A runner for a gas dynamic wheel

Abstract

This invention relates to the field of pneumatic turbine technology, specifically to a runner for a pneumatic turbine, which solves the problem of low efficiency in existing pneumatic turbine runners. The runner includes a hub, an outer ring, and multiple airfoil blades. The airfoil blades are connected between the hub and the outer ring, forming a gradually expanding blade flow channel. The airfoil blades are three-dimensional twisted airfoils, with different relative thicknesses, relative cambers, and installation angles on their inner and outer sides. Sub-flow channels are formed between adjacent blades, with their cross-sectional area gradually decreasing from the inlet to the outlet. The airflow directions at both the inlet and outlet are configured to be parallel or substantially parallel to the runner axis. The runner can be used in multiple stages in series, with the blade parameters of each stage progressively optimized along the airflow direction. This invention optimizes the airflow organization throughout the entire flow channel through the synergistic design of the gradually expanding flow channel and the three-dimensional twisted blades, significantly improving energy conversion efficiency. It achieves an overall efficiency of up to 89.8% in a four-stage pneumatic turbine, and also exhibits strong structural versatility.

Description

Technical Field

[0001] This invention relates to the field of pneumatic turbine technology, specifically to a runner for a pneumatic turbine. Background Technology

[0002] In special working environments such as mines, especially underground coal mine roadways, there are problems with methane gas and water leakage, requiring continuous ventilation and drainage operations. Due to explosion-proof and safety requirements, electric motors are usually avoided in these environments, and compressed air is used as the power source instead. However, existing pneumatic equipment, such as diaphragm pumps, often suffers from low efficiency and high energy consumption.

[0003] As a device that converts compressed air energy into rotational mechanical energy, the core working component of a pneumatic turbine is the runner. The quality of the runner design directly determines the energy conversion efficiency, output power, and operational stability of the pneumatic turbine. Traditional runner designs may suffer from poor airflow organization, large energy losses, and low efficiency, making it difficult to meet the power requirements of efficient drainage and ventilation equipment in underground mines.

[0004] Therefore, developing a high-efficiency dedicated runner suitable for multi-stage pneumatic turbines is of great practical significance for improving the overall performance of pneumatic equipment and meeting the power requirements under special working conditions. Summary of the Invention

[0005] In view of the shortcomings of the existing technology, the purpose of this invention is to provide a runner for a pneumatic turbine.

[0006] The objective of this invention can be achieved through the following technical solution: A runner for a pneumatic turbine, comprising a runner hub, a runner outer ring, and a plurality of airfoil blades, wherein the airfoil blades are uniformly spaced between the runner hub and the runner outer ring along the circumferential direction, wherein a blade flow channel is formed between the outer circumferential surface of the runner hub and the inner circumferential surface of the runner outer ring, and the blade flow channel is a gradually expanding flow channel; the airfoil blades are three-dimensional twisted airfoil structures, the airfoil blades are located within the blade flow channels, and a sub-flow channel extending along the airflow direction is formed between two adjacent airfoil blades, wherein the airflow direction at the inlet of the sub-flow channel is configured to be close to the tangential direction of the runner, and the airflow direction at the outlet of the sub-flow channel is configured to be close to the axial direction of the runner. The airflow enters the inlet of the sub-flow channel in a near-tangential direction and then enters the next stage from the outlet of the sub-flow channel in a near-axial direction. The airfoil blades employ a three-dimensional twisted design with different aerodynamic parameters on the inner and outer sides. This design allows the airflow across the entire airfoil to impact the blades at the optimal angle, generating higher lift and lower drag, thus significantly improving efficiency. The airflow direction at the inlet of the sub-channel is configured to approximate the tangential direction of the runner, while the airflow direction at the outlet of the sub-channel is configured to approximate the axial direction of the runner. This perfectly matches the tangential outflow of the front stage seat ring nozzle channel and the axial inflow of the rear stage seat ring nozzle channel, achieving precise control and efficient connection of the airflow direction throughout the entire flow channel. This minimizes impact and vortex losses caused by abrupt changes in airflow direction. This results in an overall turbine efficiency of up to 89.8% across the entire flow channel.

