A gas-liquid needle injector that uses forward and reverse swirl to enhance spray combustion and cool the head of the needle rod of the gas-liquid needle injector

Abstract

The present invention discloses a gas-liquid pintle injector with forward and reverse swirls to enhance spray combustion and head cooling, which belongs to the technical field of rocket propulsion equipment. The injector comprises a pintle rod, an inner sleeve and an outer sleeve which are coaxial and arranged in sequence on the outer circumference of the pintle rod, and is characterized in that: two radial multi-layer swirls with opposite swirl directions are arranged in the inner sleeve and the outer sleeve, the inner side of the gas phase swirl collides with the radial liquid jet at the pintle rod head to enhance the spray, and the outer side of the gas phase swirl can reduce the unevenness of the spray atomization in the circumferential direction; a small injection hole is opened on the end face of the pintle rod head to protect the pintle from being ablated; the present invention solves the problem of uneven spatial distribution of the spray morphology caused by the collision of the unidirectional swirl gas with the radial jet at the pintle head, and also solves the problem that when the radial and axial breakup distances of the jet are reduced, the spray-dense area and the subsequent spray combustion area are close to the pintle head, which easily causes ablation of the pintle head and affects the service life.

Description

Technical Field

[0001] The present application belongs to the technical field of recoverable variable flow regulating rocket propulsion equipment, and specifically relates to a gas-liquid needle injector that enhances spray combustion through positive and negative swirls and cools the head of the needle rod of the gas-liquid needle injector. Background Art

[0002] This invention relates to rocket propulsion technology. It employs a gas / liquid injection system, making it particularly suitable for long-term storage, green, ambient-temperature fuel systems (such as hydrogen peroxide / kerosene and nitrous oxide / propane). This system avoids the system complexity of cryogenic liquid oxygen fuel and meets the current development needs of low-flow rockets. The invention utilizes a gas / liquid pintle injector with multi-layer swirl-enhanced spray combustion and spray cooling at the injector head. Pintle injectors are recognized as a preferred choice for variable thrust rockets due to their simple structure, continuous flow rate adjustment, and stable combustion.

[0003] The advantage of gas / liquid injection (generally axial gas injection) over liquid / liquid injection is that the shearing effect caused by the high-speed gas injection can easily break up the liquid fuel jet. A previously authorized patent, "A gas / liquid needle injector with swirl-assisted atomization and adjustable swirl," describes its improvement over the traditional (axial) gas / (radial) liquid needle injector, effectively resolving the problem of poor spray distribution characteristics caused by excessive axial gas injection velocity in traditional gas / liquid needle injectors. Firstly, axial gas injection is swirl-injected, reducing axial momentum and increasing the spray cone angle, while also utilizing the circumferential shearing effect of the swirl to assist atomization. Secondly, axial flow channels formed by the inner and outer sleeves, respectively, achieve adjustable gas swirl by rationally distributing their respective flow rates, achieving optimal spray cone angle and atomization characteristics and simplifying the matching requirements for the structural parameter design of the injection area and injection velocity. Furthermore, the central gas core low-pressure zone formed by the gas swirl is used to draw part of the radial liquid jet into the outer sleeve, promoting breakup at the jet root and achieving gas-assisted atomization.

[0004] However, this invention still has the following deficiencies in principle design, structural design, and application design in real combustion chamber scenarios:

[0005] First, the axial swirl gas uses a single tangential hole inlet, and the swirl has only one rotation direction. When the axial length of the pintle or the axial flow path of the gas is not long enough, the swirl in the pipe is not fully developed, and the gas velocity is uneven in the circumferential direction at the annular gap outlet. As a result, the spray pattern after the gas collides with the radial jet from the pintle head becomes non-axisymmetric and non-uniform in spatial distribution, which affects the spray combustion in the combustion chamber.

[0006] Second, after using swirl gas assisted atomization, although the spray characteristics are improved, the radial and axial breakup distances of the jet are reduced, making the spray dense area and the subsequent spray combustion area close to the needle plug head, which can easily cause erosion of the needle plug head and affect the service life. Summary of the Invention

[0007] In response to the shortcomings of the existing technology, the present invention proposes a gas-liquid needle injector that enhances spray combustion through positive and negative swirls and cools the head of the needle rod of the gas-liquid needle injector. The first purpose is to solve the problem in the existing technology that the spray shape caused by the collision of the unidirectional swirl gas with the radial jet of the needle rod head presents a non-axisymmetric and non-uniform spatial distribution, and has an adverse effect on the spray combustion in the combustion chamber. The second purpose is to solve the problem that when the radial and axial breakup distances of the jet are reduced, the spray-dense area and the subsequent spray combustion area are close to the needle rod head, which easily causes erosion of the needle rod head and affects the service life.

