Liquid oxygen kerosene pintle injection equipment based on impinging mixed flow and starting method of liquid oxygen kerosene pintle injection equipment

Abstract

The invention belongs to the technical field of liquid oxygen rocket engines, particularly discloses liquid oxygen kerosene pintle injection equipment based on impinging mixed flow and a starting method of the liquid oxygen kerosene pintle injection equipment, and aims at solving the problems that an existing direct-current or centrifugal injection type generator is complex in structural design and machining process and high in cost. The device comprises a pintle injector, a generator, an igniter channel, a kerosene circulation channel and a liquid oxygen circulation channel, the pintle injector comprises a central cylinder, a central rod and a shell; a kerosene flowing channel is formed between the central cylinder and the central rod; a liquid oxygen circulation channel is formed between the central cylinder and the shell; the generator comprises a head and a combustion chamber; the igniter channel comprises a gunpowder igniter gas channel; the gunpowder ignition scheme suitable for the pintle injector is designed according to the unique structural characteristics and combustion flow field characteristics of the pintle injector, the structure is simple, and ignition is reliable.

Description

Technical Field

[0001] The invention belongs to the technical field of liquid oxygen rocket engines, and in particular relates to liquid oxygen-kerosene pintle injection equipment based on impact mixed flow and a starting method thereof. Background Art

[0002] The pintle injector originated from the experimental research on the mixing and combustion reaction time of liquid hypergolic propellants at the Jet Propulsion Laboratory in the United States in the mid-1950s. It is currently widely used in variable thrust or fixed thrust liquid rocket engines. Liquid oxygen-kerosene propellant has a high density and specific impulse, making it the best choice for the first stage of a launch vehicle. The pintle injector thrust chamber using liquid oxygen / kerosene propellant has a wide range of application prospects, especially in the field of first stage recovery and reuse of launch vehicles, which can significantly reduce the launch cost of launch vehicles.

[0003] Liquid oxygen and kerosene are non-hypergolic propellants, and reliable ignition is the basis for the reliable operation of the pintle injector generator using liquid oxygen and kerosene as propellant. Common ignition methods for ignition of liquid oxygen and kerosene propellants: ignition agent ignition, torch ignition, and gunpowder ignition. The ignition agent ignition solution has a complex supply system and requires carrying an ignition agent magic box and supply system. The gunpowder ignition solution has a simple installation structure and reliable ignition. The gunpowder ignition solution is widely used in centrifugal injector thrust chambers and DC injector thrust chambers. However, the pintle injector is a center-mounted, single-nozzle structure. The combustion flow field structure is significantly different from the DC and centrifugal nozzles. The flow intensity distribution of centrifugal injector generators and DC injector generators is uniform, and the application of uniform flow intensity distribution on the pintle injector generator is rare, and the pintle injector has a large flow intensity gradient, so the pintle injector is more difficult to ignite. Summary of the invention

[0004] The present invention provides a liquid oxygen-kerosene pintle injection device based on impact mixed flow and a starting method thereof to solve the problems of complex structural design, complex processing technology and high cost of existing direct current or centrifugal injection generators.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] The liquid oxygen-kerosene pintle injection device based on impact mixed flow comprises a pintle injector, which comprises a center tube, a center rod and a shell; a liquid oxygen flow channel is formed between the center tube and the shell; a kerosene flow channel is formed between the center tube and the center rod; and main and auxiliary kerosene nozzles are evenly arranged around the side of the rear end of the center tube;

[0007] The generator comprises an upper cover, a shell, and a combustion chamber connected in sequence from front to back, the shell is connected to the end of the combustion chamber, and an upper cover is provided at the other end of the combustion chamber;

[0008] The igniter channel includes a powder igniter gas channel disposed on the outer side of the upper cover, and a connecting flange is disposed at the outer end of the powder igniter gas channel;

[0009] The kerosene flow channel and the liquid oxygen flow channel have an outlet corresponding to each other to form a collision mixing flow region.

[0010] On the basis of the above technical solution, the present invention also provides the following optional technical solution:

[0011] In an optional scheme: the kerosene circulation channel includes a collector for introducing kerosene on the combustion chamber, a regenerative cooling interlayer arranged in the combustion chamber and the shell, and a kerosene channel arranged between the upper cover and the center tube; the kerosene of the kerosene main and auxiliary nozzle jets collides with the liquid oxygen of the liquid oxygen injection annular seam axis jet to form a spray fan, one end of the regenerative cooling interlayer is connected to the collector, and the other end thereof is connected to the shell.

[0012] In an optional solution, the outer diameter of the center tube at one end close to the liquid oxygen injection annular gap is the same as the outer diameter of the center tube at one end of the kerosene main and auxiliary nozzles.

