CN108593229B - Integral impeller blade vibration measurement device and measurement method - Google Patents

Abstract

The invention provides an integral impeller blade vibration measurement device and measurement method, comprising a test bench and an impeller assembly, the impeller assembly is installed on the test bench; the impeller assembly includes an integral impeller (2), a piezoelectric sheet vibration system , data storage equipment and data acquisition equipment; piezoelectric sheet excitation system includes piezoelectric sheet (6), and described piezoelectric sheet (6) and data acquisition equipment are all installed on the integral impeller (2); data acquisition equipment is connected to on the data storage device. The present invention also provides a method for measuring the vibration of the integral impeller blade using the above-mentioned integral impeller blade vibration measuring device. The measuring device provided by the invention can make the measured overall impeller vibrate under the required order of engine excitation, and obtain the vibration data of the blade, which can be used for blade vibration measurement and effect prediction of blade vibration damping treatment measures.

Description

Integral impeller blade vibration measurement device and measurement method

technical field

The invention relates to the field of vibration reduction, in particular to a device and method for measuring the vibration of an integral impeller blade.

Background technique

Stress fracture failures caused by high-cycle fatigue of engine blades due to airflow excitation account for up to 40% of engine failures. In order to save fuel consumption, the development trend is to widely adopt integral impeller (also known as integral blade disc) or integral leaf ring technology. The integral impeller structure integrates the blade and the wheel through casting or forging, or welds the finished single blade to the outer edge of the wheel with electron beam welding to form a whole. Although the weight reduction of the overall impeller can be as high as 25-40%, the structural damping ratio drops to the order of 0.01%, and some traditional friction damping treatment technologies such as shoulders and blades are no longer feasible. In order to reduce the risk of excessive stress caused by airflow excitation instability, it is usually necessary to perform dry friction damping treatment on the overall impeller. In order to effectively predict the effect of dry friction damping treatment, it is necessary to establish a vibration test device for the blade of the overall impeller (including friction damping treatment measures). There are significant differences in the vibration test and damping treatment effect prediction of the blade in the integral impeller and the traditional impeller with separate blade and disc design. In the integral impeller, the blades are no longer connected one by one through the tenon of the rotor blade installed in the tenon groove of the wheel disc, and the damping treatment measures are not for frictional damping between two blades, so it is impossible to take out one or more blades. The test for each blade must be tested for the entire impeller; at the same time, the effect of frictional damping treatment measures depends on the centrifugal force generated by the rotation of the impeller, so the speed of the entire impeller when it rotates at high speed must also be considered. At present, there are not many measurement measures for the vibration response of the blade in the integral impeller under the rotating state. The main difficulties are: first, the influence of high-speed rotation speed, high speed leads to increased requirements for alignment; second, the influence of airflow excitation force, especially in the rotating state, how to reliably apply the excitation force of each order is difficult The third is the impact of data acquisition, especially under high-speed rotation, how the acquisition instrument does not affect the aerodynamics and the rotational unbalance of the overall impeller, and how the storage device stores it.

Contents of the invention

Aiming at the defects in the prior art, the object of the present invention is to provide a vibration measuring device and method for the overall impeller blade.

The overall impeller blade vibration measuring device provided according to the present invention includes a test stand and an impeller assembly, and the impeller assembly is installed on the test stand;

The impeller assembly includes an integral impeller, a piezoelectric sheet excitation system, a data storage device, and a data acquisition device; the piezoelectric sheet excitation system includes a piezoelectric sheet, and the piezoelectric sheet and the data acquisition device are installed on the integral impeller;

The data acquisition device is connected to the data storage device.

Preferably, the piezoelectric sheet excitation system further includes a control device and a piezoelectric sheet exciter control switch; the control device, the piezoelectric sheet exciter control switch, and the piezoelectric sheet are connected in sequence;

A plurality of piezoelectric sheets are fixedly installed on the spokes of the integral impeller along the circumferential direction of the integral impeller.

Preferably, the spokes are provided with piezoelectric sheets on the upstream and downstream surfaces along the flow direction of the simulated airflow excitation generated by the piezoelectric sheet excitation system, and the piezoelectric sheets on the upstream surface and the piezoelectric sheets on the downstream surface There is an installation angle difference between the discs along the circumferential direction of the spokes;

The control device is installed at the center of the integral impeller.