[0008] This application adopts the following technical solutions to solve its technical problems:

[0009] A gas / liquid pintle injector is disclosed that uses forward and reverse swirls to enhance spray combustion and cool the head of the pintle rod of the gas / liquid pintle injector. The gas / liquid pintle injector is used in rocket propulsion equipment and includes a pintle rod, and an inner sleeve and an outer sleeve disposed coaxially and sequentially around the outer periphery of the pintle rod. The pintle rod is used to provide irrotational flow of the liquid, and the inner sleeve and outer sleeve are used to provide swirling flow of the gas.

[0010] Its characteristics are: two radial multi-layer swirls with opposite swirl directions are arranged in the inner sleeve and the outer sleeve, thereby forming an inner and outer layered gas phase swirl structure, the inner side of the gas phase swirl structure collides with the radial liquid jet of the pintle rod head, thereby strengthening the spray, and the outer side of the gas phase swirl structure can reduce the unevenness of the spray atomization in the circumferential direction; an ultra-small aperture injection hole is opened on the end face of the pintle rod head, and the evaporation heat absorption effect of the atomized droplets formed by the injection of the ultra-small aperture injection hole is used to protect the pintle from being ablated; the radial liquid jet of the pintle rod head is ejected from the injection holes with rectangular openings arranged in a circular array on the pintle rod head.

[0011] Furthermore, a pintle rod inner flow channel is provided at the center of the pintle rod, an inner sleeve inner flow channel is provided between the pintle rod and the inner sleeve, and an outer sleeve inner flow channel is provided between the inner sleeve and the outer sleeve. The outlet ends of the inner sleeve inner flow channel and the outer sleeve inner flow channel are at the same height, and the outlet end of the pintle rod inner flow channel extends a set distance beyond the outlet ends of the inner sleeve inner flow channel and the outer sleeve inner flow channel.

[0012] Furthermore, the outlet end of the inner flow channel of the pintle rod extends a set distance beyond the outlet ends of the inner flow channel of the inner sleeve and the outer sleeve, and the set distance is equal to the outer diameter of the pintle rod, preferably but not limited to 12 mm.

[0013] Furthermore, the gas-liquid needle injector comprises three parts, namely, a needle rod 1, an inner sleeve and an outer sleeve, in the axial direction from top to bottom; the needle rod is provided with a liquid radial inlet and a radial inlet liquid collecting chamber for providing liquid irrotational flow, and the radial inlet liquid collecting chamber is connected to the inner flow channel of the needle rod; the inner sleeve is provided with a gas positive rotation tangential inlet and a positive rotation tangential inlet gas collecting chamber for providing gas rotatory flow, and the positive rotation tangential inlet gas collecting chamber is connected to the inner flow channel of the inner sleeve on the inner side of the inner and outer layered gas cyclone structure; the outer sleeve is provided with a gas reverse rotation tangential inlet and a reverse rotation tangential inlet gas collecting chamber for providing gas rotatory flow, and the reverse rotation tangential inlet gas collecting chamber is connected to the inner flow channel of the outer sleeve on the outer side of the inner and outer layered gas cyclone structure; the needle rod and the inner sleeve, and the inner sleeve and the outer sleeve are respectively connected by flanges; the positive rotation is a rotation in a clockwise direction when viewed from a top view, and the reverse rotation is a rotation in a counterclockwise direction when viewed from a top view.

[0014] Furthermore, the gas phase swirl structure with inner and outer layers and opposite swirl directions is composed of a pintle rod, an inner sleeve, an outer sleeve, a gas forward swirl tangential inlet and a forward swirl tangential inlet gas collecting chamber opened on the inner sleeve, a gas reverse swirl tangential inlet and a reverse swirl tangential inlet gas collecting chamber opened on the outer sleeve, an inner sleeve inner flow channel between the pintle rod and the inner sleeve, and an outer sleeve inner flow channel between the inner sleeve and the outer sleeve; the tangential inlets of the gas forward swirl tangential inlet and the gas reverse swirl tangential inlet are parallel and in opposite directions.

[0015] Furthermore, the length of the inner flow channel of the pintle rod is preferably but not limited to 80-100 mm, the length of the inner flow channel of the inner sleeve is preferably but not limited to 65-75 mm, and the length of the inner flow channel of the outer sleeve is preferably but not limited to 50-60 mm.