[0013] In an optional solution: the two layers of offset spray fans impact the inner wall of the combustion chamber to form two offset cooling rings.

[0014] In an optional solution, the axis of the gas channel of the powder igniter forms an angle of α° with the axis of the combustion chamber, α°=10°~30°, and the distance D between the inner extension line of the gas channel of the powder igniter and the outer edge of the center tube is D=10mm~30mm;

[0015] The angle between the spray fan and the axis of the combustion chamber is β°, β°=60°~80°.

[0016] In an optional solution: the kerosene passage further comprises a kerosene pre-injection pressure pipe nozzle for pressure measurement and a kerosene pre-injection pulsation pressure measurement pipe nozzle for pulsation pressure measurement arranged on the upper cover;

[0017] The liquid oxygen passage also includes a liquid oxygen pre-spray pulsation pressure measuring nozzle arranged on the shell for pulsation pressure measurement and a liquid oxygen pre-spray pressure measuring nozzle for pressure measurement.

[0018] In the optional scheme: three evenly distributed reinforcing ribs are provided on the center tube, which are used for locking and supporting the center tube and the center rod by self-locking nuts; the upper cover, the center tube and the shell are fixed by standard bolts; a graphite sealing ring is provided between the upper cover and the center tube for sealing; a rubber ring is provided between the upper cover and the shell for sealing; a pan-seal ring is provided between the center tube and the shell for low-temperature sealing, and an opening adjustment gasket is crimped between the center tube and the shell to adjust the throttling area of ​​the liquid oxygen flow channel.

[0019] In the optional solution: the combustion chamber, the shell, the center tube, and the upper cover are all formed based on additive manufacturing + fine processing; the combustion chamber is welded to the inner wall surface of the shell, and the outer wall surface is welded into a whole through a connecting ring.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] 1. The present invention designs a gunpowder ignition scheme suitable for the pintle injector in view of the unique structural characteristics and combustion flow field characteristics of the pintle injector, which has a simple structure and reliable ignition.

[0022] 2. The liquid oxygen-kerosene pintle injection equipment based on impact mixed flow proposed in the present invention has a simple generator structure, low processing cost, high structural reliability, and can be reused many times compared to direct current chamber injectors and centrifugal injectors.

[0023] 3. The liquid oxygen-kerosene pintle injection equipment based on impact mixed flow proposed in the present invention is provided with a cavity reversal hole between the oxygen pre-spray cavity and the liquid oxygen collecting ring, which can shorten the gas-liquid injection process and injection uniformity of the startup process while ensuring that the pre-spray cavity is as small as possible. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1-1 A schematic diagram of the structure of one side of the liquid oxygen-kerosene needle injection device based on impact mixed flow of the present invention;

[0025] Figure 1-2 The other side structural diagram of the liquid oxygen-kerosene needle injection device based on impact mixed flow of the present invention;

[0026] Figure 1-3 A schematic diagram of the end structure of the liquid oxygen-kerosene needle injection device based on impact mixed flow of the present invention;

[0027] Figure 2 A schematic diagram of the combustion chamber structure in the liquid oxygen-kerosene pintle injection device based on impact mixed flow of the present invention;

[0028] Figure 3 A schematic diagram of the connecting ring structure in the liquid oxygen-kerosene needle injection device based on impact mixed flow of the present invention;

[0029] Figure 4-1 A schematic structural diagram of one side of the shell of the liquid oxygen-kerosene needle injection device based on impact mixed flow of the present invention;

[0030] Figure 4-2 A schematic diagram of the structure of the other side of the shell in the liquid oxygen-kerosene needle injection device based on impact mixed flow of the present invention;

[0031] Figure 4-3 Axonometric view of the housing in the liquid oxygen-kerosene needle injection device based on impact mixed flow of the present invention;

[0032] Figure 5 A schematic diagram of the structure of the opening adjustment gasket in the liquid oxygen-kerosene needle injection device based on impact mixed flow of the present invention;

[0033] Figure 6 A schematic diagram of the central tube structure in the liquid oxygen-kerosene needle injection device based on impact mixed flow of the present invention;

[0034] Figure 7-1 A schematic structural diagram of the upper side of the upper cover in the liquid oxygen-kerosene needle injection device based on impact mixed flow of the present invention;

[0035] Figure 7-2 A schematic structural diagram of the bottom of the upper cover in the liquid oxygen-kerosene needle injection device based on impact mixed flow of the present invention;

[0036] Figure 8 A schematic diagram of the guide cone structure in the liquid oxygen-kerosene needle injection device based on impact mixed flow of the present invention;

[0037] Figure 9-1 A schematic diagram of the central rod structure in the liquid oxygen-kerosene needle injection device based on impact mixed flow of the present invention;

[0038] Figure 9-2 A schematic structural diagram of the arrangement of the self-impact cooling nozzle in the liquid oxygen-kerosene pintle injection device based on impingement mixed flow of the present invention;

[0039] Fig.10 A schematic diagram of the structure of the vibration measuring support in the liquid oxygen-kerosene needle injection device based on impact mixed flow of the present invention;

[0040] Fig.11 A schematic diagram of the positioning key structure in the liquid oxygen-kerosene needle injection device based on impact mixed flow of the present invention.

