A horizontal-arrangement rotor oiling test bench and a test method thereof

Abstract

The application provides a horizontally placed rotor oil accumulation test bed and a test method thereof. The test bed structure is as follows: a motor is fixed on a main shaft, the main shaft is fixed on a first bearing base and a second bearing base through bearings, and a test chamber is fixed on a non-driving end side of the main shaft; a pump oil hole for injecting fluid is arranged on a side of the laboratory; a hollow shaft sleeve is coaxially fixed on the main shaft through a hollow shaft sleeve support, vertical / horizontal alignment assemblies respectively penetrate vertical / horizontal positioning rods, springs are arranged on the vertical alignment assembly to adjust the support stiffness and coaxiality; a displacement sensor is arranged on the inside of the bearing base to monitor the dynamic response of the rotor-bearing assembly in real time. The test method replicates a rotating machine that captures the asynchronous response of fluid in the laboratory. Through the integrated suspension configuration, flexible support, coaxial damping and adjustable alignment design, the application solves the key problems that the traditional rotor test bed cannot simulate the fluid behavior in the horizontal gravity field, the vibration interference is large at the critical speed, and the observation data is distorted.

Description

Technical Field

[0001] This invention belongs to the field of vibration testing and high-speed camera testing technology, specifically relating to a horizontally placed rotor oil accumulation test bench and its testing method. Background Technology

[0002] In recent years, high-speed rotating machinery has generally adopted high-speed, lightweight structures. While this trend improves rotor performance, it also brings some challenges, particularly the potential for dynamic instability or even instability in aero-engine systems. Therefore, studying the dynamic stability of aero-engine systems has become a key research direction in the field of modern rotor dynamics. Traditional rotor test benches cannot simulate the influence of a horizontal gravitational field on fluid distribution, and rigid support structures struggle to capture liquid surface fluctuations at the first critical speed. Furthermore, the lack of alignment adjustment mechanisms leads to distorted vibration interference data. Summary of the Invention

[0003] The technical problem to be solved by this invention is to conduct theoretical analysis and experimental verification through simulation experiments to gain a deeper understanding of the impact of viscous incompressible fluids such as oil in aero engines, and to further study how to adjust the dynamic parameters of aero engines to improve their stability, thereby providing important reference for the design and optimization of aero engines.

[0004] To solve the above technical problems, the present invention adopts the following technical solution: This invention proposes a horizontally placed rotor oil accumulation test bench, which includes: a motor, a main shaft, a hollow bushing, a hollow bushing support, a test chamber, an acrylic window, an oil pump hole, a slot, a first bearing base, a second bearing base, a vertical alignment assembly, a horizontal alignment assembly, a probe, a spring, a vertical positioning rod, a horizontal positioning rod, and a bearing; wherein: The test chamber is fixed to the right side of the non-drive end of the spindle via a slot, forming an over-suspension configuration. A high-speed camera with a frame rate of ≥2000 fps is installed outside the plexiglass window of the test chamber to capture asymmetric hydraulic jump waves formed by surface fluctuations in the liquid. A pump port for injecting fluid is located next to the test chamber, which is connected to a remotely controlled metering pump with a fluid injection accuracy error of ≤±0.05 mm.

[0005] The hollow bushing is coaxially fixed to the main shaft via a hollow bushing support, and both ends are fixed to the first bearing base and the second bearing base. The first and second bearing bases are connected to the hollow bushing via a flexible support structure. This flexible support structure consists of cantilever beam elements in a squirrel cage configuration, providing low lateral stiffness and high angular stiffness. The flexible support structure includes adjustable bolts, allowing continuous adjustment of the system's support stiffness by changing the bolt preload, with an adjustment range of 0.5–5 kN / mm. The number of cantilever beam elements is 4–8, evenly distributed circumferentially, transforming the system's first-order vibration mode into a cylindrical shape. The probe is a displacement sensor, fixed inside the second bearing base, used to monitor the dynamic response of the rotor-bearing assembly in real time.

[0006] The vertical alignment component and the horizontal alignment component pass through the vertical positioning rod and the horizontal positioning rod respectively, and are equipped with springs to adjust the support stiffness and coaxiality; the elongation of the springs is adjustable to change the stiffness of the vertical alignment component, wherein the spring stiffness coefficient is 50–200 N / mm.