[0016] Furthermore, the gas-liquid pintle injector adopts bipropellant injection, and the bipropellant is divided into liquid propellant A and gas propellant B; the inner flow channel of the pintle rod is connected to the supply system of liquid propellant A through the liquid radial inlet, and the inner flow channel of the inner sleeve and the inner flow channel of the outer sleeve are connected to the gas propellant through the gas forward rotating tangential inlet and the gas reverse rotating tangential inlet respectively.

[0017] Furthermore, the jet velocity of the outlet air flow of the flow channel in the inner sleeve is preferably but not limited to 150-250 m / s, the jet velocity of the outlet air flow of the flow channel in the outer sleeve is preferably but not limited to 150-250 m / s, and the liquid jet velocity of the rectangular injection hole at the outlet of the flow channel in the needle bolt rod is preferably but not limited to 20-40 m / s.

[0018] Furthermore, the end surface of the pintle rod head is provided with an injection hole with an ultra-small aperture, and the injection holes with an ultra-small aperture are evenly distributed along each set radius, and the number of the holes distributed along each radius is equal.

[0019] Furthermore, the number and diameter of the ultra-small aperture injection holes on the head end face of the pintle rod are based on the standard of not excessively consuming and affecting the mass flow rate of the liquid propellant A, while also being able to play the role of absorbing heat by droplet evaporation to protect the pintle from being ablated; the diameter of the ultra-small aperture injection holes on the head end face of the pintle rod is preferably but not limited to 0.06-0.1 mm.

[0020] Advantages and effects of the present invention

[0021] The present invention organically combines the design of two counter-directional swirls and the design of a small injection hole in the needle plug head, which are interdependent. The design of the two counter-directional swirls is used to achieve more sufficient and spatially uniform atomization as the goal, and the design of the small injection hole in the needle plug head is used to ensure that the needle plug rod head will not be burned after sufficient atomization as a guarantee for achieving the goal. This solves the problem of the spray morphology showing non-axisymmetric and non-uniform spatial distribution after the collision of the unidirectional swirl gas and the radial jet of the needle plug head in the prior art, and the adverse effect on the spray combustion in the combustion chamber. It also solves the problem that when the radial and axial breakup distances of the jet are reduced, the spray-dense area and the subsequent spray combustion area are close to the needle plug head, which easily causes the needle plug head to be burned and affects the service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a first-perspective schematic diagram of the assembly diagram of the gas-liquid needle injector of this application;

[0023] Figure 1a To assemble the first person perspective Figure 5 Schematic diagram of cross-section division;

[0024] Figure 1b1 for Figure 1a 2D diagram of the radial inlet cross section of AA liquid;

[0025] Figure 1b2 for Figure 1a 3D diagram of the radial inlet cross section of AA liquid;

[0026] Figure 1c1 for Figure 1a Two-dimensional diagram of the BB gas forward rotation tangential inlet cross section;

[0027] Figure 1c2 for Figure 1a BB gas forward rotation tangential inlet cross section three-dimensional diagram;

[0028] Figure 1d1for Figure 1a Two-dimensional diagram of the CC gas counter-rotating tangential inlet cross section;

[0029] Figure 1d2 for Figure 1a 3D diagram of CC gas counter-rotating tangential inlet cross section;

[0030] Figure 1e1 for Figure 1a DD cross-section two-dimensional diagram;

[0031] Figure 1e2 for Figure 1a DD cross-section three-dimensional diagram;

[0032] Figure 1f1 for Figure 1a EE cross-section two-dimensional diagram;

[0033] Figure 1f2 for Figure 1a EE cross-section three-dimensional diagram;

[0034] Figure 2 This is a schematic diagram of the assembly of the gas-liquid needle injector of the present application from a second perspective;

[0035] Figure 3 A schematic cross-sectional view of the gas-liquid needle injector of the present application from a first perspective;

[0036] Figure 4 A cross-sectional schematic diagram of the gas-liquid needle injector of the present application from a second viewing angle;

[0037] Figure 5 This is a schematic diagram of the injection holes with rectangular openings arranged in a circumferential array on the head of the pintle rod of the present application;

[0038] Figure 6 Schematic diagram of the ultra-small aperture injection hole on the end surface of the pintle rod of the present application;

[0039] Figure 7a This is the effect diagram of the prior art unidirectional swirl atomization;

[0040] Figure 7b This is a diagram showing the effect of the "positive" and "negative" bidirectional swirl atomization of the present invention.

