An overexpansion type wing tip jet gas generator without compressed air inlet

Abstract

This invention relates to an outward-expanding wingtip jet gas generator without a compressed air inlet, comprising a gas generator housing, a gas generator cavity, a propellant delivery pipe, a high-temperature exhaust gas inlet pipe, and a gas outlet. The gas generator cavity is located in the head region within the gas generator housing. The propellant delivery pipe is positioned at the center of the front wall of the gas generator cavity. The gas generator housing gradually expands from bottom to top. The high-temperature exhaust gas inlet pipe is arranged in a multi-pipe configuration along the circumference of the gas generator housing and communicates with the gas generator cavity. No compressed air inlet is located at the bottom of the gas generator housing. This invention solves the technical problems of high exhaust resistance, uneven circumferential mixing, and poor downstream matching in existing gas generators used in wingtip jet applications by employing a gradually expanding housing channel combined with a circumferential multi-pipe high-temperature exhaust gas inlet configuration.

Description

Technical Field

[0001] This invention relates to the field of gas generator design technology, and more specifically to an outwardly expanding wingtip jet gas generator that uses a propellant and can be used to drive rotor wingtip jets. Background Technology

[0002] The wingtip jet autorotor aero propulsion system utilizes the high-speed exhaust gas ejected from the rotor tip nozzle to generate a reaction torque, thereby driving the rotor to rotate and fly. The gas generator in this system heats the propellant with high-temperature exhaust gas to produce high-temperature, high-pressure gas, which is then delivered to the rotor tip nozzle via a gas pipeline to achieve rotor drive during the vertical takeoff and landing hovering phase.

[0003] In this application scenario, the gas generator needs to efficiently convert the energy of high-temperature exhaust gas into the heat required for propellant decomposition within a limited hub installation space, and generate uniform high-temperature, high-pressure gas. Existing gas generator structures often face the following technical challenges when applied to this scenario: On the one hand, the use of a convergent shell to maintain combustion zone pressure results in a limited gas outlet cross-sectional area, increased exhaust resistance, and poor aerodynamic matching with the downstream expanding gas pipeline; on the other hand, while the auxiliary gas introduced to simplify the gas path can cool and protect the shell, it also increases the complexity of the gas path and the system weight. Furthermore, the introduction of the auxiliary gas dilutes the high-temperature exhaust gas, reducing its heating and catalytic efficiency for the propellant. In addition, if the high-temperature exhaust gas is introduced using a single pipe or a non-uniformly distributed method, it is difficult to quickly form a uniform temperature field in the circumferential direction, leading to differences in the gas parameters delivered downstream.

[0004] Therefore, it is necessary to provide a new type of gas generator structure that optimizes the shell configuration and air intake method in a coordinated manner without introducing auxiliary compressed air, so as to reduce gas exhaust resistance, improve circumferential mixing uniformity, and improve compatibility with downstream gas pipelines. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention aims to provide an outward-expanding wingtip jet gas generator without compressed air inlet. By adopting a gradually expanding shell channel and a circumferential multi-pipe high-temperature exhaust gas inlet method, it solves the technical problems of existing gas generators in wingtip jet applications, such as high exhaust resistance, uneven circumferential mixing, and poor downstream matching.

[0006] The present invention is achieved through the following technical solution.

[0007] An outward-expanding wingtip jet gas generator without a compressed air inlet includes a gas generator housing, a gas generator cavity, a propellant delivery pipe, a high-temperature exhaust gas inlet pipe, and a gas outlet. The gas generator cavity is located in the head region within the gas generator housing. The propellant delivery pipe is positioned at the center of the front wall of the gas generator cavity. The gas generator housing gradually expands from bottom to top, with the bottom cross-sectional area being smaller than the top cross-sectional area. The gas outlet is located at the top of the gas generator housing. The high-temperature exhaust gas inlet pipe is arranged in a multi-pipe configuration along the circumference of the gas generator housing, passing through the side wall of the gas generator housing and reaching the side wall of the gas generator cavity, where it communicates with the gas generator cavity. No compressed air inlet is located at the bottom of the gas generator housing.

[0008] Furthermore, the gradually expanding semi-cone angle of the gas generator housing is 5°~25°.

[0009] Furthermore, the high-temperature exhaust gas inlet pipe is provided with at least two branch pipes along the circumference of the gas generator housing. Each branch pipe is introduced radially and reaches the side wall of the gas generator cavity, communicating with the gas generator cavity.

[0010] Furthermore, an annular gap is formed between the gas generator housing and the gas generator inner cavity, and the annular gap is filled with heat insulation material or arranged with cooling channels.

