tubular diffuser and hydrogen fuel turbine engine

Abstract

This invention relates to the field of compressor technology, providing a tubular diffuser and a hydrogen fuel turbine engine. The tubular diffuser includes: a tubular body with an internal airflow channel; the tubular body includes a first section and a second section connected together, the end of the first section facing away from the second section being the inlet, and the end of the second section facing away from the first section being the outlet; an arc-shaped bend section connecting the first and second sections; and a flow guide element disposed on the inner side of the second section near the outlet end, the extension direction of the flow guide element being the same as the airflow direction. In the tubular diffuser and hydrogen fuel turbine engine provided by this invention, when the airflow passes through the end section of the airflow channel, the presence of the flow guide element constrains and accelerates the low-energy fluid that might otherwise separate, suppressing the formation of large-scale vortices in the outlet region. Simultaneously, the guiding effect of the flow guide element on the mainstream makes the airflow angle at various circumferential positions tend to be consistent, significantly improving the circumferential uniformity of the outlet airflow.

Description

Technical Field

[0001] This invention relates to the field of compressor technology, and more particularly to a tubular diffuser and a hydrogen fuel turbine engine. Background Technology

[0002] Centrifugal compressors are widely used in aero engines, ground gas turbines, and industrial process equipment due to their compact structure, high pressure ratio, and high reliability. In a centrifugal compressor, the diffuser effectively converts the kinetic energy of the gas flowing out of the impeller at high speed into pressure energy, making it a key component affecting the overall performance of the compressor. Tubular diffusers, a special type of bladed diffuser, consist of a series of circumferentially distributed tubular channels. They are particularly suitable for centrifugal compressors with high pressure ratios because they can better adapt to the complex flow at the impeller outlet, effectively control the airflow direction, reduce friction losses, and maintain high efficiency over a wide flow range. Furthermore, hydrogen fuel combustion chambers have a significant risk of hydrogen combustion oscillation or detonation; the high-velocity throat of the tubular diffuser can prevent or reduce the propagation of pressure oscillations upstream to the compressor.

[0003] However, influenced by complex factors such as the unique "wake-jet" phenomenon at the centrifugal impeller outlet, drastic changes in flow channel curvature, and tip leakage flow, the impeller outlet airflow exhibits significant non-uniformity and unsteadiness. This deteriorates the inlet conditions of the downstream diffuser. Although tubular diffusers, with their large forward-swept leading edge and naturally formed three-dimensional curved structure, improve their adaptability to distorted inlet airflow to some extent, severe airflow problems still generally exist in their outlet region. Studies have shown that the axial outlet airflow of tubular diffusers is characterized by extreme circumferential non-uniformity. This non-uniformity is mainly manifested in significant differences in airflow velocity, pressure, and airflow angle in the circumferential direction, inducing large-scale eddies and energy losses in the region near the diffuser outlet. These flow distortions and losses in the outlet region not only reduce the total pressure recovery coefficient of the diffuser itself but also severely deteriorate the inlet conditions of downstream components (such as the recirculator or combustion chamber). For centrifugal compressors using tubular diffusers, the decline in the quality of their outlet airflow will have a series of adverse effects.

[0004] First, the strong eddies and flow separation in the outlet region are the main causes of energy loss, directly leading to a reduction in compressor efficiency. Second, this circumferentially non-uniform outlet flow field directly affects the performance and matching of downstream components. When the airflow enters the combustion chamber, the velocity distortion and pressure pulsation at the diffuser outlet are transmitted to the combustion chamber inlet, resulting in poor flow field uniformity at the combustion chamber inlet and the existence of a large area of ​​flow distortion. This will directly affect the flame stability, mixing effect, and outlet temperature field quality of the combustion chamber, and may even induce oscillating combustion, endangering the structural integrity and operational reliability of the combustion chamber and engine.

[0005] Therefore, improving the flow characteristics of the airflow at the outlet of the tubular diffuser and solving the problems of severe airflow distortion and large flow loss in the outlet region of the tubular diffuser are crucial to improving the overall performance and the working stability of the combustion chamber. Summary of the Invention

[0006] This invention provides a tubular diffuser to address the shortcomings of severe airflow distortion and large flow losses in the outlet region of existing tubular diffusers. It enables active intervention in the boundary layer flow and mainstream direction before the outlet, suppressing the generation and development of eddies in the outlet region, improving the velocity uniformity and angular distribution of the airflow, thereby ensuring that the airflow exiting the diffuser has better flow quality.

