A device for applying sudden unbalanced loads to a simulated rotor

Abstract

This invention discloses a device for applying sudden unbalanced loads to a simulated rotor, comprising a wheel, a high-temperature ceramic heating element, a strong magnetic block, an unbalanced mass block, an unbalanced mass compensation block, a strong magnetic block fixing screw, a conductive slip ring, a support frame, a rotating shaft, and bearings. The high-temperature ceramic heating element, the strong magnetic block, and the unbalanced mass block (or unbalanced mass compensation block) are sequentially installed radially from the inside out in a rectangular groove on the wheel, and the high-temperature ceramic heating element is powered through a conductive slip ring mounted on the rotating shaft. By controlling the temperature of the strong magnetic block, the magnetic attraction force on the unbalanced mass block or the unbalanced mass compensation block is indirectly controlled, thereby achieving the sudden application or compensation of unbalanced loads on the rotor. This invention makes the application of unbalanced loads highly accurate and wide-range, allows for compensation of residual unbalance after application, and makes the repeated testing process more convenient and faster.

Description

Technical Field

[0001] This invention belongs to the field of aero-engine simulated rotor testing technology, and specifically relates to a device for applying sudden unbalanced loads to simulated rotors. Background Technology

[0002] Aero engines operate at high and widely varying speeds, experience complex load environments, and undergo frequent changes in motion. Their high-speed rotating rotor systems are prone to excessive vibration under extreme loads, which can severely impact the engine's normal and stable operation and structural safety. Taking a civilian high-bypass turbofan engine as an example, when the engine is struck by a bird or other foreign object, fan blades may break off and fly out (i.e., fan blade loss), causing severe rotor-stator rubbing, shaft seizure, and other hazardous failures, which in turn pose a serious threat to the structural safety of the engine and even the aircraft. Therefore, to further improve the safety and reliability of engines under harsh operating conditions, it is essential to conduct research on the dynamic behavior of the entire engine and its rotor system under blade loss excitation.

[0003] Early experimental research on the problem of engine fan blade loss mainly focused on rigorous blade loss tests and casing containment tests. However, such whole-engine tests are often extremely costly and expensive. In order to minimize development costs, applying sudden unbalanced loads to a simulated rotor system to study its unbalanced response characteristics and impact dynamics is an effective and labor-saving research method.

[0004] Existing and publicly disclosed rotor unbalanced load application devices can be mainly classified into the following types:

[0005] One type is the blade clamping / release mechanism disclosed in patents with authorization announcement numbers "CN113280979B", "CN106611553B", and "CN111947836B". This type of mechanism clamps or releases the simulated blade by arranging corresponding mechanical or electromagnetic devices on the wheel. Its disadvantage is that the additional device structure is relatively complex, and it cannot compensate for the unbalance of the rotor system after applying an unbalanced load. The second type is the blade melting and release mechanism disclosed in patents with authorization announcement number "CN109580138B" and application publication number "CN 114705364A". This type of mechanism melts the connection line between the simulated blade and the wheel to apply the unbalance by using an electric heating element or a laser ignition device. The main problem is that the former also cannot compensate for the rotor unbalance, and the latter is relatively cumbersome when replacing the unbalanced mass block for repeated tests. Thirdly, there is the tangential impact loading mechanism used in the paper "Theoretical and experimental investigation on the sudden unbalance and rub-impact in rotor system caused by bladeoff". This mechanism relies on a tangential impact device to cut the unbalanced mass block laterally from the narrower shaft diameter to apply the unbalanced load. However, its obvious limitation is that the application of the unbalanced load is accompanied by a large additional impact effect. Summary of the Invention

