowder starter charge, and the low yield of the isolation diaphragm in the gunpowder starter.

[0006] In order to solve the above technical problems, the utility model adopts the following technical solutions:

[0007] A double-diaphragm-based gunpowder starter for secondary starting of an engine comprises a shell, the shell comprising a main shell and a nozzle seat connected in sequence along the axial direction; a combustion chamber is formed inside the main shell and the nozzle seat; an electric igniter is arranged at the axial front end of the main shell; a first heat insulating layer is arranged on the inner wall of the main shell, and a second heat insulating layer is arranged on the inner wall of the nozzle seat; a heat insulating pad is arranged between the main shell and the nozzle seat;

[0008] A primer cartridge support, a baffle plate, and a second diaphragm are provided in the combustion chamber. The primer cartridge support, the baffle plate, and the second diaphragm divide the combustion chamber into a first cavity, a second cavity, a third cavity, and a fourth cavity. A primer cartridge is fixedly installed in the first cavity, and one side of the primer cartridge is fixedly installed on the primer cartridge support; the other side of the primer cartridge is closely attached to the inner wall of the total housing; a propellant charge is axially arranged in the second cavity, one end of the propellant charge is connected to the primer cartridge support, and the other end is connected to the baffle plate;

[0009] A nozzle is detachably provided on the inner wall of the nozzle seat at the axially rear end of the second diaphragm. A baffle plate and a first diaphragm fixedly connected in sequence are axially arranged at the axially rear end of the nozzle. The baffle plate and the first diaphragm are fixedly arranged on the inner wall of the nozzle seat; a plurality of through holes are provided on the baffle plate.

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

[0011] A retaining ring is provided on the inner wall of the axially front end of the nozzle seat, and the second diaphragm is fixedly arranged on the retaining ring.

[0012] The total housing and the nozzle seat are connected by cooperation of a flange and fasteners, and the heat insulation pad is arranged between the flanges.

[0013] A first sealing ring is provided between the total housing and the electric igniter; a second sealing ring is provided between the flanges.

[0014] The electric igniter forms an angle α with the axis of the total housing, and the angle α is an acute angle.

[0015] The value of the angle α formed by the electric igniter and the axis of the total housing is 15° to 30°.

[0016] The fasteners include a self-locking nut and a bolt.

[0017] A compensation gasket is provided between the primer cartridge support and the propellant charge.

[0018] A buffer pad is provided between the propellant charge and the baffle plate.

[0019] On one side of the first diaphragm and the second diaphragm close to the outlet of the nozzle seat, there are both engraved with "cross" shaped notches.

[0020] Both the baffle plate and the first diaphragm are in a "concave" shape.

[0021] Compared with the prior art, the beneficial technical effects of the present utility model are:

[0022] (I) The present invention adopts a double diaphragm design to form a fourth cavity between the second diaphragm and the first diaphragm, thereby changing the way the heat of the fuel gas is transferred to the interior of the gunpowder starter from the radiation + convection transfer method of the prior art to the radiation + air conduction transfer method of the present invention. Since the air conduction efficiency is very low and can be ignored, the presence of the fourth cavity greatly reduces the transfer of heat to the interior of the gunpowder starter, reduces the possibility of high heat being generated in the contact area between the gunpowder column and the gunpowder baffle in the gunpowder starter, avoids the risk of premature ignition of the gunpowder starter charge, and solves the technical problem that the contact area between the gunpowder column and the gunpowder baffle in the existing gunpowder starter generates high heat, resulting in the risk of premature ignition of the gunpowder starter charge.

[0023] (II) The utility model adopts a double diaphragm design, in which the first diaphragm is responsible for the forward opening function of the gunpowder starter's own ignition, and the second diaphragm is responsible for the high pressure during the engine's primary start and stable operation. Compared with the prior art in which the diaphragm simultaneously performs the above two functions, the difficulty of forming the diaphragm in the manufacturing process is greatly reduced, thereby improving the yield and efficiency, reducing costs, and solving the technical problem of low yield of isolation diaphragms in gunpowder starters. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the overall structure of the utility model;

[0025] Figure 2 It is a schematic diagram of the overall structure of the baffle in the utility model;

[0026] Figure 3 It is a cross-sectional schematic diagram of the baffle in the utility model;

[0027] Figure 4 It is a schematic diagram of the assembly structure of the first diaphragm and the baffle in the utility model;

[0028] Figure 5 It is a schematic diagram of the assembly structure of the first diaphragm, the baffle plate and the nozzle seat in the utility model;

[0029] Figure 6 It is a schematic structural diagram of the first diaphragm in the utility model.