[0011] Furthermore, the propellant delivery pipe is used to deliver the propellant, and the propellant delivery pipe is equipped with a flow control valve. The propellant is high-concentration hydrogen peroxide or a propellant mixture mainly composed of high-concentration hydrogen peroxide.

[0012] Furthermore, the ratio of the cross-sectional area of ​​the gas outlet to the cross-sectional area of ​​the bottom of the casing is 1.5 to 3.5:1.

[0013] Furthermore, the ratio of the outlet diameter of the gas generator inner cavity (2) to the top outlet diameter of the gas generator housing (1) is 0.55 to 0.70:1.

[0014] Furthermore, the ratio of the outlet diameter of the gas generator inner cavity (2) to the top outlet diameter of the gas generator housing (1) is 0.60 to 0.65:1.

[0015] Furthermore, the ratio of the outlet cross-sectional area of ​​the gas generator inner cavity to the outlet cross-sectional area of ​​the top of the gas generator housing is 0.30 to 0.50:1; preferably, the ratio of the outlet cross-sectional area of ​​the gas generator inner cavity to the outlet cross-sectional area of ​​the top of the gas generator housing is 0.36 to 0.43:1.

[0016] The working process of this invention is as follows: The gas generator has two inputs. The first input is high-temperature exhaust gas, which enters the side wall area of ​​the inner cavity of the gas generator through the high-temperature exhaust gas inlet pipe to heat the catalytic propellant. The second input is propellant, which is sent to the central reaction zone at the head of the inner cavity of the gas generator through the propellant delivery pipe. Under the action of the high-temperature exhaust gas, it releases heat and vaporizes to form a high-temperature and high-pressure mixture, which is discharged from the gas outlet and sent to the downstream wingtip nozzle through the gas delivery pipeline.

[0017] Compared with the prior art, the advantages of the present invention are:

[0018] 1. Simplified gas system and reduced structural weight: Eliminating the compressed air inlet eliminates the need for compressed air circuits and related control accessories, simplifying the system structure and reducing the weight of the gas generator, making it particularly suitable for weight-sensitive aircraft applications.

[0019] 2. Reduce gas discharge resistance and improve jet efficiency: The gradually expanding shell allows the gas to have a gradually increasing flow cross-sectional area in the flow direction, which enables the gas to expand naturally, significantly reducing the flow resistance discharged from the gas outlet, reducing the total pressure loss, and facilitating the smooth entry of gas into the downstream gas pipeline.

[0020] 3. Extending the residence time of the gas and promoting full heat exchange: The gas flow velocity in the gradually expanding channel gradually decreases along the flow direction, which prolongs the residence time of the high-temperature exhaust gas and the propellant in the inner cavity of the gas generator. This is conducive to full heat exchange and uniform mixing between the two, making the propellant decomposition reaction more complete and improving the gas production efficiency of the gas generator.

[0021] 4. Improve circumferential mixing uniformity: Multiple high-temperature exhaust gas inlet pipes are evenly distributed along the circumference, allowing the high-temperature exhaust gas to enter the gas generator cavity uniformly in the circumferential direction. This enables rapid and uniform heat exchange and mixing with the propellant sprayed from the central area, effectively avoiding the circumferential temperature unevenness that may be caused by single-pipe air intake and ensuring the consistency of gas parameters delivered downstream.

[0022] 5. Optimized insulation and cooling space: The annular gap between the gradually expanding shell and the gas generator cavity provides more space for filling lightweight and efficient insulation materials or arranging regenerative cooling channels, which helps to further reduce the structural weight while meeting thermal protection requirements.

[0023] 6. Improve downstream aerodynamic matching: The gradually expanding outlet has a large cross-sectional area, which can be smoothly connected with the downstream expanding gas transmission pipeline, reducing or eliminating the transition connection section and reducing flow loss.

[0024] 7. Achieving synergistic optimization effects that are difficult to achieve with a single feature change: This invention combines a gradually expanding shell, the elimination of the compressed air inlet, and circumferentially distributed multi-pipe direct air intake, producing a synergistic effect that cannot be achieved with a single feature change. After eliminating the compressed air inlet, if a traditional contracting shell is still used, the gas exhaust resistance increases sharply, and it is difficult to achieve circumferential uniform mixing in a limited space with a single-pipe air intake; while simply changing the shell to a gradually expanding shape but retaining a single-pipe vertical air intake, the high-temperature exhaust gas is prone to forming wall separation in the expansion channel, which actually reduces the temperature of the central reaction zone.