[0041] In the figure: 1: needle bolt rod; 2: inner sleeve; 3: outer sleeve; 4: liquid radial inlet; 4-1: radial inlet liquid collecting chamber; 5: gas forward-spinning tangential inlet; 5-1: forward-spinning tangential inlet gas collecting chamber; 6: gas reverse-spinning tangential inlet; 6-1: reverse-spinning tangential inlet gas collecting chamber; 7: injection hole with a rectangular opening shape; 8: flow channel in the inner sleeve; 9: flow channel in the outer sleeve; 10: flow channel in the needle bolt rod; 11: injection hole with ultra-small aperture. DETAILED DESCRIPTION

[0042] Design principle of the present invention

[0043] 1. Design Difficulties of the Present Invention: The first difficulty lies in the limited length of the gas-liquid pintle injector, which cannot be infinitely long. If the gas flow path is not sufficiently long, the swirl flow cannot fully develop within the inner flow path, and collision with the radial liquid jet will result in uneven circumferential atomization distribution. A second difficulty lies in the fact that while the swirl flow assists atomization and achieves uniform atomization, it also faces the problem of premature atomization, bringing the combustion area closer to the outlet of the pintle rod 1 and causing burn damage to the pintle rod.

[0044] 2. Solve the first difficulty: the design of two swirls in opposite directions. The liquid in the pintle rod is ejected radially from the rectangular injection hole at the pintle head, and the gas is ejected axially. After the gas and liquid collide, a spray cone with a certain angle (0 to 90 degrees) is formed. If there is no swirl, the gas density is much lower than that of the liquid, resulting in a much higher gas injection velocity than the liquid, causing the momentum ratio (defined as the ratio of radial to axial momentum) to be too small. The spray shape at the pintle head will be very flat and slender (the spray cone angle is close to 90 degrees). After adding unidirectional swirl, the axial momentum of the gas is reduced, and the spray shape becomes a more reasonable spray cone (about 45-60 degrees). Although gas swirl injection promotes atomization, the swirl will also cause uneven spatial distribution of the spray in the circumferential direction. The main reason is that the length of the gas-liquid pintle injector cannot be infinitely long. If the gas flow channel is not long enough, the swirl cannot fully develop in the inner flow channel. After colliding with the radial liquid jet, it will cause uneven spatial atomization distribution in the circumferential direction. Statistically speaking, the time average of the spatial distribution of atomization is consistent, but due to the transient characteristics of the spray, combustion will oscillate at a certain moment. An additional swirl in the opposite direction is added to form a radially layered swirl structure. The inner side of the swirl contacts the liquid jet to assist atomization, similar to the existing technology, while the outer side of the swirl creates a reverse effect, making the entire spray uniform in space. Compared with the single-direction swirl of the prior art "a gas / liquid needle injector with swirl-assisted atomization and adjustable swirl degree", the inner sleeve 2 of the prior art outputs vortex-free gas and the outer sleeve 3 outputs vortexed gas. The outer sleeve is long and the inner sleeve is short. The vortexed gas of the outer sleeve merges with the vortex-free gas of the inner sleeve at the outlet of the inner sleeve, and after merging, a single-direction vortexed gas is formed, which is then ejected from the outlet end of the outer sleeve. One of the improvements of the present application is that both the inner sleeve 2 and the outer sleeve 3 output swirling gas, and the swirling directions of the two swirling gases are opposite and both enter tangentially, that is, both generate swirls but in opposite directions, wherein the swirl directions are opposite because the cutouts of the inner sleeve 2 and the outer sleeve 3 are in opposite directions. The second improvement of the present application is that the outlet ends of the inner sleeve and the outer sleeve are flush and the outlet end heights are equal. The advantage of this is that the inner swirl of the gas phase swirl structure is used to assist atomization and change the spray swirl angle, but it may cause uneven spray, that is, oscillation in a certain time period. Since the outlet ends of the outer sleeve and the inner sleeve are flush, when the inner swirl oscillates in the current plane, the outer swirl gives a swirl in the opposite direction in the same plane, the outer swirl rotates in the opposite direction while the inner swirl rotates in the forward direction, wherein the inner swirl plays the role of assisting the spray, while the outer swirl plays the role of controlling the swirl to be as uniform as possible in space.

