A gas generator with uniform mixing and reliable combustion

Abstract

The application discloses a gas generator with uniform mixing and reliable combustion, which comprises a collector, a thickened first bottom, a flow-equalizing second bottom, a large-retraction nozzle unit, an inlet top cover, a body and a flow rectifier grid; the large-retraction nozzle unit is uniformly installed in the flow-equalizing second bottom, and the thickened first bottom is installed in an end port of the flow-equalizing second bottom; the inlet top cover is connected with the other end port of the flow-equalizing second bottom to form a head of the gas generator; one end of the flow-equalizing second bottom, which is provided with the thickened first bottom, is connected with one end of the body, and the other end of the body is connected with the flow rectifier grid; the collector is sleeved outside the head and the body of the gas generator to form the gas generator. The application is suitable for a two-component liquid rocket engine and is used for promoting uniform mixing of propellants, improving combustion efficiency, reducing ablation risk, enhancing working adaptability and combustion stability.

Description

Technical Field

[0001] This invention relates to a gas generator for uniformly mixed and reliably combusted gas, belonging to the field of liquid rocket engines. Background Technology

[0002] Liquid rocket engines have advantages such as high specific impulse (250-500 seconds), a wide thrust range (single engine thrust from 1 gram force to 700 tons of force), the ability to be repeatedly started, controllable thrust, and long operating time. Liquid rocket engines are mainly used for spacecraft launch, attitude correction and control, and orbital transfer. Based on their cycle type, they can be classified into gas generator cycle liquid rocket engines, staged combustion cycle liquid rocket engines, extractive cycle liquid rocket engines, and expander cycle liquid rocket engines.

[0003] Gas generators are widely used in gas generator cycle and staged combustion cycle liquid rocket engines. Their main function is to uniformly mix and reliably combust the propellant entering the gas generator according to the designed mixing ratio, converting the chemical energy of the propellant into thermal energy. The high-temperature gas generated by the combustion of the propellant drives the rotor of the turbopump to rotate, so that the propellant continuously enters the gas generator and thrust chamber, realizing the conversion of the propellant's chemical energy into mechanical energy and ensuring the reliable and stable operation of the liquid rocket engine.

[0004] The uniformity of propellant mixing and the degree of atomization within the gas generator directly affect key characteristics such as combustion efficiency, temperature uniformity of the outlet gas, and combustion stability. Therefore, ensuring uniform propellant delivery to each nozzle through a well-designed gas generator structure is crucial. Currently, gas generators used in high-thrust liquid rocket engines typically employ flow equalization rings or multiple inlet flanges to improve propellant flow uniformity within the head chamber and ensure even mixing. However, conventional flow equalization ring structures require welding to the secondary nozzle, and insufficient weld quality can lead to fuel and oxidizer cross-contamination. Gas generators with multiple inlet flanges require more piping, resulting in excessive engine weight and hindering performance improvement. Therefore, ensuring uniform propellant distribution within each nozzle while minimizing the number of welds and reducing product weight is of paramount importance for improving the safety and performance of liquid rocket engines. Summary of the Invention

[0005] The technical problem to be solved by the present invention is as follows: In view of the above problems, the present invention proposes a gas generator for uniform mixing and reliable combustion, which is suitable for bicomponent liquid rocket engines, and is used to promote uniform mixing of propellants, improve combustion efficiency, reduce the risk of ablation, and enhance operational adaptability and combustion stability.

[0006] The technical solution adopted in this invention is: a gas generator for uniform mixing and reliable combustion, comprising a collector, a thickened first base, a flow equalization second base, a large converging nozzle unit, an inlet top cover, a body, and a flow rectifier;

[0007] The large indentation nozzle unit is evenly installed in the flow equalization base 2, and the thickened base is installed in one end port of the flow equalization base 2; the inlet top cover is connected to the other end port of the flow equalization base 2 to form the gas generator head; the end of the flow equalization base 2 with the thickened base is connected to one end of the body, and the other end of the body is connected to the rectifier grid; the collector is fitted over the gas generator head and body to form the gas generator.