[0007] Furthermore, the blade channel is a blade channel that gradually expands along the airflow direction, and its blade channel expansion ratio is 0.005 to 0.008.

[0008] Furthermore, the diffusion ratio of the blade flow channel is 0.006 to 0.007. Using a diffusion ratio of 0.006 to 0.007, preferably 0.0061, 0.0062, or 0.0063, in the blade flow channel facilitates smooth expansion and deceleration of the airflow within the flow channel, more effectively transferring the pressure and kinetic energy of the airflow to the airfoil blades and converting it into the rotational torque of the rotor.

[0009] Furthermore, the relative thickness of the outer side of the airfoil is 10%~12%, the relative camber of the outer side is 11%~13%, the inlet installation angle of the outer side is 55 degrees~65 degrees, and the outlet installation angle of the outer side is 10 degrees~12 degrees; the relative thickness of the inner side is 15%~17%, the relative camber of the inner side is 27%~29%, the inlet installation angle of the inner side is -60 degrees~-55 degrees, and the outlet installation angle of the inner side is 12 degrees~14 degrees. The relative thickness of the outer side is the ratio of the thickness of the outer side to the airfoil length (the straight-line distance between the inlet and outlet ends of the airfoil centerline); the relative camber of the outer side is the ratio of the maximum distance from the centerline of the outer side to the airfoil length (the straight-line distance between the inlet and outlet ends of the airfoil centerline) to the airfoil length; the inlet installation angle of the outer side is the angle between the fluid inflow direction on the outer side and the opposite direction of the circumferential velocity component on the outer side; the outlet installation angle of the outer side is the angle between the fluid outflow direction on the outer side and the opposite direction of the circumferential velocity component on the outer side; the same applies to the inner side. The airfoil blades have an elliptical leading edge and a circular trailing edge. Airflow enters from the leading edge and exits from the trailing edge. The inlet installation angle and relative camber of the inner and outer sides of the airfoil have different aerodynamic parameters. This design can better adapt to the changes in relative velocity and direction of airflow at different radii from the rotor hub to the outer ring of the rotor, allowing the airflow across the entire blade span to impact the blades at the optimal angle, generating higher work capacity and lower drag, thereby significantly improving efficiency.

[0010] Furthermore, it includes four turbines: a first-stage turbine, a second-stage turbine, a third-stage turbine, and a fourth-stage turbine, arranged sequentially along the airflow direction. The first-stage turbine includes a first-stage blade, the second-stage turbine includes a second-stage blade, the third-stage turbine includes a third-stage blade, and the fourth-stage turbine includes a fourth-stage blade. This design is not only applicable to four-stage turbines, but theoretically also applicable to other numbers of stages, such as two-stage, three-stage, or different specifications of pneumatic turbines.

[0011] Furthermore, the outer side of the first-stage blade has a relative thickness of 10.13%, a relative camber of 12.72%, an inlet installation angle of 61.39 degrees, an outlet installation angle of 11.47 degrees, and an elliptical outer leading edge with a major-to-minor axis ratio of 3:1 and a minor axis length of 5 mm. The outer trailing edge is a circle with a diameter of 2 mm. The inner side has a relative thickness of 16.83%, a relative camber of 28.39%, an inlet installation angle of -59.4 degrees, an outlet installation angle of 13.54 degrees, and an elliptical inner leading edge with a major-to-minor axis ratio of 3:1 and a minor axis length of 5 mm. The inner trailing edge is a circle with a diameter of 2 mm.