[0030] The meanings of the various numbers in the figure are: 1-housing, 2-combustion chamber, 3-electric igniter, 4-first insulation layer, 5-second insulation layer, 6-insulation pad, 7-ignition cartridge bracket, 8-cartridge baffle, 9-ignition cartridge, 10-cartridge column, 11-nozzle, 12-baffle, 13-first diaphragm, 14-through hole, 15-flange, 16-fastener, 17-first sealing ring, 18-second sealing ring, 19-compensation gasket, 20-buffer pad, 21-second diaphragm, 22-baffle ring;

[0031] 101- main housing, 102- nozzle seat;

[0032] 201-first cavity, 202-second cavity, 203-third cavity, 204-fourth cavity;

[0033] 1601-Self-locking nut, 1602-Bolt.

[0034] The specific contents of the utility model are further explained in detail below in conjunction with the embodiments. DETAILED DESCRIPTION

[0035] It should be noted that, unless otherwise specified, all components in the present invention are components known in the art.

[0036] The following are specific embodiments of the present invention. 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 the present application fall within the protection scope of the present invention.

[0037] The utility model provides a gunpowder starter for secondary starting of an engine based on a double diaphragm, such as Figures 1 to 6 As shown, it comprises a housing 1, and the housing 1 comprises a main housing 101 and a nozzle seat 102 which are connected in sequence along the axial direction; the interior of the main housing 101 and the nozzle seat 102 forms a combustion chamber 2;

[0038] An electric igniter 3 is provided at the axial front end of the main shell 101; a first heat insulating layer 4 is provided on the inner wall of the main shell 101, and a second heat insulating layer 5 is provided on the inner wall of the nozzle seat 102; a heat insulating pad 6 is provided between the main shell 101 and the nozzle seat 102;

[0039] An ignition cartridge holder 7, a medicine baffle plate 8 and a second diaphragm 21 are arranged in the combustion chamber 2. The ignition cartridge holder 7, the medicine baffle plate 8 and the second diaphragm 21 divide the combustion chamber 2 into a first cavity 201, a second cavity 202, a third cavity 203 and a fourth cavity 204. An ignition cartridge 9 is fixedly installed in the first cavity 201, and one side of the ignition cartridge 9 is fixedly installed on the ignition cartridge holder 7; the other side of the ignition cartridge 9 is in close contact with the inner wall of the main shell 101; a medicine column 10 is axially arranged in the second cavity 202, and one end of the medicine column 10 is connected to the ignition cartridge holder 7, and the other end is connected to the medicine baffle plate 8;

[0040] A nozzle 11 is detachably provided on the inner wall of the nozzle seat 102 at the axial rear end of the second diaphragm 21, and a baffle 12 and a first diaphragm 13 are fixedly connected to each other in sequence along the axial direction at the axial rear end of the nozzle 11. The baffle 12 and the first diaphragm 13 are fixedly provided on the inner wall of the nozzle seat 102; a plurality of through holes 14 are provided on the baffle 12.

[0041] In the above technical scheme, a double diaphragm design is adopted to form a fourth cavity between the second diaphragm 21 and the first diaphragm 13, which changes the way the heat of the gas is transferred to the inside of the gunpowder starter, from the radiation + convection transfer method of the prior art to the radiation + air conduction transfer method of the utility model. Since the air conduction efficiency is very low and can be ignored, the existence of the fourth cavity greatly reduces the transfer of heat to the inside of the gunpowder starter, reduces the possibility of high heat generated in the contact area between the powder column 10 and the powder baffle plate 8 in the gunpowder starter, avoids the risk of premature ignition of the gunpowder starter charge, and solves the technical problem that the contact area between the powder column and the powder baffle plate in the existing gunpowder starter generates high heat, resulting in the risk of premature ignition of the gunpowder starter charge.