[0008] Furthermore, the inlet top cover is manufactured using an additive manufacturing process and includes a top cover and a first inlet flange. The top cover has a disc structure with a central hole in the center. The first inlet flange is connected to the through hole on the side of the central hole of the top cover through a first rounded corner transition structure, which is a bent pipe shape.

[0009] Furthermore, the connection between the first rounded corner transition structure of the inlet top cover and the top cover is the inlet transition section. The inlet transition section adopts a large rounded corner transition diameter structure, and the radius of the rounded corner ranges from 5mm to 30mm. The cross-section of the first rounded corner transition structure changes from a circle to an ellipse starting from the first inlet flange end.

[0010] Furthermore, a number of nozzle mounting holes are evenly distributed on the thickened base to form several independent combustion zones for the nozzles. A blind hole is set at the center of the thickened base, so that the thickness at the center of the thickened base becomes thinner, forming a thin base portion. The area around the thin base portion is the thick base portion, and the thickness of the thick base portion is ~ times the thickness of the thin base portion.

[0011] Furthermore, the collector is manufactured using additive manufacturing technology, and the second inlet flange is connected to the spherical body through a second rounded corner transition structure. The spherical body is provided with a gas generator head mounting hole and a body mounting hole, and the second inlet flange is located on the side of the spherical body.

[0012] Furthermore, the flow equalization sub-base is manufactured using additive manufacturing technology, comprising a gunpowder nozzle, a sub-base structure, and a cylindrical section; the sub-base structure and the cylindrical section are coaxial and form a single unit; the gunpowder nozzle is arranged along the central axis of the sub-base structure and the cylindrical section; an inlet top cover mounting hole is provided at the center of the sub-base structure, and several rings of nozzle unit mounting holes are evenly distributed on the sub-base structure with the gunpowder nozzle as the center, each nozzle unit mounting hole being connected to the inlet top cover mounting hole through a variable diameter inclined flow equalization hole; the variable diameter inclined flow equalization holes on the same ring have the same diameter, and starting from the innermost ring of variable diameter inclined flow equalization holes, the diameter of the variable diameter inclined flow equalization holes on different rings gradually increases; several rings of equal diameter flow equalization holes are arranged sequentially on the side wall of the cylindrical section, and the sub-base structure is installed in conjunction with the gas generator head mounting hole of the collector; the gunpowder nozzle is inserted into the central hole of the top cover of the inlet end cover.

[0013] Furthermore, the large indentation nozzle unit adopts a large indentation nozzle, and a secondary injection hole is provided on the outer nozzle; the inner nozzle of each large indentation nozzle unit is installed in conjunction with the nozzle unit mounting hole of the uniform flow base, and the outer nozzle is installed in conjunction with the nozzle mounting hole on the thickened base.

[0014] Furthermore, the rectifier grid is manufactured using additive manufacturing technology. The rectifier surface has a spherical configuration, with several rings of spherical radial flow equalization holes evenly distributed along the sphere diameter direction. The spherical radial flow equalization holes on the same ring have the same radius, and rounded corner structures are provided upstream and downstream of the spherical radial flow equalization holes. With the center point of the rectifier grid as the center, the radii of the spherical radial flow equalization control rings on odd-numbered rings are the same, the radii of the spherical radial flow equalization control rings on even-numbered rings are the same, and the radii of the spherical radial flow equalization control rings on adjacent rings are different.

[0015] Furthermore, the collector, thickened first base, flow equalization second base, body and rectifier grid are coaxial.

[0016] Furthermore, the propellant flows through the second rounded corner transition structure of the collector and the first rounded corner transition structure of the inlet top cover into the gas generator, and then sequentially enters the major indentation nozzle units through the variable diameter inclined flow equalization hole and the equal diameter flow equalization hole of the flow equalization two bottoms.

[0017] The propellant undergoes primary mixing and combustion in the primary mixing and combustion zone of the primary mixing and combustion zone. The combustion gas after primary mixing and combustion, along with the propellant flowing through the secondary injection hole of the outer nozzle, enters the independent combustion zone of the thickened bottom nozzle for afterburning. During ignition, the combustion gas entering the igniter from the uniform flow two-bottom propellant nozzle first ignites the primary mixing and combustion zone of ...

[0018] The combusted gases reach the rectifier grid downstream of the body.