[0012] Furthermore, the outer side of the second-stage blade has a relative thickness of 11.00%, a relative camber of 12.95%, an inlet installation angle of 60.40 degrees, an outlet installation angle of 11.44 degrees, and an elliptical outer leading edge with a major-to-minor axis ratio of 3:1 and a minor axis length of 5 mm. The outer trailing edge is a circle with a diameter of 2 mm. The inner side has a relative thickness of 16.72%, a relative camber of 28.5%, an inlet installation angle of -58.36 degrees, an outlet installation angle of 13.58 degrees, and an elliptical inner leading edge with a major-to-minor axis ratio of 3:1 and a minor axis length of 5 mm. The inner trailing edge is a circle with a diameter of 2 mm.

[0013] Furthermore, the outer wing of the three-stage blade has a relative thickness of 11.26%, a relative camber of 12.79%, an inlet installation angle of 59.33 degrees, an outlet installation angle of 11.41 degrees, and an elliptical outer wing leading edge with a major-to-minor axis ratio of 3:1 and a minor axis length of 5 mm. The outer wing trailing edge is a circle with a diameter of 2 mm. The inner wing has a relative thickness of 16.65%, a relative camber of 28.74%, an inlet installation angle of -57.24 degrees, an outlet installation angle of 13.62 degrees, and an elliptical inner wing leading edge with a major-to-minor axis ratio of 3:1 and a minor axis length of 5 mm. The inner wing trailing edge is a circle with a diameter of 2 mm.

[0014] Furthermore, the outer wing of the fourth-stage blade has a relative thickness of 11.21%, a relative camber of 12.55%, an inlet installation angle of 58.16 degrees, an outlet installation angle of 11.37 degrees, and an elliptical outer wing leading edge with a major-to-minor axis ratio of 3:1 and a minor axis length of 5 mm. The outer wing trailing edge is a circle with a diameter of 2 mm. The inner wing has a relative thickness of 16.71%, a relative camber of 28.87%, an inlet installation angle of -56.02 degrees, an outlet installation angle of 13.67 degrees, and an elliptical inner wing leading edge with a major-to-minor axis ratio of 3:1 and a minor axis length of 5 mm. The inner wing trailing edge is a circle with a diameter of 2 mm.

[0015] Furthermore, a seat ring is provided upstream of each stage of the runner. The seat ring has a nozzle flow channel. Airfoil guide vanes are evenly spaced along the circumferential direction in the nozzle flow channel. The outer outlet installation angle of the airfoil guide vanes is 12 to 15 degrees, and the inner outlet installation angle of the airfoil guide vanes is 10 to 13 degrees.

[0016] Compared with existing technologies, the technical advantages of this invention are as follows: The core innovation of the turbine proposed in this invention lies in its independent and complete power-generating module, which directly determines the ultimate performance of the aerodynamic turbine through its optimized structural design. This turbine uniquely combines a gradually expanding blade channel with a three-dimensional twisted airfoil blade and defines the key aerodynamic geometry parameter range. This combined design enables a single-stage turbine to achieve effective airflow organization and efficient energy extraction. Based on the outstanding contribution of this independent component, when applied to a four-stage tandem high-efficiency full-flow-channel aerodynamic turbine system, the overall efficiency reaches an excellent level of 89.8%. This fully demonstrates that the design of this turbine is a fundamental component guarantee for achieving high system-level efficiency. This turbine is not only adaptable to the specific four-stage system but can also be flexibly applied to various aerodynamic turbines with different numbers of stages and different power requirements, significantly improving the versatility, portability, and industrialization value of this high-efficiency power-generating component, providing a core component foundation for building high-efficiency and high-reliability aerodynamic power systems. Attached Figure Description

[0017] Figure 1 This is a perspective view of the rotating wheel of the present invention.

[0018] Figure 2 This is a cross-sectional view of the rotor of the present invention.

[0019] Figure 3 This is a schematic diagram of the airfoil blades and airfoil guide vanes of the rotor of the present invention.

[0020] Figure 4 This is a perspective view of the inner side of the airfoil blade of the present invention and a schematic diagram of the inner side of the airfoil.

[0021] Figure 5 This is a perspective view of the outer side of the airfoil blade of the present invention and a schematic diagram of the outer side of the airfoil.

[0022] Figure 6 This is a schematic diagram of the pneumatic turbine of the present invention.