[0006] To overcome the shortcomings of existing rotor imbalance application technologies, such as complex structure, significant additional impact effects during imbalance application, inability to compensate for imbalance after application, and cumbersome replacement process of the imbalance mass block, this invention provides a device for applying sudden unbalanced loads to simulate rotors. This device can accurately apply a specific amount of imbalance at a specific speed without introducing additional interference during the imbalance application process. Furthermore, for supercritical rotors, it can compensate for residual imbalance after application, ensuring the rotor can smoothly decelerate past the critical point. In addition, the imbalance mass block of the device is easy to replace, facilitating repeated testing.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] A device for applying sudden unbalanced loads to a simulated rotor includes a wheel, a high-temperature ceramic heating element, a strong magnetic block, an unbalanced mass block, an unbalanced mass compensation block, a strong magnetic block fixing screw, a conductive slip ring, a support frame, a shaft, and bearings. The support frame, bearings, shaft, and wheel form a simulated rotor system used to simulate the cantilever section of a high-bypass turbofan engine fan rotor. The high-temperature ceramic heating element, strong magnetic block, unbalanced mass block, unbalanced mass compensation block, strong magnetic block fixing screw, and conductive slip ring form a sudden unbalanced load application system used to apply and compensate for rotor unbalanced loads.

[0009] The aforementioned device for applying a sudden unbalanced load has a wheel with a certain number of dynamic balancing holes arranged circumferentially, and two symmetrical wheel grooves opened on opposite sides radially. The dynamic balancing holes are used to dynamically balance the entire rotor system after the unbalanced load application device is installed, reducing the initial unbalance of the rotor; the wheel grooves are used to place the high-temperature ceramic heating element, the strong magnetic block, the unbalanced mass block, and the unbalanced mass compensation block.

[0010] In the aforementioned device for applying a sudden unbalanced load, the high-temperature ceramic heating element is placed in two grooves on the wheel, with one surface in contact with the bottom surface of the groove and the other surface in contact with the bottom surface of the strong magnetic block, for heating the strong magnetic block.

[0011] In the aforementioned device for applying a sudden unbalanced load, the strong magnetic block is also placed in the two grooves of the wheel. It has very strong magnetism at room temperature, but loses some magnetism at high temperature. Therefore, by changing its temperature, its magnetic attraction force can be changed, thereby achieving the fixation and release of the unbalanced mass block and the unbalanced mass compensation block.

[0012] In the aforementioned device for applying a sudden unbalanced load, the unbalanced mass block and the unbalanced mass compensation block are respectively attracted to strong magnetic blocks in the grooves on both sides of the wheel. The unbalanced mass block and the unbalanced mass compensation block have the same structural form, the difference being that the former can apply the unbalance by detaching from the wheel, while the latter can compensate for the unbalance by detaching from the wheel successively.

[0013] The aforementioned device for applying a sudden unbalanced load includes a conductive slip ring comprising rotor wires and stator wires, wherein the rotor wires rotate with the shaft, while the stator wires do not rotate. The conductive slip ring allows power to be supplied to the high-temperature ceramic heating elements in the grooves on both sides of the disc while the rotor is rotating.

[0014] Furthermore, the wheel groove has side holes on both sides, and these side holes are threaded holes to facilitate the screwing in of the strong magnet fixing screw.

[0015] Furthermore, the axis of the side hole of the wheel groove forms a 45° angle with the side of the groove.

[0016] Furthermore, the dynamic balancing hole of the wheel is a threaded through hole.

[0017] Furthermore, the strong magnetic block, the unbalanced mass block, and the unbalanced mass compensation block are all N52 neodymium iron boron magnets, which possess excellent magnetic properties.

[0018] Furthermore, a side hole for the strong magnetic block is provided on the side where it fits into the groove of the wheel. The strong magnetic block can be fixed radially, circumferentially, and axially by screwing the fixing screw into the side hole.

[0019] Furthermore, the axis of the side hole of the strong magnetic block forms a 45° angle with the side surface of the strong magnetic block.

[0020] Furthermore, the fixing screw for the strong magnetic block is an internal hexagon screw.

[0021] Furthermore, the lead wire of the high-temperature ceramic heating element is connected to the rotor wire of the conductive slip ring.

