Method for regulating rotational inertia to enhance shafting stability and ocean energy generator set

Abstract

The invention provides a method for regulating and controlling rotational inertia to enhance shafting stability and an ocean energy generator set. The method comprises the steps that at least one centrifugal sliding block speed stabilizing device is fixedly installed in the circumferential direction of a main shaft, and the main shaft is connected with an impeller; the centrifugal sliding block speed stabilizing device is composed of a sliding rod, a sliding block arranged on the sliding rod in a sleeving mode and a plurality of elastic reset mechanisms used for controlling the sliding block to move in the radial direction. One end of the sliding rod is fixed on the main shaft through a flange or a bolt, the other end radially extends towards the main shaft, and a limiting plate is arranged at the tail end to control the movement range of the sliding block; the elastic reset mechanism is arranged between the main shaft and the sliding block and between the tail end of the sliding rod and the sliding block. The rotating speed is adjusted in a self-adaptive mode through a completely passive mechanical structure, rotating speed fluctuation of the rotating wheel caused by fluid flow speed changes is effectively restrained, the shaft system stability of the system is improved, vibration in the operation process is reduced, material fatigue consumption caused by frequent rotating speed changes is reduced, and the service life of the rotating wheel is prolonged.

Description

Technical Field

[0001] This invention belongs to the field of fluid machinery and ocean energy power generation technology, and particularly relates to a method for regulating rotational inertia to enhance shaft system stability and an ocean energy generator set. Background Technology

[0002] The core energy conversion component of ocean energy power generation devices such as tidal current energy and ocean current energy is the water turbine, which captures fluid kinetic energy through impellers and drives a generator to produce electricity. However, the fluid flow velocity in nature (such as ocean waves and tides) has significant randomness and fluctuation, causing frequent changes in the turbine speed. This speed fluctuation can cause a series of problems: First, it directly leads to instability in the frequency and voltage of the generator's output power, affecting power quality; second, periodic speed fluctuations and the resulting torque pulsations are transmitted to the entire drive shaft system, causing unit vibration and noise, reducing the service life of mechanical components, and even causing structural fatigue damage; finally, severe speed fluctuations may cause the water turbine to deviate from its optimal efficiency operating range, reducing energy capture efficiency.

[0003] To address these issues, existing technologies often employ active control strategies, such as pitch control or load regulation via power electronics. While effective, these methods suffer from drawbacks including system complexity, high cost, reliance on external energy input, and low reliability in harsh marine environments. Furthermore, some inertial control devices have been proposed, but they are often structurally complex or fail to adequately account for drag losses caused by the movement of additional components in the fluid, potentially negatively impacting turbine efficiency.

[0004] Therefore, there is an urgent need in this field for a method that is simple in structure, requires no external energy input, can adapt to fluid changes and effectively suppress rotational speed fluctuations, and improve shaft stability, so as to provide a foundation for efficient and stable marine energy generator sets. Summary of the Invention

[0005] The purpose of this invention is to provide a method for regulating rotational inertia to enhance shaft system stability and an ocean energy generator set. The aim is to adaptively adjust the system's rotational inertia through a completely passive mechanical structure to smooth out rotational speed fluctuations caused by changes in fluid velocity, thereby improving shaft system operational stability, reducing vibration, and extending equipment lifespan, while ensuring the device itself has low fluid resistance characteristics. When the system speed increases due to fluid drive, the slider moves outward under centrifugal force, overcoming elastic force, increasing the overall rotational inertia of the system. According to the principle of conservation of angular momentum, this suppresses excessively rapid increases in speed. When the system speed decreases, the elastic force drives the slider inward, reducing the system's rotational inertia and mitigating the decrease in speed. Through this passive feedback mechanism, adaptive suppression of speed fluctuations is achieved.

[0006] This invention provides a method for regulating rotational inertia to enhance shaft system stability. At least one centrifugal slider stabilizing device is fixedly installed circumferentially along the main shaft, which is connected to an impeller. The centrifugal slider stabilizing device consists of a slide rod, a slider mounted on the slide rod, and several elastic reset mechanisms for controlling the radial movement of the slider. One end of the slide rod is fixed to the main shaft by a flange or bolts, and the other end extends radially toward the main shaft, with a limiting plate at the end to control the slider's range of motion. The elastic reset mechanisms are located between the main shaft and the slider, and between the end of the slide rod and the slider.

[0007] Furthermore, the plurality of centrifugal slider speed stabilizing devices are arranged at equal intervals along the circumference of the main shaft.

[0008] Furthermore, the cross-sectional shape of the slide bar matches the shape of the slider channel, and restricts the slider's rotational motion around the slide bar.

[0009] Furthermore, the main body of the slider has a rotationally symmetric structure, obtained by rotating a generatrix of revolution, which includes: The first baseline, located at the front end of the slider structure, is elliptical in shape; The second baseline, located at the rear end of the slider structure, is parabolic in shape.

[0010] Furthermore, a coordinate system is established with the center of the slider, and the shape of the generatrix of the slider body is determined by the slider length L0 and the slider width D; The curve equation for the first baseline segment is: ; The curve equation for the second baseline segment is: .