[0023] Figure number markings: 1. Runner hub; 2. Runner outer ring; 3. Airfoil blade; 4. Blade flow channel; 5. Pressure relief hole; 6. Mounting hole; 7. Flow limiting protrusion; 8. Sub-flow channel; 9. Main shaft; 10. Volute; 11. First-stage runner; 12. Second-stage runner; 13. Third-stage runner; 14. Fourth-stage runner; 15. Seat ring; 16. First-stage guide vane; 17. Second-stage guide vane; 18. Third-stage guide vane; 19. Fourth-stage guide vane. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and preferred embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0025] according to Figures 1 to 6 The image shows a runner for a pneumatic turbine. As the core power-generating component of the pneumatic turbine, the performance of this runner directly determines the energy conversion efficiency of the entire machine. The runner of this invention mainly includes a runner hub 1, a runner outer ring 2, and multiple three-dimensionally twisted airfoil blades 3.

[0026] Multiple airfoil blades 3 are evenly and spaced apart along the circumferential direction between the rotor hub 1 and the rotor outer ring 2. The outer circumferential surface of the rotor hub 1 and the inner circumferential surface of the rotor outer ring 2 together form an annular blade flow channel 4. A sub-flow channel 8 extending along the airflow direction is formed between two adjacent airfoil blades 3. The airflow direction at the inlet of the sub-flow channel 8 is configured to be close to the tangential direction of the rotor, and the airflow direction at the outlet of the sub-flow channel 8 is configured to be close to the axial direction of the rotor. In particular, the entire blade flow channel 4 is configured as a gradually expanding channel along the airflow direction, and its expansion ratio (the ratio of the thickness or equivalent diameter of the outlet to the inlet) is designed in an optimized range of 0.005 to 0.008, preferably 0.006 to 0.007, for example 0.0061, 0.0062, 0.0063, 0.0064 or 0.0065. This gradually expanding design allows the high-pressure airflow to expand and decelerate smoothly as it flows through the rotor, thereby more effectively converting pressure energy and kinetic energy into rotational torque acting on the airfoil blade 3, thus improving energy conversion efficiency.

[0027] The key to this invention lies in the fact that the airfoil blade 3 is a three-dimensional twisted airfoil structure, and its airfoil geometry parameters have been finely optimized. The relative thickness, relative camber, and installation angle of each airfoil blade 3 change continuously from the rotor hub 1 (inner side of the airfoil) to the rotor outer ring 2 (outer side of the airfoil) to adapt to the changes in the relative speed and direction of the airflow at different radii.

[0028] In a preferred parametric design scheme, the key aerodynamic parameters of the airfoil blade are limited to the following efficient range:

[0029] Outer side of the wing (near the outer ring of the rotor): relative thickness of the outer side of the wing is 10%~12%, relative curvature of the outer side of the wing is 11%~13%, inlet installation angle of the outer side of the wing is 55°~65°, and outlet installation angle of the outer side of the wing is 10°~12°.

[0030] Inner side of the wing (near the rotor hub): relative thickness of the inner side of the wing is 15%~17%, relative curvature of the inner side of the wing is 27%~29%, inlet installation angle of the inner side of the wing is -60°~-55°, and outlet installation angle of the inner side of the wing is 12°~14°.

[0031] The leading edge of the airfoil blade 3 is designed as an ellipse (e.g., with a major-to-minor axis ratio of 3:1) to reduce inflow impact losses, while the trailing edge is circular. This irregular, three-dimensionally twisted design ensures that the airflow impacts the blade at a near-optimal angle of attack across the entire blade span from the hub to the outer ring, maximizing the effective lift that drives the turbine's rotation while minimizing flow separation and drag losses. This allows the turbine of this invention to function as a high-performance, independent working module. In the individual sub-channels 8 formed by adjacent airfoil blades 3, the airflow is guided by the three-dimensionally twisted blades, generating complex but controlled three-dimensional motion. Nevertheless, since the central flow surface of the entire aero turbine is constructed as a cylindrical surface coaxial with the turbine axis, it defines the ideal average path of the airflow as it passes through the turbine. This design ensures that, despite local flow variations, the aforementioned parameter design constrains and guides the mainstream airflow direction in all sub-channels 8 axially, achieving flow coordination and unity. The cylindrical characteristics of the central flow surface provide a benchmark for axial flow within the sub-channel 8, enabling the airflow to pass smoothly and efficiently through the impeller, maximizing energy conversion efficiency, and minimizing losses caused by flow direction deviation or turbulence.