[0045] 3. Solve the second difficulty: the design of a small injection hole at the needle head. When the gas is injected in an axial swirl, the swirl assists the atomization, and the axial breakup distance of the liquid jet is reduced, and the atomization is advanced, that is, the atomization zone and the combustion zone will be closer to the needle rod head, causing ablation of the needle rod. Therefore, the second improvement of this application is to open a very small liquid injection hole at the bottom of the needle. First, the design principle of opening a small hole: the purpose of opening a very small hole in the needle head is to allow kerosene to be sprayed out from here. Originally, kerosene was sprayed out from the rectangular injection hole 7 of the opening of the flow channel 10 in the needle rod to ensure the main atomization area. Now, spraying it out from a very small hole can play a role similar to liquid film cooling. The atomized droplets evaporate and absorb heat, which plays a protective role for the needle head. Second, the design of the number and diameter of small holes: Too few holes or too small a diameter will result in insufficient kerosene evaporation, failing to absorb heat and cool the system. Too many holes or too large a diameter will affect kerosene flow. The quantitative analysis of the number and diameter of small holes should be determined based on different operating conditions, based on how much flow absorbs how much temperature, and how much temperature reduction is required. In short, the number and diameter of small holes should be determined to minimize excessive consumption and impact on the mass flow of the liquid propellant A, while also ensuring that droplet evaporation absorbs heat and protects the pintle from ablation.

[0046] Based on the above invention principle, the present invention designs a gas-liquid needle injector that strengthens spray combustion and cools the head of the needle rod of the gas-liquid needle injector through positive and negative swirl flow. Figure 1 、 Figure 1a 、 Figure 1b1 、 Figure 1b2 、 Figure 1c1 、 Figure 1c2 、 Figure 1d1 、 Figure 1d2 、 Figure 1e1 、 Figure 1e2 、 Figure 1f1 、 Figure 1f2 、 Figure 2 、 Figure 3 、 Figure 4 、 Figure 5 、 Figure 6 、 Figure 7a 、 Figure 7b As shown, the gas-liquid pintle injector is used for rocket propulsion equipment, including a pintle rod 1, an inner sleeve 2 and an outer sleeve 3 which are coaxial and arranged in sequence on the outer periphery of the pintle rod 1, the pintle rod 1 is used to provide irrotational flow of the liquid, and the inner sleeve 2 and the outer sleeve 3 are used to provide rotatory flow of the gas.

[0047] Its characteristics are as follows: two radial multi-layer swirl structures with opposite swirl directions are arranged on the inner sleeve 2 and the outer sleeve 3, thereby forming an inner and outer layered gas phase swirl structure, the inner side of the gas phase swirl structure collides with the radial liquid jet from the head of the pintle rod 1 to strengthen the spray, and the outer side of the gas phase swirl structure reduces the unevenness of the spray atomization in the circumferential direction; an ultra-small aperture injection hole 11 is opened on the end face of the head of the pintle rod 1, and the evaporation and heat absorption effect of the droplets formed by the injection and atomization of the ultra-small aperture injection hole 11 is utilized to protect the pintle from ablation; the radial liquid jet from the head of the pintle rod 1 is ejected from the injection holes 7 with rectangular openings arranged in a circumferential array on the head of the pintle rod 1.

[0048] Furthermore, a pintle rod inner flow channel 10 is opened in the center of the pintle rod 1, an inner sleeve inner flow channel 8 is opened between the pintle rod 1 and the inner sleeve 2, and an outer sleeve inner flow channel 9 is opened between the inner sleeve 2 and the outer sleeve 3. The outlet ends of the inner sleeve inner flow channel 8 and the outer sleeve inner flow channel 9 are at the same height, and the outlet end of the pintle rod inner flow channel 10 extends a set distance beyond the outlet ends of the inner sleeve inner flow channel 8 and the outer sleeve inner flow channel 9.

[0049] Supplementary Note 1

[0050] 1) The pintle rod 1 has an axial inner flow channel 10 at its center, connected to the supply system of liquid propellant A. Its bottom is a nearly hemispherical seal and has a radial array of rectangular injection holes 7;

[0051] 2) In addition to the rectangular injection hole 7, the end face of the needle head is penetrated by a series of ultra-small aperture injection holes 11, providing a spray area with a small penetration distance and a large spray cone angle distributed near the needle head;

[0052] 3) The outer periphery of the pintle rod is connected to two coaxial sleeves with flush lower ends: inner sleeve 2 and outer sleeve 3. Both sleeves are shorter than the pintle rod 1. Both inner sleeve 2 and outer sleeve 3 are connected to a forward-swirl gas tangential inlet 5 and a reverse-swirl gas tangential inlet 6. These two inlets are connected to the gas propellant B supply system, providing two gas swirls in opposite directions.