[0025] 8. Matching of Inner Cavity Outlet and Top Outlet Dimensions: The ratio of the outlet diameter of the gas generator's inner cavity to the outlet diameter of the gas generator's top outlet is 0.55–0.70:1, correspondingly, the ratio of the cross-sectional area of ​​the gas generator's inner cavity outlet to the cross-sectional area of ​​the gas generator's top outlet is approximately 0.30–0.50:1; preferably, the ratio is 0.60–0.65:1, correspondingly, the ratio is approximately 0.36–0.43:1. This dimensional matching ensures a reasonable expansion transition relationship between the gas generator's inner cavity outlet and the gas outlet at the top of the gas generator's shell, reducing local pressure peaks near the inner cavity outlet, making the internal pressure distribution of the gas generator more uniform, thereby reducing flow losses and improving the gas expansion process. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the structure of the present invention;

[0027] Figure 2 This is a schematic diagram of the internal structure of the present invention;

[0028] Figure 3 This is a cross-sectional view of the present invention;

[0029] Figure 4 Comparison of total internal pressure cloud diagrams of gas generators under different internal cavity outlet diameters;

[0030] In the diagram: 1. Gas generator housing; 2. Gas generator inner cavity; 3. Propellant delivery pipe; 4. High-temperature exhaust gas inlet pipe; 5. Gas outlet; 6. Annular gap. Detailed Implementation

[0031] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but this is not intended to limit the scope of the invention.

[0032] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] Example 1

[0034] like Figures 1 to 3 As shown, an outward-expanding wingtip jet gas generator without compressed air inlet includes a gas generator housing 1, a gas generator inner cavity 2, a propellant delivery pipe 3, a high-temperature exhaust gas inlet pipe 4, and a gas outlet 5.

[0035] The gas generator inner cavity 2 is located in the head region within the gas generator housing 1. The propellant delivery pipe 3 is located at the center of the front wall of the gas generator inner cavity 2.

[0036] The gas generator housing 1 is gradually expanding from bottom to top, and the gas outlet 5 is located at the top of the gas generator housing 1. The cross-sectional area of ​​the gas outlet 5 is larger than the cross-sectional area of ​​the bottom of the gas generator housing 1. The semi-cone angle of the gradually expanding gas generator housing 1 is 12°, and the ratio of the cross-sectional area of ​​the gas outlet 5 to the cross-sectional area of ​​the bottom of the gas generator housing 1 is 2.0:1.

[0037] The high-temperature exhaust gas inlet pipe 4 is evenly distributed in the circumference of the gas generator housing 1 in the form of four branch pipes. Each branch pipe passes through the side wall of the gas generator housing 1 radially and reaches the side wall of the gas generator inner cavity 2. The high-temperature exhaust gas inlet pipe 4 is connected to the gas generator inner cavity 2.

[0038] An annular gap 6 is formed between the gas generator housing 1 and the gas generator inner cavity 2. The annular gap 6 is filled with aerogel composite thermal insulation material. The annular gap 6 can also serve as a cooling channel or a space for installing a thermal insulation layer. The filling material or the arrangement of cooling medium can be selected according to the actual working conditions.

[0039] The propellant is preferably high-concentration hydrogen peroxide, but other liquid propellants capable of decomposing and generating high-temperature combustion gases under the action of high-temperature exhaust gases may also be used. The propellant delivery pipe 3 is equipped with a flow control valve.

[0040] The gas generator housing 1 does not have a compressed air inlet at the bottom.

[0041] During operation, the high-temperature exhaust gas enters the side wall area of ​​the gas generator cavity 2 symmetrically along the circumference through the four evenly distributed branch pipes of the high-temperature exhaust gas inlet pipe 4, and is uniformly heated and catalyzed in the circumferential direction; the propellant is sent to the central reaction zone at the head of the gas generator cavity 2 through the propellant delivery pipe 3, and is released and vaporized under the action of the high-temperature exhaust gas to form a high-temperature and high-pressure mixture, which is discharged from the gas outlet 5.

[0042] Example 2

[0043] Unlike Embodiment 1, in this embodiment, the gradually expanding semi-cone angle of the gas generator housing 1 is 18°, and the ratio of the cross-sectional area of ​​the gas outlet 5 to the cross-sectional area of ​​the bottom of the housing is 3.0:1. The high-temperature exhaust gas inlet pipe 4 is evenly distributed along the circumference of the gas generator housing 1 in the form of six branch pipes. A greater number of branch pipes helps to improve the uniformity of the high-temperature exhaust gas distribution in the circumferential direction and improve the heating consistency of the central reaction zone, making it particularly suitable for operating conditions where large-diameter rotors have high requirements for the consistency of downstream gas pipeline flow.