[0007] This invention provides a tubular diffuser, comprising: The tubular body has an internal airflow channel; the tubular body includes a first section and a second section connected together, the end of the first section facing away from the second section is the inlet, and the end of the second section facing away from the first section is the outlet; An arc-shaped bend connects the first section and the second section; a flow guide element is provided on the inner side of the second section near the outlet end, and the extension direction of the flow guide element is the same as the airflow direction.

[0008] According to a tubular diffuser provided by the present invention, the flow guiding element includes one or more, and the end of the flow guiding element facing away from the outlet is configured as arc-shaped.

[0009] According to a tubular diffuser provided by the present invention, the flow guiding element includes a closed flow guiding structure, the two sides of the closed flow guiding structure being connected to the inner sidewalls of the second section respectively, the closed flow guiding structure dividing the airflow channel into a plurality of first sub-channels, the plurality of first sub-channels being isolated from each other.

[0010] According to a tubular diffuser provided by the present invention, the flow guiding element includes an open flow guiding structure, one side of the open flow guiding structure is connected to the inner wall of the second section, and the other side is spaced apart from the inner wall of the second section. The open flow guiding structure divides the airflow channel into a plurality of second sub-channels, and the plurality of second sub-channels are partially connected.

[0011] According to a tubular diffuser provided by the present invention, the first section is a gradually expanding horn-shaped structure, and the cross-sectional dimensions of the first section gradually expand from small to large along its axial direction; the arc-shaped bend section is used to achieve airflow deflection; the longitudinal section of the second section is flat.

[0012] According to a tubular diffuser provided by the present invention, the surface of the flow guiding element is provided with fins or eddy current generators.

[0013] According to the present invention, a tubular diffuser is provided in which the first section, the arc bend section and the second section are integrally formed.

[0014] According to a tubular diffuser provided by the present invention, the shortest distance between the two opposing side walls of the second section is h, and the extension length of the flow guiding element is a, wherein the value of a ranges from h to 8h.

[0015] According to a tubular diffuser provided by the present invention, the tail end of the flow guiding element is flush with the outlet of the second section.

[0016] The tubular diffuser provided by this invention has an airflow channel within a tubular body. The tubular body includes a first section and a second section connected together. The end of the first section facing away from the second section is the inlet, and the end of the second section facing away from the first section is the outlet. An arc-shaped bend connects the first and second sections. A flow guide element is provided on the inner side of the second section near the outlet end. The extension direction of the flow guide element is the same as the airflow direction. The incoming airflow is compressed by a centrifugal impeller and enters the tubular diffuser, where the kinetic energy is converted into pressure energy within the diffuser channel. When the airflow passes through the end section of the diffuser channel, the flow guide element begins to function, forming a convergent-expanding channel between the flow guide element and the inner wall of the tubular body. When the airflow passes through this region, the presence of the flow guide element constrains and accelerates the low-energy fluid that might otherwise separate, suppressing the formation of large-scale vortices in the outlet region. At the same time, the guiding effect of the flow guide element on the mainstream makes the airflow angle at various circumferential positions tend to be consistent, significantly improving the circumferential uniformity of the outlet airflow.

[0017] The present invention also provides a hydrogen fuel turbine engine that, due to including the tubular diffuser as described above, possesses the various advantages described above. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0019] Figure 1 This is one of the structural schematic diagrams of the tubular diffuser provided by the present invention.

[0020] Figure 2 This is the second schematic diagram of the tubular diffuser provided by the present invention.

[0021] Figure 3 This is the third schematic diagram of the tubular diffuser provided by the present invention.

[0022] Figure 4This is the fourth schematic diagram of the tubular diffuser provided by the present invention.

[0023] Figure 5 This is a line graph showing the simulation results of the outlet airflow velocity and the ratio of the angle between the axis and the outlet area for the prototype diffuser and the diffuser with added guide elements.

[0024] Figure 6 This is a schematic diagram of the structure of the hydrogen fuel turbine engine provided by the present invention.