[0007] Furthermore, the present invention also proposes a method for testing rotor oil accumulation, comprising the following steps: (a) Place the test bench horizontally and adjust the coaxiality of the spindle and bearing base by using the vertical / horizontal alignment components; (b) Inject fluid into the test chamber through the pump oil hole, weigh and record the fluid volume and calculate the depth; (c) Start the motor to drive the spindle to accelerate to 8000 rpm, and at the same time monitor the asynchronous response frequency of the rotor-bearing assembly in the test chamber through the displacement sensor; (d) Record fluid surface fluctuations using a high-speed camera and analyze the relationship between wave height and rotation frequency; (e) Repeat steps (b)-(d) to compare the asynchronous response characteristics under different fluid depths and hollow bushing damping conditions.

[0008] Furthermore, in step (e), when there is no damping inside the hollow bushing, the fluid injection depth is 0.635 mm, and the asynchronous response starts at 3753 rpm; when the hollow bushing is lubricated with VG-2 oil, the fluid injection depth is ≥1.65 mm, and the asynchronous response frequency first decreases and then stabilizes with increasing depth, and the frequency remains constant when the depth reaches 4.826 mm.

[0009] Furthermore, the method proposed in this invention also includes a repeated test step, adjusting the support stiffness of the system by changing the preload of the cantilever beam bolts, and comparing the critical speed offset of the asynchronous response under different stiffness conditions.

[0010] The present invention adopts the above technical solution and has the following technical effects compared with the prior art: 1. High-precision dynamic characteristic simulation: The first-order vibration mode of the system is transformed from conical to cylindrical by the flexible support structure (squirrel cage cantilever beam), reducing the first-order critical speed to 1200 rpm. At this speed, the liquid instability phenomenon under actual working conditions is successfully reproduced. At the same time, combined with the adjustable bolt preload and spring elongation adjustment, the support stiffness is continuously adjustable from 0.5 to 5 kN / mm, providing an experimental basis for studying the liquid-induced vibration characteristics under different stiffness conditions.

[0011] 2. High-definition capture of complex fluid behavior: The oversuspension configuration of the laboratory effectively isolates axial disturbances, allowing the liquid film to form stable fluctuations when passing through the critical speed; with the help of a high-speed camera of ≥2000 fps, four asymmetric hydraulic jump waves were observed in the experiment, and the wave height was positively correlated with the fluid depth (the wave height was as high as 3.2 mm at a depth of 17 mm).

[0012] 3. Improved experimental accuracy and reliability: The coaxial design of the hollow bushing controls the coaxiality deviation between the spindle and the bearing base to ≤0.01 mm, reducing the vibration amplitude by 40% under high-speed rotation (8000 rpm); the remote metering pump precisely controls fluid injection with a depth error of ≤±0.05 mm, ensuring the repeatability of asynchronous response start frequency data (0.635 mm / 3753 rpm under undamped conditions; 1.65 mm start frequency deviation under damped conditions <5%).

[0013] 4. Engineering application value: This test rig provides direct experimental evidence for the study of oil accumulation dynamics in aero-engine rotor systems, and in particular reveals the nonlinear influence of fluid depth on the asynchronous response start frequency and the quantitative relationship between external damping and critical speed offset. Attached Figure Description

[0014] Figure 1 This is a diagram of a first bearing base assembly in one embodiment.

[0015] Figure 2 This is a diagram of the second bearing base assembly in one embodiment.

[0016] Figure 3 This is a laboratory diagram from one embodiment.

[0017] Figure 4 This is a cross-sectional view of the test bench in one embodiment.

[0018] Figure 5 This is a top view of the test bench in one embodiment. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the described embodiments of this application are within the scope of protection of this application.

[0020] Unless otherwise defined, the technical or scientific terms used in this application shall have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. The terms "first," "second," and similar terms used in this application do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship also changes accordingly.

[0021] In one embodiment, such as Figures 1-5 As shown, the present invention provides a horizontally placed rotor oil accumulation test bench, the horizontally placed rotor oil accumulation test bench comprising: Motor 101, spindle 102, hollow bushing 103, hollow bushing support 104, test chamber 105, plexiglass window 106, pump oil hole 107, slot 108, first bearing base 109, second bearing base 110, vertical alignment components 111, 112, vertical positioning rods 113, 114, springs 115, 116, horizontal alignment components 117, 118, horizontal positioning rods 119, 120, bearings 121, 122, probe 123.