[0022] Furthermore, the conductive slip ring has two pairs of rotor wires arranged on opposite radial sides, which respectively form relatively independent power supply circuits with the high-temperature ceramic heating elements on both sides of the wheel, facilitating the heating of the strong magnetic blocks on one side of the wheel.

[0023] Furthermore, the rotor wires of the conductive slip ring are glued to the wheel and shaft, and the rotor wires on both sides are arranged as symmetrically as possible to minimize the initial imbalance of the rotor.

[0024] The present invention also provides a method for using the device for applying a sudden unbalanced load to a simulated rotor as follows:

[0025] Step 1: Install the imbalance application device on the wheel and the shaft, and perform low-speed dynamic balancing on the rotor through the dynamic balancing holes of the wheel to ensure that the rotor system has a small initial imbalance.

[0026] Step 2: When the rotor reaches a specific speed, keep the rotor speed constant and supply power to the high-temperature ceramic heating element on the unbalanced application side. This causes the temperature of the strong magnetic block on that side to rise, thereby losing some of its magnetism. As a result, the magnetic attraction force on the unbalanced mass block is less than the centrifugal force, causing it to fly off the wheel and realize the sudden application of the unbalanced load.

[0027] Step 3: After the unbalanced load is applied, power is supplied to the high-temperature ceramic heating element on the unbalanced compensation side, so that the unbalanced mass compensation block on that side also flies off the wheel disk, thereby realizing the compensation of the unbalance of the rotor system.

[0028] Step four: After the rotor test system decelerates and stops, simply reinstall the new unbalanced mass block and unbalanced mass compensation block to repeat the rotor unbalanced load sudden application test.

[0029] By adopting the above technical solution, the present invention has the following beneficial effects:

[0030] (1) The present invention provides a device for applying sudden unbalanced load to simulate rotor. The device uses the strong magnetic properties of neodymium iron boron magnets to adsorb and fix the unbalanced mass block, and uses its high-temperature demagnetization properties to make the unbalanced mass block fall off and be thrown out. When the unbalanced mass block is thrown off, it is only subjected to the radial load along the wheel disk, without the influence of external additional impact load. It can simulate the fly-off process of engine fan blades more realistically and realize the sudden application of unbalanced load to rotor system.

[0031] (2) The present invention provides a device for applying a sudden unbalanced load to a simulated rotor, which can reduce the magnetic attraction force on the unbalanced mass block at a constant rotational speed to make it fly off, thus enabling precise control of the rotor speed when the unbalanced load is applied. At the same time, by adjusting the size of the unbalanced mass block and controlling the fly-off speed of the unbalanced mass block, it is possible to apply various unbalanced quantities within a wide range of rotational speeds.

[0032] (3) The present invention provides a device for applying a sudden unbalanced load to a simulated rotor, wherein an unbalanced application device and an unbalanced compensation device are respectively arranged on opposite radial sides of the rotor disc, which can independently realize the sudden application and compensation of the unbalance. For supercritical rotor systems, it can effectively avoid excessive resonance response that could damage the test equipment when the rotor decelerates past the critical point with a large unbalance, and ensure that the supercritical rotor test system can decelerate and stop smoothly and safely after a sudden unbalanced load is applied.

[0033] (4) The present invention provides a device for applying sudden unbalanced load to simulate rotor. The unbalanced mass block and the unbalanced mass compensation block are directly fixed on the groove of the wheel disk by magnetic attraction, without the need for additional fixing mechanism. Therefore, its replacement and installation process is more convenient and faster, and it is easy to carry out the rotor sudden unbalance test repeatedly. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the overall structure of a device for applying a sudden unbalanced load to a simulated rotor according to the present invention;

[0035] Figure 2 This is a schematic diagram of the power supply wire arrangement of the present invention;

[0036] Figure 3 This is a schematic diagram of the installation configuration of the strong magnetic block, unbalanced mass block, etc. of the present invention on the wheel;