Preferably, the data acquisition device includes an acceleration sensor and a strain gauge sensor installed on the blade of the integral impeller;

The data acquisition equipment is evenly arranged along the circumferential direction of the impeller.

Preferably, the test bench includes a fastened transmission shaft and a mounting disc;

The integral impeller, the control device and the control switch of the piezoelectric vibrator are all installed on the installation disk.

Preferably, the data storage device comprises an online storage electronic box arranged at the center of the installation disc;

The online storage electronic box includes a timer, a memory card, a USB interface and an A/D conversion module.

Preferably, the transmission shaft is a hollow transmission shaft with an axial through hole;

One of the two ends of the hollow transmission shaft in the axial direction is connected to the installation disc, and a slip ring is installed on the other end. The data signal line connected to the data acquisition device passes through the axial through hole in the hollow transmission shaft and connects with the Slip ring connected;

A data storage device is connected to the slip ring.

Preferably, the test bench also includes a motor and a support;

The motor is connected with the hollow transmission shaft, and the hollow transmission shaft is installed on the bracket through the set bearing;

An encoder is also arranged on the other end of the hollow transmission shaft along the axial direction.

Preferably, a vacuum chamber is also included, and an accommodating space is formed inside the vacuum chamber, and the installation disk and the integral impeller are both arranged in the accommodating space;

The hollow transmission shaft extends from the space outside the accommodation space through the vacuum chamber to reach the accommodation space and then connects with the installation disc;

The hollow transmission shaft is connected with the vacuum chamber through a rotary seal; the vacuum chamber is also provided with a vacuum pump and a vacuum gauge.

The present invention also provides a method for measuring the vibration of the integral impeller blade using the above-mentioned integral impeller blade vibration measuring device, comprising the following steps:

Vacuum extraction step: turn on the vacuum pump, and turn off the vacuum pump when the vacuum degree in the accommodation space reaches the set value;

Steps for obtaining simulated airflow excitation: make the control device apply a set level to the control switch of the piezoelectric vibrator to control the voltage in the piezoelectric film;

Data acquisition step: turn on the motor, and let the data acquisition equipment collect the vibration data of the blade;

Data storage step: make the data storage device store the blade vibration data.

Compared with the prior art, the present invention has the following beneficial effects:

1. The measuring device provided by the present invention can make the measured overall impeller vibrate under the required order of engine excitation, and obtain the vibration data of the blade, which can be used for blade vibration measurement and effect prediction of blade vibration damping treatment measures.

2. The present invention solves the technical problem that the existing blade response vibration test cannot take into account excitation simulation and response test under high-speed rotation.

3. The online storage module in the present invention is arranged in the center of the wheel disc. When the data is stored to a certain capacity, the memory card is taken out for offline data processing; at the same time, the alignment of the acceleration sensor and the strain gauge sensor on the blade surface is symmetrical along the blade surface distribution, reducing the impact on misalignment performance of high-speed rotating blades.

4. The structure of the present invention is simple and reasonable, and the operation is reliable.

Description of drawings

Other characteristics, objects and advantages of the present invention will become more apparent by reading the detailed description of non-limiting embodiments made with reference to the following drawings:

Fig. 1 is the structure schematic diagram of the overall impeller blade vibration measuring device provided by the present invention;

Fig. 2 is a schematic diagram of the installation position of the piezoelectric sheet excitation system and data acquisition equipment;

Figure 3 shows the 0, 1, 2, and 4th order excitations eradicated by the piezoelectric sheet excitation system.

The figure shows:

Detailed ways

The present invention will be described in detail below in conjunction with specific embodiments. The following examples will help those skilled in the art to further understand the present invention, but do not limit the present invention in any form. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

In describing the present invention, it is to be understood that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", The orientation or positional relationship indicated by "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying the referred device Or elements must have a certain orientation, be constructed and operate in a certain orientation, and thus should not be construed as limiting the invention.

The device for measuring the vibration of the integral impeller blade provided by the present invention comprises a test stand and an impeller assembly, and the impeller assembly is installed on the test stand. The impeller assembly includes an integral impeller 2, a piezoelectric sheet excitation system, a data storage device, and a data acquisition device. The piezoelectric sheet excitation system includes a piezoelectric sheet 6, and the piezoelectric sheet 6 and the data acquisition device are installed in the overall On the impeller 2, the data acquisition device is connected to the data storage device. The data acquisition equipment includes acceleration sensors 7 and strain gauge sensors 8 installed on the blades of the integral impeller 2, and the data acquisition equipment is evenly arranged along the circumferential direction of the impeller. Correspondingly, the routing of the data acquisition equipment is also along the blade surface Symmetrical distribution to reduce the impact of high-speed rotating blade misalignment performance. Preferably, the data collection device is fixed on the blade by sticking.