[0053] 4) The swirl of the inner sleeve and the outer sleeve forms a layered gas phase swirl structure. The inner side of the swirl gas collides with the radial liquid jet to strengthen the spray, while the outer side of the swirl gas reduces the unevenness of the spray atomization in the circumferential direction;

[0054] Furthermore, the outlet end of the pintle rod inner flow channel 10 extends a set distance beyond the outlet ends of the inner sleeve inner flow channel 8 and the outer sleeve inner flow channel 9. The set distance is equal to the outer diameter of the pintle rod 1, preferably but not limited to 12 mm.

[0055] Furthermore, the gas-liquid needle injector axially comprises a needle rod 1, an inner sleeve 2 and an outer sleeve 3 in sequence; the needle rod 1 is provided with a liquid radial cutout 4 and a radial cutout liquid collecting chamber 4-1 for providing irrotational flow of the liquid, and the radial cutout liquid collecting chamber 4-1 is connected to the inner flow channel 10 of the needle rod; the inner sleeve 2 is provided with a gas positive swirl tangential inlet 5 and a positive swirl tangential inlet gas collecting chamber 5-1 for providing swirl flow of the gas, and the positive swirl tangential inlet gas collecting chamber 5-1 is connected to the radial multi-layer swirl structure. The outer sleeve 3 is provided with a gas counter-rotating tangential inlet 6 and a counter-rotating tangential inlet gas collecting chamber 6-1 for providing a swirling flow of gas, and the counter-rotating tangential inlet gas collecting chamber 6-1 is connected to the inner flow channel 9 of the outer sleeve outside the radial multi-layer swirling structure; the pintle rod 1 and the inner sleeve 2, and the inner sleeve 2 and the outer sleeve 3 are respectively connected by flanges; the positive rotation is a rotation in a clockwise direction when viewed from a top view, and the counter-rotation is a rotation in a counterclockwise direction when viewed from a top view.

[0056] Furthermore, the inner and outer layered gas phase swirl structure with opposite swirl directions is composed of a pintle rod 1, an inner sleeve 2, an outer sleeve 3, a gas forward swirl tangential inlet 5 and a forward swirl tangential inlet gas collecting chamber 5-1 opened on the inner sleeve 2, a gas reverse swirl tangential inlet 6 and a reverse swirl tangential inlet gas collecting chamber 6-1 opened on the outer sleeve 3, an inner sleeve inner flow channel 8 between the pintle rod 1 and the inner sleeve 2, and an outer sleeve inner flow channel 9 between the inner sleeve 2 and the outer sleeve 3; the tangential inlets of the gas forward swirl tangential inlet 5 and the gas reverse swirl tangential inlet 6 are parallel and in opposite directions.

[0057] Supplementary Note 2:

[0058] The tangential inlets of the gas forward rotating tangential inlet 5 and the gas reverse rotating tangential inlet 6 can be arranged 180 degrees symmetrically with each other, or can be arranged at other angles. The positions of the needle rod 1, the inner sleeve 2 and the outer sleeve 3 in the circumferential direction are not limited.

[0059] Furthermore, the length of the pintle rod inner channel 10 is preferably but not limited to 80-100 mm, the length of the inner sleeve inner channel 8 is preferably but not limited to 65-75 mm, and the length of the outer sleeve inner channel 9 is preferably but not limited to 50-60 mm.

[0060] Furthermore, the gas-liquid pintle injector adopts bipropellant injection, and the bipropellant is divided into liquid propellant A and gas propellant B; the inner flow channel 10 of the pintle rod is connected to the supply system of liquid propellant A through the liquid radial inlet 4, and the inner flow channel 8 of the inner sleeve and the inner flow channel 9 of the outer sleeve are connected to the gas propellant B through the gas forward tangential inlet 5 and the gas reverse tangential inlet 6 respectively.

[0061] Furthermore, the jet velocity of the outlet airflow of the inner sleeve inner flow channel 8 is preferably but not limited to 150-250 m / s, the jet velocity of the outlet airflow of the outer sleeve inner flow channel 9 is preferably but not limited to 150-250 m / s, and the liquid jet velocity of the rectangular injection hole at the outlet of the needle bolt rod inner flow channel 10 is preferably but not limited to 20-40 m / s.

[0062] Supplementary Note 3:

[0063] The propellant injection velocity of the inner sleeve 2 and outer sleeve 3 is much greater than the propellant injection velocity of the central flow channel of the pintle rod 1. When the swirl is large enough, the shearing effect of the gas phase swirl structure in the circumferential direction can promote the breakup of the radial jet at the head of the pintle rod 1, thereby reducing the axial breakup distance of the liquid jet.

[0064] Furthermore, the end face of the head of the pintle rod 1 is provided with an ultra-small aperture injection hole 11, which is evenly distributed along each set radius, and the number of the holes distributed along each radius is equal.