[0019] The advantages of this invention compared to the prior art are:

[0020] (1) The present invention proposes a novel gas generator structure, which consists of an integrated flange and collector structure, a flow equalization double bottom with a multi-hole flow equalization structure, a nozzle unit with a large indentation structure, a thickened bottom plate and a ball diameter variable diameter large rounded corner rectifier grid, etc.

[0021] (2) This invention designs a gas generator suitable for uniform and reliable combustion in bicomponent liquid rocket engines. It adopts additive manufacturing process for integrated production, and the flow equalization structure is more reasonable. This reduces the number of welds and parts, improves the propellant flowability, and enhances the product's pressure resistance and operational reliability. The main combustion zone of each injection unit can be protected by propellant cooling. All injection units are divided into zones for combustion, which improves the gas generator's operational safety and adaptability to operating conditions. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of a gas generator structure;

[0023] Figure 2 This is a schematic diagram of the collector structure;

[0024] Figure 3 A schematic diagram of the thickened base structure;

[0025] Figure 4 This is a schematic diagram of a uniform flow double-bottom structure;

[0026] Figure 5 This is a schematic diagram of the structure of a large-recession nozzle unit;

[0027] Figure 6 This is a schematic diagram of the entrance roof structure;

[0028] Figure 7 This is a schematic diagram of the rectifier grid structure.

[0029] In the diagram: 1. Collector; 2. Thickened first base; 3. Flow equalization second base; 4. Large indentation nozzle unit; 5. Inlet top cover; 6. Body; 7. Rectifier grid. Detailed Implementation

[0030] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0031] like Figure 1 As shown, the gas generator for uniform mixing and reliable combustion of the present invention mainly consists of a collector 1, a thickened first base 2, a flow equalization second base 3, a large converging nozzle unit 4, an inlet top cover 5, and a body 6.

[0032] The large indentation nozzle unit 4 is evenly installed in the flow equalization secondary base 3, and the thickened primary base 2 is installed inside one end port of the flow equalization secondary base 3; the inlet top cover 5 is connected to the other end port of the flow equalization secondary base 3 to form the gas generator head; the end of the flow equalization secondary base 3 with the thickened primary base 2 is connected to one end of the body 6, and the other end of the body 6 is connected to the rectifier grid 7; the collector 1 is fitted over the gas generator head and the body 6 to form the gas generator.

[0033] like Figure 6 The inlet cover 5 shown includes a cover and a first inlet flange. The cover is a disc structure with a central hole. The first inlet flange is connected to a through hole on the side of the central hole of the cover via a first rounded corner transition structure 51, which is a bent pipe shape. The connection between the first rounded corner transition structure 51 and the cover is the inlet transition section. The inlet transition section adopts a large rounded corner transition diameter-changing structure 52, with the radius of the rounded corner ranging from 5mm to 30mm. The cross-section of the first rounded corner transition structure 51 changes from a circle to an ellipse starting from the first inlet flange end.

[0034] like Figure 3 As shown, several nozzle mounting holes are evenly distributed on the thickened base 2 to form several independent combustion zones 21 for the nozzles. A blind hole is set at the center of the thickened base 2, so that the thickness at the center of the thickened base becomes thinner, forming a thin base part. The area around the thin base part is the thick base part, and the thickness of the thick base part is 2 to 8 times the thickness of the thin base part.

[0035] like Figure 2 As shown, the second inlet flange 11 of the collector 1 is connected to the spherical body 12 through the second rounded corner transition structure 13. The spherical body 12 is provided with a gas generator head mounting hole and a body mounting hole, and the second inlet flange 11 is provided on the side of the spherical body 12.