[0044] Example 3

[0045] To verify the influence of the gas generator's internal outlet size on the flow field characteristics, CFD numerical simulation was used to analyze the internal flow field of the gas generator under different internal outlet sizes. While keeping the gas generator shell size, high-temperature exhaust gas inlet parameters, and boundary conditions consistent, only the gas generator's internal outlet size was changed, and four calculation models (Case 1 to Case 4) were established. The parameters of each model are shown in Table 1.

[0046] Table 1. Parameters of different internal cavity outlet dimensions

[0047] Case 1 25 50 0.50 0.25 Case 2 27.5 50 0.55 0.30 Case 3 31.5 50 0.63 0.40 Case 4 35 50 0.70 0.49

[0048] like Figure 4 As shown, with the gradual increase in the outlet size of the gas generator cavity, the high-pressure region near the outlet gradually weakens, and the flow field distribution tends to become more uniform. Specifically, Case 1, due to its smaller outlet size, exhibits a significant local high-pressure region near the outlet, leading to increased flow resistance. As the outlet size increases, the local pressure peak gradually decreases, and the high-pressure accumulation phenomenon is improved. Simulation results indicate that the outlet size of the gas generator cavity has a significant impact on the gas expansion process; appropriately selecting the outlet size is beneficial for reducing flow losses and improving the flow uniformity of the gas in the diffuser channel. According to... Figure 4Simulation results show that when the ratio of the diameter of the gas generator's inner cavity outlet to the diameter of the top outlet of the casing is less than 0.55:1, a significant local high-pressure area is easily formed near the inner cavity outlet. When the ratio is in the range of 0.55 to 0.70:1, the pressure distribution inside the gas generator is more uniform, and the local pressure peak is significantly reduced. Among them, Case 3 has the best pressure distribution uniformity with a diameter ratio of 0.63, which is in the range of 0.60 to 0.65.

[0049] Although the present invention has been described in detail above with general descriptions and specific embodiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A wing tip jet gas generator of the outer expansion type without compressed air intake, comprising a gas generator housing (1), a gas generator inner cavity (2), a propellant delivery pipe (3), a high temperature exhaust gas intake pipe (4) and a gas outlet (5), said gas generator inner cavity (2) being arranged in the head region of said gas generator housing (1), said propellant delivery pipe (3) being arranged in the center of the front wall of said gas generator inner cavity (2), characterized in that, The gas generator housing (1) is gradually expanding from bottom to top. The bottom cross-sectional area of ​​the gas generator housing (1) is smaller than the top cross-sectional area. The gas outlet (5) is located at the top of the gas generator housing (1). The high-temperature exhaust gas inlet pipe (4) is arranged in a multi-pipe manner along the circumference of the gas generator housing (1). The high-temperature exhaust gas inlet pipe (4) passes through the side wall of the gas generator housing (1) and reaches the side wall of the gas generator inner cavity (2) and communicates with the gas generator inner cavity (2). The gas generator housing (1) does not have a compressed air inlet at the bottom.

2. The outward-expanding wingtip jet gas generator without compressed air inlet according to claim 1, characterized in that, The gradually expanding semi-cone angle of the gas generator housing (1) is 5°~25°.

3. The outward-expanding wingtip jet gas generator without compressed air inlet according to claim 1, characterized in that, At least two branch pipes are evenly arranged around the gas generator housing (1) in the high-temperature exhaust gas inlet pipe. Each branch pipe is introduced radially and reaches the side wall of the gas generator cavity (2) and communicates with the gas generator cavity (2).

4. The outward-expanding wingtip jet gas generator without compressed air inlet according to claim 1, characterized in that, An annular gap is formed between the gas generator housing (1) and the gas generator inner cavity (2), and the annular gap is filled with heat insulation material or arranged with cooling channels.

5. The outward-expanding wingtip jet gas generator without compressed air inlet according to claim 1, characterized in that, The propellant delivery pipe (3) is equipped with a flow control valve, and the propellant is high-concentration hydrogen peroxide or a propellant mixture with high-concentration hydrogen peroxide as the main component.

6. The outward-expanding wingtip jet gas generator without compressed air inlet according to claim 1, characterized in that, The ratio of the cross-sectional area of ​​the gas outlet (5) to the cross-sectional area of ​​the bottom end of the gas generator housing (1) is 1.5 to 3.5:

1.

7. The outward-expanding wingtip jet gas generator without compressed air inlet according to claim 1, characterized in that, The ratio of the outlet diameter of the gas generator inner cavity (2) to the top outlet diameter of the gas generator housing (1) is 0.55 to 0.70:

1.

8. The outward-expanding wingtip jet gas generator without compressed air inlet according to claim 7, characterized in that, The ratio of the outlet diameter of the gas generator inner cavity (2) to the top outlet diameter of the gas generator housing (1) is 0.60 to 0.65:1.

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