[0065] Furthermore, the number and diameter of the ultra-small aperture injection holes 11 on the head end face of the pintle rod 1 are based on the standard of not excessively consuming and affecting the mass flow rate of the liquid propellant A, while also being able to play the role of absorbing heat by droplet evaporation to protect the pintle from being ablated; the diameter of the ultra-small aperture injection holes 11 on the head end face of the pintle rod 1 is preferably but not limited to 0.06-0.1 mm.

[0066] Supplementary Note 4:

[0067] like Figure 7a 、 7b The following figures compare the effects of the prior art unidirectional swirl spray and the present invention's forward and reverse bidirectional swirl spray. In the prior art, a liquid jet is ejected from a rectangular nozzle opening and deflected by the unidirectional gas swirl to achieve primary atomization. If the gas swirl in the pipe is not fully developed, the gas velocity will be uneven in the circumferential direction at the annular gap outlet, which may cause the spray pattern after the gas collides with the radial jet from the needle head to exhibit non-axisymmetric and non-uniform spatial distribution, which adversely affects the spray combustion in the combustion chamber. In contrast, in the present invention, a liquid jet is ejected from a rectangular nozzle opening and deflected by the inner gas swirl to achieve primary atomization. At the same time, it is reversely deflected by the outer gas swirl to achieve secondary atomization, further promoting atomization and reducing circumferential spray unevenness. In addition, the evaporation heat absorption effect of the atomized droplets formed by the ultra-small nozzle aperture protects the needle from ablation.

[0068] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

Claims

1. A gas-liquid pintle injector that enhances spray combustion and cools the head of a pintle rod of the gas-liquid pintle injector by means of positive and negative swirls, the gas-liquid pintle injector being used for rocket propulsion equipment, comprising a pintle rod (1), an inner sleeve (2) and an outer sleeve (3) coaxially arranged in sequence on the outer periphery of the pintle rod (1), the gas-liquid pintle injector that enhances spray combustion and cools the head of the pintle rod (1) by means of positive and negative swirls, the pintle rod (1) being used to provide a non-swirl axial flow of the liquid, the inner sleeve (2) and the outer sleeve (3) being used to provide a swirl axial flow of the gas; Its characteristics are: Two radial multi-layer swirls with opposite swirl directions are arranged in the inner sleeve (2) and the outer sleeve (3), thereby forming an inner and outer layered gas phase swirl structure with opposite swirl directions. The inner side of the gas phase swirl structure collides with the radial liquid jet of the head of the needle bolt rod (1) to strengthen the spray, and the outer side of the gas phase swirl structure can reduce the unevenness of the spray atomization in the circumferential direction; an ultra-small aperture injection hole (11) is opened on the end face of the head of the needle bolt rod (1), and the evaporation heat absorption effect of the atomized droplets formed by the injection of the ultra-small aperture injection hole (11) is used to protect the needle bolt rod (1) from being ablated. The radial liquid jet of the head of the needle bolt rod (1) is ejected from the injection holes (7) with rectangular openings arranged in a circumferential array at the head of the needle bolt rod (1).

2. The gas-liquid pintle injector according to claim 1, which enhances spray combustion and cools the pintle rod head of the gas-liquid pintle injector by using forward and reverse swirls, is characterized in that: A pintle rod inner flow channel (10) is provided at the center of the pintle rod (1); an annular axial inner sleeve inner flow channel (8) is provided between the pintle rod (1) and the inner sleeve (2); an annular axial outer sleeve inner flow channel (9) is provided between the inner sleeve (2) and the outer sleeve (3); the outlet ends of the inner sleeve inner flow channel (8) and the outer sleeve inner flow channel (9) are at the same height, and the outlet end of the pintle rod inner flow channel (10) extends beyond the outlet ends of the inner sleeve inner flow channel (8) and the outer sleeve inner flow channel (9) by a set distance.

3. The gas-liquid pintle injector according to claim 2, which enhances spray combustion and cools the pintle rod head of the gas-liquid pintle injector by using forward and reverse swirls, is characterized in that: The set distance is equal to the outer diameter of the pintle rod (1).