[0041] Notes on reference numerals: 01-combustion chamber; 02-connecting ring; 03-housing; 04-opening adjustment gasket; 05-center tube; 06-upper cover; 07-guiding cone; 08-center rod; 09-vibration measuring support; 10-positioning key; 11-panel seal ring; 12-graphite seal ring; 13-self-locking nut; 14-rubber ring; 15-standard bolt; 011-gas outlet; 012-collector pressure measuring pipe nozzle; 013-kerosene inlet; 014-collector; 015-combustion chamber regeneration cooling interlayer; 031-liquid oxygen collector pulsation pressure measuring pipe nozzle; 032-propellant igniter gas channel; 0 33-shell drainage pipe; 034-liquid oxygen inlet; 035-shell regeneration cooling interlayer; 036-liquid oxygen collecting ring; 037-liquid oxygen pre-spray pressure measuring nozzle; 038-chamber pressure measuring nozzle; 039-liquid oxygen discharge trough; 051-kerosene main and auxiliary nozzles; 052-reinforcement ribs; 053-kerosene discharge trough; 054-liquid oxygen injection annular seam; 061-kerosene pre-spray pressure measuring nozzle; 062-kerosene pre-spray pulsating pressure measuring nozzle; 063-U-shaped reflux chamber on the upper cover; 064-flow equalization net; 081-self-impact cooling nozzle; 082-positioning groove; 083-locking thread; 084-spray fan. DETAILED DESCRIPTION

[0042] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0043] As shown in Figure 1- Fig.11 As shown, an embodiment of the present invention provides a liquid oxygen-kerosene pintle injection device based on impact mixed flow, including a pintle injector, a thrust chamber, a powder igniter gas channel, a liquid oxygen circulation channel, and a kerosene circulation channel;

[0044] The pintle injector includes a center tube 05, a center rod 08 and a self-locking nut 13, all of which are rotating bodies. The center tube 05 is fixed to the center rod 08 by a positioning key 10 and a self-locking nut 13. Three evenly distributed reinforcing ribs 052 are provided on the center tube 05, which are used for the self-locking nut 13 to lock and support the center tube 05 and the center rod 08. The rear end of the center tube 05 is processed with a main and auxiliary kerosene nozzle 051, and the kerosene enters from the center tube 05. After the center tube 05 and the center rod 08 are assembled, a kerosene circulation channel is formed. The locking thread 083 on the upper end of the center rod and the self-locking nut 13 are coated with glue to prevent loosening. The material of the center rod 08 is a high-temperature alloy. The pintle head is provided with two circles of self-impact cooling nozzles 081, which can effectively cool the end of the center rod 08.

[0045] The generator includes an upper cover 06, a central tube 05, a shell 03, and a combustion chamber 01 connected from front to back, all of which are based on additive manufacturing + fine processing. The combustion chamber 01 is welded to the inner wall of the shell 03, and the outer wall is welded into a whole through a connecting ring 02.

[0046] The upper cover 06, the center tube 05 and the shell 03 are fixed by standard bolts 15. A graphite sealing ring 12 is provided between the upper cover 06 and the center tube 05 for sealing. A rubber ring 14 is provided between the upper cover 06 and the shell 03 for sealing. A pan seal 11 is provided between the center tube 05 and the shell 03 for low-temperature sealing. An opening adjustment gasket 04 is crimped between the center tube 05 and the shell 03 to adjust the throttling area of ​​the liquid oxygen flow channel.

[0047] As shown in FIG1 , a plurality of primary and secondary nozzles 051 are evenly distributed between the center rod 08 and the rear end surface of the center tube 05 . The outer diameter of the center tube 05 located near the end of the liquid oxygen injection annular gap 054 is the same as the outer diameter of the center tube 05 near the end of the kerosene primary and secondary nozzles 051 .