[0036] like Figure 4 As shown, the flow equalization double bottom 3 includes a gunpowder nozzle, a double bottom structure, and a cylindrical section; the double bottom structure and the cylindrical section are coaxial and form an integral structure; the gunpowder nozzle is arranged along the central axis of the double bottom structure and the cylindrical section; an inlet top cover mounting hole is provided at the center of the double bottom structure, and several rings of nozzle unit mounting holes are evenly distributed on the double bottom structure with the gunpowder nozzle as the center. Each nozzle unit mounting hole is connected to the inlet top cover mounting hole through a variable diameter inclined flow equalization hole 31; the variable diameter inclined flow equalization holes 31 located on the same ring have the same diameter, and starting from the innermost ring of variable diameter inclined flow equalization holes 31 located on different rings, the diameter of the variable diameter inclined flow equalization holes 31 gradually increases; several rings of equal diameter flow equalization holes 32 are arranged sequentially on the side wall of the cylindrical section, and the double bottom structure is installed in conjunction with the gas generator head mounting hole of the collector 1; the gunpowder nozzle is inserted into the center hole of the top cover of the inlet end cover 5.

[0037] like Figure 5As shown, the large indentation nozzle unit 4 adopts a large indentation nozzle, and a secondary injection hole 41 is provided on the outer nozzle 43; the inner nozzle 42 of each large indentation nozzle unit 4 is installed in conjunction with the nozzle unit mounting hole of the equalizing base 3, and the outer nozzle 43 is installed in conjunction with the nozzle mounting hole on the thickened base 2.

[0038] like Figure 7 As shown, the rectifying surface of the rectifier grid 7 is spherical, with several rings of spherical radial flow equalization holes 71 evenly distributed along the diameter of the sphere. The spherical radial flow equalization holes 71 on the same ring have the same radius. Rounded corner structures 72 are provided upstream and downstream of the spherical radial flow equalization holes 71. With the center point of the rectifier grid 7 as the center, the radius of each ring of spherical radial flow equalization control 71 on the odd-numbered rings is the same, the radius of each ring of spherical radial flow equalization control 71 on the even-numbered rings is the same, and the radius of the spherical radial flow equalization control 71 on adjacent rings is different.

[0039] After installation, the collector 1, the thickened base 2, the flow equalization base 3, the body 6, and the rectifier grid 7 are coaxial.

[0040] The inlet top cover 5 is produced in an integrated manner through additive manufacturing, which integrates the inlet flange and the top cover into one piece, reducing the number of welds while improving the flowability of propellant.

[0041] The thickened bottom 2 inner ring is thinner, which facilitates reliable ignition of the inner ring nozzle during the ignition process. The injection units of the other outer nozzles are all separated into independent combustion zones by the thickened bottom, which helps to improve the combustion stability of the propellant.

[0042] The aforementioned collector 1 is manufactured as a single unit using additive manufacturing technology, which integrates the inlet flange and the collector 1 into one unit. Compared with the solution of processing parts separately and then welding them, this eliminates the weld between the inlet flange and the collector 1, reduces the product weight, and improves the product's pressure-bearing performance.

[0043] The inlet transition section of the collector 1 adopts a large rounded corner transition diameter structure, which makes the propellant flow smoothly during the process of entering the gas generator and reduces the possibility of local turbulence.

[0044] The aforementioned flow equalization double base 3 is produced using additive manufacturing technology, replacing the double base, flow equalization ring and ignition tube in the traditional solution, reducing the number of products and welds, improving product quality and reliability, promoting uniform fluid mixing, and at the same time reducing the head cavity volume and reducing the aftereffect impulse.

[0045] The large indentation nozzle unit adopts a large indentation nozzle and has a secondary injection structure. While ensuring the reliable start-up and operation of the gas generator, it can meet the system's requirements for the working mixture ratio of the combustion device. At the same time, it can use propellant to cool the nozzle wall in the indentation zone, thereby improving the quality and reliability of the gas generator.

[0046] The rectifier grid 7 is manufactured in one piece using additive manufacturing process. The rectifier surface has a spherical configuration with 8 rings of spherical radial flow equalization holes evenly distributed along the diameter of the sphere. All flow equalization holes in each ring have the same radius, and the inner diameters of the flow equalization holes in each ring are staggered, which helps to offset the frequency and avoid the occurrence of combustion instability. Furthermore, rounded corner structures are designed upstream and downstream of the spherical radial flow equalization holes to facilitate the uniform flow of fluid and reduce the flow resistance characteristics of the rectifier grid 7.

