Vaneless diffuser adaptive to ultra-low specific speed sparse channel centrifugal hydrogen compressor

Abstract

According to the vaneless diffuser adaptive to the ultra-low-specific-speed sparse-channel centrifugal hydrogen compressor, the vaneless diffuser which is designed by combining an equal-thickness section and an expansion section is adopted, the equal-thickness section is a constant-diameter channel closely connected with an outlet of an impeller, a non-uniform flow field can be stabilized, and buffering transition can be achieved so that the airflow separation risk can be reduced; the expansion section is of a linear or slowly-changing angle conical structure, the outer diameter is expanded in the airflow direction, the expansion angle is controlled to be 2-8 degrees, and efficient conversion from dynamic pressure to static pressure is achieved through CFD optimization. The centrifugal hydrogen compressor is composed of the diffuser and a closed impeller, the impeller is in bolted connection with a wheel cover through a hub, the hub is provided with a shaft hole, a pull rod hole and a fairing, and the wheel cover is provided with reinforcing ribs. The structure is matched with a double-channel impeller and other multi-channel impellers, the problem that the efficiency and the pressure ratio of a traditional diffuser are limited is solved, the structure is suitable for hydrogen energy key links such as a hydrogen refueling station, and the system performance and stability are improved.

Description

Technical Field

[0001] This invention relates to the field of centrifugal compressor technology, and in particular to a bladeless diffuser adapted to a sparse-channel centrifugal hydrogen compressor with extremely low specific speed. Background Technology

[0002] With the rapid development of the hydrogen energy industry, hydrogen compression technology plays a core role in key aspects such as hydrogen refueling stations, hydrogen storage and transportation, and fuel cell gas supply. Centrifugal hydrogen compressors are widely used, especially in high-pressure hydrogen storage and high-purity hydrogen transmission, due to their continuous compression and oil-free characteristics. However, because hydrogen has extremely low density, small molecular weight, and strong diffusivity, and imposes hydrogen embrittlement requirements on structural materials, compression systems often operate under conditions characterized by high inlet total pressure, low mass flow rate, and low pressure ratio. These conditions directly result in extremely low design specific speeds for centrifugal compressors. Within this extremely low specific speed range, conventional centrifugal compressor structures face multiple technical bottlenecks to meet pressure ratio targets, particularly: insufficient impeller outlet channel height, high processing difficulty, low structural strength, and difficulty in kinetic energy recovery, ultimately limiting the overall pressure ratio and efficiency improvement.

[0003] To address this issue, the applicant proposed a design strategy of "increasing flow rate + reducing the number of channels" in a previous patent, constructing a dual-channel centrifugal impeller structure to improve the single-channel flow velocity and geometric height, alleviating the geometric constraints and aerodynamic coupling problems at low specific speeds. This structure has achieved breakthroughs in manufacturability and structural strength, but it also brings new challenges: the outlet flow of the dual-channel impeller is strongly asymmetrical and non-uniform, exhibiting flow characteristics such as the coexistence of high-speed and recirculation regions and significant trailing-edge vortices. If the diffuser structure is not compatible with these characteristics, it will lead to low kinetic energy recovery efficiency and limited static pressure increase, significantly restricting the overall system performance. Currently, typical diffuser structures are as follows: Uniform thickness bladeless diffuser: This structure is widely used in conventional high specific speed centrifugal compressors, relying on uniform and symmetrical incoming flow conditions to achieve dynamic pressure recovery. It has a simple structure and is easy to manufacture, but at extremely low specific speeds, the dynamic pressure itself is small, and the diffuser section has no effective area change, resulting in weak static pressure recovery capability and limited efficiency improvement. Radial contraction bladeless diffuser: Typically used in micro compressors or blowers, it achieves local kinetic energy compression through geometric contraction. However, under conditions such as high hydrogen pressure and low flow rate, due to the extremely low Reynolds number, the gas flow boundary layer is prone to premature separation, inducing instability and backflow, limiting its stability and usable diffusion range. Diffuser with bladed guide structure: It has good aerodynamic performance and high pressure recovery capability, but its structure is complex, space requirements are large, and it is particularly sensitive to inflow non-uniformity, making it unsuitable for dual-channel strongly biased flow fields; it also increases the difficulty of manufacturing and assembly, making it difficult to implement in hydrogen compression environments with extremely small structural dimensions.