[0032] The turbine assembly in a four-stage high-efficiency aerodynamic turbine. To demonstrate the superior performance and versatility of this turbine, a specific four-stage high-efficiency full-flow-path aerodynamic turbine system is used as an example. In this system, four turbines of this invention are arranged in series along the airflow direction, referred to as the first-stage turbine 11, the second-stage turbine 12, the third-stage turbine 13, and the fourth-stage turbine 14, respectively. These four turbines share the same core structure, but to adapt to changes in airflow pressure at each stage, the geometric parameters of their airfoil blades have been fine-tuned and optimized. The specific preferred implementation parameters are as follows:

[0033] The airfoil blades of the first-stage rotor: The outer relative thickness of the first-stage blade is 10.13%, the outer relative camber is 12.72%, the outer inlet installation angle is 61.39 degrees, the outer outlet installation angle is 11.47 degrees, the outer leading edge is an ellipse with a major-to-minor axis ratio of 3:1 and a minor axis length of 5 mm, and the outer trailing edge is a circle with a diameter of 2 mm; The inner relative thickness is 16.83%, the inner relative camber is 28.39%, the inner inlet installation angle is -59.4 degrees, the inner outlet installation angle is 13.54 degrees, the inner leading edge is an ellipse with a major-to-minor axis ratio of 3:1 and a minor axis length of 5 mm, and the inner trailing edge is a circle with a diameter of 2 mm.

[0034] The airfoil blades of the second-stage rotor: The outer relative thickness of the second-stage blade is 11.00%, the outer relative camber is 12.95%, the outer inlet installation angle is 60.40 degrees, the outer outlet installation angle is 11.44 degrees, the outer leading edge is an ellipse with a major-to-minor axis ratio of 3:1 and a minor axis length of 5 mm, and the outer trailing edge is a circle with a diameter of 2 mm; The inner relative thickness is 16.72%, the inner relative camber is 28.5%, the inner inlet installation angle is -58.36 degrees, the inner outlet installation angle is 13.58 degrees, the inner leading edge is an ellipse with a major-to-minor axis ratio of 3:1 and a minor axis length of 5 mm, and the inner trailing edge is a circle with a diameter of 2 mm.

[0035] The airfoil blades of the three-stage rotor: The outer relative thickness of the third-stage blade is 11.26%, the outer relative camber is 12.79%, the outer inlet installation angle is 59.33 degrees, the outer outlet installation angle is 11.41 degrees, the outer leading edge is an ellipse with a major-to-minor axis ratio of 3:1 and a minor axis length of 5 mm, and the outer trailing edge is a circle with a diameter of 2 mm; The inner relative thickness is 16.65%, the inner relative camber is 28.74%, the inner inlet installation angle is -57.24 degrees, the inner outlet installation angle is 13.62 degrees, the inner leading edge is an ellipse with a major-to-minor axis ratio of 3:1 and a minor axis length of 5 mm, and the inner trailing edge is a circle with a diameter of 2 mm.

[0036] The airfoil blades of the four-stage rotor: The outer relative thickness of the fourth-stage blade is 11.21%, the outer relative camber is 12.55%, the outer inlet installation angle is 58.16 degrees, the outer outlet installation angle is 11.37 degrees, the outer leading edge is an ellipse with a major-to-minor axis ratio of 3:1 and a minor axis length of 5 mm, and the outer trailing edge is a circle with a diameter of 2 mm; The inner relative thickness is 16.71%, the inner relative camber is 28.87%, the inner inlet installation angle is -56.02 degrees, the inner outlet installation angle is 13.67 degrees, the inner leading edge is an ellipse with a major-to-minor axis ratio of 3:1 and a minor axis length of 5 mm, and the inner trailing edge is a circle with a diameter of 2 mm.