[0037] Figure 4 This is a cross-sectional schematic diagram of the strong magnetic block fixing method of the present invention;

[0038] Figure 5 This is a schematic diagram of the wheel groove and its side hole structure of the present invention;

[0039] Figure 6 This is a schematic diagram of the strong magnetic block structure of the present invention;

[0040] In the diagram, 1-disc; 2-high-temperature ceramic heating element; 3-strong magnetic block; 4-unbalanced mass block; 5-unbalanced mass compensation block; 6-strong magnetic block fixing screw; 7-conductive slip ring; 8-support frame; 9-shaft; 10-bearing; 11-disc groove; 111-disc groove side hole; 12-disc dynamic balancing hole; 31-strong magnetic block side hole; 71-rotor wire; 72-stator wire. Detailed Implementation

[0041] The present disclosure will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the disclosure. Furthermore, it should be noted that, for ease of description, only the parts relevant to the present disclosure are shown in the accompanying drawings.

[0042] See Figures 1-6 The present invention provides a device for applying a sudden unbalanced load to a simulated rotor, comprising a wheel 1, a high-temperature ceramic heating element 2, a strong magnetic block 3, an unbalanced mass block 4, an unbalanced mass compensation block 5, a strong magnetic block fixing screw 6, a conductive slip ring 7, a support frame 8, a rotating shaft 9, and a bearing 10.

[0043] The wheel 1 has a certain number of dynamic balancing holes 12 arranged along its circumference. These dynamic balancing holes 12 are threaded through holes, allowing screws of different lengths to be screwed into them at different positions to achieve dynamic balancing of the rotor system, ensuring a small initial imbalance after the unbalanced load application device is installed. The wheel 1 has two identical rectangular grooves 11 on opposite radial sides for housing the high-temperature ceramic heating element 2, the strong magnetic block 3, the unbalanced mass block 4, and the unbalanced mass compensation block 5. Furthermore, two inclined side holes 111 are provided on both sides of the grooves 11. These side holes 111 are also threaded holes, with their axes forming a 45° angle with the side of the groove 11, for screwing in strong magnetic block fixing screws 6 to secure the strong magnetic block 3.

[0044] The high-temperature ceramic heating element 2 is placed at the lowest end of the wheel groove 11, with its lower surface in contact with the bottom surface of the wheel groove 11 and its upper surface in contact with the bottom surface of the strong magnetic block 3. When the high-temperature ceramic heating element 2 is connected to a power source, its dry-burning surface temperature can reach up to about 480°C, which can effectively heat and demagnetize the strong magnetic block 3.

[0045] The strong magnetic block 3 is made of N52 neodymium iron boron magnet, which has very strong magnetism at room temperature, enabling it to firmly attract the unbalanced mass block 4 and the unbalanced mass compensation block 5. When the temperature rises, its magnetism will partially weaken, thereby reducing the magnetic attraction and allowing the release of the unbalanced mass block 4 or the unbalanced mass compensation block 5. The side of the strong magnetic block 3 that fits into the wheel groove 11 has a strong magnetic block side hole 31. The axis of this hole is at the same 45° angle as its side. When the strong magnetic block fixing screw 6 is screwed into the wheel groove side hole 111, the screw head can push into the strong magnetic block side hole 31, thereby fixing the strong magnetic block 3 and the high-temperature ceramic heating element 2 radially, circumferentially, and axially.

[0046] The unbalanced mass block 4 and the unbalanced mass compensation block 5 have identical structures and are both made of N52 neodymium iron boron magnets to ensure maximum magnetic attraction between them and the strong magnetic block 3 when their dimensions are fixed. The difference between the two is that the unbalanced mass block 4 can be detached from the wheel 1 to achieve a sudden increase in rotor unbalance, while the unbalanced mass compensation block 5 can be detached from the wheel 1 to compensate for rotor unbalance.