[0047] First, the nozzle assembly is installed onto the equalization base 3, and a base structure is installed. The nozzle assembly, equalization base 3, and base are then brazed together. Next, the inlet top cover 5 is welded to the equalization base 3 using electron beam welding to obtain the gas generator head. The gas generator head is connected to the body 6, and the body 6 is connected to the rectifier grid 7 using electron beam welding. Finally, the collector 1 is welded to the head and body 6 respectively using electron beam welding to form the final state of the gas generator.

[0048] The working method is as follows:

[0049] The propellant (specific oxidizer or fuel selected based on the product's oxygen-rich or fuel-rich characteristics) flows through the rounded transition structure and variable diameter transition structure of the collector 1 and the inlet top cover 5, respectively, and enters the oxidizer / fuel chamber. It then sequentially passes through the variable diameter inclined flow equalization orifice and multiple rows of equal diameter flow equalization orifices of the equalization bottom 3 before entering the nozzle. The propellant undergoes primary mixing and combustion in the large-recession combustion zone 44 of the large-recession nozzle unit 4. At this time, the propellant mixing ratio can be selected to facilitate starting and combustion, i.e., the propellant mixing ratio is close to the equivalence mixing ratio. Since the outer nozzle wall is in contact with the cryogenic propellant, it provides a certain cooling protection for the gas generator structure. After primary mixing and combustion, the gas and propellant flowing through the secondary injection orifice of the outer nozzle enter the independent combustion zone 21 of the thickened bottom 2 for afterburning. At this time, the gas generator is in the mixing ratio condition required by the engine system. The structure of the combustion zone ensures that the combustion processes between the injection units are independent, avoiding instability caused by combustion coupling between different injection units. During ignition, the high-temperature gas from the igniter first ignites the nozzles near the innermost thin-bottom structure. The thin-bottom structure design is beneficial for the ignition of the gas generator and can form a stable coarse flame at the thin-bottom position, facilitating reliable start-up and stable combustion of the entire gas generator. After combustion, the high-temperature gas reaches the downstream spherical rectifier grid 7 structure of the body 6. This structure is spherical in shape, with 8 rings of spherical radial flow equalization holes evenly distributed along the spherical diameter. All flow equalization holes in each ring have the same radius, and the inner diameters of the flow equalization holes in each ring are staggered, which helps to offset the frequency and avoid combustion instability. Furthermore, rounded corner structures are designed upstream and downstream of the spherical radial flow equalization holes, which facilitates uniform mixing and high-speed passage of the gas, while reducing the flow resistance characteristics of the rectifier grid 7.

[0050] The parts of this invention not described in detail are well-known to those skilled in the art.

Claims

1. A gas generator for uniformly mixed and reliably combusted gas, characterized in that, It includes a collector (1), a thickened first base (2), a flow equalization second base (3), a large indentation nozzle unit (4), an inlet top cover (5), a body (6), and a flow rectifier (7); The large indentation nozzle unit (4) is evenly installed in the flow equalization base (3), and the thickened base (2) is installed in one end port of the flow equalization base (3); the inlet top cover (5) is connected to the other end port of the flow equalization base (3) to form the gas generator head; the end of the flow equalization base (3) with the thickened base (2) is connected to one end of the body (6), and the other end of the body (6) is connected to the rectifier grid (7); the collector (1) is fitted on the outside of the gas generator head and the body (6) to form the gas generator; The flow equalization double bottom (3) is made by additive manufacturing process and includes a gunpowder nozzle, a double bottom structure and a cylindrical section; the double bottom structure and the cylindrical section are coaxial and are an integral structure; the gunpowder nozzle is set along the central axis of the double bottom structure and the cylindrical section; the center of the double bottom structure is provided with an inlet top cover mounting hole, and several rings of nozzle unit mounting holes are evenly distributed on the double bottom structure with the gunpowder nozzle as the center. Each nozzle unit mounting hole is connected to the inlet top cover mounting hole through a variable diameter inclined flow equalization hole (31); the variable diameter inclined flow equalization holes (31) located on the same ring have the same diameter. Starting from the innermost ring of variable diameter inclined flow equalization holes (31), the diameter of the variable diameter inclined flow equalization holes (31) located on different rings gradually increases; several rings of equal diameter flow equalization holes (32) are arranged in sequence on the side wall of the cylindrical section. The double bottom structure is installed in conjunction with the gas generator head mounting hole of the collector (1); the gunpowder nozzle is inserted into the center hole of the top cover of the inlet end cover (5).