[0037] When the four turbine modules using the specific parameters described above are integrated with matching components such as the seat ring 15 and volute 10 into a four-stage pneumatic turbine, the overall efficiency reaches an excellent level of 89.8% in actual measurements. This result fully verifies the fundamental role of the turbine design of this invention in achieving ultimate energy conversion efficiency.

[0038] To accommodate the aforementioned first-stage rotor 11, second-stage rotor 12, third-stage rotor 13, and fourth-stage rotor 14, a seat ring 15 is provided upstream of each rotor stage. The seat ring 15 contains a nozzle channel, within which airfoil guide vanes are evenly spaced along the circumferential direction. The outer exit angle of the airfoil guide vanes is 12 to 15 degrees, and the inner exit angle is 10 to 13 degrees. The seat rings are designated as first-stage, second-stage, third-stage, and fourth-stage seat rings, each including a first-stage guide vane 16, a second-stage guide vane 17, a third-stage guide vane 18, and a fourth-stage guide vane 19, respectively.

[0039] The first-stage guide vane is a three-dimensional twisted airfoil structure. The outer relative thickness is 10.02%, the outer relative camber is 1.76%, the outer inlet installation angle is 21.95 degrees, and the outer outlet installation angle is 13.12 degrees. The outer leading edge is an ellipse with a major-to-minor axis ratio of 3:1 and a minor axis length of 6.16 mm, and the outer trailing edge is a circle with a diameter of 2 mm. The inner relative thickness is 10.09%, the inner relative camber is 2.09%, the inner inlet installation angle is 19.77 degrees, and the outlet installation angle is 11.62 degrees. The inner leading edge is an ellipse with a major-to-minor axis ratio of 3:1 and a minor axis length of 5.36 mm, and the inner trailing edge is a circle with a diameter of 2 mm.

[0040] The outer side of the second-stage guide vane has a relative thickness of 14.86%, a relative camber of 18.54%, an inlet installation angle of 90 degrees, and an outlet installation angle of 13.15 degrees. The leading edge of the outer side is an ellipse with a major-to-minor axis ratio of 3:1 and a minor axis length of 5.5 mm, while the trailing edge is a circle with a diameter of 2 mm. The inner side has a relative thickness of 12.47%, a relative camber of 20.02%, an inlet installation angle of 90 degrees, and an outlet installation angle of 11.59 degrees. The leading edge of the inner side is an ellipse with a major-to-minor axis ratio of 3:1 and a minor axis length of 5 mm, while the trailing edge is a circle with a diameter of 2 mm.

[0041] The outer side of the third-stage guide vane has a relative thickness of 12.94%, a relative camber of 18.00%, an inlet installation angle of 90 degrees, and an outlet installation angle of 13.15 degrees. The leading edge of the outer side is an ellipse with a major-to-minor axis ratio of 3:1 and a minor axis length of 5 mm, while the trailing edge is a circle with a diameter of 2 mm. The inner side has a relative thickness of 12.47%, a relative camber of 20.24%, an inlet installation angle of 90 degrees, and an outlet installation angle of 11.56 degrees. The leading edge of the inner side is an ellipse with a major-to-minor axis ratio of 3:1 and a minor axis length of 5 mm, while the trailing edge is a circle with a diameter of 2 mm.

[0042] The fourth-stage guide vane has a relative thickness of 12.95% on the outer side, a relative camber of 18.01%, an inlet installation angle of 90 degrees, an outlet installation angle of 13.18 degrees, and an elliptical outer leading edge with a major-to-minor axis ratio of 3:1 and a minor axis length of 5.5 mm. The outer trailing edge is a circle with a diameter of 2 mm. The inner side has a relative thickness of 12.46%, a relative camber of 20.23%, an inlet installation angle of 90 degrees, an outlet installation angle of 11.55 degrees, and an elliptical inner leading edge with a major-to-minor axis ratio of 3:1 and a minor axis length of 5 mm. The inner trailing edge is a circle with a diameter of 2 mm.