[0011] Furthermore, the mass of a single slider is m, and the ratio of the mass of a single blade of the impeller to the mass of a single blade is m / M≤1 / 2.

[0012] Furthermore, the elastic reset mechanism (33) is made of springs or elastic ropes.

[0013] The present invention also provides an ocean energy generator set, including a main shaft, an impeller, and a centrifugal slider speed stabilizing device configured according to the method of regulating rotational inertia to enhance shaft system stability.

[0014] With the above solution, the method for enhancing the stability of the shafting by regulating the moment of inertia and the marine energy generating set fully utilize the balance between the centrifugal force of the slider itself and the elastic restoring force. Without external energy input and complex control systems, it can automatically adjust the moment of inertia according to the speed change, with rapid response and high reliability. By suppressing speed fluctuations, the torque pulsation and vibration amplitude of the transmission chain are significantly reduced, the shafting stability of the entire generating set is improved, and the service life of key components such as bearings and gearboxes is extended. At the same time, the slider in the present invention adopts a unique bionic streamline design, which greatly reduces the resistance during movement in the fluid and minimizes the impact of the speed stabilizing device on the efficiency of the water turbine itself. Moreover, the device has a simple structure, low manufacturing cost, is convenient for installation or modification on the existing water turbine structure, and has a wide range of applications. It can not only be used in marine energy generating sets, but also be extended to other fluid machinery working in a fluctuating fluid environment.

[0015] The above description is only an overview of the technical solution of the present invention. In order to be able to more clearly understand the technical means of the present invention and implement it according to the content of the specification, the following will be described in detail with reference to the preferred embodiments of the present invention and the accompanying drawings. Brief Description of the Drawings

[0016] Figure 1 is a three-dimensional schematic diagram of the method for enhancing the stability of the shafting by applying the regulation of the moment of inertia in the embodiment of the present invention; Figure 2 is a three-dimensional schematic diagram of the centrifugal slider speed stabilizing device in the embodiment of the present invention; Figure 3 is a schematic diagram of the slider's rotating generatrix in the embodiment of the present invention.

[0017] Reference numerals in the figure: 1 - main shaft; 2 - impeller; 3 - centrifugal slider speed stabilizing device; 31 - slide bar; 32 - slider; 33 - elastic reset mechanism; 321 - rotating generatrix at the front end of the slider; 322 - rotating generatrix at the rear end of the slider. Detailed Embodiments

[0018] The following will further describe in detail the specific embodiments of the present invention in conjunction with the accompanying drawings and embodiments. The following embodiments are used to illustrate the present invention, but are not used to limit the scope of the present invention.

[0019] Refer Figures 1 to 3As shown, this embodiment provides a method for regulating rotational inertia to enhance shaft system stability. At least one centrifugal slider stabilizing device 3 is fixedly installed circumferentially along the main shaft 1 of the marine energy generator set. The main shaft 1 is connected to the impeller 2. The centrifugal slider stabilizing device 3 consists of a slide rod 31, a slider 32 fitted on the slide rod 31, and several elastic reset mechanisms 33 for controlling the radial movement of the slider 32. The slide rod is a cylindrical structure with a length of L. One end of the slide rod 31 is fixed to the main shaft 1 by a flange or bolt, and the other end extends radially toward the main shaft. The extension distance is determined by the length L of the slide rod, and a limiting plate is set at the end to control the movement range of the slider 32 and prevent the slider from coming off when the centrifugal force is too large. The elastic reset mechanism 33 is set between the main shaft 1 and the slider 32, and between the end of the slide rod and the slider 32, to provide radial elastic restoring force for the slider.

[0020] This centrifugal slider speed stabilization device improves shaft system stability through the radial movement of the slider. Specifically, when the fluid velocity increases, causing the system speed to rise, the slider moves outward along the slide bar under centrifugal force, increasing the system's moment of inertia and thus suppressing excessively rapid increases in speed. When the speed decreases, the elastic reset mechanism pulls the slider back, reducing the moment of inertia and mitigating the speed drop. This invention effectively smooths out rotor speed fluctuations caused by changes in fluid velocity through a completely passive mechanical structure that adaptively adjusts the speed. This improves shaft system stability, reduces vibration during operation, and minimizes material fatigue consumption caused by frequent speed changes, thereby extending rotor lifespan. Furthermore, the device is simple in structure, highly reliable, and can be widely applied in various fluid machinery fields, such as marine energy generator sets.

[0021] In this embodiment, the three centrifugal slider speed stabilizing devices 3 are arranged at equal intervals along the circumference of the main shaft.

[0022] In this embodiment, the cross-section of the slide bar can be square or other non-circular. The shape of the slide bar's cross-section needs to match the shape of the slider channel and restrict the slider's rotational movement around the slide bar. This ensures smooth radial sliding of the slider while effectively preventing its rotation around the slide bar.

[0023] The slider's shape design is as follows Figure 3 As shown, the slider adopts a biomimetic structural design to reduce flow resistance. The main body of slider 33 has a rotationally symmetric structure, and its main body is a streamlined rotationally symmetric body formed by rotating a generatrix of revolution. This generatrix of revolution consists of two smoothly connected curves: The first baseline 321 (the upstream section) is located at the front end of the slider structure and is elliptical in shape; The second baseline 322 (wake section) is located at the rear end of the slider structure and is parabolic in shape.