[0004] In summary, the two main technical problems in the impeller-diffuser coupled design of ultra-low specific speed hydrogen centrifugal compressors are: first, insufficient flow expansion at the impeller outlet in traditional structures, leading to low diffusion efficiency; and second, existing bladeless diffusers suffer from large flow losses and limited pressure ratio improvement in small-size structures. Existing diffuser structures fail to effectively adapt to the asymmetric, high-speed, and non-uniform flow characteristics unique to dual-channel structures, and have not undergone systematic matching optimization for the combined requirements of ultra-low specific speed, low flow rate, and high pressure conditions in hydrogen compressors. Therefore, there is an urgent need for a diffuser structure that balances structural simplicity, aerodynamic adaptability, and dynamic pressure recovery capability to effectively improve the overall performance of dual-channel compression systems. Summary of the Invention

[0005] The purpose of this invention is to provide a bladeless diffuser adapted to a sparse-channel centrifugal hydrogen compressor with extremely low specific speed. It adopts a combined design of "equal thickness section and expansion section", which can achieve efficient matching with the outlet flow field of the dual-channel centrifugal impeller in terms of both geometry and aerodynamic performance.

[0006] According to one objective of the present invention, a bladeless diffuser adapted to an extremely low specific speed sparse channel centrifugal hydrogen compressor is provided, comprising a hub-side portion and a rim-side portion. The rim-side portion includes a constant-thickness section and an expansion section, and the rim-side portion and the hub-side portion together form the diffuser outlet. The constant-thickness section is located immediately after the impeller outlet and is a constant-diameter channel with inner and outer diameters consistent with the impeller outlet. The outer diameter of the expansion section gradually increases along the airflow direction, and its geometry adopts a linear or gradually changing angle cone structure, with the expansion angle controlled between 2° and 8°.

[0007] Furthermore, the constant thickness section initially stabilizes and buffers the flow field, providing stable intake conditions for the expansion section by suppressing velocity gradients and pressure abrupt changes.

[0008] Furthermore, the expansion angle of the expansion segment is preferably 3°~6°, and the expansion angle and length parameters are systematically optimized through CFD numerical simulation.

[0009] Furthermore, the expansion segment is replaced by a parabolic gradually changing expansion segment, an exponential gradually changing expansion segment, or a multi-segment stepped expansion segment.

[0010] Furthermore, the direction change of the expansion segment is selected from any of the following: The expansion occurs only on the rim side, while the hub side remains constant. The rim side expands, while the hub side experiences gradual, slight expansion. The wheel rim expands symmetrically on both sides, but the expansion angles are not equal, with the rim side angle being much larger than the hub side angle. The wheel rim features a variable wall curvature design, with linear or exponentially widening rims and a constant diameter or slightly concave shape on the hub side.

[0011] Furthermore, the bladeless diffuser adopts a split structure, which facilitates connection with the volute or the flange of the subsequent compression unit.

[0012] Furthermore, the structure and parameter design of the bladeless diffuser are suitable for multi-channel impeller outlet flow fields such as dual-channel, three-channel, or four-channel diffusers, and the adaptation is achieved by corresponding matching in the diffuser inlet geometry.

[0013] According to another objective of the present invention, a centrifugal hydrogen compressor is provided, comprising an impeller portion and the aforementioned bladeless diffuser. The impeller portion is a closed impeller formed by bolting a hub and a cover. The hub is provided with a shaft hole, a tie rod hole, and a shroud. The hub is provided with an annular stop. The annular stop cooperates with the weight reduction structure on the cover to achieve torque transmission and center positioning. The airflow flows out through the impeller channel and then enters the bladeless diffuser.

[0014] Furthermore, the fairing is threaded onto the hub to cover the tie rod nut and achieve rectification.