[0048] As shown in Figure 1, the axis of the gunpowder igniter gas channel 032 forms an angle α° with the axis of the combustion chamber 01, α°=10°~30°, and the distance D between the inner extension line of the gunpowder igniter gas channel 032 and the outer edge of the center tube 05 is D=10mm~30mm, which ensures that the ignition agent is sprayed into the area where the spray fan is relatively well atomized and the mixing ratio is appropriate during ignition, which is conducive to reliable ignition.

[0049] When the generator is started, the oxygen-rich fuel gas of the gunpowder igniter is sprayed into the combustion chamber 01 along the axis through the gunpowder igniter fuel gas channel 032, and contacts with a small amount of kerosene in the radial kerosene nozzle jet and liquid oxygen in the axial jet. The kerosene starts to burn with the liquid oxygen under the heating of the high-temperature flame, and the generator completes the ignition.

[0050] As shown in Figure 1, the kerosene circulation channel includes a kerosene inlet 013 entering the collector 014, a combustion chamber regenerative cooling interlayer 015, a shell regenerative cooling interlayer 035, a shell drainage pipe 033, and an upper cover U-shaped reflux cavity 063. It enters from the upper end of the center tube 05, and the main and auxiliary kerosene nozzles 051 jets are evenly arranged in a circle between the center tube 05 and the center rod 08, forming a complete kerosene channel.

[0051] After liquid oxygen and kerosene enter the generator, they collide to form a spray fan 084 with an angle α with the thrust chamber axis. α is obtained through injection parameter calculation. The impact point between the spray fan 084 and the inner wall of the combustion chamber 01 forms two offset cooling rings.

[0052] The regenerative cooling interlayer arranged in the combustion chamber 01 and the shell 03 is connected to the collector 014 at one end and connected to the kerosene main and auxiliary nozzles 051 formed by the center tube 05 and the center rod 08 at the other end.

[0053] The pre-injection cavity should be as small as possible to shorten the gas-liquid injection process during the startup process and improve the thermal protection of the combustion chamber. A small pre-injection cavity will lead to poor uniformity, and the injection uniformity is ensured by using the liquid oxygen cavity turning hole.

[0054] As shown in Figures 4 and 7, a liquid oxygen collector pressure measuring nozzle 037 is provided on the shell 03, a room pressure measuring nozzle 038 is provided on the shell 03, a collector pressure measuring nozzle 012 is provided on the collector 014, and a liquid oxygen pre-spray pressure measuring nozzle 061 is provided on the upper cover 06, which are respectively used to measure the pressure at various locations, detect the flow resistance, and ensure the operation of the generator.

[0055] The method for starting the liquid oxygen-kerosene needle injection device based on impact mixed flow comprises the following steps:

[0056] Step 1: The kerosene in the kerosene circulation channel passes through the collector 014, the combustion chamber regeneration cooling interlayer 015, the shell regeneration cooling interlayer 035, the shell drainage pipe 033, and the upper cover U-shaped reflux cavity 063, and enters from the upper end of the central tube 05. The main and auxiliary kerosene nozzle jets are evenly arranged in the main and auxiliary heights around the central tube 05 and the central rod 08;

[0057] Step 2: Liquid oxygen enters the liquid oxygen collector 036 from the liquid oxygen inlet 034, enters the liquid oxygen injection annular gap 054 through the liquid oxygen collecting ring cavity hole, and the liquid oxygen axial jet collides with the kerosene jets of the kerosene main and auxiliary nozzles to form a spray fan 084, wherein the impact point of the spray fan and the inner wall of the combustion chamber is misaligned to form two cooling rings;

[0058] Step 3: The oxygen-rich fuel gas of the gunpowder igniter is injected into the combustion chamber 01 along the axis through the gunpowder igniter fuel gas channel 032, and contacts with a small amount of kerosene in the radial kerosene nozzle jet and liquid oxygen in the axial jet to achieve ignition.

[0059] Furthermore, in step 2, after the generator is turned off, the residual liquid oxygen in the liquid oxygen injection annular gap 054 is blown away by nitrogen, and at intervals of 0.2 to 0.5 seconds, the residual kerosene in the central barrel is quietly blown away by nitrogen, providing conditions for the secondary start-up of the generator.

[0060] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. Liquid oxygen and kerosene needle injection equipment based on impact mixed flow, characterized by: The needle injector comprises a central tube (05), a central rod (08) and a shell (03); a liquid oxygen flow channel is formed between the central tube (05) and the shell (03); a kerosene flow channel is formed between the central tube (05) and the central rod (08); and a kerosene main and auxiliary nozzles (051) are evenly arranged around the rear end side of the central tube (05); The generator comprises an upper cover (06), a shell (03), and a combustion chamber (01) connected in sequence from front to back, the shell (03) is connected to the end of the combustion chamber (01), and the other end of the combustion chamber (01) is matched with an upper cover (06); An igniter channel, comprising a powder igniter gas channel (032) arranged outside the upper cover (06), wherein the outer end of the powder igniter gas channel (032) is provided with a connecting flange; The kerosene flow channel and the liquid oxygen flow channel have an outlet corresponding to each other to form a collision mixing flow region.