[0025] Figure label: 10. Tubular body; 11. First section; 12. Circular arc bend section; 13. Second section; 20. Flow guide element; 30. Compressor; 40. Gas turbine; 41. Combustion chamber; 50. Power turbine. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0027] The following is combined Figures 1 to 4 The present invention describes a tubular diffuser that decelerates and diffuses the high-speed airflow from the compressor stage during the operation of a hydrogen fuel turbine engine, thereby increasing the airflow pressure to meet the requirements of subsequent combustion and power operations of the engine. It adapts to the special requirements of hydrogen fuel combustion characteristics on airflow parameters and solves the problems of poor airflow stability, low diffusion efficiency, and insufficient adaptability of traditional diffusers in hydrogen fuel turbine engines.

[0028] The tubular diffuser provided in this embodiment of the invention includes a tubular body 10, which has an airflow channel inside. The tubular body 10 provides a flow path for the high-speed airflow discharged from the hydrogen fuel turbine engine, avoids leakage during the airflow diffusion process, and ensures that all the airflow participates in the diffusion process.

[0029] The tubular body 10 includes a first section 11 and a second section 13 connected in sequence. The structural parameters of the first section 11 and the second section 13 can be set according to the flow velocity and pressure characteristics of the airflow after the compressor stage, so as to achieve staged diffusion and avoid the problems of excessive airflow impact and pressure loss caused by a single structure. The end of the first section 11 facing away from the second section 13 is the inlet, and the end of the second section 13 facing away from the first section 11 is the outlet, ensuring that the airflow can flow from the first section 11 to the second section 13 and that the airflow can flow through the diffuser according to the preset path. This adapts to the overall airflow circulation system of the hydrogen fuel turbine engine and ensures smooth engine intake and exhaust.

[0030] The arc bend section 12 connects the first section 11 and the second section 13. The inner side of the second section 13 near the outlet end is provided with a flow guide element 20. The extension direction of the flow guide element 20 is the same as the airflow direction, which can reduce the local resistance and eddies of the airflow during the turning process, avoid pressure loss caused by sudden changes in flow velocity when the airflow turns, and prevent airflow turbulence caused by eddies, thus ensuring the continuity of airflow. The extension direction of the flow guide element 20 is the same as the airflow direction, which can guide the airflow near the outlet.

[0031] The working principle of the tubular diffuser provided in this embodiment of the invention is as follows: incoming air is compressed by a centrifugal impeller and enters the tubular diffuser, where kinetic energy is converted into pressure energy within the airflow channel. When the airflow passes through the end of the airflow channel, the guide element 20 begins to function, forming a convergent-expanding channel between the guide element 20 and the inner wall of the tubular body 10. As the airflow passes through this region, the presence of the guide element 20 constrains and accelerates the low-energy fluid that might otherwise separate, suppressing the formation of large-scale vortices in the outlet region. Simultaneously, the guiding effect of the guide element 20 on the mainstream makes the airflow angle at various circumferential positions more consistent, improving the circumferential uniformity of the outlet airflow.

[0032] In some feasible embodiments of the present invention, the flow guiding element 20 includes one or more, and the end of the flow guiding element 20 facing away from the outlet is configured as an arc. When one flow guiding element 20 is provided, the airflow at the outlet can be guided as a whole, which is simple in structure, easy to process and assemble, reduces the manufacturing cost of the diffuser, and at the same time reduces the obstruction to the airflow and reduces additional pressure loss.

[0033] When multiple flow guiding elements 20 are provided, the airflow at the outlet can be divided into multiple streams for separate guidance and sorting, further improving the uniformity of the airflow and adapting to the airflow flow requirements of the hydrogen fuel turbine engine under different operating conditions. When the airflow flow is large, multiple flow guiding elements can avoid the problem of insufficient guiding capacity of a single flow guiding element. The end of the flow guiding element 20 facing away from the outlet is set as an arc shape, which can avoid the airflow impact at the end of the flow guiding element 20, reduce airflow separation, and reduce local pressure loss. At the same time, the arc-shaped structure can guide the airflow to smoothly transition to the guiding surface of the flow guiding element 20, ensuring that the airflow flows smoothly along the extension direction of the flow guiding element 20, further improving the diffusion efficiency, while avoiding vortices generated at the sharp end, thereby reducing the impact on hydrogen fuel combustion in the downstream combustion chamber and reducing safety risks.