The piezoelectric plate vibration system also includes a control device 4 and a piezoelectric plate vibrator control switch 5; the control device 4, the piezoelectric plate vibrator control switch 5, and the piezoelectric plate 6 are connected in sequence, and a plurality of piezoelectric plates 6 is fixedly installed on the spokes of the integral impeller 2 along the circumferential direction of the integral impeller 2. The spokes are provided with piezoelectric sheets 6 on the upstream and downstream surfaces along the flow direction of the simulated airflow excitation generated by the piezoelectric sheet excitation system, and the piezoelectric sheets 6 on the upstream surface and the piezoelectric sheets on the downstream surface 6 There is an installation angle difference along the circumferential direction of the spokes. Preferably, the piezoelectric sheet 6 is pasted on the spokes by an insulating and silver conductive epoxy adhesive. Preferably, the control device 4 is installed at the center of the integral impeller 2, so as to reduce the influence of the misalignment performance of the high-speed rotating blades.

The test bench includes a fastened transmission shaft and an installation disk 3 , and the integral impeller 2 , control device 4 and piezoelectric sheet vibrator control switch 5 are all installed on the installation disk 3 . In the embodiment, the transmission shaft is a hollow transmission shaft 9 with an axial through hole, one of the two ends of the hollow transmission shaft in the axial direction is connected to the installation disc 3, and a slip ring 13 is installed on the other end, The data signal line connected on the data acquisition device passes through the axial through hole in the hollow transmission shaft 9 and is connected with the slip ring 13, and the data storage device is connected with the slip ring 13, so that the blade vibration data collected by the data acquisition device can be real-time Pass through the slip ring 13 to the data storage device. In the variation example, the data storage device includes an online storage electronic box arranged in the center of the installation disk 3, and the online storage electronic box includes a timer, a memory card, a USB interface and an A/D conversion module. When data storage When a certain capacity is reached, the memory card is taken out for offline data processing. The online storage electronic box is arranged in the center of the installation disk 3 to reduce the impact on the misalignment performance of the high-speed rotating blade.

The test bench also includes a motor 11 and a support, the motor 11 is connected with the hollow transmission shaft 9, the hollow transmission shaft 9 is installed on the support through the provided bearing 10, and the other end of the hollow transmission shaft 9 along the axial direction is also provided with Encoder 12. In addition, the measuring device provided by the present invention further includes a vacuum chamber 1, and an accommodation space is formed inside the vacuum chamber 1, and the installation disk 3 and the integral impeller 2 are both arranged in the accommodation space. The hollow transmission shaft 9 extends from the space outside the accommodation space through the vacuum chamber 1 to reach the accommodation space and then connects with the installation disc 3 . The hollow transmission shaft 9 and the vacuum chamber 1 are connected by a rotary seal 15 . The vacuum chamber 1 is also provided with a vacuum pump 14 and a vacuum gauge 16 . Preferably, measuring devices such as pressure thermometers and tachometers for monitoring can also be set on the vacuum chamber 1 and the test bench, and the signals generated by these measuring devices can also be transmitted to the data storage device for storage.

The present invention also provides a method for measuring the vibration of the integral impeller blade using the above-mentioned integral impeller blade vibration measuring device, which includes the following steps: vacuum pumping step: open the vacuum pump 14, and when the vacuum degree in the containing space reaches the set value, close the Vacuum pump 14; analog airflow excitation acquisition step: make the control device 4 apply a set level to the piezoelectric plate vibrator control switch 5, and control the voltage in the piezoelectric plate 6; data acquisition step: turn on the motor 11, make The data acquisition device collects the blade vibration data; the data storage step: the data storage device stores the blade vibration data.