2. The liquid oxygen-kerosene pintle injection equipment based on impingement mixed flow according to claim 1 is characterized in that: The kerosene circulation channel comprises a collector (014) for introducing kerosene on the combustion chamber (01), a regenerative cooling interlayer arranged in the combustion chamber (01) and the shell (03), and a kerosene channel arranged between the upper cover (06) and the central tube (05); the kerosene jets from the kerosene main and auxiliary nozzles (051) collide with the liquid oxygen jets from the axial line of the liquid oxygen injection annular gap (054) to form a spray fan (084); one end of the regenerative cooling interlayer is connected to the collector (014), and the other end thereof is connected to the shell (03).

3. The liquid oxygen-kerosene pintle injection equipment based on impingement mixed flow according to claim 2 is characterized in that: The outer diameter of the center tube (05) located at one end close to the liquid oxygen injection annular gap (054) is the same as the outer diameter of the center tube (5) located at one end close to the kerosene main and auxiliary nozzles (051).

4. The liquid oxygen-kerosene pintle injection equipment based on impingement mixed flow according to claim 3 is characterized in that: The collision points of the two-layer offset spray fan (084) and the inner wall surface of the combustion chamber (01) form two offset cooling rings.

5. The liquid oxygen-kerosene pintle injection equipment based on impingement mixed flow according to claim 4 is characterized in that: The axis of the powder igniter gas channel (032) forms an angle α° with the axis of the combustion chamber (01), α°=10°-30°, and the distance D between the inner extension line of the powder igniter gas channel (032) and the outer edge of the center tube (05) is D=10mm-30mm; The angle between the spray fan (084) and the axis of the combustion chamber (01) is β°, where β°=60°-80°.

6. The liquid oxygen-kerosene pintle injection equipment based on impingement mixed flow according to claim 5 is characterized in that: The kerosene passage also includes a kerosene pre-injection pressure-connection nozzle (061) for pressure measurement and a kerosene pre-injection pulsation pressure measurement nozzle (062) for pulsation pressure measurement, which are arranged on the upper cover (06).

7. The liquid oxygen-kerosene pintle injection equipment based on impingement mixed flow according to claim 6 is characterized in that: The central tube (05) is fixedly assembled with the central rod (08) via a positioning key (10) and a self-locking nut (13); The central tube (05) is provided with three evenly distributed reinforcing ribs (052) for the self-locking nut (13) to lock and support the central tube (05) and the central rod (08); The upper cover (06), the central tube (05) and the shell (03) are fixed by means of standard bolts (15); a graphite sealing ring (12) is provided between the upper cover (06) and the central tube (05) for sealing; a rubber ring (14) is provided between the upper cover (06) and the shell (03) for sealing; a pan seal ring (11) is provided between the central tube (05) and the shell (03) for low-temperature sealing, and an opening adjustment gasket (04) is crimped between the central tube (05) and the shell (03) for continuously adjusting the throttling area of ​​the liquid oxygen flow channel.

8. A method for starting a liquid oxygen-kerosene needle injection device based on impact mixed flow according to any one of claims 1 to 7, characterized in that: The following steps are involved: Step 1: The kerosene in the kerosene circulation channel enters the collector (014), the combustion chamber regeneration cooling interlayer (015), the shell regeneration cooling interlayer (035), the shell drainage pipe (033), and the upper cover U-shaped reflux cavity (063) through the kerosene inlet (013), and enters from the upper end of the central tube (05), and the main and auxiliary kerosene nozzles (051) are evenly arranged in a circle between the central tube (05) and the central rod (08); Step 2: Liquid oxygen enters the liquid oxygen collector (036) from the liquid oxygen inlet (034), enters the liquid oxygen injection annular gap (054) through the liquid oxygen collecting ring cavity hole, and collides with the kerosene radially jetted from the kerosene main and auxiliary nozzles (051) along the axial jet to form a spray fan (084), wherein the impact point between the spray fan (084) and the inner wall of the combustion chamber (01) is offset to form two cooling rings; Step 3: The oxygen-rich fuel gas of the gunpowder igniter is injected into the combustion chamber (01) along the axis through the gunpowder igniter fuel gas channel (032), and contacts with a small amount of kerosene in the radial kerosene nozzle jet to achieve ignition.

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