[0015] Furthermore, the non-flow channel portion of the wheel cover is deweighted, while reinforcing ribs are retained to increase impeller rigidity.

[0016] This invention addresses the asymmetric flow at the impeller outlet under conditions of extremely low specific speed, small flow rate, and high-pressure hydrogen. Through a "constant thickness section + expansion section" design, the constant thickness section first stabilizes the flow field and buffers the transition, reducing the risk of separation. Then, the expansion section, with an optimized expansion angle (2°~8°), efficiently converts dynamic pressure into static pressure, improving pressure ratio and efficiency. The structure is bladeless, simplifying manufacturing and maintenance, and is compatible with multi-channel impellers. It solves the problems of low efficiency and limited pressure ratio of traditional diffusers under these conditions, enhancing the applicability and performance stability of centrifugal hydrogen compressors in key aspects of the hydrogen energy industry. Attached Figure Description

[0017] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0018] Figure 1 This is a partial structural schematic diagram of a hydrogen centrifugal compressor according to an embodiment of the present invention; Figure 2 This is another structural schematic diagram of the hydrogen centrifugal compressor according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the wheel cover structure according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the wheel hub structure according to an embodiment of the present invention; Figure 5 This is a comparison chart of the simulation efficiency of three bladeless diffuser structures according to embodiments of the present invention; Figure 6 This is a comparison chart of the simulated pressure ratios of three bladeless diffuser structures according to embodiments of the present invention.

[0019] In the diagram: 1. Flange side section; 2. Hub side section; 3. Hub; 4. Equal thickness section; 5. Expansion section; 6. Diffuser outlet; 7. Fairing; 8. Tie rod hole; 9. Shaft hole; 10. Impeller passage; 11. Reinforcing rib; 12. Bolt; 13. Annular stop; 14. Wheel cover. Detailed Implementation

[0020] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. 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.

[0021] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0022] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified. Furthermore, the terms "installed," "connected," and "linked" should be interpreted broadly; for example, they may refer to a fixed connection, a detachable connection, or an integral connection; they may refer to a mechanical connection or an electrical connection; they may refer to a direct connection or an indirect connection through an intermediate medium; and they may refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0023] Example 1 like Figures 1-4As shown, a bladeless diffuser adapted to an extremely low specific speed sparse channel centrifugal hydrogen compressor includes a hub-side portion 2 and a rim-side portion 1, wherein the rim-side portion 1 includes a uniform thickness section 4 and an expansion section 5, which together with the hub-side portion 2 form the diffuser outlet 6.

[0024] The first core design element of this embodiment is the "equal thickness channel section," specifically equal thickness section 4. Equal thickness section 4 is immediately adjacent to the impeller outlet and its main function is to provide initial stabilization and buffering of the flow field. Under extremely low specific speed conditions, the airflow outlet velocity distribution is significantly non-uniform. If the airflow directly enters the expansion section 5, it can easily lead to boundary layer disturbances and airflow separation, resulting in dynamic pressure loss and efficiency reduction. Therefore, this invention incorporates a constant diameter channel with inner and outer diameters matching the impeller outlet. By suppressing velocity gradients and pressure abrupt changes, it creates more stable intake conditions for the subsequent expansion section 5, effectively reducing separation risk and improving the overall steady-state performance of the diffuser.

[0025] The second structural innovation of this embodiment lies in the parameter optimization and design strategy of expansion section 5. The geometry of expansion section 5 adopts a linear or gradually changing angle cone structure, with its outer diameter gradually increasing along the airflow direction. The expansion angle is controlled between 2° and 8° to ensure optimal pressure recovery without inducing large-scale separation. This section's structure underwent systematic optimization of the expansion angle and length parameters through CFD numerical simulation. While ensuring efficient conversion of dynamic pressure to static pressure, it effectively maintains the airflow's adherence to the wall, making it a key design element for achieving high pressure ratio and high efficiency.