[0043] After being rectified within the volute, the compressed air flows axially out of the volute outlet channel. Subsequently, the airflow sequentially passes through a four-stage series of "seat ring-rotor" combinations: in each seat ring, the axially flowing airflow (equivalent to an inlet installation angle of 90 degrees) is accelerated and adjusted to a helical direction with an outlet installation angle of approximately 13 degrees by three-dimensionally twisted guide vanes, impacting the rotor at an optimal tangential angle. In the corresponding rotor, the airflow, with a larger inlet installation angle (e.g., 61.39 degrees for the outer inlet installation angle of the first-stage rotor / -59.4 degrees for the inner inlet installation angle), meets the airflow as it passes over the airfoil blades, converting its kinetic and pressure energy into mechanical energy, causing the rotor to rotate. The rotated airflow then flows out in a near-axial direction (approximately 11-14 degrees). After four stages of continuous expansion and work, the pressure and temperature of the airflow are significantly reduced, and it is finally discharged from the engine through the axial exhaust channel in a near-axial direction, thus efficiently converting the internal energy of the compressed air into rotational mechanical energy to drive the main shaft.

[0044] Multiple pressure relief holes 5 are provided axially on the rotor hub 1. These holes help balance the pressure inside the hub cavity when the rotor rotates at high speed, reducing harmful axial forces, thereby improving the service life of the main shaft 9 bearing and the operational stability of the entire rotor system. Symmetrically protruding flow-limiting protrusions 7 are also provided on the rotor hub 1, which cooperate with components such as the seat ring 15 and the volute 10 to form a flow-limiting channel. The flow-limiting protrusions 7 can be one, two, or three, or other irregular structures. In the center of the rotor hub 1, there is an axially penetrating mounting hole 6 for fixing the main shaft 9, with pressure relief holes evenly distributed axially around the mounting hole 6.

[0045] For an annular blade flow channel formed by the outer circumferential surface of the impeller hub and the inner circumferential surface of the impeller outer ring, its central flow surface is defined as the intermediate curved surface of the flow channel in the radial direction (from the hub to the outer ring). This curved surface is located at the center of the inner and outer walls of the flow channel and can be regarded as an ideal representation of the average flow path of the airflow.

[0046] In the optimized design of this invention, the central flow surface of the blade channel of a single impeller is constructed as a cylindrical surface. The axis of this cylindrical surface coincides with the rotation axis of the impeller (i.e., the main shaft axis). This design ensures that the mainstream flow direction remains consistent and stable axially as the airflow passes through the entire annular cross-section of the impeller, providing an ideal airflow organization basis for the core work process.

[0047] More importantly, the diameter of the central flow surface of the runner proposed in this invention is designed to precisely match the diameter of the central flow surface of the nozzle flow channel outlet of the adjacent first-stage seat ring and the nozzle flow channel inlet of the second-stage seat ring in the pneumatic turbine. In a high-efficiency full-flow-channel pneumatic turbine, "the central flow surfaces of the volute 10 outlet flow channel, the nozzle flow channel of the first-stage seat ring, the blade flow channel of the first-stage runner, the nozzle flow channel of the second-stage seat ring, etc., are located on a cylindrical surface of the same diameter."

[0048] Therefore, the contribution of this invention's turbine runner lies in its function as an independent, modular power-generating component. Its cylindrical central flow surface with a specific diameter is a key element in achieving the "unified flow surface" design principle across the entire flow channel. By precisely aligning the central flow surface of each stage runner with the central flow surfaces of the front and rear annular flow channels, a continuous, smooth, and abrupt airflow channel is formed. This minimizes the impact losses, eddy current losses, and mixing losses caused by diffusion, contraction, and abrupt changes in direction during interstage transitions, laying the core flow channel foundation for achieving a measured overall conversion efficiency of up to 89.8%. This design also endows the runner with excellent system compatibility and versatility, enabling it to be seamlessly integrated as a standard module into pneumatic turbine systems of different stages based on the same "unified flow channel" design concept.