[0034] In some feasible embodiments of the present invention, the flow guiding element 20 includes a closed flow guiding structure, and the airflow channel is divided into multiple first sub-channels, which are isolated from each other. The two sides of the closed flow guiding structure are connected to the inner sidewall of the second section 13, which can enhance the structural stability of the flow guiding element 20, prevent deformation and shaking when the high-speed hydrogen fuel gas flow impacts the flow guiding element 20, and ensure that the flow guiding element 20 works reliably for a long time. The closed flow guiding structure divides the airflow channel into multiple isolated first sub-channels, which can realize the branching and guiding of the airflow, so that each airflow can be uniformly guided and diffused, avoid mutual interference between airflows in different areas, reduce eddies and backflow phenomena, and improve the uniformity and efficiency of diffusion. At the same time, the isolated first sub-channels can prevent the development and deterioration of complex flows such as internal vortices and backflows, and adapt to the requirements of hydrogen fuel combustion for airflow pressure and velocity, providing stable airflow parameters for the subsequent combustion process.

[0035] More specifically, in the above embodiments, the total length of the flow guiding element 20 is approximately 25-35 cm, and its thickness is 0.8 cm. The width of the flow guiding element is consistent with the width of the diffuser outlet wall.

[0036] In some feasible embodiments of the present invention, the flow guiding element 20 includes an open flow guiding structure. One side of the open flow guiding structure is connected to the inner wall of the second section 13, and the other side is spaced apart from the inner wall of the second section 13. Compared with a closed structure, the open flow guiding structure is easier to manufacture and can reduce obstruction to airflow and reduce pressure loss. The open flow guiding structure divides the airflow channel into multiple second sub-channels, which are partially connected. This not only allows for the initial guidance and sorting of the airflow through the flow guiding structure, but also enables the airflow in each sub-channel to compensate for each other, balance the pressure and velocity in each area, avoid excessively high or low local pressure, and ensure the uniformity of airflow at the outlet. At the same time, the partially connected structure facilitates the flow distribution of airflow when operating conditions change (such as engine load adjustment), improves the adaptability of the diffuser, meets the operating requirements of the hydrogen fuel turbine engine under different operating conditions, and ensures the stability of engine operation.

[0037] In the above embodiments, when the flow guiding element is an open flow guiding structure, the width of the flow guiding element is half the width of the flare. The head of the flow guiding element is rounded to 0.8 cm.

[0038] In some feasible embodiments of the present invention, the first segment 11 is a gradually expanding flared structure, with the cross-sectional dimensions of the first segment 11 gradually increasing from small to large along its axial direction. The gradually expanding flared structure enables the high-speed airflow entering the diffuser to gradually decelerate and diffuse, avoiding impacts and eddies caused by abrupt changes in the cross-section, reducing pressure loss, and gradually increasing the airflow pressure, laying the foundation for further diffusion in the second segment 13. The inlet cross-sectional dimension of the flared structure is relatively small, which can adapt to the airflow size at the outlet of the hydrogen fuel turbine engine, ensuring smooth airflow entry. The outlet cross-sectional dimension is enlarged to achieve initial diffusion, adapting to the requirement of airflow conversion from high speed and low pressure to low speed and high pressure, and improving diffusion efficiency.

[0039] The arc-shaped bend section 12 is used to achieve airflow deflection. In the overall structural layout of a hydrogen fuel cell turbine engine, the exhaust direction of the airflow often deviates from the intake direction of subsequent components at an angle. The arc-shaped bend section 12 can achieve smooth airflow deflection, avoiding airflow impact and pressure loss caused by right-angle deflection, ensuring the stability of airflow velocity and pressure during deflection, while reducing vortex generation, preventing airflow accumulation at the deflection point, and reducing safety hazards.

[0040] The longitudinal section of the second segment 13 is flat. The flat longitudinal section can increase the cross-sectional area of ​​the airflow, further improving the diffusion effect. At the same time, the flat structure can be adapted to the air intake shape of the downstream components (such as the combustion chamber) of the hydrogen fuel turbine engine, which facilitates the smooth entry of airflow into the downstream components and reduces airflow leakage and pressure loss at the interface. In addition, the flat structure can reduce the overall height of the diffuser, save internal installation space in the engine, adapt to the compact layout requirements of the hydrogen fuel turbine engine, and facilitate the installation and arrangement of the flow guiding element 20, thereby improving the flow guiding effect.

[0041] In some feasible embodiments of the present invention, the surface of the flow guiding element 20 is provided with ribs or vortex generators. The ribs can increase the contact area between the flow guiding element 20 and the airflow, while enhancing the structural strength of the flow guiding element 20 and preventing deformation caused by high-speed airflow impact. In addition, the ribs can further streamline the airflow, refine the airflow field, reduce local vortices, and improve the uniformity of the airflow.