[0042] In addition, a double diaphragm design is adopted, in which the second diaphragm 21 is responsible for the forward opening function of the gunpowder starter's own ignition, and the first diaphragm 13 is responsible for the high pressure during the engine's primary start and its stable operation. Compared with the diaphragm in the prior art that simultaneously performs the above two functions, the difficulty of forming the diaphragm in the manufacturing process is greatly reduced, thereby improving the yield and efficiency, reducing costs, and solving the technical problem of low yield of isolation diaphragms in gunpowder starters.

[0043] The gunpowder starter nozzle is an energy conversion device that converts the heat energy of the high-temperature and high-pressure gas generated by the combustion of gunpowder in the gunpowder starter combustion chamber into the kinetic energy of the gas at the nozzle outlet. According to the principle of thermodynamics, the kinetic energy of the gas increases, and the internal energy and potential energy decrease, that is, the temperature and pressure of the gas decrease. It is precisely because of this effect of the nozzle that even if the pressure in the gunpowder starter combustion chamber is very high, the pressure at the nozzle outlet will drop significantly and become lower. If the diaphragm is set at the nozzle outlet, the positive opening pressure of the diaphragm is required to be correspondingly small. In the case where the pressure in the direction of the diaphragm remains unchanged, the positive and negative pressure difference of the diaphragm is large, which is not conducive to the control of manufacturing quality. In this application, a double diaphragm is used, and the second diaphragm is set at the axial front end of the nozzle. The pressure acting on the second diaphragm is the pressure directly generated by the combustion of gunpowder. This data is large, that is, the membrane breaking pressure requirement is high, and the second diaphragm only bears the positive membrane breaking effect, and the manufacturing quality is easy to control and the difficulty is small. In this way, the first diaphragm only needs to bear the reverse pressure bearing effect, and there is no need to consider the dual requirements of forward and reverse at the same time, and the manufacturing difficulty is correspondingly reduced.

[0044] Specifically, a retaining ring 22 is provided on the inner wall of the axial front end of the nozzle seat 102 , and the second diaphragm 21 is fixedly provided on the retaining ring 22 .

[0045] Preferably, the nozzle holder 102 is threadedly connected to the inner wall of the nozzle holder 102 .

[0046] Specifically, the main shell 101 and the nozzle seat 102 are connected by the flange 15 and the fastener 16 , and the thermal insulation pad 6 is arranged between the flanges 15 .

[0047] Specifically, a first sealing ring 17 is provided between the overall housing 101 and the electric igniter 3, and a second sealing ring 18 is provided between the flanges 15. Under the action of a specified tightening torque, the first sealing ring 17 can achieve reliable sealing between the electric igniter 3 and the overall housing 101, and the second sealing ring 18 can achieve reliable sealing between the overall housing 101 and the nozzle base 102, and is resistant to high temperatures.

[0048] 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.

[0049] Specifically, the electric igniter 3 forms an angle α with the axis of the overall housing 101, and the angle α is an acute angle. Compared with the prior art solution where the electric igniter is in the same direction along the central axis of the front head, the axial dimension of the pyrotechnic starter can be reduced.

[0050] Specifically, the value of the angle α between the electric igniter 3 and the axis of the overall housing 101 is 15° to 30°, and the axial dimension of the pyrotechnic starter can be reduced by 3% to 13%.

[0051] Specifically, the fastener 16 includes a self-locking nut 1601 and a bolt 1602, ensuring that it will not loosen under the action of vibration, shock, and impact loads.

[0052] Specifically, a compensation gasket 19 is provided between the ignition cartridge support 7 and the propellant column 10, which can compensate for the problem of mismatched deformation of each component caused by environmental temperature changes.

[0053] The compensation gasket is made of elastic non-metallic material, such as aviation sponge rubber material.

[0054] Specifically, a buffer pad 20 is provided between the propellant column 10 and the baffle 8 to buffer the vibration, shock, and impact loads between the propellant column 10 and the baffle 8.

[0055] The buffer pad is made of elastic non-metallic material, such as aviation sponge rubber material.

[0056] Specifically, on one side of the first diaphragm 13 and the second diaphragm 21 close to the outlet of the nozzle base 102, there are both "cross" - shaped indentations, ensuring that the first diaphragm 13 and the second diaphragm 21 can be more easily broken through by the combustion gas in the combustion chamber.