[0047] The conductive slip ring 7 is fixed to the rotating shaft 9 and is used to supply power to the high-temperature ceramic heating element 2 when the rotor is rotating. Rotor wires 71 and stator wires 72 are led out from both ends of the conductive slip ring 7. The former rotates at high speed with the rotating shaft 9 and is connected to the leads of the high-temperature ceramic heating element 2; the latter does not rotate with it and is connected to an external power source. The heating elements located on opposite radial sides of the disc have independent power supply circuits, thus allowing for relatively independent heating of a single-sided strong magnetic block, ensuring that the unbalanced mass block 4 and the unbalanced mass compensation block 5 can detach at different times. To prevent the rotor wires 71 from tangling and knotting during rotor rotation, they can be glued to the surfaces of the disc 1 and the rotating shaft 9. When gluing, the wires on opposite radial sides of the disc should be arranged symmetrically to minimize additional imbalance.

[0048] The specific steps for using the device for applying a sudden unbalanced load to a simulated rotor provided by this invention are as follows:

[0049] Step 1: Install the high-temperature ceramic heating element 2, strong magnetic block 3, unbalanced mass block 4, unbalanced mass compensation block 5, strong magnetic block fixing screw 6 and conductive slip ring 7 on the wheel disk 1 and the rotating shaft 8 to form an unbalanced load application device. Then, use the wheel disk dynamic balancing hole 12 to dynamically balance the rotor system and reduce the initial unbalance of the rotor.

[0050] Step 2: When the rotor reaches a specific speed, the speed is kept constant. Power is supplied to the high-temperature ceramic heating element 2 on the unbalanced side of the wheel 1, so that the temperature of the strong magnetic block 3 on that side rises and loses part of its magnetism. When the magnetic attraction force on the unbalanced mass block 4 on that side is less than the centrifugal force, it will fly off the wheel 1, realizing the sudden addition of the unbalanced load on the rotor.

[0051] Step 3: After the rotor unbalanced load is suddenly applied, power is supplied to the high-temperature ceramic heating element 2 on the other side, so that the unbalanced mass compensation block 5 is detached from the wheel disk 1, thereby compensating for the rotor unbalanced load.

[0052] Step four: After the test is completed, replace the unbalanced mass block 4 and the unbalanced mass compensation block 5 to start a new round of unbalanced load application test. The whole replacement process is simple and quick.

[0053] As mentioned above, the key issue of the device for applying a sudden unbalanced load to a simulated rotor provided by the present invention lies in whether the magnetic attraction force provided by the strong magnetic block 3 to the unbalanced mass block 4 and the unbalanced mass compensation block 5 can exceed the centrifugal force they experience. The feasibility of the invention will be demonstrated below with a specific embodiment.

[0054] In this embodiment, the dimensions of the strong magnetic block 3 are 30mm × 20mm × 20mm, the dimensions of the unbalanced mass block 4 and the unbalanced mass compensation block 5 are both 30mm × 20mm × 1.1mm, the diameter of the wheel 1 is 300mm, the speed at which the unbalanced load on the simulated rotor is applied is set to 4000rpm, and the density of the neodymium iron boron magnet is 7.5g / cm³. 3 Based on the formula for estimating the magnetic force of neodymium iron boron magnets (magnetic force ≈ magnet weight × 150), the magnetic attraction between the strong magnetic block 3 and the unbalanced mass block 4 or the unbalanced mass compensation block 5 can be calculated to be approximately 132 N; while the centrifugal force experienced by the unbalanced mass block 4 and the unbalanced mass compensation block 5 at a given rotational speed is approximately 130 N (centrifugal force = unbalanced block mass × wheel radius × angular velocity). 2 The magnetic force exerted on the unbalanced mass block 4 and the unbalanced mass compensation block 5 is less than the magnetic attraction force they experience. Therefore, in this embodiment, at room temperature, it can be ensured that the unbalanced mass block 4 and the unbalanced mass compensation block 5 do not detach from the wheel 1 within a speed range of up to 4000 rpm. When it is necessary for them to detach, it is only necessary to control the heating temperature and heating time of the high-temperature ceramic heating element 2 so that the magnetic attraction force between the strong magnetic block 3 and the unbalanced mass block 4 or the unbalanced mass compensation block 5 is less than the centrifugal force experienced by the latter.