[0042] The vortex generator can generate tiny vortices on the surface of the guide element 20, which disrupts the airflow boundary layer, reduces airflow separation, lowers pressure loss, and improves the mixing effect of the airflow. This makes the hydrogen fuel airflow mix more evenly with the air, providing better airflow conditions for the subsequent combustion process, improving the combustion efficiency of the engine, and adapting to the combustion characteristics of hydrogen fuel.

[0043] The flow guiding element 20 can be installed in a detachable structure, which makes it easy to replace the flow guiding element with different profile parameters according to different working conditions, so as to realize flexible control of the flow field at the outlet of the tubular diffuser.

[0044] In some feasible embodiments of the present invention, the first segment 11, the arc-shaped bend segment 12, and the second segment 13 are integrally formed. The integrally formed structure eliminates the connection interfaces between segments, avoiding leakage problems at the interfaces, ensuring the airflow channel's sealing, preventing airflow leakage, and reducing safety hazards. Simultaneously, the integral forming enhances the overall structural strength and rigidity of the tubular body 10, preventing loosening and deformation of the connection parts under high-speed airflow impact, ensuring long-term stable operation of the diffuser. Furthermore, the integral forming reduces assembly processes, lowers manufacturing costs and assembly errors, ensures the coaxiality and dimensional accuracy of each segment structure, and avoids problems such as airflow deviation and excessive pressure loss caused by assembly deviations, thus meeting the high precision and high sealing requirements of hydrogen fuel cell turbine engines for diffusers.

[0045] In some other embodiments, the first segment 11 and the arc-shaped bend segment 12 can also be connected in other ways, such as by a threaded connection. The arc-shaped bend segment 12 and the second segment 13 can be connected as a single piece.

[0046] In some feasible embodiments of the present invention, the shortest distance between the two opposing side walls of the second segment 13 is h, and the extension length of the flow guiding element 20 is a, where a ranges from h to 8h. Limiting the extension length a of the flow guiding element 20 to between h and 8h ensures that the flow guiding element 20 has sufficient guiding length to effectively guide the airflow, avoiding insufficient guiding effect due to an excessively short extension length, resulting in turbulent or deflected airflow. Simultaneously, it avoids excessively long extension lengths that would cause the flow guiding element 20 to obstruct the airflow excessively, significantly increasing pressure loss and affecting diffusion efficiency. This limitation of size range balances the guiding effect and pressure loss, adapts to the flat structure of the second segment 13, ensures that the flow guiding element 20 can fully exert its guiding function, and simultaneously considers diffusion efficiency, meeting the airflow parameter requirements of the hydrogen fuel cell turbine engine and ensuring the stability and economy of engine operation.

[0047] In some feasible embodiments of the present invention, the tail end of the guide element 20 is flush with the outlet of the second section 13, which can prevent the tail end of the guide element 20 from protruding beyond the outlet, prevent the protruding part from obstructing the exhaust airflow, reduce pressure loss, and prevent airflow backflow caused by the protruding tail end; it can also prevent the tail end of the guide element 20 from retracting into the inlet and outlet, preventing the retracted part from forming a vortex zone, causing airflow turbulence and affecting the uniformity of the outlet airflow. This configuration can ensure that the airflow, after being guided by the guide element 20, is smoothly and evenly discharged from the outlet and enters the subsequent components, adapting to the airflow requirements of the hydrogen fuel turbine engine's subsequent combustion, power, and other operating conditions, and improving the overall operating efficiency of the engine.

[0048] like Figure 5The diagram shown is a comparison of simulation results between the tubular diffuser in this embodiment of the invention and that in the prior art. It can be seen that placing the flow guiding element before the diffuser outlet actively intervenes in the airflow at the end of the diffuser, suppressing the generation and development of vortices in the outlet region, thus improving the quality of the outlet flow field from the source. The structure is simple and easy to implement. Only the flow guiding element needs to be added to the existing diffuser; there is no need to change the main structure of the diffuser, resulting in low manufacturing costs and facilitating engineering promotion.