[0026] This embodiment also provides a hydrogen centrifugal compressor, which mainly consists of an impeller section and the aforementioned bladeless diffuser, wherein: After the hub 3 and the cover 14 are machined separately, they are connected by bolts 12 to form a closed impeller. The hub 3 is provided with a shaft hole 9, a tie rod hole 8 and a rectifier 7 covering the tie rod nut, which are used to install the motor shaft, install the tie rod and rectify the flow, respectively. The rectifier 7 is connected to the hub by threads. The hub 3 is provided with an annular stop 13. The annular stop 13 on the hub 3 cooperates with the weight reduction structure on the cover 14 to realize the torque transmission and center positioning between the hub 3 and the cover 14.

[0027] The non-flow channel portion of the impeller cover 14 is appropriately weighted, and reinforcing ribs 11 are retained in appropriate positions to increase impeller rigidity; the airflow flows out through the impeller channel 10 and enters the bladeless diffuser.

[0028] Example 2 like Figures 1-4 As shown, a bladeless diffuser adapted to an extremely low specific speed sparse channel centrifugal hydrogen compressor includes a rim side portion 1 and a hub side portion 2. The rim side portion 1 includes a uniform thickness section 4 and an expansion section 5. The rim side portion 1 and the hub side portion 2 together form the diffuser outlet 6.

[0029] The equal thickness section 4 is located immediately after the impeller outlet of the centrifugal compressor. The equal thickness section 4 is a constant diameter channel with the same inner and outer diameters as the impeller outlet.

[0030] The outer diameter of expansion section 5 gradually increases along the airflow direction. Expansion section 5 adopts a linear geometry and a gradually changing angle cone structure. The expansion angle of expansion section 5 is controlled between 2° and 8°, preferably between 3° and 6°. The expansion angle and length parameters of expansion section 5 are systematically optimized through CFD numerical simulation.

[0031] In this embodiment, expansion segment 5 can be replaced by a parabolic, gradually varying expansion segment. The expansion segment can also be replaced by an exponentially varying expansion segment. Furthermore, expansion segment 5 can be replaced by a multi-segment stepped expansion segment.

[0032] The direction of expansion segment 5 changes in the following ways: expansion only on the rim side, while the rim side remains constant; or expansion on the rim side, while the rim side gradually expands slightly; or expansion 5 changes in the following ways: symmetrical expansion on both sides, but with unequal expansion angles, with the rim side angle being much larger than the rim side angle.

[0033] The expansion section 5 adopts a variable wall curvature design, with the rim side featuring linear or exponential gradual expansion, and the hub side having a constant diameter or slightly concave shape.

[0034] This bladeless diffuser has a split structure, which facilitates connection with the volute or the flange of the subsequent compression unit, making assembly and maintenance convenient.

[0035] An ultra-low specific speed hydrogen centrifugal compressor includes an impeller section and the aforementioned bladeless diffuser, wherein: The impeller part includes a hub 3 and a cover 14, which are connected by bolts 12 to form a closed impeller.

[0036] The hub 3 is provided with a shaft hole 9 for mounting the motor shaft.

[0037] The hub 3 is provided with a tie rod hole 8 for mounting a tie rod.

[0038] The hub 3 is equipped with a fairing 7 that covers the tie rod nut. The fairing 7 is used for rectification. The fairing 7 is connected to the hub by threads. The hub 3 is provided with an annular stop 13. The annular stop 13 on the hub 3 cooperates with the weight reduction structure on the wheel cover 14 to realize the torque transmission and center positioning between the hub 3 and the wheel cover 14.

[0039] The non-flow channel portion of the impeller cover 14 is weight-reduced, and the reinforcing ribs 11 are retained on the impeller cover 14 to increase impeller rigidity.

[0040] Example 3 like Figures 1-4As shown, the present invention provides a bladeless diffuser adapted to an extremely low specific speed sparse channel centrifugal hydrogen compressor. The hydrogen centrifugal compressor is mainly composed of an impeller part and a bladeless diffuser part.