[0055] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes, modifications or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A device for applying a sudden unbalanced load to a simulated rotor, characterized in that, The device for applying sudden unbalanced load includes a wheel, a high-temperature ceramic heating element, a strong magnetic block, an unbalanced mass block, an unbalanced mass compensation block, a strong magnetic block fixing screw, a conductive slip ring, a support frame, a rotating shaft, and bearings. The wheel has a certain number of wheel dynamic balance holes arranged circumferentially near the rim, and two symmetrical rectangular wheel grooves are opened on opposite sides radially. The high-temperature ceramic heating element and the strong magnetic block are installed in the grooves of the wheel on both sides of the wheel from radial to radial from the inside to the outside. The strong magnetic block on one side of the wheel is attracted to the unbalanced mass block, and the strong magnetic block on the other side is attracted to the unbalanced mass compensation block. The conductive slip ring is mounted on the rotating shaft, with rotor wires and stator wires leading out from its two ends respectively. The rotor wires are connected to the leads of the high-temperature ceramic heating element and rotate with the rotating shaft, while the stator wires are connected to an external power source and do not rotate with the rotating shaft. The strong magnetic block, the unbalanced mass block, and the unbalanced mass compensation block are all N52 neodymium iron boron strong magnets, and the unbalanced mass block and the unbalanced mass compensation block have the same structural form. The rotor wires of the conductive slip ring are firmly attached to the surfaces of the wheel and shaft with adhesive, and the rotor wires on the radially opposite sides of the wheel are arranged symmetrically. The strong magnetic block fixing screw is screwed into the side hole of the wheel groove, and the head of the strong magnetic block fixing screw passes through the side hole of the wheel groove and pushes into the side hole of the strong magnetic block.

2. The device for applying a sudden unbalanced load to a simulated rotor according to claim 1, characterized in that, The side of the wheel groove has a wheel groove side hole, the side of the strong magnet has a strong magnet side hole, and the wheel groove side hole is a threaded through hole.

3. The device for applying a sudden unbalanced load to a simulated rotor according to claim 2, characterized in that, The axes of the wheel groove side hole and the strong magnetic block side hole are both at an angle of 45° with their sides.

4. The device for applying a sudden unbalanced load to a simulated rotor according to claim 1, characterized in that, The fixing screw for the strong magnetic block is an internal hexagon screw.

5. A method of using the device for applying a sudden unbalanced load to a simulated rotor according to any one of claims 1-4, characterized in that, Includes the following steps: Step 1: Install the high-temperature ceramic heating element, strong magnetic block, unbalanced mass block, unbalanced mass compensation block, strong magnetic block fixing screw and conductive slip ring on the wheel and shaft to form an unbalanced load application device. Then, use the wheel dynamic balancing hole to dynamically balance the rotor system to reduce the initial unbalance of the rotor. Step 2: When the rotor reaches a specific speed, the speed is kept constant. Power is supplied to the high-temperature ceramic heating element on the unbalanced side of the wheel, so that the temperature of the strong magnetic block on that side rises and loses part of its magnetism. When the magnetic attraction force on the unbalanced mass block on that side is less than the centrifugal force, it will fly off the wheel, realizing the sudden addition of the unbalanced load on the rotor. Step 3: After the rotor unbalanced load is suddenly applied, power is supplied to the high-temperature ceramic heating element on the other side to make the unbalanced mass compensation block fly off the wheel disk, thereby compensating for the rotor unbalanced load. Step four: After the test is completed, replace the unbalanced mass block and the unbalanced mass compensation block to start a new round of unbalanced load application test.

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