[0049] Please see Figure 6 As shown, a second aspect of the present invention provides a hydrogen fuel turbine engine, including a compressor 30, a tubular diffuser, a gas turbine 40, and a power turbine 50. The tubular diffuser is disposed at the outlet of the compressor 30; the gas turbine 40 is disposed downstream of the tubular diffuser, and the outlet of the tubular diffuser is connected to the combustion chamber 41 of the gas turbine 40; the power turbine 50 is disposed downstream of the gas turbine 40.

[0050] In this embodiment, outside air is compressed by the compressor and then enters the combustion chamber 41 through the tubular diffuser to mix and burn with hydrogen fuel, producing high-temperature and high-pressure gas. The gas first drives the gas turbine 40 to rotate to drive the compressor 30 to maintain the working cycle, and then flows into the power turbine 50 to expand and do work. The power turbine 50 outputs mechanical work to the outside, realizing the conversion of the chemical energy of hydrogen fuel into shaft power output.

[0051] By adopting the aforementioned tubular diffuser, problems such as poor diffuser adaptability, insufficient airflow stability, and low diffusion efficiency in traditional centrifugal compressors can be solved. It adapts to the characteristics of hydrogen fuel gas flow, ensuring uniform gas pressure and stable flow velocity output from the centrifugal compressor. This provides stable gas flow conditions for the combustion process of the hydrogen fuel turbine engine, improves the working efficiency and reliability of the centrifugal compressor, and thus enhances the power performance, economy, and safety of the entire hydrogen fuel turbine engine, meeting the usage requirements of the hydrogen fuel turbine engine.

[0052] In the description of the embodiments of the present invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of the present invention according to the specific circumstances.

[0053] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "method," "specific method," or "some methods," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or method is included in at least one embodiment or method of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or method. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or methods. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or methods described in this specification, as well as the features of different embodiments or methods.

[0054] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A tubular diffuser, characterized in that, include: The tubular body (10) has an airflow channel inside; the tubular body (10) includes a first section (11) and a second section (13) connected together, the end of the first section (11) facing away from the second section (13) is the inlet, and the end of the second section (13) facing away from the first section (11) is the outlet; A circular arc bend (12) connects the first section (11) and the second section (13); a flow guide element (20) is provided on the inner side of the second section (13) near the outlet end, and the extension direction of the flow guide element (20) is the same as the airflow direction.

2. The tubular diffuser according to claim 1, characterized in that, The flow guiding element (20) includes one or more, and the end of the flow guiding element (20) facing away from the outlet is configured as arc-shaped.

3. The tubular diffuser according to claim 2, characterized in that, The flow guiding element (20) includes a closed flow guiding structure. The two sides of the closed flow guiding structure are respectively connected to the inner sidewalls opposite to the second section (13). The closed flow guiding structure divides the airflow channel into multiple first sub-channels, and the multiple first sub-channels are isolated from each other.

4. The tubular diffuser according to claim 2, characterized in that, The flow guiding element (20) includes an open flow guiding structure. One side of the open flow guiding structure is connected to the inner wall of the second segment (13), and the other side is spaced apart from the inner wall of the second segment (13). The open flow guiding structure divides the airflow channel into multiple second sub-channels, and the multiple second sub-channels are partially connected.

5. The tubular diffuser according to claim 3 or 4, characterized in that, The first segment (11) is a gradually expanding horn-shaped structure, and the cross-sectional dimensions of the first segment (11) gradually expand from small to large along its axial direction; the arc bend segment (12) is used to realize the airflow direction; the longitudinal section of the second segment (13) is flat.

6. The tubular diffuser according to claim 1, characterized in that, The surface of the flow guiding element (20) is provided with ribs or eddy current generators.

7. The tubular diffuser according to claim 1, characterized in that, The first segment (11), the arc bend segment (12), and the second segment (13) are integrally formed.

8. The tubular diffuser according to claim 1, characterized in that, The shortest distance between the two opposite side walls of the second segment (13) is h, and the extension length of the flow guiding element (20) is a, with the value of a ranging from h to 8h.

9. The tubular diffuser according to claim 1, characterized in that, The tail end of the flow guiding element (20) is flush with the outlet of the second section (13).

10. A hydrogen fuel cell turbine engine, characterized in that, include: Compressor (30); The tubular diffuser as described in any one of claims 1-9 is disposed at the outlet of the compressor (30); A gas turbine (40) is located downstream of the tubular diffuser, and the outlet of the tubular diffuser is connected to the combustion chamber (41) of the gas turbine (40). A power turbine (50) is located downstream of the gas turbine (40).

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