[0041] After the hub 3 and the cover 14 are processed separately, they are connected by bolts 12 to form a closed impeller. The hub is provided with a shaft hole 9, a tie rod hole 8 and a rectifier 7 covering the tie rod nut, which are used to install the motor shaft, install the tie rod and rectify the flow, respectively. The rectifier 7 is connected to the hub by threads. The hub 3 is provided with an annular stop 13. The annular stop 13 on the hub 3 cooperates with the weight reduction structure on the cover 14 to realize the torque transmission and center positioning between the hub 3 and the cover 14.

[0042] The non-flow channel portion of the impeller cover 14 is appropriately weighted, and reinforcing ribs 11 are retained in appropriate positions to increase impeller rigidity; the airflow flows out through the impeller channel 10 and enters the bladeless diffuser.

[0043] The bladeless diffuser section includes a hub-side section 2 and a rim-side section 1. The rim-side section 1 includes a constant-thickness section 4 and an expansion section 5, which together with the hub-side section 2 form the diffuser outlet 6.

[0044] The equal-thickness section 4 is immediately connected to the impeller outlet and is a constant-diameter channel with the same inner and outer diameters as the impeller outlet. This channel initially stabilizes and buffers the flow field, suppresses velocity gradients and pressure abrupt changes, and creates more stable intake conditions for the subsequent expansion section.

[0045] The geometry of expansion section 5 adopts a linear or gradually changing angle cone structure, with its outer diameter gradually increasing along the airflow direction. The expansion angle is controlled between 2° and 8°, preferably between 3° and 6°. The expansion angle and length parameters are systematically optimized through CFD numerical simulation to achieve efficient conversion of dynamic pressure to static pressure and maintain the airflow adhering to the wall.

[0046] like Figure 5 and Figure 6 As shown, through simulation data comparison, including three bladeless diffuser structures: equal thickness, direct expansion, and equal thickness, expansion composite diffuser, the results show that the equal thickness and expansion type have the best performance.

[0047] This structure, through a reasonable flow channel configuration and precise aerodynamic matching, adapts to and guides the complex flow at the outlet of the dual-channel centrifugal impeller, effectively improving the pressure ratio and dynamic pressure recovery efficiency. It is particularly suitable for compressor systems operating under complex conditions such as extremely low specific speed, small flow rate, and high-pressure hydrogen.

[0048] In the above embodiment, the current expansion section uses a linear gradual expansion form to achieve the conversion of dynamic pressure to static pressure, which can also be replaced by: Parabolic or exponential gradually varying expansion section: Compared with linear expansion, it is conducive to gradual changes in pressure gradient while maintaining wall-attached flow, reducing the risk of local separation, and is suitable for a wider velocity range; Multi-segment stepped expansion: By expanding the channel cross-section in segments, the length and expansion amount of each segment are optimized by CFD to achieve a near-continuous diffusion effect, taking into account both manufacturing simplification and flow control.

[0049] In the above embodiments, the direction of the expansion segment can also be changed in the following ways: (1) Only the rim side expands, while the hub side remains constant; (2) Flange side expansion, hub side gradual micro-expansion; (3) Symmetrical expansion on both sides, but the expansion angles are not equal, with the rim side angle being much larger than the hub side angle; (4) Variable wall curvature design, with linear or exponential gradual expansion on the rim side and constant diameter or slightly concave shape on the hub side.

[0050] In the above embodiments, a multi-channel adaptive design can be adopted. The diffuser structure and parameter design are not only applicable to the flow field at the outlet of the dual-channel impeller, but also to multi-channel structures such as three-channel and four-channel. As long as the diffuser inlet geometry is matched accordingly, it can be widely adapted to various small hydrogen centrifugal compressors, and has good versatility and expandability.

[0051] In summary, the structure of this invention fully considers the asymmetric flow characteristics at the impeller outlet under special operating conditions such as extremely low specific speed, small flow rate, and high hydrogen pressure. By setting a "constant thickness section" to pre-stabilize the impeller outlet flow field, it achieves flow buffering and uniform transition, providing better intake conditions for the diffuser section. This design can effectively suppress separation and backflow problems caused by biased flow, and is superior to the adaptability of constant thickness and blade guide structures under non-uniform inflow conditions.