4. The gas-liquid pintle injector according to claim 2, which enhances spray combustion and cools the pintle rod head of the gas-liquid pintle injector by using forward and reverse swirls, is characterized in that: The gas-liquid needle injector comprises three parts, axially from top to bottom, namely a needle rod (1), an inner sleeve (2) and an outer sleeve (3); the needle rod (1) is provided with a liquid radial inlet (4) for providing a non-rotating flow of liquid and a radial inlet liquid collecting chamber (4-1), the radial inlet liquid collecting chamber (4-1) being connected to an inner flow channel (10) of the needle rod; the inner sleeve (2) is provided with a gas positive-spinning tangential inlet (5) for providing a rotatory flow of gas and a positive-spinning tangential inlet gas collecting chamber ( 5-1), the forward-rotating tangential inlet gas collecting chamber (5-1) is connected to the inner flow channel (8) of the inner sleeve; the outer sleeve (3) is provided with a gas reverse-rotating tangential inlet (6) for providing a swirling flow of gas and a reverse-rotating tangential inlet gas collecting chamber (6-1), the reverse-rotating tangential inlet gas collecting chamber (6-1) is connected to the inner flow channel (9) of the outer sleeve; the pintle rod (1) and the inner sleeve (2), and the inner sleeve (2) and the outer sleeve (3) are respectively connected by flanges.

5. The gas-liquid pintle injector according to claim 4, which enhances spray combustion and cools the pintle rod head of the gas-liquid pintle injector by using forward and reverse swirls, is characterized in that: The gas phase cyclone structure with inner and outer layers and opposite cyclone directions is formed by the pintle rod (1), the inner sleeve (2), the outer sleeve (3), the gas forward cyclone tangential inlet (5) and the forward cyclone tangential inlet gas collecting chamber (5-1) provided on the inner sleeve (2), the gas reverse cyclone tangential inlet (6) and the reverse cyclone tangential inlet gas collecting chamber (6-1) provided on the outer sleeve (3), the inner sleeve inner flow channel (8) between the pintle rod (1) and the inner sleeve (2), and the outer sleeve inner flow channel (9) between the inner sleeve (2) and the outer sleeve (3); the tangential inlets of the gas forward cyclone tangential inlet (5) and the gas reverse cyclone tangential inlet (6) are parallel to each other and in opposite directions.

6. The gas-liquid pintle injector according to claim 2, which enhances spray combustion and cools the pintle rod head of the gas-liquid pintle injector by using forward and reverse swirls, is characterized in that: The length of the inner flow channel (10) of the pintle rod is 80-100 mm, the length of the inner flow channel (8) of the inner sleeve is 65-75 mm, and the length of the inner flow channel (9) of the outer sleeve is 50-60 mm.

7. The gas-liquid pintle injector according to claim 4, which enhances spray combustion and cools the pintle rod head of the gas-liquid pintle injector by using forward and reverse swirls, is characterized in that: The gas-liquid pintle injector adopts bipropellant injection, and the bipropellant is divided into liquid propellant A and gas propellant B; the inner flow channel (10) of the pintle rod is connected to the supply system of liquid propellant A through the liquid radial inlet (4), and the inner flow channel (8) of the inner sleeve and the inner flow channel (9) of the outer sleeve are connected to the gas propellant B through the gas forward tangential inlet (5) and the gas reverse tangential inlet (6), respectively.

8. The gas-liquid pintle injector according to claim 2, which enhances spray combustion and cools the pintle rod head of the gas-liquid pintle injector by using forward and reverse swirls, is characterized in that: The outlet air flow velocity of the inner flow channel (8) of the inner sleeve is 150-250 m / s, the outlet air flow velocity of the inner flow channel (9) of the outer sleeve is 150-250 m / s, and the outlet liquid velocity of the rectangular injection hole of the inner flow channel (10) of the needle bolt rod is 20-40 m / s.

9. The gas-liquid pintle injector according to claim 1, which enhances spray combustion and cools the pintle rod head of the gas-liquid pintle injector by using forward and reverse swirls, is characterized in that: The head end surface of the pintle rod (1) is provided with an ultra-small aperture injection hole (11), and the ultra-small aperture injection holes (11) are evenly distributed along each set circle with different radii, and the number of the ultra-small aperture injection holes evenly distributed along each set circle with different radii is equal to each other.

10. The gas-liquid pintle injector according to claim 1, which enhances spray combustion and cools the pintle rod head of the gas-liquid pintle injector by using forward and reverse swirl flow, is characterized in that: The number and diameter of the ultra-small-aperture injection holes (11) provided on the head end face of the pintle rod (1) are set according to the following criteria: consuming and affecting the mass flow of the liquid propellant A as little as possible, while also protecting the pintle from being ablated by absorbing heat due to evaporation of the liquid droplets; the diameter of the ultra-small-aperture injection holes (11) on the head end face of the pintle rod (1) is 0.06-0.1 mm.

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