2. The gas generator for uniformly mixed and reliably combusting gas according to claim 1, characterized in that, The inlet top cover (5) is made by additive manufacturing process and includes a top cover and a first inlet flange. The top cover is a disc structure with a central hole in the center. The first inlet flange is connected to the through hole on the side of the central hole of the top cover through a first rounded corner transition structure (51). The first rounded corner transition structure (51) is a bent pipe.

3. A gas generator for uniformly mixed and reliably combusted gas according to claim 2, characterized in that, The connection between the first rounded corner transition structure (51) of the inlet top cover (5) and the top cover is the inlet transition section. The inlet transition section adopts a large rounded corner transition diameter change structure (52). The radius of the rounded corner is in the range of 5mm~30mm. The cross-section of the first rounded corner transition structure (51) changes from a circle to an ellipse starting from the first inlet flange end.

4. A gas generator for uniformly mixed and reliably combusting gas according to claim 3, characterized in that, The thickened base (2) has several nozzle mounting holes evenly distributed on it, forming several independent combustion zones (21) for the nozzles. A blind hole is set at the center of the thickened base (2), so that the thickness at the center of the thickened base becomes thinner, forming a thin base part. The area around the thin base part is the thick base part, and the thickness of the thick base part is 2 to 8 times the thickness of the thin base part.

5. A gas generator for uniformly mixed and reliably combusting gas according to claim 4, characterized in that, The collector (1) is made by additive manufacturing process. The second inlet flange (11) and the spherical body (12) are connected by a second rounded corner transition structure (13). The spherical body (12) is provided with a gas generator head mounting hole and a body mounting hole. The second inlet flange (11) is located on the side of the spherical body (12).

6. A gas generator for uniformly mixed and reliably combusting gas according to claim 5, characterized in that, The large indentation nozzle unit (4) adopts a large indentation nozzle, and a secondary injection hole (41) is provided on the outer nozzle (43); the inner nozzle (42) of each large indentation nozzle unit (4) is installed in conjunction with the nozzle unit mounting hole of the equal flow base (3), and the outer nozzle (43) is installed in conjunction with the nozzle mounting hole on the thickened base (2).

7. A gas generator for uniformly mixed and reliably combusting gas according to claim 6, characterized in that, The rectifier grid (7) is made by additive manufacturing process. The rectifier surface is spherical and has several rings of spherical radial flow equalization holes (71) evenly distributed along the spherical diameter direction. The spherical radial flow equalization holes (71) on the same ring have the same radius. Rounded corner structures (72) are provided upstream and downstream of the spherical radial flow equalization holes (71). With the center point of the rectifier grid (7) as the center, the spherical radial flow equalization holes (71) on the odd-numbered rings have the same radius, the spherical radial flow equalization holes (71) on the even-numbered rings have the same radius, and the spherical radial flow equalization holes (71) on adjacent rings have different radii.

8. A gas generator for uniformly mixed and reliably combusting gas according to claim 7, characterized in that, The collector (1), thickened first base (2), flow equalization second base (3), body (6) and rectifier grid (7) are coaxial.

9. A gas generator for uniformly mixed and reliably combusting gas according to any one of claims 1 to 8, characterized in that, The propellant flows through the second rounded transition structure (13) of the collector (1) and the first rounded transition structure of the inlet top cover (5) into the gas generator, and then enters the major indentation nozzle units (4) through the variable diameter inclined flow equalization hole (31) and the equal diameter flow equalization hole (32) of the flow equalization bottom (3). The propellant undergoes primary mixing and combustion in the primary mixing combustion zone of the primary mixing nozzle unit (4). The gas after primary mixing and combustion, along with the propellant flowing through the secondary injection hole (41) of the outer nozzle (43), enters the independent combustion zone (21) of the thickened bottom (2) nozzle for secondary combustion. During ignition, the gas entering the igniter from the propellant nozzle of the equal flow bottom (3) first ignites the primary mixing combustion zone of the primary mixing nozzle unit (4) near the innermost thin bottom structure. The combusted gas reaches the rectifier grid (7) downstream of the body (6).

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