[0052] Compared to the complex three-dimensional blade structure of bladed diffusers, this invention features a pure bladeless, axisymmetric annular channel, which can be manufactured through conventional CNC machining or 3D printing. Its compact structure makes it suitable for integration and installation in micro-compressor systems. Simulation data comparisons show that the composite diffuser with equal thickness and expansion outperforms the bladeless diffuser with equal thickness and direct expansion.

[0053] 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 or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A vaneless diffuser adapted to a very low specific speed sparse channel centrifugal hydrogen compressor, characterized in that, The hub side part and the rim side part are included, and the rim side part includes an equal thickness section and an expansion section, and the hub side part and the rim side part jointly form a diffuser outlet; the equal thickness section is arranged next to an impeller outlet, and is a constant diameter channel with an inner diameter and an outer diameter consistent with the impeller outlet; the outer diameter of the expansion section gradually expands along the airflow direction, and the geometric shape adopts a linear or a slowly changing angle cone structure, and the expansion angle is controlled between 2° and 8°.

2. The vaneless diffuser of a low specific speed sparse channel centrifugal hydrogen compressor adapted according to claim 1, characterized in that, The equal thickness section preliminarily stabilizes and buffers the flow field, and provides stable air inlet conditions for the expansion section by inhibiting the flow velocity gradient and the pressure jump.

3. The vaneless diffuser of an adapted very low specific speed sparse channel centrifugal hydrogen compressor of claim 1, characterized in that, The expansion angle of the expansion section is preferably 3° to 6°, and the expansion angle and length parameters are systematically optimized through CFD numerical simulation.

4. The vaneless diffuser of an adapted very low specific diameter sparse channel centrifugal hydrogen compressor of claim 1, characterized in that, The expansion section is replaced by a parabolic slowly changing expansion section, an exponential slowly changing expansion section or a multi-section stepped expansion section.

5. The vaneless diffuser of an adapted very low specific diameter sparse channel centrifugal hydrogen compressor of claim 1, characterized in that, The direction change mode of the expansion section is selected from any one of the following modes: Only the rim side expands, and the hub side is constant; The rim side expands, and the hub side slowly changes and slightly expands; Both sides symmetrically expand, but the expansion angles are not equal, and the angle of the rim side is much larger than that of the hub side; Variable wall curvature design, the rim side adopts linear or exponential gradual expansion, and the hub side is constant diameter or slightly concave.

6. The vaneless diffuser of an adapted very low specific diameter sparse channel centrifugal hydrogen compressor of claim 1, characterized in that, The vaneless diffuser adopts a split structure, which is convenient for flange connection with a volute or a rear stage compression unit.

7. The vaneless diffuser of an adapted very low specific diameter sparse channel centrifugal hydrogen compressor of claim 1, characterized in that, The structure and parameter design of the vaneless diffuser are suitable for double-channel, three-channel or four-channel impeller outlet flow fields, and the adaptation is realized by corresponding matching on the diffuser inlet geometry.

8. A centrifugal hydrogen compressor employing a vaneless diffuser of a centrifugal hydrogen compressor according to any one of claims 1 to 7, characterized in that The vaneless diffuser includes an impeller part and the vaneless diffuser, the impeller part is formed by a hub and a cover through bolt connection to form a closed impeller, the hub is provided with a shaft hole, a pull rod hole and a fairing, the hub is provided with an annular stop, and the annular stop and a weight reduction structure on the cover are matched to realize torque transmission and center positioning; after the airflow flows out through the impeller channel, the airflow enters the vaneless diffuser.

9. The centrifugal hydrogen press of claim 8, wherein, The fairing is connected to the hub through threads, and is used for covering the pull rod nut and realizing flow regulation.

10. The centrifugal hydrogen press of claim 8, wherein, The cover is subjected to weight reduction treatment on a non-flow channel part, and a reinforcing rib is reserved to increase the rigidity of the impeller.

Images