[0049] The above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A runner for a pneumatic turbine, characterized in that: The device includes a rotor hub (1), a rotor outer ring (2), and multiple airfoil blades (3). The airfoil blades (3) are evenly spaced between the rotor hub (1) and the rotor outer ring (2) along the circumferential direction. A blade flow channel (4) is formed between the outer circumferential surface of the rotor hub (1) and the inner circumferential surface of the rotor outer ring (2). The blade flow channel (4) is a gradually expanding flow channel. The airfoil blades (3) are three-dimensional twisted airfoil structures. The airfoil blades (3) are located in the blade flow channel (4). A sub-flow channel (8) extending along the airflow direction is formed between two adjacent airfoil blades (3). The airflow direction at the inlet of the sub-flow channel (8) is configured to be close to the tangential direction of the rotor, and the airflow direction at the outlet of the sub-flow channel (8) is configured to be close to the axial direction of the rotor. The leading edge of the airfoil blade is elliptical, and the trailing edge is circular; The central flow surface of the blade flow channel is a cylindrical surface, and the diameter of the cylindrical surface is equal to the diameter of the central flow surface of the nozzle flow channel of the adjacent seat ring in the pneumatic turbine.

2. The runner for a pneumatic turbine according to claim 1, characterized in that: The airfoil blade (3) has an outer inlet installation angle of 55 degrees to 65 degrees and an outer outlet installation angle of 10 degrees to 12 degrees; the inner inlet installation angle is -60 degrees to -55 degrees and the inner outlet installation angle is 12 degrees to 14 degrees.

3. The runner for a pneumatic turbine according to claim 2, characterized in that: It includes four rotors, namely a first-stage rotor, a second-stage rotor, a third-stage rotor, and a fourth-stage rotor arranged in sequence along the airflow direction. The first-stage rotor includes a first-stage blade, the second-stage rotor includes a second-stage blade, the third-stage rotor includes a third-stage blade, and the fourth-stage rotor includes a fourth-stage blade.

4. The runner for a pneumatic turbine according to claim 3, characterized in that: The first-stage rotor blade has an outer inlet installation angle of 61.39 degrees, an outer outlet installation angle of 11.47 degrees, an inner inlet installation angle of -59.4 degrees, and an inner outlet installation angle of 13.54 degrees.

5. A runner for a pneumatic turbine according to claim 3, characterized in that: The second-stage rotor blade has an outer inlet installation angle of 60.40 degrees, an outer outlet installation angle of 11.44 degrees, an inner inlet installation angle of -58.36 degrees, and an inner outlet installation angle of 13.58 degrees.

6. A runner for a pneumatic turbine according to claim 3, characterized in that: The three-stage propeller blade has an outer wing inlet installation angle of 59.33 degrees, an outer wing outlet installation angle of 11.41 degrees, an inner wing inlet installation angle of -57.24 degrees, and an inner wing outlet installation angle of 13.62 degrees.

7. A runner for a pneumatic turbine according to claim 3, characterized in that: The fourth-stage propeller blade has an outer wing inlet installation angle of 58.16 degrees, an outer wing outlet installation angle of 11.37 degrees, an inner wing inlet installation angle of -56.02 degrees, and an inner wing outlet installation angle of 13.67 degrees.

8. A runner for a pneumatic turbine according to claim 3, characterized in that: Each stage of the runner is provided with a seat ring (15) at its upstream end. The seat ring has a nozzle flow channel. Airfoil guide vanes are evenly spaced along the circumferential direction in the nozzle flow channel. The outer outlet installation angle of the airfoil guide vanes is 12 to 15 degrees, and the inner outlet installation angle of the airfoil guide vanes is 10 to 13 degrees.

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