[0022] The motor 101 is fixed on the spindle 102. The test chamber 105 is fixed to the right side of the spindle 102 via the slot 108. The plexiglass window 106 is fixed outside the test chamber 105. The oil pump hole 107 is located beside the laboratory 104. The spindle 102 is fixed to the first bearing base 109 and the second bearing base 110 via bearings 121 and 122. The hollow bushing 103 is supported by the hollow bushing support 104 and fixed to the first bearing base 109 and the second bearing base 110, ensuring that the spindle 102 is coaxial with the first bearing base 109 and the second bearing base 110. The horizontal alignment assembly 117 passes through the horizontal positioning rod 119, the horizontal alignment assembly 118 passes through the horizontal positioning rod 120, the vertical alignment assembly 111 passes through the vertical positioning rod 113, the spring 115 is located in the device for fixing the vertical positioning rod 113, the vertical alignment assembly 112 passes through the vertical positioning rod 114, the spring 116 is located in the device for fixing the vertical positioning rod 114, and the probe 123 is fixed to the second bearing base 110 for monitoring the rotor-bearing assembly response at the test chamber 105.

[0023] In one embodiment, the first bearing base assembly includes: a first bearing base 109, a vertical alignment assembly 111, a horizontal alignment assembly 117, a spring 115, and a bearing 121.

[0024] The bearing 121 is sleeved on the main shaft 102, the vertical alignment component 111 is located directly above the first bearing base 109, the spring 115 is located in the device that fixes the vertical positioning rod 113, and the rigidity of the device is changed by changing its elongation, and the horizontal alignment component 117 is located on both sides of the first bearing base 109.

[0025] In one embodiment, the second bearing base assembly includes: a second bearing base 110, a vertical alignment assembly 112, a horizontal alignment assembly 118, a spring 116, a bearing 122, and a probe 123.

[0026] The bearing is sleeved on the main shaft 102. The probe 123 is located inside the assembly and is used to fix the bearing 122. The vertical alignment assembly 112 is located directly above the second bearing base 110. The spring 116 is located in the device for fixing the vertical positioning rod and changes the rigidity of the device by changing its elongation. The horizontal alignment assembly 118 is located on both sides of the second bearing base 110.

[0027] In one embodiment, the test chamber assembly includes: a test chamber 105, an acrylic window 106, an oil pump hole 107, and a card slot 108.

[0028] The test chamber 105 is fixed to the main shaft 102 via the slot 108, the plexiglass window 106 is fixed outside the test chamber 105 for easy shooting by a high-definition camera, and the oil pump hole 107 is located beside the test chamber 105.

[0029] This invention also proposes a method for constructing a rotor oil accumulation testing platform. By placing the test bench horizontally and considering the effects of gravity, a real electric motor can be simulated. Multiple tests are conducted, varying the fluid depth and system damping to observe changes in the asynchronous response. The test duration ranges from 30 seconds to 3 minutes, depending on the amount of liquid injected into the test chamber and the acceleration rate. The liquid is remotely injected into the test chamber from the operation control room via a pump. The fluid volume in the pump is weighed before each test. The final test uses a high-speed camera to capture the fluid flow and observe the waves formed on the surface.

[0030] The amount of fluid affects the asynchronous response; sufficient fluid is required to asynchronously excite the system. For undamped tests (without oil in the hollow bushing), liquid is added to the empty test chamber, and the running speed is increased from 0 to 8000 rpm. When the liquid depth is approximately 0.635 mm, the asynchronous response begins at approximately 3753 rpm. As the fluid depth increases, the frequency at which the asynchronous response begins remains relatively constant.

[0031] Adding external damping alters the required fluid depth to asynchronously excite the system. For damped tests (with VG-2 oil lubrication used for the hollow bushing), fluid was added to the test chamber until an asynchronous response was observed at a depth of approximately 1.65 mm. As the fluid depth continued to increase, the frequency at which the asynchronous response began initially decreased and then became relatively constant, reaching a relatively constant frequency when the fluid depth in the laboratory reached approximately 4.826 mm.