Preferred implementation mode:

The structure of the overall impeller blade vibration measuring device in the rotating state of the present invention is shown in FIG. 1 . Vacuum chamber 1 provides a vacuum environment for the vibration test of the overall impeller blade, which can effectively eliminate the influence of aerodynamics. Vacuum chamber 1 is preferably made of high-strength transparent materials. It is necessary to carry out rubber sealing treatment on the basis of the bolt connection; the joints between the hollow transmission shaft 9 and the slip ring 13 also need to be sealed. Under the action of the vacuum pump 14, the air in the vacuum chamber 1 is extracted, and the vacuum degree in the vacuum chamber 1 is monitored by the vacuum gauge 16. When the required vacuum degree is reached, the vacuum pump 14 stops working, and the measurement can be started at this time. To work, that is, the vacuum pump 14 must be in the off state during the blade vibration test. The pressure in the vacuum chamber 1 is maintained at about 20 mbar by a two-stage vane pump instead of the lowest 1 mbar, which is for the best performance of the piezoelectric sheet 6 .

The integral impeller 2 is loaded on the end of the hollow transmission shaft 9 located in the vacuum chamber 1 through the installation disc 3. The installation disc 3 should simulate the connection device of the integral impeller 2 installed in the actual steam turbine as much as possible; the other end of the hollow transmission shaft 9 is connected to The motor 11 rotates at a high speed to provide power, and drives the integral impeller 2 to rotate at a high speed through the hollow transmission shaft 9 . The hollow transmission shaft 9 is supported by two sets of bearings 10 at the left and right ends. Since the hollow drive shaft 9 needs to pass through an end face of the vacuum chamber 1 , the rotary seal 15 is used to ensure that the sealing performance of the vacuum chamber 1 will not be affected. In addition, the hollow transmission shaft 9 needs wiring, including the power supply line of the piezoelectric sheet 6 , the control line of the control device 4 , the cable of the encoder 12 , the wiring of the acceleration sensor 7 and the wiring of the strain gauge sensor 8 . In order to realize the transmission of data between the moving and static parts, a slip ring 13 is connected to the end of the hollow transmission shaft 9 .

As shown in Figure 2, the piezoelectric sheet 6 in the piezoelectric sheet excitation system is pasted on the spokes of the integral impeller along the circumferential direction through insulating and silver conductive epoxy adhesives, and N a piezoelectric film. The control device 4 is arranged in the center of the installation disc 3 to minimize the influence on misalignment and unbalance. The control switches 5 of the piezoelectric sheet vibrator are symmetrically arranged on the circumference of the installation disk 3 . The piezoelectric sheet works in d ₃₁ mode. The control device 4 applies a corresponding level to control the voltage in the piezoelectric sheet to the control switch 5 of the piezoelectric sheet vibrator, and controls the phase of the excitation force of the piezoelectric sheet to achieve the required order excitation; at the same time, the two upstream and downstream There is a certain angle difference between the groups of piezoelectric plates 6 , and the voltage analog traveling wave excitation of sine and cosine modes is respectively provided by the control device 4 . As shown in Figure 3, taking N=60 piezoelectric sheets 6 as an example, when the phases of each piezoelectric sheet are properly controlled, the 0-order, 1-order, 2-order, and 4-order excitation forces (corresponding to the pitch diameter are respectively 0, 1, 2, 4, and the excitation forces of other orders can be obtained in the same way), due to the coupling between the rim part and the blade, the excitation force of each order provided by the piezoelectric sheet 6 can be applied to the blade .

As shown in Figure 2, the small-sized high-sensitivity acceleration sensor 7 and the small-sized high-sensitivity strain gauge sensor 8 pasted on the blade surface of the integral impeller 2 can collect the data of the blade vibration response. When pasting and arranging, the blade surface The wiring of the acceleration sensor 7 and the strain gauge sensor 8 is distributed symmetrically along the surface of the blade first, so as to reduce the impact on the misalignment performance of the high-speed rotating blade.

One embodiment of the data storage device is to store through the online storage electronic box arranged in the center of the installation disk 3, and the online storage electronic box includes a timer, a memory card, a USB interface, and an A/D conversion module. The online storage electronic box is arranged in the center of the installation disk 3 to reduce the impact on the misalignment performance of the high-speed rotating blade. When the data is stored to a certain capacity, take out the memory card for offline data processing.

Another embodiment of the data storage device is to connect the signal line of the data collected by the acceleration sensor 7 and the strain gauge sensor 8 on the surface of the blade to the moving end of the slip ring 13 through the hollow transmission shaft 9, and the other end of the slip ring 13 transmits the data in real time. passed to the data storage device. The pressure thermometer and tachometer signals used for monitoring are also stored in this way.

Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art may make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. In the case of no conflict, the embodiments of the present application and the features in the embodiments can be combined with each other arbitrarily.

Claims (8)

1. a kind of Integral impeller blade vibration measurement device, which is characterized in that include experimental stand and impeller assembly, impeller assembly It is mounted on experimental stand；

The impeller assembly includes integral wheel (2), piezoelectric patches excitation system, data storage device and data acquisition equipment； Piezoelectric patches excitation system includes piezoelectric patches (6), and the piezoelectric patches (6) and data acquisition equipment are installed on integral wheel (2)；

Data acquisition equipment is connected on data storage device；

The piezoelectric patches excitation system also includes control device (4) and piezoelectric patches vibration excitor control switch (5)；Control device (4), Piezoelectric patches vibration excitor control switch (5), piezoelectric patches (6) are sequentially connected；

Multiple piezoelectric patches (6) are fixedly mounted on the spoke of integral wheel (2) along integral wheel (2) circumferential direction；

Spoke is equal on the upstream face and downstream face on the flow direction of the simulation flow-induced vibration generated along piezoelectric patches excitation system It is provided with piezoelectric patches (6), the piezoelectric patches (6) on upstream face is deposited with the piezoelectric patches (6) on downstream face in spoke circumferential direction It is poor in setting angle；

The control device (4) is mounted on the center of integral wheel (2).

2. Integral impeller blade vibration measurement device according to claim 1, which is characterized in that the data acquisition equipment Acceleration transducer (7) and strain-ga(u)ge transducer (8) on blade comprising being mounted on integral wheel (2)；

Data acquisition equipment is evenly arranged in impeller circumferential direction.

3. Integral impeller blade vibration measurement device according to claim 1, which is characterized in that the experimental stand includes The transmission shaft being fastenedly connected and installation disk (3)；

The integral wheel (2), control device (4) and piezoelectric patches vibration excitor control switch (5) are installed in installation disk (3) On.

4. Integral impeller blade vibration measurement device according to claim 3, which is characterized in that the data storage device Include the on-line storage electronic box being arranged on installation disk (3) center；

The on-line storage electronic box includes timer, RAM card, USB interface and A/D conversion module.

5. Integral impeller blade vibration measurement device according to claim 3, which is characterized in that the transmission shaft be with The Hollow Transmission Shafts (9) of axially extending bore；

Wherein one end in the both ends of Hollow Transmission Shafts in axial direction is connected with installation disk (3), and cunning is equipped on the other end Ring (13), the data signal line connected on data acquisition equipment pass through after the axially extending bore in Hollow Transmission Shafts (9) with slip ring (13) it is connected；

Data storage device is connected with the slip ring (13).

6. Integral impeller blade vibration measurement device according to claim 5, which is characterized in that experimental stand also includes electricity Machine (11) and bracket；

Motor (11) is connected with Hollow Transmission Shafts (9), and Hollow Transmission Shafts (9) are rack-mount by the bearing (10) of setting；

Encoder (12) are additionally provided on the other end of the Hollow Transmission Shafts (9) in axial direction.

7. Integral impeller blade vibration measurement device according to claim 6, which is characterized in that also include vacuum chamber (1), Accommodation space is formed inside vacuum chamber (1), the installation disk (3) and integral wheel (2) are arranged in accommodation space；

Hollow Transmission Shafts (9) reach rear in accommodation space and installation from spatially extended run through vacuum chamber (1) except accommodation space Disk (3) is connected；

It is connect between Hollow Transmission Shafts (9) and vacuum chamber (1) by rotating seal (15)；It is also set up on the vacuum chamber (1) There are vacuum pump (14) and vacuometer (16).

8. a kind of integral wheel leaf using Integral impeller blade vibration measurement device described in any one of any one of claims 1 to 77 Piece vibration measurement method, which is characterized in that comprise the steps of:

Vacuum drawn step: opening vacuum pump (14), after the vacuum degree in accommodation space reaches setting value, closes vacuum pump (14)；

Simulation flow-induced vibration forming steps: control device (4) are enabled to apply the electricity of setting to piezoelectric patches vibration excitor control switch (5) Flat, in control piezoelectric patches (6) voltage；

Data acquisition step: opening motor (11), and data acquisition equipment is enabled to acquire blade vibration data；

Data storing steps: data storage device is enabled to store blade vibration data.