[0057] Specifically, the baffle 12 and the first diaphragm 13 are both "concave" - shaped, ensuring that no fragments will fall when the first diaphragm 13 is broken through, avoiding damage to downstream components.

Claims

1. A pyrotechnic starter for the secondary starting of an engine based on a double diaphragm, comprising a housing (1), wherein the housing (1) includes a general housing (101) and a nozzle seat (102) connected in sequence along the axial direction; a combustion chamber (2) is formed inside the general housing (101) and the nozzle seat (102); an electric igniter (3) is arranged at the axial front end of the general housing (101); a first heat insulation layer (4) is arranged on the inner wall of the general housing (101), and a second heat insulation layer (5) is arranged on the inner wall of the nozzle seat (102); a heat insulation pad (6) is arranged between the general housing (101) and the nozzle seat (102); It is characterized in that An ignition cartridge support (7), a medicine blocking plate (8) and a second diaphragm (21) are arranged in the combustion chamber (2), and the ignition cartridge support (7), the medicine blocking plate (8) and the second diaphragm (21) divide the combustion chamber (2) into a first cavity (201), a second cavity (202), a third cavity (203) and a fourth cavity (204). An ignition cartridge (9) is fixedly installed in the first cavity (201), and one side of the ignition cartridge (9) is fixedly installed on the ignition cartridge support (7); the other side of the ignition cartridge (9) is closely attached to the inner wall of the general housing (101); a propellant column (10) is arranged axially in the second cavity (202), one end of the propellant column (10) is connected to the ignition cartridge support (7), and the other end is connected to the medicine blocking plate (8); A nozzle (11) is detachably arranged on the inner wall of the nozzle seat (102) at the axial rear end of the second diaphragm (21). A baffle plate (12) and a first diaphragm (13) which are fixedly connected in sequence along the axial direction are arranged at the axial rear end of the nozzle (11), and the baffle plate (12) and the first diaphragm (13) are fixedly arranged on the inner wall of the nozzle seat (102); a plurality of through holes (14) are arranged on the baffle plate (12).

2. The gunpowder starter for secondary starting of an engine based on a double diaphragm as claimed in claim 1, characterized in that: A retaining ring (22) is arranged on the inner wall at the axial front end of the nozzle seat (102), and the second diaphragm (21) is fixedly arranged on the retaining ring (22).

3. The gunpowder starter for secondary starting of an engine based on a double diaphragm as claimed in claim 1, characterized in that: The general housing (101) and the nozzle seat (102) are connected by matching of a flange (15) and a fastener (16), and the heat insulation pad (6) is arranged between the flanges (15).

4. The gunpowder starter for secondary starting of an engine based on a double diaphragm as claimed in claim 3, characterized in that: A first sealing ring (17) is arranged between the general housing (101) and the electric igniter (3); a second sealing ring (18) is arranged between the flanges (15).

5. The gunpowder starter for secondary starting of an engine based on a double diaphragm as claimed in claim 1, characterized in that: The electric igniter (3) forms an angle α with the axial direction of the general housing (101), and the angle α is an acute angle.

6. The gunpowder starter for secondary starting of an engine based on a double diaphragm as claimed in claim 5, characterized in that: The value of the angle α between the electric igniter (3) and the axial direction of the general housing (101) is 15° to 30°.

7. The gunpowder starter for secondary starting of an engine based on a double diaphragm as claimed in claim 3, characterized in that: The fastener (16) includes a self-locking nut (1601) and a bolt (1602).

8. The double-diaphragm-based powder starter for secondary engine starting as claimed in claim 1, characterized in that: A compensation gasket (19) is arranged between the ignition cartridge support (7) and the propellant column (10).

9. The gunpowder starter for secondary starting of an engine based on a double diaphragm as claimed in claim 1, characterized in that: A buffer pad (20) is arranged between the propellant column (10) and the medicine blocking plate (8).

10. The double-diaphragm-based powder starter for secondary engine starting as claimed in claim 1, characterized in that: On one side of the first diaphragm (13) and the second diaphragm (21) close to the outlet of the nozzle seat (102), there are both engraved with "cross" shaped marks.

11. The double-diaphragm-based powder starter for secondary engine starting as claimed in claim 1, characterized in that: The baffle (12) and the first diaphragm (13) are both in a "concave" shape.

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