[0032] As the liquid volume in the test chamber increased, the wave peaks became larger, so approximately 17 mm of liquid was injected to observe the wave height. The observed waves included: it was expected that only one wave would form on the surface of the oil (hydraulic jump), but when recording the fluid surface, four different waves were observed in one rotation, and the waves were not uniform along the circumference of the test chamber.

[0033] The horizontal rotor oil accumulation test bench and test method provided by this invention solves key problems such as the inability of traditional rotor test benches to simulate the fluid behavior of horizontal gravity fields, large vibration interference at critical speeds, and distortion of observation data by integrating four core designs: oversuspension configuration, flexible support, coaxial vibration reduction, and adjustable alignment. It has good prospects for engineering applications.

[0034] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A horizontally placed rotor oil accumulation test bench, characterized in that, include: Motor (101), spindle (102), hollow bushing (103), hollow bushing support (104), test chamber (105), first bearing base (109), second bearing base (110), vertical alignment assembly (111, 112), horizontal alignment assembly (117, 118), vertical positioning rod (113, 114), horizontal positioning rod (119, 120); Wherein: the motor is fixed on the main shaft, the main shaft is fixed on the first and second bearing bases by bearings, and the test chamber is fixed on the non-drive end side of the main shaft by a slot (108), forming an over-suspension configuration; a pump oil hole (107) for injecting fluid is provided on the side of the test chamber. The hollow bushing is coaxially fixed to the main shaft by a hollow bushing support, and the first and second bearing bases are fixedly connected at both ends. The vertical alignment component and the horizontal alignment component pass through the vertical positioning rod and the horizontal positioning rod respectively, and springs (115, 116) are configured on the vertical alignment component to adjust the support stiffness and coaxiality. A displacement sensor (123) is fixedly installed inside the second bearing base to monitor the dynamic response of the rotor-bearing assembly in real time.

2. The test bench according to claim 1, characterized in that, The first bearing base and the second bearing base are connected to the hollow bushing through a flexible support structure. The flexible support structure is configured as a squirrel cage with cantilever beam elements, providing low lateral stiffness and high angular stiffness.

3. The test bench according to claim 2, characterized in that, The flexible support structure includes adjustable bolts, which allow for continuous adjustment of the system's support stiffness by changing the bolt preload.

4. The test bench according to claim 1, characterized in that, The laboratory has an plexiglass window (106) with a high-speed camera mounted on it to capture asymmetric hydraulic jump waves formed by fluctuations on the liquid surface.

5. The test bench according to claim 1, characterized in that, The spring's elongation is adjustable, allowing for changes in the rigidity of the vertical alignment assembly.

6. The test bench according to claim 1, characterized in that, The pump oil port is connected to a remotely controlled metering pump.

7. The test bench according to claim 2, characterized in that, The number of cantilever beam elements is 4–8, evenly distributed in a circle, which transforms the first-order vibration mode of the system into a cylindrical shape.

8. A rotor oil accumulation test method, based on the test bench according to any one of claims 1-7, characterized in that, Includes the following steps: S1. Place the test bench horizontally and adjust the coaxiality of the spindle with the first and second bearing bases using the vertical alignment component and the horizontal alignment component; S2. Inject fluid into the test chamber through the pump oil hole, weigh and record the fluid volume, and calculate the depth; S3. Start the motor to drive the spindle to accelerate to the set value, and at the same time monitor the asynchronous response frequency of the rotor-bearing assembly in the test chamber through the displacement sensor; S4. Record fluid surface fluctuations using a high-speed camera and analyze the relationship between wave height and rotation frequency; S5. Repeat steps S2-S4 to compare the asynchronous response characteristics under different fluid depths and hollow bushing damping conditions.

9. The method according to claim 8, characterized in that: In step S5, when there is no damping inside the hollow bushing, the fluid injection depth is 0.635 mm, and the asynchronous response starts at 3753 rpm; when the hollow bushing is lubricated with VG-2 oil, the fluid injection depth is ≥1.65 mm, and the asynchronous response frequency first decreases and then stabilizes with the increase of depth, and the frequency is constant when the depth reaches 4.826 mm.

10. The method according to claim 8, characterized in that: It also includes repeated testing steps, adjusting the system support stiffness by changing the preload of the cantilever beam bolts, and comparing the critical speed deviation of the asynchronous response under different stiffness conditions.

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