[0024] A coordinate system is established with the center of the slider. The shape of the slider's generatrix of revolution is determined by the slider length L0 and the slider width D. Its precise shape is defined by the following equation: The curve equation of the first baseline segment (elliptical segment) is: ; The equation of the curve for the second baseline segment (parabolic segment) is: ; Where L0 is the length of the slider and D is the width of the slider. This biomimetic shape can effectively guide the fluid to smoothly bypass the slider, significantly reducing pressure drag and vortex shedding, thereby minimizing its negative impact on turbine efficiency.

[0025] The slider is mounted on the slide rod. Its mass m is carefully designed so that the mass of a single slider is m, and the ratio of the mass of a single impeller blade M is m / M≤1 / 2, in order to avoid the negative effects of excessive inertia.

[0026] In this embodiment, the elastic reset mechanism 33 is made of materials such as springs or elastic ropes that have linear elasticity within the working range, and can control the radial movement of the slider. In this embodiment, the elastic reset mechanism uses a high-strength, corrosion-resistant elastic rope. One rope is connected between the spindle flange and the inner end face of the slider, and the other is connected between the limiting plate at the end of the slide rod and the outer end face of the slider, providing the slider with an elastic restoring force that always points towards the spindle axis.

[0027] When the velocity of ocean waves or tidal currents increases, driving the impeller and increasing the spindle speed, the centrifugal force on the slider increases. When the centrifugal force exceeds the restoring force provided by the elastic reset mechanism, the slider moves radially outward along the slide bar, causing an increase in the moment of inertia of the entire rotor system (spindle, impeller, and slider). According to the principle of conservation of angular momentum, this will inhibit a further rapid increase in the spindle speed. Conversely, when the fluid velocity decreases and the spindle speed decreases, the centrifugal force on the slider weakens, and the restoring force of the elastic reset mechanism pulls the slider towards the spindle axis, reducing the system's moment of inertia and thus slowing down the decreasing trend of the speed. Through this adaptive radial movement of the slider, the system speed is stabilized within a relatively narrow range, effectively improving shaft stability and reducing vibration and fatigue damage.

[0028] This invention also provides a marine energy generator set, including a main shaft, an impeller, and a centrifugal slider speed stabilizing device configured according to the method for regulating rotational inertia to enhance shaft system stability. The generator set utilizes the aforementioned method for regulating rotational inertia to enhance shaft system stability, thereby achieving safe and stable operation of the unit.

[0029] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for adjusting rotational inertia to enhance shaft system stability, characterized in that, At least one centrifugal slider speed stabilizing device (3) is fixedly installed circumferentially along the main shaft (1), and the main shaft (1) is connected to the impeller (2); the centrifugal slider speed stabilizing device (3) consists of a slide rod (31), a slider (32) fitted on the slide rod (31), and several elastic reset mechanisms (33) for controlling the radial movement of the slider (32); one end of the slide rod (31) is fixed to the main shaft (1) by a flange or bolt, and the other end extends radially toward the main shaft and is provided with a limiting plate at the end to control the movement range of the slider (32); the elastic reset mechanism (33) is provided between the main shaft (1) and the slider (32), and between the end of the slide rod and the slider (32).

2. The method for adjusting the moment of inertia to enhance shaft system stability according to claim 1, characterized in that, Multiple centrifugal slider speed stabilizing devices (3) are arranged at equal intervals along the circumference of the main shaft.

3. The centrifugal slider speed stabilizing device according to claim 1, characterized in that, The cross-sectional shape of the slide bar matches the shape of the slider channel and restricts the slider's rotation around the slide bar.

4. The method for adjusting the moment of inertia to enhance shaft system stability according to claim 2, characterized in that, The slider (33) has a rotationally symmetric structure and is obtained by rotating a generatrix, which includes: The first baseline (321) is located at the front end of the slider structure and is elliptical in shape; The second baseline (322) is located at the rear end of the slider structure and is parabolic in shape.

5. The method for adjusting the moment of inertia to enhance shaft system stability according to claim 4, characterized in that, A coordinate system is established with the center of the slider as the reference point. The shape of the rotation generatrix of the slider body is determined by the slider length L0 and the slider width D. The curve equation for the first baseline segment is: ； The curve equation for the second baseline segment is: 。 6. The method for adjusting the moment of inertia to enhance shaft system stability according to claim 4, characterized in that, The mass of a single slider is m, and the ratio of the mass of a single blade of the impeller to the mass of a single blade is m / M≤1 / 2.

7. The method for adjusting the moment of inertia to enhance shaft system stability according to claim 1, characterized in that, The elastic reset mechanism (33) is made of springs or elastic ropes.

8. A marine energy generator set, characterized in that, It includes a main shaft, an impeller, and a centrifugal slider speed stabilizing device provided according to the method of adjusting rotational inertia to enhance shaft system stability as described in any one of claims 1-7.

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